Index: trunk/src/whizard-core/whizard.nw
===================================================================
--- trunk/src/whizard-core/whizard.nw	(revision 8346)
+++ trunk/src/whizard-core/whizard.nw	(revision 8347)
@@ -1,31314 +1,31389 @@
 % -*- ess-noweb-default-code-mode: f90-mode; noweb-default-code-mode: f90-mode; -*-
 % WHIZARD main code as NOWEB source
 \includemodulegraph{whizard-core}
 \chapter{Integration and Simulation}
 @
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{User-controlled File I/O}
 
 The SINDARIN language includes commands that write output to file (input may
 be added later).  We identify files by their name, and manage the unit
 internally.  We need procedures for opening, closing, and printing files.
 
 <<[[user_files.f90]]>>=
 <<File header>>
 
 module user_files
 
 <<Use strings>>
   use io_units
   use diagnostics
   use ifiles
   use analysis
 
 <<Standard module head>>
 
 <<User files: public>>
 
 <<User files: types>>
 
 <<User files: interfaces>>
 
 contains
 
 <<User files: procedures>>
 
 end module user_files
 @ %def user_files
 @
 \subsection{The file type}
 This is a type that describes an open user file and its properties.  The entry
 is part of a doubly-linked list.
 <<User files: types>>=
   type :: file_t
      private
      type(string_t) :: name
      integer :: unit = -1
      logical :: reading = .false.
      logical :: writing = .false.
      type(file_t), pointer :: prev => null ()
      type(file_t), pointer :: next => null ()
   end type file_t
 
 @ %def file_t
 @ The initializer opens the file.
 <<User files: procedures>>=
   subroutine file_init (file, name, action, status, position)
     type(file_t), intent(out) :: file
     type(string_t), intent(in) :: name
     character(len=*), intent(in) :: action, status, position
     file%unit = free_unit ()
     file%name = name
     open (unit = file%unit, file = char (file%name), &
           action = action, status = status, position = position)
     select case (action)
     case ("read")
        file%reading = .true.
     case ("write")
        file%writing = .true.
     case ("readwrite")
        file%reading = .true.
        file%writing = .true.
     end select
   end subroutine file_init
 
 @ %def file_init
 @ The finalizer closes it.
 <<User files: procedures>>=
   subroutine file_final (file)
     type(file_t), intent(inout) :: file
     close (unit = file%unit)
     file%unit = -1
   end subroutine file_final
 
 @ %def file_final
 @ Check if a file is open with correct status.
 <<User files: procedures>>=
   function file_is_open (file, action) result (flag)
     logical :: flag
     type(file_t), intent(in) :: file
     character(*), intent(in) :: action
     select case (action)
     case ("read")
        flag = file%reading
     case ("write")
        flag = file%writing
     case ("readwrite")
        flag = file%reading .and. file%writing
     case default
        call msg_bug ("Checking file '" // char (file%name) &
             // "': illegal action specifier")
     end select
   end function file_is_open
 
 @ %def file_is_open
 @ Return the unit number of a file for direct access.  It should be checked
 first whether the file is open.
 <<User files: procedures>>=
   function file_get_unit (file) result (unit)
     integer :: unit
     type(file_t), intent(in) :: file
     unit = file%unit
   end function file_get_unit
 
 @ %def file_get_unit
 @ Write to the file.  Error if in wrong mode.  If there is no string, just
 write an empty record.  If there is a string, respect the [[advancing]]
 option.
 <<User files: procedures>>=
   subroutine file_write_string (file, string, advancing)
     type(file_t), intent(in) :: file
     type(string_t), intent(in), optional :: string
     logical, intent(in), optional :: advancing
     if (file%writing) then
        if (present (string)) then
           if (present (advancing)) then
              if (advancing) then
                 write (file%unit, "(A)")  char (string)
              else
                 write (file%unit, "(A)", advance="no")  char (string)
              end if
           else
              write (file%unit, "(A)")  char (string)
           end if
        else
           write (file%unit, *)
        end if
     else
        call msg_error ("Writing to file: File '" // char (file%name) &
             // "' is not open for writing.")
     end if
   end subroutine file_write_string
 
 @ %def file_write
 @ Write a whole ifile, line by line.
 <<User files: procedures>>=
   subroutine file_write_ifile (file, ifile)
     type(file_t), intent(in) :: file
     type(ifile_t), intent(in) :: ifile
     type(line_p) :: line
     call line_init (line, ifile)
     do while (line_is_associated (line))
        call file_write_string (file, line_get_string_advance (line))
     end do
   end subroutine file_write_ifile
 
 @ %def file_write_ifile
 @ Write an analysis object (or all objects) to an open file.
 <<User files: procedures>>=
   subroutine file_write_analysis (file, tag)
     type(file_t), intent(in) :: file
     type(string_t), intent(in), optional :: tag
     if (file%writing) then
        if (present (tag)) then
           call analysis_write (tag, unit = file%unit)
        else
           call analysis_write (unit = file%unit)
        end if
     else
        call msg_error ("Writing analysis to file: File '" // char (file%name) &
             // "' is not open for writing.")
     end if
   end subroutine file_write_analysis
 
 @ %def file_write_analysis
 @
 \subsection{The file list}
 We maintain a list of all open files and their attributes.  The list must be
 doubly-linked because we may delete entries.
 <<User files: public>>=
   public :: file_list_t
 <<User files: types>>=
   type :: file_list_t
      type(file_t), pointer :: first => null ()
      type(file_t), pointer :: last => null ()
   end type file_list_t
 
 @ %def file_list_t
 @ There is no initialization routine, but a finalizer which deletes all:
 <<User files: public>>=
   public :: file_list_final
 <<User files: procedures>>=
   subroutine file_list_final (file_list)
     type(file_list_t), intent(inout) :: file_list
     type(file_t), pointer :: current
     do while (associated (file_list%first))
        current => file_list%first
        file_list%first => current%next
        call file_final (current)
        deallocate (current)
     end do
     file_list%last => null ()
   end subroutine file_list_final
 
 @ %def file_list_final
 @ Find an entry in the list.  Return null pointer on failure.
 <<User files: procedures>>=
   function file_list_get_file_ptr (file_list, name) result (current)
     type(file_t), pointer :: current
     type(file_list_t), intent(in) :: file_list
     type(string_t), intent(in) :: name
     current => file_list%first
     do while (associated (current))
        if (current%name == name)  return
        current => current%next
     end do
   end function file_list_get_file_ptr
 
 @ %def file_list_get_file_ptr
 @ Check if a file is open, public version:
 <<User files: public>>=
   public :: file_list_is_open
 <<User files: procedures>>=
   function file_list_is_open (file_list, name, action) result (flag)
     logical :: flag
     type(file_list_t), intent(in) :: file_list
     type(string_t), intent(in) :: name
     character(len=*), intent(in) :: action
     type(file_t), pointer :: current
     current => file_list_get_file_ptr (file_list, name)
     if (associated (current)) then
        flag = file_is_open (current, action)
     else
        flag = .false.
     end if
   end function file_list_is_open
 
 @ %def file_list_is_open
 @ Return the unit number for a file.  It should be checked first whether the
 file is open.
 <<User files: public>>=
   public :: file_list_get_unit
 <<User files: procedures>>=
   function file_list_get_unit (file_list, name) result (unit)
     integer :: unit
     type(file_list_t), intent(in) :: file_list
     type(string_t), intent(in) :: name
     type(file_t), pointer :: current
     current => file_list_get_file_ptr (file_list, name)
     if (associated (current)) then
        unit = file_get_unit (current)
     else
        unit = -1
     end if
   end function file_list_get_unit
   
 @ %def file_list_get_unit
 @ Append a new file entry, i.e., open this file.  Error if it is
 already open.
 <<User files: public>>=
   public :: file_list_open
 <<User files: procedures>>=
   subroutine file_list_open (file_list, name, action, status, position)
     type(file_list_t), intent(inout) :: file_list
     type(string_t), intent(in) :: name
     character(len=*), intent(in) :: action, status, position
     type(file_t), pointer :: current
     if (.not. associated (file_list_get_file_ptr (file_list, name))) then
        allocate (current)
        call msg_message ("Opening file '" // char (name) // "' for output")
        call file_init (current, name, action, status, position)
        if (associated (file_list%last)) then
           file_list%last%next => current
           current%prev => file_list%last
        else
           file_list%first => current
        end if
        file_list%last => current
     else
        call msg_error ("Opening file: File '" // char (name) &
             // "' is already open.")
     end if
   end subroutine file_list_open
 
 @ %def file_list_open
 @ Delete a file entry, i.e., close this file.  Error if it is not open.
 <<User files: public>>=
   public :: file_list_close
 <<User files: procedures>>=
   subroutine file_list_close (file_list, name)
     type(file_list_t), intent(inout) :: file_list
     type(string_t), intent(in) :: name
     type(file_t), pointer :: current
     current => file_list_get_file_ptr (file_list, name)
     if (associated (current)) then
        if (associated (current%prev)) then
           current%prev%next => current%next
        else
           file_list%first => current%next
        end if
        if (associated (current%next)) then
           current%next%prev => current%prev
        else
           file_list%last => current%prev
        end if
        call msg_message ("Closing file '" // char (name) // "' for output")
        call file_final (current)
        deallocate (current)
     else
        call msg_error ("Closing file: File '" // char (name) &
             // "' is not open.")
     end if
   end subroutine file_list_close
 
 @ %def file_list_close
 @ Write a string to file.  Error if it is not open.
 <<User files: public>>=
   public :: file_list_write
 <<User files: interfaces>>=
   interface file_list_write
      module procedure file_list_write_string
      module procedure file_list_write_ifile
   end interface
 <<User files: procedures>>=
   subroutine file_list_write_string (file_list, name, string, advancing)
     type(file_list_t), intent(in) :: file_list
     type(string_t), intent(in) :: name
     type(string_t), intent(in), optional :: string
     logical, intent(in), optional :: advancing
     type(file_t), pointer :: current
     current => file_list_get_file_ptr (file_list, name)
     if (associated (current)) then
        call file_write_string (current, string, advancing)
     else
        call msg_error ("Writing to file: File '" // char (name) &
             // "'is not open.")
     end if
   end subroutine file_list_write_string
 
   subroutine file_list_write_ifile (file_list, name, ifile)
     type(file_list_t), intent(in) :: file_list
     type(string_t), intent(in) :: name
     type(ifile_t), intent(in) :: ifile
     type(file_t), pointer :: current
     current => file_list_get_file_ptr (file_list, name)
     if (associated (current)) then
        call file_write_ifile (current, ifile)
     else
        call msg_error ("Writing to file: File '" // char (name) &
             // "'is not open.")
     end if
   end subroutine file_list_write_ifile
 
 @ %def file_list_write
 @ Write an analysis object or all objects to data file.  Error if it is not
 open.  If the file name is empty, write to standard output.
 <<User files: public>>=
   public :: file_list_write_analysis
 <<User files: procedures>>=
   subroutine file_list_write_analysis (file_list, name, tag)
     type(file_list_t), intent(in) :: file_list
     type(string_t), intent(in) :: name
     type(string_t), intent(in), optional :: tag
     type(file_t), pointer :: current
     if (name == "") then
        if (present (tag)) then
           call analysis_write (tag)
        else
           call analysis_write
        end if
     else
        current => file_list_get_file_ptr (file_list, name)
        if (associated (current)) then
           call file_write_analysis (current, tag)
        else
           call msg_error ("Writing analysis to file: File '" // char (name) &
                // "' is not open.")
        end if
     end if
   end subroutine file_list_write_analysis
 
 @ %def file_list_write_analysis
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Runtime data}
 
 <<[[rt_data.f90]]>>=
 <<File header>>
 
 module rt_data
 
 <<Use kinds>>
 <<Use strings>>
   use io_units
   use format_utils, only: write_separator
   use format_defs, only: FMT_19, FMT_12
   use system_dependencies
   use diagnostics
   use os_interface
   use lexers
   use parser
   use models
   use subevents
   use pdg_arrays
   use variables, only: var_list_t
   use process_libraries
   use prclib_stacks
   use prc_core, only: helicity_selection_t
   use beam_structures
   use event_base, only: event_callback_t
   use user_files
   use process_stacks
   use iterations
 
 <<Standard module head>>
 
 <<RT data: public>>
 
 <<RT data: types>>
 
 contains
 
 <<RT data: procedures>>
 
 end module rt_data
 @ %def rt_data
 @
 \subsection{Strategy for models and variables}
 The program manages its data via a main [[rt_data_t]] object.  During program
 flow, various commands create and use local [[rt_data_t]] objects.  Those
 transient blocks contain either pointers to global object or local copies
 which are deleted after use.
 
 Each [[rt_data_t]] object contains a variable list component.  This lists
 holds (local copies of) all kinds of intrinsic or user-defined variables.  The
 variable list is linked to the variable list contained in the local process
 library.  This, in turn, is linked to the variable list of the [[rt_data_t]]
 context, and so on.
 
 A variable lookup will thus be recursively delegated to the linked variable
 lists, until a match is found.  When modifying a variable which is not yet
 local, the program creates a local copy and uses this afterwards.  Thus, when
 the local [[rt_data_t]] object is deleted, the context value is recovered.
 
 Models are kept in a model list which is separate from the variable list.
 Otherwise, they are treated in a similar manner: the local list is linked to
 the context model list.  Model lookup is thus recursively delegated.  When a
 model or any part of it is modified, the model is copied to the local
 [[rt_data_t]] object, so the context model is not modified.  Commands such as
 [[integrate]] will create their own copy of the current model (and of the
 current variable list) at the point where they are executed.
 
 When a model is encountered for the first time, it is read from file.  The
 reading is automatically delegated to the global context.  Thus, this master
 copy survives until the main [[rt_data_t]] object is deleted, at program
 completion.
 
 If there is a currently active model, its variable list is linked to the main
 variable list.  Variable lookups will then start from the model variable
 list.  When the current model is switched, the new active model will get this
 link instead.  Consequently, a change to the current model is kept as long as
 this model has a local copy; it survives local model switches.  On the other
 hand, a parameter change in the current model doesn't affect any other model,
 even if the parameter name is identical.
 @
 \subsection{Container for parse nodes}
 The runtime data set contains a bunch of parse nodes (chunks of code
 that have not been compiled into evaluation trees but saved for later
 use).  We collect them here.
 
 This implementation has the useful effect that an assignment between two
 objects of this type will establish a pointer-target relationship for
 all components.
 <<RT data: types>>=
   type :: rt_parse_nodes_t
      type(parse_node_t), pointer :: cuts_lexpr => null ()
      type(parse_node_t), pointer :: scale_expr => null ()
      type(parse_node_t), pointer :: fac_scale_expr => null ()
      type(parse_node_t), pointer :: ren_scale_expr => null ()
      type(parse_node_t), pointer :: weight_expr => null ()
      type(parse_node_t), pointer :: selection_lexpr => null ()
      type(parse_node_t), pointer :: reweight_expr => null ()
      type(parse_node_t), pointer :: analysis_lexpr => null ()
      type(parse_node_p), dimension(:), allocatable :: alt_setup
    contains
    <<RT data: rt parse nodes: TBP>>
   end type rt_parse_nodes_t
 
 @ %def rt_parse_nodes_t
 @ Clear individual components.  The parse nodes are nullified.  No
 finalization needed since the pointer targets are part of the global
 parse tree.
 <<RT data: rt parse nodes: TBP>>=
   procedure :: clear => rt_parse_nodes_clear
 <<RT data: procedures>>=
   subroutine rt_parse_nodes_clear (rt_pn, name)
     class(rt_parse_nodes_t), intent(inout) :: rt_pn
     type(string_t), intent(in) :: name
     select case (char (name))
     case ("cuts")
        rt_pn%cuts_lexpr => null ()
     case ("scale")
        rt_pn%scale_expr => null ()
     case ("factorization_scale")
        rt_pn%fac_scale_expr => null ()
     case ("renormalization_scale")
        rt_pn%ren_scale_expr => null ()
     case ("weight")
        rt_pn%weight_expr => null ()
     case ("selection")
        rt_pn%selection_lexpr => null ()
     case ("reweight")
        rt_pn%reweight_expr => null ()
     case ("analysis")
        rt_pn%analysis_lexpr => null ()
     end select
   end subroutine rt_parse_nodes_clear
 
 @ %def rt_parse_nodes_clear
 @ Output for the parse nodes.
 <<RT data: rt parse nodes: TBP>>=
   procedure :: write => rt_parse_nodes_write
 <<RT data: procedures>>=
   subroutine rt_parse_nodes_write (object, unit)
     class(rt_parse_nodes_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer :: u, i
     u = given_output_unit (unit)
     call wrt ("Cuts", object%cuts_lexpr)
     call write_separator (u)
     call wrt ("Scale", object%scale_expr)
     call write_separator (u)
     call wrt ("Factorization scale", object%fac_scale_expr)
     call write_separator (u)
     call wrt ("Renormalization scale", object%ren_scale_expr)
     call write_separator (u)
     call wrt ("Weight", object%weight_expr)
     call write_separator (u, 2)
     call wrt ("Event selection", object%selection_lexpr)
     call write_separator (u)
     call wrt ("Event reweighting factor", object%reweight_expr)
     call write_separator (u)
     call wrt ("Event analysis", object%analysis_lexpr)
     if (allocated (object%alt_setup)) then
        call write_separator (u, 2)
        write (u, "(1x,A,':')")  "Alternative setups"
        do i = 1, size (object%alt_setup)
           call write_separator (u)
           call wrt ("Commands", object%alt_setup(i)%ptr)
        end do
     end if
   contains
     subroutine wrt (title, pn)
       character(*), intent(in) :: title
       type(parse_node_t), intent(in), pointer :: pn
       if (associated (pn)) then
          write (u, "(1x,A,':')")  title
          call write_separator (u)
          call parse_node_write_rec (pn, u)
       else
          write (u, "(1x,A,':',1x,A)")  title, "[undefined]"
       end if
     end subroutine wrt
   end subroutine rt_parse_nodes_write
 
 @ %def rt_parse_nodes_write
 @ Screen output for individual components.  (This should eventually be more
 condensed, currently we print the internal representation tree.)
 <<RT data: rt parse nodes: TBP>>=
   procedure :: show => rt_parse_nodes_show
 <<RT data: procedures>>=
   subroutine rt_parse_nodes_show (rt_pn, name, unit)
     class(rt_parse_nodes_t), intent(in) :: rt_pn
     type(string_t), intent(in) :: name
     integer, intent(in), optional :: unit
     type(parse_node_t), pointer :: pn
     integer :: u
     u = given_output_unit (unit)
     select case (char (name))
     case ("cuts")
        pn => rt_pn%cuts_lexpr
     case ("scale")
        pn => rt_pn%scale_expr
     case ("factorization_scale")
        pn => rt_pn%fac_scale_expr
     case ("renormalization_scale")
        pn => rt_pn%ren_scale_expr
     case ("weight")
        pn => rt_pn%weight_expr
     case ("selection")
        pn => rt_pn%selection_lexpr
     case ("reweight")
        pn => rt_pn%reweight_expr
     case ("analysis")
        pn => rt_pn%analysis_lexpr
     end select
     if (associated (pn)) then
        write (u, "(A,1x,A,1x,A)")  "Expression:", char (name), "(parse tree):"
        call parse_node_write_rec (pn, u)
     else
        write (u, "(A,1x,A,A)")  "Expression:", char (name), ": [undefined]"
     end if
   end subroutine rt_parse_nodes_show
 
 @ %def rt_parse_nodes_show
 @
 \subsection{The data type}
 This is a big data container which contains everything that is used and
 modified during the command flow.  A local copy of this can be used to
 temporarily override defaults.  The data set is transparent.
 <<RT data: public>>=
   public :: rt_data_t
 <<RT data: types>>=
   type :: rt_data_t
      type(lexer_t), pointer :: lexer => null ()
      type(rt_data_t), pointer :: context => null ()
      type(string_t), dimension(:), allocatable :: export
      type(var_list_t) :: var_list
      type(iterations_list_t) :: it_list
      type(os_data_t) :: os_data
      type(model_list_t) :: model_list
      type(model_t), pointer :: model => null ()
      logical :: model_is_copy = .false.
      type(model_t), pointer :: preload_model => null ()
      type(model_t), pointer :: fallback_model => null ()
      type(prclib_stack_t) :: prclib_stack
      type(process_library_t), pointer :: prclib => null ()
      type(beam_structure_t) :: beam_structure
      type(rt_parse_nodes_t) :: pn
      type(process_stack_t) :: process_stack
      type(string_t), dimension(:), allocatable :: sample_fmt
      class(event_callback_t), allocatable :: event_callback
      type(file_list_t), pointer :: out_files => null ()
      logical :: quit = .false.
      integer :: quit_code = 0
      type(string_t) :: logfile
      logical :: nlo_fixed_order = .false.
      logical, dimension(0:5) :: selected_nlo_parts = .false.
      integer, dimension(:), allocatable :: nlo_component
    contains
    <<RT data: rt data: TBP>>
   end type rt_data_t
 
 @ %def rt_data_t
 @
 \subsection{Output}
 <<RT data: rt data: TBP>>=
   procedure :: write => rt_data_write
 <<RT data: procedures>>=
   subroutine rt_data_write (object, unit, vars, pacify)
     class(rt_data_t), intent(in) :: object
     integer, intent(in), optional :: unit
     type(string_t), dimension(:), intent(in), optional :: vars
     logical, intent(in), optional :: pacify
     integer :: u, i
     u = given_output_unit (unit)
     call write_separator (u, 2)
     write (u, "(1x,A)")  "Runtime data:"
     if (object%get_n_export () > 0) then
        call write_separator (u, 2)
        write (u, "(1x,A)")  "Exported objects and variables:"
        call write_separator (u)
        call object%write_exports (u)
     end if
     if (present (vars)) then
        if (size (vars) /= 0) then
           call write_separator (u, 2)
           write (u, "(1x,A)")  "Selected variables:"
           call write_separator (u)
           call object%write_vars (u, vars)
        end if
     else
        call write_separator (u, 2)
        if (associated (object%model)) then
           call object%model%write_var_list (u, follow_link=.true.)
        else
           call object%var_list%write (u, follow_link=.true.)
        end if
     end if
     if (object%it_list%get_n_pass () > 0) then
        call write_separator (u, 2)
        write (u, "(1x)", advance="no")
        call object%it_list%write (u)
     end if
     if (associated (object%model)) then
        call write_separator (u, 2)
        call object%model%write (u)
     end if
     call object%prclib_stack%write (u)
     call object%beam_structure%write (u)
     call write_separator (u, 2)
     call object%pn%write (u)
     if (allocated (object%sample_fmt)) then
        call write_separator (u)
        write (u, "(1x,A)", advance="no")  "Event sample formats = "
        do i = 1, size (object%sample_fmt)
           if (i > 1)  write (u, "(A,1x)", advance="no")  ","
           write (u, "(A)", advance="no")  char (object%sample_fmt(i))
        end do
        write (u, "(A)")
     end if
     call write_separator (u)
     write (u, "(1x,A)", advance="no")  "Event callback:"
     if (allocated (object%event_callback)) then
        call object%event_callback%write (u)
     else
        write (u, "(1x,A)")  "[undefined]"
     end if
     call object%process_stack%write (u, pacify)
     write (u, "(1x,A,1x,L1)")  "quit     :", object%quit
     write (u, "(1x,A,1x,I0)")  "quit_code:", object%quit_code
     call write_separator (u, 2)
     write (u, "(1x,A,1x,A)")   "Logfile  :", "'" // trim (char (object%logfile)) // "'"
     call write_separator (u, 2)
   end subroutine rt_data_write
 
 @ %def rt_data_write
 @ Write only selected variables.
 <<RT data: rt data: TBP>>=
   procedure :: write_vars => rt_data_write_vars
 <<RT data: procedures>>=
   subroutine rt_data_write_vars (object, unit, vars)
     class(rt_data_t), intent(in), target :: object
     integer, intent(in), optional :: unit
     type(string_t), dimension(:), intent(in) :: vars
     type(var_list_t), pointer :: var_list
     integer :: u, i
     u = given_output_unit (unit)
     var_list => object%get_var_list_ptr ()
     do i = 1, size (vars)
        associate (var => vars(i))
          if (var_list%contains (var, follow_link=.true.)) then
             call var_list%write_var (var, unit = u, &
                  follow_link = .true., defined=.true.)
          end if
        end associate
     end do
   end subroutine rt_data_write_vars
 
 @ %def rt_data_write_vars
 @ Write only the model list.
 <<RT data: rt data: TBP>>=
   procedure :: write_model_list => rt_data_write_model_list
 <<RT data: procedures>>=
   subroutine rt_data_write_model_list (object, unit)
     class(rt_data_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer :: u
     u = given_output_unit (unit)
     call object%model_list%write (u)
   end subroutine rt_data_write_model_list
 
 @ %def rt_data_write_model_list
 @ Write only the library stack.
 <<RT data: rt data: TBP>>=
   procedure :: write_libraries => rt_data_write_libraries
 <<RT data: procedures>>=
   subroutine rt_data_write_libraries (object, unit, libpath)
     class(rt_data_t), intent(in) :: object
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: libpath
     integer :: u
     u = given_output_unit (unit)
     call object%prclib_stack%write (u, libpath)
   end subroutine rt_data_write_libraries
 
 @ %def rt_data_write_libraries
 @ Write only the beam data.
 <<RT data: rt data: TBP>>=
   procedure :: write_beams => rt_data_write_beams
 <<RT data: procedures>>=
   subroutine rt_data_write_beams (object, unit)
     class(rt_data_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer :: u
     u = given_output_unit (unit)
     call write_separator (u, 2)
     call object%beam_structure%write (u)
     call write_separator (u, 2)
   end subroutine rt_data_write_beams
 
 @ %def rt_data_write_beams
 @ Write only the process and event expressions.
 <<RT data: rt data: TBP>>=
   procedure :: write_expr => rt_data_write_expr
 <<RT data: procedures>>=
   subroutine rt_data_write_expr (object, unit)
     class(rt_data_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer :: u
     u = given_output_unit (unit)
     call write_separator (u, 2)
     call object%pn%write (u)
     call write_separator (u, 2)
   end subroutine rt_data_write_expr
 
 @ %def rt_data_write_expr
 @ Write only the process stack.
 <<RT data: rt data: TBP>>=
   procedure :: write_process_stack => rt_data_write_process_stack
 <<RT data: procedures>>=
   subroutine rt_data_write_process_stack (object, unit)
     class(rt_data_t), intent(in) :: object
     integer, intent(in), optional :: unit
     call object%process_stack%write (unit)
   end subroutine rt_data_write_process_stack
 
 @ %def rt_data_write_process_stack
 @
 <<RT data: rt data: TBP>>=
   procedure :: write_var_descriptions => rt_data_write_var_descriptions
 <<RT data: procedures>>=
   subroutine rt_data_write_var_descriptions (rt_data, unit, ascii_output)
     class(rt_data_t), intent(in) :: rt_data
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: ascii_output
     integer :: u
     logical :: ao
     u = given_output_unit (unit)
     ao = .false.;  if (present (ascii_output))  ao = ascii_output
     call rt_data%var_list%write (u, follow_link=.true., &
          descriptions=.true., ascii_output=ao)
   end subroutine rt_data_write_var_descriptions
 
 @ %def rt_data_write_var_descriptions
 @
 <<RT data: rt data: TBP>>=
   procedure :: show_description_of_string => rt_data_show_description_of_string
 <<RT data: procedures>>=
   subroutine rt_data_show_description_of_string (rt_data, string, &
          unit, ascii_output)
     class(rt_data_t), intent(in) :: rt_data
     type(string_t), intent(in) :: string
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: ascii_output
     integer :: u
     logical :: ao
     u = given_output_unit (unit)
     ao = .false.;  if (present (ascii_output))  ao = ascii_output
     call rt_data%var_list%write_var (string, unit=u, follow_link=.true., &
          defined=.false., descriptions=.true., ascii_output=ao)
   end subroutine rt_data_show_description_of_string
 
 @ %def rt_data_show_description_of_string
 @
 \subsection{Clear}
 The [[clear]] command can remove the contents of various subobjects.
 The objects themselves should stay.
 <<RT data: rt data: TBP>>=
   procedure :: clear_beams => rt_data_clear_beams
 <<RT data: procedures>>=
   subroutine rt_data_clear_beams (global)
     class(rt_data_t), intent(inout) :: global
     call global%beam_structure%final_sf ()
     call global%beam_structure%final_pol ()
     call global%beam_structure%final_mom ()
   end subroutine rt_data_clear_beams
 
 @ %def rt_data_clear_beams
 @
 \subsection{Initialization}
 Initialize runtime data.  This defines special variables such as
 [[sqrts]], and should be done only for the instance that is actually
 global.   Local copies will inherit the special variables.
 
 We link the global variable list to the process stack variable list,
 so the latter is always available (and kept global).
 <<RT data: rt data: TBP>>=
   procedure :: global_init => rt_data_global_init
 <<RT data: procedures>>=
   subroutine rt_data_global_init (global, paths, logfile)
     class(rt_data_t), intent(out), target :: global
     type(paths_t), intent(in), optional :: paths
     type(string_t), intent(in), optional :: logfile
     integer :: seed
     call global%os_data%init (paths)
     if (present (logfile)) then
        global%logfile = logfile
     else
        global%logfile = ""
     end if
     allocate (global%out_files)
     call system_clock (seed)
     call global%var_list%init_defaults (seed, paths)
     call global%init_pointer_variables ()
     call global%process_stack%init_var_list (global%var_list)
   end subroutine rt_data_global_init
 
 @ %def rt_data_global_init
 @
 \subsection{Local copies}
 This is done at compile time when a local copy of runtime data is
 needed: Link the variable list and initialize all derived parameters.
 This allows for synchronizing them with local variable changes without
 affecting global data.
 
 Also re-initialize pointer variables, so they point to local copies of
 their targets.
 <<RT data: rt data: TBP>>=
   procedure :: local_init => rt_data_local_init
 <<RT data: procedures>>=
   subroutine rt_data_local_init (local, global, env)
     class(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(in), target :: global
     integer, intent(in), optional :: env
     local%context => global
     call local%process_stack%link (global%process_stack)
     call local%process_stack%init_var_list (local%var_list)
     call local%process_stack%link_var_list (global%var_list)
     call local%var_list%append_string (var_str ("$model_name"), &
          var_str (""), intrinsic=.true.)
     call local%init_pointer_variables ()
     local%fallback_model => global%fallback_model
     local%os_data = global%os_data
     local%logfile = global%logfile
     call local%model_list%link (global%model_list)
     local%model => global%model
     if (associated (local%model)) then
        call local%model%link_var_list (local%var_list)
     end if
     if (allocated (global%event_callback)) then
        allocate (local%event_callback, source = global%event_callback)
     end if
   end subroutine rt_data_local_init
 
 @ %def rt_data_local_init
 @ These variables point to objects which get local copies:
 <<RT data: rt data: TBP>>=
   procedure :: init_pointer_variables => rt_data_init_pointer_variables
 <<RT data: procedures>>=
   subroutine rt_data_init_pointer_variables (local)
     class(rt_data_t), intent(inout), target :: local
     logical, target, save :: known = .true.
     call local%var_list%append_string_ptr (var_str ("$fc"), &
          local%os_data%fc, known, intrinsic=.true., &
          description=var_str('This string variable gives the ' // &
          '\ttt{Fortran} compiler used within \whizard. It can ' // &
          'only be accessed, not set by the user. (cf. also ' // &
          '\ttt{\$fcflags})'))
     call local%var_list%append_string_ptr (var_str ("$fcflags"), &
          local%os_data%fcflags, known, intrinsic=.true., &
          description=var_str('This string variable gives the ' // &
          'compiler flags for the \ttt{Fortran} compiler used ' // &
          'within \whizard. It can only be accessed, not set by ' // &
          'the user. (cf. also \ttt{\$fc})'))
   end subroutine rt_data_init_pointer_variables
 
 @ %def rt_data_init_pointer_variables
 @ This is done at execution time: Copy data, transfer pointers.
 [[local]] has intent(inout) because its local variable list has
 already been prepared by the previous routine.
 
 To be pedantic, the local pointers to model and library should point
 to the entries in the local copies.  (However, as long as these are
 just shallow copies with identical content, this is actually
 irrelevant.)
 
 The process library and process stacks behave as global objects.  The
 copies of the process library and process stacks should be shallow
 copies, so the contents stay identical.  Since objects may be pushed
 on the stack in the local environment, upon restoring the global
 environment, we should reverse the assignment.  Then the added stack
 elements will end up on the global stack.  (This should be
 reconsidered in a parallel environment.)
 <<RT data: rt data: TBP>>=
   procedure :: activate => rt_data_activate
 <<RT data: procedures>>=
   subroutine rt_data_activate (local)
     class(rt_data_t), intent(inout), target :: local
     class(rt_data_t), pointer :: global
     global => local%context
     if (associated (global)) then
        local%lexer => global%lexer
        call global%copy_globals (local)
        local%os_data = global%os_data
        local%logfile = global%logfile
        if (associated (global%prclib)) then
           local%prclib => &
                local%prclib_stack%get_library_ptr (global%prclib%get_name ())
        end if
        call local%import_values ()
        call local%process_stack%link (global%process_stack)
        local%it_list = global%it_list
        local%beam_structure = global%beam_structure
        local%pn = global%pn
        if (allocated (local%sample_fmt))  deallocate (local%sample_fmt)
        if (allocated (global%sample_fmt)) then
           allocate (local%sample_fmt (size (global%sample_fmt)), &
                source = global%sample_fmt)
        end if
        local%out_files => global%out_files
        local%model => global%model
        local%model_is_copy = .false.
     else if (.not. associated (local%model)) then
        local%model => local%preload_model
        local%model_is_copy = .false.
     end if
     if (associated (local%model)) then
        call local%model%link_var_list (local%var_list)
        call local%var_list%set_string (var_str ("$model_name"), &
             local%model%get_name (), is_known = .true.)
     else
        call local%var_list%set_string (var_str ("$model_name"), &
             var_str (""), is_known = .false.)
     end if
   end subroutine rt_data_activate
 
 @ %def rt_data_activate
 @ Restore the previous state of data, without actually finalizing the local
 environment.  We also clear the local process stack.  Some local modifications
 (model list and process library stack) are communicated to the global context,
 if there is any.
 
 If the [[keep_local]] flag is set, we want to retain current settings in
 the local environment.  In particular, we create an instance of the currently
 selected model (which thus becomes separated from the model library!).
 The local variables are also kept.
 <<RT data: rt data: TBP>>=
   procedure :: deactivate => rt_data_deactivate
 <<RT data: procedures>>=
   subroutine rt_data_deactivate (local, global, keep_local)
     class(rt_data_t), intent(inout), target :: local
     class(rt_data_t), intent(inout), optional, target :: global
     logical, intent(in), optional :: keep_local
     type(string_t) :: local_model, local_scheme
     logical :: same_model, delete
     delete = .true.;  if (present (keep_local))  delete = .not. keep_local
     if (present (global)) then
        if (associated (global%model) .and. associated (local%model)) then
           local_model = local%model%get_name ()
           if (global%model%has_schemes ()) then
              local_scheme = local%model%get_scheme ()
              same_model = &
                   global%model%matches (local_model, local_scheme)
           else
              same_model = global%model%matches (local_model)
           end if
        else
           same_model = .false.
        end if
        if (delete) then
           call local%process_stack%clear ()
           call local%unselect_model ()
           call local%unset_values ()
        else if (associated (local%model)) then
           call local%ensure_model_copy ()
        end if
        if (.not. same_model .and. associated (global%model)) then
           if (global%model%has_schemes ()) then
              call msg_message ("Restoring model '" // &
                   char (global%model%get_name ()) // "', scheme '" // &
                   char (global%model%get_scheme ()) // "'")
           else
              call msg_message ("Restoring model '" // &
                   char (global%model%get_name ()) // "'")
           end if
        end if
        if (associated (global%model)) then
           call global%model%link_var_list (global%var_list)
        end if
        call global%restore_globals (local)
     else
        call local%unselect_model ()
     end if
   end subroutine rt_data_deactivate
 
 @ %def rt_data_deactivate
 @ This imports the global objects for which local modifications
 should be kept.  Currently, this is only the process library stack.
 <<RT data: rt data: TBP>>=
   procedure :: copy_globals => rt_data_copy_globals
 <<RT data: procedures>>=
   subroutine rt_data_copy_globals (global, local)
     class(rt_data_t), intent(in) :: global
     class(rt_data_t), intent(inout) :: local
     local%prclib_stack = global%prclib_stack
   end subroutine rt_data_copy_globals
 
 @ %def rt_data_copy_globals
 @ This restores global objects for which local modifications
 should be kept.  May also modify (remove) the local objects.
 <<RT data: rt data: TBP>>=
   procedure :: restore_globals => rt_data_restore_globals
 <<RT data: procedures>>=
   subroutine rt_data_restore_globals (global, local)
     class(rt_data_t), intent(inout) :: global
     class(rt_data_t), intent(inout) :: local
     global%prclib_stack = local%prclib_stack
     call local%handle_exports (global)
   end subroutine rt_data_restore_globals
 
 @ %def rt_data_restore_globals
 @
 \subsection{Exported objects}
 Exported objects are transferred to the global state when a local environment
 is closed.  (For the top-level global data set, there is no effect.)
 
 The current implementation handles only the [[results]] object, which resolves
 to the local process stack.  The stack elements are appended to the global
 stack without modification, the local stack becomes empty.
 
 Write names of objects to be exported:
 <<RT data: rt data: TBP>>=
   procedure :: write_exports => rt_data_write_exports
 <<RT data: procedures>>=
   subroutine rt_data_write_exports (rt_data, unit)
     class(rt_data_t), intent(in) :: rt_data
     integer, intent(in), optional :: unit
     integer :: u, i
     u = given_output_unit (unit)
     do i = 1, rt_data%get_n_export ()
        write (u, "(A)")  char (rt_data%export(i))
     end do
   end subroutine rt_data_write_exports
 
 @ %def rt_data_write_exports
 @ The number of entries in the export list.
 <<RT data: rt data: TBP>>=
   procedure :: get_n_export => rt_data_get_n_export
 <<RT data: procedures>>=
   function rt_data_get_n_export (rt_data) result (n)
     class(rt_data_t), intent(in) :: rt_data
     integer :: n
     if (allocated (rt_data%export)) then
        n = size (rt_data%export)
     else
        n = 0
     end if
   end function rt_data_get_n_export
 
 @ %def rt_data_get_n_export
 @ Return a specific export 
 @ Append new names to the export list.  If a duplicate occurs, do not transfer
 it.
 <<RT data: rt data: TBP>>=
   procedure :: append_exports => rt_data_append_exports
 <<RT data: procedures>>=
   subroutine rt_data_append_exports (rt_data, export)
     class(rt_data_t), intent(inout) :: rt_data
     type(string_t), dimension(:), intent(in) :: export
     logical, dimension(:), allocatable :: mask
     type(string_t), dimension(:), allocatable :: tmp
     integer :: i, j, n
     if (.not. allocated (rt_data%export))  allocate (rt_data%export (0))
     n = size (rt_data%export)
     allocate (mask (size (export)), source=.false.)
     do i = 1, size (export)
        mask(i) = all (export(i) /= rt_data%export) &
             .and. all (export(i) /= export(:i-1))
     end do
     if (count (mask) > 0) then
        allocate (tmp (n + count (mask)))
        tmp(1:n) = rt_data%export(:)
        j = n
        do i = 1, size (export)
           if (mask(i)) then
              j = j + 1
              tmp(j) = export(i)
           end if
        end do
        call move_alloc (from=tmp, to=rt_data%export)
     end if
   end subroutine rt_data_append_exports
 
 @ %def rt_data_append_exports
 @ Transfer export-objects from the [[local]] rt data to the [[global]] rt
 data, as far as supported.
 <<RT data: rt data: TBP>>=
   procedure :: handle_exports => rt_data_handle_exports
 <<RT data: procedures>>=
   subroutine rt_data_handle_exports (local, global)
     class(rt_data_t), intent(inout), target :: local
     class(rt_data_t), intent(inout), target :: global
     type(string_t) :: export
     integer :: i
     if (local%get_n_export () > 0) then
        do i = 1, local%get_n_export ()
           export = local%export(i)
           select case (char (export))
           case ("results")
              call msg_message ("Exporting integration results &
                   &to outer environment")
              call local%transfer_process_stack (global)
           case default
              call msg_bug ("handle exports: '" &
                   // char (export) // "' unsupported")
           end select
        end do
     end if
   end subroutine rt_data_handle_exports
 
 @ %def rt_data_handle_exports
 @ Export the process stack.  One-by-one, take the last process from the local
 stack and push it on the global stack.  Also handle the corresponding result
 variables: append if the process did not exist yet in the global stack,
 otherwise update.
 
 TODO: result variables don't work that way yet, require initialization in the
 global variable list.
 <<RT data: rt data: TBP>>=
   procedure :: transfer_process_stack => rt_data_transfer_process_stack
 <<RT data: procedures>>=
   subroutine rt_data_transfer_process_stack (local, global)
     class(rt_data_t), intent(inout), target :: local
     class(rt_data_t), intent(inout), target :: global
     type(process_entry_t), pointer :: process
     type(string_t) :: process_id
     do
        call local%process_stack%pop_last (process)
        if (.not. associated (process))  exit
        process_id = process%get_id ()
        call global%process_stack%push (process)
        call global%process_stack%fill_result_vars (process_id)
        call global%process_stack%update_result_vars &
             (process_id, global%var_list)
     end do
   end subroutine rt_data_transfer_process_stack
     
 @ %def rt_data_transfer_process_stack
 @
 \subsection{Finalization}
 Finalizer for the variable list and the structure-function list.
 This is done only for the global RT dataset; local copies contain
 pointers to this and do not need a finalizer.
 <<RT data: rt data: TBP>>=
   procedure :: final => rt_data_global_final
 <<RT data: procedures>>=
   subroutine rt_data_global_final (global)
     class(rt_data_t), intent(inout) :: global
     call global%process_stack%final ()
     call global%prclib_stack%final ()
     call global%model_list%final ()
     call global%var_list%final (follow_link=.false.)
     if (associated (global%out_files)) then
        call file_list_final (global%out_files)
        deallocate (global%out_files)
     end if
   end subroutine rt_data_global_final
 
 @ %def rt_data_global_final
 @ The local copy needs a finalizer for the variable list, which consists
 of local copies.  This finalizer is called only when the local
 environment is finally discarded.  (Note that the process stack should
 already have been cleared after execution, which can occur many times
 for the same local environment.)
 <<RT data: rt data: TBP>>=
   procedure :: local_final => rt_data_local_final
 <<RT data: procedures>>=
   subroutine rt_data_local_final (local)
     class(rt_data_t), intent(inout) :: local
     call local%process_stack%clear ()
     call local%model_list%final ()
     call local%var_list%final (follow_link=.false.)
   end subroutine rt_data_local_final
 
 @ %def rt_data_local_final
 @
 \subsection{Model Management}
 Read a model, so it becomes available for activation.  No variables or model
 copies, this is just initialization.
 
 If this is a local environment, the model will be automatically read into the
 global context.
 <<RT data: rt data: TBP>>=
   procedure :: read_model => rt_data_read_model
 <<RT data: procedures>>=
   subroutine rt_data_read_model (global, name, model, scheme)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name
     type(string_t), intent(in), optional :: scheme
     type(model_t), pointer, intent(out) :: model
     type(string_t) :: filename
     filename = name // ".mdl"
     call global%model_list%read_model &
          (name, filename, global%os_data, model, scheme)
   end subroutine rt_data_read_model
 
 @ %def rt_data_read_model
 @ Read a UFO model.  Create it on the fly if necessary.
 <<RT data: rt data: TBP>>=
   procedure :: read_ufo_model => rt_data_read_ufo_model
 <<RT data: procedures>>=
   subroutine rt_data_read_ufo_model (global, name, model, ufo_path)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name
     type(model_t), pointer, intent(out) :: model
     type(string_t), intent(in), optional :: ufo_path
     type(string_t) :: filename
     filename = name // ".ufo.mdl"
     call global%model_list%read_model &
          (name, filename, global%os_data, model, ufo=.true., ufo_path=ufo_path)
   end subroutine rt_data_read_ufo_model
 
 @ %def rt_data_read_ufo_model
 @ Initialize the fallback model.  This model is used
 whenever the current model does not describe all physical particles
 (hadrons, mainly).  It is not supposed to be modified, and the pointer
 should remain linked to this model.
 <<RT data: rt data: TBP>>=
   procedure :: init_fallback_model => rt_data_init_fallback_model
 <<RT data: procedures>>=
   subroutine rt_data_init_fallback_model (global, name, filename)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name, filename
     call global%model_list%read_model &
          (name, filename, global%os_data, global%fallback_model)
   end subroutine rt_data_init_fallback_model
 
 @ %def rt_data_init_fallback_model
 @
 Activate a model: assign the current-model pointer and set the model name in
 the variable list.  If necessary, read the model from file.  Link the global
 variable list to the model variable list.
 <<RT data: rt data: TBP>>=
   procedure :: select_model => rt_data_select_model
 <<RT data: procedures>>=
   subroutine rt_data_select_model (global, name, scheme, ufo, ufo_path)
     class(rt_data_t), intent(inout), target :: global
     type(string_t), intent(in) :: name
     type(string_t), intent(in), optional :: scheme
     logical, intent(in), optional :: ufo
     type(string_t), intent(in), optional :: ufo_path
     logical :: same_model, ufo_model
     ufo_model = .false.;  if (present (ufo))  ufo_model = ufo
     if (associated (global%model)) then
        same_model = global%model%matches (name, scheme, ufo)
     else
        same_model = .false.
     end if
     if (.not. same_model) then
        global%model => global%model_list%get_model_ptr (name, scheme, ufo)
        if (.not. associated (global%model)) then
           if (ufo_model) then
              call global%read_ufo_model (name, global%model, ufo_path)
           else
              call global%read_model (name, global%model)
           end if
           global%model_is_copy = .false.
        else if (associated (global%context)) then
           global%model_is_copy = &
                global%model_list%model_exists (name, scheme, ufo, &
                follow_link=.false.)
        else
           global%model_is_copy = .false.
        end if
     end if
     if (associated (global%model)) then
        call global%model%link_var_list (global%var_list)
        call global%var_list%set_string (var_str ("$model_name"), &
             name, is_known = .true.)
        if (global%model%is_ufo_model ()) then
           call msg_message ("Switching to model '" // char (name) // "' " &
                // "(generated from UFO source)")
        else if (global%model%has_schemes ()) then
           call msg_message ("Switching to model '" // char (name) // "', " &
                // "scheme '" // char (global%model%get_scheme ()) // "'")
        else
           call msg_message ("Switching to model '" // char (name) // "'")
        end if
     else
        call global%var_list%set_string (var_str ("$model_name"), &
             var_str (""), is_known = .false.)
     end if
   end subroutine rt_data_select_model
 
 @ %def rt_data_select_model
 @
 Remove the model link.  Do not unset the model name variable, because
 this may unset the variable in a parent [[rt_data]] object (via linked
 var lists).
 <<RT data: rt data: TBP>>=
   procedure :: unselect_model => rt_data_unselect_model
 <<RT data: procedures>>=
   subroutine rt_data_unselect_model (global)
     class(rt_data_t), intent(inout), target :: global
     if (associated (global%model)) then
        global%model => null ()
        global%model_is_copy = .false.
     end if
   end subroutine rt_data_unselect_model
 
 @ %def rt_data_unselect_model
 @
 Create a copy of the currently selected model and append it to the local model
 list.  The model pointer is redirected to the copy.
 (Not applicable for the global model list, those models will be
 modified in-place.)
 <<RT data: rt data: TBP>>=
   procedure :: ensure_model_copy => rt_data_ensure_model_copy
 <<RT data: procedures>>=
   subroutine rt_data_ensure_model_copy (global)
     class(rt_data_t), intent(inout), target :: global
     if (associated (global%context)) then
        if (.not. global%model_is_copy) then
           call global%model_list%append_copy (global%model, global%model)
           global%model_is_copy = .true.
           call global%model%link_var_list (global%var_list)
        end if
     end if
   end subroutine rt_data_ensure_model_copy
 
 @ %def rt_data_ensure_model_copy
 @
 Modify a model variable.  The update mechanism will ensure that the model
 parameter set remains consistent.  This has to take place in a local copy
 of the current model.  If there is none yet, create one.
 <<RT data: rt data: TBP>>=
   procedure :: model_set_real => rt_data_model_set_real
 <<RT data: procedures>>=
   subroutine rt_data_model_set_real (global, name, rval, verbose, pacified)
     class(rt_data_t), intent(inout), target :: global
     type(string_t), intent(in) :: name
     real(default), intent(in) :: rval
     logical, intent(in), optional :: verbose, pacified
     call global%ensure_model_copy ()
     call global%model%set_real (name, rval, verbose, pacified)
   end subroutine rt_data_model_set_real
 
 @ %def rt_data_model_set_real
 @
 Modify particle properties.  This has to take place in a local copy
 of the current model.  If there is none yet, create one.
 <<RT data: rt data: TBP>>=
   procedure :: modify_particle => rt_data_modify_particle
 <<RT data: procedures>>=
   subroutine rt_data_modify_particle &
        (global, pdg, polarized, stable, decay, &
        isotropic_decay, diagonal_decay, decay_helicity)
     class(rt_data_t), intent(inout), target :: global
     integer, intent(in) :: pdg
     logical, intent(in), optional :: polarized, stable
     logical, intent(in), optional :: isotropic_decay, diagonal_decay
     integer, intent(in), optional :: decay_helicity
     type(string_t), dimension(:), intent(in), optional :: decay
     call global%ensure_model_copy ()
     if (present (polarized)) then
        if (polarized) then
           call global%model%set_polarized (pdg)
        else
           call global%model%set_unpolarized (pdg)
        end if
     end if
     if (present (stable)) then
        if (stable) then
           call global%model%set_stable (pdg)
        else if (present (decay)) then
           call global%model%set_unstable &
                (pdg, decay, isotropic_decay, diagonal_decay, decay_helicity)
        else
           call msg_bug ("Setting particle unstable: missing decay processes")
        end if
     end if
   end subroutine rt_data_modify_particle
 
 @ %def rt_data_modify_particle
 @
 \subsection{Managing Variables}
 Return a pointer to the currently active variable list.  If there is no model,
 this is the global variable list.  If there is one, it is the model variable
 list, which should be linked to the former.
 <<RT data: rt data: TBP>>=
   procedure :: get_var_list_ptr => rt_data_get_var_list_ptr
 <<RT data: procedures>>=
   function rt_data_get_var_list_ptr (global) result (var_list)
     class(rt_data_t), intent(in), target :: global
     type(var_list_t), pointer :: var_list
     if (associated (global%model)) then
        var_list => global%model%get_var_list_ptr ()
     else
        var_list => global%var_list
     end if
   end function rt_data_get_var_list_ptr
 
 @ %def rt_data_get_var_list_ptr
 @ Initialize a local variable: append it to the current variable list.  No
 initial value, yet.
 <<RT data: rt data: TBP>>=
   procedure :: append_log => rt_data_append_log
   procedure :: append_int => rt_data_append_int
   procedure :: append_real => rt_data_append_real
   procedure :: append_cmplx => rt_data_append_cmplx
   procedure :: append_subevt => rt_data_append_subevt
   procedure :: append_pdg_array => rt_data_append_pdg_array
   procedure :: append_string => rt_data_append_string
 <<RT data: procedures>>=
   subroutine rt_data_append_log (local, name, lval, intrinsic, user)
     class(rt_data_t), intent(inout) :: local
     type(string_t), intent(in) :: name
     logical, intent(in), optional :: lval
     logical, intent(in), optional :: intrinsic, user
     call local%var_list%append_log (name, lval, &
          intrinsic = intrinsic, user = user)
   end subroutine rt_data_append_log
 
   subroutine rt_data_append_int (local, name, ival, intrinsic, user)
     class(rt_data_t), intent(inout) :: local
     type(string_t), intent(in) :: name
     integer, intent(in), optional :: ival
     logical, intent(in), optional :: intrinsic, user
     call local%var_list%append_int (name, ival, &
          intrinsic = intrinsic, user = user)
   end subroutine rt_data_append_int
 
   subroutine rt_data_append_real (local, name, rval, intrinsic, user)
     class(rt_data_t), intent(inout) :: local
     type(string_t), intent(in) :: name
     real(default), intent(in), optional :: rval
     logical, intent(in), optional :: intrinsic, user
     call local%var_list%append_real (name, rval, &
          intrinsic = intrinsic, user = user)
   end subroutine rt_data_append_real
 
   subroutine rt_data_append_cmplx (local, name, cval, intrinsic, user)
     class(rt_data_t), intent(inout) :: local
     type(string_t), intent(in) :: name
     complex(default), intent(in), optional :: cval
     logical, intent(in), optional :: intrinsic, user
     call local%var_list%append_cmplx (name, cval, &
          intrinsic = intrinsic, user = user)
   end subroutine rt_data_append_cmplx
 
   subroutine rt_data_append_subevt (local, name, pval, intrinsic, user)
     class(rt_data_t), intent(inout) :: local
     type(string_t), intent(in) :: name
     type(subevt_t), intent(in), optional :: pval
     logical, intent(in) :: intrinsic, user
     call local%var_list%append_subevt (name, &
          intrinsic = intrinsic, user = user)
   end subroutine rt_data_append_subevt
 
   subroutine rt_data_append_pdg_array (local, name, aval, intrinsic, user)
     class(rt_data_t), intent(inout) :: local
     type(string_t), intent(in) :: name
     type(pdg_array_t), intent(in), optional :: aval
     logical, intent(in), optional :: intrinsic, user
     call local%var_list%append_pdg_array (name, aval, &
          intrinsic = intrinsic, user = user)
   end subroutine rt_data_append_pdg_array
 
   subroutine rt_data_append_string (local, name, sval, intrinsic, user)
     class(rt_data_t), intent(inout) :: local
     type(string_t), intent(in) :: name
     type(string_t), intent(in), optional :: sval
     logical, intent(in), optional :: intrinsic, user
     call local%var_list%append_string (name, sval, &
          intrinsic = intrinsic, user = user)
   end subroutine rt_data_append_string
 
 @ %def rt_data_append_log
 @ %def rt_data_append_int
 @ %def rt_data_append_real
 @ %def rt_data_append_cmplx
 @ %def rt_data_append_subevt
 @ %def rt_data_append_pdg_array
 @ %def rt_data_append_string
 @ Import values for all local variables, given a global context environment
 where these variables are defined.
 <<RT data: rt data: TBP>>=
   procedure :: import_values => rt_data_import_values
 <<RT data: procedures>>=
   subroutine rt_data_import_values (local)
     class(rt_data_t), intent(inout) :: local
     type(rt_data_t), pointer :: global
     global => local%context
     if (associated (global)) then
        call local%var_list%import (global%var_list)
     end if
   end subroutine rt_data_import_values
 
 @ %def rt_data_import_values
 @ Unset all variable values.
 <<RT data: rt data: TBP>>=
   procedure :: unset_values => rt_data_unset_values
 <<RT data: procedures>>=
   subroutine rt_data_unset_values (global)
     class(rt_data_t), intent(inout) :: global
     call global%var_list%undefine (follow_link=.false.)
   end subroutine rt_data_unset_values
 
 @ %def rt_data_unset_values
 @ Set a variable.  (Not a model variable, these are handled separately.)  We
 can assume that the variable has been initialized.
 <<RT data: rt data: TBP>>=
   procedure :: set_log => rt_data_set_log
   procedure :: set_int => rt_data_set_int
   procedure :: set_real => rt_data_set_real
   procedure :: set_cmplx => rt_data_set_cmplx
   procedure :: set_subevt => rt_data_set_subevt
   procedure :: set_pdg_array => rt_data_set_pdg_array
   procedure :: set_string => rt_data_set_string
 <<RT data: procedures>>=
   subroutine rt_data_set_log &
        (global, name, lval, is_known, force, verbose)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name
     logical, intent(in) :: lval
     logical, intent(in) :: is_known
     logical, intent(in), optional :: force, verbose
     call global%var_list%set_log (name, lval, is_known, &
          force=force, verbose=verbose)
   end subroutine rt_data_set_log
 
   subroutine rt_data_set_int &
        (global, name, ival, is_known, force, verbose)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name
     integer, intent(in) :: ival
     logical, intent(in) :: is_known
     logical, intent(in), optional :: force, verbose
     call global%var_list%set_int (name, ival, is_known, &
          force=force, verbose=verbose)
   end subroutine rt_data_set_int
 
   subroutine rt_data_set_real &
        (global, name, rval, is_known, force, verbose, pacified)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name
     real(default), intent(in) :: rval
     logical, intent(in) :: is_known
     logical, intent(in), optional :: force, verbose, pacified
     call global%var_list%set_real (name, rval, is_known, &
          force=force, verbose=verbose, pacified=pacified)
   end subroutine rt_data_set_real
 
   subroutine rt_data_set_cmplx &
        (global, name, cval, is_known, force, verbose, pacified)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name
     complex(default), intent(in) :: cval
     logical, intent(in) :: is_known
     logical, intent(in), optional :: force, verbose, pacified
     call global%var_list%set_cmplx (name, cval, is_known, &
          force=force, verbose=verbose, pacified=pacified)
   end subroutine rt_data_set_cmplx
 
   subroutine rt_data_set_subevt &
        (global, name, pval, is_known, force, verbose)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name
     type(subevt_t), intent(in) :: pval
     logical, intent(in) :: is_known
     logical, intent(in), optional :: force, verbose
     call global%var_list%set_subevt (name, pval, is_known, &
          force=force, verbose=verbose)
   end subroutine rt_data_set_subevt
 
   subroutine rt_data_set_pdg_array &
        (global, name, aval, is_known, force, verbose)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name
     type(pdg_array_t), intent(in) :: aval
     logical, intent(in) :: is_known
     logical, intent(in), optional :: force, verbose
     call global%var_list%set_pdg_array (name, aval, is_known, &
          force=force, verbose=verbose)
   end subroutine rt_data_set_pdg_array
 
   subroutine rt_data_set_string &
        (global, name, sval, is_known, force, verbose)
     class(rt_data_t), intent(inout) :: global
     type(string_t), intent(in) :: name
     type(string_t), intent(in) :: sval
     logical, intent(in) :: is_known
     logical, intent(in), optional :: force, verbose
     call global%var_list%set_string (name, sval, is_known, &
          force=force, verbose=verbose)
   end subroutine rt_data_set_string
 
 @ %def rt_data_set_log
 @ %def rt_data_set_int
 @ %def rt_data_set_real
 @ %def rt_data_set_cmplx
 @ %def rt_data_set_subevt
 @ %def rt_data_set_pdg_array
 @ %def rt_data_set_string
 @ Return the value of a variable, assuming that the type is correct.
 <<RT data: rt data: TBP>>=
   procedure :: get_lval => rt_data_get_lval
   procedure :: get_ival => rt_data_get_ival
   procedure :: get_rval => rt_data_get_rval
   procedure :: get_cval => rt_data_get_cval
   procedure :: get_pval => rt_data_get_pval
   procedure :: get_aval => rt_data_get_aval
   procedure :: get_sval => rt_data_get_sval
 <<RT data: procedures>>=
   function rt_data_get_lval (global, name) result (lval)
     logical :: lval
     class(rt_data_t), intent(in), target :: global
     type(string_t), intent(in) :: name
     type(var_list_t), pointer :: var_list
     var_list => global%get_var_list_ptr ()
     lval = var_list%get_lval (name)
   end function rt_data_get_lval
 
   function rt_data_get_ival (global, name) result (ival)
     integer :: ival
     class(rt_data_t), intent(in), target :: global
     type(string_t), intent(in) :: name
     type(var_list_t), pointer :: var_list
     var_list => global%get_var_list_ptr ()
     ival = var_list%get_ival (name)
   end function rt_data_get_ival
 
   function rt_data_get_rval (global, name) result (rval)
     real(default) :: rval
     class(rt_data_t), intent(in), target :: global
     type(string_t), intent(in) :: name
     type(var_list_t), pointer :: var_list
     var_list => global%get_var_list_ptr ()
     rval = var_list%get_rval (name)
   end function rt_data_get_rval
 
   function rt_data_get_cval (global, name) result (cval)
     complex(default) :: cval
     class(rt_data_t), intent(in), target :: global
     type(string_t), intent(in) :: name
     type(var_list_t), pointer :: var_list
     var_list => global%get_var_list_ptr ()
     cval = var_list%get_cval (name)
   end function rt_data_get_cval
 
   function rt_data_get_aval (global, name) result (aval)
     type(pdg_array_t) :: aval
     class(rt_data_t), intent(in), target :: global
     type(string_t), intent(in) :: name
     type(var_list_t), pointer :: var_list
     var_list => global%get_var_list_ptr ()
     aval = var_list%get_aval (name)
   end function rt_data_get_aval
 
   function rt_data_get_pval (global, name) result (pval)
     type(subevt_t) :: pval
     class(rt_data_t), intent(in), target :: global
     type(string_t), intent(in) :: name
     type(var_list_t), pointer :: var_list
     var_list => global%get_var_list_ptr ()
     pval = var_list%get_pval (name)
   end function rt_data_get_pval
 
   function rt_data_get_sval (global, name) result (sval)
     type(string_t) :: sval
     class(rt_data_t), intent(in), target :: global
     type(string_t), intent(in) :: name
     type(var_list_t), pointer :: var_list
     var_list => global%get_var_list_ptr ()
     sval = var_list%get_sval (name)
   end function rt_data_get_sval
 
 @ %def rt_data_get_lval
 @ %def rt_data_get_ival
 @ %def rt_data_get_rval
 @ %def rt_data_get_cval
 @ %def rt_data_get_pval
 @ %def rt_data_get_aval
 @ %def rt_data_get_sval
 @ Return true if the variable exists in the global list.
 <<RT data: rt data: TBP>>=
   procedure :: contains => rt_data_contains
 <<RT data: procedures>>=
   function rt_data_contains (global, name) result (lval)
     logical :: lval
     class(rt_data_t), intent(in) :: global
     type(string_t), intent(in) :: name
     type(var_list_t), pointer :: var_list
     var_list => global%get_var_list_ptr ()
     lval = var_list%contains (name)
   end function rt_data_contains
 
 @ %def rt_data_contains
 @
 \subsection{Further Content}
 Add a library (available via a pointer of type [[prclib_entry_t]]) to
 the stack and update the pointer and variable list to the current
 library.  The pointer association of [[prclib_entry]] will be discarded.
 <<RT data: rt data: TBP>>=
   procedure :: add_prclib => rt_data_add_prclib
 <<RT data: procedures>>=
   subroutine rt_data_add_prclib (global, prclib_entry)
     class(rt_data_t), intent(inout) :: global
     type(prclib_entry_t), intent(inout), pointer :: prclib_entry
     call global%prclib_stack%push (prclib_entry)
     call global%update_prclib (global%prclib_stack%get_first_ptr ())
   end subroutine rt_data_add_prclib
 
 @ %def rt_data_add_prclib
 @ Given a pointer to a process library, make this the currently active
 library.
 <<RT data: rt data: TBP>>=
   procedure :: update_prclib => rt_data_update_prclib
 <<RT data: procedures>>=
   subroutine rt_data_update_prclib (global, lib)
     class(rt_data_t), intent(inout) :: global
     type(process_library_t), intent(in), target :: lib
     global%prclib => lib
     if (global%var_list%contains (&
          var_str ("$library_name"), follow_link = .false.)) then
        call global%var_list%set_string (var_str ("$library_name"), &
             global%prclib%get_name (), is_known=.true.)
     else
        call global%var_list%append_string ( &
             var_str ("$library_name"), global%prclib%get_name (), &
             intrinsic = .true.)
     end if
   end subroutine rt_data_update_prclib
 
 @ %def rt_data_update_prclib
 @
 \subsection{Miscellaneous}
 The helicity selection data are distributed among several parameters.  Here,
 we collect them in a single record.
 <<RT data: rt data: TBP>>=
   procedure :: get_helicity_selection => rt_data_get_helicity_selection
 <<RT data: procedures>>=
   function rt_data_get_helicity_selection (rt_data) result (helicity_selection)
     class(rt_data_t), intent(in) :: rt_data
     type(helicity_selection_t) :: helicity_selection
     associate (var_list => rt_data%var_list)
       helicity_selection%active = var_list%get_lval (&
            var_str ("?helicity_selection_active"))
       if (helicity_selection%active) then
          helicity_selection%threshold = var_list%get_rval (&
               var_str ("helicity_selection_threshold"))
          helicity_selection%cutoff = var_list%get_ival (&
               var_str ("helicity_selection_cutoff"))
       end if
     end associate
   end function rt_data_get_helicity_selection
 
 @ %def rt_data_get_helicity_selection
 @ Show the beam setup: beam structure and relevant global variables.
 <<RT data: rt data: TBP>>=
   procedure :: show_beams => rt_data_show_beams
 <<RT data: procedures>>=
   subroutine rt_data_show_beams (rt_data, unit)
     class(rt_data_t), intent(in) :: rt_data
     integer, intent(in), optional :: unit
     type(string_t) :: s
     integer :: u
     u = given_output_unit (unit)
     associate (beams => rt_data%beam_structure, var_list => rt_data%var_list)
       call beams%write (u)
       if (.not. beams%asymmetric () .and. beams%get_n_beam () == 2) then
          write (u, "(2x,A," // FMT_19 // ",1x,'GeV')") "sqrts =", &
               var_list%get_rval (var_str ("sqrts"))
       end if
       if (beams%contains ("pdf_builtin")) then
          s = var_list%get_sval (var_str ("$pdf_builtin_set"))
          if (s /= "") then
             write (u, "(2x,A,1x,3A)")  "PDF set =", '"', char (s), '"'
          else
             write (u, "(2x,A,1x,A)")  "PDF set =", "[undefined]"
          end if
       end if
       if (beams%contains ("lhapdf")) then
          s = var_list%get_sval (var_str ("$lhapdf_dir"))
          if (s /= "") then
             write (u, "(2x,A,1x,3A)")  "LHAPDF dir    =", '"', char (s), '"'
          end if
          s = var_list%get_sval (var_str ("$lhapdf_file"))
          if (s /= "") then
             write (u, "(2x,A,1x,3A)")  "LHAPDF file   =", '"', char (s), '"'
             write (u, "(2x,A,1x,I0)") "LHAPDF member =", &
                  var_list%get_ival (var_str ("lhapdf_member"))
          else
             write (u, "(2x,A,1x,A)")  "LHAPDF file   =", "[undefined]"
          end if
       end if
       if (beams%contains ("lhapdf_photon")) then
          s = var_list%get_sval (var_str ("$lhapdf_dir"))
          if (s /= "") then
             write (u, "(2x,A,1x,3A)")  "LHAPDF dir    =", '"', char (s), '"'
          end if
          s = var_list%get_sval (var_str ("$lhapdf_photon_file"))
          if (s /= "") then
             write (u, "(2x,A,1x,3A)")  "LHAPDF file   =", '"', char (s), '"'
             write (u, "(2x,A,1x,I0)") "LHAPDF member =", &
                  var_list%get_ival (var_str ("lhapdf_member"))
             write (u, "(2x,A,1x,I0)") "LHAPDF scheme =", &
                  var_list%get_ival (&
                  var_str ("lhapdf_photon_scheme"))
          else
             write (u, "(2x,A,1x,A)")  "LHAPDF file   =", "[undefined]"
          end if
       end if
       if (beams%contains ("isr")) then
          write (u, "(2x,A," // FMT_19 // ")") "ISR alpha        =", &
               var_list%get_rval (var_str ("isr_alpha"))
          write (u, "(2x,A," // FMT_19 // ")") "ISR Q max        =", &
               var_list%get_rval (var_str ("isr_q_max"))
          write (u, "(2x,A," // FMT_19 // ")") "ISR mass         =", &
               var_list%get_rval (var_str ("isr_mass"))
          write (u, "(2x,A,1x,I0)") "ISR order        =", &
               var_list%get_ival (var_str ("isr_order"))
          write (u, "(2x,A,1x,L1)") "ISR recoil       =", &
               var_list%get_lval (var_str ("?isr_recoil"))
          write (u, "(2x,A,1x,L1)") "ISR energy cons. =", &
               var_list%get_lval (var_str ("?isr_keep_energy"))
       end if
       if (beams%contains ("epa")) then
          write (u, "(2x,A," // FMT_19 // ")") "EPA alpha         =", &
               var_list%get_rval (var_str ("epa_alpha"))
          write (u, "(2x,A," // FMT_19 // ")") "EPA x min         =", &
               var_list%get_rval (var_str ("epa_x_min"))
          write (u, "(2x,A," // FMT_19 // ")") "EPA Q min         =", &
               var_list%get_rval (var_str ("epa_q_min"))
          write (u, "(2x,A," // FMT_19 // ")") "EPA E max         =", &
               var_list%get_rval (var_str ("epa_e_max"))
          write (u, "(2x,A," // FMT_19 // ")") "EPA mass          =", &
               var_list%get_rval (var_str ("epa_mass"))
          write (u, "(2x,A,1x,L1)") "EPA recoil        =", &
               var_list%get_lval (var_str ("?epa_recoil"))
          write (u, "(2x,A,1x,L1)") "EPA  energy cons. =", &
               var_list%get_lval (var_str ("?epa_keep_energy"))
       end if
       if (beams%contains ("ewa")) then
          write (u, "(2x,A," // FMT_19 // ")") "EWA x min       =", &
               var_list%get_rval (var_str ("ewa_x_min"))
          write (u, "(2x,A," // FMT_19 // ")") "EWA Pt max      =", &
               var_list%get_rval (var_str ("ewa_pt_max"))
          write (u, "(2x,A," // FMT_19 // ")") "EWA mass        =", &
               var_list%get_rval (var_str ("ewa_mass"))
          write (u, "(2x,A,1x,L1)") "EWA recoil       =", &
               var_list%get_lval (var_str ("?ewa_recoil"))
          write (u, "(2x,A,1x,L1)") "EWA energy cons. =", &
               var_list%get_lval (var_str ("ewa_keep_energy"))
       end if
       if (beams%contains ("circe1")) then
          write (u, "(2x,A,1x,I0)") "CIRCE1 version    =", &
               var_list%get_ival (var_str ("circe1_ver"))
          write (u, "(2x,A,1x,I0)") "CIRCE1 revision   =", &
               var_list%get_ival (var_str ("circe1_rev"))
          s = var_list%get_sval (var_str ("$circe1_acc"))
          write (u, "(2x,A,1x,A)") "CIRCE1 acceler.   =", char (s)
          write (u, "(2x,A,1x,I0)") "CIRCE1 chattin.   =", &
               var_list%get_ival (var_str ("circe1_chat"))
          write (u, "(2x,A," // FMT_19 // ")") "CIRCE1 sqrts      =", &
               var_list%get_rval (var_str ("circe1_sqrts"))
          write (u, "(2x,A," // FMT_19 // ")") "CIRCE1 epsil.     =", &
               var_list%get_rval (var_str ("circe1_eps"))
          write (u, "(2x,A,1x,L1)") "CIRCE1 phot. 1  =", &
               var_list%get_lval (var_str ("?circe1_photon1"))
          write (u, "(2x,A,1x,L1)") "CIRCE1 phot. 2  =", &
               var_list%get_lval (var_str ("?circe1_photon2"))
          write (u, "(2x,A,1x,L1)") "CIRCE1 generat. =", &
               var_list%get_lval (var_str ("?circe1_generate"))
          write (u, "(2x,A,1x,L1)") "CIRCE1 mapping  =", &
               var_list%get_lval (var_str ("?circe1_map"))
          write (u, "(2x,A," // FMT_19 // ")") "CIRCE1 map. slope =", &
               var_list%get_rval (var_str ("circe1_mapping_slope"))
          write (u, "(2x,A,1x,L1)") "CIRCE recoil photon =", &
               var_list%get_lval (var_str ("?circe1_with_radiation"))
       end if
       if (beams%contains ("circe2")) then
          s = var_list%get_sval (var_str ("$circe2_design"))
          write (u, "(2x,A,1x,A)") "CIRCE2 design   =", char (s)
          s = var_list%get_sval (var_str ("$circe2_file"))
          write (u, "(2x,A,1x,A)") "CIRCE2 file     =", char (s)
          write (u, "(2x,A,1x,L1)") "CIRCE2 polarized =", &
               var_list%get_lval (var_str ("?circe2_polarized"))
       end if
       if (beams%contains ("gaussian")) then
          write (u, "(2x,A,1x," // FMT_12 // ")") "Gaussian spread 1    =", &
               var_list%get_rval (var_str ("gaussian_spread1"))
          write (u, "(2x,A,1x," // FMT_12 // ")") "Gaussian spread 2    =", &
               var_list%get_rval (var_str ("gaussian_spread2"))
       end if
       if (beams%contains ("beam_events")) then
          s = var_list%get_sval (var_str ("$beam_events_file"))
          write (u, "(2x,A,1x,A)") "Beam events file     =", char (s)
          write (u, "(2x,A,1x,L1)") "Beam events EOF warn =", &
               var_list%get_lval (var_str ("?beam_events_warn_eof"))
       end if
     end associate
   end subroutine rt_data_show_beams
 
 @ %def rt_data_show_beams
 @ Return the collision energy as determined by the current beam
 settings.  Without beam setup, this is the [[sqrts]] variable.
 
 If the value is meaningless for a setup, the function returns zero.
 <<RT data: rt data: TBP>>=
   procedure :: get_sqrts => rt_data_get_sqrts
 <<RT data: procedures>>=
   function rt_data_get_sqrts (rt_data) result (sqrts)
     class(rt_data_t), intent(in) :: rt_data
     real(default) :: sqrts
     sqrts = rt_data%var_list%get_rval (var_str ("sqrts"))
   end function rt_data_get_sqrts
 
 @ %def rt_data_get_sqrts
 @ For testing purposes, the [[rt_data_t]] contents can be pacified to
 suppress numerical fluctuations in (constant) test matrix elements.
 <<RT data: rt data: TBP>>=
   procedure :: pacify => rt_data_pacify
 <<RT data: procedures>>=
   subroutine rt_data_pacify (rt_data, efficiency_reset, error_reset)
     class(rt_data_t), intent(inout) :: rt_data
     logical, intent(in), optional :: efficiency_reset, error_reset
     type(process_entry_t), pointer :: process
     process => rt_data%process_stack%first
     do while (associated (process))
        call process%pacify (efficiency_reset, error_reset)
        process => process%next
     end do
   end subroutine rt_data_pacify
 
 @ %def rt_data_pacify
 @
 <<RT data: rt data: TBP>>=
   procedure :: set_event_callback => rt_data_set_event_callback
 <<RT data: procedures>>=
   subroutine rt_data_set_event_callback (global, callback)
     class(rt_data_t), intent(inout) :: global
     class(event_callback_t), intent(in) :: callback
     if (allocated (global%event_callback))  deallocate (global%event_callback)
     allocate (global%event_callback, source = callback)
   end subroutine rt_data_set_event_callback
 
 @ %def rt_data_set_event_callback
 @
 <<RT data: rt data: TBP>>=
   procedure :: has_event_callback => rt_data_has_event_callback
   procedure :: get_event_callback => rt_data_get_event_callback
 <<RT data: procedures>>=
   function rt_data_has_event_callback (global) result (flag)
     class(rt_data_t), intent(in) :: global
     logical :: flag
     flag = allocated (global%event_callback)
   end function rt_data_has_event_callback
 
   function rt_data_get_event_callback (global) result (callback)
     class(rt_data_t), intent(in) :: global
     class(event_callback_t), allocatable :: callback
     if (allocated (global%event_callback)) then
        allocate (callback, source = global%event_callback)
     end if
   end function rt_data_get_event_callback
 
 @ %def rt_data_has_event_callback
 @ %def rt_data_get_event_callback
 @ Force system-dependent objects to well-defined values.  Some of the
 variables are locked and therefore must be addressed directly.
 
 This is, of course, only required for testing purposes. In principle,
 the [[real_specimen]] variables could be set to their values in
 [[rt_data_t]], but this depends on the precision again, so we set
 them to some dummy values.
 <<RT data: public>>=
   public :: fix_system_dependencies
 <<RT data: procedures>>=
   subroutine fix_system_dependencies (global)
     class(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
 
     var_list => global%get_var_list_ptr ()
     call var_list%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true., force=.true.)
     call var_list%set_log (var_str ("?openmp_is_active"), &
          .false., is_known = .true., force=.true.)
     call var_list%set_int (var_str ("openmp_num_threads_default"), &
          1, is_known = .true., force=.true.)
     call var_list%set_int (var_str ("openmp_num_threads"), &
          1, is_known = .true., force=.true.)
     call var_list%set_int (var_str ("real_range"), &
          307, is_known = .true., force=.true.)
     call var_list%set_int (var_str ("real_precision"), &
          15, is_known = .true., force=.true.)
     call var_list%set_real (var_str ("real_epsilon"), &
          1.e-16_default, is_known = .true., force=.true.)
     call var_list%set_real (var_str ("real_tiny"), &
          1.e-300_default, is_known = .true., force=.true.)
 
     global%os_data%fc = "Fortran-compiler"
     global%os_data%fcflags = "Fortran-flags"
 
   end subroutine fix_system_dependencies
 
 @ %def fix_system_dependencies
 @
 <<RT data: public>>=
   public :: show_description_of_string
 <<RT data: procedures>>=
   subroutine show_description_of_string (string)
     type(string_t), intent(in) :: string
     type(rt_data_t), target :: global
     call global%global_init ()
     call global%show_description_of_string (string, ascii_output=.true.)
   end subroutine show_description_of_string
 
 @ %def show_description_of_string
 @
 <<RT data: public>>=
   public :: show_tex_descriptions
 <<RT data: procedures>>=
   subroutine show_tex_descriptions ()
     type(rt_data_t), target :: global
     call global%global_init ()
     call fix_system_dependencies (global)
     call global%set_int (var_str ("seed"), 0, is_known=.true.)
     call global%var_list%sort ()
     call global%write_var_descriptions ()
   end subroutine show_tex_descriptions
 
 @ %def show_tex_descriptions
 @
 \subsection{Unit Tests}
 Test module, followed by the corresponding implementation module.
 <<[[rt_data_ut.f90]]>>=
 <<File header>>
 
 module rt_data_ut
   use unit_tests
   use rt_data_uti
 
 <<Standard module head>>
 
 <<RT data: public test>>
 
 contains
 
 <<RT data: test driver>>
 
 end module rt_data_ut
 @ %def rt_data_ut
 @
 <<[[rt_data_uti.f90]]>>=
 <<File header>>
 
 module rt_data_uti
 
 <<Use kinds>>
 <<Use strings>>
   use format_defs, only: FMT_19
   use ifiles
   use lexers
   use parser
   use flavors
   use variables, only: var_list_t, var_entry_t, var_entry_init_int
   use eval_trees
   use models
   use prclib_stacks
 
   use rt_data
 
 <<Standard module head>>
 
 <<RT data: test declarations>>
 
 contains
 
 <<RT data: test auxiliary>>
 
 <<RT data: tests>>
 
 end module rt_data_uti
 @ %def rt_data_ut
 @ API: driver for the unit tests below.
 <<RT data: public test>>=
   public :: rt_data_test
 <<RT data: test driver>>=
   subroutine rt_data_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<RT data: execute tests>>
   end subroutine rt_data_test
 
 @ %def rt_data_test
 @
 \subsubsection{Initial content}
 @
 Display the RT data in the state just after (global) initialization.
 <<RT data: execute tests>>=
   call test (rt_data_1, "rt_data_1", &
        "initialize", &
        u, results)
 <<RT data: test declarations>>=
   public :: rt_data_1
 <<RT data: tests>>=
   subroutine rt_data_1 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: rt_data_1"
     write (u, "(A)")  "*   Purpose: initialize global runtime data"
     write (u, "(A)")
 
     call global%global_init (logfile = var_str ("rt_data.log"))
     call fix_system_dependencies (global)
 
     call global%set_int (var_str ("seed"), 0, is_known=.true.)
 
     call global%it_list%init ([2, 3], [5000, 20000])
 
     call global%write (u)
 
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_1"
 
   end subroutine rt_data_1
 
 @ %def rt_data_1
 @
 \subsubsection{Fill values}
 Fill in empty slots in the runtime data block.
 <<RT data: execute tests>>=
   call test (rt_data_2, "rt_data_2", &
        "fill", &
        u, results)
 <<RT data: test declarations>>=
   public :: rt_data_2
 <<RT data: tests>>=
   subroutine rt_data_2 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     type(flavor_t), dimension(2) :: flv
     type(string_t) :: cut_expr_text
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: parse_tree
 
     write (u, "(A)")  "* Test output: rt_data_2"
     write (u, "(A)")  "*   Purpose: initialize global runtime data &
          &and fill contents"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call fix_system_dependencies (global)
 
     call global%select_model (var_str ("Test"))
 
     call global%set_real (var_str ("sqrts"), &
          1000._default, is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
     call flv%init ([25,25], global%model)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("run1"), is_known = .true.)
     call global%set_real (var_str ("luminosity"), &
          33._default, is_known = .true.)
 
     call syntax_pexpr_init ()
     cut_expr_text = "all Pt > 100 [s]"
     call ifile_append (ifile, cut_expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_lexpr (parse_tree, stream, .true.)
     global%pn%cuts_lexpr => parse_tree%get_root_ptr ()
 
     allocate (global%sample_fmt (2))
     global%sample_fmt(1) = "foo_fmt"
     global%sample_fmt(2) = "bar_fmt"
 
     call global%write (u)
 
     call parse_tree_final (parse_tree)
     call stream_final (stream)
     call ifile_final (ifile)
     call syntax_pexpr_final ()
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_2"
 
   end subroutine rt_data_2
 
 @ %def rt_data_2
 @
 \subsubsection{Save and restore}
 Set up a local runtime data block, change some contents, restore the
 global block.
 <<RT data: execute tests>>=
   call test (rt_data_3, "rt_data_3", &
        "save/restore", &
        u, results)
 <<RT data: test declarations>>=
   public :: rt_data_3
 <<RT data: tests>>=
   subroutine rt_data_3 (u)
     use event_base, only: event_callback_nop_t
     integer, intent(in) :: u
     type(rt_data_t), target :: global, local
     type(flavor_t), dimension(2) :: flv
     type(string_t) :: cut_expr_text
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: parse_tree
     type(prclib_entry_t), pointer :: lib
     type(event_callback_nop_t) :: event_callback_nop
 
     write (u, "(A)")  "* Test output: rt_data_3"
     write (u, "(A)")  "*   Purpose: initialize global runtime data &
          &and fill contents;"
     write (u, "(A)")  "*            copy to local block and back"
     write (u, "(A)")
 
     write (u, "(A)")  "* Init global data"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call fix_system_dependencies (global)
 
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%select_model (var_str ("Test"))
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call flv%init ([25,25], global%model)
 
     call global%beam_structure%init_sf (flv%get_name (), [1])
     call global%beam_structure%set_sf (1, 1, var_str ("pdf_builtin"))
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("run1"), is_known = .true.)
     call global%set_real (var_str ("luminosity"), &
          33._default, is_known = .true.)
 
     call syntax_pexpr_init ()
     cut_expr_text = "all Pt > 100 [s]"
     call ifile_append (ifile, cut_expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_lexpr (parse_tree, stream, .true.)
     global%pn%cuts_lexpr => parse_tree%get_root_ptr ()
 
     allocate (global%sample_fmt (2))
     global%sample_fmt(1) = "foo_fmt"
     global%sample_fmt(2) = "bar_fmt"
 
     allocate (lib)
     call lib%init (var_str ("library_1"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "* Init and modify local data"
     write (u, "(A)")
 
     call local%local_init (global)
     call local%append_string (var_str ("$integration_method"), intrinsic=.true.)
     call local%append_string (var_str ("$phs_method"), intrinsic=.true.)
 
     call local%activate ()
 
     write (u, "(1x,A,L1)")  "model associated   = ", associated (local%model)
     write (u, "(1x,A,L1)")  "library associated = ", associated (local%prclib)
     write (u, *)
 
     call local%model_set_real (var_str ("ms"), 150._default)
     call local%set_string (var_str ("$integration_method"), &
          var_str ("midpoint"), is_known = .true.)
     call local%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
 
     local%os_data%fc = "Local compiler"
 
     allocate (lib)
     call lib%init (var_str ("library_2"))
     call local%add_prclib (lib)
 
     call local%set_event_callback (event_callback_nop)
 
     call local%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Restore global data"
     write (u, "(A)")
 
     call local%deactivate (global)
 
     write (u, "(1x,A,L1)")  "model associated   = ", associated (global%model)
     write (u, "(1x,A,L1)")  "library associated = ", associated (global%prclib)
     write (u, *)
 
     call global%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call parse_tree_final (parse_tree)
     call stream_final (stream)
     call ifile_final (ifile)
     call syntax_pexpr_final ()
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_3"
 
   end subroutine rt_data_3
 
 @ %def rt_data_3
 @
 \subsubsection{Show variables}
 Display selected variables in the global record.
 <<RT data: execute tests>>=
   call test (rt_data_4, "rt_data_4", &
        "show variables", &
        u, results)
 <<RT data: test declarations>>=
   public :: rt_data_4
 <<RT data: tests>>=
   subroutine rt_data_4 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
 
     type(string_t), dimension(0) :: empty_string_array
 
     write (u, "(A)")  "* Test output: rt_data_4"
     write (u, "(A)")  "*   Purpose: display selected variables"
     write (u, "(A)")
 
     call global%global_init ()
 
     write (u, "(A)")  "* No variables:"
     write (u, "(A)")
 
     call global%write_vars (u, empty_string_array)
 
     write (u, "(A)")  "* Two variables:"
     write (u, "(A)")
 
     call global%write_vars (u, &
          [var_str ("?unweighted"), var_str ("$phs_method")])
 
     write (u, "(A)")
     write (u, "(A)")  "* Display whole record with selected variables"
     write (u, "(A)")
 
     call global%write (u, &
          vars = [var_str ("?unweighted"), var_str ("$phs_method")])
 
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_4"
 
   end subroutine rt_data_4
 
 @ %def rt_data_4
 @
 \subsubsection{Show parts}
 Display only selected parts in the state just after (global) initialization.
 <<RT data: execute tests>>=
   call test (rt_data_5, "rt_data_5", &
        "show parts", &
        u, results)
 <<RT data: test declarations>>=
   public :: rt_data_5
 <<RT data: tests>>=
   subroutine rt_data_5 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: rt_data_5"
     write (u, "(A)")  "*   Purpose: display parts of rt data"
     write (u, "(A)")
 
     call global%global_init ()
     call global%write_libraries (u)
 
     write (u, "(A)")
 
     call global%write_beams (u)
 
     write (u, "(A)")
 
     call global%write_process_stack (u)
 
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_5"
 
   end subroutine rt_data_5
 
 @ %def rt_data_5
 @
 \subsubsection{Local Model}
 Locally modify a model and restore the global one.  We need an auxiliary
 function to determine the status of a model particle:
 <<RT data: test auxiliary>>=
   function is_stable (pdg, global) result (flag)
     integer, intent(in) :: pdg
     type(rt_data_t), intent(in) :: global
     logical :: flag
     type(flavor_t) :: flv
     call flv%init (pdg, global%model)
     flag = flv%is_stable ()
   end function is_stable
 
   function is_polarized (pdg, global) result (flag)
     integer, intent(in) :: pdg
     type(rt_data_t), intent(in) :: global
     logical :: flag
     type(flavor_t) :: flv
     call flv%init (pdg, global%model)
     flag = flv%is_polarized ()
   end function is_polarized
 
 @ %def is_stable is_polarized
 <<RT data: execute tests>>=
   call test (rt_data_6, "rt_data_6", &
        "local model", &
        u, results)
 <<RT data: test declarations>>=
   public :: rt_data_6
 <<RT data: tests>>=
   subroutine rt_data_6 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global, local
     type(var_list_t), pointer :: model_vars
     type(string_t) :: var_name
 
     write (u, "(A)")  "* Test output: rt_data_6"
     write (u, "(A)")  "*   Purpose: apply and keep local modifications to model"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%select_model (var_str ("Test"))
 
     write (u, "(A)")  "* Original model"
     write (u, "(A)")
 
     call global%write_model_list (u)
     write (u, *)
     write (u, "(A,L1)")  "s is stable    = ", is_stable (25, global)
     write (u, "(A,L1)")  "f is polarized = ", is_polarized (6, global)
 
     write (u, *)
 
     var_name = "ff"
 
     write (u, "(A)", advance="no")  "Global model variable: "
     model_vars => global%model%get_var_list_ptr ()
     call model_vars%write_var (var_name, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Apply local modifications: unstable"
     write (u, "(A)")
 
     call local%local_init (global)
     call local%activate ()
 
     call local%model_set_real (var_name, 0.4_default)
     call local%modify_particle (25, stable = .false., decay = [var_str ("d1")])
     call local%modify_particle (6, stable = .false., &
          decay = [var_str ("f1")], isotropic_decay = .true.)
     call local%modify_particle (-6, stable = .false., &
          decay = [var_str ("f2"), var_str ("f3")], diagonal_decay = .true.)
 
     call local%model%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Further modifications"
     write (u, "(A)")
 
     call local%modify_particle (6, stable = .false., &
          decay = [var_str ("f1")], &
          diagonal_decay = .true., isotropic_decay = .false.)
     call local%modify_particle (-6, stable = .false., &
          decay = [var_str ("f2"), var_str ("f3")], &
          diagonal_decay = .false., isotropic_decay = .true.)
     call local%model%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Further modifications: f stable but polarized"
     write (u, "(A)")
 
     call local%modify_particle (6, stable = .true., polarized = .true.)
     call local%modify_particle (-6, stable = .true.)
     call local%model%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Global model"
     write (u, "(A)")
 
     call global%model%write (u)
     write (u, *)
     write (u, "(A,L1)")  "s is stable    = ", is_stable (25, global)
     write (u, "(A,L1)")  "f is polarized = ", is_polarized (6, global)
 
     write (u, "(A)")
     write (u, "(A)")  "* Local model"
     write (u, "(A)")
 
     call local%model%write (u)
     write (u, *)
     write (u, "(A,L1)")  "s is stable    = ", is_stable (25, local)
     write (u, "(A,L1)")  "f is polarized = ", is_polarized (6, local)
 
     write (u, *)
 
     write (u, "(A)", advance="no")  "Global model variable: "
     model_vars => global%model%get_var_list_ptr ()
     call model_vars%write_var (var_name, u)
 
     write (u, "(A)", advance="no")  "Local model variable: "
     associate (model_var_list_ptr => local%model%get_var_list_ptr())
        call model_var_list_ptr%write_var (var_name, u)
     end associate
 
     write (u, "(A)")
     write (u, "(A)")  "* Restore global"
 
     call local%deactivate (global, keep_local = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Global model"
     write (u, "(A)")
 
     call global%model%write (u)
     write (u, *)
     write (u, "(A,L1)")  "s is stable    = ", is_stable (25, global)
     write (u, "(A,L1)")  "f is polarized = ", is_polarized (6, global)
 
     write (u, "(A)")
     write (u, "(A)")  "* Local model"
     write (u, "(A)")
 
     call local%model%write (u)
     write (u, *)
     write (u, "(A,L1)")  "s is stable    = ", is_stable (25, local)
     write (u, "(A,L1)")  "f is polarized = ", is_polarized (6, local)
 
     write (u, *)
 
     write (u, "(A)", advance="no")  "Global model variable: "
     model_vars => global%model%get_var_list_ptr ()
     call model_vars%write_var (var_name, u)
 
     write (u, "(A)", advance="no")  "Local model variable: "
     associate (model_var_list_ptr => local%model%get_var_list_ptr())
        call model_var_list_ptr%write_var (var_name, u)
     end associate
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call local%model%final ()
     deallocate (local%model)
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_6"
 
   end subroutine rt_data_6
 
 @ %def rt_data_6
 @
 \subsubsection{Result variables}
 Initialize result variables and check that they are accessible via the
 global variable list.
 <<RT data: execute tests>>=
   call test (rt_data_7, "rt_data_7", &
        "result variables", &
        u, results)
 <<RT data: test declarations>>=
   public :: rt_data_7
 <<RT data: tests>>=
   subroutine rt_data_7 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: rt_data_7"
     write (u, "(A)")  "*   Purpose: set and access result variables"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process variables"
     write (u, "(A)")
 
     call global%global_init ()
     call global%process_stack%init_result_vars (var_str ("testproc"))
 
     call global%var_list%write_var (&
          var_str ("integral(testproc)"), u, defined=.true.)
     call global%var_list%write_var (&
          var_str ("error(testproc)"), u, defined=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_7"
 
   end subroutine rt_data_7
 
 @ %def rt_data_7
 @
 \subsubsection{Beam energy}
 If beam parameters are set, the variable [[sqrts]] is not necessarily
 the collision energy.  The method [[get_sqrts]] fetches the correct value.
 <<RT data: execute tests>>=
   call test (rt_data_8, "rt_data_8", &
        "beam energy", &
        u, results)
 <<RT data: test declarations>>=
   public :: rt_data_8
 <<RT data: tests>>=
   subroutine rt_data_8 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: rt_data_8"
     write (u, "(A)")  "*   Purpose: get correct collision energy"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize"
     write (u, "(A)")
 
     call global%global_init ()
 
     write (u, "(A)")  "* Set sqrts"
     write (u, "(A)")
 
     call global%set_real (var_str ("sqrts"), &
          1000._default, is_known = .true.)
     write (u, "(1x,A," // FMT_19 // ")")  "sqrts =", global%get_sqrts ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_8"
 
   end subroutine rt_data_8
 
 @ %def rt_data_8
 @
 \subsubsection{Local variable modifications}
 <<RT data: execute tests>>=
   call test (rt_data_9, "rt_data_9", &
        "local variables", &
        u, results)
 <<RT data: test declarations>>=
   public :: rt_data_9
 <<RT data: tests>>=
   subroutine rt_data_9 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global, local
     type(var_list_t), pointer :: var_list
 
     write (u, "(A)")  "* Test output: rt_data_9"
     write (u, "(A)")  "*   Purpose: handle local variables"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     write (u, "(A)")  "* Initialize global record and set some variables"
     write (u, "(A)")
 
     call global%global_init ()
     call global%select_model (var_str ("Test"))
 
     call global%set_real (var_str ("sqrts"), 17._default, is_known = .true.)
     call global%set_real (var_str ("luminosity"), 2._default, is_known = .true.)
     call global%model_set_real (var_str ("ff"), 0.5_default)
     call global%model_set_real (var_str ("gy"), 1.2_default)
 
     var_list => global%get_var_list_ptr ()
 
     call var_list%write_var (var_str ("sqrts"), u, defined=.true.)
     call var_list%write_var (var_str ("luminosity"), u, defined=.true.)
     call var_list%write_var (var_str ("ff"), u, defined=.true.)
     call var_list%write_var (var_str ("gy"), u, defined=.true.)
     call var_list%write_var (var_str ("mf"), u, defined=.true.)
     call var_list%write_var (var_str ("x"), u, defined=.true.)
 
     write (u, "(A)")
 
     write (u, "(1x,A,1x,F5.2)")  "sqrts      = ", &
          global%get_rval (var_str ("sqrts"))
     write (u, "(1x,A,1x,F5.2)")  "luminosity = ", &
          global%get_rval (var_str ("luminosity"))
     write (u, "(1x,A,1x,F5.2)")  "ff         = ", &
          global%get_rval (var_str ("ff"))
     write (u, "(1x,A,1x,F5.2)")  "gy         = ", &
          global%get_rval (var_str ("gy"))
     write (u, "(1x,A,1x,F5.2)")  "mf         = ", &
          global%get_rval (var_str ("mf"))
     write (u, "(1x,A,1x,F5.2)")  "x          = ", &
          global%get_rval (var_str ("x"))
 
     write (u, "(A)")
     write (u, "(A)")  "* Create local record with local variables"
     write (u, "(A)")
 
     call local%local_init (global)
 
     call local%append_real (var_str ("luminosity"), intrinsic = .true.)
     call local%append_real (var_str ("x"), user = .true.)
 
     call local%activate ()
 
     var_list => local%get_var_list_ptr ()
 
     call var_list%write_var (var_str ("sqrts"), u)
     call var_list%write_var (var_str ("luminosity"), u)
     call var_list%write_var (var_str ("ff"), u)
     call var_list%write_var (var_str ("gy"), u)
     call var_list%write_var (var_str ("mf"), u)
     call var_list%write_var (var_str ("x"), u, defined=.true.)
 
     write (u, "(A)")
 
     write (u, "(1x,A,1x,F5.2)")  "sqrts      = ", &
          local%get_rval (var_str ("sqrts"))
     write (u, "(1x,A,1x,F5.2)")  "luminosity = ", &
          local%get_rval (var_str ("luminosity"))
     write (u, "(1x,A,1x,F5.2)")  "ff         = ", &
          local%get_rval (var_str ("ff"))
     write (u, "(1x,A,1x,F5.2)")  "gy         = ", &
          local%get_rval (var_str ("gy"))
     write (u, "(1x,A,1x,F5.2)")  "mf         = ", &
          local%get_rval (var_str ("mf"))
     write (u, "(1x,A,1x,F5.2)")  "x          = ", &
          local%get_rval (var_str ("x"))
 
     write (u, "(A)")
     write (u, "(A)")  "* Modify some local variables"
     write (u, "(A)")
 
     call local%set_real (var_str ("luminosity"), 42._default, is_known=.true.)
     call local%set_real (var_str ("x"), 6.66_default, is_known=.true.)
     call local%model_set_real (var_str ("ff"), 0.7_default)
 
     var_list => local%get_var_list_ptr ()
 
     call var_list%write_var (var_str ("sqrts"), u)
     call var_list%write_var (var_str ("luminosity"), u)
     call var_list%write_var (var_str ("ff"), u)
     call var_list%write_var (var_str ("gy"), u)
     call var_list%write_var (var_str ("mf"), u)
     call var_list%write_var (var_str ("x"), u, defined=.true.)
 
     write (u, "(A)")
 
     write (u, "(1x,A,1x,F5.2)")  "sqrts      = ", &
          local%get_rval (var_str ("sqrts"))
     write (u, "(1x,A,1x,F5.2)")  "luminosity = ", &
          local%get_rval (var_str ("luminosity"))
     write (u, "(1x,A,1x,F5.2)")  "ff         = ", &
          local%get_rval (var_str ("ff"))
     write (u, "(1x,A,1x,F5.2)")  "gy         = ", &
          local%get_rval (var_str ("gy"))
     write (u, "(1x,A,1x,F5.2)")  "mf         = ", &
          local%get_rval (var_str ("mf"))
     write (u, "(1x,A,1x,F5.2)")  "x          = ", &
          local%get_rval (var_str ("x"))
 
     write (u, "(A)")
     write (u, "(A)")  "* Restore globals"
     write (u, "(A)")
 
     call local%deactivate (global)
 
     var_list => global%get_var_list_ptr ()
 
     call var_list%write_var (var_str ("sqrts"), u)
     call var_list%write_var (var_str ("luminosity"), u)
     call var_list%write_var (var_str ("ff"), u)
     call var_list%write_var (var_str ("gy"), u)
     call var_list%write_var (var_str ("mf"), u)
     call var_list%write_var (var_str ("x"), u, defined=.true.)
 
     write (u, "(A)")
 
     write (u, "(1x,A,1x,F5.2)")  "sqrts      = ", &
          global%get_rval (var_str ("sqrts"))
     write (u, "(1x,A,1x,F5.2)")  "luminosity = ", &
          global%get_rval (var_str ("luminosity"))
     write (u, "(1x,A,1x,F5.2)")  "ff         = ", &
          global%get_rval (var_str ("ff"))
     write (u, "(1x,A,1x,F5.2)")  "gy         = ", &
          global%get_rval (var_str ("gy"))
     write (u, "(1x,A,1x,F5.2)")  "mf         = ", &
          global%get_rval (var_str ("mf"))
     write (u, "(1x,A,1x,F5.2)")  "x          = ", &
          global%get_rval (var_str ("x"))
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call local%local_final ()
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_9"
 
   end subroutine rt_data_9
 
 @ %def rt_data_9
 @
 \subsubsection{Descriptions}
 <<RT data: execute tests>>=
   call test(rt_data_10, "rt_data_10", &
             "descriptions", u, results)
 <<RT data: test declarations>>=
   public :: rt_data_10
 <<RT data: tests>>=
   subroutine rt_data_10 (u)
     integer, intent(in) :: u
     type(rt_data_t) :: global
     ! type(var_list_t) :: var_list
     write (u, "(A)")  "* Test output: rt_data_10"
     write (u, "(A)")  "*   Purpose: display descriptions"
     write (u, "(A)")
 
     call global%var_list%append_real (var_str ("sqrts"), &
           intrinsic=.true., &
           description=var_str ('Real variable in order to set the center-of-mass ' // &
           'energy for the collisions.'))
     call global%var_list%append_real (var_str ("luminosity"), 0._default, &
           intrinsic=.true., &
           description=var_str ('This specifier \ttt{luminosity = {\em ' // &
           '<num>}} sets the integrated luminosity (in inverse femtobarns, ' // &
           'fb${}^{-1}$) for the event generation of the processes in the ' // &
           '\sindarin\ input files.'))
     call global%var_list%append_int (var_str ("seed"), 1234, &
           intrinsic=.true., &
           description=var_str ('Integer variable \ttt{seed = {\em <num>}} ' // &
           'that allows to set a specific random seed \ttt{num}.'))
     call global%var_list%append_string (var_str ("$method"), var_str ("omega"), &
          intrinsic=.true., &
          description=var_str ('This string variable specifies the method ' // &
          'for the matrix elements to be used in the evaluation.'))
     call global%var_list%append_log (var_str ("?read_color_factors"), .true., &
           intrinsic=.true., &
           description=var_str ('This flag decides whether to read QCD ' // &
           'color factors from the matrix element provided by each method, ' // &
           'or to try and calculate the color factors in \whizard\ internally.'))
 
     call global%var_list%sort ()
 
     call global%write_var_descriptions (u)
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_10"
   end subroutine rt_data_10
 
 @ %def rt_data_10
 @
 \subsubsection{Export objects}
 Export objects are variables or other data that should be copied or otherwise
 applied to corresponding objects in the outer scope.
 
 We test appending and retrieval for the export list.
 <<RT data: execute tests>>=
   call test(rt_data_11, "rt_data_11", &
             "export objects", u, results)
 <<RT data: test declarations>>=
   public :: rt_data_11
 <<RT data: tests>>=
   subroutine rt_data_11 (u)
     integer, intent(in) :: u
     type(rt_data_t) :: global
     type(string_t), dimension(:), allocatable :: exports
     integer :: i
 
     write (u, "(A)")  "* Test output: rt_data_11"
     write (u, "(A)")  "*   Purpose: handle export object list"
     write (u, "(A)")
 
     write (u, "(A)")  "* Empty export list"
     write (u, "(A)")
     
     call global%write_exports (u)
 
     write (u, "(A)")  "* Add an entry"
     write (u, "(A)")
     
     allocate (exports (1))
     exports(1) = var_str ("results")
     do i = 1, size (exports)
        write (u, "('+ ',A)")  char (exports(i))
     end do
     write (u, *)
     
     call global%append_exports (exports)
     call global%write_exports (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Add more entries, including doubler"
     write (u, "(A)")
     
     deallocate (exports)
     allocate (exports (3))
     exports(1) = var_str ("foo")
     exports(2) = var_str ("results")
     exports(3) = var_str ("bar")
     do i = 1, size (exports)
        write (u, "('+ ',A)")  char (exports(i))
     end do
     write (u, *)
 
     call global%append_exports (exports)
     call global%write_exports (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
     
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: rt_data_11"
   end subroutine rt_data_11
 
 @ %def rt_data_11
 @
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Select implementations}
 For abstract types (process core, integrator, phase space, etc.), we need a
 way to dynamically select a concrete type, using either data given by the user
 or a previous selection of a concrete type.  This is done by subroutines in
 the current module.
 
 We would like to put this in the [[me_methods]] folder but it also
 depends on [[gosam]] and [[openloops]], so it is unclear where to put
 it.
 <<[[dispatch_me_methods.f90]]>>=
 <<File header>>
 
 module dispatch_me_methods
 
 <<Use strings>>
 <<Use debug>>
   use physics_defs, only: BORN
   use diagnostics
   use sm_qcd
   use variables, only: var_list_t
   use models
   use model_data
 
   use prc_core_def
   use prc_core
   use prc_test_core
   use prc_template_me
   use prc_test
   use prc_omega
   use prc_external
   use prc_gosam
   use prc_openloops
   use prc_recola
   use prc_threshold
 
 <<Standard module head>>
 
 <<Dispatch me methods: public>>
 
 contains
 
 <<Dispatch me methods: procedures>>
 
 end module dispatch_me_methods
 @ %def dispatch_me_methods
 @
 \subsection{Process Core Definition}
 The [[prc_core_def_t]] abstract type can be instantiated by providing a
 [[$method]] string variable.
 
 Note: [[core_def]] has intent(inout) because gfortran 4.7.1 crashes for
 intent(out).
 <<Dispatch me methods: public>>=
   public :: dispatch_core_def
 <<Dispatch me methods: procedures>>=
   subroutine dispatch_core_def (core_def, prt_in, prt_out, &
        model, var_list, id, nlo_type, method)
     class(prc_core_def_t), allocatable, intent(inout) :: core_def
     type(string_t), dimension(:), intent(in) :: prt_in
     type(string_t), dimension(:), intent(in) :: prt_out
     type(model_t), pointer, intent(in) :: model
     type(var_list_t), intent(in) :: var_list
     type(string_t), intent(in), optional :: id
     integer, intent(in), optional :: nlo_type
     type(string_t), intent(in), optional :: method
     type(string_t) :: model_name, meth
     type(string_t) :: ufo_path
     type(string_t) :: restrictions
     logical :: ufo
     logical :: cms_scheme
     logical :: openmp_support
     logical :: report_progress
     logical :: diags, diags_color
     logical :: write_phs_output
     type(string_t) :: extra_options, correction_type
     integer :: nlo
     integer :: alpha_power
     integer :: alphas_power
     if (present (method)) then
        meth = method
     else
        meth = var_list%get_sval (var_str ("$method"))
     end if
     if (debug_on) call msg_debug2 (D_CORE, "dispatch_core_def")
     if (associated (model)) then
        model_name = model%get_name ()
        cms_scheme = model%get_scheme () == "Complex_Mass_Scheme"
        ufo = model%is_ufo_model ()
        ufo_path = model%get_ufo_path ()
     else
        model_name = ""
        cms_scheme = .false.
        ufo = .false.
     end if
     restrictions = var_list%get_sval (&
          var_str ("$restrictions"))
     diags = var_list%get_lval (&
          var_str ("?vis_diags"))
     diags_color = var_list%get_lval (&
          var_str ("?vis_diags_color"))
     openmp_support = var_list%get_lval (&
          var_str ("?omega_openmp"))
     report_progress = var_list%get_lval (&
          var_str ("?report_progress"))
     write_phs_output = var_list%get_lval (&
          var_str ("?omega_write_phs_output"))
     extra_options = var_list%get_sval (&
          var_str ("$omega_flags"))
     nlo = BORN;  if (present (nlo_type))  nlo = nlo_type
     alpha_power = var_list%get_ival (var_str ("alpha_power"))
     alphas_power = var_list%get_ival (var_str ("alphas_power"))
     correction_type = var_list%get_sval (var_str ("$nlo_correction_type"))
     if (debug_on) call msg_debug2 (D_CORE, "dispatching core method: ", meth)
     select case (char (meth))
     case ("unit_test")
        allocate (prc_test_def_t :: core_def)
        select type (core_def)
        type is (prc_test_def_t)
           call core_def%init (model_name, prt_in, prt_out)
        end select
     case ("template")
        allocate (template_me_def_t :: core_def)
        select type (core_def)
        type is (template_me_def_t)
           call core_def%init (model, prt_in, prt_out, unity = .false.)
        end select
     case ("template_unity")
        allocate (template_me_def_t :: core_def)
        select type (core_def)
        type is (template_me_def_t)
           call core_def%init (model, prt_in, prt_out, unity = .true.)
        end select
     case ("omega")
        allocate (omega_def_t :: core_def)
        select type (core_def)
        type is (omega_def_t)
           call core_def%init (model_name, prt_in, prt_out, &
                .false., ufo, ufo_path, &
                restrictions, cms_scheme, &
                openmp_support, report_progress, write_phs_output, &
                extra_options, diags, diags_color)
        end select
     case ("ovm")
        allocate (omega_def_t :: core_def)
        select type (core_def)
        type is (omega_def_t)
           call core_def%init (model_name, prt_in, prt_out, &
                .true., .false., var_str (""), &
                restrictions, cms_scheme, &
                openmp_support, report_progress, write_phs_output, &
                extra_options, diags, diags_color)
        end select
     case ("gosam")
       allocate (gosam_def_t :: core_def)
       select type (core_def)
       type is (gosam_def_t)
         if (present (id)) then
            call core_def%init (id, model_name, prt_in, &
                 prt_out, nlo, restrictions, var_list)
         else
            call msg_fatal ("Dispatch GoSam def: No id!")
         end if
       end select
     case ("openloops")
        allocate (openloops_def_t :: core_def)
        select type (core_def)
        type is (openloops_def_t)
           if (present (id)) then
              call core_def%init (id, model_name, prt_in, &
                   prt_out, nlo, restrictions, var_list)
           else
              call msg_fatal ("Dispatch OpenLoops def: No id!")
           end if
        end select
     case ("recola")
        call abort_if_recola_not_active ()
        allocate (recola_def_t :: core_def)
        select type (core_def)
        type is (recola_def_t)
           if (present (id)) then
              call core_def%init (id, model_name, prt_in, prt_out, &
                   nlo, alpha_power, alphas_power, correction_type, &
                   restrictions)
           else
              call msg_fatal ("Dispatch RECOLA def: No id!")
           end if
        end select
     case ("dummy")
        allocate (prc_external_test_def_t :: core_def)
        select type (core_def)
        type is (prc_external_test_def_t)
           if (present (id)) then
              call core_def%init (id, model_name, prt_in, prt_out)
           else
              call msg_fatal ("Dispatch User-Defined Test def: No id!")
           end if
        end select
     case ("threshold")
        allocate (threshold_def_t :: core_def)
        select type (core_def)
        type is (threshold_def_t)
           if (present (id)) then
              call core_def%init (id, model_name, prt_in, prt_out, &
                   nlo, restrictions)
           else
              call msg_fatal ("Dispatch Threshold def: No id!")
           end if
        end select
     case default
        call msg_fatal ("Process configuration: method '" &
             // char (meth) // "' not implemented")
     end select
   end subroutine dispatch_core_def
 
 @ %def dispatch_core_def
 @
 \subsection{Process core allocation}
 Here we allocate an object of abstract type [[prc_core_t]] with a concrete
 type that matches a process definition.  The [[prc_omega_t]] extension
 will require the current parameter set, so we take the opportunity to
 grab it from the model.
 <<Dispatch me methods: public>>=
   public :: dispatch_core
 <<Dispatch me methods: procedures>>=
   subroutine dispatch_core (core, core_def, model, &
        helicity_selection, qcd, use_color_factors, has_beam_pol)
     class(prc_core_t), allocatable, intent(inout) :: core
     class(prc_core_def_t), intent(in) :: core_def
     class(model_data_t), intent(in), target, optional :: model
     type(helicity_selection_t), intent(in), optional :: helicity_selection
     type(qcd_t), intent(in), optional :: qcd
     logical, intent(in), optional :: use_color_factors
     logical, intent(in), optional :: has_beam_pol
     select type (core_def)
     type is (prc_test_def_t)
        allocate (test_t :: core)
     type is (template_me_def_t)
        allocate (prc_template_me_t :: core)
        select type (core)
        type is (prc_template_me_t)
           call core%set_parameters (model)
        end select
     class is (omega_def_t)
        if (.not. allocated (core)) allocate (prc_omega_t :: core)
        select type (core)
        type is (prc_omega_t)
           call core%set_parameters (model, &
                helicity_selection, qcd, use_color_factors)
        end select
     type is (gosam_def_t)
       if (.not. allocated (core)) allocate (prc_gosam_t :: core)
       select type (core)
       type is (prc_gosam_t)
         call core%set_parameters (qcd)
       end select
     type is (openloops_def_t)
       if (.not. allocated (core)) allocate (prc_openloops_t :: core)
       select type (core)
       type is (prc_openloops_t)
          call core%set_parameters (qcd)
       end select
     type is (recola_def_t)
       if (.not. allocated (core)) allocate (prc_recola_t :: core)
       select type (core)
       type is (prc_recola_t)
          call core%set_parameters (qcd, model)
       end select
     type is (prc_external_test_def_t)
       if (.not. allocated (core)) allocate (prc_external_test_t :: core)
       select type (core)
       type is (prc_external_test_t)
          call core%set_parameters (qcd, model)
       end select
     type is (threshold_def_t)
       if (.not. allocated (core)) allocate (prc_threshold_t :: core)
       select type (core)
       type is (prc_threshold_t)
          call core%set_parameters (qcd, model)
          call core%set_beam_pol (has_beam_pol)
       end select
     class default
        call msg_bug ("Process core: unexpected process definition type")
     end select
   end subroutine dispatch_core
 
 @ %def dispatch_core
 @
 \subsection{Process core update and restoration}
 Here we take an existing object of abstract type [[prc_core_t]] and
 update the parameters as given by the current state of [[model]].
 Optionally, we can save the previous state as [[saved_core]].  The
 second routine restores the original from the save.
 
 (In the test case, there is no possible update.)
 <<Dispatch me methods: public>>=
   public :: dispatch_core_update
   public :: dispatch_core_restore
 <<Dispatch me methods: procedures>>=
   subroutine dispatch_core_update &
        (core, model, helicity_selection, qcd, saved_core)
 
     class(prc_core_t), allocatable, intent(inout) :: core
     class(model_data_t), intent(in), optional, target :: model
     type(helicity_selection_t), intent(in), optional :: helicity_selection
     type(qcd_t), intent(in), optional :: qcd
     class(prc_core_t), allocatable, intent(inout), optional :: saved_core
 
     if (present (saved_core)) then
        allocate (saved_core, source = core)
     end if
     select type (core)
     type is (test_t)
     type is (prc_omega_t)
        call core%set_parameters (model, helicity_selection, qcd)
        call core%activate_parameters ()
     class is (prc_external_t)
       call msg_message ("Updating user defined cores is not implemented yet.")
     class default
        call msg_bug ("Process core update: unexpected process definition type")
     end select
   end subroutine dispatch_core_update
 
   subroutine dispatch_core_restore (core, saved_core)
 
     class(prc_core_t), allocatable, intent(inout) :: core
     class(prc_core_t), allocatable, intent(inout) :: saved_core
 
     call move_alloc (from = saved_core, to = core)
     select type (core)
     type is (test_t)
     type is (prc_omega_t)
        call core%activate_parameters ()
     class default
        call msg_bug ("Process core restore: unexpected process definition type")
     end select
   end subroutine dispatch_core_restore
 
 @ %def dispatch_core_update dispatch_core_restore
 @
 \subsection{Unit Tests}
 Test module, followed by the corresponding implementation module.
 <<[[dispatch_ut.f90]]>>=
 <<File header>>
 
 module dispatch_ut
   use unit_tests
   use dispatch_uti
 
 <<Standard module head>>
 
 <<Dispatch: public test>>
 
 <<Dispatch: public test auxiliary>>
 
 contains
 
 <<Dispatch: test driver>>
 
 end module dispatch_ut
 @ %def dispatch_ut
 @
 <<[[dispatch_uti.f90]]>>=
 <<File header>>
 
 module dispatch_uti
 <<Use kinds>>
 <<Use strings>>
   use os_interface, only: os_data_t
   use physics_defs, only: ELECTRON, PROTON
   use sm_qcd, only: qcd_t
   use flavors, only: flavor_t
   use interactions, only: reset_interaction_counter
   use pdg_arrays, only: pdg_array_t, assignment(=)
   use prc_core_def, only: prc_core_def_t
   use prc_test_core, only: test_t
   use prc_core, only: prc_core_t
   use prc_test, only: prc_test_def_t
   use prc_omega, only: omega_def_t, prc_omega_t
   use sf_mappings, only: sf_channel_t
   use sf_base, only: sf_data_t, sf_config_t
   use phs_base, only: phs_channel_collection_t
   use variables, only: var_list_t
   use model_data, only: model_data_t
   use models, only: syntax_model_file_init, syntax_model_file_final
   use rt_data, only: rt_data_t
 
   use dispatch_phase_space, only: dispatch_sf_channels
   use dispatch_beams, only: sf_prop_t, dispatch_qcd
   use dispatch_beams, only: dispatch_sf_config, dispatch_sf_data
   use dispatch_me_methods, only: dispatch_core_def, dispatch_core
   use dispatch_me_methods, only: dispatch_core_update, dispatch_core_restore
 
   use sf_base_ut, only: sf_test_data_t
 
 <<Standard module head>>
 
 <<Dispatch: public test auxiliary>>
 
 <<Dispatch: test declarations>>
 
 contains
 
 <<Dispatch: tests>>
 
 <<Dispatch: test auxiliary>>
 
 end module dispatch_uti
 
 @ %def dispatch_uti
 @ API: driver for the unit tests below.
 <<Dispatch: public test>>=
   public :: dispatch_test
 <<Dispatch: test driver>>=
   subroutine dispatch_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Dispatch: execute tests>>
   end subroutine dispatch_test
 
 @ %def dispatch_test
 @
 \subsubsection{Select type: process definition}
 <<Dispatch: execute tests>>=
   call test (dispatch_1, "dispatch_1", &
        "process configuration method", &
        u, results)
 <<Dispatch: test declarations>>=
   public :: dispatch_1
 <<Dispatch: tests>>=
   subroutine dispatch_1 (u)
     integer, intent(in) :: u
     type(string_t), dimension(2) :: prt_in, prt_out
     type(rt_data_t), target :: global
     class(prc_core_def_t), allocatable :: core_def
 
     write (u, "(A)")  "* Test output: dispatch_1"
     write (u, "(A)")  "*   Purpose: select process configuration method"
     write (u, "(A)")
 
     call global%global_init ()
 
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
 
     prt_in = [var_str ("a"), var_str ("b")]
     prt_out = [var_str ("c"), var_str ("d")]
 
     write (u, "(A)")  "* Allocate core_def as prc_test_def"
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call dispatch_core_def (core_def, prt_in, prt_out, global%model, global%var_list)
     select type (core_def)
     type is (prc_test_def_t)
        call core_def%write (u)
     end select
 
     deallocate (core_def)
 
     write (u, "(A)")
     write (u, "(A)")  "* Allocate core_def as omega_def"
     write (u, "(A)")
 
     call global%set_string (var_str ("$method"), &
          var_str ("omega"), is_known = .true.)
     call dispatch_core_def (core_def, prt_in, prt_out, global%model, global%var_list)
     select type (core_def)
     type is (omega_def_t)
        call core_def%write (u)
     end select
 
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: dispatch_1"
 
   end subroutine dispatch_1
 
 @ %def dispatch_1
 @
 \subsubsection{Select type: process core}
 <<Dispatch: execute tests>>=
   call test (dispatch_2, "dispatch_2", &
        "process core", &
        u, results)
 <<Dispatch: test declarations>>=
   public :: dispatch_2
 <<Dispatch: tests>>=
   subroutine dispatch_2 (u)
     integer, intent(in) :: u
     type(string_t), dimension(2) :: prt_in, prt_out
     type(rt_data_t), target :: global
     class(prc_core_def_t), allocatable :: core_def
     class(prc_core_t), allocatable :: core
 
     write (u, "(A)")  "* Test output: dispatch_2"
     write (u, "(A)")  "*   Purpose: select process configuration method"
     write (u, "(A)")  "             and allocate process core"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call global%global_init ()
 
     prt_in = [var_str ("a"), var_str ("b")]
     prt_out = [var_str ("c"), var_str ("d")]
 
     write (u, "(A)")  "* Allocate core as test_t"
     write (u, "(A)")
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call dispatch_core_def (core_def, prt_in, prt_out, global%model, global%var_list)
     call dispatch_core (core, core_def)
     select type (core)
     type is (test_t)
        call core%write (u)
     end select
 
     deallocate (core)
     deallocate (core_def)
 
     write (u, "(A)")
     write (u, "(A)")  "* Allocate core as prc_omega_t"
     write (u, "(A)")
 
     call global%set_string (var_str ("$method"), &
          var_str ("omega"), is_known = .true.)
     call dispatch_core_def (core_def, prt_in, prt_out, global%model, global%var_list)
 
     call global%select_model (var_str ("Test"))
 
     call global%set_log (&
          var_str ("?helicity_selection_active"), &
          .true., is_known = .true.)
     call global%set_real (&
          var_str ("helicity_selection_threshold"), &
          1e9_default, is_known = .true.)
     call global%set_int (&
          var_str ("helicity_selection_cutoff"), &
          10, is_known = .true.)
 
     call dispatch_core (core, core_def, &
          global%model, &
          global%get_helicity_selection ())
     call core_def%allocate_driver (core%driver, var_str (""))
 
     select type (core)
     type is (prc_omega_t)
        call core%write (u)
     end select
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: dispatch_2"
 
   end subroutine dispatch_2
 
 @ %def dispatch_2
 @
 \subsubsection{Select type: structure-function data}
 This is an extra dispatcher that enables the test structure
 functions.  This procedure should be assigned to the
 [[dispatch_sf_data_extra]] hook before any tests are executed.
 <<Dispatch: public test auxiliary>>=
   public :: dispatch_sf_data_test
 <<Dispatch: test auxiliary>>=
   subroutine dispatch_sf_data_test (data, sf_method, i_beam, sf_prop, &
        var_list, var_list_global, model, os_data, sqrts, pdg_in, pdg_prc, polarized)
     class(sf_data_t), allocatable, intent(inout) :: data
     type(string_t), intent(in) :: sf_method
     integer, dimension(:), intent(in) :: i_beam
     type(var_list_t), intent(in) :: var_list
     type(var_list_t), intent(inout) :: var_list_global
     class(model_data_t), target, intent(in) :: model
     type(os_data_t), intent(in) :: os_data
     real(default), intent(in) :: sqrts
     type(pdg_array_t), dimension(:), intent(inout) :: pdg_in
     type(pdg_array_t), dimension(:,:), intent(in) :: pdg_prc
     type(sf_prop_t), intent(inout) :: sf_prop
     logical, intent(in) :: polarized
     select case (char (sf_method))
     case ("sf_test_0", "sf_test_1")
        allocate (sf_test_data_t :: data)
        select type (data)
        type is (sf_test_data_t)
           select case (char (sf_method))
           case ("sf_test_0");  call data%init (model, pdg_in(i_beam(1)))
           case ("sf_test_1");  call data%init (model, pdg_in(i_beam(1)),&
                mode = 1)
           end select
        end select
     end select
   end subroutine dispatch_sf_data_test
 
 @ %def dispatch_sf_data_test
 @ The actual test. We can't move this to [[beams]] as it depends on
 [[model_features]] for the [[model_list_t]].
 <<Dispatch: execute tests>>=
   call test (dispatch_7, "dispatch_7", &
        "structure-function data", &
        u, results)
 <<Dispatch: test declarations>>=
   public :: dispatch_7
 <<Dispatch: tests>>=
   subroutine dispatch_7 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     type(os_data_t) :: os_data
     type(string_t) :: prt, sf_method
     type(sf_prop_t) :: sf_prop
     class(sf_data_t), allocatable :: data
     type(pdg_array_t), dimension(1) :: pdg_in
     type(pdg_array_t), dimension(1,1) :: pdg_prc
     type(pdg_array_t), dimension(1) :: pdg_out
     integer, dimension(:), allocatable :: pdg1
 
     write (u, "(A)")  "* Test output: dispatch_7"
     write (u, "(A)")  "*   Purpose: select and configure &
          &structure function data"
     write (u, "(A)")
 
     call global%global_init ()
 
     call os_data%init ()
     call syntax_model_file_init ()
     call global%select_model (var_str ("QCD"))
 
     call reset_interaction_counter ()
     call global%set_real (var_str ("sqrts"), &
          14000._default, is_known = .true.)
     prt = "p"
     call global%beam_structure%init_sf ([prt, prt], [1])
     pdg_in = 2212
 
     write (u, "(A)")  "* Allocate data as sf_pdf_builtin_t"
     write (u, "(A)")
 
     sf_method = "pdf_builtin"
     call dispatch_sf_data (data, sf_method, [1], sf_prop, &
          global%get_var_list_ptr (), global%var_list, &
          global%model, global%os_data, global%get_sqrts (), &
          pdg_in, pdg_prc, .false.)
     call data%write (u)
 
     call data%get_pdg_out (pdg_out)
     pdg1 = pdg_out(1)
     write (u, "(A)")
     write (u, "(1x,A,99(1x,I0))")  "PDG(out) = ", pdg1
 
     deallocate (data)
 
     write (u, "(A)")
     write (u, "(A)")  "* Allocate data for different PDF set"
     write (u, "(A)")
 
     pdg_in = 2212
 
     call global%set_string (var_str ("$pdf_builtin_set"), &
          var_str ("CTEQ6M"), is_known = .true.)
     sf_method = "pdf_builtin"
     call dispatch_sf_data (data, sf_method, [1], sf_prop, &
          global%get_var_list_ptr (), global%var_list, &
          global%model, global%os_data, global%get_sqrts (), &
          pdg_in, pdg_prc, .false.)
     call data%write (u)
 
     call data%get_pdg_out (pdg_out)
     pdg1 = pdg_out(1)
     write (u, "(A)")
     write (u, "(1x,A,99(1x,I0))")  "PDG(out) = ", pdg1
 
     deallocate (data)
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: dispatch_7"
 
   end subroutine dispatch_7
 
 @ %def dispatch_7
 @
 \subsubsection{Beam structure}
 The actual test. We can't move this to [[beams]] as it depends on
 [[model_features]] for the [[model_list_t]].
 <<Dispatch: execute tests>>=
   call test (dispatch_8, "dispatch_8", &
        "beam structure", &
        u, results)
 <<Dispatch: test declarations>>=
   public :: dispatch_8
 <<Dispatch: tests>>=
   subroutine dispatch_8 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     type(os_data_t) :: os_data
     type(flavor_t), dimension(2) :: flv
     type(sf_config_t), dimension(:), allocatable :: sf_config
     type(sf_prop_t) :: sf_prop
     type(sf_channel_t), dimension(:), allocatable :: sf_channel
     type(phs_channel_collection_t) :: coll
     type(string_t) :: sf_string
     integer :: i
     type(pdg_array_t), dimension (2,1) :: pdg_prc
 
     write (u, "(A)")  "* Test output: dispatch_8"
     write (u, "(A)")  "*   Purpose: configure a structure-function chain"
     write (u, "(A)")
 
     call global%global_init ()
 
     call os_data%init ()
     call syntax_model_file_init ()
     call global%select_model (var_str ("QCD"))
 
     write (u, "(A)")  "* Allocate LHC beams with PDF builtin"
     write (u, "(A)")
 
     call flv(1)%init (PROTON, global%model)
     call flv(2)%init (PROTON, global%model)
 
     call reset_interaction_counter ()
     call global%set_real (var_str ("sqrts"), &
          14000._default, is_known = .true.)
 
     call global%beam_structure%init_sf (flv%get_name (), [1])
     call global%beam_structure%set_sf (1, 1, var_str ("pdf_builtin"))
 
     call dispatch_sf_config (sf_config, sf_prop, global%beam_structure, &
          global%get_var_list_ptr (), global%var_list, &
          global%model, global%os_data, global%get_sqrts (), pdg_prc)
     do i = 1, size (sf_config)
        call sf_config(i)%write (u)
     end do
 
     call dispatch_sf_channels (sf_channel, sf_string, sf_prop, coll, &
          global%var_list, global%get_sqrts(), global%beam_structure)
     write (u, "(1x,A)")  "Mapping configuration:"
     do i = 1, size (sf_channel)
        write (u, "(2x)", advance = "no")
        call sf_channel(i)%write (u)
     end do
 
     write (u, "(A)")
     write (u, "(A)")  "* Allocate ILC beams with CIRCE1"
     write (u, "(A)")
 
     call global%select_model (var_str ("QED"))
     call flv(1)%init ( ELECTRON, global%model)
     call flv(2)%init (-ELECTRON, global%model)
 
     call reset_interaction_counter ()
     call global%set_real (var_str ("sqrts"), &
          500._default, is_known = .true.)
     call global%set_log (var_str ("?circe1_generate"), &
          .false., is_known = .true.)
 
     call global%beam_structure%init_sf (flv%get_name (), [1])
     call global%beam_structure%set_sf (1, 1, var_str ("circe1"))
 
     call dispatch_sf_config (sf_config, sf_prop, global%beam_structure, &
          global%get_var_list_ptr (), global%var_list, &
          global%model, global%os_data, global%get_sqrts (), pdg_prc)
     do i = 1, size (sf_config)
        call sf_config(i)%write (u)
     end do
 
     call dispatch_sf_channels (sf_channel, sf_string, sf_prop, coll, &
          global%var_list, global%get_sqrts(), global%beam_structure)
     write (u, "(1x,A)")  "Mapping configuration:"
     do i = 1, size (sf_channel)
        write (u, "(2x)", advance = "no")
        call sf_channel(i)%write (u)
     end do
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: dispatch_8"
 
   end subroutine dispatch_8
 
 @ %def dispatch_8
 @
 \subsubsection{Update process core parameters}
 This test dispatches a process core, temporarily modifies parameters,
 then restores the original.
 <<Dispatch: execute tests>>=
   call test (dispatch_10, "dispatch_10", &
        "process core update", &
        u, results)
 <<Dispatch: test declarations>>=
   public :: dispatch_10
 <<Dispatch: tests>>=
   subroutine dispatch_10 (u)
     integer, intent(in) :: u
     type(string_t), dimension(2) :: prt_in, prt_out
     type(rt_data_t), target :: global
     class(prc_core_def_t), allocatable :: core_def
     class(prc_core_t), allocatable :: core, saved_core
     type(var_list_t), pointer :: model_vars
 
     write (u, "(A)")  "* Test output: dispatch_10"
     write (u, "(A)")  "*   Purpose: select process configuration method,"
     write (u, "(A)")  "             allocate process core,"
     write (u, "(A)")  "             temporarily reset parameters"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call global%global_init ()
 
     prt_in = [var_str ("a"), var_str ("b")]
     prt_out = [var_str ("c"), var_str ("d")]
 
     write (u, "(A)")  "* Allocate core as prc_omega_t"
     write (u, "(A)")
 
     call global%set_string (var_str ("$method"), &
          var_str ("omega"), is_known = .true.)
     call dispatch_core_def (core_def, prt_in, prt_out, global%model, global%var_list)
 
     call global%select_model (var_str ("Test"))
 
     call dispatch_core (core, core_def, global%model)
     call core_def%allocate_driver (core%driver, var_str (""))
 
     select type (core)
     type is (prc_omega_t)
        call core%write (u)
     end select
 
     write (u, "(A)")
     write (u, "(A)")  "* Update core with modified model and helicity selection"
     write (u, "(A)")
 
     model_vars => global%model%get_var_list_ptr ()
 
     call model_vars%set_real (var_str ("gy"), 2._default, &
          is_known = .true.)
     call global%model%update_parameters ()
 
     call global%set_log (&
          var_str ("?helicity_selection_active"), &
          .true., is_known = .true.)
     call global%set_real (&
          var_str ("helicity_selection_threshold"), &
          2e10_default, is_known = .true.)
     call global%set_int (&
          var_str ("helicity_selection_cutoff"), &
          5, is_known = .true.)
 
     call dispatch_core_update (core, &
          global%model, &
          global%get_helicity_selection (), &
          saved_core = saved_core)
     select type (core)
     type is (prc_omega_t)
        call core%write (u)
     end select
 
     write (u, "(A)")
     write (u, "(A)")  "* Restore core from save"
     write (u, "(A)")
 
     call dispatch_core_restore (core, saved_core)
     select type (core)
     type is (prc_omega_t)
        call core%write (u)
     end select
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: dispatch_10"
 
   end subroutine dispatch_10
 
 @ %def dispatch_10
 @
 \subsubsection{QCD Coupling}
 This test dispatches an [[qcd]] object, which is used to compute the
 (running) coupling by one of several possible methods.
 
 We can't move this to [[beams]] as it depends on
 [[model_features]] for the [[model_list_t]].
 <<Dispatch: execute tests>>=
   call test (dispatch_11, "dispatch_11", &
        "QCD coupling", &
        u, results)
 <<Dispatch: test declarations>>=
   public :: dispatch_11
 <<Dispatch: tests>>=
   subroutine dispatch_11 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     type(var_list_t), pointer :: model_vars
     type(qcd_t) :: qcd
 
     write (u, "(A)")  "* Test output: dispatch_11"
     write (u, "(A)")  "*   Purpose: select QCD coupling formula"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call global%global_init ()
     call global%select_model (var_str ("SM"))
     model_vars => global%get_var_list_ptr ()
 
     write (u, "(A)")  "* Allocate alpha_s as fixed"
     write (u, "(A)")
 
     call global%set_log (var_str ("?alphas_is_fixed"), &
          .true., is_known = .true.)
     call dispatch_qcd (qcd, global%get_var_list_ptr (), global%os_data)
     call qcd%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Allocate alpha_s as running (built-in)"
     write (u, "(A)")
 
     call global%set_log (var_str ("?alphas_is_fixed"), &
          .false., is_known = .true.)
     call global%set_log (var_str ("?alphas_from_mz"), &
          .true., is_known = .true.)
     call global%set_int &
          (var_str ("alphas_order"), 1, is_known = .true.)
     call model_vars%set_real (var_str ("alphas"), 0.1234_default, &
           is_known=.true.)
     call model_vars%set_real (var_str ("mZ"), 91.234_default, &
           is_known=.true.)
     call dispatch_qcd (qcd, global%get_var_list_ptr (), global%os_data)
     call qcd%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Allocate alpha_s as running (built-in, Lambda defined)"
     write (u, "(A)")
 
     call global%set_log (var_str ("?alphas_from_mz"), &
          .false., is_known = .true.)
     call global%set_log (&
          var_str ("?alphas_from_lambda_qcd"), &
          .true., is_known = .true.)
     call global%set_real &
          (var_str ("lambda_qcd"), 250.e-3_default, &
           is_known=.true.)
     call global%set_int &
          (var_str ("alphas_order"), 2, is_known = .true.)
     call global%set_int &
          (var_str ("alphas_nf"), 4, is_known = .true.)
     call dispatch_qcd (qcd, global%get_var_list_ptr (), global%os_data)
     call qcd%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Allocate alpha_s as running (using builtin PDF set)"
     write (u, "(A)")
 
     call global%set_log (&
          var_str ("?alphas_from_lambda_qcd"), &
          .false., is_known = .true.)
     call global%set_log &
          (var_str ("?alphas_from_pdf_builtin"), &
          .true., is_known = .true.)
     call dispatch_qcd (qcd, global%get_var_list_ptr (), global%os_data)
     call qcd%write (u)
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: dispatch_11"
 
   end subroutine dispatch_11
 
 @ %def dispatch_11
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Process Configuration}
 This module communicates between the toplevel command structure with
 its runtime data set and the process-library handling modules which
 collect the definition of individual processes.  Its primary purpose
 is to select from the available matrix-element generating methods and
 configure the entry in the process library accordingly.
 <<[[process_configurations.f90]]>>=
 <<File header>>
 
 module process_configurations
 
 <<Use strings>>
 <<Use debug>>
   use diagnostics
   use io_units
   use physics_defs, only: BORN, NLO_VIRTUAL, NLO_REAL, NLO_DGLAP, &
        NLO_SUBTRACTION, NLO_MISMATCH
   use models
   use prc_core_def
   use particle_specifiers
   use process_libraries
   use rt_data
   use variables, only: var_list_t
 
   use dispatch_me_methods, only: dispatch_core_def
   use prc_external, only: prc_external_def_t
 
 <<Standard module head>>
 
 <<Process configurations: public>>
 
 <<Process configurations: types>>
 
 contains
 
 <<Process configurations: procedures>>
 
 end module process_configurations
 @ %def process_configurations
 @
 \subsection{Data Type}
 <<Process configurations: public>>=
   public :: process_configuration_t
 <<Process configurations: types>>=
   type :: process_configuration_t
      type(process_def_entry_t), pointer :: entry => null ()
      type(string_t) :: id
      integer :: num_id = 0
    contains
    <<Process configurations: process configuration: TBP>>
   end type process_configuration_t
 
 @ %def process_configuration_t
 @ Output (for unit tests).
 <<Process configurations: process configuration: TBP>>=
   procedure :: write => process_configuration_write
 <<Process configurations: procedures>>=
   subroutine process_configuration_write (config, unit)
     class(process_configuration_t), intent(in) :: config
     integer, intent(in), optional :: unit
     integer :: u
     u = given_output_unit (unit)
     write (u, "(A)")  "Process configuration:"
     if (associated (config%entry)) then
        call config%entry%write (u)
     else
        write (u, "(1x,3A)")  "ID    = '", char (config%id), "'"
        write (u, "(1x,A,1x,I0)")  "num ID =", config%num_id
        write (u, "(2x,A)")  "[no entry]"
     end if
   end subroutine process_configuration_write
 
 @ %def process_configuration_write
 @ Initialize a process.  We only need the name, the number of incoming
 particles, and the number of components.
 <<Process configurations: process configuration: TBP>>=
   procedure :: init => process_configuration_init
 <<Process configurations: procedures>>=
   subroutine process_configuration_init &
        (config, prc_name, n_in, n_components, model, var_list, nlo_process)
     class(process_configuration_t), intent(out) :: config
     type(string_t), intent(in) :: prc_name
     integer, intent(in) :: n_in
     integer, intent(in) :: n_components
     type(model_t), intent(in), pointer :: model
     type(var_list_t), intent(in) :: var_list
     logical, intent(in), optional :: nlo_process
     logical :: nlo_proc
     logical :: requires_resonances
     if (debug_on) call msg_debug (D_CORE, "process_configuration_init")
     config%id = prc_name
     if (present (nlo_process)) then
        nlo_proc = nlo_process
     else
        nlo_proc = .false.
     end if
     requires_resonances = var_list%get_lval (var_str ("?resonance_history"))
 
     if (debug_on) call msg_debug (D_CORE, "nlo_process", nlo_proc)
     allocate (config%entry)
     if (var_list%is_known (var_str ("process_num_id"))) then
        config%num_id = &
             var_list%get_ival (var_str ("process_num_id"))
        call config%entry%init (prc_name, &
             model = model, n_in = n_in, n_components = n_components, &
             num_id = config%num_id, &
             nlo_process = nlo_proc, &
             requires_resonances = requires_resonances)
     else
        call config%entry%init (prc_name, &
             model = model, n_in = n_in, n_components = n_components, &
             nlo_process = nlo_proc, &
             requires_resonances = requires_resonances)
     end if
   end subroutine process_configuration_init
 
 @ %def process_configuration_init
 @ Initialize a process component.  The details depend on the process method,
 which determines the type of the process component core.  We set the incoming
 and outgoing particles (as strings, to be interpreted by the process driver).
 All other information is taken from the variable list.
 
 The dispatcher gets only the names of the particles.  The process
 component definition gets the complete specifiers which contains a
 polarization flag and names of decay processes, where applicable.
 <<Process configurations: process configuration: TBP>>=
   procedure :: setup_component => process_configuration_setup_component
 <<Process configurations: procedures>>=
   subroutine process_configuration_setup_component &
        (config, i_component, prt_in, prt_out, model, var_list, &
         nlo_type, can_be_integrated)
     class(process_configuration_t), intent(inout) :: config
     integer, intent(in) :: i_component
     type(prt_spec_t), dimension(:), intent(in) :: prt_in
     type(prt_spec_t), dimension(:), intent(in) :: prt_out
     type(model_t), pointer, intent(in) :: model
     type(var_list_t), intent(in) :: var_list
     integer, intent(in), optional :: nlo_type
     logical, intent(in), optional :: can_be_integrated
     type(string_t), dimension(:), allocatable :: prt_str_in
     type(string_t), dimension(:), allocatable :: prt_str_out
     class(prc_core_def_t), allocatable :: core_def
     type(string_t) :: method
     type(string_t) :: born_me_method
     type(string_t) :: real_tree_me_method
     type(string_t) :: loop_me_method
     type(string_t) :: correlation_me_method
     type(string_t) :: dglap_me_method
     integer :: i
     if (debug_on) call msg_debug2 (D_CORE, "process_configuration_setup_component")
     allocate (prt_str_in  (size (prt_in)))
     allocate (prt_str_out (size (prt_out)))
     forall (i = 1:size (prt_in))  prt_str_in(i)  = prt_in(i)% get_name ()
     forall (i = 1:size (prt_out)) prt_str_out(i) = prt_out(i)%get_name ()
 
     method = var_list%get_sval (var_str ("$method"))
     if (present (nlo_type)) then
        select case (nlo_type)
        case (BORN)
           born_me_method = var_list%get_sval (var_str ("$born_me_method"))
           if (born_me_method /= var_str ("")) then
              method = born_me_method
           end if
        case (NLO_VIRTUAL)
           loop_me_method = var_list%get_sval (var_str ("$loop_me_method"))
           if (loop_me_method /= var_str ("")) then
              method = loop_me_method
           end if
        case (NLO_REAL)
           real_tree_me_method = &
                var_list%get_sval (var_str ("$real_tree_me_method"))
           if (real_tree_me_method /= var_str ("")) then
              method = real_tree_me_method
           end if
        case (NLO_DGLAP)
           dglap_me_method = &
                var_list%get_sval (var_str ("$dglap_me_method"))
           if (dglap_me_method /= var_str ("")) then
              method = dglap_me_method
           end if
        case (NLO_SUBTRACTION,NLO_MISMATCH)
           correlation_me_method = &
                var_list%get_sval (var_str ("$correlation_me_method"))
           if (correlation_me_method /= var_str ("")) then
              method = correlation_me_method
           end if
        case default
        end select
     end if
     call dispatch_core_def (core_def, prt_str_in, prt_str_out, &
          model, var_list, config%id, nlo_type, method)
     select type (core_def)
     class is (prc_external_def_t)
        if (present (can_be_integrated)) then
           call core_def%set_active_writer (can_be_integrated)
        else
           call msg_fatal ("Cannot decide if external core is integrated!")
        end if
     end select
 
     if (debug_on) call msg_debug2 (D_CORE, "import_component with method ", method)
     call config%entry%import_component (i_component, &
          n_out = size (prt_out), &
          prt_in = prt_in, &
          prt_out = prt_out, &
          method = method, &
          variant = core_def, &
          nlo_type = nlo_type, &
          can_be_integrated = can_be_integrated)
   end subroutine process_configuration_setup_component
 
 @ %def process_configuration_setup_component
 @
 <<Process configurations: process configuration: TBP>>=
   procedure :: set_fixed_emitter => process_configuration_set_fixed_emitter
 <<Process configurations: procedures>>=
   subroutine process_configuration_set_fixed_emitter (config, i, emitter)
      class(process_configuration_t), intent(inout) :: config
      integer, intent(in) :: i, emitter
      call config%entry%set_fixed_emitter (i, emitter)
   end subroutine process_configuration_set_fixed_emitter
 
 @ %def process_configuration_set_fixed_emitter
 @
 <<Process configurations: process configuration: TBP>>=
   procedure :: set_coupling_powers => process_configuration_set_coupling_powers
 <<Process configurations: procedures>>=
   subroutine process_configuration_set_coupling_powers &
        (config, alpha_power, alphas_power)
     class(process_configuration_t), intent(inout) :: config
     integer, intent(in) :: alpha_power, alphas_power
     call config%entry%set_coupling_powers (alpha_power, alphas_power)
   end subroutine process_configuration_set_coupling_powers
 
 @ %def process_configuration_set_coupling_powers
 @
 <<Process configurations: process configuration: TBP>>=
   procedure :: set_component_associations => &
        process_configuration_set_component_associations
 <<Process configurations: procedures>>=
   subroutine process_configuration_set_component_associations &
          (config, i_list, remnant, use_real_finite, mismatch)
     class(process_configuration_t), intent(inout) :: config
     integer, dimension(:), intent(in) :: i_list
     logical, intent(in) :: remnant, use_real_finite, mismatch
     integer :: i_component
     do i_component = 1, config%entry%get_n_components ()
        if (any (i_list == i_component)) then
           call config%entry%set_associated_components (i_component, &
                i_list, remnant, use_real_finite, mismatch)
        end if
     end do
   end subroutine process_configuration_set_component_associations
 
 @ %def process_configuration_set_component_associations
 @ Record a process configuration: append it to the currently selected process
 definition library.
 <<Process configurations: process configuration: TBP>>=
   procedure :: record => process_configuration_record
 <<Process configurations: procedures>>=
   subroutine process_configuration_record (config, global)
     class(process_configuration_t), intent(inout) :: config
     type(rt_data_t), intent(inout) :: global
     if (associated (global%prclib)) then
        call global%prclib%open ()
        call global%prclib%append (config%entry)
        if (config%num_id /= 0) then
           write (msg_buffer, "(5A,I0,A)") "Process library '", &
                char (global%prclib%get_name ()), &
                "': recorded process '", char (config%id), "' (", &
                config%num_id, ")"
        else
           write (msg_buffer, "(5A)") "Process library '", &
                char (global%prclib%get_name ()), &
                "': recorded process '", char (config%id), "'"
        end if
        call msg_message ()
     else
        call msg_fatal ("Recording process '" // char (config%id) &
             // "': active process library undefined")
     end if
   end subroutine process_configuration_record
 
 @ %def process_configuration_record
 @
 \subsection{Unit Tests}
 Test module, followed by the corresponding implementation module.
 <<[[process_configurations_ut.f90]]>>=
 <<File header>>
 
 module process_configurations_ut
   use unit_tests
   use process_configurations_uti
 
 <<Standard module head>>
 
 <<Process configurations: public test>>
 
 <<Process configurations: public test auxiliary>>
 
 contains
 
 <<Process configurations: test driver>>
 
 end module process_configurations_ut
 @ %def process_configurations_ut
 @
 <<[[process_configurations_uti.f90]]>>=
 <<File header>>
 
 module process_configurations_uti
 
 <<Use strings>>
   use particle_specifiers, only: new_prt_spec
   use prclib_stacks
   use models
   use rt_data
 
   use process_configurations
 
 <<Standard module head>>
 
 <<Process configurations: test declarations>>
 
 <<Process configurations: public test auxiliary>>
 
 contains
 
 <<Process configurations: test auxiliary>>
 
 <<Process configurations: tests>>
 
 end module process_configurations_uti
 
 @ %def process_configurations_uti
 @ API: driver for the unit tests below.
 <<Process configurations: public test>>=
   public :: process_configurations_test
 <<Process configurations: test driver>>=
   subroutine process_configurations_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Process configurations: execute tests>>
   end subroutine process_configurations_test
 
 @ %def process_configurations_test
 @
 \subsubsection{Minimal setup}
 The workflow for setting up a minimal process configuration with the
 test matrix element method.
 
 We wrap this in a public procedure, so we can reuse it in later modules.
 The procedure prepares a process definition list for two processes
 (one [[prc_test]] and one [[omega]] type) and appends this to the
 process library stack in the global data set.
 
 The [[mode]] argument determines which processes to build.
 
 The [[procname]] argument replaces the predefined procname(s).
 
 This is re-exported by the UT module.
 <<Process configurations: public test auxiliary>>=
   public :: prepare_test_library
 <<Process configurations: test auxiliary>>=
   subroutine prepare_test_library (global, libname, mode, procname)
     type(rt_data_t), intent(inout), target :: global
     type(string_t), intent(in) :: libname
     integer, intent(in) :: mode
     type(string_t), intent(in), dimension(:), optional :: procname
     type(prclib_entry_t), pointer :: lib
     type(string_t) :: prc_name
     type(string_t), dimension(:), allocatable :: prt_in, prt_out
     integer :: n_components
     type(process_configuration_t) :: prc_config
 
     if (.not. associated (global%prclib_stack%get_first_ptr ())) then
        allocate (lib)
        call lib%init (libname)
        call global%add_prclib (lib)
     end if
 
     if (btest (mode, 0)) then
 
        call global%select_model (var_str ("Test"))
 
        if (present (procname)) then
           prc_name = procname(1)
        else
           prc_name = "prc_config_a"
        end if
        n_components = 1
        allocate (prt_in (2), prt_out (2))
        prt_in = [var_str ("s"), var_str ("s")]
        prt_out = [var_str ("s"), var_str ("s")]
 
        call global%set_string (var_str ("$method"),&
             var_str ("unit_test"), is_known = .true.)
 
        call prc_config%init (prc_name, &
             size (prt_in), n_components, &
             global%model, global%var_list)
        call prc_config%setup_component (1, &
             new_prt_spec (prt_in), new_prt_spec (prt_out), &
             global%model, global%var_list)
        call prc_config%record (global)
 
        deallocate (prt_in, prt_out)
 
     end if
 
     if (btest (mode, 1)) then
 
        call global%select_model (var_str ("QED"))
 
        if (present (procname)) then
           prc_name = procname(2)
        else
           prc_name = "prc_config_b"
        end if
        n_components = 1
        allocate (prt_in (2), prt_out (2))
        prt_in = [var_str ("e+"), var_str ("e-")]
        prt_out = [var_str ("m+"), var_str ("m-")]
 
        call global%set_string (var_str ("$method"),&
             var_str ("omega"), is_known = .true.)
 
        call prc_config%init (prc_name, &
             size (prt_in), n_components, &
             global%model, global%var_list)
        call prc_config%setup_component (1, &
             new_prt_spec (prt_in), new_prt_spec (prt_out), &
             global%model, global%var_list)
        call prc_config%record (global)
 
        deallocate (prt_in, prt_out)
 
     end if
 
     if (btest (mode, 2)) then
 
        call global%select_model (var_str ("Test"))
 
        if (present (procname)) then
           prc_name = procname(1)
        else
           prc_name = "prc_config_a"
        end if
        n_components = 1
        allocate (prt_in (1), prt_out (2))
        prt_in = [var_str ("s")]
        prt_out = [var_str ("f"), var_str ("fbar")]
 
        call global%set_string (var_str ("$method"),&
             var_str ("unit_test"), is_known = .true.)
 
        call prc_config%init (prc_name, &
             size (prt_in), n_components, &
             global%model, global%var_list)
        call prc_config%setup_component (1, &
             new_prt_spec (prt_in), new_prt_spec (prt_out), &
             global%model, global%var_list)
        call prc_config%record (global)
 
        deallocate (prt_in, prt_out)
 
     end if
 
   end subroutine prepare_test_library
 
 @ %def prepare_test_library
 @ The actual test: the previous procedure with some prelude and postlude.
 In the global variable list, just before printing we reset the
 variables where the value may depend on the system and run environment.
 <<Process configurations: execute tests>>=
   call test (process_configurations_1, "process_configurations_1", &
        "test processes", &
        u, results)
 <<Process configurations: test declarations>>=
   public :: process_configurations_1
 <<Process configurations: tests>>=
   subroutine process_configurations_1 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: process_configurations_1"
     write (u, "(A)")  "*   Purpose: configure test processes"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
 
     write (u, "(A)")  "* Configure processes as prc_test, model Test"
     write (u, "(A)")  "*                     and omega, model QED"
     write (u, *)
 
     call global%set_int (var_str ("process_num_id"), &
          42, is_known = .true.)
     call prepare_test_library (global, var_str ("prc_config_lib_1"), 3)
 
     global%os_data%fc = "Fortran-compiler"
     global%os_data%fcflags = "Fortran-flags"
 
     call global%write_libraries (u)
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: process_configurations_1"
 
   end subroutine process_configurations_1
 
 @ %def process_configurations_1
 @
 \subsubsection{\oMega\ options}
 Slightly extended example where we pass \oMega\ options to the
 library.  The [[prepare_test_library]] contents are spelled out.
 <<Process configurations: execute tests>>=
   call test (process_configurations_2, "process_configurations_2", &
        "omega options", &
        u, results)
 <<Process configurations: test declarations>>=
   public :: process_configurations_2
 <<Process configurations: tests>>=
   subroutine process_configurations_2 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
 
     type(string_t) :: libname
     type(prclib_entry_t), pointer :: lib
     type(string_t) :: prc_name
     type(string_t), dimension(:), allocatable :: prt_in, prt_out
     integer :: n_components
     type(process_configuration_t) :: prc_config
 
     write (u, "(A)")  "* Test output: process_configurations_2"
     write (u, "(A)")  "*   Purpose: configure test processes with options"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
 
     write (u, "(A)")  "* Configure processes as omega, model QED"
     write (u, *)
 
     libname = "prc_config_lib_2"
 
     allocate (lib)
     call lib%init (libname)
     call global%add_prclib (lib)
 
     call global%select_model (var_str ("QED"))
 
     prc_name = "prc_config_c"
     n_components = 2
     allocate (prt_in (2), prt_out (2))
     prt_in = [var_str ("e+"), var_str ("e-")]
     prt_out = [var_str ("m+"), var_str ("m-")]
 
     call global%set_string (var_str ("$method"),&
          var_str ("omega"), is_known = .true.)
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
 
     call prc_config%init (prc_name, size (prt_in), n_components, &
          global%model, global%var_list)
 
     call global%set_log (var_str ("?report_progress"), &
          .true., is_known = .true.)
     call prc_config%setup_component (1, &
          new_prt_spec (prt_in), new_prt_spec (prt_out), global%model, global%var_list)
 
     call global%set_log (var_str ("?report_progress"), &
          .false., is_known = .true.)
     call global%set_log (var_str ("?omega_openmp"), &
          .true., is_known = .true.)
     call global%set_string (var_str ("$restrictions"),&
          var_str ("3+4~A"), is_known = .true.)
     call global%set_string (var_str ("$omega_flags"), &
          var_str ("-fusion:progress_file omega_prc_config.log"), &
          is_known = .true.)
     call prc_config%setup_component (2, &
          new_prt_spec (prt_in), new_prt_spec (prt_out), global%model, global%var_list)
 
     call prc_config%record (global)
 
     deallocate (prt_in, prt_out)
 
     global%os_data%fc = "Fortran-compiler"
     global%os_data%fcflags = "Fortran-flags"
 
     call global%write_vars (u, [ &
          var_str ("$model_name"), &
          var_str ("$method"), &
          var_str ("?report_progress"), &
          var_str ("$restrictions"), &
          var_str ("$omega_flags")])
     write (u, "(A)")
     call global%write_libraries (u)
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: process_configurations_2"
 
   end subroutine process_configurations_2
 
 @ %def process_configurations_2
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Compilation}
 This module manages compilation and loading of of process libraries.  It is
 needed as a separate module because integration depends on it.
 <<[[compilations.f90]]>>=
 <<File header>>
 
 module compilations
 
 <<Use strings>>
   use io_units
   use system_defs, only: TAB
   use diagnostics
   use os_interface
   use variables, only: var_list_t
   use model_data
   use process_libraries
   use prclib_stacks
   use rt_data
 
 <<Standard module head>>
 
 <<Compilations: public>>
 
 <<Compilations: types>>
 
 <<Compilations: parameters>>
 
 contains
 
 <<Compilations: procedures>>
 
 end module compilations
 @ %def compilations
 @
 \subsection{The data type}
 The compilation item handles the compilation and loading of a single
 process library.
 <<Compilations: public>>=
   public :: compilation_item_t
 <<Compilations: types>>=
   type :: compilation_item_t
      private
      type(string_t) :: libname
      type(string_t) :: static_external_tag
      type(process_library_t), pointer :: lib => null ()
      logical :: recompile_library = .false.
      logical :: verbose = .false.
      logical :: use_workspace = .false.
      type(string_t) :: workspace
    contains
    <<Compilations: compilation item: TBP>>
   end type compilation_item_t
 
 @ %def compilation_item_t
 @ Initialize.
 
 Set flags and global properties of the library.  Establish the workspace name,
 if defined.
 <<Compilations: compilation item: TBP>>=
   procedure :: init => compilation_item_init
 <<Compilations: procedures>>=
   subroutine compilation_item_init (comp, libname, stack, var_list)
     class(compilation_item_t), intent(out) :: comp
     type(string_t), intent(in) :: libname
     type(prclib_stack_t), intent(inout) :: stack
     type(var_list_t), intent(in) :: var_list
     comp%libname = libname
     comp%lib => stack%get_library_ptr (comp%libname)
     if (.not. associated (comp%lib)) then
        call msg_fatal ("Process library '" // char (comp%libname) &
             // "' has not been declared.")
     end if
     comp%recompile_library = &
          var_list%get_lval (var_str ("?recompile_library"))
     comp%verbose = &
          var_list%get_lval (var_str ("?me_verbose"))
     comp%use_workspace = &
          var_list%is_known (var_str ("$compile_workspace"))
     if (comp%use_workspace) then
        comp%workspace = &
             var_list%get_sval (var_str ("$compile_workspace"))
        if (comp%workspace == "")  comp%use_workspace = .false.
     else
        comp%workspace = ""
     end if
   end subroutine compilation_item_init
 
 @ %def compilation_item_init
 @ Compile the current library.  The [[force]] flag has the
 effect that we first delete any previous files, as far as accessible
 by the current makefile.  It also guarantees that previous files not
 accessible by a makefile will be overwritten.
 <<Compilations: compilation item: TBP>>=
   procedure :: compile => compilation_item_compile
 <<Compilations: procedures>>=
   subroutine compilation_item_compile (comp, model, os_data, force, recompile)
     class(compilation_item_t), intent(inout) :: comp
     class(model_data_t), intent(in), target :: model
     type(os_data_t), intent(in) :: os_data
     logical, intent(in) :: force, recompile
     if (associated (comp%lib)) then
        if (comp%use_workspace)  call setup_workspace (comp%workspace, os_data)
        call msg_message ("Process library '" &
             // char (comp%libname) // "': compiling ...")
        call comp%lib%configure (os_data)
        if (signal_is_pending ())  return
        call comp%lib%compute_md5sum (model)
        call comp%lib%write_makefile &
             (os_data, force, verbose=comp%verbose, workspace=comp%workspace)
        if (signal_is_pending ())  return
        if (force) then
           call comp%lib%clean &
                (os_data, distclean = .false., workspace=comp%workspace)
           if (signal_is_pending ())  return
        end if
        call comp%lib%write_driver (force, workspace=comp%workspace)
        if (signal_is_pending ())  return
        if (recompile) then
           call comp%lib%load &
                (os_data, keep_old_source = .true., workspace=comp%workspace)
           if (signal_is_pending ())  return
        end if
        call comp%lib%update_status (os_data, workspace=comp%workspace)
     end if
   end subroutine compilation_item_compile
 
 @ %def compilation_item_compile
 @ The workspace directory is created if it does not exist.  (Applies only if
 the use has set the workspace directory.)
 <<Compilations: parameters>>=
   character(*), parameter :: ALLOWED_IN_DIRNAME = &
        "abcdefghijklmnopqrstuvwxyz&
        &ABCDEFGHIJKLMNOPQRSTUVWXYZ&
        &1234567890&
        &.,_-+="
 @ %def ALLOWED_IN_DIRNAME
 <<Compilations: procedures>>=
   subroutine setup_workspace (workspace, os_data)
     type(string_t), intent(in) :: workspace
     type(os_data_t), intent(in) :: os_data
     if (verify (workspace, ALLOWED_IN_DIRNAME) == 0) then
        call msg_message ("Compile: preparing workspace directory '" &
             // char (workspace) // "'")
        call os_system_call ("mkdir -p '" // workspace // "'")
     else
        call msg_fatal ("compile: workspace name '" &
             // char (workspace) // "' contains illegal characters")
     end if
   end subroutine setup_workspace
 
 @ %def setup_workspace
 @ Load the current library, just after compiling it.
 <<Compilations: compilation item: TBP>>=
   procedure :: load => compilation_item_load
 <<Compilations: procedures>>=
   subroutine compilation_item_load (comp, os_data)
     class(compilation_item_t), intent(inout) :: comp
     type(os_data_t), intent(in) :: os_data
     if (associated (comp%lib)) then
        call comp%lib%load (os_data, workspace=comp%workspace)
     end if
   end subroutine compilation_item_load
 
 @ %def compilation_item_load
 @ Message as a separate call:
 <<Compilations: compilation item: TBP>>=
   procedure :: success => compilation_item_success
 <<Compilations: procedures>>=
   subroutine compilation_item_success (comp)
     class(compilation_item_t), intent(in) :: comp
     if (associated (comp%lib)) then
        call msg_message ("Process library '" // char (comp%libname) &
             // "': ... success.")
     else
        call msg_fatal ("Process library '" // char (comp%libname) &
             // "': ... failure.")
     end if
   end subroutine compilation_item_success
 
 @ %def compilation_item_success
 @ %def compilation_item_failure
 @
 \subsection{API for library compilation and loading}
 This is a shorthand for compiling and loading a single library.  The
 [[compilation_item]] object is used only internally.
 
 The [[global]] data set may actually be local to the caller.  The
 compilation affects the library specified by its name if it is on the
 stack, but it does not reset the currently selected library.
 <<Compilations: public>>=
   public :: compile_library
 <<Compilations: procedures>>=
   subroutine compile_library (libname, global)
     type(string_t), intent(in) :: libname
     type(rt_data_t), intent(inout), target :: global
     type(compilation_item_t) :: comp
     logical :: force, recompile
     force = &
          global%var_list%get_lval (var_str ("?rebuild_library"))
     recompile = &
          global%var_list%get_lval (var_str ("?recompile_library"))
     if (associated (global%model)) then
        call comp%init (libname, global%prclib_stack, global%var_list)
        call comp%compile (global%model, global%os_data, force, recompile)
        if (signal_is_pending ())  return
        call comp%load (global%os_data)
        if (signal_is_pending ())  return
     else
        call msg_fatal ("Process library compilation: " &
             // " model is undefined.")
     end if
     call comp%success ()
   end subroutine compile_library
 
 @ %def compile_library
 @
 \subsection{Compiling static executable}
 This object handles the creation of a static executable which should
 contain a set of static process libraries.
 <<Compilations: public>>=
   public :: compilation_t
 <<Compilations: types>>=
   type :: compilation_t
      private
      type(string_t) :: exe_name
      type(string_t), dimension(:), allocatable :: lib_name
    contains
    <<Compilations: compilation: TBP>>
   end type compilation_t
 
 @ %def compilation_t
 @ Output.
 <<Compilations: compilation: TBP>>=
   procedure :: write => compilation_write
 <<Compilations: procedures>>=
   subroutine compilation_write (object, unit)
     class(compilation_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer :: u, i
     u = given_output_unit (unit)
     write (u, "(1x,A)")  "Compilation object:"
     write (u, "(3x,3A)")  "executable        = '", &
          char (object%exe_name), "'"
     write (u, "(3x,A)", advance="no")  "process libraries ="
     do i = 1, size (object%lib_name)
        write (u, "(1x,3A)", advance="no")  "'", char (object%lib_name(i)), "'"
     end do
     write (u, *)
   end subroutine compilation_write
 
 @ %def compilation_write
 @ Initialize: we know the names of the executable and of the libraries.
 Optionally, we may provide a workspace directory.
 <<Compilations: compilation: TBP>>=
   procedure :: init => compilation_init
 <<Compilations: procedures>>=
   subroutine compilation_init (compilation, exe_name, lib_name)
     class(compilation_t), intent(out) :: compilation
     type(string_t), intent(in) :: exe_name
     type(string_t), dimension(:), intent(in) :: lib_name
     compilation%exe_name = exe_name
     allocate (compilation%lib_name (size (lib_name)))
     compilation%lib_name = lib_name
   end subroutine compilation_init
 
 @ %def compilation_init
 @ Write the dispatcher subroutine for the compiled libraries.  Also
 write a subroutine which returns the names of the compiled libraries.
 <<Compilations: compilation: TBP>>=
   procedure :: write_dispatcher => compilation_write_dispatcher
 <<Compilations: procedures>>=
   subroutine compilation_write_dispatcher (compilation)
     class(compilation_t), intent(in) :: compilation
     type(string_t) :: file
     integer :: u, i
     file = compilation%exe_name // "_prclib_dispatcher.f90"
     call msg_message ("Static executable '" // char (compilation%exe_name) &
          // "': writing library dispatcher")
     u = free_unit ()
     open (u, file = char (file), status="replace", action="write")
     write (u, "(3A)")  "! Whizard: process libraries for executable '", &
          char (compilation%exe_name), "'"
     write (u, "(A)")  "! Automatically generated file, do not edit"
     write (u, "(A)")  "subroutine dispatch_prclib_static " // &
          "(driver, basename, modellibs_ldflags)"
     write (u, "(A)")  "  use iso_varying_string, string_t => varying_string"
     write (u, "(A)")  "  use prclib_interfaces"
     do i = 1, size (compilation%lib_name)
        associate (lib_name => compilation%lib_name(i))
          write (u, "(A)")  "  use " // char (lib_name) // "_driver"
        end associate
     end do
     write (u, "(A)")  "  implicit none"
     write (u, "(A)")  "  class(prclib_driver_t), intent(inout), allocatable &
          &:: driver"
     write (u, "(A)")  "  type(string_t), intent(in) :: basename"
     write (u, "(A)")  "  logical, intent(in), optional :: " // &
          "modellibs_ldflags"
     write (u, "(A)")  "  select case (char (basename))"
     do i = 1, size (compilation%lib_name)
        associate (lib_name => compilation%lib_name(i))
          write (u, "(3A)")  "  case ('", char (lib_name), "')"
          write (u, "(3A)")  "     allocate (", char (lib_name), "_driver_t &
               &:: driver)"
        end associate
     end do
     write (u, "(A)")  "  end select"
     write (u, "(A)")  "end subroutine dispatch_prclib_static"
     write (u, *)
     write (u, "(A)")  "subroutine get_prclib_static (libname)"
     write (u, "(A)")  "  use iso_varying_string, string_t => varying_string"
     write (u, "(A)")  "  implicit none"
     write (u, "(A)")  "  type(string_t), dimension(:), intent(inout), &
          &allocatable :: libname"
     write (u, "(A,I0,A)")  "  allocate (libname (", &
          size (compilation%lib_name), "))"
     do i = 1, size (compilation%lib_name)
        associate (lib_name => compilation%lib_name(i))
          write (u, "(A,I0,A,A,A)")  "  libname(", i, ") = '", &
               char (lib_name), "'"
        end associate
     end do
     write (u, "(A)")  "end subroutine get_prclib_static"
     close (u)
   end subroutine compilation_write_dispatcher
 
 @ %def compilation_write_dispatcher
 @ Write the Makefile subroutine for the compiled libraries.
 <<Compilations: compilation: TBP>>=
   procedure :: write_makefile => compilation_write_makefile
 <<Compilations: procedures>>=
   subroutine compilation_write_makefile &
        (compilation, os_data, ext_libtag, verbose)
     class(compilation_t), intent(in) :: compilation
     type(os_data_t), intent(in) :: os_data
     logical, intent(in) :: verbose
     type(string_t), intent(in), optional :: ext_libtag
     type(string_t) :: file, ext_tag
     integer :: u, i
     if (present (ext_libtag)) then
        ext_tag = ext_libtag
     else
        ext_tag = ""
     end if
     file = compilation%exe_name // ".makefile"
     call msg_message ("Static executable '" // char (compilation%exe_name) &
          // "': writing makefile")
     u = free_unit ()
     open (u, file = char (file), status="replace", action="write")
     write (u, "(3A)")  "# WHIZARD: Makefile for executable '", &
          char (compilation%exe_name), "'"
     write (u, "(A)")  "# Automatically generated file, do not edit"
     write (u, "(A)") ""
     write (u, "(A)") "# Executable name"
     write (u, "(A)") "EXE = " // char (compilation%exe_name)
     write (u, "(A)") ""
     write (u, "(A)") "# Compiler"
     write (u, "(A)") "FC = " // char (os_data%fc)
     write (u, "(A)") ""
     write (u, "(A)") "# Included libraries"
     write (u, "(A)") "FCINCL = " // char (os_data%whizard_includes)
     write (u, "(A)") ""
     write (u, "(A)") "# Compiler flags"
     write (u, "(A)") "FCFLAGS = " // char (os_data%fcflags)
     write (u, "(A)") "LDFLAGS = " // char (os_data%ldflags)
     write (u, "(A)") "LDFLAGS_STATIC = " // char (os_data%ldflags_static)
     write (u, "(A)") "LDFLAGS_HEPMC = " // char (os_data%ldflags_hepmc)
     write (u, "(A)") "LDFLAGS_LCIO = " // char (os_data%ldflags_lcio)
     write (u, "(A)") "LDFLAGS_HOPPET = " // char (os_data%ldflags_hoppet)
     write (u, "(A)") "LDFLAGS_LOOPTOOLS = " // char (os_data%ldflags_looptools)
     write (u, "(A)") "LDWHIZARD = " // char (os_data%whizard_ldflags)
     write (u, "(A)") ""
     write (u, "(A)") "# Libtool"
     write (u, "(A)") "LIBTOOL = " // char (os_data%whizard_libtool)
     if (verbose) then
        write (u, "(A)") "FCOMPILE = $(LIBTOOL) --tag=FC --mode=compile"
        write (u, "(A)") "LINK = $(LIBTOOL) --tag=FC --mode=link"
     else
        write (u, "(A)") "FCOMPILE = @$(LIBTOOL) --silent --tag=FC --mode=compile"
        write (u, "(A)") "LINK = @$(LIBTOOL) --silent --tag=FC --mode=link"
     end if
     write (u, "(A)") ""
     write (u, "(A)") "# Compile commands (default)"
     write (u, "(A)") "LTFCOMPILE = $(FCOMPILE) $(FC) -c $(FCINCL) $(FCFLAGS)"
     write (u, "(A)") ""
     write (u, "(A)") "# Default target"
     write (u, "(A)") "all: link"
     write (u, "(A)") ""
     write (u, "(A)") "# Libraries"
     do i = 1, size (compilation%lib_name)
        associate (lib_name => compilation%lib_name(i))
          write (u, "(A)") "LIBRARIES += " // char (lib_name) // ".la"
          write (u, "(A)") char (lib_name) // ".la:"
          write (u, "(A)") TAB // "$(MAKE) -f " // char (lib_name) // ".makefile"
        end associate
     end do
     write (u, "(A)") ""
     write (u, "(A)") "# Library dispatcher"
     write (u, "(A)") "DISP = $(EXE)_prclib_dispatcher"
     write (u, "(A)") "$(DISP).lo: $(DISP).f90 $(LIBRARIES)"
     if (.not. verbose) then
        write (u, "(A)")  TAB // '@echo  "  FC       " $@'
     end if
     write (u, "(A)") TAB // "$(LTFCOMPILE) $<"
     write (u, "(A)") ""
     write (u, "(A)") "# Executable"
     write (u, "(A)") "$(EXE): $(DISP).lo $(LIBRARIES)"
     if (.not. verbose) then
        write (u, "(A)")  TAB // '@echo  "  FCLD     " $@'
     end if
     write (u, "(A)") TAB // "$(LINK) $(FC) -static $(FCFLAGS) \"
     write (u, "(A)") TAB // "   $(LDWHIZARD) $(LDFLAGS) \"
     write (u, "(A)") TAB // "   -o $(EXE) $^ \"
     write (u, "(A)") TAB // "   $(LDFLAGS_HEPMC) $(LDFLAGS_LCIO) $(LDFLAGS_HOPPET) \"
     write (u, "(A)") TAB // "   $(LDFLAGS_LOOPTOOLS) $(LDFLAGS_STATIC)" // char (ext_tag)
     write (u, "(A)") ""
     write (u, "(A)") "# Main targets"
     write (u, "(A)") "link: compile $(EXE)"
     write (u, "(A)") "compile: $(LIBRARIES) $(DISP).lo"
     write (u, "(A)") ".PHONY: link compile"
     write (u, "(A)") ""
     write (u, "(A)") "# Cleanup targets"
     write (u, "(A)") "clean-exe:"
     write (u, "(A)") TAB // "rm -f $(EXE)"
     write (u, "(A)") "clean-objects:"
     write (u, "(A)") TAB // "rm -f $(DISP).lo"
     write (u, "(A)") "clean-source:"
     write (u, "(A)") TAB // "rm -f $(DISP).f90"
     write (u, "(A)") "clean-makefile:"
     write (u, "(A)") TAB // "rm -f $(EXE).makefile"
     write (u, "(A)") ""
     write (u, "(A)") "clean: clean-exe clean-objects clean-source"
     write (u, "(A)") "distclean: clean clean-makefile"
     write (u, "(A)") ".PHONY: clean distclean"
     close (u)
   end subroutine compilation_write_makefile
 
 @ %def compilation_write_makefile
 @ Compile the dispatcher source code.
 <<Compilations: compilation: TBP>>=
   procedure :: make_compile => compilation_make_compile
 <<Compilations: procedures>>=
   subroutine compilation_make_compile (compilation, os_data)
     class(compilation_t), intent(in) :: compilation
     type(os_data_t), intent(in) :: os_data
     call os_system_call ("make compile " // os_data%makeflags &
          // " -f " // compilation%exe_name // ".makefile")
   end subroutine compilation_make_compile
 
 @ %def compilation_make_compile
 @ Link the dispatcher together with all matrix-element code and the
 \whizard\ and \oMega\ main libraries, to generate a static executable.
 <<Compilations: compilation: TBP>>=
   procedure :: make_link => compilation_make_link
 <<Compilations: procedures>>=
   subroutine compilation_make_link (compilation, os_data)
     class(compilation_t), intent(in) :: compilation
     type(os_data_t), intent(in) :: os_data
     call os_system_call ("make link " // os_data%makeflags &
          // " -f " // compilation%exe_name // ".makefile")
   end subroutine compilation_make_link
 
 @ %def compilation_make_link
 @ Cleanup.
 <<Compilations: compilation: TBP>>=
   procedure :: make_clean_exe => compilation_make_clean_exe
 <<Compilations: procedures>>=
   subroutine compilation_make_clean_exe (compilation, os_data)
     class(compilation_t), intent(in) :: compilation
     type(os_data_t), intent(in) :: os_data
     call os_system_call ("make clean-exe " // os_data%makeflags &
          // " -f " // compilation%exe_name // ".makefile")
   end subroutine compilation_make_clean_exe
 
 @ %def compilation_make_clean_exe
 @
 \subsection{API for executable compilation}
 This is a shorthand for compiling and loading an executable, including
 the enclosed libraries.  The [[compilation]] object is used only internally.
 
 The [[global]] data set may actually be local to the caller.  The
 compilation affects the library specified by its name if it is on the
 stack, but it does not reset the currently selected library.
 <<Compilations: public>>=
   public :: compile_executable
 <<Compilations: procedures>>=
   subroutine compile_executable (exename, libname, global)
     type(string_t), intent(in) :: exename
     type(string_t), dimension(:), intent(in) :: libname
     type(rt_data_t), intent(inout), target :: global
     type(compilation_t) :: compilation
     type(compilation_item_t) :: item
     type(string_t) :: ext_libtag
     logical :: force, recompile, verbose
     integer :: i
     ext_libtag = ""
     force = &
          global%var_list%get_lval (var_str ("?rebuild_library"))
     recompile = &
          global%var_list%get_lval (var_str ("?recompile_library"))
     verbose = &
          global%var_list%get_lval (var_str ("?me_verbose"))
     call compilation%init (exename, [libname])
     if (signal_is_pending ())  return
     call compilation%write_dispatcher ()
     if (signal_is_pending ())  return
     do i = 1, size (libname)
        call item%init (libname(i), global%prclib_stack, global%var_list)
        call item%compile (global%model, global%os_data, &
             force=force, recompile=recompile)
        ext_libtag = "" // item%lib%get_static_modelname (global%os_data)
        if (signal_is_pending ())  return
        call item%success ()
     end do
     call compilation%write_makefile &
          (global%os_data, ext_libtag=ext_libtag, verbose=verbose)
     if (signal_is_pending ())  return
     call compilation%make_compile (global%os_data)
     if (signal_is_pending ())  return
     call compilation%make_link (global%os_data)
   end subroutine compile_executable
 
 @ %def compile_executable
 @
 \subsection{Unit Tests}
 Test module, followed by the stand-alone unit-test procedures.
 <<[[compilations_ut.f90]]>>=
 <<File header>>
 
 module compilations_ut
   use unit_tests
   use compilations_uti
 
 <<Standard module head>>
 
 <<Compilations: public test>>
 
 contains
 
 <<Compilations: test driver>>
 
 end module compilations_ut
 @ %def compilations_ut
 @
 <<[[compilations_uti.f90]]>>=
 <<File header>>
 
 module compilations_uti
 
 <<Use strings>>
   use io_units
   use models
   use rt_data
   use process_configurations_ut, only: prepare_test_library
 
   use compilations
 
 <<Standard module head>>
 
 <<Compilations: test declarations>>
 
 contains
 
 <<Compilations: tests>>
 
 end module compilations_uti
 
 @ %def compilations_uti
 @ API: driver for the unit tests below.
 <<Compilations: public test>>=
   public :: compilations_test
 <<Compilations: test driver>>=
   subroutine compilations_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Compilations: execute tests>>
 end subroutine compilations_test
 
 @ %def compilations_test
 @
 \subsubsection{Intrinsic Matrix Element}
 Compile an intrinsic test matrix element ([[prc_test]] type).
 
 Note: In this and the following test, we reset the Fortran compiler and flag
 variables immediately before they are printed, so the test is portable.
 <<Compilations: execute tests>>=
   call test (compilations_1, "compilations_1", &
        "intrinsic test processes", &
        u, results)
 <<Compilations: test declarations>>=
   public :: compilations_1
 <<Compilations: tests>>=
   subroutine compilations_1 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: compilations_1"
     write (u, "(A)")  "*   Purpose: configure and compile test process"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
 
     libname = "compilation_1"
     procname = "prc_comp_1"
     call prepare_test_library (global, libname, 1, [procname])
 
     call compile_library (libname, global)
 
     call global%write_libraries (u)
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: compilations_1"
 
   end subroutine compilations_1
 
 @ %def compilations_1
 @
 \subsubsection{External Matrix Element}
 Compile an external test matrix element ([[omega]] type)
 <<Compilations: execute tests>>=
   call test (compilations_2, "compilations_2", &
        "external process (omega)", &
        u, results)
 <<Compilations: test declarations>>=
   public :: compilations_2
 <<Compilations: tests>>=
   subroutine compilations_2 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: compilations_2"
     write (u, "(A)")  "*   Purpose: configure and compile test process"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
 
     libname = "compilation_2"
     procname = "prc_comp_2"
     call prepare_test_library (global, libname, 2, [procname,procname])
 
     call compile_library (libname, global)
 
     call global%write_libraries (u, libpath = .false.)
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: compilations_2"
 
   end subroutine compilations_2
 
 @ %def compilations_2
 @
 \subsubsection{External Matrix Element}
 Compile an external test matrix element ([[omega]] type) and
 create driver files for a static executable.
 <<Compilations: execute tests>>=
   call test (compilations_3, "compilations_3", &
        "static executable: driver", &
        u, results)
 <<Compilations: test declarations>>=
   public :: compilations_3
 <<Compilations: tests>>=
   subroutine compilations_3 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname, exename
     type(rt_data_t), target :: global
     type(compilation_t) :: compilation
     integer :: u_file
     character(80) :: buffer
 
     write (u, "(A)")  "* Test output: compilations_3"
     write (u, "(A)")  "*   Purpose: make static executable"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize library"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
 
     libname = "compilations_3_lib"
     procname = "prc_comp_3"
     exename = "compilations_3"
 
     call prepare_test_library (global, libname, 2, [procname,procname])
 
     call compilation%init (exename, [libname])
     call compilation%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write dispatcher"
     write (u, "(A)")
 
     call compilation%write_dispatcher ()
 
     u_file = free_unit ()
     open (u_file, file = char (exename) // "_prclib_dispatcher.f90", &
          status = "old", action = "read")
     do
        read (u_file, "(A)", end = 1)  buffer
        write (u, "(A)")  trim (buffer)
     end do
 1   close (u_file)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write Makefile"
     write (u, "(A)")
 
     associate (os_data => global%os_data)
       os_data%fc = "fortran-compiler"
       os_data%whizard_includes = "my-includes"
       os_data%fcflags = "my-fcflags"
       os_data%ldflags = "my-ldflags"
       os_data%ldflags_static = "my-ldflags-static"
       os_data%ldflags_hepmc = "my-ldflags-hepmc"
       os_data%ldflags_lcio = "my-ldflags-lcio"
       os_data%ldflags_hoppet = "my-ldflags-hoppet"
       os_data%ldflags_looptools = "my-ldflags-looptools"
       os_data%whizard_ldflags = "my-ldwhizard"
       os_data%whizard_libtool = "my-libtool"
     end associate
 
     call compilation%write_makefile (global%os_data, verbose = .true.)
 
     open (u_file, file = char (exename) // ".makefile", &
          status = "old", action = "read")
     do
        read (u_file, "(A)", end = 2)  buffer
        write (u, "(A)")  trim (buffer)
     end do
 2   close (u_file)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: compilations_3"
 
   end subroutine compilations_3
 
 @ %def compilations_3
 @
 \subsection{Test static build}
 The tests for building a static executable are separate, since they
 should be skipped if the \whizard\ build itself has static libraries
 disabled.
 <<Compilations: public test>>=
   public :: compilations_static_test
 <<Compilations: test driver>>=
   subroutine compilations_static_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Compilations: static tests>>
 end subroutine compilations_static_test
 
 @ %def compilations_static_test
 @
 \subsubsection{External Matrix Element}
 Compile an external test matrix element ([[omega]] type) and
 incorporate this in a new static WHIZARD executable.
 <<Compilations: static tests>>=
   call test (compilations_static_1, "compilations_static_1", &
        "static executable: compilation", &
        u, results)
 <<Compilations: test declarations>>=
   public :: compilations_static_1
 <<Compilations: tests>>=
   subroutine compilations_static_1 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname, exename
     type(rt_data_t), target :: global
     type(compilation_item_t) :: item
     type(compilation_t) :: compilation
     logical :: exist
 
     write (u, "(A)")  "* Test output: compilations_static_1"
     write (u, "(A)")  "*   Purpose: make static executable"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize library"
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
 
     libname = "compilations_static_1_lib"
     procname = "prc_comp_stat_1"
     exename = "compilations_static_1"
 
     call prepare_test_library (global, libname, 2, [procname,procname])
 
     call compilation%init (exename, [libname])
 
     write (u, "(A)")
     write (u, "(A)")  "* Write dispatcher"
 
     call compilation%write_dispatcher ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Write Makefile"
 
     call compilation%write_makefile (global%os_data, verbose = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build libraries"
 
     call item%init (libname, global%prclib_stack, global%var_list)
     call item%compile &
          (global%model, global%os_data, force=.true., recompile=.false.)
     call item%success ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Check executable (should be absent)"
     write (u, "(A)")
 
     call compilation%make_clean_exe (global%os_data)
     inquire (file = char (exename), exist = exist)
     write (u, "(A,A,L1)")  char (exename), " exists = ", exist
 
     write (u, "(A)")
     write (u, "(A)")  "* Build executable"
     write (u, "(A)")
 
     call compilation%make_compile (global%os_data)
     call compilation%make_link (global%os_data)
 
     write (u, "(A)")  "* Check executable (should be present)"
     write (u, "(A)")
 
     inquire (file = char (exename), exist = exist)
     write (u, "(A,A,L1)")  char (exename), " exists = ", exist
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call compilation%make_clean_exe (global%os_data)
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: compilations_static_1"
 
   end subroutine compilations_static_1
 
 @ %def compilations_static_1
 @
 \subsubsection{External Matrix Element}
 Compile an external test matrix element ([[omega]] type) and
 incorporate this in a new static WHIZARD executable.  In this version,
 we use the wrapper [[compile_executable]] procedure.
 <<Compilations: static tests>>=
   call test (compilations_static_2, "compilations_static_2", &
        "static executable: shortcut", &
        u, results)
 <<Compilations: test declarations>>=
   public :: compilations_static_2
 <<Compilations: tests>>=
   subroutine compilations_static_2 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname, exename
     type(rt_data_t), target :: global
     logical :: exist
     integer :: u_file
 
     write (u, "(A)")  "* Test output: compilations_static_2"
     write (u, "(A)")  "*   Purpose: make static executable"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize library and compile"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
 
     libname = "compilations_static_2_lib"
     procname = "prc_comp_stat_2"
     exename = "compilations_static_2"
 
     call prepare_test_library (global, libname, 2, [procname,procname])
 
     call compile_executable (exename, [libname], global)
 
     write (u, "(A)")  "* Check executable (should be present)"
     write (u, "(A)")
 
     inquire (file = char (exename), exist = exist)
     write (u, "(A,A,L1)")  char (exename), " exists = ", exist
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     u_file = free_unit ()
     open (u_file, file = char (exename), status = "old", action = "write")
     close (u_file, status = "delete")
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: compilations_static_2"
 
   end subroutine compilations_static_2
 
 @ %def compilations_static_2
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Integration}
 This module manages phase space setup, matrix-element evaluation and
 integration, as far as it is not done by lower-level routines, in particular
 in the [[processes]] module.
 <<[[integrations.f90]]>>=
 <<File header>>
 
 module integrations
 
 <<Use kinds>>
 <<Use strings>>
 <<Use debug>>
   use io_units
   use diagnostics
   use os_interface
   use cputime
   use sm_qcd
   use physics_defs
   use model_data
   use pdg_arrays
   use variables, only: var_list_t
   use eval_trees
   use sf_mappings
   use sf_base
   use phs_base
   use rng_base
   use mci_base
   use process_libraries
   use prc_core
   use process_config, only: COMP_MASTER, COMP_REAL_FIN, &
        COMP_MISMATCH, COMP_PDF, COMP_REAL, COMP_SUB, COMP_VIRT, &
        COMP_REAL_SING
   use process
   use pcm_base, only: pcm_t
   use instances
   use process_stacks
   use models
   use iterations
   use rt_data
 
   use dispatch_me_methods, only: dispatch_core
   use dispatch_beams, only: dispatch_qcd, sf_prop_t, dispatch_sf_config
   use dispatch_phase_space, only: dispatch_sf_channels
   use dispatch_phase_space, only: dispatch_phs
   use dispatch_mci, only: dispatch_mci_s, setup_grid_path
   use dispatch_transforms, only: dispatch_evt_shower_hook
 
   use compilations, only: compile_library
 
   use dispatch_fks, only: dispatch_fks_s
   use nlo_data
 <<Use mpi f08>>
 
 <<Standard module head>>
 
 <<Integrations: public>>
 
 <<Integrations: types>>
 
 contains
 
 <<Integrations: procedures>>
 
 end module integrations
 @ %def integrations
 @
 \subsection{The integration type}
 This type holds all relevant data, the integration methods operates on this.
 In contrast to the [[simulation_t]] introduced later, the [[integration_t]]
 applies to a single process.
 <<Integrations: public>>=
   public :: integration_t
 <<Integrations: types>>=
   type :: integration_t
     private
     type(string_t) :: process_id
     type(string_t) :: run_id
     type(process_t), pointer :: process => null ()
     logical :: rebuild_phs = .false.
     logical :: ignore_phs_mismatch = .false.
     logical :: phs_only = .false.
     logical :: process_has_me = .true.
     integer :: n_calls_test = 0
     logical :: vis_history = .true.
     type(string_t) :: history_filename
     type(string_t) :: log_filename
     type(helicity_selection_t) :: helicity_selection
     logical :: use_color_factors = .false.
     logical :: has_beam_pol = .false.
     logical :: combined_integration = .false.
     type(iteration_multipliers_t) :: iteration_multipliers
     type(nlo_settings_t) :: nlo_settings
    contains
    <<Integrations: integration: TBP>>
   end type integration_t
 
 @ %def integration_t
 @
 @
 \subsection{Initialization}
 Initialization, first part: Create a process entry.
 Push it on the stack if the [[global]] environment is supplied.
 <<Integrations: integration: TBP>>=
   procedure :: create_process => integration_create_process
 <<Integrations: procedures>>=
   subroutine integration_create_process (intg, process_id, global)
     class(integration_t), intent(out) :: intg
     type(rt_data_t), intent(inout), optional, target :: global
     type(string_t), intent(in) :: process_id
     type(process_entry_t), pointer :: process_entry
     if (debug_on) call msg_debug (D_CORE, "integration_create_process")
     intg%process_id = process_id
     if (present (global)) then
        allocate (process_entry)
        intg%process => process_entry%process_t
        call global%process_stack%push (process_entry)
     else
        allocate (process_t :: intg%process)
     end if
   end subroutine integration_create_process
 
 @ %def integration_create_process
 @ Initialization, second part: Initialize the process object, using the local
 environment.  We allocate a RNG factory and a QCD object.
 We also fetch a pointer to the model that the process uses.  The
 process initializer will create a snapshot of that model.
 
 This procedure
 does not modify the [[local]] stack directly.  The intent(inout) attribute for
 the [[local]] data set is due to the random generator seed which may be
 incremented during initialization.
 
 NOTE: Changes to model parameters within the current context are respected
 only if the process model coincides with the current model.  This is the usual
 case.  If not, we read
 the model from the global model library, which has default parameters.  To
 become more flexible, we should implement a local model library which records
 local changes to currently inactive models.
 <<Integrations: integration: TBP>>=
   procedure :: init_process => integration_init_process
 <<Integrations: procedures>>=
   subroutine integration_init_process (intg, local)
     class(integration_t), intent(inout) :: intg
     type(rt_data_t), intent(inout), target :: local
     type(string_t) :: model_name
     type(model_t), pointer :: model
     class(model_data_t), pointer :: model_instance
     type(var_list_t), pointer :: var_list
     if (debug_on) call msg_debug (D_CORE, "integration_init_process")
     if (.not. local%prclib%contains (intg%process_id)) then
        call msg_fatal ("Process '" // char (intg%process_id) // "' not found" &
             // " in library '" // char (local%prclib%get_name ()) // "'")
        return
     end if
     model_name = local%prclib%get_model_name (intg%process_id)
     if (local%get_sval (var_str ("$model_name")) == model_name) then
        model => local%model
     else
        model => local%model_list%get_model_ptr (model_name)
     end if
     var_list => local%get_var_list_ptr ()
     call intg%process%init (intg%process_id, &
          local%prclib, &
          local%os_data, &
          model, &
          var_list, &
          local%beam_structure)
     intg%run_id = intg%process%get_run_id ()
   end subroutine integration_init_process
 
 @ %def integration_init_process
 @ Initialization, third part: complete process configuration.
 <<Integrations: integration: TBP>>=
   procedure :: setup_process => integration_setup_process
 <<Integrations: procedures>>=
   subroutine integration_setup_process (intg, local, verbose, init_only)
     class(integration_t), intent(inout) :: intg
     type(rt_data_t), intent(inout), target :: local
     logical, intent(in), optional :: verbose
     logical, intent(in), optional :: init_only
 
     type(var_list_t), pointer :: var_list
     class(mci_t), allocatable :: mci_template
     type(sf_config_t), dimension(:), allocatable :: sf_config
     type(sf_prop_t) :: sf_prop
     type(sf_channel_t), dimension(:), allocatable :: sf_channel
     type(phs_channel_collection_t) :: phs_channel_collection
     logical :: sf_trace
     logical :: verb, initialize_only
     type(string_t) :: sf_string
     type(string_t) :: workspace
 
     verb = .true.;  if (present (verbose))  verb = verbose
 
     initialize_only = .false.
     if (present (init_only))  initialize_only = init_only
     
     call display_init_message (verb)
 
     var_list => local%get_var_list_ptr ()
     call setup_log_and_history ()
 
     associate (process => intg%process)
       call set_intg_parameters (process)
 
       call process%setup_cores (dispatch_core, &
            intg%helicity_selection, intg%use_color_factors, intg%has_beam_pol)
 
       call process%init_phs_config ()
       call process%init_components ()
 
       call process%record_inactive_components ()
       intg%process_has_me = process%has_matrix_element ()
       if (.not. intg%process_has_me) then
          call msg_warning ("Process '" &
               // char (intg%process_id) // "': matrix element vanishes")
       end if
 
       call setup_beams ()
       call setup_structure_functions ()
 
       workspace = var_list%get_sval (var_str ("$integrate_workspace"))
       if (workspace == "") then
          call process%configure_phs &
               (intg%rebuild_phs, &
               intg%ignore_phs_mismatch, &
               intg%combined_integration)
       else
          call setup_grid_path (workspace)
          call process%configure_phs &
               (intg%rebuild_phs, &
               intg%ignore_phs_mismatch, &
               intg%combined_integration, &
               workspace)
       end if
 
       call process%complete_pcm_setup ()
 
       call process%prepare_blha_cores ()
       call process%create_blha_interface ()
       call process%prepare_any_external_code ()
 
       call process%setup_terms (with_beams = intg%has_beam_pol)
       call process%check_masses ()
 
       if (verb) then
          call process%write (screen = .true.)
          call process%print_phs_startup_message ()
       end if
 
       if (intg%process_has_me) then
          if (size (sf_config) > 0) then
             call process%collect_channels (phs_channel_collection)
          else if (.not. initialize_only &
               .and. process%contains_trivial_component ()) then
             call msg_fatal ("Integrate: 2 -> 1 process can't be handled &
                  &with fixed-energy beams")
          end if
          call dispatch_sf_channels &
               (sf_channel, sf_string, sf_prop, phs_channel_collection, &
               local%var_list, local%get_sqrts(), local%beam_structure)
          if (allocated (sf_channel)) then
             if (size (sf_channel) > 0) then
                call process%set_sf_channel (sf_channel)
             end if
          end if
          call phs_channel_collection%final ()
          if (verb)  call process%sf_startup_message (sf_string)
       end if
 
       call process%setup_mci (dispatch_mci_s)
 
       call setup_expressions ()
 
       call process%compute_md5sum ()
     end associate
 
   contains
 
     subroutine setup_log_and_history ()
        if (intg%run_id /= "") then
           intg%history_filename = intg%process_id // "." // intg%run_id &
                // ".history"
           intg%log_filename = intg%process_id // "." // intg%run_id // ".log"
        else
           intg%history_filename = intg%process_id // ".history"
           intg%log_filename = intg%process_id // ".log"
        end if
        intg%vis_history = &
           var_list%get_lval (var_str ("?vis_history"))
     end subroutine setup_log_and_history
 
     subroutine set_intg_parameters (process)
       type(process_t), intent(in) :: process
       intg%n_calls_test = &
            var_list%get_ival (var_str ("n_calls_test"))
       intg%combined_integration = &
            var_list%get_lval (var_str ('?combined_nlo_integration')) &
            .and. process%is_nlo_calculation ()
       intg%use_color_factors = &
            var_list%get_lval (var_str ("?read_color_factors"))
       intg%has_beam_pol = &
            local%beam_structure%has_polarized_beams ()
       intg%helicity_selection = &
            local%get_helicity_selection ()
       intg%rebuild_phs = &
            var_list%get_lval (var_str ("?rebuild_phase_space"))
       intg%ignore_phs_mismatch = &
          .not. var_list%get_lval (var_str ("?check_phs_file"))
       intg%phs_only = &
            var_list%get_lval (var_str ("?phs_only"))
     end subroutine set_intg_parameters
 
     subroutine display_init_message (verb)
       logical, intent(in) :: verb
       if (verb) then
          call msg_message ("Initializing integration for process " &
               // char (intg%process_id) // ":")
          if (intg%run_id /= "") &
               call msg_message ("Run ID = " // '"' // char (intg%run_id) // '"')
       end if
     end subroutine display_init_message
 
     subroutine setup_beams ()
       real(default) :: sqrts
       logical :: decay_rest_frame
       sqrts = local%get_sqrts ()
       decay_rest_frame = &
            var_list%get_lval (var_str ("?decay_rest_frame"))
       if (intg%process_has_me) then
          call intg%process%setup_beams_beam_structure &
               (local%beam_structure, sqrts, decay_rest_frame)
       end if
       if (verb .and. intg%process_has_me) then
          call intg%process%beams_startup_message &
               (beam_structure = local%beam_structure)
       end if
     end subroutine setup_beams
 
     subroutine setup_structure_functions ()
       integer :: n_in
       type(pdg_array_t), dimension(:,:), allocatable :: pdg_prc
       type(string_t) :: sf_trace_file
       if (intg%process_has_me) then
          call intg%process%get_pdg_in (pdg_prc)
       else
          n_in = intg%process%get_n_in ()
          allocate (pdg_prc (n_in, intg%process%get_n_components ()))
          pdg_prc = 0
       end if
       call dispatch_sf_config (sf_config, sf_prop, local%beam_structure, &
            local%get_var_list_ptr (), local%var_list, &
            local%model, local%os_data, local%get_sqrts (), pdg_prc)
 
       sf_trace = &
            var_list%get_lval (var_str ("?sf_trace"))
       sf_trace_file = &
            var_list%get_sval (var_str ("$sf_trace_file"))
       if (sf_trace) then
          call intg%process%init_sf_chain (sf_config, sf_trace_file)
       else
          call intg%process%init_sf_chain (sf_config)
       end if
     end subroutine setup_structure_functions
 
     subroutine setup_expressions ()
       type(eval_tree_factory_t) :: expr_factory
       if (associated (local%pn%cuts_lexpr)) then
          if (verb)  call msg_message ("Applying user-defined cuts.")
          call expr_factory%init (local%pn%cuts_lexpr)
          call intg%process%set_cuts (expr_factory)
       else
          if (verb)  call msg_warning ("No cuts have been defined.")
       end if
       if (associated (local%pn%scale_expr)) then
          if (verb) call msg_message ("Using user-defined general scale.")
          call expr_factory%init (local%pn%scale_expr)
          call intg%process%set_scale (expr_factory)
       end if
       if (associated (local%pn%fac_scale_expr)) then
          if (verb) call msg_message ("Using user-defined factorization scale.")
          call expr_factory%init (local%pn%fac_scale_expr)
          call intg%process%set_fac_scale (expr_factory)
       end if
       if (associated (local%pn%ren_scale_expr)) then
          if (verb) call msg_message ("Using user-defined renormalization scale.")
          call expr_factory%init (local%pn%ren_scale_expr)
          call intg%process%set_ren_scale (expr_factory)
       end if
       if (associated (local%pn%weight_expr)) then
          if (verb) call msg_message ("Using user-defined reweighting factor.")
          call expr_factory%init (local%pn%weight_expr)
          call intg%process%set_weight (expr_factory)
       end if
     end subroutine setup_expressions
   end subroutine integration_setup_process
 
 @ %def integration_setup_process
 @
 \subsection{Integration}
 Integrate: do the final integration.  Here, we do a multi-iteration
 integration.  Again, we skip iterations that are already on file.
 Record the results in the global variable list.
 <<Integrations: integration: TBP>>=
   procedure :: evaluate => integration_evaluate
 <<Integrations: procedures>>=
   subroutine integration_evaluate &
        (intg, process_instance, i_mci, pass, it_list, pacify)
     class(integration_t), intent(inout) :: intg
     type(process_instance_t), intent(inout), target :: process_instance
     integer, intent(in) :: i_mci
     integer, intent(in) :: pass
     type(iterations_list_t), intent(in) :: it_list
     logical, intent(in), optional :: pacify
     integer :: n_calls, n_it
     logical :: adapt_grids, adapt_weights, final
     n_it = it_list%get_n_it (pass)
     n_calls = it_list%get_n_calls (pass)
     adapt_grids = it_list%adapt_grids (pass)
     adapt_weights = it_list%adapt_weights (pass)
     final = pass == it_list%get_n_pass ()
     call process_instance%integrate ( &
          i_mci, n_it, n_calls, adapt_grids, adapt_weights, &
          final, pacify)
   end subroutine integration_evaluate
 
 @ %def integration_evaluate
 @ In case the user has not provided a list of iterations, make a
 reasonable default.  This can depend on the process.  The usual
 approach is to define two distinct passes, one for adaptation and one
 for integration.
 <<Integrations: integration: TBP>>=
   procedure :: make_iterations_list => integration_make_iterations_list
 <<Integrations: procedures>>=
   subroutine integration_make_iterations_list (intg, it_list)
     class(integration_t), intent(in) :: intg
     type(iterations_list_t), intent(out) :: it_list
     integer :: pass, n_pass
     integer, dimension(:), allocatable :: n_it, n_calls
     logical, dimension(:), allocatable :: adapt_grids, adapt_weights
     n_pass = intg%process%get_n_pass_default ()
     allocate (n_it (n_pass), n_calls (n_pass))
     allocate (adapt_grids (n_pass), adapt_weights (n_pass))
     do pass = 1, n_pass
        n_it(pass)          = intg%process%get_n_it_default (pass)
        n_calls(pass)       = intg%process%get_n_calls_default (pass)
        adapt_grids(pass)   = intg%process%adapt_grids_default (pass)
        adapt_weights(pass) = intg%process%adapt_weights_default (pass)
     end do
     call it_list%init (n_it, n_calls, &
          adapt_grids = adapt_grids, adapt_weights = adapt_weights)
   end subroutine integration_make_iterations_list
 
 @ %def integration_make_iterations_list
 @ In NLO calculations, the individual components might scale very differently
 with the number of calls. This especially applies to the real-subtracted
 component, which usually fluctuates more than the Born and virtual
 component, making it a bottleneck of the calculation. Thus, the calculation
 is throttled twice, first by the number of calls for the real component,
 second by the number of surplus calls of computation-intense virtual
 matrix elements. Therefore, we want to set a different number of calls
 for each component, which is done by the subroutine [[integration_apply_call_multipliers]].
 <<Integrations: integration: TBP>>=
   procedure :: init_iteration_multipliers => integration_init_iteration_multipliers
 <<Integrations: procedures>>=
   subroutine integration_init_iteration_multipliers (intg, local)
     class(integration_t), intent(inout) :: intg
     type(rt_data_t), intent(in) :: local
     integer :: n_pass, pass
     type(iterations_list_t) :: it_list
     n_pass = local%it_list%get_n_pass ()
     if (n_pass == 0) then
        call intg%make_iterations_list (it_list)
        n_pass = it_list%get_n_pass ()
     end if
     associate (it_multipliers => intg%iteration_multipliers)
        allocate (it_multipliers%n_calls0 (n_pass))
        do pass = 1, n_pass
           it_multipliers%n_calls0(pass) = local%it_list%get_n_calls (pass)
        end do
        it_multipliers%mult_real = local%var_list%get_rval &
            (var_str ("mult_call_real"))
        it_multipliers%mult_virt = local%var_list%get_rval &
            (var_str ("mult_call_virt"))
        it_multipliers%mult_dglap = local%var_list%get_rval &
            (var_str ("mult_call_dglap"))
     end associate
   end subroutine integration_init_iteration_multipliers
 
 @ %def integration_init_iteration_multipliers
 @
 <<Integrations: integration: TBP>>=
   procedure :: apply_call_multipliers => integration_apply_call_multipliers
 <<Integrations: procedures>>=
   subroutine integration_apply_call_multipliers (intg, n_pass, i_component, it_list)
     class(integration_t), intent(in) :: intg
     integer, intent(in) :: n_pass, i_component
     type(iterations_list_t), intent(inout) :: it_list
     integer :: nlo_type
     integer :: n_calls0, n_calls
     integer :: pass
     real(default) :: multiplier
     nlo_type = intg%process%get_component_nlo_type (i_component)
     do pass = 1, n_pass
        associate (multipliers => intg%iteration_multipliers)
          select case (nlo_type)
          case (NLO_REAL)
             multiplier = multipliers%mult_real
          case (NLO_VIRTUAL)
             multiplier = multipliers%mult_virt
          case (NLO_DGLAP)
             multiplier = multipliers%mult_dglap
          case default
             return
          end select
        end associate
        if (n_pass <= size (intg%iteration_multipliers%n_calls0)) then
           n_calls0 = intg%iteration_multipliers%n_calls0 (pass)
           n_calls = floor (multiplier * n_calls0)
           call it_list%set_n_calls (pass, n_calls)
        end if
     end do
   end subroutine integration_apply_call_multipliers
 
 @ %def integration_apply_call_multipliers
 @
 \subsection{API for integration objects}
 This initializer does everything except assigning cuts/scale/weight
 expressions.
 <<Integrations: integration: TBP>>=
   procedure :: init => integration_init
 <<Integrations: procedures>>=
   subroutine integration_init &
        (intg, process_id, local, global, local_stack, init_only)
     class(integration_t), intent(out) :: intg
     type(string_t), intent(in) :: process_id
     type(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(inout), optional, target :: global
     logical, intent(in), optional :: init_only
     logical, intent(in), optional :: local_stack
     logical :: use_local
     use_local = .false.;  if (present (local_stack))  use_local = local_stack
     if (present (global)) then
        call intg%create_process (process_id, global)
     else if (use_local) then
        call intg%create_process (process_id, local)
     else
        call intg%create_process (process_id)
     end if
     call intg%init_process (local)
     call intg%setup_process (local, init_only = init_only)
     call intg%init_iteration_multipliers (local)
   end subroutine integration_init
 
 @ %def integration_init
 @ Do the integration for a single process, both warmup and final evaluation.
 The [[eff_reset]] flag is to suppress numerical noise in the graphical output
 of the integration history.
 <<Integrations: integration: TBP>>=
   procedure :: integrate => integration_integrate
 <<Integrations: procedures>>=
   subroutine integration_integrate (intg, local, eff_reset)
     class(integration_t), intent(inout) :: intg
     type(rt_data_t), intent(in), target :: local
     logical, intent(in), optional :: eff_reset
     type(string_t) :: log_filename
     type(var_list_t), pointer :: var_list
     type(process_instance_t), allocatable, target :: process_instance
     type(iterations_list_t) :: it_list
     logical :: pacify
     integer :: pass, i_mci, n_mci, n_pass
     integer :: i_component
     integer :: nlo_type
     logical :: display_summed
     logical :: nlo_active
     type(string_t) :: component_output
 
     allocate (process_instance)
     call process_instance%init (intg%process)
 
     var_list => intg%process%get_var_list_ptr ()
     call openmp_set_num_threads_verbose &
          (var_list%get_ival (var_str ("openmp_num_threads")), &
           var_list%get_lval (var_str ("?openmp_logging")))
     pacify = var_list%get_lval (var_str ("?pacify"))
 
     display_summed = .true.
     n_mci = intg%process%get_n_mci ()
     if (n_mci == 1) then
        write (msg_buffer, "(A,A,A)") &
             "Starting integration for process '", &
             char (intg%process%get_id ()), "'"
        call msg_message ()
     end if
 
     call setup_hooks ()
 
     nlo_active = any (intg%process%get_component_nlo_type &
          ([(i_mci, i_mci = 1, n_mci)]) /= BORN)
     do i_mci = 1, n_mci
        i_component = intg%process%get_master_component (i_mci)
        nlo_type = intg%process%get_component_nlo_type (i_component)
        if (intg%process%component_can_be_integrated (i_component)) then
           if (n_mci > 1) then
              if (nlo_active) then
                 if (intg%combined_integration .and. nlo_type == BORN) then
                    component_output = var_str ("Combined")
                 else
                    component_output = component_status (nlo_type)
                 end if
                 write (msg_buffer, "(A,A,A,A,A)") &
                      "Starting integration for process '", &
                      char (intg%process%get_id ()), "' part '", &
                      char (component_output), "'"
              else
                 write (msg_buffer, "(A,A,A,I0)") &
                      "Starting integration for process '", &
                      char (intg%process%get_id ()), "' part ", i_mci
              end if
              call msg_message ()
           end if
           n_pass = local%it_list%get_n_pass ()
           if (n_pass == 0) then
              call msg_message ("Integrate: iterations not specified, &
                   &using default")
              call intg%make_iterations_list (it_list)
              n_pass = it_list%get_n_pass ()
           else
              it_list = local%it_list
           end if
           call intg%apply_call_multipliers (n_pass, i_mci, it_list)
           call msg_message ("Integrate: " // char (it_list%to_string ()))
           do pass = 1, n_pass
              call intg%evaluate (process_instance, i_mci, pass, it_list, pacify)
              if (signal_is_pending ())  return
           end do
           call intg%process%final_integration (i_mci)
           if (intg%vis_history) then
              call intg%process%display_integration_history &
                   (i_mci, intg%history_filename, local%os_data, eff_reset)
           end if
           if (local%logfile == intg%log_filename) then
              if (intg%run_id /= "") then
                 log_filename = intg%process_id // "." // intg%run_id // &
                      ".var.log"
              else
                 log_filename = intg%process_id // ".var.log"
              end if
              call msg_message ("Name clash for global logfile and process log: ", &
                   arr =[var_str ("| Renaming log file from ") // local%logfile, &
                         var_str ("|   to ") // log_filename // var_str (" .")])
           else
              log_filename = intg%log_filename
           end if
           call intg%process%write_logfile (i_mci, log_filename)
        end if
     end do
 
     if (n_mci > 1 .and. display_summed) then
        call msg_message ("Integrate: sum of all components")
        call intg%process%display_summed_results (pacify)
     end if
 
     call process_instance%final ()
     deallocate (process_instance)
   contains
     subroutine setup_hooks ()
       class(process_instance_hook_t), pointer :: hook
       call dispatch_evt_shower_hook (hook, var_list, process_instance)
       if (associated (hook)) then
          call process_instance%append_after_hook (hook)
       end if
     end subroutine setup_hooks
   end subroutine integration_integrate
 
 @ %def integration_integrate
 @ Do a dummy integration for a process which could not be initialized (e.g.,
 has no matrix element).  The result is zero.
 <<Integrations: integration: TBP>>=
   procedure :: integrate_dummy => integration_integrate_dummy
 <<Integrations: procedures>>=
   subroutine integration_integrate_dummy (intg)
     class(integration_t), intent(inout) :: intg
     call intg%process%integrate_dummy ()
   end subroutine integration_integrate_dummy
 
 @ %def integration_integrate_dummy
 @ Just sample the matrix element under realistic conditions (but no
 cuts); throw away the results.
 <<Integrations: integration: TBP>>=
   procedure :: sampler_test => integration_sampler_test
 <<Integrations: procedures>>=
   subroutine integration_sampler_test (intg)
     class(integration_t), intent(inout) :: intg
     type(process_instance_t), allocatable, target :: process_instance
     integer :: n_mci, i_mci
     type(timer_t) :: timer_mci, timer_tot
     real(default) :: t_mci, t_tot
     allocate (process_instance)
     call process_instance%init (intg%process)
     n_mci = intg%process%get_n_mci ()
     if (n_mci == 1) then
        write (msg_buffer, "(A,A,A)") &
             "Test: probing process '", &
             char (intg%process%get_id ()), "'"
        call msg_message ()
     end if
     call timer_tot%start ()
     do i_mci = 1, n_mci
        if (n_mci > 1) then
           write (msg_buffer, "(A,A,A,I0)") &
                "Test: probing process '", &
                char (intg%process%get_id ()), "' part ", i_mci
           call msg_message ()
        end if
        call timer_mci%start ()
        call process_instance%sampler_test (i_mci, intg%n_calls_test)
        call timer_mci%stop ()
        t_mci = timer_mci
        write (msg_buffer, "(A,ES12.5)")  "Test: " &
             // "time in seconds (wallclock): ", t_mci
        call msg_message ()
     end do
     call timer_tot%stop ()
     t_tot = timer_tot
     if (n_mci > 1) then
        write (msg_buffer, "(A,ES12.5)")  "Test: " &
             // "total time      (wallclock): ", t_tot
        call msg_message ()
     end if
     call process_instance%final ()
   end subroutine integration_sampler_test
 
 @ %def integration_sampler_test
 @ Return the process pointer (needed by simulate):
 <<Integrations: integration: TBP>>=
   procedure :: get_process_ptr => integration_get_process_ptr
 <<Integrations: procedures>>=
   function integration_get_process_ptr (intg) result (ptr)
     class(integration_t), intent(in) :: intg
     type(process_t), pointer :: ptr
     ptr => intg%process
   end function integration_get_process_ptr
 
 @ %def integration_get_process_ptr
 @ Simply integrate, do a dummy integration if necessary.  The [[integration]]
 object exists only internally.
 
 If the [[global]] environment is provided, the process object is appended to
 the global stack.  Otherwise, if [[local_stack]] is set, we append to the
 local process stack.  If this is unset, the [[process]] object is not recorded
 permanently.
 
 The [[init_only]] flag can be used to skip the actual integration part.  We
 will end up with a process object that is completely initialized, including
 phase space configuration.
 
 The [[eff_reset]] flag is to suppress numerical noise in the visualization
 of the integration history.
 <<Integrations: public>>=
   public :: integrate_process
 <<Integrations: procedures>>=
   subroutine integrate_process (process_id, local, global, local_stack, init_only, eff_reset)
     type(string_t), intent(in) :: process_id
     type(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(inout), optional, target :: global
     logical, intent(in), optional :: local_stack, init_only, eff_reset
     type(string_t) :: prclib_name
     type(integration_t) :: intg
     character(32) :: buffer
   <<Integrations: integrate process: variables>>
   <<Integrations: integrate process: init>>
     if (.not. associated (local%prclib)) then
        call msg_fatal ("Integrate: current process library is undefined")
        return
     end if
 
     if (.not. local%prclib%is_active ()) then
        call msg_message ("Integrate: current process library needs compilation")
        prclib_name = local%prclib%get_name ()
        call compile_library (prclib_name, local)
        if (signal_is_pending ())  return
        call msg_message ("Integrate: compilation done")
     end if
 
     call intg%init (process_id, local, global, local_stack, init_only)
     if (signal_is_pending ())  return
 
     if (present (init_only)) then
        if (init_only) return
     end if
 
     if (intg%n_calls_test > 0) then
        write (buffer, "(I0)")  intg%n_calls_test
        call msg_message ("Integrate: test (" // trim (buffer) // " calls) ...")
        call intg%sampler_test ()
        call msg_message ("Integrate: ... test complete.")
        if (signal_is_pending ())  return
     end if
   <<Integrations: integrate process: end init>>
 
     if (intg%phs_only) then
        call msg_message ("Integrate: phase space only, skipping integration")
     else
        if (intg%process_has_me) then
           call intg%integrate (local, eff_reset)
        else
           call intg%integrate_dummy ()
        end if
     end if
   end subroutine integrate_process
 
 @ %def integrate_process
 <<Integrations: integrate process: variables>>=
 @
 <<Integrations: integrate process: init>>=
 @
 <<Integrations: integrate process: end init>>=
 @
 @ The parallelization leads to undefined behavior while writing simultaneously to one file.
 The master worker has to initialize single-handed the corresponding library files and the phase space file.
 The slave worker will wait with a blocking [[MPI_BCAST]] until they receive a logical flag.
 <<MPI: Integrations: integrate process: variables>>=
   type(var_list_t), pointer :: var_list
   logical :: mpi_logging, process_init
   integer :: rank, n_size
 <<MPI: Integrations: integrate process: init>>=
   if (debug_on) call msg_debug (D_MPI, "integrate_process")
   var_list => local%get_var_list_ptr ()
   process_init = .false.
   call mpi_get_comm_id (n_size, rank)
   mpi_logging = (("vamp2" == char (var_list%get_sval (var_str ("$integration_method"))) .and. &
        & (n_size > 1)) .or. var_list%get_lval (var_str ("?mpi_logging")))
   if (debug_on) call msg_debug (D_MPI, "n_size", rank)
   if (debug_on) call msg_debug (D_MPI, "rank", rank)
   if (debug_on) call msg_debug (D_MPI, "mpi_logging", mpi_logging)
   if (rank /= 0) then
      if (mpi_logging) then
         call msg_message ("MPI: wait for master to finish process initialization ...")
      end if
      call MPI_bcast (process_init, 1, MPI_LOGICAL, 0, MPI_COMM_WORLD)
   else
      process_init = .true.
   end if
 
   if (process_init) then
 <<MPI: Integrations: integrate process: end init>>=
   if (rank == 0) then
      if (mpi_logging) then
         call msg_message ("MPI: finish process initialization, load slaves ...")
      end if
      call MPI_bcast (process_init, 1, MPI_LOGICAL, 0, MPI_COMM_WORLD)
   end if
 end if
 call MPI_barrier (MPI_COMM_WORLD)
 call mpi_set_logging (mpi_logging)
 @ %def integrate_process_mpi
 @
 \subsection{Unit Tests}
 Test module, followed by the stand-alone unit-test procedures.
 <<[[integrations_ut.f90]]>>=
 <<File header>>
 
 module integrations_ut
   use unit_tests
   use integrations_uti
 
 <<Standard module head>>
 
 <<Integrations: public test>>
 
 contains
 
 <<Integrations: test driver>>
 
 end module integrations_ut
 @ %def integrations_ut
 @
 <<[[integrations_uti.f90]]>>=
 <<File header>>
 
 module integrations_uti
 
 <<Use kinds>>
 <<Use strings>>
   use io_units
   use ifiles
   use lexers
   use parser
   use io_units
   use flavors
   use interactions, only: reset_interaction_counter
   use phs_forests
   use eval_trees
   use models
   use rt_data
   use process_configurations_ut, only: prepare_test_library
   use compilations, only: compile_library
 
   use integrations
 
   use phs_wood_ut, only: write_test_phs_file
 
 <<Standard module head>>
 
 <<Integrations: test declarations>>
 
 contains
 
 <<Integrations: tests>>
 
 end module integrations_uti
 
 @ %def integrations_uti
 @ API: driver for the unit tests below.
 <<Integrations: public test>>=
   public :: integrations_test
 <<Integrations: test driver>>=
   subroutine integrations_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Integrations: execute tests>>
   end subroutine integrations_test
 
 @ %def integrations_test
 @
 <<Integrations: public test>>=
   public :: integrations_history_test
 <<Integrations: test driver>>=
   subroutine integrations_history_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Integrations: execute history tests>>
   end subroutine integrations_history_test
 
 @ %def integrations_history_test
 @
 \subsubsection{Integration of test process}
 Compile and integrate an intrinsic test matrix element ([[prc_test]]
 type).  The phase-space implementation is [[phs_single]]
 (single-particle phase space), the integrator is [[mci_midpoint]].
 
 The cross section for the $2\to 2$ process $ss\to ss$ with its
 constant matrix element is given by
 \begin{equation}
   \sigma = c\times f\times \Phi_2 \times |M|^2.
 \end{equation}
 $c$ is the conversion constant
 \begin{equation}
   c = 0.3894\times 10^{12}\;\mathrm{fb}\,\mathrm{GeV}^2.
 \end{equation}
 $f$ is the flux of the incoming particles with mass
 $m=125\,\mathrm{GeV}$ and energy $\sqrt{s}=1000\,\mathrm{GeV}$
 \begin{equation}
   f = \frac{(2\pi)^4}{2\lambda^{1/2}(s,m^2,m^2)}
     = \frac{(2\pi)^4}{2\sqrt{s}\,\sqrt{s - 4m^2}}
     = 8.048\times 10^{-4}\;\mathrm{GeV}^{-2}
 \end{equation}
 $\Phi_2$ is the volume of the two-particle phase space
 \begin{equation}
   \Phi_2 = \frac{1}{4(2\pi)^5} = 2.5529\times 10^{-5}.
 \end{equation}
 The squared matrix element $|M|^2$ is unity.
 Combining everything, we obtain
 \begin{equation}
   \sigma = 8000\;\mathrm{fb}
 \end{equation}
 This number should appear as the final result.
 
 Note: In this and the following test, we reset the Fortran compiler and flag
 variables immediately before they are printed, so the test is portable.
 <<Integrations: execute tests>>=
   call test (integrations_1, "integrations_1", &
        "intrinsic test process", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_1
 <<Integrations: tests>>=
   subroutine integrations_1 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: integrations_1"
     write (u, "(A)")  "*   Purpose: integrate test process"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
 
     libname = "integration_1"
     procname = "prc_config_a"
 
     call prepare_test_library (global, libname, 1)
     call compile_library (libname, global)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("integrations1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     call reset_interaction_counter ()
     call integrate_process (procname, global, local_stack=.true.)
 
     call global%write (u, vars = [ &
          var_str ("$method"), &
          var_str ("sqrts"), &
          var_str ("$integration_method"), &
          var_str ("$phs_method"), &
          var_str ("$run_id")])
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_1"
 
   end subroutine integrations_1
 
 @ %def integrations_1
 @
 \subsubsection{Integration with cuts}
 Compile and integrate an intrinsic test matrix element ([[prc_test]]
 type) with cuts set.
 <<Integrations: execute tests>>=
   call test (integrations_2, "integrations_2", &
        "intrinsic test process with cut", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_2
 <<Integrations: tests>>=
   subroutine integrations_2 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
 
     type(string_t) :: cut_expr_text
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: parse_tree
 
     type(string_t), dimension(0) :: empty_string_array
 
     write (u, "(A)")  "* Test output: integrations_2"
     write (u, "(A)")  "*   Purpose: integrate test process with cut"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
 
     write (u, "(A)")  "* Prepare a cut expression"
     write (u, "(A)")
 
     call syntax_pexpr_init ()
     cut_expr_text = "all Pt > 100 [s]"
     call ifile_append (ifile, cut_expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_lexpr (parse_tree, stream, .true.)
     global%pn%cuts_lexpr => parse_tree%get_root_ptr ()
 
     write (u, "(A)")  "* Build and initialize a test process"
     write (u, "(A)")
 
     libname = "integration_3"
     procname = "prc_config_a"
 
     call prepare_test_library (global, libname, 1)
     call compile_library (libname, global)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("integrations1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     call reset_interaction_counter ()
     call integrate_process (procname, global, local_stack=.true.)
 
     call global%write (u, vars = empty_string_array)
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_2"
 
   end subroutine integrations_2
 
 @ %def integrations_2
 @
 \subsubsection{Standard phase space}
 Compile and integrate an intrinsic test matrix element ([[prc_test]]
 type) using the default ([[phs_wood]]) phase-space implementation.  We
 use an explicit phase-space configuration file with a single channel
 and integrate by [[mci_midpoint]].
 <<Integrations: execute tests>>=
   call test (integrations_3, "integrations_3", &
        "standard phase space", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_3
 <<Integrations: tests>>=
   subroutine integrations_3 (u)
   <<Use kinds>>
   <<Use strings>>
     use interactions, only: reset_interaction_counter
     use models
     use rt_data
     use process_configurations_ut, only: prepare_test_library
     use compilations, only: compile_library
     use integrations
 
     implicit none
 
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
     integer :: u_phs
 
     write (u, "(A)")  "* Test output: integrations_3"
     write (u, "(A)")  "*   Purpose: integrate test process"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and parameters"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     call global%global_init ()
 
     libname = "integration_3"
     procname = "prc_config_a"
 
     call prepare_test_library (global, libname, 1)
     call compile_library (libname, global)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("integrations1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("default"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?phs_s_mapping"),&
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     write (u, "(A)")  "* Create a scratch phase-space file"
     write (u, "(A)")
 
     u_phs = free_unit ()
     open (u_phs, file = "integrations_3.phs", &
          status = "replace", action = "write")
     call write_test_phs_file (u_phs, var_str ("prc_config_a_i1"))
     close (u_phs)
 
     call global%set_string (var_str ("$phs_file"),&
          var_str ("integrations_3.phs"), is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     write (u, "(A)")  "* Integrate"
     write (u, "(A)")
 
     call reset_interaction_counter ()
     call integrate_process (procname, global, local_stack=.true.)
 
     call global%write (u, vars = [ &
          var_str ("$phs_method"), &
          var_str ("$phs_file")])
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_phs_forest_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_3"
 
   end subroutine integrations_3
 
 @ %def integrations_3
 @
 \subsubsection{VAMP integration}
 Compile and integrate an intrinsic test matrix element ([[prc_test]]
 type) using the single-channel ([[phs_single]]) phase-space
 implementation.  The integration method is [[vamp]].
 <<Integrations: execute tests>>=
   call test (integrations_4, "integrations_4", &
        "VAMP integration (one iteration)", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_4
 <<Integrations: tests>>=
   subroutine integrations_4 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: integrations_4"
     write (u, "(A)")  "*   Purpose: integrate test process using VAMP"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and parameters"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
 
     libname = "integrations_4_lib"
     procname = "integrations_4"
 
     call prepare_test_library (global, libname, 1, [procname])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     write (u, "(A)")  "* Integrate"
     write (u, "(A)")
 
     call reset_interaction_counter ()
     call integrate_process (procname, global, local_stack=.true.)
 
     call global%pacify (efficiency_reset = .true., error_reset = .true.)
     call global%write (u, vars = [var_str ("$integration_method")], &
             pacify = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_4"
 
   end subroutine integrations_4
 
 @ %def integrations_4
 @
 \subsubsection{Multiple iterations integration}
 Compile and integrate an intrinsic test matrix element ([[prc_test]]
 type) using the single-channel ([[phs_single]]) phase-space
 implementation.  The integration method is [[vamp]].  We launch three
 iterations.
 <<Integrations: execute tests>>=
   call test (integrations_5, "integrations_5", &
        "VAMP integration (three iterations)", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_5
 <<Integrations: tests>>=
   subroutine integrations_5 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
 
     write (u, "(A)")  "* Test output: integrations_5"
     write (u, "(A)")  "*   Purpose: integrate test process using VAMP"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and parameters"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
 
     libname = "integrations_5_lib"
     procname = "integrations_5"
 
     call prepare_test_library (global, libname, 1, [procname])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([3], [1000])
 
     write (u, "(A)")  "* Integrate"
     write (u, "(A)")
 
     call reset_interaction_counter ()
     call integrate_process (procname, global, local_stack=.true.)
 
     call global%pacify (efficiency_reset = .true., error_reset = .true.)
     call global%write (u, vars = [var_str ("$integration_method")], &
             pacify = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_5"
 
   end subroutine integrations_5
 
 @ %def integrations_5
 @
 \subsubsection{Multiple passes integration}
 Compile and integrate an intrinsic test matrix element ([[prc_test]]
 type) using the single-channel ([[phs_single]]) phase-space
 implementation.  The integration method is [[vamp]].  We launch three
 passes with three iterations each.
 <<Integrations: execute tests>>=
   call test (integrations_6, "integrations_6", &
        "VAMP integration (three passes)", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_6
 <<Integrations: tests>>=
   subroutine integrations_6 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
     type(string_t), dimension(0) :: no_vars
 
     write (u, "(A)")  "* Test output: integrations_6"
     write (u, "(A)")  "*   Purpose: integrate test process using VAMP"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and parameters"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
 
     libname = "integrations_6_lib"
     procname = "integrations_6"
 
     call prepare_test_library (global, libname, 1, [procname])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([3, 3, 3], [1000, 1000, 1000], &
          adapt = [.true., .true., .false.], &
          adapt_code = [var_str ("wg"), var_str ("g"), var_str ("")])
 
     write (u, "(A)")  "* Integrate"
     write (u, "(A)")
 
     call reset_interaction_counter ()
     call integrate_process (procname, global, local_stack=.true.)
 
     call global%pacify (efficiency_reset = .true., error_reset = .true.)
     call global%write (u, vars = no_vars, pacify = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_6"
 
   end subroutine integrations_6
 
 @ %def integrations_6
 @
 \subsubsection{VAMP and default phase space}
 Compile and integrate an intrinsic test matrix element ([[prc_test]]
 type) using the default ([[phs_wood]]) phase-space
 implementation.  The integration method is [[vamp]].  We launch three
 passes with three iterations each.  We enable channel equivalences and
 groves.
 <<Integrations: execute tests>>=
   call test (integrations_7, "integrations_7", &
        "VAMP integration with wood phase space", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_7
 <<Integrations: tests>>=
   subroutine integrations_7 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
     type(string_t), dimension(0) :: no_vars
     integer :: iostat, u_phs
     character(95) :: buffer
     type(string_t) :: phs_file
     logical :: exist
 
     write (u, "(A)")  "* Test output: integrations_7"
     write (u, "(A)")  "*   Purpose: integrate test process using VAMP"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and parameters"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     call global%global_init ()
 
     libname = "integrations_7_lib"
     procname = "integrations_7"
 
     call prepare_test_library (global, libname, 1, [procname])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("wood"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .true., is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?phs_s_mapping"),&
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([3, 3, 3], [1000, 1000, 1000], &
          adapt = [.true., .true., .false.], &
          adapt_code = [var_str ("wg"), var_str ("g"), var_str ("")])
 
     write (u, "(A)")  "* Integrate"
     write (u, "(A)")
 
     call reset_interaction_counter ()
     call integrate_process (procname, global, local_stack=.true.)
 
     call global%pacify (efficiency_reset = .true., error_reset = .true.)
     call global%write (u, vars = no_vars, pacify = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_phs_forest_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Generated phase-space file"
     write (u, "(A)")
 
     phs_file = procname // ".r1.i1.phs"
     inquire (file = char (phs_file), exist = exist)
     if (exist) then
        u_phs = free_unit ()
        open (u_phs, file = char (phs_file), action = "read", status = "old")
        iostat = 0
        do while (iostat == 0)
           read (u_phs, "(A)", iostat = iostat)  buffer
           if (iostat == 0)  write (u, "(A)")  trim (buffer)
        end do
        close (u_phs)
     else
        write (u, "(A)")  "[file is missing]"
     end if
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_7"
 
   end subroutine integrations_7
 
 @ %def integrations_7
 @
 \subsubsection{Structure functions}
 Compile and integrate an intrinsic test matrix element ([[prc_test]]
 type) using the default ([[phs_wood]]) phase-space
 implementation.  The integration method is [[vamp]].  There is a structure
 function of type [[unit_test]].
 
 We use a test structure function $f(x)=x$ for both beams.  Together with the
 $1/x_1x_2$ factor from the phase-space flux and a unit matrix element, we
 should get the same result as previously for the process without structure
 functions.  There is a slight correction due to the $m_s$ mass which we set to
 zero here.
 <<Integrations: execute tests>>=
   call test (integrations_8, "integrations_8", &
        "integration with structure function", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_8
 <<Integrations: tests>>=
   subroutine integrations_8 (u)
   <<Use kinds>>
   <<Use strings>>
     use interactions, only: reset_interaction_counter
     use phs_forests
     use models
     use rt_data
     use process_configurations_ut, only: prepare_test_library
     use compilations, only: compile_library
     use integrations
 
     implicit none
 
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
     type(flavor_t) :: flv
     type(string_t) :: name
 
     write (u, "(A)")  "* Test output: integrations_8"
     write (u, "(A)")  "*   Purpose: integrate test process using VAMP &
          &with structure function"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and parameters"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     call global%global_init ()
 
     libname = "integrations_8_lib"
     procname = "integrations_8"
 
     call prepare_test_library (global, libname, 1, [procname])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("wood"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .true., is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?phs_s_mapping"),&
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%model_set_real (var_str ("ms"), 0._default)
 
     call reset_interaction_counter ()
 
     call flv%init (25, global%model)
 
     name = flv%get_name ()
     call global%beam_structure%init_sf ([name, name], [1])
     call global%beam_structure%set_sf (1, 1, var_str ("sf_test_1"))
 
     write (u, "(A)")  "* Integrate"
     write (u, "(A)")
 
     call global%it_list%init ([1], [1000])
     call integrate_process (procname, global, local_stack=.true.)
 
     call global%write (u, vars = [var_str ("ms")])
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_phs_forest_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_8"
 
   end subroutine integrations_8
 
 @ %def integrations_8
 @
 \subsubsection{Integration with sign change}
 Compile and integrate an intrinsic test matrix element ([[prc_test]]
 type).  The phase-space implementation is [[phs_single]]
 (single-particle phase space), the integrator is [[mci_midpoint]].
 The weight that is applied changes the sign in half of phase space.
 The weight is $-3$ and $1$, respectively, so the total result is equal
 to the original, but negative sign.
 
 The efficiency should (approximately) become the average of $1$ and
 $1/3$, that is $2/3$.
 <<Integrations: execute tests>>=
   call test (integrations_9, "integrations_9", &
        "handle sign change", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_9
 <<Integrations: tests>>=
   subroutine integrations_9 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
 
     type(string_t) :: wgt_expr_text
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: parse_tree
 
     write (u, "(A)")  "* Test output: integrations_9"
     write (u, "(A)")  "*   Purpose: integrate test process"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
 
     write (u, "(A)")  "* Prepare a weight expression"
     write (u, "(A)")
 
     call syntax_pexpr_init ()
     wgt_expr_text = "eval 2 * sgn (Pz) - 1 [s]"
     call ifile_append (ifile, wgt_expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (parse_tree, stream, .true.)
     global%pn%weight_expr => parse_tree%get_root_ptr ()
 
     write (u, "(A)")  "* Build and evaluate a test process"
     write (u, "(A)")
 
     libname = "integration_9"
     procname = "prc_config_a"
 
     call prepare_test_library (global, libname, 1)
     call compile_library (libname, global)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("integrations1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     call reset_interaction_counter ()
     call integrate_process (procname, global, local_stack=.true.)
 
     call global%write (u, vars = [ &
          var_str ("$method"), &
          var_str ("sqrts"), &
          var_str ("$integration_method"), &
          var_str ("$phs_method"), &
          var_str ("$run_id")])
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_9"
 
   end subroutine integrations_9
 
 @ %def integrations_9
 @
 \subsubsection{Integration history for VAMP integration with default
   phase space}
 This test is only run when event analysis can be done.
 <<Integrations: execute history tests>>=
   call test (integrations_history_1, "integrations_history_1", &
        "Test integration history files", &
        u, results)
 <<Integrations: test declarations>>=
   public :: integrations_history_1
 <<Integrations: tests>>=
   subroutine integrations_history_1 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname
     type(rt_data_t), target :: global
     type(string_t), dimension(0) :: no_vars
     integer :: iostat, u_his
     character(91) :: buffer
     type(string_t) :: his_file, ps_file, pdf_file
     logical :: exist, exist_ps, exist_pdf
 
     write (u, "(A)")  "* Test output: integrations_history_1"
     write (u, "(A)")  "*   Purpose: test integration history files"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and parameters"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     call global%global_init ()
 
     libname = "integrations_history_1_lib"
     procname = "integrations_history_1"
 
     call global%set_log (var_str ("?vis_history"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?phs_s_mapping"),&
          .false., is_known = .true.)
 
     call prepare_test_library (global, libname, 1, [procname])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("wood"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .true., is_known = .true.)
     call global%set_real (var_str ("error_threshold"),&
          5E-6_default, is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known=.true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([2, 2, 2], [1000, 1000, 1000], &
          adapt = [.true., .true., .false.], &
          adapt_code = [var_str ("wg"), var_str ("g"), var_str ("")])
 
     write (u, "(A)")  "* Integrate"
     write (u, "(A)")
 
     call reset_interaction_counter ()
     call integrate_process (procname, global, local_stack=.true., &
          eff_reset = .true.)
 
     call global%pacify (efficiency_reset = .true., error_reset = .true.)
     call global%write (u, vars = no_vars, pacify = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Generated history files"
     write (u, "(A)")
 
     his_file = procname // ".r1.history.tex"
     ps_file  = procname // ".r1.history.ps"
     pdf_file = procname // ".r1.history.pdf"
     inquire (file = char (his_file), exist = exist)
     if (exist) then
        u_his = free_unit ()
        open (u_his, file = char (his_file), action = "read", status = "old")
        iostat = 0
        do while (iostat == 0)
           read (u_his, "(A)", iostat = iostat)  buffer
           if (iostat == 0)  write (u, "(A)")  trim (buffer)
        end do
        close (u_his)
     else
        write (u, "(A)")  "[History LaTeX file is missing]"
     end if
     inquire (file = char (ps_file), exist = exist_ps)
     if (exist_ps) then
        write (u, "(A)")  "[History Postscript file exists and is nonempty]"
     else
        write (u, "(A)")  "[History Postscript file is missing/non-regular]"
     end if
     inquire (file = char (pdf_file), exist = exist_pdf)
     if (exist_pdf) then
        write (u, "(A)")  "[History PDF file exists and is nonempty]"
     else
        write (u, "(A)")  "[History PDF file is missing/non-regular]"
     end if
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_phs_forest_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: integrations_history_1"
 
   end subroutine integrations_history_1
 
 @ %def integrations_history_1
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Event Streams}
 This module manages I/O from/to multiple concurrent event streams.
 Usually, there is at most one input stream, but several output
 streams.  For the latter, we set up an array which can hold [[eio_t]]
 (event I/O) objects of different dynamic types simultaneously.  One of
 them may be marked as an input channel.
 <<[[event_streams.f90]]>>=
 <<File header>>
 
 module event_streams
 
 <<Use strings>>
   use io_units
   use diagnostics
   use events
   use eio_data
   use eio_base
   use rt_data
 
   use dispatch_transforms, only: dispatch_eio
 
 <<Standard module head>>
 
 <<Event streams: public>>
 
 <<Event streams: types>>
 
 contains
 
 <<Event streams: procedures>>
 
 end module event_streams
 @ %def event_streams
 @
 \subsection{Event Stream Array}
 Each entry is an [[eio_t]] object.  Since the type is dynamic, we need
 a wrapper:
 <<Event streams: types>>=
   type :: event_stream_entry_t
      class(eio_t), allocatable :: eio
   end type event_stream_entry_t
 
 @ %def event_stream_entry_t
 @ An array of event-stream entry objects.  If one of the entries is an
 input channel, [[i_in]] is the corresponding index.
 <<Event streams: public>>=
   public :: event_stream_array_t
 <<Event streams: types>>=
   type :: event_stream_array_t
      type(event_stream_entry_t), dimension(:), allocatable :: entry
      integer :: i_in = 0
    contains
    <<Event streams: event stream array: TBP>>
   end type event_stream_array_t
 
 @ %def event_stream_array_t
 @ Output.
 <<Event streams: event stream array: TBP>>=
   procedure :: write => event_stream_array_write
 <<Event streams: procedures>>=
   subroutine event_stream_array_write (object, unit)
     class(event_stream_array_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer :: u, i
     u = given_output_unit (unit)
     write (u, "(1x,A)")  "Event stream array:"
     if (allocated (object%entry)) then
        select case (size (object%entry))
        case (0)
           write (u, "(3x,A)")  "[empty]"
        case default
           do i = 1, size (object%entry)
              if (i == object%i_in)  write (u, "(1x,A)")  "Input stream:"
              call object%entry(i)%eio%write (u)
           end do
        end select
     else
        write (u, "(3x,A)")  "[undefined]"
     end if
   end subroutine event_stream_array_write
 
 @ %def event_stream_array_write
 @ Finalize all streams.
 <<Event streams: event stream array: TBP>>=
   procedure :: final => event_stream_array_final
 <<Event streams: procedures>>=
   subroutine event_stream_array_final (es_array)
     class(event_stream_array_t), intent(inout) :: es_array
     integer :: i
     do i = 1, size (es_array%entry)
        call es_array%entry(i)%eio%final ()
     end do
   end subroutine event_stream_array_final
 
 @ %def event_stream_array_final
 @ Initialization.  We use a generic [[sample]] name, open event I/O
 objects for all provided stream types (using the [[dispatch_eio]]
 routine), and initialize for the given list of process pointers.  If
 there is an [[input]] argument, this channel is initialized as an input
 channel and appended to the array.
 
 The [[input_data]] or, if not present, [[data]] may be modified.  This
 happens if we open a stream for reading and get new information there.
 <<Event streams: event stream array: TBP>>=
   procedure :: init => event_stream_array_init
 <<Event streams: procedures>>=
   subroutine event_stream_array_init &
        (es_array, sample, stream_fmt, global, &
        data, input, input_sample, input_data, allow_switch, &
        checkpoint, callback, &
        error)
     class(event_stream_array_t), intent(out) :: es_array
     type(string_t), intent(in) :: sample
     type(string_t), dimension(:), intent(in) :: stream_fmt
     type(rt_data_t), intent(in) :: global
     type(event_sample_data_t), intent(inout), optional :: data
     type(string_t), intent(in), optional :: input
     type(string_t), intent(in), optional :: input_sample
     type(event_sample_data_t), intent(inout), optional :: input_data
     logical, intent(in), optional :: allow_switch
     integer, intent(in), optional :: checkpoint
     integer, intent(in), optional :: callback
     logical, intent(out), optional :: error
     type(string_t) :: sample_in
     integer :: n, i, n_output, i_input, i_checkpoint, i_callback
     logical :: success, switch
     if (present (input_sample)) then
        sample_in = input_sample
     else
        sample_in = sample
     end if
     if (present (allow_switch)) then
        switch = allow_switch
     else
        switch = .true.
     end if
     if (present (error)) then
        error = .false.
     end if
     n = size (stream_fmt)
     n_output = n
     if (present (input)) then
        n = n + 1
        i_input = n
     else
        i_input = 0
     end if
     if (present (checkpoint)) then
        n = n + 1
        i_checkpoint = n
     else
        i_checkpoint = 0
     end if
     if (present (callback)) then
        n = n + 1
        i_callback = n
     else
        i_callback = 0
     end if
     allocate (es_array%entry (n))
     if (i_checkpoint > 0) then
        call dispatch_eio &
             (es_array%entry(i_checkpoint)%eio, var_str ("checkpoint"), &
             global%var_list, global%fallback_model, &
             global%event_callback)
        call es_array%entry(i_checkpoint)%eio%init_out (sample, data)
     end if
     if (i_callback > 0) then
        call dispatch_eio &
             (es_array%entry(i_callback)%eio, var_str ("callback"), &
             global%var_list, global%fallback_model, &
             global%event_callback)
        call es_array%entry(i_callback)%eio%init_out (sample, data)
     end if
     if (i_input > 0) then
        call dispatch_eio (es_array%entry(i_input)%eio, input, &
             global%var_list, global%fallback_model, &
             global%event_callback)
        if (present (input_data)) then
           call es_array%entry(i_input)%eio%init_in &
                (sample_in, input_data, success)
        else
           call es_array%entry(i_input)%eio%init_in &
                (sample_in, data, success)
        end if
        if (success) then
           es_array%i_in = i_input
        else if (present (input_sample)) then
           if (present (error)) then
              error = .true.
           else
              call msg_fatal ("Events: &
                   &parameter mismatch in input, aborting")
           end if
        else
           call msg_message ("Events: &
                &parameter mismatch, discarding old event set")
           call es_array%entry(i_input)%eio%final ()
           if (switch) then
              call msg_message ("Events: generating new events")
              call es_array%entry(i_input)%eio%init_out (sample, data)
           end if
        end if
     end if
     do i = 1, n_output
        call dispatch_eio (es_array%entry(i)%eio, stream_fmt(i), &
             global%var_list, global%fallback_model, &
             global%event_callback)
        call es_array%entry(i)%eio%init_out (sample, data)
     end do
   end subroutine event_stream_array_init
 
 @ %def event_stream_array_init
 @ Switch the (only) input channel to an output channel, so further
 events are appended to the respective stream.
 <<Event streams: event stream array: TBP>>=
   procedure :: switch_inout => event_stream_array_switch_inout
 <<Event streams: procedures>>=
   subroutine event_stream_array_switch_inout (es_array)
     class(event_stream_array_t), intent(inout) :: es_array
     integer :: n
     if (es_array%has_input ()) then
        n = es_array%i_in
        call es_array%entry(n)%eio%switch_inout ()
        es_array%i_in = 0
     else
        call msg_bug ("Reading events: switch_inout: no input stream selected")
     end if
   end subroutine event_stream_array_switch_inout
 
 @ %def event_stream_array_switch_inout
 @ Output an event (with given process number) to all output streams.
 If there is no output stream, do nothing.
 <<Event streams: event stream array: TBP>>=
   procedure :: output => event_stream_array_output
 <<Event streams: procedures>>=
   subroutine event_stream_array_output (es_array, event, i_prc, &
                                         event_index, passed, pacify)
     class(event_stream_array_t), intent(inout) :: es_array
     type(event_t), intent(in), target :: event
     integer, intent(in) :: i_prc, event_index
     logical, intent(in), optional :: passed, pacify
     logical :: increased
     integer :: i
     do i = 1, size (es_array%entry)
        if (i /= es_array%i_in) then
           associate (eio => es_array%entry(i)%eio)
             if (eio%split) then
                if (eio%split_n_evt > 0 .and. event_index > 1) then
                   if (mod (event_index, eio%split_n_evt) == 1) then
                      call eio%split_out ()
                   end if
                else if (eio%split_n_kbytes > 0) then
                   call eio%update_split_count (increased)
                   if (increased)  call eio%split_out ()
                end if
             end if
             call eio%output (event, i_prc, reading = es_array%i_in /= 0, &
                  passed = passed, &
                  pacify = pacify)
           end associate
        end if
     end do
   end subroutine event_stream_array_output
 
 @ %def event_stream_array_output
 @ Input the [[i_prc]] index which selects the process for the current
 event.  This is separated from reading the event, because it
 determines which event record to read.  [[iostat]] may indicate an
 error or an EOF condition, as usual.
 <<Event streams: event stream array: TBP>>=
   procedure :: input_i_prc => event_stream_array_input_i_prc
 <<Event streams: procedures>>=
   subroutine event_stream_array_input_i_prc (es_array, i_prc, iostat)
     class(event_stream_array_t), intent(inout) :: es_array
     integer, intent(out) :: i_prc
     integer, intent(out) :: iostat
     integer :: n
     if (es_array%has_input ()) then
        n = es_array%i_in
        call es_array%entry(n)%eio%input_i_prc (i_prc, iostat)
     else
        call msg_fatal ("Reading events: no input stream selected")
     end if
   end subroutine event_stream_array_input_i_prc
 
 @ %def event_stream_array_input_i_prc
 @ Input an event from the selected input stream.  [[iostat]] may indicate an
 error or an EOF condition, as usual.
 <<Event streams: event stream array: TBP>>=
   procedure :: input_event => event_stream_array_input_event
 <<Event streams: procedures>>=
   subroutine event_stream_array_input_event (es_array, event, iostat)
     class(event_stream_array_t), intent(inout) :: es_array
     type(event_t), intent(inout), target :: event
     integer, intent(out) :: iostat
     integer :: n
     if (es_array%has_input ()) then
        n = es_array%i_in
        call es_array%entry(n)%eio%input_event (event, iostat)
     else
        call msg_fatal ("Reading events: no input stream selected")
     end if
   end subroutine event_stream_array_input_event
 
 @ %def event_stream_array_input_event
 @ Skip an entry of eio\_t. Used to synchronize the event read-in for
 NLO events.
 <<Event streams: event stream array: TBP>>=
   procedure :: skip_eio_entry => event_stream_array_skip_eio_entry
 <<Event streams: procedures>>=
   subroutine event_stream_array_skip_eio_entry (es_array, iostat)
     class(event_stream_array_t), intent(inout) :: es_array
     integer, intent(out) :: iostat
     integer :: n
     if (es_array%has_input ()) then
        n = es_array%i_in
        call es_array%entry(n)%eio%skip (iostat)
     else
        call msg_fatal ("Reading events: no input stream selected")
     end if
   end subroutine event_stream_array_skip_eio_entry
 
 @ %def event_stream_array_skip_eio_entry
 @ Return true if there is an input channel among the event streams.
 <<Event streams: event stream array: TBP>>=
   procedure :: has_input => event_stream_array_has_input
 <<Event streams: procedures>>=
   function event_stream_array_has_input (es_array) result (flag)
     class(event_stream_array_t), intent(in) :: es_array
     logical :: flag
     flag = es_array%i_in /= 0
   end function event_stream_array_has_input
 
 @ %def event_stream_array_has_input
 @
 \subsection{Unit Tests}
 Test module, followed by the stand-alone unit-test procedures.
 <<[[event_streams_ut.f90]]>>=
 <<File header>>
 
 module event_streams_ut
   use unit_tests
   use event_streams_uti
 
 <<Standard module head>>
 
 <<Event streams: public test>>
 
 contains
 
 <<Event streams: test driver>>
 
 end module event_streams_ut
 @
 <<[[event_streams_uti.f90]]>>=
 <<File header>>
 
 module event_streams_uti
 
 <<Use kinds>>
 <<Use strings>>
   use model_data
   use eio_data
   use process, only: process_t
   use instances, only: process_instance_t
   use models
   use rt_data
   use events
 
   use event_streams
 
 <<Standard module head>>
 
 <<Event streams: test declarations>>
 
 contains
 
 <<Event streams: tests>>
 
 end module event_streams_uti
 
 @ %def event_streams_uti
 @ API: driver for the unit tests below.
 <<Event streams: public test>>=
   public :: event_streams_test
 <<Event streams: test driver>>=
   subroutine event_streams_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Event streams: execute tests>>
   end subroutine event_streams_test
 
 @ %def event_streams_test
 @
 \subsubsection{Empty event stream}
 This should set up an empty event output stream array, including
 initialization, output, and finalization (which are all no-ops).
 <<Event streams: execute tests>>=
   call test (event_streams_1, "event_streams_1", &
        "empty event stream array", &
        u, results)
 <<Event streams: test declarations>>=
   public :: event_streams_1
 <<Event streams: tests>>=
   subroutine event_streams_1 (u)
     integer, intent(in) :: u
     type(event_stream_array_t) :: es_array
     type(rt_data_t) :: global
     type(event_t) :: event
     type(string_t) :: sample
     type(string_t), dimension(0) :: empty_string_array
 
     write (u, "(A)")  "* Test output: event_streams_1"
     write (u, "(A)")  "*   Purpose: handle empty event stream array"
     write (u, "(A)")
 
     sample = "event_streams_1"
 
     call es_array%init (sample, empty_string_array, global)
     call es_array%output (event, 42, 1)
     call es_array%write (u)
     call es_array%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: event_streams_1"
 
   end subroutine event_streams_1
 
 @ %def event_streams_1
 @
 \subsubsection{Nontrivial event stream}
 Here we generate a trivial event and choose [[raw]] output as an entry in
 the stream array.
 <<Event streams: execute tests>>=
   call test (event_streams_2, "event_streams_2", &
        "nontrivial event stream array", &
        u, results)
 <<Event streams: test declarations>>=
   public :: event_streams_2
 <<Event streams: tests>>=
   subroutine event_streams_2 (u)
     use processes_ut, only: prepare_test_process
     integer, intent(in) :: u
     type(event_stream_array_t) :: es_array
     type(rt_data_t) :: global
     type(model_data_t), target :: model
     type(event_t), allocatable, target :: event
     type(process_t), allocatable, target :: process
     type(process_instance_t), allocatable, target :: process_instance
     type(string_t) :: sample
     type(string_t), dimension(0) :: empty_string_array
     integer :: i_prc, iostat
 
     write (u, "(A)")  "* Test output: event_streams_2"
     write (u, "(A)")  "*   Purpose: handle empty event stream array"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call model%init_test ()
 
     write (u, "(A)")  "* Generate test process event"
     write (u, "(A)")
 
     allocate (process)
     allocate (process_instance)
     call prepare_test_process (process, process_instance, model, &
          run_id = var_str ("run_test"))
     call process_instance%setup_event_data ()
 
     allocate (event)
     call event%basic_init ()
     call event%connect (process_instance, process%get_model_ptr ())
     call event%generate (1, [0.4_default, 0.4_default])
     call event%set_index (42)
     call event%evaluate_expressions ()
     call event%write (u)
 
     write (u, "(A)")
     write (u, "(A)") "* Allocate raw eio stream and write event to file"
     write (u, "(A)")
 
     sample = "event_streams_2"
 
     call es_array%init (sample, [var_str ("raw")], global)
     call es_array%output (event, 1, 1)
     call es_array%write (u)
     call es_array%final ()
 
     write (u, "(A)")
     write (u, "(A)") "* Reallocate raw eio stream for reading"
     write (u, "(A)")
 
     sample = "foo"
     call es_array%init (sample, empty_string_array, global, &
          input = var_str ("raw"), input_sample = var_str ("event_streams_2"))
     call es_array%write (u)
 
     write (u, "(A)")
     write (u, "(A)") "* Reread event"
     write (u, "(A)")
 
     call es_array%input_i_prc (i_prc, iostat)
 
     write (u, "(1x,A,I0)")  "i_prc = ", i_prc
     write (u, "(A)")
     call es_array%input_event (event, iostat)
     call es_array%final ()
 
     call event%write (u)
 
     call global%final ()
 
     call model%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: event_streams_2"
 
   end subroutine event_streams_2
 
 @ %def event_streams_2
 @
 \subsubsection{Switch in/out}
 Here we generate an event file and test switching from writing to
 reading when the file is exhausted.
 <<Event streams: execute tests>>=
   call test (event_streams_3, "event_streams_3", &
        "switch input/output", &
        u, results)
 <<Event streams: test declarations>>=
   public :: event_streams_3
 <<Event streams: tests>>=
   subroutine event_streams_3 (u)
     use processes_ut, only: prepare_test_process
     integer, intent(in) :: u
     type(event_stream_array_t) :: es_array
     type(rt_data_t) :: global
     type(model_data_t), target :: model
     type(event_t), allocatable, target :: event
     type(process_t), allocatable, target :: process
     type(process_instance_t), allocatable, target :: process_instance
     type(string_t) :: sample
     type(string_t), dimension(0) :: empty_string_array
     integer :: i_prc, iostat
 
     write (u, "(A)")  "* Test output: event_streams_3"
     write (u, "(A)")  "*   Purpose: handle in/out switching"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call model%init_test ()
 
     write (u, "(A)")  "* Generate test process event"
     write (u, "(A)")
 
     allocate (process)
     allocate (process_instance)
     call prepare_test_process (process, process_instance, model, &
          run_id = var_str ("run_test"))
     call process_instance%setup_event_data ()
 
     allocate (event)
     call event%basic_init ()
     call event%connect (process_instance, process%get_model_ptr ())
     call event%generate (1, [0.4_default, 0.4_default])
     call event%increment_index ()
     call event%evaluate_expressions ()
 
     write (u, "(A)") "* Allocate raw eio stream and write event to file"
     write (u, "(A)")
 
     sample = "event_streams_3"
 
     call es_array%init (sample, [var_str ("raw")], global)
     call es_array%output (event, 1, 1)
     call es_array%write (u)
     call es_array%final ()
 
     write (u, "(A)")
     write (u, "(A)") "* Reallocate raw eio stream for reading"
     write (u, "(A)")
 
     call es_array%init (sample, empty_string_array, global, &
          input = var_str ("raw"))
     call es_array%write (u)
 
     write (u, "(A)")
     write (u, "(A)") "* Reread event"
     write (u, "(A)")
 
     call es_array%input_i_prc (i_prc, iostat)
     call es_array%input_event (event, iostat)
 
     write (u, "(A)") "* Attempt to read another event (fail), then generate"
     write (u, "(A)")
 
     call es_array%input_i_prc (i_prc, iostat)
     if (iostat < 0) then
        call es_array%switch_inout ()
        call event%generate (1, [0.3_default, 0.3_default])
        call event%increment_index ()
        call event%evaluate_expressions ()
        call es_array%output (event, 1, 2)
     end if
     call es_array%write (u)
     call es_array%final ()
 
     write (u, "(A)")
     call event%write (u)
 
     write (u, "(A)")
     write (u, "(A)") "* Reallocate raw eio stream for reading"
     write (u, "(A)")
 
     call es_array%init (sample, empty_string_array, global, &
          input = var_str ("raw"))
     call es_array%write (u)
 
     write (u, "(A)")
     write (u, "(A)") "* Reread two events and display 2nd event"
     write (u, "(A)")
 
     call es_array%input_i_prc (i_prc, iostat)
     call es_array%input_event (event, iostat)
     call es_array%input_i_prc (i_prc, iostat)
 
     call es_array%input_event (event, iostat)
     call es_array%final ()
 
     call event%write (u)
 
     call global%final ()
 
     call model%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: event_streams_3"
 
   end subroutine event_streams_3
 
 @ %def event_streams_3
 @
 \subsubsection{Checksum}
 Here we generate an event file and repeat twice, once with identical
 parameters and once with modified parameters.
 <<Event streams: execute tests>>=
   call test (event_streams_4, "event_streams_4", &
        "check MD5 sum", &
        u, results)
 <<Event streams: test declarations>>=
   public :: event_streams_4
 <<Event streams: tests>>=
   subroutine event_streams_4 (u)
     integer, intent(in) :: u
     type(event_stream_array_t) :: es_array
     type(rt_data_t) :: global
     type(process_t), allocatable, target :: process
     type(string_t) :: sample
     type(string_t), dimension(0) :: empty_string_array
     type(event_sample_data_t) :: data
 
     write (u, "(A)")  "* Test output: event_streams_4"
     write (u, "(A)")  "*   Purpose: handle in/out switching"
     write (u, "(A)")
 
     write (u, "(A)")  "* Generate test process event"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call global%set_log (var_str ("?check_event_file"), &
          .true., is_known = .true.)
 
     allocate (process)
 
     write (u, "(A)") "* Allocate raw eio stream for writing"
     write (u, "(A)")
 
     sample = "event_streams_4"
     data%md5sum_cfg = "1234567890abcdef1234567890abcdef"
 
     call es_array%init (sample, [var_str ("raw")], global, data)
     call es_array%write (u)
     call es_array%final ()
 
     write (u, "(A)")
     write (u, "(A)") "* Reallocate raw eio stream for reading"
     write (u, "(A)")
 
     call es_array%init (sample, empty_string_array, global, &
          data, input = var_str ("raw"))
     call es_array%write (u)
     call es_array%final ()
 
     write (u, "(A)")
     write (u, "(A)") "* Reallocate modified raw eio stream for reading (fail)"
     write (u, "(A)")
 
     data%md5sum_cfg = "1234567890______1234567890______"
     call es_array%init (sample, empty_string_array, global, &
          data, input = var_str ("raw"))
     call es_array%write (u)
     call es_array%final ()
 
     write (u, "(A)")
     write (u, "(A)") "* Repeat ignoring checksum"
     write (u, "(A)")
 
     call global%set_log (var_str ("?check_event_file"), &
          .false., is_known = .true.)
     call es_array%init (sample, empty_string_array, global, &
          data, input = var_str ("raw"))
     call es_array%write (u)
     call es_array%final ()
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: event_streams_4"
 
   end subroutine event_streams_4
 
 @ %def event_streams_4
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Restricted Subprocesses}
 This module provides an automatic means to construct restricted subprocesses
 of a current process object.  A restricted subprocess has the same initial and
 final state as the current process, but a restricted set of Feynman graphs.
 
 The actual application extracts the set of resonance histories that apply to
 the process and uses this to construct subprocesses that are restricted to one
 of those histories, respectively.  The resonance histories are derived from
 the phase-space setup.  This implies that the method is tied to the OMega
 matrix element generator and to the wood phase space method.
 
 The processes are collected in a new process library that is generated
 on-the-fly.
 
 The [[resonant_subprocess_t]] object is intended as a component of the event
 record, which manages all operations regarding resonance handling.
 
 The run-time calculations are delegated to an event transform
 ([[evt_resonance_t]]), as a part of the event transform chain.  The transform
 selects one (or none) of the resonance histories, given the momentum
 configuration, computes matrix elements and inserts resonances into the
 particle set.
 <<[[restricted_subprocesses.f90]]>>=
 <<File header>>
 
 module restricted_subprocesses
 
 <<Use kinds>>
 <<Use strings>>
   use diagnostics, only: msg_message, msg_fatal, msg_bug
   use diagnostics, only: signal_is_pending
   use io_units, only: given_output_unit
   use format_defs, only: FMT_14, FMT_19
   use string_utils, only: str
   use lorentz, only: vector4_t
   use particle_specifiers, only: prt_spec_t
   use particles, only: particle_set_t
   use resonances, only: resonance_history_t, resonance_history_set_t
   use variables, only: var_list_t
   use models, only: model_t
   use process_libraries, only: process_component_def_t
   use process_libraries, only: process_library_t
   use process_libraries, only: STAT_ACTIVE
   use prclib_stacks, only: prclib_entry_t
   use event_transforms, only: evt_t
   use resonance_insertion, only: evt_resonance_t
   use rt_data, only: rt_data_t
   use compilations, only: compile_library
   use process_configurations, only: process_configuration_t
   use process, only: process_t, process_ptr_t
   use instances, only: process_instance_t, process_instance_ptr_t
   use integrations, only: integrate_process
 
 <<Use mpi f08>>
 
 <<Standard module head>>
 
 <<Restricted subprocesses: public>>
 
 <<Restricted subprocesses: types>>
 
 <<Restricted subprocesses: interfaces>>
 
 contains
 
 <<Restricted subprocesses: procedures>>
 
 end module restricted_subprocesses
 @ %def restricted_subprocesses
 @
 \subsection{Process configuration}
 We extend the [[process_configuration_t]] by another method for initialization
 that takes into account a resonance history.
 <<Restricted subprocesses: public>>=
   public :: restricted_process_configuration_t
 <<Restricted subprocesses: types>>=
   type, extends (process_configuration_t) :: restricted_process_configuration_t
      private
    contains
    <<Restricted subprocesses: restricted process configuration: TBP>>
   end type restricted_process_configuration_t
 
 @ %def restricted_process_configuration_t
 @
 Resonance history as an argument.  We use it to override the [[restrictions]]
 setting in a local variable list.  Since we can construct the restricted
 process only by using OMega, we enforce it as the ME method.  Other settings
 are taken from the variable list.  The model will most likely be set, but we
 insert a safeguard just in case.
 
 Also, the resonant subprocess should not itself spawn resonant
 subprocesses, so we unset [[?resonance_history]].
 
 We have to create a local copy of the model here, via pointer
 allocation.  The reason is that the model as stored (via pointer) in
 the base type will be finalized and deallocated.
 
 The current implementation will generate a LO process, the optional
 [[nlo_process]] is unset.  (It is not obvious
 whether the construction makes sense beyond LO.)
 <<Restricted subprocesses: restricted process configuration: TBP>>=
   procedure :: init_resonant_process
 <<Restricted subprocesses: procedures>>=
   subroutine init_resonant_process &
        (prc_config, prc_name, prt_in, prt_out, res_history, model, var_list)
     class(restricted_process_configuration_t), intent(out) :: prc_config
     type(string_t), intent(in) :: prc_name
     type(prt_spec_t), dimension(:), intent(in) :: prt_in
     type(prt_spec_t), dimension(:), intent(in) :: prt_out
     type(resonance_history_t), intent(in) :: res_history
     type(model_t), intent(in), target :: model
     type(var_list_t), intent(in), target :: var_list
     type(model_t), pointer :: local_model
     type(var_list_t) :: local_var_list
     allocate (local_model)
     call local_model%init_instance (model)
     call local_var_list%link (var_list)
     call local_var_list%append_string (var_str ("$model_name"), &
          sval = local_model%get_name (), &
          intrinsic=.true.)
     call local_var_list%append_string (var_str ("$method"), &
          sval = var_str ("omega"), &
          intrinsic=.true.)
     call local_var_list%append_string (var_str ("$restrictions"), &
          sval = res_history%as_omega_string (size (prt_in)), &
          intrinsic = .true.)
     call local_var_list%append_log (var_str ("?resonance_history"), &
          lval = .false., &
          intrinsic = .true.)
     call prc_config%init (prc_name, size (prt_in), 1, &
          local_model, local_var_list)
     call prc_config%setup_component (1, &
          prt_in, prt_out, &
          local_model, local_var_list)
   end subroutine init_resonant_process
 
 @ %def init_resonant_process
 @
 \subsection{Resonant-subprocess set manager}
 This data type enables generation of a library of resonant subprocesses for a
 given master process, and it allows for convenient access.  The matrix
 elements from the subprocesses can be used as channel weights to activate a
 selector, which then returns a preferred channel via some random number
 generator.
 <<Restricted subprocesses: public>>=
   public :: resonant_subprocess_set_t
 <<Restricted subprocesses: types>>=
   type :: resonant_subprocess_set_t
      private
      integer, dimension(:), allocatable :: n_history
      type(resonance_history_set_t), dimension(:), allocatable :: res_history_set
      logical :: lib_active = .false.
      type(string_t) :: libname
      type(string_t), dimension(:), allocatable :: proc_id
      type(process_ptr_t), dimension(:), allocatable :: subprocess
      type(process_instance_ptr_t), dimension(:), allocatable :: instance
      logical :: filled = .false.
      type(evt_resonance_t), pointer :: evt => null ()
    contains
    <<Restricted subprocesses: resonant subprocess set: TBP>>
   end type resonant_subprocess_set_t
 
 @ %def resonant_subprocess_set_t
 @ Output
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: write => resonant_subprocess_set_write
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_write (prc_set, unit, testflag)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: testflag
     logical :: truncate
     integer :: u, i
     u = given_output_unit (unit)
     truncate = .false.;  if (present (testflag))  truncate = testflag
     write (u, "(1x,A)")  "Resonant subprocess set:"
     if (allocated (prc_set%n_history)) then
        if (any (prc_set%n_history > 0)) then
           do i = 1, size (prc_set%n_history)
              if (prc_set%n_history(i) > 0) then
                 write (u, "(1x,A,I0)")  "Component #", i
                 call prc_set%res_history_set(i)%write (u, indent=1)
              end if
           end do
           if (prc_set%lib_active) then
              write (u, "(3x,A,A,A)")  "Process library = '", &
                   char (prc_set%libname), "'"
           else
              write (u, "(3x,A)")  "Process library: [inactive]"
           end if
           if (associated (prc_set%evt)) then
              if (truncate) then
                 write (u, "(3x,A,1x," // FMT_14 // ")") &
                      "Process sqme =", prc_set%get_master_sqme ()
              else
                 write (u, "(3x,A,1x," // FMT_19 // ")") &
                      "Process sqme =", prc_set%get_master_sqme ()
              end if
           end if
           if (associated (prc_set%evt)) then
              write (u, "(3x,A)")  "Event transform: associated"
              write (u, "(2x)", advance="no")
              call prc_set%evt%write_selector (u, testflag)
           else
              write (u, "(3x,A)")  "Event transform: not associated"
           end if
        else
           write (u, "(2x,A)")  "[empty]"
        end if
     else
        write (u, "(3x,A)")  "[not allocated]"
     end if
   end subroutine resonant_subprocess_set_write
 
 @ %def resonant_subprocess_set_write
 @
 \subsection{Resonance history set}
 Initialize subprocess set with an array of pre-created resonance
 history sets.
 
 Safeguard: if there are no resonances in the input, initialize the local set
 as empty, but complete.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: init => resonant_subprocess_set_init
   procedure :: fill_resonances => resonant_subprocess_set_fill_resonances
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_init (prc_set, n_component)
     class(resonant_subprocess_set_t), intent(out) :: prc_set
     integer, intent(in) :: n_component
     allocate (prc_set%res_history_set (n_component))
     allocate (prc_set%n_history (n_component), source = 0)
   end subroutine resonant_subprocess_set_init
 
   subroutine resonant_subprocess_set_fill_resonances (prc_set, &
        res_history_set, i_component)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     type(resonance_history_set_t), intent(in) :: res_history_set
     integer, intent(in) :: i_component
     prc_set%n_history(i_component) = res_history_set%get_n_history ()
     if (prc_set%n_history(i_component) > 0) then
        prc_set%res_history_set(i_component) = res_history_set
     else
        call prc_set%res_history_set(i_component)%init (initial_size = 0)
        call prc_set%res_history_set(i_component)%freeze ()
     end if
   end subroutine resonant_subprocess_set_fill_resonances
 
 @ %def resonant_subprocess_set_init
 @ %def resonant_subprocess_set_fill_resonances
 @ Return the resonance history set.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: get_resonance_history_set &
        => resonant_subprocess_set_get_resonance_history_set
 <<Restricted subprocesses: procedures>>=
   function resonant_subprocess_set_get_resonance_history_set (prc_set) &
        result (res_history_set)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     type(resonance_history_set_t), dimension(:), allocatable :: res_history_set
     res_history_set = prc_set%res_history_set
   end function resonant_subprocess_set_get_resonance_history_set
 
 @ %def resonant_subprocess_set_get_resonance_history_set
 @
 \subsection{Library for the resonance history set}
 The recommended library name: append [[_R]] to the process name.
 <<Restricted subprocesses: public>>=
   public :: get_libname_res
 <<Restricted subprocesses: procedures>>=
   elemental function get_libname_res (proc_id) result (libname)
     type(string_t), intent(in) :: proc_id
     type(string_t) :: libname
     libname = proc_id // "_R"
   end function get_libname_res
 
 @ %def get_libname_res
 @ Here we scan the global process library whether any
 processes require resonant subprocesses to be constructed.  If yes,
 create process objects with phase space and construct the process
 libraries as usual.  Then append the library names to the array.
 
 The temporary integration objects should carry the [[phs_only]]
 flag.  We set this in the local environment.
 
 Once a process object with resonance histories (derived from phase
 space) has been created, we extract the resonance histories and use
 them, together with the process definition, to create the new library.
 
 Finally, compile the library.
 <<Restricted subprocesses: public>>=
   public :: spawn_resonant_subprocess_libraries
 <<Restricted subprocesses: procedures>>=
   subroutine spawn_resonant_subprocess_libraries &
        (libname, local, global, libname_res)
     type(string_t), intent(in) :: libname
     type(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(inout), target :: global
     type(string_t), dimension(:), allocatable, intent(inout) :: libname_res
     type(process_library_t), pointer :: lib
     type(string_t), dimension(:), allocatable :: process_id_res
     type(process_t), pointer :: process
     type(resonance_history_set_t) :: res_history_set
     type(process_component_def_t), pointer :: process_component_def
     logical :: phs_only_saved, exist
     integer :: i_proc, i_component
     lib => global%prclib_stack%get_library_ptr (libname)
     call lib%get_process_id_req_resonant (process_id_res)
     if (size (process_id_res) > 0) then
        call msg_message ("Creating resonant-subprocess libraries &
             &for library '" // char (libname) // "'")
        libname_res = get_libname_res (process_id_res)
        phs_only_saved = local%var_list%get_lval (var_str ("?phs_only"))
        call local%var_list%set_log &
             (var_str ("?phs_only"), .true., is_known=.true.)
        do i_proc = 1, size (process_id_res)
           associate (proc_id => process_id_res (i_proc))
             call msg_message ("Process '" // char (proc_id) // "': &
                  &constructing phase space for resonance structure")
             call integrate_process (proc_id, local, global)
             process => global%process_stack%get_process_ptr (proc_id)
             call create_library (libname_res(i_proc), global, exist)
             if (.not. exist) then
                do i_component = 1, process%get_n_components ()
                   call process%extract_resonance_history_set &
                        (res_history_set, i_component = i_component)
                   process_component_def &
                        => process%get_component_def_ptr (i_component)
                   call add_to_library (libname_res(i_proc), &
                        res_history_set, &
                        process_component_def%get_prt_spec_in (), &
                        process_component_def%get_prt_spec_out (), &
                        global)
                end do
                call msg_message ("Process library '" &
                     // char (libname_res(i_proc)) &
                     // "': created")
             end if
             call global%update_prclib (lib)
           end associate
        end do
        call local%var_list%set_log &
             (var_str ("?phs_only"), phs_only_saved, is_known=.true.)
     end if
   end subroutine spawn_resonant_subprocess_libraries
     
 @ %def spawn_resonant_subprocess_libraries
 @ This is another version of the library constructor, bound to a
 restricted-subprocess set object.  Create the appropriate
 process library, add processes, and close the library.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: create_library => resonant_subprocess_set_create_library
   procedure :: add_to_library => resonant_subprocess_set_add_to_library
   procedure :: freeze_library => resonant_subprocess_set_freeze_library
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_create_library (prc_set, &
        libname, global, exist)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     type(string_t), intent(in) :: libname
     type(rt_data_t), intent(inout), target :: global
     logical, intent(out) :: exist
     prc_set%libname = libname
     call create_library (prc_set%libname, global, exist)
   end subroutine resonant_subprocess_set_create_library
 
   subroutine resonant_subprocess_set_add_to_library (prc_set, &
        i_component, prt_in, prt_out, global)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     integer, intent(in) :: i_component
     type(prt_spec_t), dimension(:), intent(in) :: prt_in
     type(prt_spec_t), dimension(:), intent(in) :: prt_out
     type(rt_data_t), intent(inout), target :: global
     call add_to_library (prc_set%libname, &
          prc_set%res_history_set(i_component), &
          prt_in, prt_out, global)
   end subroutine resonant_subprocess_set_add_to_library
 
   subroutine resonant_subprocess_set_freeze_library (prc_set, global)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     type(rt_data_t), intent(inout), target :: global
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     lib => global%prclib_stack%get_library_ptr (prc_set%libname)
     call lib%get_process_id_list (prc_set%proc_id)
     prc_set%lib_active = .true.
   end subroutine resonant_subprocess_set_freeze_library
 
 @ %def resonant_subprocess_set_create_library
 @ %def resonant_subprocess_set_add_to_library
 @ %def resonant_subprocess_set_freeze_library
 @ The common parts of the procedures above: (i) create a new process
 library or recover it, (ii) for each history, create a
 process configuration and record it.
 <<Restricted subprocesses: procedures>>=
   subroutine create_library (libname, global, exist)
     type(string_t), intent(in) :: libname
     type(rt_data_t), intent(inout), target :: global
     logical, intent(out) :: exist
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     type(resonance_history_t) :: res_history
     type(string_t), dimension(:), allocatable :: proc_id
     type(restricted_process_configuration_t) :: prc_config
     integer :: i
     lib => global%prclib_stack%get_library_ptr (libname)
     exist = associated (lib)
     if (.not. exist) then
        call msg_message ("Creating library for resonant subprocesses '" &
             // char (libname) // "'")
        allocate (lib_entry)
        call lib_entry%init (libname)
        lib => lib_entry%process_library_t
        call global%add_prclib (lib_entry)
     else
        call msg_message ("Using library for resonant subprocesses '" &
             // char (libname) // "'")
        call global%update_prclib (lib)
     end if
   end subroutine create_library
   
   subroutine add_to_library (libname, res_history_set, prt_in, prt_out, global)
     type(string_t), intent(in) :: libname
     type(resonance_history_set_t), intent(in) :: res_history_set
     type(prt_spec_t), dimension(:), intent(in) :: prt_in
     type(prt_spec_t), dimension(:), intent(in) :: prt_out
     type(rt_data_t), intent(inout), target :: global
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     type(resonance_history_t) :: res_history
     type(string_t), dimension(:), allocatable :: proc_id
     type(restricted_process_configuration_t) :: prc_config
     integer :: n0, i
     lib => global%prclib_stack%get_library_ptr (libname)
     if (associated (lib)) then
        n0 = lib%get_n_processes ()
        allocate (proc_id (res_history_set%get_n_history ()))
        do i = 1, size (proc_id)
           proc_id(i) = libname // str (n0 + i)
           res_history = res_history_set%get_history(i)
           call prc_config%init_resonant_process (proc_id(i), &
                prt_in, prt_out, &
                res_history, &
                global%model, global%var_list)
           call msg_message ("Resonant subprocess #" &
                // char (str(n0+i)) // ": " &
                // char (res_history%as_omega_string (size (prt_in))))
           call prc_config%record (global)
           if (signal_is_pending ())  return
        end do
     else
        call msg_bug ("Adding subprocesses: library '" &
             // char (libname) // "' not found")
     end if
   end subroutine add_to_library
   
 @ %def create_library
 @ %def add_to_library
 @ Compile the generated library, required settings taken from the
 [[global]] data set.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: compile_library => resonant_subprocess_set_compile_library
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_compile_library (prc_set, global)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     type(rt_data_t), intent(inout), target :: global
     type(process_library_t), pointer :: lib
     lib => global%prclib_stack%get_library_ptr (prc_set%libname)
     if (lib%get_status () < STAT_ACTIVE) then
        call compile_library (prc_set%libname, global)
     end if
   end subroutine resonant_subprocess_set_compile_library
 
 @ %def resonant_subprocess_set_compile_library
 @ Check if the library has been created / the process has been evaluated.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: is_active => resonant_subprocess_set_is_active
 <<Restricted subprocesses: procedures>>=
   function resonant_subprocess_set_is_active (prc_set) result (flag)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     logical :: flag
     flag = prc_set%lib_active
   end function resonant_subprocess_set_is_active
 
 @ %def resonant_subprocess_set_is_active
 @ Return number of generated process objects, library, and process IDs.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: get_n_process => resonant_subprocess_set_get_n_process
   procedure :: get_libname => resonant_subprocess_set_get_libname
   procedure :: get_proc_id => resonant_subprocess_set_get_proc_id
 <<Restricted subprocesses: procedures>>=
   function resonant_subprocess_set_get_n_process (prc_set) result (n)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     integer :: n
     if (prc_set%lib_active) then
        n = size (prc_set%proc_id)
     else
        n = 0
     end if
   end function resonant_subprocess_set_get_n_process
 
   function resonant_subprocess_set_get_libname (prc_set) result (libname)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     type(string_t) :: libname
     if (prc_set%lib_active) then
        libname = prc_set%libname
     else
        libname = ""
     end if
   end function resonant_subprocess_set_get_libname
 
   function resonant_subprocess_set_get_proc_id (prc_set, i) result (proc_id)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     integer, intent(in) :: i
     type(string_t) :: proc_id
     if (allocated (prc_set%proc_id)) then
        proc_id = prc_set%proc_id(i)
     else
        proc_id = ""
     end if
   end function resonant_subprocess_set_get_proc_id
 
 @ %def resonant_subprocess_set_get_n_process
 @ %def resonant_subprocess_set_get_libname
 @ %def resonant_subprocess_set_get_proc_id
 @
 \subsection{Process objects and instances}
 Prepare process objects for all entries in the resonant-subprocesses
 library.  The process objects are appended to the global process
 stack.  A local environment can be used where we place temporary
 variable settings that affect process-object generation.  We
 initialize the processes, such that we can evaluate matrix elements,
 but we do not need to integrate them.
 
 The internal procedure [[prepare_process]] is an abridged version of
 the procedure with this name in the [[simulations]] module.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: prepare_process_objects &
        => resonant_subprocess_set_prepare_process_objects
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_prepare_process_objects &
        (prc_set, local, global)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     type(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(inout), optional, target :: global
     type(rt_data_t), pointer :: current
     type(process_library_t), pointer :: lib
     type(string_t) :: proc_id, libname_cur, libname_res
     integer :: i, n
     if (.not. prc_set%is_active ())  return
     if (present (global)) then
        current => global
     else
        current => local
     end if
     libname_cur = current%prclib%get_name ()
     libname_res = prc_set%get_libname ()
     lib => current%prclib_stack%get_library_ptr (libname_res)
     if (associated (lib))  call current%update_prclib (lib)
     call local%set_string (var_str ("$phs_method"), &
             var_str ("none"), is_known = .true.)
     call local%set_string (var_str ("$integration_method"), &
             var_str ("none"), is_known = .true.)
     n = prc_set%get_n_process ()
     allocate (prc_set%subprocess (n))
     do i = 1, n
        proc_id = prc_set%get_proc_id (i)
        call prepare_process (prc_set%subprocess(i)%p, proc_id)
        if (signal_is_pending ())  return
     end do
     lib => current%prclib_stack%get_library_ptr (libname_cur)
     if (associated (lib))  call current%update_prclib (lib)
   contains
     subroutine prepare_process (process, process_id)
       type(process_t), pointer, intent(out) :: process
       type(string_t), intent(in) :: process_id
       call msg_message ("Simulate: initializing resonant subprocess '" &
                // char (process_id) // "'")
       if (present (global)) then
          call integrate_process (process_id, local, global, &
               init_only = .true.)
       else
          call integrate_process (process_id, local, local_stack = .true., &
               init_only = .true.)
       end if
       process => current%process_stack%get_process_ptr (process_id)
       if (.not. associated (process)) then
          call msg_fatal ("Simulate: resonant subprocess '" &
                // char (process_id) // "' could not be initialized: aborting")
       end if
     end subroutine prepare_process
   end subroutine resonant_subprocess_set_prepare_process_objects
 
 @ %def resonant_subprocess_set_prepare_process_objects
 @ Workspace for the resonant subprocesses.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: prepare_process_instances &
        => resonant_subprocess_set_prepare_process_instances
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_prepare_process_instances (prc_set, global)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     type(rt_data_t), intent(in), target :: global
     integer :: i, n
     if (.not. prc_set%is_active ())  return
     n = size (prc_set%subprocess)
     allocate (prc_set%instance (n))
     do i = 1, n
        allocate (prc_set%instance(i)%p)
        call prc_set%instance(i)%p%init (prc_set%subprocess(i)%p)
        call prc_set%instance(i)%p%setup_event_data (global%model)
     end do
   end subroutine resonant_subprocess_set_prepare_process_instances
 
 @ %def resonant_subprocess_set_prepare_process_instances
 @
 \subsection{Event transform connection}
 The idea is that the resonance-insertion event transform has been
 allocated somewhere (namely, in the standard event-transform chain),
 but we maintain a link such that we can inject matrix-element results
 event by event.  The event transform holds a selector, to choose one
 of the resonance histories (or none), and it manages resonance
 insertion for the particle set.
 
 The data that the event transform requires can be provided here.  The
 resonance history set has already been assigned with the [[dispatch]]
 initializer.  Here, we supply the set of subprocess instances that we
 have generated (see above).  The master-process instance is set
 when we [[connect]] the transform by the standard method.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: connect_transform => &
        resonant_subprocess_set_connect_transform
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_connect_transform (prc_set, evt)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     class(evt_t), intent(in), target :: evt
     select type (evt)
     type is (evt_resonance_t)
        prc_set%evt => evt
        call prc_set%evt%set_subprocess_instances (prc_set%instance)
     class default
        call msg_bug ("Resonant subprocess set: event transform has wrong type")
     end select
   end subroutine resonant_subprocess_set_connect_transform
 
 @ %def resonant_subprocess_set_connect_transform
 @ Set the on-shell limit value in the connected transform.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: set_on_shell_limit => resonant_subprocess_set_on_shell_limit
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_on_shell_limit (prc_set, on_shell_limit)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     real(default), intent(in) :: on_shell_limit
     call prc_set%evt%set_on_shell_limit (on_shell_limit)
   end subroutine resonant_subprocess_set_on_shell_limit
 
 @ %def resonant_subprocess_set_on_shell_limit
 @ Set the Gaussian turnoff parameter in the connected transform.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: set_on_shell_turnoff => resonant_subprocess_set_on_shell_turnoff
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_on_shell_turnoff &
        (prc_set, on_shell_turnoff)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     real(default), intent(in) :: on_shell_turnoff
     call prc_set%evt%set_on_shell_turnoff (on_shell_turnoff)
   end subroutine resonant_subprocess_set_on_shell_turnoff
 
 @ %def resonant_subprocess_set_on_shell_turnoff
 @ Reweight (suppress) the background contribution probability, for the
 kinematics where a resonance history is active.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: set_background_factor &
        => resonant_subprocess_set_background_factor
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_background_factor &
        (prc_set, background_factor)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     real(default), intent(in) :: background_factor
     call prc_set%evt%set_background_factor (background_factor)
   end subroutine resonant_subprocess_set_background_factor
 
 @ %def resonant_subprocess_set_background_factor
 @
 \subsection{Wrappers for runtime calculations}
 All runtime calculations are delegated to the event transform.  The
 following procedures are essentially redundant wrappers.  We retain
 them for a unit test below.
 
 Debugging aid:
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: dump_instances => resonant_subprocess_set_dump_instances
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_dump_instances (prc_set, unit, testflag)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: testflag
     integer :: i, n, u
     u = given_output_unit (unit)
     write (u, "(A)")  "*** Process instances of resonant subprocesses"
     write (u, *)
     n = size (prc_set%subprocess)
     do i = 1, n
        associate (instance => prc_set%instance(i)%p)
          call instance%write (u, testflag)
          write (u, *)
          write (u, *)
        end associate
     end do
   end subroutine resonant_subprocess_set_dump_instances
 
 @ %def resonant_subprocess_set_dump_instances
 @ Inject the current kinematics configuration, reading from the
 previous event transform or from the process instance.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: fill_momenta => resonant_subprocess_set_fill_momenta
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_fill_momenta (prc_set)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     integer :: i, n
     call prc_set%evt%fill_momenta ()
   end subroutine resonant_subprocess_set_fill_momenta
 
 @ %def resonant_subprocess_set_fill_momenta
 @ Determine the indices of the resonance histories that can be
 considered on-shell for the current kinematics.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: determine_on_shell_histories &
        => resonant_subprocess_set_determine_on_shell_histories
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_determine_on_shell_histories &
        (prc_set, i_component, index_array)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     integer, intent(in) :: i_component
     integer, dimension(:), allocatable, intent(out) :: index_array
     call prc_set%evt%determine_on_shell_histories (index_array)
   end subroutine resonant_subprocess_set_determine_on_shell_histories
 
 @ %def resonant_subprocess_set_determine_on_shell_histories
 @ Evaluate selected subprocesses.  (In actual operation, the ones that
 have been tagged as on-shell.)
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: evaluate_subprocess &
        => resonant_subprocess_set_evaluate_subprocess
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_evaluate_subprocess (prc_set, index_array)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     integer, dimension(:), intent(in) :: index_array
     call prc_set%evt%evaluate_subprocess (index_array)
   end subroutine resonant_subprocess_set_evaluate_subprocess
 
 @ %def resonant_subprocess_set_evaluate_subprocess
 @ Extract the matrix elements of the master process / the resonant
 subprocesses.  After the previous routine has been executed, they
 should be available and stored in the corresponding process instances.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: get_master_sqme &
        => resonant_subprocess_set_get_master_sqme
   procedure :: get_subprocess_sqme &
        => resonant_subprocess_set_get_subprocess_sqme
 <<Restricted subprocesses: procedures>>=
   function resonant_subprocess_set_get_master_sqme (prc_set) result (sqme)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     real(default) :: sqme
     sqme = prc_set%evt%get_master_sqme ()
   end function resonant_subprocess_set_get_master_sqme
 
   subroutine resonant_subprocess_set_get_subprocess_sqme (prc_set, sqme)
     class(resonant_subprocess_set_t), intent(in) :: prc_set
     real(default), dimension(:), intent(inout) :: sqme
     integer :: i
     call prc_set%evt%get_subprocess_sqme (sqme)
   end subroutine resonant_subprocess_set_get_subprocess_sqme
 
 @ %def resonant_subprocess_set_get_master_sqme
 @ %def resonant_subprocess_set_get_subprocess_sqme
 @ We use the calculations of resonant matrix elements to determine
 probabilities for all resonance configurations.
 <<Restricted subprocesses: resonant subprocess set: TBP>>=
   procedure :: compute_probabilities &
        => resonant_subprocess_set_compute_probabilities
 <<Restricted subprocesses: procedures>>=
   subroutine resonant_subprocess_set_compute_probabilities (prc_set, prob_array)
     class(resonant_subprocess_set_t), intent(inout) :: prc_set
     real(default), dimension(:), allocatable, intent(out) :: prob_array
     integer, dimension(:), allocatable :: index_array
     real(default) :: sqme, sqme_sum, sqme_bg
     real(default), dimension(:), allocatable :: sqme_res
     integer :: n
     n = size (prc_set%subprocess)
     allocate (prob_array (0:n), source = 0._default)
     call prc_set%evt%compute_probabilities ()
     call prc_set%evt%get_selector_weights (prob_array)
   end subroutine resonant_subprocess_set_compute_probabilities
 
 @ %def resonant_subprocess_set_compute_probabilities
 @
 \subsection{Unit tests}
 Test module, followed by the stand-alone unit-test procedures.
 <<[[restricted_subprocesses_ut.f90]]>>=
 <<File header>>
 
 module restricted_subprocesses_ut
   use unit_tests
   use restricted_subprocesses_uti
 
 <<Standard module head>>
 
 <<Restricted subprocesses: public test>>
 
 contains
 
 <<Restricted subprocesses: test driver>>
 
 end module restricted_subprocesses_ut
 @ %def restricted_subprocesses_ut
 @
 <<[[restricted_subprocesses_uti.f90]]>>=
 <<File header>>
 
 module restricted_subprocesses_uti
 
 <<Use kinds>>
 <<Use strings>>
   use io_units, only: free_unit
   use format_defs, only: FMT_10, FMT_12
   use lorentz, only: vector4_t, vector3_moving, vector4_moving
   use particle_specifiers, only: new_prt_spec
   use process_libraries, only: process_library_t
   use resonances, only: resonance_info_t
   use resonances, only: resonance_history_t
   use resonances, only: resonance_history_set_t
   use state_matrices, only: FM_IGNORE_HELICITY
   use particles, only: particle_set_t
   use model_data, only: model_data_t
   use models, only: syntax_model_file_init, syntax_model_file_final
   use models, only: model_t
   use rng_base_ut, only: rng_test_factory_t
   use mci_base, only: mci_t
   use mci_none, only: mci_none_t
   use phs_base, only: phs_config_t
   use phs_forests, only: syntax_phs_forest_init, syntax_phs_forest_final
   use phs_wood, only: phs_wood_config_t
   use process_libraries, only: process_def_entry_t
   use process_libraries, only: process_component_def_t
   use prclib_stacks, only: prclib_entry_t
   use prc_core_def, only: prc_core_def_t
   use prc_omega, only: omega_def_t
   use process, only: process_t
   use instances, only: process_instance_t
   use process_stacks, only: process_entry_t
   use event_transforms, only: evt_trivial_t
   use resonance_insertion, only: evt_resonance_t
   use integrations, only: integrate_process
   use rt_data, only: rt_data_t
 
   use restricted_subprocesses
 
 <<Standard module head>>
 
 <<Restricted subprocesses: test declarations>>
 
 <<Restricted subprocesses: test auxiliary types>>
 
 <<Restricted subprocesses: public test auxiliary>>
 
 contains
 
 <<Restricted subprocesses: tests>>
 
 <<Restricted subprocesses: test auxiliary>>
 
 end module restricted_subprocesses_uti
 
 @ %def restricted_subprocesses_uti
 @ API: driver for the unit tests below.
 <<Restricted subprocesses: public test>>=
   public :: restricted_subprocesses_test
 <<Restricted subprocesses: test driver>>=
   subroutine restricted_subprocesses_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Restricted subprocesses: execute tests>>
   end subroutine restricted_subprocesses_test
 
 @ %def restricted_subprocesses_test
 @
 \subsubsection{subprocess configuration}
 Initialize a [[restricted_subprocess_configuration_t]] object which represents
 a given process with a defined resonance history.
 <<Restricted subprocesses: execute tests>>=
   call test (restricted_subprocesses_1, "restricted_subprocesses_1", &
        "single subprocess", &
        u, results)
 <<Restricted subprocesses: test declarations>>=
   public :: restricted_subprocesses_1
 <<Restricted subprocesses: tests>>=
   subroutine restricted_subprocesses_1 (u)
     integer, intent(in) :: u
     type(rt_data_t) :: global
     type(resonance_info_t) :: res_info
     type(resonance_history_t) :: res_history
     type(string_t) :: prc_name
     type(string_t), dimension(2) :: prt_in
     type(string_t), dimension(3) :: prt_out
     type(restricted_process_configuration_t) :: prc_config
 
     write (u, "(A)")  "* Test output: restricted_subprocesses_1"
     write (u, "(A)")  "*   Purpose: create subprocess list from resonances"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%select_model (var_str ("SM"))
 
     write (u, "(A)")  "* Create resonance history"
     write (u, "(A)")
 
     call res_info%init (3, -24, global%model, 5)
     call res_history%add_resonance (res_info)
     call res_history%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Create process configuration"
     write (u, "(A)")
 
     prc_name = "restricted_subprocesses_1_p"
     prt_in(1) = "e-"
     prt_in(2) = "e+"
     prt_out(1) = "d"
     prt_out(2) = "u"
     prt_out(3) = "W+"
 
     call prc_config%init_resonant_process (prc_name, &
          new_prt_spec (prt_in), new_prt_spec (prt_out), &
          res_history, global%model, global%var_list)
 
     call prc_config%write (u)
 
     write (u, *)
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: restricted_subprocesses_1"
 
   end subroutine restricted_subprocesses_1
 
 @ %def restricted_subprocesses_1
 @
 \subsubsection{Subprocess library configuration}
 Create a process library that represents restricted subprocesses for a given
 set of resonance histories
 <<Restricted subprocesses: execute tests>>=
   call test (restricted_subprocesses_2, "restricted_subprocesses_2", &
        "subprocess library", &
        u, results)
 <<Restricted subprocesses: test declarations>>=
   public :: restricted_subprocesses_2
 <<Restricted subprocesses: tests>>=
   subroutine restricted_subprocesses_2 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     type(resonance_info_t) :: res_info
     type(resonance_history_t), dimension(2) :: res_history
     type(resonance_history_set_t) :: res_history_set
     type(string_t) :: libname
     type(string_t), dimension(2) :: prt_in
     type(string_t), dimension(3) :: prt_out
     type(resonant_subprocess_set_t) :: prc_set
     type(process_library_t), pointer :: lib
     logical :: exist
 
     write (u, "(A)")  "* Test output: restricted_subprocesses_2"
     write (u, "(A)")  "*   Purpose: create subprocess library from resonances"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%select_model (var_str ("SM"))
 
     write (u, "(A)")  "* Create resonance histories"
     write (u, "(A)")
 
     call res_info%init (3, -24, global%model, 5)
     call res_history(1)%add_resonance (res_info)
     call res_history(1)%write (u)
 
     call res_info%init (7, 23, global%model, 5)
     call res_history(2)%add_resonance (res_info)
     call res_history(2)%write (u)
 
     call res_history_set%init ()
     call res_history_set%enter (res_history(1))
     call res_history_set%enter (res_history(2))
     call res_history_set%freeze ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Empty restricted subprocess set"
     write (u, "(A)")
 
     write (u, "(A,1x,L1)")  "active =", prc_set%is_active ()
     write (u, "(A)")
 
     call prc_set%write (u, testflag=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Fill restricted subprocess set"
     write (u, "(A)")
 
     libname = "restricted_subprocesses_2_p_R"
     prt_in(1) = "e-"
     prt_in(2) = "e+"
     prt_out(1) = "d"
     prt_out(2) = "u"
     prt_out(3) = "W+"
 
     call prc_set%init (1)
     call prc_set%fill_resonances (res_history_set, 1)
     call prc_set%create_library (libname, global, exist)
     if (.not. exist) then
        call prc_set%add_to_library (1, &
             new_prt_spec (prt_in), new_prt_spec (prt_out), &
             global)
     end if
     call prc_set%freeze_library (global)
 
     write (u, "(A,1x,L1)")  "active =", prc_set%is_active ()
     write (u, "(A)")
 
     call prc_set%write (u, testflag=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Queries"
     write (u, "(A)")
 
     write (u, "(A,1x,I0)")  "n_process =", prc_set%get_n_process ()
     write (u, "(A)")
     write (u, "(A,A,A)")  "libname = '", char (prc_set%get_libname ()), "'"
     write (u, "(A)")
     write (u, "(A,A,A)")  "proc_id(1) = '", char (prc_set%get_proc_id (1)), "'"
     write (u, "(A,A,A)")  "proc_id(2) = '", char (prc_set%get_proc_id (2)), "'"
 
 
     write (u, "(A)")
     write (u, "(A)")  "* Process library"
     write (u, "(A)")
 
     call prc_set%compile_library (global)
 
     lib => global%prclib_stack%get_library_ptr (libname)
     if (associated (lib))  call lib%write (u, libpath=.false.)
 
     write (u, *)
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: restricted_subprocesses_2"
 
   end subroutine restricted_subprocesses_2
 
 @ %def restricted_subprocesses_2
 @
 \subsubsection{Auxiliary: Test processes}
 Auxiliary subroutine that constructs the process library for the above test.
 This parallels a similar subroutine in [[processes_uti]], but this time we
 want an \oMega\ process.
 <<Restricted subprocesses: public test auxiliary>>=
   public :: prepare_resonance_test_library
 <<Restricted subprocesses: test auxiliary>>=
   subroutine prepare_resonance_test_library &
        (lib, libname, procname, model, global, u)
     type(process_library_t), target, intent(out) :: lib
     type(string_t), intent(in) :: libname
     type(string_t), intent(in) :: procname
     class(model_data_t), intent(in), pointer :: model
     type(rt_data_t), intent(in), target :: global
     integer, intent(in) :: u
     type(string_t), dimension(:), allocatable :: prt_in, prt_out
     class(prc_core_def_t), allocatable :: def
     type(process_def_entry_t), pointer :: entry
 
     call lib%init (libname)
 
     allocate (prt_in (2), prt_out (3))
     prt_in = [var_str ("e+"), var_str ("e-")]
     prt_out = [var_str ("d"), var_str ("ubar"), var_str ("W+")]
 
     allocate (omega_def_t :: def)
     select type (def)
     type is (omega_def_t)
        call def%init (model%get_name (), prt_in, prt_out, &
             ovm=.false., ufo=.false.)
     end select
     allocate (entry)
     call entry%init (procname, &
          model_name = model%get_name (), &
          n_in = 2, n_components = 1, &
          requires_resonances = .true.)
     call entry%import_component (1, n_out = size (prt_out), &
          prt_in  = new_prt_spec (prt_in), &
          prt_out = new_prt_spec (prt_out), &
          method  = var_str ("omega"), &
          variant = def)
     call entry%write (u)
 
     call lib%append (entry)
 
     call lib%configure (global%os_data)
     call lib%write_makefile (global%os_data, force = .true., verbose = .false.)
     call lib%clean (global%os_data, distclean = .false.)
     call lib%write_driver (force = .true.)
     call lib%load (global%os_data)
 
   end subroutine prepare_resonance_test_library
 
 @ %def prepare_resonance_test_library
 @
 \subsubsection{Kinematics and resonance selection}
 Prepare an actual process with resonant subprocesses.  Insert
 kinematics and apply the resonance selector in an associated event
 transform.
 <<Restricted subprocesses: execute tests>>=
   call test (restricted_subprocesses_3, "restricted_subprocesses_3", &
        "resonance kinematics and probability", &
        u, results)
 <<Restricted subprocesses: test declarations>>=
   public :: restricted_subprocesses_3
 <<Restricted subprocesses: tests>>=
   subroutine restricted_subprocesses_3 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     class(model_t), pointer :: model
     class(model_data_t), pointer :: model_data
     type(string_t) :: libname, libname_res
     type(string_t) :: procname
     type(process_component_def_t), pointer :: process_component_def
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     logical :: exist
     type(process_t), pointer :: process
     type(process_instance_t), target :: process_instance
     type(resonance_history_set_t), dimension(1) :: res_history_set
     type(resonant_subprocess_set_t) :: prc_set
     type(particle_set_t) :: pset
     real(default) :: sqrts, mw, pp
     real(default), dimension(3) :: p3
     type(vector4_t), dimension(:), allocatable :: p
     real(default), dimension(:), allocatable :: m
     integer, dimension(:), allocatable :: pdg
     real(default), dimension(:), allocatable :: sqme
     logical, dimension(:), allocatable :: mask
     real(default) :: on_shell_limit
     integer, dimension(:), allocatable :: i_array
     real(default), dimension(:), allocatable :: prob_array
     type(evt_resonance_t), target :: evt_resonance
     integer :: i, u_dump
 
     write (u, "(A)")  "* Test output: restricted_subprocesses_3"
     write (u, "(A)")  "*   Purpose: handle process and resonance kinematics"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     call global%global_init ()
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%set_log (var_str ("?resonance_history"), &
          .true., is_known = .true.)
 
     call global%select_model (var_str ("SM"))
     allocate (model)
     call model%init_instance (global%model)
     model_data => model
 
     libname = "restricted_subprocesses_3_lib"
     libname_res = "restricted_subprocesses_3_lib_res"
     procname = "restricted_subprocesses_3_p"
 
     write (u, "(A)")  "* Initialize process library and process"
     write (u, "(A)")
 
     allocate (lib_entry)
     call lib_entry%init (libname)
     lib => lib_entry%process_library_t
     call global%add_prclib (lib_entry)
 
     call prepare_resonance_test_library &
          (lib, libname, procname, model_data, global, u)
 
     call integrate_process (procname, global, &
          local_stack = .true., init_only = .true.)
 
     process => global%process_stack%get_process_ptr (procname)
 
     call process_instance%init (process)
     call process_instance%setup_event_data ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Extract resonance history set"
     write (u, "(A)")
 
     call process%extract_resonance_history_set &
          (res_history_set(1), include_trivial=.true., i_component=1)
     call res_history_set(1)%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build resonant-subprocess library"
     write (u, "(A)")
 
     call prc_set%init (1)
     call prc_set%fill_resonances (res_history_set(1), 1)
 
     process_component_def => process%get_component_def_ptr (1)
     call prc_set%create_library (libname_res, global, exist)
     if (.not. exist) then
        call prc_set%add_to_library (1, &
             process_component_def%get_prt_spec_in (), &
             process_component_def%get_prt_spec_out (), &
             global)
     end if
     call prc_set%freeze_library (global)
     call prc_set%compile_library (global)
     call prc_set%write (u, testflag=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build particle set"
     write (u, "(A)")
 
     sqrts = global%get_rval (var_str ("sqrts"))
     mw = 80._default   ! deliberately slightly different from true mw
     pp = sqrt (sqrts**2 - 4 * mw**2) / 2
 
     allocate (pdg (5), p (5), m (5))
     pdg(1) = -11
     p(1) = vector4_moving (sqrts/2, sqrts/2, 3)
     m(1) = 0
     pdg(2) = 11
     p(2) = vector4_moving (sqrts/2,-sqrts/2, 3)
     m(2) = 0
     pdg(3) = 1
     p3(1) = pp/2
     p3(2) = mw/2
     p3(3) = 0
     p(3) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(3) = 0
     p3(2) = -mw/2
     pdg(4) = -2
     p(4) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(4) = 0
     pdg(5) = 24
     p(5) = vector4_moving (sqrts/2,-pp, 1)
     m(5) = mw
 
     call pset%init_direct (0, 2, 0, 0, 3, pdg, model)
     call pset%set_momentum (p, m**2)
     call pset%write (u, testflag=.true.)
 
      write (u, "(A)")
      write (u, "(A)")  "* Fill process instance"
 
     ! workflow from event_recalculate
     call process_instance%choose_mci (1)
     call process_instance%set_trace (pset, 1)
     call process_instance%recover &
          (1, 1, update_sqme=.true., recover_phs=.false.)
     call process_instance%evaluate_event_data (weight = 1._default)
 
     write (u, "(A)")
     write (u, "(A)")  "* Prepare resonant subprocesses"
 
     call prc_set%prepare_process_objects (global)
     call prc_set%prepare_process_instances (global)
 
     call evt_resonance%set_resonance_data (res_history_set)
     call evt_resonance%select_component (1)
     call prc_set%connect_transform (evt_resonance)
     call evt_resonance%connect (process_instance, model)
 
     call prc_set%fill_momenta ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Show squared matrix element of master process,"
     write (u, "(A)")  "  should coincide with 2nd subprocess sqme"
     write (u, "(A)")
 
     write (u, "(1x,I0,1x," // FMT_12 // ")")  0, prc_set%get_master_sqme ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Compute squared matrix elements &
          &of selected resonant subprocesses [1,2]"
     write (u, "(A)")
 
     call prc_set%evaluate_subprocess ([1,2])
 
     allocate (sqme (3), source = 0._default)
     call prc_set%get_subprocess_sqme (sqme)
     do i = 1, size (sqme)
        write (u, "(1x,I0,1x," // FMT_12 // ")")  i, sqme(i)
     end do
     deallocate (sqme)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compute squared matrix elements &
          &of all resonant subprocesses"
     write (u, "(A)")
 
     call prc_set%evaluate_subprocess ([1,2,3])
 
     allocate (sqme (3), source = 0._default)
     call prc_set%get_subprocess_sqme (sqme)
     do i = 1, size (sqme)
        write (u, "(1x,I0,1x," // FMT_12 // ")")  i, sqme(i)
     end do
     deallocate (sqme)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write process instances to file &
          &restricted_subprocesses_3_lib_res.dat"
 
     u_dump = free_unit ()
     open (unit = u_dump, file = "restricted_subprocesses_3_lib_res.dat", &
          action = "write", status = "replace")
     call prc_set%dump_instances (u_dump)
     close (u_dump)
 
     write (u, "(A)")
     write (u, "(A)")  "* Determine on-shell resonant subprocesses"
     write (u, "(A)")
 
     on_shell_limit = 0
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_limit =", on_shell_limit
     call prc_set%set_on_shell_limit (on_shell_limit)
     call prc_set%determine_on_shell_histories (1, i_array)
     write (u, "(1x,A,9(1x,I0))")  "resonant =", i_array
 
     on_shell_limit = 0.1_default
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_limit =", on_shell_limit
     call prc_set%set_on_shell_limit (on_shell_limit)
     call prc_set%determine_on_shell_histories (1, i_array)
     write (u, "(1x,A,9(1x,I0))")  "resonant =", i_array
 
     on_shell_limit = 10._default
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_limit =", on_shell_limit
     call prc_set%set_on_shell_limit (on_shell_limit)
     call prc_set%determine_on_shell_histories (1, i_array)
     write (u, "(1x,A,9(1x,I0))")  "resonant =", i_array
 
     on_shell_limit = 10000._default
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_limit =", on_shell_limit
     call prc_set%set_on_shell_limit (on_shell_limit)
     call prc_set%determine_on_shell_histories (1, i_array)
     write (u, "(1x,A,9(1x,I0))")  "resonant =", i_array
 
     write (u, "(A)")
     write (u, "(A)")  "* Compute probabilities for applicable resonances"
     write (u, "(A)")  "  and initialize the process selector"
     write (u, "(A)")  "  (The first number is the probability for background)"
     write (u, "(A)")
 
     on_shell_limit = 0
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_limit =", on_shell_limit
     call prc_set%set_on_shell_limit (on_shell_limit)
     call prc_set%determine_on_shell_histories (1, i_array)
     call prc_set%compute_probabilities (prob_array)
     write (u, "(1x,A,9(1x,"// FMT_12 // "))")  "resonant =", prob_array
     call prc_set%write (u, testflag=.true.)
     write (u, *)
 
     on_shell_limit = 10._default
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_limit =", on_shell_limit
     call prc_set%set_on_shell_limit (on_shell_limit)
     call prc_set%determine_on_shell_histories (1, i_array)
     call prc_set%compute_probabilities (prob_array)
     write (u, "(1x,A,9(1x,"// FMT_12 // "))")  "resonant =", prob_array
     call prc_set%write (u, testflag=.true.)
     write (u, *)
 
     on_shell_limit = 10000._default
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_limit =", on_shell_limit
     call prc_set%set_on_shell_limit (on_shell_limit)
     call prc_set%determine_on_shell_histories (1, i_array)
     call prc_set%compute_probabilities (prob_array)
     write (u, "(1x,A,9(1x,"// FMT_12 // "))")  "resonant =", prob_array
     write (u, *)
     call prc_set%write (u, testflag=.true.)
     write (u, *)
 
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_phs_forest_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: restricted_subprocesses_3"
 
   end subroutine restricted_subprocesses_3
 
 @ %def restricted_subprocesses_3
 @
 \subsubsection{Event transform}
 Prepare an actual process with resonant subprocesses.  Prepare the
 resonance selector for a fixed event and apply the resonance-insertion
 event transform.
 <<Restricted subprocesses: execute tests>>=
   call test (restricted_subprocesses_4, "restricted_subprocesses_4", &
        "event transform", &
        u, results)
 <<Restricted subprocesses: test declarations>>=
   public :: restricted_subprocesses_4
 <<Restricted subprocesses: tests>>=
   subroutine restricted_subprocesses_4 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     class(model_t), pointer :: model
     class(model_data_t), pointer :: model_data
     type(string_t) :: libname, libname_res
     type(string_t) :: procname
     type(process_component_def_t), pointer :: process_component_def
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     logical :: exist
     type(process_t), pointer :: process
     type(process_instance_t), target :: process_instance
     type(resonance_history_set_t), dimension(1) :: res_history_set
     type(resonant_subprocess_set_t) :: prc_set
     type(particle_set_t) :: pset
     real(default) :: sqrts, mw, pp
     real(default), dimension(3) :: p3
     type(vector4_t), dimension(:), allocatable :: p
     real(default), dimension(:), allocatable :: m
     integer, dimension(:), allocatable :: pdg
     real(default) :: on_shell_limit
     type(evt_trivial_t), target :: evt_trivial
     type(evt_resonance_t), target :: evt_resonance
     real(default) :: probability
     integer :: i
 
     write (u, "(A)")  "* Test output: restricted_subprocesses_4"
     write (u, "(A)")  "*   Purpose: employ event transform"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     call global%global_init ()
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%set_log (var_str ("?resonance_history"), &
          .true., is_known = .true.)
 
     call global%select_model (var_str ("SM"))
     allocate (model)
     call model%init_instance (global%model)
     model_data => model
 
     libname = "restricted_subprocesses_4_lib"
     libname_res = "restricted_subprocesses_4_lib_res"
     procname = "restricted_subprocesses_4_p"
 
     write (u, "(A)")  "* Initialize process library and process"
     write (u, "(A)")
 
     allocate (lib_entry)
     call lib_entry%init (libname)
     lib => lib_entry%process_library_t
     call global%add_prclib (lib_entry)
 
     call prepare_resonance_test_library &
          (lib, libname, procname, model_data, global, u)
 
     call integrate_process (procname, global, &
          local_stack = .true., init_only = .true.)
 
     process => global%process_stack%get_process_ptr (procname)
 
     call process_instance%init (process)
     call process_instance%setup_event_data ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Extract resonance history set"
 
     call process%extract_resonance_history_set &
          (res_history_set(1), include_trivial=.false., i_component=1)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build resonant-subprocess library"
 
     call prc_set%init (1)
     call prc_set%fill_resonances (res_history_set(1), 1)
 
     process_component_def => process%get_component_def_ptr (1)
     call prc_set%create_library (libname_res, global, exist)
     if (.not. exist) then
        call prc_set%add_to_library (1, &
             process_component_def%get_prt_spec_in (), &
             process_component_def%get_prt_spec_out (), &
             global)
     end if
     call prc_set%freeze_library (global)
     call prc_set%compile_library (global)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build particle set"
     write (u, "(A)")
 
     sqrts = global%get_rval (var_str ("sqrts"))
     mw = 80._default   ! deliberately slightly different from true mw
     pp = sqrt (sqrts**2 - 4 * mw**2) / 2
 
     allocate (pdg (5), p (5), m (5))
     pdg(1) = -11
     p(1) = vector4_moving (sqrts/2, sqrts/2, 3)
     m(1) = 0
     pdg(2) = 11
     p(2) = vector4_moving (sqrts/2,-sqrts/2, 3)
     m(2) = 0
     pdg(3) = 1
     p3(1) = pp/2
     p3(2) = mw/2
     p3(3) = 0
     p(3) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(3) = 0
     p3(2) = -mw/2
     pdg(4) = -2
     p(4) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(4) = 0
     pdg(5) = 24
     p(5) = vector4_moving (sqrts/2,-pp, 1)
     m(5) = mw
 
     call pset%init_direct (0, 2, 0, 0, 3, pdg, model)
     call pset%set_momentum (p, m**2)
 
     write (u, "(A)")  "* Fill process instance"
     write (u, "(A)")
 
     ! workflow from event_recalculate
     call process_instance%choose_mci (1)
     call process_instance%set_trace (pset, 1)
     call process_instance%recover &
          (1, 1, update_sqme=.true., recover_phs=.false.)
     call process_instance%evaluate_event_data (weight = 1._default)
 
     write (u, "(A)")  "* Prepare resonant subprocesses"
     write (u, "(A)")
 
     call prc_set%prepare_process_objects (global)
     call prc_set%prepare_process_instances (global)
 
     write (u, "(A)")  "* Fill trivial event transform (deliberately w/o color)"
     write (u, "(A)")
 
     call evt_trivial%connect (process_instance, model)
     call evt_trivial%set_particle_set (pset, 1, 1)
     call evt_trivial%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize resonance-insertion event transform"
     write (u, "(A)")
 
     evt_trivial%next => evt_resonance
     evt_resonance%previous => evt_trivial
 
     call evt_resonance%set_resonance_data (res_history_set)
     call evt_resonance%select_component (1)
     call evt_resonance%connect (process_instance, model)
     call prc_set%connect_transform (evt_resonance)
     call evt_resonance%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compute probabilities for applicable resonances"
     write (u, "(A)")  "  and initialize the process selector"
     write (u, "(A)")
 
     on_shell_limit = 10._default
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_limit =", on_shell_limit
     call evt_resonance%set_on_shell_limit (on_shell_limit)
 
     write (u, "(A)")
     write (u, "(A)")  "* Evaluate resonance-insertion event transform"
     write (u, "(A)")
 
     call evt_resonance%prepare_new_event (1, 1)
     call evt_resonance%generate_weighted (probability)
     call evt_resonance%make_particle_set (1, .false.)
 
     call evt_resonance%write (u, testflag=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_phs_forest_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: restricted_subprocesses_4"
 
   end subroutine restricted_subprocesses_4
 
 @ %def restricted_subprocesses_4
 @
 \subsubsection{Gaussian turnoff}
 Identical to the previous process, except that we apply a Gaussian
 turnoff to the resonance kinematics, which affects the subprocess selector.
 <<Restricted subprocesses: execute tests>>=
   call test (restricted_subprocesses_5, "restricted_subprocesses_5", &
        "event transform with gaussian turnoff", &
        u, results)
 <<Restricted subprocesses: test declarations>>=
   public :: restricted_subprocesses_5
 <<Restricted subprocesses: tests>>=
   subroutine restricted_subprocesses_5 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     class(model_t), pointer :: model
     class(model_data_t), pointer :: model_data
     type(string_t) :: libname, libname_res
     type(string_t) :: procname
     type(process_component_def_t), pointer :: process_component_def
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     logical :: exist
     type(process_t), pointer :: process
     type(process_instance_t), target :: process_instance
     type(resonance_history_set_t), dimension(1) :: res_history_set
     type(resonant_subprocess_set_t) :: prc_set
     type(particle_set_t) :: pset
     real(default) :: sqrts, mw, pp
     real(default), dimension(3) :: p3
     type(vector4_t), dimension(:), allocatable :: p
     real(default), dimension(:), allocatable :: m
     integer, dimension(:), allocatable :: pdg
     real(default) :: on_shell_limit
     real(default) :: on_shell_turnoff
     type(evt_trivial_t), target :: evt_trivial
     type(evt_resonance_t), target :: evt_resonance
     real(default) :: probability
     integer :: i
 
     write (u, "(A)")  "* Test output: restricted_subprocesses_5"
     write (u, "(A)")  "*   Purpose: employ event transform &
          &with gaussian turnoff"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     call global%global_init ()
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%set_log (var_str ("?resonance_history"), &
          .true., is_known = .true.)
 
     call global%select_model (var_str ("SM"))
     allocate (model)
     call model%init_instance (global%model)
     model_data => model
 
     libname = "restricted_subprocesses_5_lib"
     libname_res = "restricted_subprocesses_5_lib_res"
     procname = "restricted_subprocesses_5_p"
 
     write (u, "(A)")  "* Initialize process library and process"
     write (u, "(A)")
 
     allocate (lib_entry)
     call lib_entry%init (libname)
     lib => lib_entry%process_library_t
     call global%add_prclib (lib_entry)
 
     call prepare_resonance_test_library &
          (lib, libname, procname, model_data, global, u)
 
     call integrate_process (procname, global, &
          local_stack = .true., init_only = .true.)
 
     process => global%process_stack%get_process_ptr (procname)
 
     call process_instance%init (process)
     call process_instance%setup_event_data ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Extract resonance history set"
 
     call process%extract_resonance_history_set &
          (res_history_set(1), include_trivial=.false., i_component=1)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build resonant-subprocess library"
 
     call prc_set%init (1)
     call prc_set%fill_resonances (res_history_set(1), 1)
 
     process_component_def => process%get_component_def_ptr (1)
     call prc_set%create_library (libname_res, global, exist)
     if (.not. exist) then
        call prc_set%add_to_library (1, &
             process_component_def%get_prt_spec_in (), &
             process_component_def%get_prt_spec_out (), &
             global)
     end if
     call prc_set%freeze_library (global)
     call prc_set%compile_library (global)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build particle set"
     write (u, "(A)")
 
     sqrts = global%get_rval (var_str ("sqrts"))
     mw = 80._default   ! deliberately slightly different from true mw
     pp = sqrt (sqrts**2 - 4 * mw**2) / 2
 
     allocate (pdg (5), p (5), m (5))
     pdg(1) = -11
     p(1) = vector4_moving (sqrts/2, sqrts/2, 3)
     m(1) = 0
     pdg(2) = 11
     p(2) = vector4_moving (sqrts/2,-sqrts/2, 3)
     m(2) = 0
     pdg(3) = 1
     p3(1) = pp/2
     p3(2) = mw/2
     p3(3) = 0
     p(3) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(3) = 0
     p3(2) = -mw/2
     pdg(4) = -2
     p(4) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(4) = 0
     pdg(5) = 24
     p(5) = vector4_moving (sqrts/2,-pp, 1)
     m(5) = mw
 
     call pset%init_direct (0, 2, 0, 0, 3, pdg, model)
     call pset%set_momentum (p, m**2)
 
     write (u, "(A)")  "* Fill process instance"
     write (u, "(A)")
 
     ! workflow from event_recalculate
     call process_instance%choose_mci (1)
     call process_instance%set_trace (pset, 1)
     call process_instance%recover &
          (1, 1, update_sqme=.true., recover_phs=.false.)
     call process_instance%evaluate_event_data (weight = 1._default)
 
     write (u, "(A)")  "* Prepare resonant subprocesses"
     write (u, "(A)")
 
     call prc_set%prepare_process_objects (global)
     call prc_set%prepare_process_instances (global)
 
     write (u, "(A)")  "* Fill trivial event transform (deliberately w/o color)"
     write (u, "(A)")
 
     call evt_trivial%connect (process_instance, model)
     call evt_trivial%set_particle_set (pset, 1, 1)
     call evt_trivial%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize resonance-insertion event transform"
     write (u, "(A)")
 
     evt_trivial%next => evt_resonance
     evt_resonance%previous => evt_trivial
 
     call evt_resonance%set_resonance_data (res_history_set)
     call evt_resonance%select_component (1)
     call evt_resonance%connect (process_instance, model)
     call prc_set%connect_transform (evt_resonance)
     call evt_resonance%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compute probabilities for applicable resonances"
     write (u, "(A)")  "  and initialize the process selector"
     write (u, "(A)")
 
     on_shell_limit = 10._default
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_limit   =", &
          on_shell_limit
     call evt_resonance%set_on_shell_limit (on_shell_limit)
 
     on_shell_turnoff = 1._default
     write (u, "(1x,A,1x," // FMT_10 // ")")  "on_shell_turnoff =", &
          on_shell_turnoff
     call evt_resonance%set_on_shell_turnoff (on_shell_turnoff)
 
     write (u, "(A)")
     write (u, "(A)")  "* Evaluate resonance-insertion event transform"
     write (u, "(A)")
 
     call evt_resonance%prepare_new_event (1, 1)
     call evt_resonance%generate_weighted (probability)
     call evt_resonance%make_particle_set (1, .false.)
 
     call evt_resonance%write (u, testflag=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_phs_forest_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: restricted_subprocesses_5"
 
   end subroutine restricted_subprocesses_5
 
 @ %def restricted_subprocesses_5
 @
 \subsubsection{Event transform}
 The same process and event again.  This time, switch off the background
 contribution, so the selector becomes trivial.
 <<Restricted subprocesses: execute tests>>=
   call test (restricted_subprocesses_6, "restricted_subprocesses_6", &
        "event transform with background switched off", &
        u, results)
 <<Restricted subprocesses: test declarations>>=
   public :: restricted_subprocesses_6
 <<Restricted subprocesses: tests>>=
   subroutine restricted_subprocesses_6 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     class(model_t), pointer :: model
     class(model_data_t), pointer :: model_data
     type(string_t) :: libname, libname_res
     type(string_t) :: procname
     type(process_component_def_t), pointer :: process_component_def
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     logical :: exist
     type(process_t), pointer :: process
     type(process_instance_t), target :: process_instance
     type(resonance_history_set_t), dimension(1) :: res_history_set
     type(resonant_subprocess_set_t) :: prc_set
     type(particle_set_t) :: pset
     real(default) :: sqrts, mw, pp
     real(default), dimension(3) :: p3
     type(vector4_t), dimension(:), allocatable :: p
     real(default), dimension(:), allocatable :: m
     integer, dimension(:), allocatable :: pdg
     real(default) :: on_shell_limit
     real(default) :: background_factor
     type(evt_trivial_t), target :: evt_trivial
     type(evt_resonance_t), target :: evt_resonance
     real(default) :: probability
     integer :: i
 
     write (u, "(A)")  "* Test output: restricted_subprocesses_6"
     write (u, "(A)")  "*   Purpose: employ event transform &
          &with background switched off"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     call global%global_init ()
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%set_log (var_str ("?resonance_history"), &
          .true., is_known = .true.)
 
     call global%select_model (var_str ("SM"))
     allocate (model)
     call model%init_instance (global%model)
     model_data => model
 
     libname = "restricted_subprocesses_6_lib"
     libname_res = "restricted_subprocesses_6_lib_res"
     procname = "restricted_subprocesses_6_p"
 
     write (u, "(A)")  "* Initialize process library and process"
     write (u, "(A)")
 
     allocate (lib_entry)
     call lib_entry%init (libname)
     lib => lib_entry%process_library_t
     call global%add_prclib (lib_entry)
 
     call prepare_resonance_test_library &
          (lib, libname, procname, model_data, global, u)
 
     call integrate_process (procname, global, &
          local_stack = .true., init_only = .true.)
 
     process => global%process_stack%get_process_ptr (procname)
 
     call process_instance%init (process)
     call process_instance%setup_event_data ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Extract resonance history set"
 
     call process%extract_resonance_history_set &
          (res_history_set(1), include_trivial=.false., i_component=1)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build resonant-subprocess library"
 
     call prc_set%init (1)
     call prc_set%fill_resonances (res_history_set(1), 1)
 
     process_component_def => process%get_component_def_ptr (1)
     call prc_set%create_library (libname_res, global, exist)
     if (.not. exist) then
        call prc_set%add_to_library (1, &
             process_component_def%get_prt_spec_in (), &
             process_component_def%get_prt_spec_out (), &
             global)
     end if
     call prc_set%freeze_library (global)
     call prc_set%compile_library (global)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build particle set"
     write (u, "(A)")
 
     sqrts = global%get_rval (var_str ("sqrts"))
     mw = 80._default   ! deliberately slightly different from true mw
     pp = sqrt (sqrts**2 - 4 * mw**2) / 2
 
     allocate (pdg (5), p (5), m (5))
     pdg(1) = -11
     p(1) = vector4_moving (sqrts/2, sqrts/2, 3)
     m(1) = 0
     pdg(2) = 11
     p(2) = vector4_moving (sqrts/2,-sqrts/2, 3)
     m(2) = 0
     pdg(3) = 1
     p3(1) = pp/2
     p3(2) = mw/2
     p3(3) = 0
     p(3) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(3) = 0
     p3(2) = -mw/2
     pdg(4) = -2
     p(4) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(4) = 0
     pdg(5) = 24
     p(5) = vector4_moving (sqrts/2,-pp, 1)
     m(5) = mw
 
     call pset%init_direct (0, 2, 0, 0, 3, pdg, model)
     call pset%set_momentum (p, m**2)
 
     write (u, "(A)")  "* Fill process instance"
     write (u, "(A)")
 
     ! workflow from event_recalculate
     call process_instance%choose_mci (1)
     call process_instance%set_trace (pset, 1)
     call process_instance%recover &
          (1, 1, update_sqme=.true., recover_phs=.false.)
     call process_instance%evaluate_event_data (weight = 1._default)
 
     write (u, "(A)")  "* Prepare resonant subprocesses"
     write (u, "(A)")
 
     call prc_set%prepare_process_objects (global)
     call prc_set%prepare_process_instances (global)
 
     write (u, "(A)")  "* Fill trivial event transform (deliberately w/o color)"
     write (u, "(A)")
 
     call evt_trivial%connect (process_instance, model)
     call evt_trivial%set_particle_set (pset, 1, 1)
     call evt_trivial%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize resonance-insertion event transform"
     write (u, "(A)")
 
     evt_trivial%next => evt_resonance
     evt_resonance%previous => evt_trivial
 
     call evt_resonance%set_resonance_data (res_history_set)
     call evt_resonance%select_component (1)
     call evt_resonance%connect (process_instance, model)
     call prc_set%connect_transform (evt_resonance)
     call evt_resonance%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compute probabilities for applicable resonances"
     write (u, "(A)")  "  and initialize the process selector"
     write (u, "(A)")
 
     on_shell_limit = 10._default
     write (u, "(1x,A,1x," // FMT_10 // ")") &
          "on_shell_limit    =", on_shell_limit
     call evt_resonance%set_on_shell_limit (on_shell_limit)
 
     background_factor = 0
     write (u, "(1x,A,1x," // FMT_10 // ")") &
          "background_factor =", background_factor
     call evt_resonance%set_background_factor (background_factor)
 
     write (u, "(A)")
     write (u, "(A)")  "* Evaluate resonance-insertion event transform"
     write (u, "(A)")
 
     call evt_resonance%prepare_new_event (1, 1)
     call evt_resonance%generate_weighted (probability)
     call evt_resonance%make_particle_set (1, .false.)
 
     call evt_resonance%write (u, testflag=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
     call syntax_phs_forest_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: restricted_subprocesses_6"
 
   end subroutine restricted_subprocesses_6
 
 @ %def restricted_subprocesses_6
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Simulation}
 This module manages simulation: event generation and reading/writing of event
 files.  The [[simulation]] object is intended to be used (via a pointer)
 outside of \whizard, if events are generated individually by an external
 driver.
 <<[[simulations.f90]]>>=
 <<File header>>
 
 module simulations
 
 <<Use kinds>>
 <<Use strings>>
 <<Use debug>>
   use io_units
   use format_utils, only: write_separator
   use format_defs, only: FMT_15, FMT_19
   use os_interface
   use numeric_utils
   use string_utils, only: str
   use diagnostics
   use lorentz, only: vector4_t
   use sm_qcd
   use md5
   use variables, only: var_list_t
   use eval_trees
   use model_data
   use flavors
   use particles
   use state_matrices, only: FM_IGNORE_HELICITY
   use beam_structures, only: beam_structure_t
   use beams
   use rng_base
   use rng_stream, only: rng_stream_t
   use selectors
   use resonances, only: resonance_history_set_t
   use process_libraries, only: process_library_t
   use process_libraries, only: process_component_def_t
   use prc_core
   !  TODO: (bcn 2016-09-13) should be ideally only pcm_base
   use pcm, only: pcm_nlo_t, pcm_instance_nlo_t
   !  TODO: (bcn 2016-09-13) details of process config should not be necessary here
   use process_config, only: COMP_REAL_FIN
   use process
   use instances
   use event_base
   use events
   use event_transforms
   use shower
   use eio_data
   use eio_base
   use rt_data
 
   use dispatch_beams, only: dispatch_qcd
   use dispatch_rng, only: dispatch_rng_factory
   use dispatch_rng, only: update_rng_seed_in_var_list
   use dispatch_me_methods, only: dispatch_core_update, dispatch_core_restore
   use dispatch_transforms, only: dispatch_evt_isr_epa_handler
   use dispatch_transforms, only: dispatch_evt_resonance
   use dispatch_transforms, only: dispatch_evt_decay
   use dispatch_transforms, only: dispatch_evt_shower
   use dispatch_transforms, only: dispatch_evt_hadrons
   use dispatch_transforms, only: dispatch_evt_nlo
 
   use integrations
   use event_streams
   use restricted_subprocesses, only: resonant_subprocess_set_t
   use restricted_subprocesses, only: get_libname_res
 
   use evt_nlo
 
 <<Use mpi f08>>
 
 <<Standard module head>>
 
 <<Simulations: public>>
 
 <<Simulations: types>>
 
 <<Simulations: interfaces>>
 
 contains
 
 <<Simulations: procedures>>
 
 end module simulations
 @ %def simulations
 @
 \subsection{Event counting}
 In this object we collect statistical information about an event
 sample or sub-sample.
 <<Simulations: types>>=
   type :: counter_t
      integer :: total = 0
      integer :: generated = 0
      integer :: read = 0
      integer :: positive = 0
      integer :: negative = 0
      integer :: zero = 0
      integer :: excess = 0
      integer :: dropped = 0
      real(default) :: max_excess = 0
      real(default) :: sum_excess = 0
      logical :: reproduce_xsection = .false.
      real(default) :: mean = 0
      real(default) :: varsq = 0
      integer :: nlo_weight_counter = 0
    contains
    <<Simulations: counter: TBP>>
   end type counter_t
 
 @ %def simulation_counter_t
 @ Output.
 <<Simulations: counter: TBP>>=
   procedure :: write => counter_write
 <<Simulations: procedures>>=
   subroutine counter_write (counter, unit)
     class(counter_t), intent(in) :: counter
     integer, intent(in), optional :: unit
     integer :: u
     u = given_output_unit (unit)
 1   format (3x,A,I0)
 2   format (5x,A,I0)
 3   format (5x,A,ES19.12)
     write (u, 1)  "Events total      = ", counter%total
     write (u, 2)  "generated       = ", counter%generated
     write (u, 2)  "read            = ", counter%read
     write (u, 2)  "positive weight = ", counter%positive
     write (u, 2)  "negative weight = ", counter%negative
     write (u, 2)  "zero weight     = ", counter%zero
     write (u, 2)  "excess weight   = ", counter%excess
     if (counter%excess /= 0) then
        write (u, 3)  "max excess      = ", counter%max_excess
        write (u, 3)  "avg excess      = ", counter%sum_excess / counter%total
     end if
     write (u, 1)  "Events dropped    = ", counter%dropped
   end subroutine counter_write
 
 @ %def counter_write
 @ This is a screen message: if there was an excess, display statistics.
 <<Simulations: counter: TBP>>=
   procedure :: show_excess => counter_show_excess
 <<Simulations: procedures>>=
   subroutine counter_show_excess (counter)
     class(counter_t), intent(in) :: counter
     if (counter%excess > 0) then
        write (msg_buffer, "(A,1x,I0,1x,A,1x,'(',F7.3,' %)')") &
             "Encountered events with excess weight:", counter%excess, &
             "events", 100 * counter%excess / real (counter%total)
        call msg_warning ()
        write (msg_buffer, "(A,ES10.3)") &
             "Maximum excess weight =", counter%max_excess
        call msg_message ()
        write (msg_buffer, "(A,ES10.3)") &
             "Average excess weight =", counter%sum_excess / counter%total
        call msg_message ()
     end if
   end subroutine counter_show_excess
 
 @ %def counter_show_excess
 @ If events have been dropped during simulation of weighted events,
 issue a message here.
 <<Simulations: counter: TBP>>=
   procedure :: show_dropped => counter_show_dropped
 <<Simulations: procedures>>=
   subroutine counter_show_dropped (counter)
     class(counter_t), intent(in) :: counter
     if (counter%dropped > 0) then
        write (msg_buffer, "(A,1x,I0,1x,'(',A,1x,I0,')')") &
             "Dropped events (weight zero) =", &
             counter%dropped, "total", counter%dropped + counter%total
        call msg_message ()
        write (msg_buffer, "(A,ES15.8)") &
             "All event weights must be rescaled by f =", &
             real (counter%total, default) &
             / real (counter%dropped + counter%total, default)
        call msg_warning ()
     end if
   end subroutine counter_show_dropped
   
 @ %def counter_show_dropped
 @
 <<Simulations: counter: TBP>>=
   procedure :: show_mean_and_variance => counter_show_mean_and_variance
 <<Simulations: procedures>>=
   subroutine counter_show_mean_and_variance (counter)
     class(counter_t), intent(in) :: counter
     if (counter%reproduce_xsection .and. counter%nlo_weight_counter > 1) then
        print *,  "Reconstructed cross-section from event weights: "
        print *,  counter%mean, '+-', sqrt (counter%varsq / (counter%nlo_weight_counter - 1))
     end if
   end subroutine counter_show_mean_and_variance
 
 @ %def counter_show_mean_and_variance
 @ Count an event.  The weight and event source are optional; by
 default we assume that the event has been generated and has positive
 weight.
 
 The optional integer [[n_dropped]] counts weighted events with weight
 zero that were encountered while generating the current event, but
 dropped (because of their zero weight).  Accumulating this number
 allows for renormalizing event weight sums in histograms, after the
 generation step has been completed.
 <<Simulations: counter: TBP>>=
   procedure :: record => counter_record
 <<Simulations: procedures>>=
   subroutine counter_record (counter, weight, excess, n_dropped, from_file)
     class(counter_t), intent(inout) :: counter
     real(default), intent(in), optional :: weight, excess
     integer, intent(in), optional :: n_dropped
     logical, intent(in), optional :: from_file
     counter%total = counter%total + 1
     if (present (from_file)) then
        if (from_file) then
           counter%read = counter%read + 1
        else
           counter%generated = counter%generated + 1
        end if
     else
        counter%generated = counter%generated + 1
     end if
     if (present (weight)) then
        if (weight > 0) then
           counter%positive = counter%positive + 1
        else if (weight < 0) then
           counter%negative = counter%negative + 1
        else
           counter%zero = counter%zero + 1
        end if
     else
        counter%positive = counter%positive + 1
     end if
     if (present (excess)) then
        if (excess > 0) then
           counter%excess = counter%excess + 1
           counter%max_excess = max (counter%max_excess, excess)
           counter%sum_excess = counter%sum_excess + excess
        end if
     end if
     if (present (n_dropped)) then
        counter%dropped = counter%dropped + n_dropped
     end if
   end subroutine counter_record
 
 @ %def counter_record
 @
 <<Simulations: counter: TBP>>=
   procedure :: record_mean_and_variance => &
      counter_record_mean_and_variance
 <<Simulations: procedures>>=
   subroutine counter_record_mean_and_variance (counter, weight, i_nlo)
     class(counter_t), intent(inout) :: counter
     real(default), intent(in) :: weight
     integer, intent(in) :: i_nlo
     real(default), save :: weight_buffer = 0._default
     integer, save :: nlo_count = 1
     if (.not. counter%reproduce_xsection) return
     if (i_nlo == 1) then
        call flush_weight_buffer (weight_buffer, nlo_count)
        weight_buffer = weight
        nlo_count = 1
     else
        weight_buffer = weight_buffer + weight
        nlo_count = nlo_count + 1
     end if
   contains
     subroutine flush_weight_buffer (w, n_nlo)
       real(default), intent(in) :: w
       integer, intent(in) :: n_nlo
       integer :: n
       real(default) :: mean_new
       counter%nlo_weight_counter = counter%nlo_weight_counter + 1
       !!! Minus 1 to take into account offset from initialization
       n = counter%nlo_weight_counter - 1
       if (n > 0) then
          mean_new = counter%mean + (w / n_nlo - counter%mean) / n
          if (n > 1) &
             counter%varsq = counter%varsq - counter%varsq / (n - 1) + &
                n * (mean_new - counter%mean)**2
          counter%mean = mean_new
       end if
     end subroutine flush_weight_buffer
   end subroutine counter_record_mean_and_variance
 
 @ %def counter_record_mean_and_variance
 @
 \subsection{Simulation: component sets}
 For each set of process components that share a MCI entry in the
 process configuration, we keep a separate event record.
 <<Simulations: types>>=
   type :: mci_set_t
      private
      integer :: n_components = 0
      integer, dimension(:), allocatable :: i_component
      type(string_t), dimension(:), allocatable :: component_id
      logical :: has_integral = .false.
      real(default) :: integral = 0
      real(default) :: error = 0
      real(default) :: weight_mci = 0
      type(counter_t) :: counter
    contains
    <<Simulations: mci set: TBP>>
   end type mci_set_t
 
 @ %def mci_set_t
 @ Output.
 <<Simulations: mci set: TBP>>=
   procedure :: write => mci_set_write
 <<Simulations: procedures>>=
   subroutine mci_set_write (object, unit, pacified)
     class(mci_set_t), intent(in) :: object
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: pacified
     logical :: pacify
     integer :: u, i
     u = given_output_unit (unit)
     pacify = .false.;  if (present (pacified))  pacify = pacified
     write (u, "(3x,A)")  "Components:"
     do i = 1, object%n_components
        write (u, "(5x,I0,A,A,A)")  object%i_component(i), &
             ": '", char (object%component_id(i)), "'"
     end do
     if (object%has_integral) then
        if (pacify) then
           write (u, "(3x,A," // FMT_15 // ")")  "Integral  = ", object%integral
           write (u, "(3x,A," // FMT_15 // ")")  "Error     = ", object%error
           write (u, "(3x,A,F9.6)")  "Weight    =", object%weight_mci
        else
           write (u, "(3x,A," // FMT_19 // ")")  "Integral  = ", object%integral
           write (u, "(3x,A," // FMT_19 // ")")  "Error     = ", object%error
           write (u, "(3x,A,F13.10)")  "Weight    =", object%weight_mci
        end if
     else
        write (u, "(3x,A)")  "Integral  = [undefined]"
     end if
     call object%counter%write (u)
   end subroutine mci_set_write
 
 @ %def mci_set_write
 @ Initialize: Get the indices and names for the process components
 that will contribute to this set.
 <<Simulations: mci set: TBP>>=
   procedure :: init => mci_set_init
 <<Simulations: procedures>>=
   subroutine mci_set_init (object, i_mci, process)
     class(mci_set_t), intent(out) :: object
     integer, intent(in) :: i_mci
     type(process_t), intent(in), target :: process
     integer :: i
     call process%get_i_component (i_mci, object%i_component)
     object%n_components = size (object%i_component)
     allocate (object%component_id (object%n_components))
     do i = 1, size (object%component_id)
        object%component_id(i) = &
             process%get_component_id (object%i_component(i))
     end do
     if (process%has_integral (i_mci)) then
        object%integral = process%get_integral (i_mci)
        object%error = process%get_error (i_mci)
        object%has_integral = .true.
     end if
   end subroutine mci_set_init
 
 @ %def mci_set_init
 @
 \subsection{Process-core Safe}
 This is an object that temporarily holds a process core object.  We
 need this while rescanning a process with modified parameters.  After
 the rescan, we want to restore the original state.
 <<Simulations: types>>=
   type :: core_safe_t
      class(prc_core_t), allocatable :: core
   end type core_safe_t
 
 @ %def core_safe_t
 @
 \subsection{Process Object}
 The simulation works on process objects.  This subroutine makes a
 process object available for simulation.  The process is in the
 process stack.  [[use_process]] implies that the process should
 already exist as an object in the process stack.  If integration is
 not yet done, do it.  Any generated process object should be put on
 the global stack, if it is separate from the local one.
 <<Simulations: procedures>>=
   subroutine prepare_process &
        (process, process_id, use_process, integrate, local, global)
     type(process_t), pointer, intent(out) :: process
     type(string_t), intent(in) :: process_id
     logical, intent(in) :: use_process, integrate
     type(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(inout), optional, target :: global
     type(rt_data_t), pointer :: current
     if (debug_on) call msg_debug (D_CORE, "prepare_process")
     if (debug_on) call msg_debug (D_CORE, "global present", present (global))
     if (present (global)) then
        current => global
     else
        current => local
     end if
     process => current%process_stack%get_process_ptr (process_id)
     if (debug_on) call msg_debug (D_CORE, "use_process", use_process)
     if (debug_on) call msg_debug (D_CORE, "associated process", associated (process))
     if (use_process .and. .not. associated (process)) then
        if (integrate) then
           call msg_message ("Simulate: process '" &
                // char (process_id) // "' needs integration")
        else
           call msg_message ("Simulate: process '" &
                // char (process_id) // "' needs initialization")
        end if
        if (present (global)) then
           call integrate_process (process_id, local, global, &
             init_only = .not. integrate)
        else
           call integrate_process (process_id, local, &
                local_stack = .true., init_only = .not. integrate)
        end if
        if (signal_is_pending ())  return
        process => current%process_stack%get_process_ptr (process_id)
        if (associated (process)) then
           if (integrate) then
              call msg_message ("Simulate: integration done")
              call current%process_stack%fill_result_vars (process_id)
           else
              call msg_message ("Simulate: process initialization done")
           end if
        else
           call msg_fatal ("Simulate: process '" &
                // char (process_id) // "' could not be initialized: aborting")
        end if
     else if (.not. associated (process)) then
        if (present (global)) then
           call integrate_process (process_id, local, global, &
                init_only = .true.)
        else
           call integrate_process (process_id, local, &
                local_stack = .true., init_only = .true.)
        end if
        process => current%process_stack%get_process_ptr (process_id)
        call msg_message &
             ("Simulate: process '" &
                // char (process_id) // "': enabled for rescan only")
     end if
   end subroutine prepare_process
 
 @ %def prepare_process
 @
 \subsection{Simulation entry}
 For each process that we consider for event generation, we need a
 separate entry.  The entry separately records the process ID and run ID.  The
 [[weight_mci]] array is used for selecting a component set (which
 shares a MCI record inside the process container) when generating an
 event for the current process.
 
 The simulation entry is an extension of the [[event_t]] event record.
 This core object contains configuration data, pointers to the process
 and process instance, the expressions, flags and values that are
 evaluated at runtime, and the resulting particle set.
 
 The entry explicitly allocate the [[process_instance]], which becomes
 the process-specific workspace for the event record.
 
 If entries with differing environments are present simultaneously, we
 may need to switch QCD parameters and/or the model event by event.  In
 this case, the [[qcd]] and/or [[model]] components are present.\\
 For the puropose of NLO events, [[entry_t]] contains a pointer list
 to other simulation-entries. This is due to the fact that we have to
 associate an event for each component of the fixed order simulation,
 i.e. one $N$-particle event and $N_\alpha$ $N+1$-particle events.
 However, all entries share the same event transforms.
 <<Simulations: types>>=
   type, extends (event_t) :: entry_t
      private
      type(string_t) :: process_id
      type(string_t) :: library
      type(string_t) :: run_id
      logical :: has_integral = .false.
      real(default) :: integral = 0
      real(default) :: error = 0
      real(default) :: process_weight = 0
      logical :: valid = .false.
      type(counter_t) :: counter
      integer :: n_in = 0
      integer :: n_mci = 0
      type(mci_set_t), dimension(:), allocatable :: mci_sets
      type(selector_t) :: mci_selector
      logical :: has_resonant_subprocess_set = .false.
      type(resonant_subprocess_set_t) :: resonant_subprocess_set
      type(core_safe_t), dimension(:), allocatable :: core_safe
      class(model_data_t), pointer :: model => null ()
      type(qcd_t) :: qcd
      type(entry_t), pointer :: first => null ()
      type(entry_t), pointer :: next => null ()
      class(evt_t), pointer :: evt_powheg => null ()
    contains
    <<Simulations: entry: TBP>>
   end type entry_t
 
 @ %def entry_t
 @ Output.  Write just the configuration, the event is written by a
 separate routine.
 
 The [[verbose]] option is unused, it is required by the interface of
 the base-object method.
 <<Simulations: entry: TBP>>=
   procedure :: write_config => entry_write_config
 <<Simulations: procedures>>=
   subroutine entry_write_config (object, unit, pacified)
     class(entry_t), intent(in) :: object
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: pacified
     logical :: pacify
     integer :: u, i
     u = given_output_unit (unit)
     pacify = .false.;  if (present (pacified))  pacify = pacified
     write (u, "(3x,A,A,A)")  "Process   = '", char (object%process_id), "'"
     write (u, "(3x,A,A,A)")  "Library   = '", char (object%library), "'"
     write (u, "(3x,A,A,A)")  "Run       = '", char (object%run_id), "'"
     write (u, "(3x,A,L1)")   "is valid  = ", object%valid
     if (object%has_integral) then
        if (pacify) then
           write (u, "(3x,A," // FMT_15 // ")")  "Integral  = ", object%integral
           write (u, "(3x,A," // FMT_15 // ")")  "Error     = ", object%error
           write (u, "(3x,A,F9.6)")  "Weight    =", object%process_weight
        else
           write (u, "(3x,A," // FMT_19 // ")")  "Integral  = ", object%integral
           write (u, "(3x,A," // FMT_19 // ")")  "Error     = ", object%error
           write (u, "(3x,A,F13.10)")  "Weight    =", object%process_weight
        end if
     else
        write (u, "(3x,A)")  "Integral  = [undefined]"
     end if
     write (u, "(3x,A,I0)")   "MCI sets  = ", object%n_mci
     call object%counter%write (u)
     do i = 1, size (object%mci_sets)
        write (u, "(A)")
        write (u, "(1x,A,I0,A)")  "MCI set #", i, ":"
        call object%mci_sets(i)%write (u, pacified)
     end do
     if (object%resonant_subprocess_set%is_active ()) then
        write (u, "(A)")
        call object%write_resonant_subprocess_data (u)
     end if
     if (allocated (object%core_safe)) then
        do i = 1, size (object%core_safe)
           write (u, "(1x,A,I0,A)")  "Saved process-component core #", i, ":"
           call object%core_safe(i)%core%write (u)
        end do
     end if
   end subroutine entry_write_config
 
 @ %def entry_write_config
 @ Finalizer.  The [[instance]] pointer component of the [[event_t]]
 base type points to a target which we did explicitly allocate in the
 [[entry_init]] procedure.  Therefore, we finalize and explicitly
 deallocate it here.  Then we call the finalizer of the base type.
 <<Simulations: entry: TBP>>=
   procedure :: final => entry_final
 <<Simulations: procedures>>=
   subroutine entry_final (object)
     class(entry_t), intent(inout) :: object
     integer :: i
     if (associated (object%instance)) then
        do i = 1, object%n_mci
           call object%instance%final_simulation (i)
        end do
        call object%instance%final ()
        deallocate (object%instance)
     end if
     call object%event_t%final ()
   end subroutine entry_final
 
 @ %def entry_final
 @ Copy the content of an entry into another one, except for the next-pointer
 <<Simulations: entry: TBP>>=
   procedure :: copy_entry => entry_copy_entry
 <<Simulations: procedures>>=
   subroutine entry_copy_entry (entry1, entry2)
     class(entry_t), intent(in), target :: entry1
     type(entry_t), intent(inout), target :: entry2
     call entry1%event_t%clone (entry2%event_t)
     entry2%process_id = entry1%process_id
     entry2%library = entry1%library
     entry2%run_id = entry1%run_id
     entry2%has_integral = entry1%has_integral
     entry2%integral = entry1%integral
     entry2%error = entry1%error
     entry2%process_weight = entry1%process_weight
     entry2%valid = entry1%valid
     entry2%counter = entry1%counter
     entry2%n_in = entry1%n_in
     entry2%n_mci = entry1%n_mci
     if (allocated (entry1%mci_sets)) then
        allocate (entry2%mci_sets (size (entry1%mci_sets)))
        entry2%mci_sets = entry1%mci_sets
     end if
     entry2%mci_selector = entry1%mci_selector
     if (allocated (entry1%core_safe)) then
        allocate (entry2%core_safe (size (entry1%core_safe)))
        entry2%core_safe = entry1%core_safe
     end if
     entry2%model => entry1%model
     entry2%qcd = entry1%qcd
   end subroutine entry_copy_entry
 
 @ %def entry_copy_entry
 @ Initialization.  Search for a process entry and allocate a process
 instance as an anonymous object, temporarily accessible via the
 [[process_instance]] pointer.  Assign data by looking at the process
 object and at the environment.
 
 If [[n_alt]] is set, we prepare for additional alternate sqme and weight
 entries.
 
 The [[compile]] flag is only false if we don't need the Whizard
 process at all, just its definition.  In that case, we skip process
 initialization.
 
 Otherwise, and if the process object is not found initially: if
 [[integrate]] is set, attempt an integration pass and try again.
 Otherwise, just initialize the object.
 
 If [[generate]] is set, prepare the MCI objects for generating new events.
 For pure rescanning, this is not necessary.
 
 If [[resonance_history]] is set, we create a separate process library
 which contains all possible restricted subprocesses with distinct
 resonance histories.  These processes will not be integrated, but
 their matrix element codes are used for determining probabilities of
 resonance histories.  Note that this can work only if the process
 method is OMega, and the phase-space method is 'wood'.
 
 When done, we assign the [[instance]] and [[process]] pointers of the
 base type by the [[connect]] method, so we can reference them later.
 
 TODO: In case of NLO event generation, copying the configuration from the
 master process is rather intransparent.  For instance, we override the process
 var list by the global var list.
 <<Simulations: entry: TBP>>=
   procedure :: init => entry_init
 <<Simulations: procedures>>=
   subroutine entry_init &
        (entry, process_id, &
        use_process, integrate, generate, update_sqme, &
        support_resonance_history, &
        local, global, n_alt)
     class(entry_t), intent(inout), target :: entry
     type(string_t), intent(in) :: process_id
     logical, intent(in) :: use_process, integrate, generate, update_sqme
     logical, intent(in) :: support_resonance_history
     type(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(inout), optional, target :: global
     integer, intent(in), optional :: n_alt
     type(process_t), pointer :: process, master_process
     type(process_instance_t), pointer :: process_instance
     type(process_library_t), pointer :: prclib_saved
     integer :: i
     logical :: res_include_trivial
     logical :: combined_integration
     integer :: selected_mci
     selected_mci = 0
     if (debug_on) call msg_debug (D_CORE, "entry_init")
     if (debug_on) call msg_debug (D_CORE, "process_id", process_id)
     call prepare_process &
          (master_process, process_id, use_process, integrate, local, global)
     if (signal_is_pending ())  return
 
     if (associated (master_process)) then
        if (.not. master_process%has_matrix_element ()) then
           entry%has_integral = .true.
           entry%process_id = process_id
           entry%valid = .false.
           return
        end if
     else
        call entry%basic_init (local%var_list)
        entry%has_integral = .false.
        entry%process_id = process_id
        call entry%import_process_def_characteristics (local%prclib, process_id)
        entry%valid = .true.
        return
     end if
 
     call entry%basic_init (local%var_list, n_alt)
 
     entry%process_id = process_id
     if (generate .or. integrate) then
        entry%run_id = master_process%get_run_id ()
        process => master_process
     else
        call local%set_log (var_str ("?rebuild_phase_space"), &
             .false., is_known = .true.)
        call local%set_log (var_str ("?check_phs_file"), &
             .false., is_known = .true.)
        call local%set_log (var_str ("?rebuild_grids"), &
             .false., is_known = .true.)
        entry%run_id = &
             local%var_list%get_sval (var_str ("$run_id"))
        if (update_sqme) then
           call prepare_local_process (process, process_id, local)
        else
           process => master_process
        end if
     end if
 
     call entry%import_process_characteristics (process)
 
     allocate (entry%mci_sets (entry%n_mci))
     do i = 1, size (entry%mci_sets)
        call entry%mci_sets(i)%init (i, master_process)
     end do
 
     call entry%import_process_results (master_process)
     call entry%prepare_expressions (local)
 
     if (process%is_nlo_calculation ()) then
        call process%init_nlo_settings (global%var_list)
     end if
     combined_integration = local%get_lval (var_str ("?combined_nlo_integration"))
     if (.not. combined_integration &
          .and. local%get_lval (var_str ("?fixed_order_nlo_events"))) &
               selected_mci = process%extract_active_component_mci ()
     call prepare_process_instance (process_instance, process, local%model, &
          local = local)
 
     if (generate) then
        if (selected_mci > 0) then
           call process%prepare_simulation (selected_mci)
           call process_instance%init_simulation (selected_mci, entry%config%safety_factor, &
                local%get_lval (var_str ("?keep_failed_events")))
        else
           do i = 1, entry%n_mci
              call process%prepare_simulation (i)
              call process_instance%init_simulation (i, entry%config%safety_factor, &
                   local%get_lval (var_str ("?keep_failed_events")))
           end do
       end if
     end if
 
     if (support_resonance_history) then
        prclib_saved => local%prclib
        call entry%setup_resonant_subprocesses (local, process)
        if (entry%has_resonant_subprocess_set) then
           if (signal_is_pending ())  return
           call entry%compile_resonant_subprocesses (local)
           if (signal_is_pending ())  return
           call entry%prepare_resonant_subprocesses (local, global)
           if (signal_is_pending ())  return
           call entry%prepare_resonant_subprocess_instances (local)
        end if
        if (signal_is_pending ())  return
        if (associated (prclib_saved))  call local%update_prclib (prclib_saved)
     end if
 
     call entry%setup_event_transforms (process, local)
 
     call dispatch_qcd (entry%qcd, local%get_var_list_ptr (), local%os_data)
 
     call entry%connect_qcd ()
 
     select type (pcm => process_instance%pcm)
     class is (pcm_instance_nlo_t)
         select type (config => pcm%config)
         type is (pcm_nlo_t)
            if (config%settings%fixed_order_nlo) &
                 call pcm%set_fixed_order_event_mode ()
        end select
     end select
 
     if (present (global)) then
        call entry%connect (process_instance, local%model, global%process_stack)
     else
        call entry%connect (process_instance, local%model, local%process_stack)
     end if
     call entry%setup_expressions ()
 
     entry%model => process%get_model_ptr ()
 
     entry%valid = .true.
 
   end subroutine entry_init
 
 @ %def entry_init
 @
 <<Simulations: entry: TBP>>=
   procedure :: set_active_real_components => entry_set_active_real_components
 <<Simulations: procedures>>=
   subroutine entry_set_active_real_components (entry)
     class(entry_t), intent(inout) :: entry
     integer :: i_active_real
     select type (pcm => entry%instance%pcm)
     class is (pcm_instance_nlo_t)
        i_active_real = entry%instance%get_real_of_mci ()
        if (debug_on) call msg_debug2 (D_CORE, "i_active_real", i_active_real)
        if (associated (entry%evt_powheg)) then
           select type (evt => entry%evt_powheg)
           type is (evt_shower_t)
              if (entry%process%get_component_type(i_active_real) == COMP_REAL_FIN) then
                 if (debug_on) call msg_debug (D_CORE, "Disabling Powheg matching for ", i_active_real)
                 call evt%disable_powheg_matching ()
              else
                 if (debug_on) call msg_debug (D_CORE, "Enabling Powheg matching for ", i_active_real)
                 call evt%enable_powheg_matching ()
              end if
           class default
              call msg_fatal ("powheg-evt should be evt_shower_t!")
           end select
        end if
     end select
   end subroutine entry_set_active_real_components
 
 @ %def entry_set_active_real_components
 @ Part of simulation-entry initialization: set up a process object for
 local use.
 <<Simulations: procedures>>=
   subroutine prepare_local_process (process, process_id, local)
     type(process_t), pointer, intent(inout) :: process
     type(string_t), intent(in) :: process_id
     type(rt_data_t), intent(inout), target :: local
     type(integration_t) :: intg
     call intg%create_process (process_id)
     call intg%init_process (local)
     call intg%setup_process (local, verbose=.false.)
     process => intg%get_process_ptr ()
   end subroutine prepare_local_process
 
 @ %def prepare_local_process
 @ Part of simulation-entry initialization: set up a process instance
 matching the selected process object.
 
 The model that we can provide as an extra argument can modify particle
 settings (polarization) in the density matrices that will be constructed.  It
 does not affect parameters.
 <<Simulations: procedures>>=
   subroutine prepare_process_instance &
     (process_instance, process, model, local)
     type(process_instance_t), pointer, intent(inout) :: process_instance
     type(process_t), intent(inout), target :: process
     class(model_data_t), intent(in), optional :: model
     type(rt_data_t), intent(in), optional, target :: local
     allocate (process_instance)
     call process_instance%init (process)
     if (process%is_nlo_calculation ()) then
        select type (pcm => process_instance%pcm)
        type is (pcm_instance_nlo_t)
           select type (config => pcm%config)
           type is (pcm_nlo_t)
              if (.not. config%settings%combined_integration) &
                   call pcm%set_radiation_event ()
           end select
        end select
        call process%prepare_any_external_code ()
     end if
     call process_instance%setup_event_data (model)
   end subroutine prepare_process_instance
 
 @ %def prepare_process_instance
 @ Part of simulation-entry initialization: query the
 process for basic information.
 <<Simulations: entry: TBP>>=
   procedure, private :: import_process_characteristics &
        => entry_import_process_characteristics
 <<Simulations: procedures>>=
   subroutine entry_import_process_characteristics (entry, process)
     class(entry_t), intent(inout) :: entry
     type(process_t), intent(in), target :: process
     entry%library = process%get_library_name ()
     entry%n_in = process%get_n_in ()
     entry%n_mci = process%get_n_mci ()
   end subroutine entry_import_process_characteristics
 
 @ %def entry_import_process_characteristics
 @ This is the alternative form which applies if there is no process
 entry, but just a process definition which we take from the provided
 [[prclib]] definition library.
 <<Simulations: entry: TBP>>=
   procedure, private :: import_process_def_characteristics &
        => entry_import_process_def_characteristics
 <<Simulations: procedures>>=
   subroutine entry_import_process_def_characteristics (entry, prclib, id)
     class(entry_t), intent(inout) :: entry
     type(process_library_t), intent(in), target :: prclib
     type(string_t), intent(in) :: id
     entry%library = prclib%get_name ()
     entry%n_in = prclib%get_n_in (id)
   end subroutine entry_import_process_def_characteristics
 
 @ %def entry_import_process_def_characteristics
 @ Part of simulation-entry initialization: query the
 process for integration results.
 <<Simulations: entry: TBP>>=
   procedure, private :: import_process_results &
        => entry_import_process_results
 <<Simulations: procedures>>=
   subroutine entry_import_process_results (entry, process)
     class(entry_t), intent(inout) :: entry
     type(process_t), intent(in), target :: process
     if (process%has_integral ()) then
        entry%integral = process%get_integral ()
        entry%error = process%get_error ()
        call entry%set_sigma (entry%integral)
        entry%has_integral = .true.
     end if
   end subroutine entry_import_process_results
 
 @ %def entry_import_process_characteristics
 @ Part of simulation-entry initialization: create expression factory
 objects and store them.
 <<Simulations: entry: TBP>>=
   procedure, private :: prepare_expressions &
        => entry_prepare_expressions
 <<Simulations: procedures>>=
   subroutine entry_prepare_expressions (entry, local)
     class(entry_t), intent(inout) :: entry
     type(rt_data_t), intent(in), target :: local
     type(eval_tree_factory_t) :: expr_factory
     call expr_factory%init (local%pn%selection_lexpr)
     call entry%set_selection (expr_factory)
     call expr_factory%init (local%pn%reweight_expr)
     call entry%set_reweight (expr_factory)
     call expr_factory%init (local%pn%analysis_lexpr)
     call entry%set_analysis (expr_factory)
   end subroutine entry_prepare_expressions
 
 @ %def entry_prepare_expressions
 @ Initializes the list of additional NLO entries.  The routine gets the
 information about how many entries to associate from [[region_data]].
 <<Simulations: entry: TBP>>=
   procedure :: setup_additional_entries => entry_setup_additional_entries
 <<Simulations: procedures>>=
   subroutine entry_setup_additional_entries (entry)
     class(entry_t), intent(inout), target :: entry
     type(entry_t), pointer :: current_entry
     integer :: i, n_phs
     type(evt_nlo_t), pointer :: evt
     integer :: mode
     evt => null ()
     select type (pcm => entry%instance%pcm)
     class is (pcm_instance_nlo_t)
        select type (config => pcm%config)
        type is (pcm_nlo_t)
           n_phs = config%region_data%n_phs
        end select
     end select
     select type (entry)
     type is (entry_t)
        current_entry => entry
        current_entry%first => entry
        call get_nlo_evt_ptr (current_entry, evt, mode)
        if (mode > EVT_NLO_SEPARATE_BORNLIKE) then
           allocate (evt%particle_set_radiated (n_phs + 1))
           evt%event_deps%n_phs = n_phs
           evt%qcd = entry%qcd
           do i = 1, n_phs
              allocate (current_entry%next)
              current_entry%next%first => current_entry%first
              current_entry => current_entry%next
              call entry%copy_entry (current_entry)
              current_entry%i_event = i
           end do
        else
           allocate (evt%particle_set_radiated (1))
        end if
     end select
   contains
     subroutine get_nlo_evt_ptr (entry, evt, mode)
       type(entry_t), intent(in), target :: entry
       type(evt_nlo_t), intent(out), pointer :: evt
       integer, intent(out) :: mode
       class(evt_t), pointer :: current_evt
       evt => null ()
       current_evt => entry%transform_first
       do
          select type (current_evt)
          type is (evt_nlo_t)
             evt => current_evt
             mode = evt%mode
             exit
          end select
          if (associated (current_evt%next)) then
             current_evt => current_evt%next
          else
             call msg_fatal ("evt_nlo not in list of event transforms")
          end if
       end do
     end subroutine get_nlo_evt_ptr
   end subroutine entry_setup_additional_entries
 
 @ %def entry_setup_additional_entries
 @
 <<Simulations: entry: TBP>>=
   procedure :: get_first => entry_get_first
 <<Simulations: procedures>>=
   function entry_get_first (entry) result (entry_out)
     class(entry_t), intent(in), target :: entry
     type(entry_t), pointer :: entry_out
     entry_out => null ()
     select type (entry)
     type is (entry_t)
        if (entry%is_nlo ()) then
           entry_out => entry%first
        else
           entry_out => entry
        end if
     end select
   end function entry_get_first
 
 @ %def entry_get_first
 @
 <<Simulations: entry: TBP>>=
   procedure :: get_next => entry_get_next
 <<Simulations: procedures>>=
   function entry_get_next (entry) result (next_entry)
      class(entry_t), intent(in) :: entry
      type(entry_t), pointer :: next_entry
      next_entry => null ()
      if (associated (entry%next)) then
         next_entry => entry%next
      else
         call msg_fatal ("Get next entry: No next entry")
      end if
   end function entry_get_next
 
 @ %def entry_get_next
 @
 <<Simulations: entry: TBP>>=
   procedure :: count_nlo_entries => entry_count_nlo_entries
 <<Simulations: procedures>>=
   function entry_count_nlo_entries (entry) result (n)
     class(entry_t), intent(in), target :: entry
     integer :: n
     type(entry_t), pointer :: current_entry
     n = 1
     if (.not. associated (entry%next)) then
        return
     else
        current_entry => entry%next
        do
           n = n + 1
           if (.not. associated (current_entry%next)) exit
           current_entry => current_entry%next
        end do
     end if
   end function entry_count_nlo_entries
 
 @ %def entry_count_nlo_entries
 @
 <<Simulations: entry: TBP>>=
   procedure :: reset_nlo_counter => entry_reset_nlo_counter
 <<Simulations: procedures>>=
   subroutine entry_reset_nlo_counter (entry)
     class(entry_t), intent(inout) :: entry
     class(evt_t), pointer :: evt
     evt => entry%transform_first
     do
        select type (evt)
        type is (evt_nlo_t)
           evt%i_evaluation = 0
           exit
        end select
        if (associated (evt%next)) evt => evt%next
    end do
   end subroutine entry_reset_nlo_counter
 
 @ %def entry_reset_nlo_counter
 @
 <<Simulations: entry: TBP>>=
   procedure :: determine_if_powheg_matching => entry_determine_if_powheg_matching
 <<Simulations: procedures>>=
   subroutine entry_determine_if_powheg_matching (entry)
      class(entry_t), intent(inout) :: entry
      class(evt_t), pointer :: current_transform
      if (associated (entry%transform_first)) then
         current_transform => entry%transform_first
         do
            select type (current_transform)
            type is (evt_shower_t)
               if (current_transform%contains_powheg_matching ()) &
                   entry%evt_powheg => current_transform
               exit
            end select
            if (associated (current_transform%next)) then
               current_transform => current_transform%next
            else
               exit
            end if
         end do
      end if
   end subroutine entry_determine_if_powheg_matching
 
 @ %def entry_determine_if_powheg_matching
 @ Part of simulation-entry initialization: dispatch event transforms
 (decay, shower) as requested.  If a transform is not applicable or
 switched off via some variable, it will be skipped.
 
 Regarding resonances/decays: these two transforms are currently mutually
 exclusive.  Resonance insertion will not be applied if there is an
 unstable particle in the game.
 <<Simulations: entry: TBP>>=
   procedure, private :: setup_event_transforms &
        => entry_setup_event_transforms
 <<Simulations: procedures>>=
   subroutine entry_setup_event_transforms (entry, process, local)
     class(entry_t), intent(inout) :: entry
     type(process_t), intent(inout), target :: process
     type(rt_data_t), intent(in), target :: local
     class(evt_t), pointer :: evt
     type(var_list_t), pointer :: var_list
     logical :: enable_isr_handler
     logical :: enable_epa_handler
     logical :: enable_fixed_order
     logical :: enable_shower
     var_list => local%get_var_list_ptr ()
     enable_isr_handler = local%get_lval (var_str ("?isr_handler"))
     enable_epa_handler = local%get_lval (var_str ("?epa_handler"))
     if (enable_isr_handler .or. enable_epa_handler) then
        call dispatch_evt_isr_epa_handler (evt, local%var_list)
        if (associated (evt))  call entry%import_transform (evt)
     end if
     if (process%contains_unstable (local%model)) then
        call dispatch_evt_decay (evt, local%var_list)
        if (associated (evt))  call entry%import_transform (evt)
     else if (entry%resonant_subprocess_set%is_active ()) then
        call dispatch_evt_resonance (evt, local%var_list, &
             entry%resonant_subprocess_set%get_resonance_history_set (), &
             entry%resonant_subprocess_set%get_libname ())
        if (associated (evt)) then
           call entry%resonant_subprocess_set%connect_transform (evt)
           call entry%resonant_subprocess_set%set_on_shell_limit &
                (local%get_rval (var_str ("resonance_on_shell_limit")))
           call entry%resonant_subprocess_set%set_on_shell_turnoff &
                (local%get_rval (var_str ("resonance_on_shell_turnoff")))
           call entry%resonant_subprocess_set%set_background_factor &
                (local%get_rval (var_str ("resonance_background_factor")))
           call entry%import_transform (evt)
        end if
     end if
     enable_fixed_order = local%get_lval (var_str ("?fixed_order_nlo_events"))
     if (enable_fixed_order) then
        if (local%get_lval (var_str ("?unweighted"))) &
           call msg_fatal ("NLO Fixed Order events have to be generated with &
                           &?unweighted = false")
        call dispatch_evt_nlo (evt, local%get_lval (var_str ("?keep_failed_events")))
        call entry%import_transform (evt)
     end if
     enable_shower = local%get_lval (var_str ("?allow_shower")) .and. &
             (local%get_lval (var_str ("?ps_isr_active")) &
             .or. local%get_lval (var_str ("?ps_fsr_active")) &
             .or. local%get_lval (var_str ("?muli_active")) &
             .or. local%get_lval (var_str ("?mlm_matching")) &
             .or. local%get_lval (var_str ("?ckkw_matching")) &
             .or. local%get_lval (var_str ("?powheg_matching")))
     if (enable_shower) then
        call dispatch_evt_shower (evt, var_list, local%model, &
             local%fallback_model, local%os_data, local%beam_structure, &
             process)
        call entry%import_transform (evt)
     end if
     if (local%get_lval (var_str ("?hadronization_active"))) then
        call dispatch_evt_hadrons (evt, var_list, local%fallback_model)
        call entry%import_transform (evt)
     end if
   end subroutine entry_setup_event_transforms
 
 @ %def entry_setup_event_transforms
 @ Compute weights.  The integral in the argument is the sum of integrals for
 all processes in the sample.  After computing the process weights, we repeat
 the normalization procedure for the process components.
 <<Simulations: entry: TBP>>=
   procedure :: init_mci_selector => entry_init_mci_selector
 <<Simulations: procedures>>=
   subroutine entry_init_mci_selector (entry, negative_weights)
     class(entry_t), intent(inout), target :: entry
     logical, intent(in), optional :: negative_weights
     type(entry_t), pointer :: current_entry
     integer :: i, j, k
     if (debug_on) call msg_debug (D_CORE, "entry_init_mci_selector")
     if (entry%has_integral) then
        select type (entry)
        type is (entry_t)
           current_entry => entry
           do j = 1, current_entry%count_nlo_entries ()
              if (j > 1) current_entry => current_entry%get_next ()
              do k = 1, size(current_entry%mci_sets%integral)
                 if (debug_on) call msg_debug (D_CORE, "current_entry%mci_sets(k)%integral", &
                      current_entry%mci_sets(k)%integral)
              end do
              call current_entry%mci_selector%init &
                   (current_entry%mci_sets%integral, negative_weights)
              do i = 1, current_entry%n_mci
                 current_entry%mci_sets(i)%weight_mci = &
                    current_entry%mci_selector%get_weight (i)
              end do
           end do
        end select
     end if
   end subroutine entry_init_mci_selector
 
 @ %def entry_init_mci_selector
 @ Select a MCI entry, using the embedded random-number generator.
 <<Simulations: entry: TBP>>=
   procedure :: select_mci => entry_select_mci
 <<Simulations: procedures>>=
   function entry_select_mci (entry) result (i_mci)
     class(entry_t), intent(inout) :: entry
     integer :: i_mci
     if (debug_on) call msg_debug2 (D_CORE, "entry_select_mci")
     i_mci = entry%process%extract_active_component_mci ()
     if (i_mci == 0) call entry%mci_selector%generate (entry%rng, i_mci)
     if (debug_on) call msg_debug2 (D_CORE, "i_mci", i_mci)
   end function entry_select_mci
 
 @ %def entry_select_mci
 @ Record an event for this entry, i.e., increment the appropriate counters.
 <<Simulations: entry: TBP>>=
   procedure :: record => entry_record
 <<Simulations: procedures>>=
   subroutine entry_record (entry, i_mci, from_file)
     class(entry_t), intent(inout) :: entry
     integer, intent(in) :: i_mci
     logical, intent(in), optional :: from_file
     real(default) :: weight, excess
     integer :: n_dropped
     weight = entry%get_weight_prc ()
     excess = entry%get_excess_prc ()
     n_dropped = entry%get_n_dropped ()
     call entry%counter%record (weight, excess, n_dropped, from_file)
     if (i_mci > 0) then
        call entry%mci_sets(i_mci)%counter%record (weight, excess)
     end if
   end subroutine entry_record
 
 @ %def entry_record
 @ Update and restore the process core that this entry accesses, when
 parameters change.  If explicit arguments [[model]], [[qcd]], or
 [[helicity_selection]] are provided, use those.  Otherwise use the
 parameters stored in the process object.
 <<Simulations: entry: TBP>>=
   procedure :: update_process => entry_update_process
   procedure :: restore_process => entry_restore_process
 <<Simulations: procedures>>=
   subroutine entry_update_process &
        (entry, model, qcd, helicity_selection)
     class(entry_t), intent(inout) :: entry
     class(model_data_t), intent(in), optional, target :: model
     type(qcd_t), intent(in), optional :: qcd
     type(helicity_selection_t), intent(in), optional :: helicity_selection
     type(process_t), pointer :: process
     class(prc_core_t), allocatable :: core
     integer :: i, n_terms
     class(model_data_t), pointer :: model_local
     type(qcd_t) :: qcd_local
     if (present (model)) then
        model_local => model
     else
        model_local => entry%model
     end if
     if (present (qcd)) then
        qcd_local = qcd
     else
        qcd_local = entry%qcd
     end if
     process => entry%get_process_ptr ()
 
     n_terms = process%get_n_terms ()
     allocate (entry%core_safe (n_terms))
     do i = 1, n_terms
        if (process%has_matrix_element (i, is_term_index = .true.)) then
           call process%extract_core (i, core)
           call dispatch_core_update (core, &
                model_local, helicity_selection, qcd_local, &
                entry%core_safe(i)%core)
           call process%restore_core (i, core)
        end if
     end do
   end subroutine entry_update_process
 
   subroutine entry_restore_process (entry)
     class(entry_t), intent(inout) :: entry
     type(process_t), pointer :: process
     class(prc_core_t), allocatable :: core
     integer :: i, n_terms
     process => entry%get_process_ptr ()
     n_terms = process%get_n_terms ()
     do i = 1, n_terms
        if (process%has_matrix_element (i, is_term_index = .true.)) then
           call process%extract_core (i, core)
           call dispatch_core_restore (core, entry%core_safe(i)%core)
           call process%restore_core (i, core)
        end if
     end do
     deallocate (entry%core_safe)
   end subroutine entry_restore_process
 
 @ %def entry_update_process
 @ %def entry_restore_process
 <<Simulations: entry: TBP>>=
   procedure :: connect_qcd => entry_connect_qcd
 <<Simulations: procedures>>=
   subroutine entry_connect_qcd (entry)
     class(entry_t), intent(inout), target :: entry
     class(evt_t), pointer :: evt
     evt => entry%transform_first
     do while (associated (evt))
        select type (evt)
        type is (evt_shower_t)
           evt%qcd = entry%qcd
           if (allocated (evt%matching)) then
              evt%matching%qcd = entry%qcd
           end if
        end select
        evt => evt%next
     end do
   end subroutine entry_connect_qcd
 
 @ %def entry_connect_qcd
 @
 \subsection{Handling resonant subprocesses}
 Resonant subprocesses are required if we want to determine resonance histories
 when generating events.  The feature is optional, to be switched on by
 the user.
 
 This procedure initializes a new, separate process library that
 contains copies of the current process, restricted to the relevant
 resonance histories.  (If this library exists already, it is just
 kept.)  The histories can be extracted from the process object.
 
 The code has to match the assignments in
 [[create_resonant_subprocess_library]].  The library may already
 exist -- in that case, here it will be recovered without recompilation.
 <<Simulations: entry: TBP>>=
   procedure :: setup_resonant_subprocesses &
        => entry_setup_resonant_subprocesses
 <<Simulations: procedures>>=
   subroutine entry_setup_resonant_subprocesses (entry, global, process)
     class(entry_t), intent(inout) :: entry
     type(rt_data_t), intent(inout), target :: global
     type(process_t), intent(in), target :: process
     type(string_t) :: libname
     type(resonance_history_set_t) :: res_history_set
     type(process_library_t), pointer :: lib
     type(process_component_def_t), pointer :: process_component_def
     logical :: req_resonant, library_exist
     integer :: i_component
     libname = process%get_library_name ()
     lib => global%prclib_stack%get_library_ptr (libname)
     entry%has_resonant_subprocess_set = lib%req_resonant (process%get_id ())
     if (entry%has_resonant_subprocess_set) then
        libname = get_libname_res (process%get_id ())
        call entry%resonant_subprocess_set%init (process%get_n_components ())
        call entry%resonant_subprocess_set%create_library &
             (libname, global, library_exist)
        do i_component = 1, process%get_n_components ()
           call process%extract_resonance_history_set &
                (res_history_set, i_component = i_component)
           call entry%resonant_subprocess_set%fill_resonances &
                (res_history_set, i_component)
           if (.not. library_exist) then
              process_component_def &
                   => process%get_component_def_ptr (i_component)
              call entry%resonant_subprocess_set%add_to_library &
                   (i_component, &
                   process_component_def%get_prt_spec_in (), &
                   process_component_def%get_prt_spec_out (), &
                   global)
           end if
        end do
        call entry%resonant_subprocess_set%freeze_library (global)
     end if
   end subroutine entry_setup_resonant_subprocesses
 
 @ %def entry_setup_resonant_subprocesses
 @ Compile the resonant-subprocesses library.  The library is assumed
 to be the current library in the [[global]] object.  This is a simple wrapper.
 <<Simulations: entry: TBP>>=
   procedure :: compile_resonant_subprocesses &
        => entry_compile_resonant_subprocesses
 <<Simulations: procedures>>=
   subroutine entry_compile_resonant_subprocesses (entry, global)
     class(entry_t), intent(inout) :: entry
     type(rt_data_t), intent(inout), target :: global
     call entry%resonant_subprocess_set%compile_library (global)
   end subroutine entry_compile_resonant_subprocesses
 
 @ %def entry_compile_resonant_subprocesses
 @ Prepare process objects for the resonant-subprocesses library.  The
 process objects are appended to the global process stack.  We
 initialize the processes, such that we can evaluate matrix elements,
 but we do not need to integrate them.
 <<Simulations: entry: TBP>>=
   procedure :: prepare_resonant_subprocesses &
        => entry_prepare_resonant_subprocesses
 <<Simulations: procedures>>=
   subroutine entry_prepare_resonant_subprocesses (entry, local, global)
     class(entry_t), intent(inout) :: entry
     type(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(inout), optional, target :: global
     call entry%resonant_subprocess_set%prepare_process_objects (local, global)
   end subroutine entry_prepare_resonant_subprocesses
 
 @ %def entry_prepare_resonant_subprocesses
 @ Prepare process instances.  They are linked to their corresponding process
 objects.  Both, process and instance objects, are allocated as anonymous
 targets inside the [[resonant_subprocess_set]] component.
 
 NOTE: those anonymous object are likely forgotten during finalization of the
 parent [[event_t]] (extended as [[entry_t]]) object.  This should be checked!
 The memory leak is probably harmless as long as the event object is created
 once per run, not once per event.
 <<Simulations: entry: TBP>>=
   procedure :: prepare_resonant_subprocess_instances &
        => entry_prepare_resonant_subprocess_instances
 <<Simulations: procedures>>=
   subroutine entry_prepare_resonant_subprocess_instances (entry, global)
     class(entry_t), intent(inout) :: entry
     type(rt_data_t), intent(in), target :: global
     call entry%resonant_subprocess_set%prepare_process_instances (global)
   end subroutine entry_prepare_resonant_subprocess_instances
 
 @ %def entry_prepare_resonant_subprocess_instances
 @ Display the resonant subprocesses.  This includes, upon request, the
 resonance set that defines those subprocess, and a short or long account of the
 process objects themselves.
 <<Simulations: entry: TBP>>=
   procedure :: write_resonant_subprocess_data &
        => entry_write_resonant_subprocess_data
 <<Simulations: procedures>>=
   subroutine entry_write_resonant_subprocess_data (entry, unit)
     class(entry_t), intent(in) :: entry
     integer, intent(in), optional :: unit
     integer :: u, i
     u = given_output_unit (unit)
     call entry%resonant_subprocess_set%write (unit)
     write (u, "(1x,A,I0)")  "Resonant subprocesses refer to &
             &process component #", 1
   end subroutine entry_write_resonant_subprocess_data
 
 @ %def entry_write_resonant_subprocess_data
 @ Display of the master process for the current event, for diagnostics.
 <<Simulations: entry: TBP>>=
   procedure :: write_process_data => entry_write_process_data
 <<Simulations: procedures>>=
   subroutine entry_write_process_data &
        (entry, unit, show_process, show_instance, verbose)
     class(entry_t), intent(in) :: entry
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: show_process
     logical, intent(in), optional :: show_instance
     logical, intent(in), optional :: verbose
     integer :: u, i
     logical :: s_proc, s_inst, verb
     type(process_t), pointer :: process
     type(process_instance_t), pointer :: instance
     u = given_output_unit (unit)
     s_proc = .false.;  if (present (show_process))  s_proc = show_process
     s_inst = .false.;  if (present (show_instance))  s_inst = show_instance
     verb = .false.;  if (present (verbose))  verb = verbose
     if (s_proc .or. s_inst) then
        write (u, "(1x,A,':')")  "Process data"
        if (s_proc) then
           process => entry%process
           if (associated (process)) then
              if (verb) then
                 call write_separator (u, 2)
                 call process%write (.false., u)
              else
                 call process%show (u, verbose=.false.)
              end if
           else
              write (u, "(3x,A)")  "[not associated]"
           end if
        end if
        if (s_inst) then
           instance => entry%instance
           if (associated (instance)) then
              if (verb) then
                 call instance%write (u)
              else
                 call instance%write_header (u)
              end if
           else
              write (u, "(3x,A)")  "Process instance: [not associated]"
           end if
        end if
     end if
   end subroutine entry_write_process_data
 
 @ %def entry_write_process_data
 @
 \subsection{Entries for alternative environment}
 Entries for alternate environments.  [No additional components
 anymore, so somewhat redundant.]
 <<Simulations: types>>=
   type, extends (entry_t) :: alt_entry_t
    contains
    <<Simulations: alt entry: TBP>>
   end type alt_entry_t
 
 @ %def alt_entry_t
  The alternative entries are there to re-evaluate the event, given
 momenta, in a different context.
 
 Therefore, we allocate a local process object and use this as the
 reference for the local process instance, when initializing the entry.
 We temporarily import the [[process]] object into an [[integration_t]]
 wrapper, to take advantage of the associated methods.  The local
 process object is built in the context of the current environment,
 here called [[global]].  Then, we initialize the process instance.
 
 The [[master_process]] object contains the integration results to which we
 refer when recalculating an event.  Therefore, we use this object instead of
 the locally built [[process]] when we extract the integration results.
 
 The locally built [[process]] object should be finalized when done.  It
 remains accessible via the [[event_t]] base object of [[entry]], which
 contains pointers to the process and instance.
 <<Simulations: alt entry: TBP>>=
   procedure :: init_alt => alt_entry_init
 <<Simulations: procedures>>=
   subroutine alt_entry_init (entry, process_id, master_process, local)
     class(alt_entry_t), intent(inout), target :: entry
     type(string_t), intent(in) :: process_id
     type(process_t), intent(in), target :: master_process
     type(rt_data_t), intent(inout), target :: local
     type(process_t), pointer :: process
     type(process_instance_t), pointer :: process_instance
     type(string_t) :: run_id
     integer :: i
 
     call msg_message ("Simulate: initializing alternate process setup ...")
 
     run_id = &
          local%var_list%get_sval (var_str ("$run_id"))
     call local%set_log (var_str ("?rebuild_phase_space"), &
          .false., is_known = .true.)
     call local%set_log (var_str ("?check_phs_file"), &
          .false., is_known = .true.)
     call local%set_log (var_str ("?rebuild_grids"), &
          .false., is_known = .true.)
 
     call entry%basic_init (local%var_list)
 
     call prepare_local_process (process, process_id, local)
     entry%process_id = process_id
     entry%run_id = run_id
 
     call entry%import_process_characteristics (process)
 
     allocate (entry%mci_sets (entry%n_mci))
     do i = 1, size (entry%mci_sets)
        call entry%mci_sets(i)%init (i, master_process)
     end do
 
     call entry%import_process_results (master_process)
     call entry%prepare_expressions (local)
 
     call prepare_process_instance (process_instance, process, local%model)
     call entry%setup_event_transforms (process, local)
 
     call entry%connect (process_instance, local%model, local%process_stack)
     call entry%setup_expressions ()
 
     entry%model => process%get_model_ptr ()
 
     call msg_message ("...  alternate process setup complete.")
 
   end subroutine alt_entry_init
 
 @ %def alt_entry_init
 @ Copy the particle set from the master entry to the alternate entry.
 This is the particle set of the hard process.
 <<Simulations: alt entry: TBP>>=
   procedure :: fill_particle_set => entry_fill_particle_set
 <<Simulations: procedures>>=
   subroutine entry_fill_particle_set (alt_entry, entry)
     class(alt_entry_t), intent(inout) :: alt_entry
     class(entry_t), intent(in), target :: entry
     type(particle_set_t) :: pset
     call entry%get_hard_particle_set (pset)
     call alt_entry%set_hard_particle_set (pset)
     call pset%final ()
   end subroutine entry_fill_particle_set
 
 @ %def particle_set_copy_prt
 @
 \subsection{The simulation type}
 Each simulation object corresponds to an event sample, identified by
 the [[sample_id]].
 
 The simulation may cover several processes simultaneously.  All
 process-specific data, including the event records, are stored in the
 [[entry]] subobjects.  The [[current]] index indicates which record
 was selected last. [[version]] is foreseen to contain a tag on the \whizard\
 event file version. It can be
 <<Simulations: public>>=
   public :: simulation_t
 <<Simulations: types>>=
   type :: simulation_t
      private
      type(rt_data_t), pointer :: local => null ()
      type(string_t) :: sample_id
      logical :: unweighted = .true.
      logical :: negative_weights = .false.
      logical :: support_resonance_history = .false.
      logical :: respect_selection = .true.
      integer :: norm_mode = NORM_UNDEFINED
      logical :: update_sqme = .false.
      logical :: update_weight = .false.
      logical :: update_event = .false.
      logical :: recover_beams = .false.
      logical :: pacify = .false.
      integer :: n_max_tries = 10000
      integer :: n_prc = 0
      integer :: n_alt = 0
      logical :: has_integral = .false.
      logical :: valid = .false.
      real(default) :: integral = 0
      real(default) :: error = 0
      integer :: version = 1
      character(32) :: md5sum_prc = ""
      character(32) :: md5sum_cfg = ""
      character(32), dimension(:), allocatable :: md5sum_alt
      type(entry_t), dimension(:), allocatable :: entry
      type(alt_entry_t), dimension(:,:), allocatable :: alt_entry
      type(selector_t) :: process_selector
      integer :: n_evt_requested = 0
      integer :: event_index_offset = 0
      logical :: event_index_set = .false.
      integer :: event_index = 0
      integer :: split_n_evt = 0
      integer :: split_n_kbytes = 0
      integer :: split_index = 0
      type(counter_t) :: counter
      class(rng_t), allocatable :: rng
      integer :: i_prc = 0
      integer :: i_mci = 0
      real(default) :: weight = 0
      real(default) :: excess = 0
      integer :: n_dropped = 0
    contains
    <<Simulations: simulation: TBP>>
   end type simulation_t
 
 @ %def simulation_t
 @ Output.  [[write_config]] writes just the configuration.  [[write]]
 as a method of the base type [[event_t]]
 writes the current event and process instance, depending on options.
 <<Simulations: simulation: TBP>>=
   procedure :: write => simulation_write
 <<Simulations: procedures>>=
   subroutine simulation_write (object, unit, testflag)
     class(simulation_t), intent(in) :: object
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: testflag
     logical :: pacified
     integer :: u, i
     u = given_output_unit (unit)
     pacified = object%pacify;  if (present (testflag))  pacified = testflag
     call write_separator (u, 2)
     write (u, "(1x,A,A,A)")  "Event sample: '", char (object%sample_id), "'"
     write (u, "(3x,A,I0)")  "Processes    = ", object%n_prc
     if (object%n_alt > 0) then
        write (u, "(3x,A,I0)")  "Alt.wgts     = ", object%n_alt
     end if
     write (u, "(3x,A,L1)")  "Unweighted   = ", object%unweighted
     write (u, "(3x,A,A)")   "Event norm   = ", &
          char (event_normalization_string (object%norm_mode))
     write (u, "(3x,A,L1)")  "Neg. weights = ", object%negative_weights
     write (u, "(3x,A,L1)")  "Res. history = ", object%support_resonance_history
     write (u, "(3x,A,L1)")  "Respect sel. = ", object%respect_selection
     write (u, "(3x,A,L1)")  "Update sqme  = ", object%update_sqme
     write (u, "(3x,A,L1)")  "Update wgt   = ", object%update_weight
     write (u, "(3x,A,L1)")  "Update event = ", object%update_event
     write (u, "(3x,A,L1)")  "Recov. beams = ", object%recover_beams
     write (u, "(3x,A,L1)")  "Pacify       = ", object%pacify
     write (u, "(3x,A,I0)")  "Max. tries   = ", object%n_max_tries
     if (object%has_integral) then
        if (pacified) then
           write (u, "(3x,A," // FMT_15 // ")")  &
                "Integral     = ", object%integral
           write (u, "(3x,A," // FMT_15 // ")")  &
                "Error        = ", object%error
        else
           write (u, "(3x,A," // FMT_19 // ")")  &
                "Integral     = ", object%integral
           write (u, "(3x,A," // FMT_19 // ")")  &
                "Error        = ", object%error
        end if
     else
        write (u, "(3x,A)")  "Integral     = [undefined]"
     end if
     write (u, "(3x,A,L1)")  "Sim. valid   = ", object%valid
     write (u, "(3x,A,I0)")  "Ev.file ver. = ", object%version
     if (object%md5sum_prc /= "") then
        write (u, "(3x,A,A,A)")  "MD5 sum (proc)   = '", object%md5sum_prc, "'"
     end if
     if (object%md5sum_cfg /= "") then
        write (u, "(3x,A,A,A)")  "MD5 sum (config) = '", object%md5sum_cfg, "'"
     end if
     write (u, "(3x,A,I0)")  "Events requested  = ", object%n_evt_requested
     if (object%event_index_offset /= 0) then
        write (u, "(3x,A,I0)")  "Event index offset= ", object%event_index_offset
     end if
     if (object%event_index_set) then
        write (u, "(3x,A,I0)")  "Event index       = ", object%event_index
     end if
     if (object%split_n_evt > 0 .or. object%split_n_kbytes > 0) then
        write (u, "(3x,A,I0)")  "Events per file   = ", object%split_n_evt
        write (u, "(3x,A,I0)")  "KBytes per file   = ", object%split_n_kbytes
        write (u, "(3x,A,I0)")  "First file index  = ", object%split_index
     end if
     call object%counter%write (u)
     call write_separator (u)
     if (object%i_prc /= 0) then
        write (u, "(1x,A)")  "Current event:"
        write (u, "(3x,A,I0,A,A)")  "Process #", &
             object%i_prc, ": ", &
             char (object%entry(object%i_prc)%process_id)
        write (u, "(3x,A,I0)")  "MCI set #", object%i_mci
        write (u, "(3x,A," // FMT_19 // ")")  "Weight    = ", object%weight
        if (.not. vanishes (object%excess)) &
             write (u, "(3x,A," // FMT_19 // ")")  "Excess    = ", object%excess
        write (u, "(3x,A,I0)")  "Zero-weight events dropped = ", object%n_dropped
     else
        write (u, "(1x,A,I0,A,A)")  "Current event: [undefined]"
     end if
     call write_separator (u)
     if (allocated (object%rng)) then
        call object%rng%write (u)
     else
        write (u, "(3x,A)")  "Random-number generator: [undefined]"
     end if
     if (allocated (object%entry)) then
        do i = 1, size (object%entry)
           if (i == 1) then
              call write_separator (u, 2)
           else
              call write_separator (u)
           end if
           write (u, "(1x,A,I0,A)") "Process #", i, ":"
           call object%entry(i)%write_config (u, pacified)
        end do
     end if
     call write_separator (u, 2)
   end subroutine simulation_write
 
 @ %def simulation_write
 @ Write the current event record.  If an explicit index is given,
 write that event record.
 
 We implement writing to [[unit]] (event contents / debugging format)
 and writing to an [[eio]] event stream (storage). We include a [[testflag]]
 in order to suppress numerical noise in the testsuite.
 <<Simulations: simulation: TBP>>=
   generic :: write_event => write_event_unit
   procedure :: write_event_unit => simulation_write_event_unit
 <<Simulations: procedures>>=
   subroutine simulation_write_event_unit &
        (object, unit, i_prc, verbose, testflag)
     class(simulation_t), intent(in) :: object
     integer, intent(in), optional :: unit
     logical, intent(in), optional :: verbose
     integer, intent(in), optional :: i_prc
     logical, intent(in), optional :: testflag
     logical :: pacified
     integer :: current
     pacified = .false.;  if (present(testflag)) pacified = testflag
     pacified = pacified .or. object%pacify
     if (present (i_prc)) then
        current = i_prc
     else
        current = object%i_prc
     end if
     if (current > 0) then
        call object%entry(current)%write (unit, verbose = verbose, &
             testflag = pacified)
     else
        call msg_fatal ("Simulation: write event: no process selected")
     end if
   end subroutine simulation_write_event_unit
 
 @ %def simulation_write_event
 @ This writes one of the alternate events, if allocated.
 <<Simulations: simulation: TBP>>=
   procedure :: write_alt_event => simulation_write_alt_event
 <<Simulations: procedures>>=
   subroutine simulation_write_alt_event (object, unit, j_alt, i_prc, &
        verbose, testflag)
     class(simulation_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer, intent(in), optional :: j_alt
     integer, intent(in), optional :: i_prc
     logical, intent(in), optional :: verbose
     logical, intent(in), optional :: testflag
     integer :: i, j
     if (present (j_alt)) then
        j = j_alt
     else
        j = 1
     end if
     if (present (i_prc)) then
        i = i_prc
     else
        i = object%i_prc
     end if
     if (i > 0) then
        if (j> 0 .and. j <= object%n_alt) then
           call object%alt_entry(i,j)%write (unit, verbose = verbose, &
                testflag = testflag)
        else
           call msg_fatal ("Simulation: write alternate event: out of range")
        end if
     else
        call msg_fatal ("Simulation: write alternate event: no process selected")
     end if
   end subroutine simulation_write_alt_event
 
 @ %def simulation_write_alt_event
 @ This writes the contents of the resonant subprocess set in the current event
 record.
 <<Simulations: simulation: TBP>>=
   procedure :: write_resonant_subprocess_data &
        => simulation_write_resonant_subprocess_data
 <<Simulations: procedures>>=
   subroutine simulation_write_resonant_subprocess_data (object, unit, i_prc)
     class(simulation_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer, intent(in), optional :: i_prc
     integer :: i
     if (present (i_prc)) then
        i = i_prc
     else
        i = object%i_prc
     end if
     call object%entry(i)%write_resonant_subprocess_data (unit)
   end subroutine simulation_write_resonant_subprocess_data
 
 @ %def simulation_write_resonant_subprocess_data
 @ The same for the master process, as an additional debugging aid.
 <<Simulations: simulation: TBP>>=
   procedure :: write_process_data &
        => simulation_write_process_data
 <<Simulations: procedures>>=
   subroutine simulation_write_process_data &
        (object, unit, i_prc, &
        show_process, show_instance, verbose)
     class(simulation_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer, intent(in), optional :: i_prc
     logical, intent(in), optional :: show_process
     logical, intent(in), optional :: show_instance
     logical, intent(in), optional :: verbose
     integer :: i
     if (present (i_prc)) then
        i = i_prc
     else
        i = object%i_prc
     end if
     call object%entry(i)%write_process_data &
          (unit, show_process, show_instance, verbose)
   end subroutine simulation_write_process_data
 
 @ %def simulation_write_process_data
 @ Finalizer.
 <<Simulations: simulation: TBP>>=
   procedure :: final => simulation_final
 <<Simulations: procedures>>=
   subroutine simulation_final (object)
     class(simulation_t), intent(inout) :: object
     integer :: i, j
     if (allocated (object%entry)) then
        do i = 1, size (object%entry)
           call object%entry(i)%final ()
        end do
     end if
     if (allocated (object%alt_entry)) then
        do j = 1, size (object%alt_entry, 2)
           do i = 1, size (object%alt_entry, 1)
              call object%alt_entry(i,j)%final ()
           end do
        end do
     end if
     if (allocated (object%rng))  call object%rng%final ()
   end subroutine simulation_final
 
 @ %def simulation_final
 @ Initialization.  We can deduce all data from the given list of
 process IDs and the global data set.  The process objects are taken
 from the stack.  Once the individual integrals are known, we add them (and the
 errors), to get the sample integral.
 
 If there are alternative environments, we suspend initialization for
 setting up alternative process objects, then restore the master
 process and its parameters.  The generator or rescanner can then
 switch rapidly between processes.
 
 If [[integrate]] is set, we make sure that all affected processes are
 integrated before simulation.  This is necessary if we want to actually
 generate events.  If [[integrate]] is unset, we don't need the integral
 because we just rescan existing events.  In that case, we just need compiled
 matrix elements.
 
 If [[generate]] is set, we prepare for actually generating events.  Otherwise,
 we may only read and rescan events.
 <<Simulations: simulation: TBP>>=
   procedure :: init => simulation_init
 <<Simulations: procedures>>=
   subroutine simulation_init (simulation, &
        process_id, integrate, generate, local, global, alt_env)
     class(simulation_t), intent(out), target :: simulation
     type(string_t), dimension(:), intent(in) :: process_id
     logical, intent(in) :: integrate, generate
     type(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(inout), optional, target :: global
     type(rt_data_t), dimension(:), intent(inout), optional, target :: alt_env
     class(rng_factory_t), allocatable :: rng_factory
     integer :: next_rng_seed
     type(string_t) :: norm_string, version_string
     logical :: use_process
     integer :: i, j
     type(string_t) :: sample_suffix
   <<Simulations: simulation init: variables>>
     sample_suffix = ""
   <<Simulations: simulation init: init>>
     simulation%local => local
     simulation%sample_id = &
          local%get_sval (var_str ("$sample")) // sample_suffix
     simulation%unweighted = &
          local%get_lval (var_str ("?unweighted"))
     simulation%negative_weights = &
          local%get_lval (var_str ("?negative_weights"))
     simulation%support_resonance_history = &
          local%get_lval (var_str ("?resonance_history"))
     simulation%respect_selection = &
          local%get_lval (var_str ("?sample_select"))
     version_string = &
          local%get_sval (var_str ("$event_file_version"))
     norm_string = &
          local%get_sval (var_str ("$sample_normalization"))
     simulation%norm_mode = &
          event_normalization_mode (norm_string, simulation%unweighted)
     simulation%pacify = &
          local%get_lval (var_str ("?sample_pacify"))
     simulation%event_index_offset = &
          local%get_ival (var_str ("event_index_offset"))
     simulation%n_max_tries = &
          local%get_ival (var_str ("sample_max_tries"))
     simulation%split_n_evt = &
          local%get_ival (var_str ("sample_split_n_evt"))
     simulation%split_n_kbytes = &
          local%get_ival (var_str ("sample_split_n_kbytes"))
     simulation%split_index = &
          local%get_ival (var_str ("sample_split_index"))
     simulation%update_sqme = &
          local%get_lval (var_str ("?update_sqme"))
     simulation%update_weight = &
          local%get_lval (var_str ("?update_weight"))
     simulation%update_event = &
          local%get_lval (var_str ("?update_event"))
     simulation%recover_beams = &
          local%get_lval (var_str ("?recover_beams"))
     simulation%counter%reproduce_xsection = &
          local%get_lval (var_str ("?check_event_weights_against_xsection"))
     use_process = &
          integrate .or. generate &
          .or. simulation%update_sqme &
          .or. simulation%update_weight &
          .or. simulation%update_event &
          .or. present (alt_env)
     select case (size (process_id))
     case (0)
        call msg_error ("Simulation: no process selected")
     case (1)
        write (msg_buffer, "(A,A,A)") &
             "Starting simulation for process '", &
             char (process_id(1)), "'"
        call msg_message ()
     case default
        write (msg_buffer, "(A,A,A)") &
             "Starting simulation for processes '", &
             char (process_id(1)), "' etc."
        call msg_message ()
     end select
     select case (char (version_string))
     case ("", "2.2.4")
        simulation%version = 2
     case ("2.2")
        simulation%version = 1
     case default
        simulation%version = 0
     end select
     if (simulation%version == 0) then
        call msg_fatal ("Event file format '" &
             // char (version_string) &
             // "' is not compatible with this version.")
     end if
     simulation%n_prc = size (process_id)
     allocate (simulation%entry (simulation%n_prc))
     if (present (alt_env)) then
        simulation%n_alt = size (alt_env)
        do i = 1, simulation%n_prc
           call simulation%entry(i)%init (process_id(i), &
                use_process, integrate, generate, &
                simulation%update_sqme, &
                simulation%support_resonance_history, &
                local, global, simulation%n_alt)
           if (signal_is_pending ())  return
        end do
        simulation%valid = any (simulation%entry%valid)
        if (.not. simulation%valid) then
           call msg_error ("Simulate: no process has a valid matrix element.")
           return
        end if
        call simulation%update_processes ()
        allocate (simulation%alt_entry (simulation%n_prc, simulation%n_alt))
        allocate (simulation%md5sum_alt (simulation%n_alt))
        simulation%md5sum_alt = ""
        do j = 1, simulation%n_alt
           do i = 1, simulation%n_prc
              call simulation%alt_entry(i,j)%init_alt (process_id(i), &
                   simulation%entry(i)%get_process_ptr (), alt_env(j))
              if (signal_is_pending ())  return
           end do
        end do
        call simulation%restore_processes ()
     else
        do i = 1, simulation%n_prc
           call simulation%entry(i)%init &
                (process_id(i), &
                use_process, integrate, generate, &
                simulation%update_sqme, &
                simulation%support_resonance_history, &
                local, global)
           call simulation%entry(i)%determine_if_powheg_matching ()
           if (signal_is_pending ())  return
           if (simulation%entry(i)%is_nlo ()) &
                call simulation%entry(i)%setup_additional_entries ()
        end do
        simulation%valid = any (simulation%entry%valid)
        if (.not. simulation%valid) then
           call msg_error ("Simulate: " &
                // "no process has a valid matrix element.")
           return
        end if
     end if
 !!! if this becomes conditional, some ref files will need update (seed change)
 !    if (generate) then
        call dispatch_rng_factory (rng_factory, local%var_list, next_rng_seed)
        call update_rng_seed_in_var_list (local%var_list, next_rng_seed)
        call rng_factory%make (simulation%rng)
 !    end if
     if (all (simulation%entry%has_integral)) then
        simulation%integral = sum (simulation%entry%integral)
        simulation%error = sqrt (sum (simulation%entry%error ** 2))
        simulation%has_integral = .true.
        if (integrate .and. generate) then
           do i = 1, simulation%n_prc
              if (simulation%entry(i)%integral < 0 .and. .not. &
                   simulation%negative_weights) then
                 call msg_fatal ("Integral of process '" // &
                      char (process_id (i)) // "'is negative.")
              end if
           end do
        end if
     else
        if (integrate .and. generate) &
             call msg_error ("Simulation contains undefined integrals.")
     end if
     if (simulation%integral > 0 .or. &
          (simulation%integral < 0 .and. simulation%negative_weights)) then
        simulation%valid = .true.
     else if (generate) then
        call msg_error ("Simulate: " &
             // "sum of process integrals must be positive; skipping.")
        simulation%valid = .false.
     else
        simulation%valid = .true.
     end if
     if (simulation%valid)  call simulation%compute_md5sum ()
   end subroutine simulation_init
 
 @ %def simulation_init
 @
 <<MPI: Simulations: simulation init: variables>>=
   integer :: rank, n_size
 @
 <<MPI: Simulations: simulation init: init>>=
   call mpi_get_comm_id (n_size, rank)
   if (n_size > 1) then
      sample_suffix = var_str ("_") // str (rank)
   end if
 @
 @ The number of events that we want to simulate is determined by the
 settings of [[n_events]], [[luminosity]], and [[?unweighted]].  For
 weighted events, we take [[n_events]] at face value as the number of
 matrix element calls.  For unweighted events, if the process is a
 decay, [[n_events]] is the number of unweighted events.  In these
 cases, the luminosity setting is ignored.
 
 For unweighted events with a scattering process, we calculate the
 event number that corresponds to the luminosity, given the current
 value of the integral.  We then compare this with [[n_events]] and
 choose the larger number.
 <<Simulations: simulation: TBP>>=
   procedure :: compute_n_events => simulation_compute_n_events
 <<Simulations: procedures>>=
   subroutine simulation_compute_n_events (simulation, n_events, var_list)
     class(simulation_t), intent(in) :: simulation
     integer, intent(out) :: n_events
     type(var_list_t) :: var_list
     real(default) :: lumi, x_events_lumi
     integer :: n_events_lumi
     logical :: is_scattering
     n_events = &
          var_list%get_ival (var_str ("n_events"))
     lumi = &
          var_list%get_rval (var_str ("luminosity"))
     if (simulation%unweighted) then
        is_scattering = simulation%entry(1)%n_in == 2
        if (is_scattering) then
           x_events_lumi = abs (simulation%integral * lumi)
           if (x_events_lumi < huge (n_events)) then
              n_events_lumi = nint (x_events_lumi)
           else
              call msg_message ("Simulation: luminosity too large, &
                   &limiting number of events")
              n_events_lumi = huge (n_events)
           end if
           if (n_events_lumi > n_events) then
              call msg_message ("Simulation: using n_events as computed from &
                   &luminosity value")
              n_events = n_events_lumi
           else
              write (msg_buffer, "(A,1x,I0)") &
                   "Simulation: requested number of events =", n_events
              call msg_message ()
              if (.not. vanishes (simulation%integral)) then
                 write (msg_buffer, "(A,1x,ES11.4)") &
                      "            corr. to luminosity [fb-1] = ", &
                      n_events / simulation%integral
                 call msg_message ()
              end if
           end if
        end if
     end if
   end subroutine simulation_compute_n_events
 
 @ %def simulation_compute_n_events
 @ Write the actual efficiency of the simulation run.  We get the total
 number of events stored in the simulation counter and compare this
 with the total number of calls stored in the event entries.
 
 In order not to miscount samples that are partly read from file, use
 the [[generated]] counter, not the [[total]] counter.
 <<Simulations: simulation: TBP>>=
   procedure :: show_efficiency => simulation_show_efficiency
 <<Simulations: procedures>>=
   subroutine simulation_show_efficiency (simulation)
     class(simulation_t), intent(inout) :: simulation
     integer :: n_events, n_calls
     real(default) :: eff
     n_events = simulation%counter%generated
     n_calls = sum (simulation%entry%get_actual_calls_total ())
     if (n_calls > 0) then
        eff = real (n_events, kind=default) / n_calls
        write (msg_buffer, "(A,1x,F6.2,1x,A)") &
             "Events: actual unweighting efficiency =", 100 * eff, "%"
        call msg_message ()
     end if
   end subroutine simulation_show_efficiency
 
 @ %def simulation_show_efficiency
 @
 <<Simulations: simulation: TBP>>=
   procedure :: get_n_nlo_entries => simulation_get_n_nlo_entries
 <<Simulations: procedures>>=
   function simulation_get_n_nlo_entries (simulation, i_prc) result (n_extra)
     class(simulation_t), intent(in) :: simulation
     integer, intent(in) :: i_prc
     integer :: n_extra
     n_extra = simulation%entry(i_prc)%count_nlo_entries ()
   end function simulation_get_n_nlo_entries
 
 @ %def simulation_get_n_nlo_entries
 @ Compute the checksum of the process set.  We retrieve the MD5 sums
 of all processes.  This depends only on the process definitions, while
 parameters are not considered.  The configuration checksum is
 retrieved from the MCI records in the process objects and furthermore
 includes beams, parameters, integration results, etc., so matching the
 latter should guarantee identical physics.
 <<Simulations: simulation: TBP>>=
   procedure :: compute_md5sum => simulation_compute_md5sum
 <<Simulations: procedures>>=
   subroutine simulation_compute_md5sum (simulation)
     class(simulation_t), intent(inout) :: simulation
     type(process_t), pointer :: process
     type(string_t) :: buffer
     integer :: j, i, n_mci, i_mci, n_component, i_component
     if (simulation%md5sum_prc == "") then
        buffer = ""
        do i = 1, simulation%n_prc
           if (.not. simulation%entry(i)%valid) cycle
           process => simulation%entry(i)%get_process_ptr ()
           if (associated (process)) then
              n_component = process%get_n_components ()
              do i_component = 1, n_component
                 if (process%has_matrix_element (i_component)) then
                    buffer = buffer // process%get_md5sum_prc (i_component)
                 end if
              end do
           end if
        end do
        simulation%md5sum_prc = md5sum (char (buffer))
     end if
     if (simulation%md5sum_cfg == "") then
        buffer = ""
        do i = 1, simulation%n_prc
           if (.not. simulation%entry(i)%valid) cycle
           process => simulation%entry(i)%get_process_ptr ()
           if (associated (process)) then
              n_mci = process%get_n_mci ()
              do i_mci = 1, n_mci
                 buffer = buffer // process%get_md5sum_mci (i_mci)
              end do
           end if
        end do
        simulation%md5sum_cfg = md5sum (char (buffer))
     end if
     do j = 1, simulation%n_alt
        if (simulation%md5sum_alt(j) == "") then
           buffer = ""
           do i = 1, simulation%n_prc
              process => simulation%alt_entry(i,j)%get_process_ptr ()
              if (associated (process)) then
                 buffer = buffer // process%get_md5sum_cfg ()
              end if
           end do
           simulation%md5sum_alt(j) = md5sum (char (buffer))
        end if
     end do
   end subroutine simulation_compute_md5sum
 
 @ %def simulation_compute_md5sum
 @ Initialize the process selector, using the entry integrals as process
 weights.
 <<Simulations: simulation: TBP>>=
   procedure :: init_process_selector => simulation_init_process_selector
 <<Simulations: procedures>>=
   subroutine simulation_init_process_selector (simulation)
     class(simulation_t), intent(inout) :: simulation
     integer :: i
     if (simulation%has_integral) then
        call simulation%process_selector%init (simulation%entry%integral, &
             negative_weights = simulation%negative_weights)
        do i = 1, simulation%n_prc
           associate (entry => simulation%entry(i))
             if (.not. entry%valid) then
                call msg_warning ("Process '" // char (entry%process_id) // &
                     "': matrix element vanishes, no events can be generated.")
                cycle
             end if
             call entry%init_mci_selector (simulation%negative_weights)
             entry%process_weight = simulation%process_selector%get_weight (i)
           end associate
        end do
     end if
   end subroutine simulation_init_process_selector
 
 @ %def simulation_init_process_selector
 @ Select a process, using the random-number generator.
 <<Simulations: simulation: TBP>>=
   procedure :: select_prc => simulation_select_prc
 <<Simulations: procedures>>=
   function simulation_select_prc (simulation) result (i_prc)
     class(simulation_t), intent(inout) :: simulation
     integer :: i_prc
     call simulation%process_selector%generate (simulation%rng, i_prc)
   end function simulation_select_prc
 
 @ %def simulation_select_prc
 @ Select a MCI set for the selected process.
 <<Simulations: simulation: TBP>>=
   procedure :: select_mci => simulation_select_mci
 <<Simulations: procedures>>=
   function simulation_select_mci (simulation) result (i_mci)
     class(simulation_t), intent(inout) :: simulation
     integer :: i_mci
     i_mci = 0
     if (simulation%i_prc /= 0) then
        i_mci = simulation%entry(simulation%i_prc)%select_mci ()
     end if
   end function simulation_select_mci
 
 @ %def simulation_select_mci
 @ Generate a predefined number of events.  First select a process and
 a component set, then generate an event for that process and factorize
 the quantum state.  The pair of random numbers can be used for
 factorization.
 
 When generating events, we drop all configurations where the event is
 marked as incomplete.  This happens if the event fails cuts.  In fact,
 such events are dropped already by the sampler if unweighting is in
 effect, so this can happen only for weighted events.  By setting a
 limit given by [[sample_max_tries]] (user parameter), we can avoid an
 endless loop.
 
 NB: When reading from file, event transforms can't be applied because the
 process instance will not be complete.  This should be fixed.
 <<Simulations: simulation: TBP>>=
   procedure :: generate => simulation_generate
 <<Simulations: procedures>>=
   subroutine simulation_generate (simulation, n, es_array)
     class(simulation_t), intent(inout), target :: simulation
     integer, intent(in) :: n
     type(event_stream_array_t), intent(inout), optional :: es_array
     type(string_t) :: str1, str2, str3
     logical :: generate_new, passed
     integer :: i, j, k
     type(entry_t), pointer :: current_entry
     integer :: n_events
   <<Simulations: simulation generate: variables>>
     simulation%n_evt_requested = n
     n_events = n * simulation%get_n_nlo_entries (1)
     call simulation%entry%set_n (n)
     if (simulation%n_alt > 0)  call simulation%alt_entry%set_n (n)
     str1 = "Events: generating"
     if (present (es_array)) then
        if (es_array%has_input ())  str1 = "Events: reading"
     end if
     if (simulation%entry(1)%config%unweighted) then
        str2 = "unweighted"
     else
        str2 = "weighted"
     end if
     if (simulation%entry(1)%config%factorization_mode == &
          FM_IGNORE_HELICITY) then
        str3 = ", unpolarized"
     else
        str3 = ", polarized"
     end if
     if (n_events == n) then
        write (msg_buffer, "(A,1x,I0,1x,A,1x,A)")  char (str1), n, &
             char (str2) // char(str3), "events ..."
     else
        write (msg_buffer, "(A,1x,I0,1x,A,1x,A)") char (str1), n_events, &
             char (str2) // char(str3), "NLO events ..."
     end if
     call msg_message ()
     write (msg_buffer, "(A,1x,A)") "Events: event normalization mode", &
          char (event_normalization_string (simulation%norm_mode))
     call msg_message ()
     call simulation%init_event_index ()
   <<Simulations: simulation generate: init>>
     do i = start_it, end_it
        call simulation%increment_event_index ()
        if (present (es_array)) then
           call simulation%read_event (es_array, .true., generate_new)
        else
           generate_new = .true.
        end if
        if (generate_new) then
           simulation%i_prc = simulation%select_prc ()
           simulation%i_mci = simulation%select_mci ()
           associate (entry => simulation%entry(simulation%i_prc))
             entry%instance%i_mci = simulation%i_mci
             call entry%set_active_real_components ()
             current_entry => entry%get_first ()
             do k = 1, current_entry%count_nlo_entries ()
                if (k > 1) then
                   current_entry => current_entry%get_next ()
                   current_entry%particle_set => current_entry%first%particle_set
                   current_entry%particle_set_is_valid &
                      = current_entry%first%particle_set_is_valid
                end if
                do j = 1, simulation%n_max_tries
                   if (.not. current_entry%valid)  call msg_warning &
                           ("Process '" // char (current_entry%process_id) // "': " // &
                           "matrix element vanishes, no events can be generated.")
                   call current_entry%generate (simulation%i_mci, i_nlo = k)
                   if (signal_is_pending ()) return
                   call simulation%counter%record_mean_and_variance &
                        (current_entry%weight_prc, k)
                   if (current_entry%has_valid_particle_set ()) exit
                end do
             end do
             if (entry%is_nlo ()) call entry%reset_nlo_counter ()
             if (.not. entry%has_valid_particle_set ()) then
                write (msg_buffer, "(A,I0,A)")  "Simulation: failed to &
                     &generate valid event after ", &
                     simulation%n_max_tries, " tries (sample_max_tries)"
                call msg_fatal ()
             end if
             current_entry => entry%get_first ()
             do k = 1, current_entry%count_nlo_entries ()
                if (k > 1) current_entry => current_entry%get_next ()
                call current_entry%set_index (simulation%get_event_index ())
                call current_entry%evaluate_expressions ()
             end do
             if (signal_is_pending ()) return
             simulation%n_dropped = entry%get_n_dropped ()
             if (entry%passed_selection ()) then
                simulation%weight = entry%get_weight_ref ()
                simulation%excess = entry%get_excess_prc ()
             end if
             call simulation%counter%record &
                  (simulation%weight, simulation%excess, simulation%n_dropped)
             call entry%record (simulation%i_mci)
           end associate
        else
           associate (entry => simulation%entry(simulation%i_prc))
             call simulation%set_event_index (entry%get_index ())
             call entry%accept_sqme_ref ()
             call entry%accept_weight_ref ()
             call entry%check ()
             call entry%evaluate_expressions ()
             if (signal_is_pending ()) return
             simulation%n_dropped = entry%get_n_dropped ()
             if (entry%passed_selection ()) then
                simulation%weight = entry%get_weight_ref ()
                simulation%excess = entry%get_excess_prc ()
             end if
             call simulation%counter%record &
                  (simulation%weight, simulation%excess, simulation%n_dropped, from_file=.true.)
             call entry%record (simulation%i_mci, from_file=.true.)
           end associate
        end if
        call simulation%calculate_alt_entries ()
        if (signal_is_pending ()) return
        if (simulation%pacify)  call pacify (simulation)
        if (simulation%respect_selection) then
           passed = simulation%entry(simulation%i_prc)%passed_selection ()
        else
           passed = .true.
        end if
        if (present (es_array)) then
           call simulation%write_event (es_array, passed)
        end if
     end do
   <<Simulations: simulation generate: finalize>>
     call msg_message ("        ... event sample complete.")
     if (simulation%unweighted)  call simulation%show_efficiency ()
     call simulation%counter%show_excess ()
     call simulation%counter%show_dropped ()
     call simulation%counter%show_mean_and_variance ()
   end subroutine simulation_generate
 
 @ %def simulation_generate
 @
 <<Simulations: simulation generate: variables>>=
   integer :: start_it, end_it
 @
 <<Simulations: simulation generate: init>>=
   start_it = 1
   end_it = n
 @
 <<Simulations: simulation generate: finalize>>=
 @
 <<MPI: Simulations: simulation generate: variables>>=
   integer :: n_size, rank
   integer :: worker_n_events, root_n_events
 <<MPI: Simulations: simulation generate: init>>=
   call mpi_get_comm_id (n_size, rank)
   if (n_size > 1) then
      start_it = start_it + nint (rank * (real (n) / n_size))
      end_it = min (nint ((rank + 1) * (real (n) / n_size)), n)
      write (msg_buffer, "(A,I0,A,I0,A)") &
           & "MPI: generate events [", start_it, ":", end_it, "]"
      call msg_message ()
      do i = 1, rank + 1
         select type (rng => simulation%rng)
         type is (rng_stream_t)
            call rng%next_substream ()
         end select
      end do
   end if
 @
 <<MPI: Simulations: simulation generate: finalize>>=
   call MPI_Barrier (MPI_COMM_WORLD)
   if (n_size > 1) then
      worker_n_events = end_it - start_it + 1
      call MPI_Reduce (worker_n_events, root_n_events, 1, MPI_INTEGER, MPI_SUM,&
           & 0, MPI_COMM_WORLD)
      if (rank == 0) then
         write (msg_buffer, "(A,I0)") "MPI: Number of generated events in world = ", root_n_events
         call msg_message ()
      end if
   end if
 @
 @ Compute the event matrix element and weight for all alternative
 environments, given the current event and selected process.  We first
 copy the particle set, then temporarily update the process core with
 local parameters, recalculate everything, and restore the process
 core.
 
 The event weight is obtained by rescaling the original event weight with the
 ratio of the new and old [[sqme]] values.  (In particular, if the old
 value was zero, the weight will stay zero.)
 
 Note: this may turn out to be inefficient because we always replace
 all parameters and recalculate everything, once for each event and
 environment.  However, a more fine-grained control requires more
 code.  In any case, while we may keep multiple process cores (which
 stay constant for a simulation run), we still have to update the
 external matrix element parameters event by event.  The matrix element
 ``object'' is present only once.
 <<Simulations: simulation: TBP>>=
   procedure :: calculate_alt_entries => simulation_calculate_alt_entries
 <<Simulations: procedures>>=
   subroutine simulation_calculate_alt_entries (simulation)
     class(simulation_t), intent(inout) :: simulation
     real(default) :: factor
     real(default), dimension(:), allocatable :: sqme_alt, weight_alt
     integer :: n_alt, i, j
     i = simulation%i_prc
     n_alt = simulation%n_alt
     if (n_alt == 0)  return
     allocate (sqme_alt (n_alt), weight_alt (n_alt))
     associate (entry => simulation%entry(i))
       do j = 1, n_alt
          if (signal_is_pending ())  return
          factor = entry%get_kinematical_weight ()
          associate (alt_entry => simulation%alt_entry(i,j))
            call alt_entry%update_process ()
            call alt_entry%select &
                 (entry%get_i_mci (), entry%get_i_term (), entry%get_channel ())
            call alt_entry%fill_particle_set (entry)
            call alt_entry%recalculate &
                 (update_sqme = .true., weight_factor = factor)
            if (signal_is_pending ())  return
            call alt_entry%accept_sqme_prc ()
            call alt_entry%update_normalization ()
            call alt_entry%accept_weight_prc ()
            call alt_entry%check ()
            call alt_entry%set_index (simulation%get_event_index ())
            call alt_entry%evaluate_expressions ()
            if (signal_is_pending ())  return
            call alt_entry%restore_process ()
            sqme_alt(j) = alt_entry%get_sqme_ref ()
            if (alt_entry%passed_selection ()) then
               weight_alt(j) = alt_entry%get_weight_ref ()
            end if
          end associate
       end do
       call entry%set (sqme_alt = sqme_alt, weight_alt = weight_alt)
       call entry%check ()
       call entry%store_alt_values ()
     end associate
   end subroutine simulation_calculate_alt_entries
 
 @ %def simulation_calculate_alt_entries
 @ Rescan an undefined number of events.
 
 If [[update_event]] or [[update_sqme]] is set, we have to recalculate the
 event, starting from the particle set.  If the latter is set, this includes
 the squared matrix element (i.e., the amplitude is evaluated).  Otherwise,
 only kinematics and observables derived from it are recovered.
 
 If any of the update flags is set, we will come up with separate
 [[sqme_prc]] and [[weight_prc]] values.  (The latter is only distinct
 if [[update_weight]] is set.)  Otherwise, we accept the reference values.
 <<Simulations: simulation: TBP>>=
   procedure :: rescan => simulation_rescan
 <<Simulations: procedures>>=
   subroutine simulation_rescan (simulation, n, es_array, global)
     class(simulation_t), intent(inout) :: simulation
     integer, intent(in) :: n
     type(event_stream_array_t), intent(inout) :: es_array
     type(rt_data_t), intent(inout) :: global
     type(qcd_t) :: qcd
     type(string_t) :: str1, str2, str3
     logical :: complete
     str1 = "Rescanning"
     if (simulation%entry(1)%config%unweighted) then
        str2 = "unweighted"
     else
        str2 = "weighted"
     end if
     simulation%n_evt_requested = n
     call simulation%entry%set_n (n)
     if (simulation%update_sqme .or. simulation%update_weight) then
        call dispatch_qcd (qcd, global%get_var_list_ptr (), global%os_data)
        call simulation%update_processes &
             (global%model, qcd, global%get_helicity_selection ())
        str3 = "(process parameters updated) "
     else
        str3 = ""
     end if
     write (msg_buffer, "(A,1x,A,1x,A,A,A)")  char (str1), char (str2), &
          "events ", char (str3), "..."
     call msg_message ()
     call simulation%init_event_index ()
     do
        call simulation%increment_event_index ()
        call simulation%read_event (es_array, .false., complete)
        if (complete)  exit
        if (simulation%update_event &
             .or. simulation%update_sqme &
             .or. simulation%update_weight) then
           call simulation%recalculate ()
           if (signal_is_pending ())  return
           associate (entry => simulation%entry(simulation%i_prc))
             call entry%update_normalization ()
             if (simulation%update_event) then
                call entry%evaluate_transforms ()
             end if
             call entry%check ()
             call entry%evaluate_expressions ()
             if (signal_is_pending ())  return
             simulation%n_dropped = entry%get_n_dropped ()
             simulation%weight = entry%get_weight_prc ()
             call simulation%counter%record &
                  (simulation%weight, n_dropped=simulation%n_dropped, from_file=.true.)
             call entry%record (simulation%i_mci, from_file=.true.)
           end associate
        else
           associate (entry => simulation%entry(simulation%i_prc))
             call entry%accept_sqme_ref ()
             call entry%accept_weight_ref ()
             call entry%check ()
             call entry%evaluate_expressions ()
             if (signal_is_pending ())  return
             simulation%n_dropped = entry%get_n_dropped ()
             simulation%weight = entry%get_weight_ref ()
             call simulation%counter%record &
                  (simulation%weight, n_dropped=simulation%n_dropped, from_file=.true.)
             call entry%record (simulation%i_mci, from_file=.true.)
           end associate
        end if
        call simulation%calculate_alt_entries ()
        if (signal_is_pending ())  return
        call simulation%write_event (es_array)
     end do
     call simulation%counter%show_dropped ()
     if (simulation%update_sqme .or. simulation%update_weight) then
        call simulation%restore_processes ()
     end if
   end subroutine simulation_rescan
 
 @ %def simulation_rescan
 @ Here we handle the event index that is kept in the simulation record.  The
 event index is valid for the current sample.  When generating or reading
 events, we initialize the index with the offset that the user provides (if any)
 and increment it for each event that is generated or read from file.  The event
 index is stored in the event-entry that is current for the event.  If an
 event on file comes with its own index, that index overwrites the predefined
 one and also resets the index within the simulation record.
 
 The event index is not connected to the [[counter]] object.  The counter is
 supposed to collect statistical information.  The event index is a user-level
 object that is visible in event records and analysis expressions.
 <<Simulations: simulation: TBP>>=
   procedure :: init_event_index => simulation_init_event_index
   procedure :: increment_event_index => simulation_increment_event_index
   procedure :: set_event_index => simulation_set_event_index
   procedure :: get_event_index => simulation_get_event_index
 <<Simulations: procedures>>=
   subroutine simulation_init_event_index (simulation)
     class(simulation_t), intent(inout) :: simulation
     call simulation%set_event_index (simulation%event_index_offset)
   end subroutine simulation_init_event_index
 
   subroutine simulation_increment_event_index (simulation)
     class(simulation_t), intent(inout) :: simulation
     if (simulation%event_index_set) then
        simulation%event_index = simulation%event_index + 1
     end if
   end subroutine simulation_increment_event_index
 
   subroutine simulation_set_event_index (simulation, i)
     class(simulation_t), intent(inout) :: simulation
     integer, intent(in) :: i
     simulation%event_index = i
     simulation%event_index_set = .true.
   end subroutine simulation_set_event_index
 
   function simulation_get_event_index (simulation) result (i)
     class(simulation_t), intent(in) :: simulation
     integer :: i
     if (simulation%event_index_set) then
        i = simulation%event_index
     else
        i = 0
     end if
   end function simulation_get_event_index
 
 @ %def simulation_init_event_index
 @ %def simulation_increment_event_index
 @ %def simulation_set_event_index
 @ %def simulation_get_event_index
 @ 
 @ These routines take care of temporary parameter redefinitions that
 we want to take effect while recalculating the matrix elements.  We
 extract the core(s) of the processes that we are simulating, apply the
 changes, and make sure that the changes are actually used.  This is
 the duty of [[dispatch_core_update]].  When done, we restore the
 original versions using [[dispatch_core_restore]].
 <<Simulations: simulation: TBP>>=
   procedure :: update_processes => simulation_update_processes
   procedure :: restore_processes => simulation_restore_processes
 <<Simulations: procedures>>=
   subroutine simulation_update_processes (simulation, &
        model, qcd, helicity_selection)
     class(simulation_t), intent(inout) :: simulation
     class(model_data_t), intent(in), optional, target :: model
     type(qcd_t), intent(in), optional :: qcd
     type(helicity_selection_t), intent(in), optional :: helicity_selection
     integer :: i
     do i = 1, simulation%n_prc
        call simulation%entry(i)%update_process &
             (model, qcd, helicity_selection)
     end do
   end subroutine simulation_update_processes
 
   subroutine simulation_restore_processes (simulation)
     class(simulation_t), intent(inout) :: simulation
     integer :: i
     do i = 1, simulation%n_prc
        call simulation%entry(i)%restore_process ()
     end do
   end subroutine simulation_restore_processes
 
 @ %def simulation_update_processes
 @ %def simulation_restore_processes
 @
 \subsection{Event Stream I/O}
 Write an event to a generic [[eio]] event stream.  The process index
 must be selected, or the current index must be available.
 <<Simulations: simulation: TBP>>=
   generic :: write_event => write_event_eio
   procedure :: write_event_eio => simulation_write_event_eio
 <<Simulations: procedures>>=
   subroutine simulation_write_event_eio (object, eio, i_prc)
     class(simulation_t), intent(in) :: object
     class(eio_t), intent(inout) :: eio
     integer, intent(in), optional :: i_prc
     logical :: increased
     integer :: current
     if (present (i_prc)) then
        current = i_prc
     else
        current = object%i_prc
     end if
     if (current > 0) then
        if (object%split_n_evt > 0 .and. object%counter%total > 1) then
           if (mod (object%counter%total, object%split_n_evt) == 1) then
              call eio%split_out ()
           end if
        else if (object%split_n_kbytes > 0) then
           call eio%update_split_count (increased)
           if (increased)  call eio%split_out ()
        end if
        call eio%output (object%entry(current)%event_t, current, pacify = object%pacify)
     else
        call msg_fatal ("Simulation: write event: no process selected")
     end if
   end subroutine simulation_write_event_eio
 
 @ %def simulation_write_event
 @
 Read an event from a generic [[eio]] event stream.  The event stream element
 must specify the process within the sample ([[i_prc]]), the MC group for this
 process ([[i_mci]]), the selected term ([[i_term]]), the selected MC
 integration [[channel]], and the particle set of the event.
 
 We may encounter EOF, which we indicate by storing 0 for the process index
 [[i_prc]].  An I/O error will be reported, and we also abort reading.
 <<Simulations: simulation: TBP>>=
   generic :: read_event => read_event_eio
   procedure :: read_event_eio => simulation_read_event_eio
 <<Simulations: procedures>>=
   subroutine simulation_read_event_eio (object, eio)
     class(simulation_t), intent(inout) :: object
     class(eio_t), intent(inout) :: eio
     integer :: iostat, current
     call eio%input_i_prc (current, iostat)
     select case (iostat)
     case (0)
        object%i_prc = current
        call eio%input_event (object%entry(current)%event_t, iostat)
     end select
     select case (iostat)
     case (:-1)
        object%i_prc = 0
        object%i_mci = 0
     case (1:)
        call msg_error ("Reading events: I/O error, aborting read")
        object%i_prc = 0
        object%i_mci = 0
     case default
        object%i_mci = object%entry(current)%get_i_mci ()
     end select
   end subroutine simulation_read_event_eio
 
 @ %def simulation_read_event
 @
 \subsection{Event Stream Array}
 Write an event using an array of event I/O streams.
 The process index must be selected, or the current index must be
 available.
 <<Simulations: simulation: TBP>>=
   generic :: write_event => write_event_es_array
   procedure :: write_event_es_array => simulation_write_event_es_array
 <<Simulations: procedures>>=
   subroutine simulation_write_event_es_array (object, es_array, passed)
     class(simulation_t), intent(in), target :: object
     class(event_stream_array_t), intent(inout) :: es_array
     logical, intent(in), optional :: passed
     integer :: i_prc, event_index
     integer :: i
     type(entry_t), pointer :: current_entry
     i_prc = object%i_prc
     if (i_prc > 0) then
        event_index = object%counter%total
        current_entry => object%entry(i_prc)%get_first ()
        do i = 1, current_entry%count_nlo_entries ()
           if (i > 1) current_entry => current_entry%get_next ()
           call es_array%output (current_entry%event_t, i_prc, &
              event_index, passed = passed, pacify = object%pacify)
        end do
     else
        call msg_fatal ("Simulation: write event: no process selected")
     end if
   end subroutine simulation_write_event_es_array
 
 @ %def simulation_write_event
 @ Read an event using an array of event I/O streams.  Reading is
 successful if there is an input stream within the array, and if a
 valid event can be read from that stream.  If there is a stream, but
 EOF is passed when reading the first item, we switch the channel to
 output and return failure but no error message, such that new events
 can be appended to that stream.
 <<Simulations: simulation: TBP>>=
   generic :: read_event => read_event_es_array
   procedure :: read_event_es_array => simulation_read_event_es_array
 <<Simulations: procedures>>=
   subroutine simulation_read_event_es_array (object, es_array, enable_switch, &
        fail)
     class(simulation_t), intent(inout), target :: object
     class(event_stream_array_t), intent(inout), target :: es_array
     logical, intent(in) :: enable_switch
     logical, intent(out) :: fail
     integer :: iostat, i_prc
     type(entry_t), pointer :: current_entry => null ()
     integer :: i
     if (es_array%has_input ()) then
        fail = .false.
        call es_array%input_i_prc (i_prc, iostat)
        select case (iostat)
        case (0)
           object%i_prc = i_prc
           current_entry => object%entry(i_prc)
           do i = 1, current_entry%count_nlo_entries ()
              if (i > 1) then
                 call es_array%skip_eio_entry (iostat)
                 current_entry => current_entry%get_next ()
              end if
              call current_entry%set_index (object%get_event_index ())
              call es_array%input_event (current_entry%event_t, iostat)
           end do
        case (:-1)
           write (msg_buffer, "(A,1x,I0,1x,A)")  &
                "... event file terminates after", &
                object%counter%read, "events."
           call msg_message ()
           if (enable_switch) then
              call es_array%switch_inout ()
              write (msg_buffer, "(A,1x,I0,1x,A)")  &
                   "Generating remaining ", &
                   object%n_evt_requested - object%counter%read, "events ..."
              call msg_message ()
           end if
           fail = .true.
           return
        end select
        select case (iostat)
        case (0)
           object%i_mci = object%entry(i_prc)%get_i_mci ()
        case default
           write (msg_buffer, "(A,1x,I0,1x,A)")  &
                "Reading events: I/O error, aborting read after", &
                object%counter%read, "events."
           call msg_error ()
           object%i_prc = 0
           object%i_mci = 0
           fail = .true.
        end select
     else
        fail = .true.
     end if
   end subroutine simulation_read_event_es_array
 
 @ %def simulation_read_event
 @
 \subsection{Recover event}
 Recalculate the process instance contents, given an event with known particle
 set.  The indices for MC, term, and channel must be already set.  The
 [[recalculate]] method of the selected entry will import the result
 into [[sqme_prc]] and [[weight_prc]].
 
 If [[recover_phs]] is set (and false), do not attempt any phase-space
 calculation.  Useful if we need only matrix elements (esp. testing); this flag
 is not stored in the simulation record.
 <<Simulations: simulation: TBP>>=
   procedure :: recalculate => simulation_recalculate
 <<Simulations: procedures>>=
   subroutine simulation_recalculate (simulation, recover_phs)
     class(simulation_t), intent(inout) :: simulation
     logical, intent(in), optional :: recover_phs
     integer :: i_prc
     i_prc = simulation%i_prc
     associate (entry => simulation%entry(i_prc))
       if (simulation%update_weight) then
          call entry%recalculate &
               (update_sqme = simulation%update_sqme, &
               recover_beams = simulation%recover_beams, &
               recover_phs = recover_phs, &
               weight_factor = entry%get_kinematical_weight ())
       else
          call entry%recalculate &
               (update_sqme = simulation%update_sqme, &
               recover_beams = simulation%recover_beams, &
               recover_phs = recover_phs)
       end if
     end associate
   end subroutine simulation_recalculate
 
 @ %def simulation_recalculate
 @
 \subsection{Extract contents}
 Return the MD5 sum that summarizes configuration and integration
 (but not the event file).  Used for initializing the event streams.
 <<Simulations: simulation: TBP>>=
   procedure :: get_md5sum_prc => simulation_get_md5sum_prc
   procedure :: get_md5sum_cfg => simulation_get_md5sum_cfg
   procedure :: get_md5sum_alt => simulation_get_md5sum_alt
 <<Simulations: procedures>>=
   function simulation_get_md5sum_prc (simulation) result (md5sum)
     class(simulation_t), intent(in) :: simulation
     character(32) :: md5sum
     md5sum = simulation%md5sum_prc
   end function simulation_get_md5sum_prc
 
   function simulation_get_md5sum_cfg (simulation) result (md5sum)
     class(simulation_t), intent(in) :: simulation
     character(32) :: md5sum
     md5sum = simulation%md5sum_cfg
   end function simulation_get_md5sum_cfg
 
   function simulation_get_md5sum_alt (simulation, i) result (md5sum)
     class(simulation_t), intent(in) :: simulation
     integer, intent(in) :: i
     character(32) :: md5sum
     md5sum = simulation%md5sum_alt(i)
   end function simulation_get_md5sum_alt
 
 @ %def simulation_get_md5sum_prc
 @ %def simulation_get_md5sum_cfg
 @ Return data that may be useful for writing event files.
 
 Usually we can refer to a previously integrated process, for which we
 can fetch a process pointer.  Occasionally, we don't have this because
 we're just rescanning an externally generated file without
 calculation.  For that situation, we generate our local beam data object
 using the current enviroment, or, in simple cases, just fetch the
 necessary data from the process definition and environment.
 <<Simulations: simulation: TBP>>=
   procedure :: get_data => simulation_get_data
 <<Simulations: procedures>>=
   function simulation_get_data (simulation, alt) result (sdata)
     class(simulation_t), intent(in) :: simulation
     logical, intent(in), optional :: alt
     type(event_sample_data_t) :: sdata
     type(process_t), pointer :: process
     type(beam_data_t), pointer :: beam_data
     type(beam_structure_t), pointer :: beam_structure
     type(flavor_t), dimension(:), allocatable :: flv
     integer :: n, i
     logical :: enable_alt, construct_beam_data
     real(default) :: sqrts
     class(model_data_t), pointer :: model
     logical :: decay_rest_frame
     type(string_t) :: process_id
     enable_alt = .true.;  if (present (alt))  enable_alt = alt
     if (debug_on) call msg_debug (D_CORE, "simulation_get_data")
     if (debug_on) call msg_debug (D_CORE, "alternative setup", enable_alt)
     if (enable_alt) then
        call sdata%init (simulation%n_prc, simulation%n_alt)
        do i = 1, simulation%n_alt
           sdata%md5sum_alt(i) = simulation%get_md5sum_alt (i)
        end do
     else
        call sdata%init (simulation%n_prc)
     end if
     sdata%unweighted = simulation%unweighted
     sdata%negative_weights = simulation%negative_weights
     sdata%norm_mode = simulation%norm_mode
     process => simulation%entry(1)%get_process_ptr ()
     if (associated (process)) then
        beam_data => process%get_beam_data_ptr ()
        construct_beam_data = .false.
     else
        n = simulation%entry(1)%n_in
        sqrts = simulation%local%get_sqrts ()
        beam_structure => simulation%local%beam_structure
        call beam_structure%check_against_n_in (n, construct_beam_data)
        if (construct_beam_data) then
           allocate (beam_data)
           model => simulation%local%model
           decay_rest_frame = &
                simulation%local%get_lval (var_str ("?decay_rest_frame"))
           call beam_data%init_structure (beam_structure, &
                sqrts, model, decay_rest_frame)
        else
           beam_data => null ()
        end if
     end if
     if (associated (beam_data)) then
        n = beam_data%get_n_in ()
        sdata%n_beam = n
        allocate (flv (n))
        flv = beam_data%get_flavor ()
        sdata%pdg_beam(:n) = flv%get_pdg ()
        sdata%energy_beam(:n) = beam_data%get_energy ()
        if (construct_beam_data)  deallocate (beam_data)
     else
        n = simulation%entry(1)%n_in
        sdata%n_beam = n
        process_id = simulation%entry(1)%process_id
        call simulation%local%prclib%get_pdg_in_1 &
             (process_id, sdata%pdg_beam(:n))
        sdata%energy_beam(:n) = sqrts / n
     end if
     do i = 1, simulation%n_prc
        if (.not. simulation%entry(i)%valid) cycle
        process => simulation%entry(i)%get_process_ptr ()
        if (associated (process)) then
           sdata%proc_num_id(i) = process%get_num_id ()
        else
           process_id = simulation%entry(i)%process_id
           sdata%proc_num_id(i) = simulation%local%prclib%get_num_id (process_id)
        end if
        if (sdata%proc_num_id(i) == 0)  sdata%proc_num_id(i) = i
        if (simulation%entry(i)%has_integral) then
           sdata%cross_section(i) = simulation%entry(i)%integral
           sdata%error(i) = simulation%entry(i)%error
        end if
     end do
     sdata%total_cross_section = sum (sdata%cross_section)
     sdata%md5sum_prc = simulation%get_md5sum_prc ()
     sdata%md5sum_cfg = simulation%get_md5sum_cfg ()
     if (simulation%split_n_evt > 0 .or. simulation%split_n_kbytes > 0) then
        sdata%split_n_evt = simulation%split_n_evt
        sdata%split_n_kbytes = simulation%split_n_kbytes
        sdata%split_index = simulation%split_index
     end if
   end function simulation_get_data
 
 @ %def simulation_get_data
 @ Return a default name for the current event sample.  This is the
 process ID of the first process.
 <<Simulations: simulation: TBP>>=
   procedure :: get_default_sample_name => simulation_get_default_sample_name
 <<Simulations: procedures>>=
   function simulation_get_default_sample_name (simulation) result (sample)
     class(simulation_t), intent(in) :: simulation
     type(string_t) :: sample
     type(process_t), pointer :: process
     sample = "whizard"
     if (simulation%n_prc > 0) then
        process => simulation%entry(1)%get_process_ptr ()
        if (associated (process)) then
           sample = process%get_id ()
        end if
     end if
   end function simulation_get_default_sample_name
 
 @ %def simulation_get_default_sample_name
 @
 <<Simulations: simulation: TBP>>=
   procedure :: is_valid => simulation_is_valid
 <<Simulations: procedures>>=
   function simulation_is_valid (simulation) result (valid)
     class(simulation_t), intent(inout) :: simulation
     logical :: valid
     valid = simulation%valid
   end function simulation_is_valid
 
 @ %def simulation_is_valid
 @
 Return the hard-interaction particle set for event entry [[i_prc]].
 <<Simulations: simulation: TBP>>=
   procedure :: get_hard_particle_set => simulation_get_hard_particle_set
 <<Simulations: procedures>>=
   function simulation_get_hard_particle_set (simulation, i_prc) result (pset)
     class(simulation_t), intent(in) :: simulation
     integer, intent(in) :: i_prc
     type(particle_set_t) :: pset
     call simulation%entry(i_prc)%get_hard_particle_set (pset)
   end function simulation_get_hard_particle_set
 
 @ %def simulation_get_hard_particle_set
 @
 \subsection{Auxiliary}
 Call pacify: eliminate numerical noise.
 <<Simulations: public>>=
   public :: pacify
 <<Simulations: interfaces>>=
   interface pacify
      module procedure pacify_simulation
   end interface
 <<Simulations: procedures>>=
   subroutine pacify_simulation (simulation)
     class(simulation_t), intent(inout) :: simulation
     integer :: i, j
     i = simulation%i_prc
     if (i > 0) then
        call pacify (simulation%entry(i))
        do j = 1, simulation%n_alt
           call pacify (simulation%alt_entry(i,j))
        end do
     end if
   end subroutine pacify_simulation
 
 @ %def pacify_simulation
 @ Manually evaluate expressions for the currently selected process.
 This is used only in the unit tests.
 <<Simulations: simulation: TBP>>=
   procedure :: evaluate_expressions => simulation_evaluate_expressions
 <<Simulations: procedures>>=
   subroutine simulation_evaluate_expressions (simulation)
     class(simulation_t), intent(inout) :: simulation
     call simulation%entry(simulation%i_prc)%evaluate_expressions ()
   end subroutine simulation_evaluate_expressions
 
 @ %def simulation_evaluate_expressions
 @ Manually evaluate event transforms for the currently selected
 process.  This is used only in the unit tests.
 <<Simulations: simulation: TBP>>=
   procedure :: evaluate_transforms => simulation_evaluate_transforms
 <<Simulations: procedures>>=
   subroutine simulation_evaluate_transforms (simulation)
     class(simulation_t), intent(inout) :: simulation
     associate (entry => simulation%entry(simulation%i_prc))
       call entry%evaluate_transforms ()
     end associate
   end subroutine simulation_evaluate_transforms
 
 @ %def simulation_evaluate_transforms
 @
 \subsection{Unit tests}
 Test module, followed by the stand-alone unit-test procedures.
 <<[[simulations_ut.f90]]>>=
 <<File header>>
 
 module simulations_ut
   use unit_tests
   use simulations_uti
 
 <<Standard module head>>
 
 <<Simulations: public test>>
 
 contains
 
 <<Simulations: test driver>>
 
 end module simulations_ut
 @ %def simulations_ut
 @
 <<[[simulations_uti.f90]]>>=
 <<File header>>
 
 module simulations_uti
 
   <<Use kinds>>
     use kinds, only: i64
   <<Use strings>>
     use io_units
     use format_defs, only: FMT_10, FMT_12
     use ifiles
     use lexers
     use parser
     use lorentz
     use flavors
     use interactions, only: reset_interaction_counter
     use process_libraries, only: process_library_t
     use prclib_stacks
     use phs_forests
     use event_base, only: generic_event_t
     use event_base, only: event_callback_t
     use particles, only: particle_set_t
     use eio_data
     use eio_base
     use eio_direct, only: eio_direct_t
     use eio_raw
     use eio_ascii
     use eio_dump
     use eio_callback
     use eval_trees
     use model_data, only: model_data_t
     use models
     use rt_data
     use event_streams
     use decays_ut, only: prepare_testbed
     use process, only: process_t
     use process_stacks, only: process_entry_t
     use process_configurations_ut, only: prepare_test_library
     use compilations, only: compile_library
     use integrations, only: integrate_process
 
     use simulations
 
     use restricted_subprocesses_uti, only: prepare_resonance_test_library
 
 <<Standard module head>>
 
 <<Simulations: test declarations>>
 
 <<Simulations: test auxiliary types>>
 
 contains
 
 <<Simulations: tests>>
 
 <<Simulations: test auxiliary>>
 
 end module simulations_uti
 
 @ %def simulations_uti
 @ API: driver for the unit tests below.
 <<Simulations: public test>>=
   public :: simulations_test
 <<Simulations: test driver>>=
   subroutine simulations_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Simulations: execute tests>>
   end subroutine simulations_test
 
 @ %def simulations_test
 @
 \subsubsection{Initialization}
 Initialize a [[simulation_t]] object, including the embedded event records.
 <<Simulations: execute tests>>=
   call test (simulations_1, "simulations_1", &
        "initialization", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_1
 <<Simulations: tests>>=
   subroutine simulations_1 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1, procname2
     type(rt_data_t), target :: global
     type(simulation_t), target :: simulation
 
     write (u, "(A)")  "* Test output: simulations_1"
     write (u, "(A)")  "*   Purpose: initialize simulation"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize processes"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_1a"
     procname1 = "simulation_1p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("simulations1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     procname2 = "sim_extra"
 
     call prepare_test_library (global, libname, 1, [procname2])
     call compile_library (libname, global)
     call global%set_string (var_str ("$run_id"), &
          var_str ("simulations2"), is_known = .true.)
 
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call global%set_string (var_str ("$sample"), &
          var_str ("sim1"), is_known = .true.)
     call integrate_process (procname2, global, local_stack=.true.)
 
     call simulation%init ([procname1, procname2], .false., .true., global)
     call simulation%init_process_selector ()
     call simulation%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write the event record for the first process"
     write (u, "(A)")
 
     call simulation%write_event (u, i_prc = 1)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_1"
 
   end subroutine simulations_1
 
 @ %def simulations_1
 @
 \subsubsection{Weighted events}
 Generate events for a single process.
 <<Simulations: execute tests>>=
   call test (simulations_2, "simulations_2", &
        "weighted events", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_2
 <<Simulations: tests>>=
   subroutine simulations_2 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1
     type(rt_data_t), target :: global
     type(simulation_t), target :: simulation
     type(event_sample_data_t) :: data
 
     write (u, "(A)")  "* Test output: simulations_2"
     write (u, "(A)")  "*   Purpose: generate events for a single process"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize processes"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_2a"
     procname1 = "simulation_2p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("simulations1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     data = simulation%get_data ()
     call data%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Generate three events"
     write (u, "(A)")
 
     call simulation%generate (3)
     call simulation%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write the event record for the last event"
     write (u, "(A)")
 
     call simulation%write_event (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_2"
 
   end subroutine simulations_2
 
 @ %def simulations_2
 @
 \subsubsection{Unweighted events}
 Generate events for a single process.
 <<Simulations: execute tests>>=
   call test (simulations_3, "simulations_3", &
        "unweighted events", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_3
 <<Simulations: tests>>=
   subroutine simulations_3 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1
     type(rt_data_t), target :: global
     type(simulation_t), target :: simulation
     type(event_sample_data_t) :: data
 
     write (u, "(A)")  "* Test output: simulations_3"
     write (u, "(A)")  "*   Purpose: generate unweighted events &
          &for a single process"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize processes"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_3a"
     procname1 = "simulation_3p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("simulations1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     data = simulation%get_data ()
     call data%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Generate three events"
     write (u, "(A)")
 
     call simulation%generate (3)
     call simulation%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write the event record for the last event"
     write (u, "(A)")
 
     call simulation%write_event (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_3"
 
   end subroutine simulations_3
 
 @ %def simulations_3
 @
 \subsubsection{Simulating process with structure functions}
 Generate events for a single process.
 <<Simulations: execute tests>>=
   call test (simulations_4, "simulations_4", &
        "process with structure functions", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_4
 <<Simulations: tests>>=
   subroutine simulations_4 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1
     type(rt_data_t), target :: global
     type(flavor_t) :: flv
     type(string_t) :: name
     type(simulation_t), target :: simulation
     type(event_sample_data_t) :: data
 
     write (u, "(A)")  "* Test output: simulations_4"
     write (u, "(A)")  "*   Purpose: generate events for a single process &
          &with structure functions"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize processes"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_4a"
     procname1 = "simulation_4p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("wood"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .true., is_known = .true.)
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%model_set_real (var_str ("ms"), &
          0._default)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call reset_interaction_counter ()
 
     call flv%init (25, global%model)
     name = flv%get_name ()
 
     call global%beam_structure%init_sf ([name, name], [1])
     call global%beam_structure%set_sf (1, 1, var_str ("sf_test_1"))
 
     write (u, "(A)")  "* Integrate"
     write (u, "(A)")
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     call global%set_string (var_str ("$sample"), &
          var_str ("simulations4"), is_known = .true.)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     data = simulation%get_data ()
     call data%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Generate three events"
     write (u, "(A)")
 
     call simulation%generate (3)
     call simulation%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write the event record for the last event"
     write (u, "(A)")
 
     call simulation%write_event (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_4"
 
   end subroutine simulations_4
 
 @ %def simulations_4
 @
 \subsubsection{Event I/O}
 Generate event for a test process, write to file and reread.
 <<Simulations: execute tests>>=
   call test (simulations_5, "simulations_5", &
        "raw event I/O", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_5
 <<Simulations: tests>>=
   subroutine simulations_5 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1, sample
     type(rt_data_t), target :: global
     class(eio_t), allocatable :: eio
     type(simulation_t), allocatable, target :: simulation
 
     write (u, "(A)")  "* Test output: simulations_5"
     write (u, "(A)")  "*   Purpose: generate events for a single process"
     write (u, "(A)")  "*            write to file and reread"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize processes"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_5a"
     procname1 = "simulation_5p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("simulations5"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     sample = "simulations5"
     call global%set_string (var_str ("$sample"), &
          sample, is_known = .true.)
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     write (u, "(A)")  "* Initialize raw event file"
     write (u, "(A)")
 
     allocate (eio_raw_t :: eio)
     call eio%init_out (sample)
 
     write (u, "(A)")  "* Generate an event"
     write (u, "(A)")
 
     call simulation%generate (1)
     call simulation%write_event (u)
     call simulation%write_event (eio)
 
     call eio%final ()
     deallocate (eio)
     call simulation%final ()
     deallocate (simulation)
 
     write (u, "(A)")
     write (u, "(A)")  "* Re-read the event from file"
     write (u, "(A)")
 
     call global%set_log (var_str ("?update_sqme"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?update_weight"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
     allocate (eio_raw_t :: eio)
     call eio%init_in (sample)
 
     call simulation%read_event (eio)
     call simulation%write_event (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Recalculate process instance"
     write (u, "(A)")
 
     call simulation%recalculate ()
     call simulation%evaluate_expressions ()
     call simulation%write_event (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call eio%final ()
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_5"
 
   end subroutine simulations_5
 
 @ %def simulations_5
 @
 \subsubsection{Event I/O}
 Generate event for a real process with structure functions, write to file and
 reread.
 <<Simulations: execute tests>>=
   call test (simulations_6, "simulations_6", &
        "raw event I/O with structure functions", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_6
 <<Simulations: tests>>=
   subroutine simulations_6 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1, sample
     type(rt_data_t), target :: global
     class(eio_t), allocatable :: eio
     type(simulation_t), allocatable, target :: simulation
     type(flavor_t) :: flv
     type(string_t) :: name
 
     write (u, "(A)")  "* Test output: simulations_6"
     write (u, "(A)")  "*   Purpose: generate events for a single process"
     write (u, "(A)")  "*            write to file and reread"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and integrate"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_6"
     procname1 = "simulation_6p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("wood"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .true., is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%model_set_real (var_str ("ms"), &
          0._default)
 
     call flv%init (25, global%model)
     name = flv%get_name ()
 
     call global%beam_structure%init_sf ([name, name], [1])
     call global%beam_structure%set_sf (1, 1, var_str ("sf_test_1"))
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call reset_interaction_counter ()
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     sample = "simulations6"
     call global%set_string (var_str ("$sample"), &
          sample, is_known = .true.)
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     write (u, "(A)")  "* Initialize raw event file"
     write (u, "(A)")
 
     allocate (eio_raw_t :: eio)
     call eio%init_out (sample)
 
     write (u, "(A)")  "* Generate an event"
     write (u, "(A)")
 
     call simulation%generate (1)
     call pacify (simulation)
     call simulation%write_event (u, verbose = .true., testflag = .true.)
     call simulation%write_event (eio)
 
     call eio%final ()
     deallocate (eio)
     call simulation%final ()
     deallocate (simulation)
 
     write (u, "(A)")
     write (u, "(A)")  "* Re-read the event from file"
     write (u, "(A)")
 
     call reset_interaction_counter ()
 
     call global%set_log (var_str ("?update_sqme"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?update_weight"), &
          .true., is_known = .true.)
 
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
     allocate (eio_raw_t :: eio)
     call eio%init_in (sample)
 
     call simulation%read_event (eio)
     call simulation%write_event (u, verbose = .true., testflag = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Recalculate process instance"
     write (u, "(A)")
 
     call simulation%recalculate ()
     call simulation%evaluate_expressions ()
     call simulation%write_event (u, verbose = .true., testflag = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call eio%final ()
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_6"
 
   end subroutine simulations_6
 
 @ %def simulations_6
 @
 \subsubsection{Automatic Event I/O}
 Generate events with raw-format event file as cache: generate, reread,
 append.
 <<Simulations: execute tests>>=
   call test (simulations_7, "simulations_7", &
        "automatic raw event I/O", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_7
 <<Simulations: tests>>=
   subroutine simulations_7 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1, sample
     type(rt_data_t), target :: global
     type(string_t), dimension(0) :: empty_string_array
     type(event_sample_data_t) :: data
     type(event_stream_array_t) :: es_array
     type(simulation_t), allocatable, target :: simulation
     type(flavor_t) :: flv
     type(string_t) :: name
 
     write (u, "(A)")  "* Test output: simulations_7"
     write (u, "(A)")  "*   Purpose: generate events for a single process"
     write (u, "(A)")  "*            write to file and reread"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and integrate"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_7"
     procname1 = "simulation_7p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("wood"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .true., is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%model_set_real (var_str ("ms"), &
          0._default)
 
     call flv%init (25, global%model)
     name = flv%get_name ()
 
     call global%beam_structure%init_sf ([name, name], [1])
     call global%beam_structure%set_sf (1, 1, var_str ("sf_test_1"))
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call reset_interaction_counter ()
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     sample = "simulations7"
     call global%set_string (var_str ("$sample"), &
          sample, is_known = .true.)
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     write (u, "(A)")  "* Initialize raw event file"
     write (u, "(A)")
 
     data%md5sum_prc = simulation%get_md5sum_prc ()
     data%md5sum_cfg = simulation%get_md5sum_cfg ()
     call es_array%init (sample, [var_str ("raw")], global, data)
 
     write (u, "(A)")  "* Generate an event"
     write (u, "(A)")
 
     call simulation%generate (1, es_array)
 
     call es_array%final ()
     call simulation%final ()
     deallocate (simulation)
 
     write (u, "(A)")  "* Re-read the event from file and generate another one"
     write (u, "(A)")
 
     call global%set_log (&
          var_str ("?rebuild_events"), .false., is_known = .true.)
 
     call reset_interaction_counter ()
 
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     data%md5sum_prc = simulation%get_md5sum_prc ()
     data%md5sum_cfg = simulation%get_md5sum_cfg ()
     call es_array%init (sample, empty_string_array, global, data, &
          input = var_str ("raw"))
 
     call simulation%generate (2, es_array)
 
     call pacify (simulation)
     call simulation%write_event (u, verbose = .true.)
 
     call es_array%final ()
     call simulation%final ()
     deallocate (simulation)
 
 
     write (u, "(A)")
     write (u, "(A)")  "* Re-read both events from file"
     write (u, "(A)")
 
     call reset_interaction_counter ()
 
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     data%md5sum_prc = simulation%get_md5sum_prc ()
     data%md5sum_cfg = simulation%get_md5sum_cfg ()
     call es_array%init (sample, empty_string_array, global, data, &
          input = var_str ("raw"))
 
     call simulation%generate (2, es_array)
 
     call pacify (simulation)
     call simulation%write_event (u, verbose = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call es_array%final ()
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_7"
 
   end subroutine simulations_7
 
 @ %def simulations_7
 @
 \subsubsection{Rescanning Events}
 Generate events and rescan the resulting raw event file.
 <<Simulations: execute tests>>=
   call test (simulations_8, "simulations_8", &
        "rescan raw event file", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_8
 <<Simulations: tests>>=
   subroutine simulations_8 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1, sample
     type(rt_data_t), target :: global
     type(string_t), dimension(0) :: empty_string_array
     type(event_sample_data_t) :: data
     type(event_stream_array_t) :: es_array
     type(simulation_t), allocatable, target :: simulation
     type(flavor_t) :: flv
     type(string_t) :: name
 
     write (u, "(A)")  "* Test output: simulations_8"
     write (u, "(A)")  "*   Purpose: generate events for a single process"
     write (u, "(A)")  "*            write to file and rescan"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and integrate"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_8"
     procname1 = "simulation_8p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("wood"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .true., is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%model_set_real (var_str ("ms"), &
          0._default)
 
     call flv%init (25, global%model)
     name = flv%get_name ()
 
     call global%beam_structure%init_sf ([name, name], [1])
     call global%beam_structure%set_sf (1, 1, var_str ("sf_test_1"))
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call reset_interaction_counter ()
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     sample = "simulations8"
     call global%set_string (var_str ("$sample"), &
          sample, is_known = .true.)
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     write (u, "(A)")  "* Initialize raw event file"
     write (u, "(A)")
 
     data%md5sum_prc = simulation%get_md5sum_prc ()
     data%md5sum_cfg = simulation%get_md5sum_cfg ()
     write (u, "(1x,A,A,A)")  "MD5 sum (proc)   = '", data%md5sum_prc, "'"
     write (u, "(1x,A,A,A)")  "MD5 sum (config) = '", data%md5sum_cfg, "'"
     call es_array%init (sample, [var_str ("raw")], global, &
          data)
 
     write (u, "(A)")
     write (u, "(A)")  "* Generate an event"
     write (u, "(A)")
 
     call simulation%generate (1, es_array)
 
     call pacify (simulation)
     call simulation%write_event (u, verbose = .true., testflag = .true.)
 
     call es_array%final ()
     call simulation%final ()
     deallocate (simulation)
 
     write (u, "(A)")
     write (u, "(A)")  "* Re-read the event from file"
     write (u, "(A)")
 
     call reset_interaction_counter ()
 
     allocate (simulation)
     call simulation%init ([procname1], .false., .false., global)
     call simulation%init_process_selector ()
 
     data%md5sum_prc = simulation%get_md5sum_prc ()
     data%md5sum_cfg = ""
     write (u, "(1x,A,A,A)")  "MD5 sum (proc)   = '", data%md5sum_prc, "'"
     write (u, "(1x,A,A,A)")  "MD5 sum (config) = '", data%md5sum_cfg, "'"
     call es_array%init (sample, empty_string_array, global, data, &
          input = var_str ("raw"), input_sample = sample, allow_switch = .false.)
 
     call simulation%rescan (1, es_array, global = global)
 
     write (u, "(A)")
 
     call pacify (simulation)
     call simulation%write_event (u, verbose = .true., testflag = .true.)
 
     call es_array%final ()
     call simulation%final ()
     deallocate (simulation)
 
     write (u, "(A)")
     write (u, "(A)")  "* Re-read again and recalculate"
     write (u, "(A)")
 
     call reset_interaction_counter ()
 
     call global%set_log (var_str ("?update_sqme"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?update_event"), &
          .true., is_known = .true.)
 
     allocate (simulation)
     call simulation%init ([procname1], .false., .false., global)
     call simulation%init_process_selector ()
 
     data%md5sum_prc = simulation%get_md5sum_prc ()
     data%md5sum_cfg = ""
     write (u, "(1x,A,A,A)")  "MD5 sum (proc)   = '", data%md5sum_prc, "'"
     write (u, "(1x,A,A,A)")  "MD5 sum (config) = '", data%md5sum_cfg, "'"
     call es_array%init (sample, empty_string_array, global, data, &
          input = var_str ("raw"), input_sample = sample, allow_switch = .false.)
 
     call simulation%rescan (1, es_array, global = global)
 
     write (u, "(A)")
 
     call pacify (simulation)
     call simulation%write_event (u, verbose = .true., testflag = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call es_array%final ()
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_8"
 
   end subroutine simulations_8
 
 @ %def simulations_8
 @
 \subsubsection{Rescanning Check}
 Generate events and rescan with process mismatch.
 <<Simulations: execute tests>>=
   call test (simulations_9, "simulations_9", &
        "rescan mismatch", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_9
 <<Simulations: tests>>=
   subroutine simulations_9 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1, sample
     type(rt_data_t), target :: global
     type(string_t), dimension(0) :: empty_string_array
     type(event_sample_data_t) :: data
     type(event_stream_array_t) :: es_array
     type(simulation_t), allocatable, target :: simulation
     type(flavor_t) :: flv
     type(string_t) :: name
     logical :: error
 
     write (u, "(A)")  "* Test output: simulations_9"
     write (u, "(A)")  "*   Purpose: generate events for a single process"
     write (u, "(A)")  "*            write to file and rescan"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and integrate"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_9"
     procname1 = "simulation_9p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("wood"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("vamp"), is_known = .true.)
     call global%set_log (var_str ("?use_vamp_equivalences"),&
          .true., is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%model_set_real (var_str ("ms"), &
          0._default)
 
     call flv%init (25, global%model)
     name = flv%get_name ()
 
     call global%beam_structure%init_sf ([name, name], [1])
     call global%beam_structure%set_sf (1, 1, var_str ("sf_test_1"))
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call reset_interaction_counter ()
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     sample = "simulations9"
     call global%set_string (var_str ("$sample"), &
          sample, is_known = .true.)
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     call simulation%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize raw event file"
     write (u, "(A)")
 
     data%md5sum_prc = simulation%get_md5sum_prc ()
     data%md5sum_cfg = simulation%get_md5sum_cfg ()
     write (u, "(1x,A,A,A)")  "MD5 sum (proc)   = '", data%md5sum_prc, "'"
     write (u, "(1x,A,A,A)")  "MD5 sum (config) = '", data%md5sum_cfg, "'"
     call es_array%init (sample, [var_str ("raw")], global, &
          data)
 
     write (u, "(A)")
     write (u, "(A)")  "* Generate an event"
     write (u, "(A)")
 
     call simulation%generate (1, es_array)
 
     call es_array%final ()
     call simulation%final ()
     deallocate (simulation)
 
     write (u, "(A)")  "* Initialize event generation for different parameters"
     write (u, "(A)")
 
     call reset_interaction_counter ()
 
     allocate (simulation)
     call simulation%init ([procname1, procname1], .false., .false., global)
     call simulation%init_process_selector ()
 
     call simulation%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Attempt to re-read the events (should fail)"
     write (u, "(A)")
 
     data%md5sum_prc = simulation%get_md5sum_prc ()
     data%md5sum_cfg = ""
     write (u, "(1x,A,A,A)")  "MD5 sum (proc)   = '", data%md5sum_prc, "'"
     write (u, "(1x,A,A,A)")  "MD5 sum (config) = '", data%md5sum_cfg, "'"
     call es_array%init (sample, empty_string_array, global, data, &
          input = var_str ("raw"), input_sample = sample, &
          allow_switch = .false., error = error)
 
     write (u, "(1x,A,L1)")  "error = ", error
 
     call simulation%rescan (1, es_array, global = global)
 
     call es_array%final ()
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_9"
 
   end subroutine simulations_9
 
 @ %def simulations_9
 @
 \subsubsection{Alternative weights}
 Generate an event for a single process and reweight it in a
 simultaneous calculation.
 <<Simulations: execute tests>>=
   call test (simulations_10, "simulations_10", &
        "alternative weight", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_10
 <<Simulations: tests>>=
   subroutine simulations_10 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1, expr_text
     type(rt_data_t), target :: global
     type(rt_data_t), dimension(1), target :: alt_env
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: pt_weight
     type(simulation_t), target :: simulation
     type(event_sample_data_t) :: data
 
     write (u, "(A)")  "* Test output: simulations_10"
     write (u, "(A)")  "*   Purpose: reweight event"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize processes"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_pexpr_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_10a"
     procname1 = "simulation_10p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("simulations1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize alternative environment with custom weight"
     write (u, "(A)")
 
     call alt_env(1)%local_init (global)
     call alt_env(1)%activate ()
 
     expr_text = "2"
     write (u, "(A,A)")  "weight = ", char (expr_text)
     write (u, *)
 
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_weight, stream, .true.)
     call stream_final (stream)
     alt_env(1)%pn%weight_expr => pt_weight%get_root_ptr ()
     call alt_env(1)%write_expr (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     call simulation%init ([procname1], .true., .true., global, alt_env=alt_env)
     call simulation%init_process_selector ()
 
     data = simulation%get_data ()
     call data%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Generate an event"
     write (u, "(A)")
 
     call simulation%generate (1)
     call simulation%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write the event record for the last event"
     write (u, "(A)")
 
     call simulation%write_event (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write the event record for the alternative setup"
     write (u, "(A)")
 
     call simulation%write_alt_event (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call simulation%final ()
     call global%final ()
 
     call syntax_model_file_final ()
     call syntax_pexpr_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_10"
 
   end subroutine simulations_10
 
 @ %def simulations_10
 @
 \subsubsection{Decays}
 Generate an event with subsequent partonic decays.
 <<Simulations: execute tests>>=
   call test (simulations_11, "simulations_11", &
        "decay", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_11
 <<Simulations: tests>>=
   subroutine simulations_11 (u)
     integer, intent(in) :: u
     type(rt_data_t), target :: global
     type(prclib_entry_t), pointer :: lib
     type(string_t) :: prefix, procname1, procname2
     type(simulation_t), target :: simulation
 
     write (u, "(A)")  "* Test output: simulations_11"
     write (u, "(A)")  "*   Purpose: apply decay"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize processes"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     allocate (lib)
     call global%add_prclib (lib)
 
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     prefix = "simulation_11"
     procname1 = prefix // "_p"
     procname2 = prefix // "_d"
     call prepare_testbed &
          (global%prclib, global%process_stack, &
          prefix, global%os_data, &
          scattering=.true., decay=.true.)
 
     call global%select_model (var_str ("Test"))
     call global%model%set_par (var_str ("ff"), 0.4_default)
     call global%model%set_par (var_str ("mf"), &
          global%model%get_real (var_str ("ff")) &
          * global%model%get_real (var_str ("ms")))
     call global%model%set_unstable (25, [procname2])
 
     write (u, "(A)")  "* Initialize simulation object"
     write (u, "(A)")
 
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     write (u, "(A)")  "* Generate event"
     write (u, "(A)")
 
     call simulation%generate (1)
     call simulation%write (u)
 
     write (u, *)
 
     call simulation%write_event (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
     write (u, "(A)")
 
     call simulation%final ()
     call global%final ()
 
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_11"
 
   end subroutine simulations_11
 
 @ %def simulations_11
 @
 \subsubsection{Split Event Files}
 Generate event for a real process with structure functions and write to file,
 accepting a limit for the number of events per file.
 <<Simulations: execute tests>>=
   call test (simulations_12, "simulations_12", &
        "split event files", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_12
 <<Simulations: tests>>=
   subroutine simulations_12 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1, sample
     type(rt_data_t), target :: global
     class(eio_t), allocatable :: eio
     type(simulation_t), allocatable, target :: simulation
     type(flavor_t) :: flv
     integer :: i_evt
 
     write (u, "(A)")  "* Test output: simulations_12"
     write (u, "(A)")  "*   Purpose: generate events for a single process"
     write (u, "(A)")  "*            and write to split event files"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and integrate"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_12"
     procname1 = "simulation_12p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%model_set_real (var_str ("ms"), &
          0._default)
 
     call flv%init (25, global%model)
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     sample = "simulations_12"
     call global%set_string (var_str ("$sample"), &
          sample, is_known = .true.)
     call global%set_int (var_str ("sample_split_n_evt"), &
          2, is_known = .true.)
     call global%set_int (var_str ("sample_split_index"), &
          42, is_known = .true.)
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     call simulation%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize ASCII event file"
     write (u, "(A)")
 
     allocate (eio_ascii_short_t :: eio)
     select type (eio)
     class is (eio_ascii_t);  call eio%set_parameters ()
     end select
     call eio%init_out (sample, data = simulation%get_data ())
 
     write (u, "(A)")  "* Generate 5 events, distributed among three files"
 
     do i_evt = 1, 5
        call simulation%generate (1)
        call simulation%write_event (eio)
     end do
 
     call eio%final ()
     deallocate (eio)
     call simulation%final ()
     deallocate (simulation)
 
     write (u, *)
     call display_file ("simulations_12.42.short.evt", u)
     write (u, *)
     call display_file ("simulations_12.43.short.evt", u)
     write (u, *)
     call display_file ("simulations_12.44.short.evt", u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_12"
 
   end subroutine simulations_12
 
 @ %def simulations_12
 @ Auxiliary: display file contents.
 <<Simulations: public test auxiliary>>=
   public :: display_file
 <<Simulations: test auxiliary>>=
   subroutine display_file (file, u)
     use io_units, only: free_unit
     character(*), intent(in) :: file
     integer, intent(in) :: u
     character(256) :: buffer
     integer :: u_file
     write (u, "(3A)")  "* Contents of file '", file, "':"
     write (u, *)
     u_file = free_unit ()
     open (u_file, file = file, action = "read", status = "old")
     do
        read (u_file, "(A)", end = 1)  buffer
        write (u, "(A)")  trim (buffer)
     end do
 1   continue
   end subroutine display_file
 
 @ %def display_file
 @
 \subsubsection{Callback}
 Generate events and execute a callback in place of event I/O.
 <<Simulations: execute tests>>=
   call test (simulations_13, "simulations_13", &
        "callback", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_13
 <<Simulations: tests>>=
   subroutine simulations_13 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, procname1, sample
     type(rt_data_t), target :: global
     class(eio_t), allocatable :: eio
     type(simulation_t), allocatable, target :: simulation
     type(flavor_t) :: flv
     integer :: i_evt
     type(simulations_13_callback_t) :: event_callback
 
     write (u, "(A)")  "* Test output: simulations_13"
     write (u, "(A)")  "*   Purpose: generate events for a single process"
     write (u, "(A)")  "*            and execute callback"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialize process and integrate"
     write (u, "(A)")
 
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
 
     libname = "simulation_13"
     procname1 = "simulation_13p"
 
     call prepare_test_library (global, libname, 1, [procname1])
     call compile_library (libname, global)
 
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
 
     call global%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known = .true.)
     call global%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known = .true.)
     call global%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known = .true.)
     call global%set_log (var_str ("?vis_history"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
 
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
 
     call flv%init (25, global%model)
 
     call global%it_list%init ([1], [1000])
 
     call global%set_string (var_str ("$run_id"), &
          var_str ("r1"), is_known = .true.)
     call integrate_process (procname1, global, local_stack=.true.)
 
     write (u, "(A)")  "* Initialize event generation"
     write (u, "(A)")
 
     call global%set_log (var_str ("?unweighted"), &
          .false., is_known = .true.)
     sample = "simulations_13"
     call global%set_string (var_str ("$sample"), &
          sample, is_known = .true.)
 
     allocate (simulation)
     call simulation%init ([procname1], .true., .true., global)
     call simulation%init_process_selector ()
 
     write (u, "(A)")  "* Prepare callback object"
     write (u, "(A)")
 
     event_callback%u = u
     call global%set_event_callback (event_callback)
 
     write (u, "(A)")  "* Initialize callback I/O object"
     write (u, "(A)")
 
     allocate (eio_callback_t :: eio)
     select type (eio)
     class is (eio_callback_t)
        call eio%set_parameters (callback = event_callback, &
             count_interval = 3)
     end select
     call eio%init_out (sample, data = simulation%get_data ())
 
     write (u, "(A)")  "* Generate 7 events, with callback every 3 events"
     write (u, "(A)")
 
     do i_evt = 1, 7
        call simulation%generate (1)
        call simulation%write_event (eio)
     end do
 
     call eio%final ()
     deallocate (eio)
     call simulation%final ()
     deallocate (simulation)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_13"
 
   end subroutine simulations_13
 
 @ %def simulations_13
 @ The callback object and procedure.  In the type extension, we can
 store the output channel [[u]] so we know where to write into.
 <<Simulations: test auxiliary types>>=
   type, extends (event_callback_t) :: simulations_13_callback_t
      integer :: u
    contains
      procedure :: write => simulations_13_callback_write
      procedure :: proc => simulations_13_callback
   end type simulations_13_callback_t
 
 @ %def simulations_13_callback_t
 <<Simulations: test auxiliary>>=
   subroutine simulations_13_callback_write (event_callback, unit)
     class(simulations_13_callback_t), intent(in) :: event_callback
     integer, intent(in), optional :: unit
     integer :: u
     u = given_output_unit (unit)
     write (u, "(1x,A)")  "Hello"
   end subroutine simulations_13_callback_write
 
   subroutine simulations_13_callback (event_callback, i, event)
     class(simulations_13_callback_t), intent(in) :: event_callback
     integer(i64), intent(in) :: i
     class(generic_event_t), intent(in) :: event
     write (event_callback%u, "(A,I0)")  "hello event #", i
   end subroutine simulations_13_callback
 
 @ %def simulations_13_callback_write
 @ %def simulations_13_callback
 @
 \subsubsection{Resonant subprocess setup}
 Prepare a process with resonances and enter resonant subprocesses in
 the simulation object.  Select a kinematics configuration and compute
 probabilities for resonant subprocesses.
 
 The process and its initialization is taken from [[processes_18]], but
 we need a complete \oMega\ matrix element here.
 <<Simulations: execute tests>>=
   call test (simulations_14, "simulations_14", &
        "resonant subprocesses evaluation", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_14
 <<Simulations: tests>>=
   subroutine simulations_14 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, libname_generated
     type(string_t) :: procname
     type(string_t) :: model_name
     type(rt_data_t), target :: global
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     class(model_t), pointer :: model
     class(model_data_t), pointer :: model_data
     type(simulation_t), target :: simulation
     type(particle_set_t) :: pset
     type(eio_direct_t) :: eio_in
     type(eio_dump_t) :: eio_out
     real(default) :: sqrts, mw, pp
     real(default), dimension(3) :: p3
     type(vector4_t), dimension(:), allocatable :: p
     real(default), dimension(:), allocatable :: m
     integer :: u_verbose, i
     real(default) :: sqme_proc
     real(default), dimension(:), allocatable :: sqme
     real(default) :: on_shell_limit
     integer, dimension(:), allocatable :: i_array
     real(default), dimension(:), allocatable :: prob_array
 
     write (u, "(A)")  "* Test output: simulations_14"
     write (u, "(A)")  "*   Purpose: construct resonant subprocesses &
          &in the simulation object"
     write (u, "(A)")
 
     write (u, "(A)")  "* Build and load a test library with one process"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     libname = "simulations_14_lib"
     procname = "simulations_14_p"
 
     call global%global_init ()
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
     call global%set_log (var_str ("?update_sqme"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?update_weight"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?update_event"), &
          .true., is_known = .true.)
 
     model_name = "SM"
     call global%select_model (model_name)
     allocate (model)
     call model%init_instance (global%model)
     model_data => model
 
     write (u, "(A)")  "* Initialize process library and process"
     write (u, "(A)")
 
     allocate (lib_entry)
     call lib_entry%init (libname)
     lib => lib_entry%process_library_t
     call global%add_prclib (lib_entry)
 
     call prepare_resonance_test_library &
          (lib, libname, procname, model_data, global, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize simulation object &
          &with resonant subprocesses"
     write (u, "(A)")
 
     call global%set_log (var_str ("?resonance_history"), &
          .true., is_known = .true.)
     call global%set_real (var_str ("resonance_on_shell_limit"), &
          10._default, is_known = .true.)
 
     call simulation%init ([procname], &
          integrate=.false., generate=.false., local=global)
 
     call simulation%write_resonant_subprocess_data (u, 1)
 
     write (u, "(A)")
     write (u, "(A)")  "* Resonant subprocesses: generated library"
     write (u, "(A)")
 
     libname_generated = procname // "_R"
     lib => global%prclib_stack%get_library_ptr (libname_generated)
     if (associated (lib))  call lib%write (u, libpath=.false.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Generated process stack"
     write (u, "(A)")
 
     call global%process_stack%show (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Particle set"
     write (u, "(A)")
 
     pset = simulation%get_hard_particle_set (1)
     call pset%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize object for direct access"
     write (u, "(A)")
 
     call eio_in%init_direct &
          (n_beam = 0, n_in = 2, n_rem = 0, n_vir = 0, n_out = 3, &
          pdg = [-11, 11, 1, -2, 24], model=global%model)
     call eio_in%set_selection_indices (1, 1, 1, 1)
 
     sqrts = global%get_rval (var_str ("sqrts"))
     mw = 80._default   ! deliberately slightly different from true mw
     pp = sqrt (sqrts**2 - 4 * mw**2) / 2
 
     allocate (p (5), m (5))
     p(1) = vector4_moving (sqrts/2, sqrts/2, 3)
     m(1) = 0
     p(2) = vector4_moving (sqrts/2,-sqrts/2, 3)
     m(2) = 0
     p3(1) = pp/2
     p3(2) = mw/2
     p3(3) = 0
     p(3) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(3) = 0
     p3(2) = -mw/2
     p(4) = vector4_moving (sqrts/4, vector3_moving (p3))
     m(4) = 0
     p(5) = vector4_moving (sqrts/2,-pp, 1)
     m(5) = mw
     call eio_in%set_momentum (p, m**2)
 
     call eio_in%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Transfer and show particle set"
     write (u, "(A)")
 
     call simulation%read_event (eio_in)
     pset = simulation%get_hard_particle_set (1)
     call pset%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* (Re)calculate matrix element"
     write (u, "(A)")
 
     call simulation%recalculate (recover_phs = .false.)
     call simulation%evaluate_transforms ()
 
     write (u, "(A)")  "* Show event with sqme"
     write (u, "(A)")
 
     call eio_out%set_parameters (unit = u, &
          weights = .true., pacify = .true., compressed = .true.)
     call eio_out%init_out (var_str (""))
     call simulation%write_event (eio_out)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write event to separate file &
          &'simulations_14_event_verbose.log'"
 
     u_verbose = free_unit ()
     open (unit = u_verbose, file = "simulations_14_event_verbose.log", &
          status = "replace", action = "write")
     call simulation%write (u_verbose)
     write (u_verbose, *)
     call simulation%write_event (u_verbose, verbose =.true., testflag = .true.)
     close (u_verbose)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_14"
 
   end subroutine simulations_14
 
 @ %def simulations_14
 @
 \subsubsection{Resonant subprocess simulation}
 Prepare a process with resonances and enter resonant subprocesses in
 the simulation object.  Simulate events with selection of resonance
 histories.
 
 The process and its initialization is taken from [[processes_18]], but
 we need a complete \oMega\ matrix element here.
 <<Simulations: execute tests>>=
   call test (simulations_15, "simulations_15", &
        "resonant subprocesses in simulation", &
        u, results)
 <<Simulations: test declarations>>=
   public :: simulations_15
 <<Simulations: tests>>=
   subroutine simulations_15 (u)
     integer, intent(in) :: u
     type(string_t) :: libname, libname_generated
     type(string_t) :: procname
     type(string_t) :: model_name
     type(rt_data_t), target :: global
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     class(model_t), pointer :: model
     class(model_data_t), pointer :: model_data
     type(simulation_t), target :: simulation
     real(default) :: sqrts
     type(eio_dump_t) :: eio_out
     integer :: u_verbose
 
     write (u, "(A)")  "* Test output: simulations_15"
     write (u, "(A)")  "*   Purpose: generate event with resonant subprocess"
     write (u, "(A)")
 
     write (u, "(A)")  "* Build and load a test library with one process"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
 
     libname = "simulations_15_lib"
     procname = "simulations_15_p"
 
     call global%global_init ()
     call global%append_log (&
          var_str ("?rebuild_phase_space"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_grids"), .true., intrinsic = .true.)
     call global%append_log (&
          var_str ("?rebuild_events"), .true., intrinsic = .true.)
     call global%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     call global%set_int (var_str ("seed"), &
          0, is_known = .true.)
     call global%set_real (var_str ("sqrts"),&
          1000._default, is_known = .true.)
     call global%set_log (var_str ("?recover_beams"), &
          .false., is_known = .true.)
     call global%set_log (var_str ("?update_sqme"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?update_weight"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?update_event"), &
          .true., is_known = .true.)
     call global%set_log (var_str ("?resonance_history"), &
          .true., is_known = .true.)
     call global%set_real (var_str ("resonance_on_shell_limit"), &
          10._default, is_known = .true.)
 
     model_name = "SM"
     call global%select_model (model_name)
     allocate (model)
     call model%init_instance (global%model)
     model_data => model
 
     write (u, "(A)")  "* Initialize process library and process"
     write (u, "(A)")
 
     allocate (lib_entry)
     call lib_entry%init (libname)
     lib => lib_entry%process_library_t
     call global%add_prclib (lib_entry)
 
     call prepare_resonance_test_library &
          (lib, libname, procname, model_data, global, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize simulation object &
          &with resonant subprocesses"
     write (u, "(A)")
 
     call global%it_list%init ([1], [1000])
     call simulation%init ([procname], &
          integrate=.true., generate=.true., local=global)
 
     call simulation%write_resonant_subprocess_data (u, 1)
 
     write (u, "(A)")
     write (u, "(A)")  "* Generate event"
     write (u, "(A)")
 
     call simulation%init_process_selector ()
     call simulation%generate (1)
 
     call eio_out%set_parameters (unit = u, &
          weights = .true., pacify = .true., compressed = .true.)
     call eio_out%init_out (var_str (""))
     call simulation%write_event (eio_out)
 
     write (u, "(A)")
     write (u, "(A)")  "* Write event to separate file &
          &'simulations_15_event_verbose.log'"
 
     u_verbose = free_unit ()
     open (unit = u_verbose, file = "simulations_15_event_verbose.log", &
          status = "replace", action = "write")
     call simulation%write (u_verbose)
     write (u_verbose, *)
     call simulation%write_event (u_verbose, verbose =.true., testflag = .true.)
     close (u_verbose)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call simulation%final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: simulations_15"
 
   end subroutine simulations_15
 
 @ %def simulations_15
 @
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \chapter{More Unit Tests}
 
 This chapter collects some procedures for testing that can't be
 provided at the point where the corresponding modules are defined,
 because they use other modules of a different level.
 
 (We should move them back, collecting the high-level functionality in
 init/final hooks that we can set at runtime.)
 
 
 \section{Expression Testing}
 
 Expression objects are part of process and event objects, but the
 process and event object modules should not depend on the
 implementation of expressions.  Here, we collect unit tests that
 depend on expression implementation.
 <<[[expr_tests_ut.f90]]>>=
 <<File header>>
 module expr_tests_ut
 
   use unit_tests
   use expr_tests_uti
 
 <<Standard module head>>
 
 <<Expr tests: public test>>
 
 contains
 
 <<Expr tests: test driver>>
 
 end module expr_tests_ut
 @ %def expr_tests_ut
 @
 <<[[expr_tests_uti.f90]]>>=
 <<File header>>
 
 module expr_tests_uti
 
   <<Use kinds>>
   <<Use strings>>
     use format_defs, only: FMT_12
     use format_utils, only: write_separator
     use os_interface
     use sm_qcd
     use lorentz
     use ifiles
     use lexers
     use parser
     use model_data
     use interactions, only: reset_interaction_counter
     use process_libraries
     use subevents
     use subevt_expr
     use rng_base
     use mci_base
     use phs_base
     use variables, only: var_list_t
     use eval_trees
     use models
     use prc_core
     use prc_test
     use process, only: process_t
     use instances, only: process_instance_t
     use events
 
     use rng_base_ut, only: rng_test_factory_t
     use phs_base_ut, only: phs_test_config_t
 
 <<Standard module head>>
 
 <<Expr tests: test declarations>>
 
 contains
 
 <<Expr tests: tests>>
 
 <<Expr tests: test auxiliary>>
 
 end module expr_tests_uti
 
 @ %def expr_tests_uti
 @
 \subsection{Test}
 This is the master for calling self-test procedures.
 <<Expr tests: public test>>=
   public :: subevt_expr_test
 <<Expr tests: test driver>>=
   subroutine subevt_expr_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Expr tests: execute tests>>
 end subroutine subevt_expr_test
 
 @ %def subevt_expr_test
 @
 \subsubsection{Parton-event expressions}
 <<Expr tests: execute tests>>=
   call test (subevt_expr_1, "subevt_expr_1", &
        "parton-event expressions", &
        u, results)
 <<Expr tests: test declarations>>=
   public :: subevt_expr_1
 <<Expr tests: tests>>=
   subroutine subevt_expr_1 (u)
     integer, intent(in) :: u
     type(string_t) :: expr_text
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: pt_cuts, pt_scale, pt_fac_scale, pt_ren_scale
     type(parse_tree_t) :: pt_weight
     type(parse_node_t), pointer :: pn_cuts, pn_scale, pn_fac_scale, pn_ren_scale
     type(parse_node_t), pointer :: pn_weight
     type(eval_tree_factory_t) :: expr_factory
     type(os_data_t) :: os_data
     type(model_t), target :: model
     type(parton_expr_t), target :: expr
     real(default) :: E, Ex, m
     type(vector4_t), dimension(6) :: p
     integer :: i, pdg
     logical :: passed
     real(default) :: scale, fac_scale, ren_scale, weight
 
     write (u, "(A)")  "* Test output: subevt_expr_1"
     write (u, "(A)")  "*   Purpose: Set up a subevt and associated &
          &process-specific expressions"
     write (u, "(A)")
 
     call syntax_pexpr_init ()
 
     call syntax_model_file_init ()
     call os_data%init ()
     call model%read (var_str ("Test.mdl"), os_data)
 
     write (u, "(A)")  "* Expression texts"
     write (u, "(A)")
 
 
     expr_text = "all Pt > 100 [s]"
     write (u, "(A,A)")  "cuts = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_lexpr (pt_cuts, stream, .true.)
     call stream_final (stream)
     pn_cuts => pt_cuts%get_root_ptr ()
 
     expr_text = "sqrts"
     write (u, "(A,A)")  "scale = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_scale, stream, .true.)
     call stream_final (stream)
     pn_scale => pt_scale%get_root_ptr ()
 
     expr_text = "sqrts_hat"
     write (u, "(A,A)")  "fac_scale = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_fac_scale, stream, .true.)
     call stream_final (stream)
     pn_fac_scale => pt_fac_scale%get_root_ptr ()
 
     expr_text = "100"
     write (u, "(A,A)")  "ren_scale = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_ren_scale, stream, .true.)
     call stream_final (stream)
     pn_ren_scale => pt_ren_scale%get_root_ptr ()
 
     expr_text = "n_tot - n_in - n_out"
     write (u, "(A,A)")  "weight = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_weight, stream, .true.)
     call stream_final (stream)
     pn_weight => pt_weight%get_root_ptr ()
 
     call ifile_final (ifile)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize process expr"
     write (u, "(A)")
 
     call expr%setup_vars (1000._default)
     call expr%var_list%append_real (var_str ("tolerance"), 0._default)
     call expr%link_var_list (model%get_var_list_ptr ())
 
     call expr_factory%init (pn_cuts)
     call expr%setup_selection (expr_factory)
     call expr_factory%init (pn_scale)
     call expr%setup_scale (expr_factory)
     call expr_factory%init (pn_fac_scale)
     call expr%setup_fac_scale (expr_factory)
     call expr_factory%init (pn_ren_scale)
     call expr%setup_ren_scale (expr_factory)
     call expr_factory%init (pn_weight)
     call expr%setup_weight (expr_factory)
 
     call write_separator (u)
     call expr%write (u)
     call write_separator (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Fill subevt and evaluate expressions"
     write (u, "(A)")
 
     call subevt_init (expr%subevt_t, 6)
     E = 500._default
     Ex = 400._default
     m = 125._default
     pdg = 25
     p(1) = vector4_moving (E, sqrt (E**2 - m**2), 3)
     p(2) = vector4_moving (E, -sqrt (E**2 - m**2), 3)
     p(3) = vector4_moving (Ex, sqrt (Ex**2 - m**2), 3)
     p(4) = vector4_moving (Ex, -sqrt (Ex**2 - m**2), 3)
     p(5) = vector4_moving (Ex, sqrt (Ex**2 - m**2), 1)
     p(6) = vector4_moving (Ex, -sqrt (Ex**2 - m**2), 1)
 
     call expr%reset_contents ()
     do i = 1, 2
        call subevt_set_beam (expr%subevt_t, i, pdg, p(i), m**2)
     end do
     do i = 3, 4
        call subevt_set_incoming (expr%subevt_t, i, pdg, p(i), m**2)
     end do
     do i = 5, 6
        call subevt_set_outgoing (expr%subevt_t, i, pdg, p(i), m**2)
     end do
     expr%sqrts_hat = subevt_get_sqrts_hat (expr%subevt_t)
     expr%n_in = 2
     expr%n_out = 2
     expr%n_tot = 4
     expr%subevt_filled = .true.
 
     call expr%evaluate (passed, scale, fac_scale, ren_scale, weight)
 
     write (u, "(A,L1)")      "Event has passed      = ", passed
     write (u, "(A," // FMT_12 // ")")  "Scale                 = ", scale
     write (u, "(A," // FMT_12 // ")")  "Factorization scale   = ", fac_scale
     write (u, "(A," // FMT_12 // ")")  "Renormalization scale = ", ren_scale
     write (u, "(A," // FMT_12 // ")")  "Weight                = ", weight
     write (u, "(A)")
 
     call write_separator (u)
     call expr%write (u)
     call write_separator (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call expr%final ()
 
     call model%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: subevt_expr_1"
 
   end subroutine subevt_expr_1
 
 @ %def subevt_expr_1
 @
 \subsubsection{Parton-event expressions}
 <<Expr tests: execute tests>>=
   call test (subevt_expr_2, "subevt_expr_2", &
        "parton-event expressions", &
        u, results)
 <<Expr tests: test declarations>>=
   public :: subevt_expr_2
 <<Expr tests: tests>>=
   subroutine subevt_expr_2 (u)
     integer, intent(in) :: u
     type(string_t) :: expr_text
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: pt_selection
     type(parse_tree_t) :: pt_reweight, pt_analysis
     type(parse_node_t), pointer :: pn_selection
     type(parse_node_t), pointer :: pn_reweight, pn_analysis
     type(os_data_t) :: os_data
     type(model_t), target :: model
     type(eval_tree_factory_t) :: expr_factory
     type(event_expr_t), target :: expr
     real(default) :: E, Ex, m
     type(vector4_t), dimension(6) :: p
     integer :: i, pdg
     logical :: passed
     real(default) :: reweight
     logical :: analysis_flag
 
     write (u, "(A)")  "* Test output: subevt_expr_2"
     write (u, "(A)")  "*   Purpose: Set up a subevt and associated &
          &process-specific expressions"
     write (u, "(A)")
 
     call syntax_pexpr_init ()
 
     call syntax_model_file_init ()
     call os_data%init ()
     call model%read (var_str ("Test.mdl"), os_data)
 
     write (u, "(A)")  "* Expression texts"
     write (u, "(A)")
 
 
     expr_text = "all Pt > 100 [s]"
     write (u, "(A,A)")  "selection = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_lexpr (pt_selection, stream, .true.)
     call stream_final (stream)
     pn_selection => pt_selection%get_root_ptr ()
 
     expr_text = "n_tot - n_in - n_out"
     write (u, "(A,A)")  "reweight = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_reweight, stream, .true.)
     call stream_final (stream)
     pn_reweight => pt_reweight%get_root_ptr ()
 
     expr_text = "true"
     write (u, "(A,A)")  "analysis = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_lexpr (pt_analysis, stream, .true.)
     call stream_final (stream)
     pn_analysis => pt_analysis%get_root_ptr ()
 
     call ifile_final (ifile)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize process expr"
     write (u, "(A)")
 
     call expr%setup_vars (1000._default)
     call expr%link_var_list (model%get_var_list_ptr ())
     call expr%var_list%append_real (var_str ("tolerance"), 0._default)
 
     call expr_factory%init (pn_selection)
     call expr%setup_selection (expr_factory)
     call expr_factory%init (pn_analysis)
     call expr%setup_analysis (expr_factory)
     call expr_factory%init (pn_reweight)
     call expr%setup_reweight (expr_factory)
 
     call write_separator (u)
     call expr%write (u)
     call write_separator (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Fill subevt and evaluate expressions"
     write (u, "(A)")
 
     call subevt_init (expr%subevt_t, 6)
     E = 500._default
     Ex = 400._default
     m = 125._default
     pdg = 25
     p(1) = vector4_moving (E, sqrt (E**2 - m**2), 3)
     p(2) = vector4_moving (E, -sqrt (E**2 - m**2), 3)
     p(3) = vector4_moving (Ex, sqrt (Ex**2 - m**2), 3)
     p(4) = vector4_moving (Ex, -sqrt (Ex**2 - m**2), 3)
     p(5) = vector4_moving (Ex, sqrt (Ex**2 - m**2), 1)
     p(6) = vector4_moving (Ex, -sqrt (Ex**2 - m**2), 1)
 
     call expr%reset_contents ()
     do i = 1, 2
        call subevt_set_beam (expr%subevt_t, i, pdg, p(i), m**2)
     end do
     do i = 3, 4
        call subevt_set_incoming (expr%subevt_t, i, pdg, p(i), m**2)
     end do
     do i = 5, 6
        call subevt_set_outgoing (expr%subevt_t, i, pdg, p(i), m**2)
     end do
     expr%sqrts_hat = subevt_get_sqrts_hat (expr%subevt_t)
     expr%n_in = 2
     expr%n_out = 2
     expr%n_tot = 4
     expr%subevt_filled = .true.
 
     call expr%evaluate (passed, reweight, analysis_flag)
 
     write (u, "(A,L1)")      "Event has passed      = ", passed
     write (u, "(A," // FMT_12 // ")")  "Reweighting factor    = ", reweight
     write (u, "(A,L1)")      "Analysis flag         = ", analysis_flag
     write (u, "(A)")
 
     call write_separator (u)
     call expr%write (u)
     call write_separator (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call expr%final ()
 
     call model%final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: subevt_expr_2"
 
   end subroutine subevt_expr_2
 
 @ %def subevt_expr_2
 @
 \subsubsection{Processes: handle partonic cuts}
 Initialize a process and process instance, choose a sampling point and
 fill the process instance, evaluating a given cut configuration.
 
 We use the same trivial process as for the previous test.  All
 momentum and state dependence is trivial, so we just test basic
 functionality.
 <<Expr tests: execute tests>>=
   call test (processes_5, "processes_5", &
        "handle cuts (partonic event)", &
        u, results)
 <<Expr tests: test declarations>>=
   public :: processes_5
 <<Expr tests: tests>>=
   subroutine processes_5 (u)
     integer, intent(in) :: u
     type(string_t) :: cut_expr_text
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: parse_tree
     type(eval_tree_factory_t) :: expr_factory
     type(process_library_t), target :: lib
     type(string_t) :: libname
     type(string_t) :: procname
     type(os_data_t) :: os_data
     type(model_t), pointer :: model_tmp
     type(model_t), pointer :: model
     type(var_list_t), target :: var_list
     type(process_t), allocatable, target :: process
     class(phs_config_t), allocatable :: phs_config_template
     real(default) :: sqrts
     type(process_instance_t), allocatable, target :: process_instance
 
     write (u, "(A)")  "* Test output: processes_5"
     write (u, "(A)")  "*   Purpose: create a process &
          &and fill a process instance"
     write (u, "(A)")
 
     write (u, "(A)")  "* Prepare a cut expression"
     write (u, "(A)")
 
     call syntax_pexpr_init ()
     cut_expr_text = "all Pt > 100 [s]"
     call ifile_append (ifile, cut_expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_lexpr (parse_tree, stream, .true.)
 
     write (u, "(A)")  "* Build and initialize a test process"
     write (u, "(A)")
 
     libname = "processes5"
     procname = libname
 
     call os_data%init ()
     call prc_test_create_library (libname, lib)
 
     call syntax_model_file_init ()
     allocate (model_tmp)
     call model_tmp%read (var_str ("Test.mdl"), os_data)
     call var_list%init_snapshot (model_tmp%get_var_list_ptr ())
     model => model_tmp
 
     call reset_interaction_counter ()
 
     call var_list%append_real (var_str ("tolerance"), 0._default)
     call var_list%append_log (var_str ("?alphas_is_fixed"), .true.)
     call var_list%append_int (var_str ("seed"), 0)
 
     allocate (process)
     call process%init (procname, lib, os_data, model, var_list)
 
     call var_list%final ()
 
     allocate (phs_test_config_t :: phs_config_template)
     call process%setup_test_cores ()
     call process%init_components (phs_config_template)
 
     write (u, "(A)")  "* Prepare a trivial beam setup"
     write (u, "(A)")
 
     sqrts = 1000
     call process%setup_beams_sqrts (sqrts, i_core = 1)
     call process%configure_phs ()
     call process%setup_mci (dispatch_mci_empty)
 
     write (u, "(A)")  "* Complete process initialization and set cuts"
     write (u, "(A)")
 
     call process%setup_terms ()
     call expr_factory%init (parse_tree%get_root_ptr ())
     call process%set_cuts (expr_factory)
     call process%write (.false., u, &
          show_var_list=.true., show_expressions=.true., show_os_data=.false.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Create a process instance"
     write (u, "(A)")
 
     allocate (process_instance)
     call process_instance%init (process)
 
     write (u, "(A)")
     write (u, "(A)")  "* Inject a set of random numbers"
     write (u, "(A)")
 
     call process_instance%choose_mci (1)
     call process_instance%set_mcpar ([0._default, 0._default])
 
     write (u, "(A)")
     write (u, "(A)")  "* Set up kinematics and subevt, check cuts (should fail)"
     write (u, "(A)")
 
     call process_instance%select_channel (1)
     call process_instance%compute_seed_kinematics ()
     call process_instance%compute_hard_kinematics ()
     call process_instance%compute_eff_kinematics ()
     call process_instance%evaluate_expressions ()
     call process_instance%compute_other_channels ()
 
     call process_instance%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Evaluate for another set (should succeed)"
     write (u, "(A)")
 
     call process_instance%reset ()
     call process_instance%set_mcpar ([0.5_default, 0.125_default])
     call process_instance%select_channel (1)
     call process_instance%compute_seed_kinematics ()
     call process_instance%compute_hard_kinematics ()
     call process_instance%compute_eff_kinematics ()
     call process_instance%evaluate_expressions ()
     call process_instance%compute_other_channels ()
     call process_instance%evaluate_trace ()
 
     call process_instance%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Evaluate for another set using convenience procedure &
          &(failure)"
     write (u, "(A)")
 
     call process_instance%evaluate_sqme (1, [0.0_default, 0.2_default])
 
     call process_instance%write_header (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Evaluate for another set using convenience procedure &
          &(success)"
     write (u, "(A)")
 
     call process_instance%evaluate_sqme (1, [0.1_default, 0.2_default])
 
     call process_instance%write_header (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call process_instance%final ()
     deallocate (process_instance)
 
     call process%final ()
     deallocate (process)
 
     call parse_tree_final (parse_tree)
     call stream_final (stream)
     call ifile_final (ifile)
     call syntax_pexpr_final ()
 
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: processes_5"
 
   end subroutine processes_5
 
 @ %def processes_5
 @ Trivial for testing: do not allocate the MCI record.
 <<Expr tests: test auxiliary>>=
   subroutine dispatch_mci_empty (mci, var_list, process_id, is_nlo)
     class(mci_t), allocatable, intent(out) :: mci
     type(var_list_t), intent(in) :: var_list
     type(string_t), intent(in) :: process_id
     logical, intent(in), optional :: is_nlo
   end subroutine dispatch_mci_empty
  
 @ %def dispatch_mci_empty
 @
 \subsubsection{Processes: scales and such}
 Initialize a process and process instance, choose a sampling point and
 fill the process instance, evaluating a given cut configuration.
 
 We use the same trivial process as for the previous test.  All
 momentum and state dependence is trivial, so we just test basic
 functionality.
 <<Expr tests: execute tests>>=
   call test (processes_6, "processes_6", &
        "handle scales and weight (partonic event)", &
        u, results)
 <<Expr tests: test declarations>>=
   public :: processes_6
 <<Expr tests: tests>>=
   subroutine processes_6 (u)
     integer, intent(in) :: u
     type(string_t) :: expr_text
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: pt_scale, pt_fac_scale, pt_ren_scale, pt_weight
     type(process_library_t), target :: lib
     type(string_t) :: libname
     type(string_t) :: procname
     type(os_data_t) :: os_data
     type(model_t), pointer :: model_tmp
     type(model_t), pointer :: model
     type(var_list_t), target :: var_list
     type(process_t), allocatable, target :: process
     class(phs_config_t), allocatable :: phs_config_template
     real(default) :: sqrts
     type(process_instance_t), allocatable, target :: process_instance
     type(eval_tree_factory_t) :: expr_factory
 
     write (u, "(A)")  "* Test output: processes_6"
     write (u, "(A)")  "*   Purpose: create a process &
          &and fill a process instance"
     write (u, "(A)")
 
     write (u, "(A)")  "* Prepare expressions"
     write (u, "(A)")
 
     call syntax_pexpr_init ()
 
     expr_text = "sqrts - 100 GeV"
     write (u, "(A,A)")  "scale = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_scale, stream, .true.)
     call stream_final (stream)
 
     expr_text = "sqrts_hat"
     write (u, "(A,A)")  "fac_scale = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_fac_scale, stream, .true.)
     call stream_final (stream)
 
     expr_text = "eval sqrt (M2) [collect [s]]"
     write (u, "(A,A)")  "ren_scale = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_ren_scale, stream, .true.)
     call stream_final (stream)
 
     expr_text = "n_tot * n_in * n_out * (eval Phi / pi [s])"
     write (u, "(A,A)")  "weight = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_weight, stream, .true.)
     call stream_final (stream)
 
     call ifile_final (ifile)
 
     write (u, "(A)")
     write (u, "(A)")  "* Build and initialize a test process"
     write (u, "(A)")
 
     libname = "processes4"
     procname = libname
 
     call os_data%init ()
     call prc_test_create_library (libname, lib)
 
     call syntax_model_file_init ()
     allocate (model_tmp)
     call model_tmp%read (var_str ("Test.mdl"), os_data)
     call var_list%init_snapshot (model_tmp%get_var_list_ptr ())
     model => model_tmp
 
     call var_list%append_log (var_str ("?alphas_is_fixed"), .true.)
     call var_list%append_int (var_str ("seed"), 0)
 
     call reset_interaction_counter ()
 
     allocate (process)
     call process%init (procname, lib, os_data, model, var_list)
 
     call var_list%final ()
 
     call process%setup_test_cores ()
     allocate (phs_test_config_t :: phs_config_template)
     call process%init_components (phs_config_template)
 
     write (u, "(A)")  "* Prepare a trivial beam setup"
     write (u, "(A)")
 
     sqrts = 1000
     call process%setup_beams_sqrts (sqrts, i_core = 1)
     call process%configure_phs ()
     call process%setup_mci (dispatch_mci_empty)
 
     write (u, "(A)")  "* Complete process initialization and set cuts"
     write (u, "(A)")
 
     call process%setup_terms ()
     call expr_factory%init (pt_scale%get_root_ptr ())
     call process%set_scale (expr_factory)
     call expr_factory%init (pt_fac_scale%get_root_ptr ())
     call process%set_fac_scale (expr_factory)
     call expr_factory%init (pt_ren_scale%get_root_ptr ())
     call process%set_ren_scale (expr_factory)
     call expr_factory%init (pt_weight%get_root_ptr ())
     call process%set_weight (expr_factory)
     call process%write (.false., u, show_expressions=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Create a process instance and evaluate"
     write (u, "(A)")
 
     allocate (process_instance)
     call process_instance%init (process)
     call process_instance%choose_mci (1)
     call process_instance%evaluate_sqme (1, [0.5_default, 0.125_default])
 
     call process_instance%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call process_instance%final ()
     deallocate (process_instance)
 
     call process%final ()
     deallocate (process)
 
     call parse_tree_final (pt_scale)
     call parse_tree_final (pt_fac_scale)
     call parse_tree_final (pt_ren_scale)
     call parse_tree_final (pt_weight)
     call syntax_pexpr_final ()
 
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: processes_6"
 
   end subroutine processes_6
 
 @ %def processes_6
 @
 \subsubsection{Event expressions}
 After generating an event, fill the [[subevt]] and evaluate expressions for
 selection, reweighting, and analysis.
 <<Expr tests: execute tests>>=
   call test (events_3, "events_3", &
        "expression evaluation", &
        u, results)
 <<Expr tests: test declarations>>=
   public :: events_3
 <<Expr tests: tests>>=
   subroutine events_3 (u)
     use processes_ut, only: prepare_test_process, cleanup_test_process
     integer, intent(in) :: u
     type(string_t) :: expr_text
     type(ifile_t) :: ifile
     type(stream_t) :: stream
     type(parse_tree_t) :: pt_selection, pt_reweight, pt_analysis
     type(eval_tree_factory_t) :: expr_factory
     type(event_t), allocatable, target :: event
     type(process_t), allocatable, target :: process
     type(process_instance_t), allocatable, target :: process_instance
     type(os_data_t) :: os_data
     type(model_t), pointer :: model
     type(var_list_t), target :: var_list
 
     write (u, "(A)")  "* Test output: events_3"
     write (u, "(A)")  "*   Purpose: generate an event and evaluate expressions"
     write (u, "(A)")
 
     call syntax_pexpr_init ()
 
     write (u, "(A)")  "* Expression texts"
     write (u, "(A)")
 
     expr_text = "all Pt > 100 [s]"
     write (u, "(A,A)")  "selection = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_lexpr (pt_selection, stream, .true.)
     call stream_final (stream)
 
     expr_text = "1 + sqrts_hat / sqrts"
     write (u, "(A,A)")  "reweight = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_expr (pt_reweight, stream, .true.)
     call stream_final (stream)
 
     expr_text = "true"
     write (u, "(A,A)")  "analysis = ", char (expr_text)
     call ifile_clear (ifile)
     call ifile_append (ifile, expr_text)
     call stream_init (stream, ifile)
     call parse_tree_init_lexpr (pt_analysis, stream, .true.)
     call stream_final (stream)
 
     call ifile_final (ifile)
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize test process event"
 
     call os_data%init ()
 
     call syntax_model_file_init ()
     allocate (model)
     call model%read (var_str ("Test.mdl"), os_data)
     call var_list%init_snapshot (model%get_var_list_ptr ())
 
     call var_list%append_log (var_str ("?alphas_is_fixed"), .true.)
     call var_list%append_int (var_str ("seed"), 0)
 
     allocate (process)
     allocate (process_instance)
     call prepare_test_process (process, process_instance, model, var_list)
 
     call var_list%final ()
 
     call process_instance%setup_event_data ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Initialize event object and set expressions"
 
     allocate (event)
     call event%basic_init ()
 
     call expr_factory%init (pt_selection%get_root_ptr ())
     call event%set_selection (expr_factory)
     call expr_factory%init (pt_reweight%get_root_ptr ())
     call event%set_reweight (expr_factory)
     call expr_factory%init (pt_analysis%get_root_ptr ())
     call event%set_analysis (expr_factory)
 
     call event%connect (process_instance, process%get_model_ptr ())
     call event%expr%var_list%append_real (var_str ("tolerance"), 0._default)
     call event%setup_expressions ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Generate test process event"
 
     call process_instance%generate_weighted_event (1)
 
     write (u, "(A)")
     write (u, "(A)")  "* Fill event object and evaluate expressions"
     write (u, "(A)")
 
     call event%generate (1, [0.4_default, 0.4_default])
     call event%set_index (42)
     call event%evaluate_expressions ()
     call event%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call event%final ()
     deallocate (event)
 
     call cleanup_test_process (process, process_instance)
     deallocate (process_instance)
     deallocate (process)
 
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: events_3"
 
   end subroutine events_3
 
 @ %def events_3
 @
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \chapter{Top Level}
 
 The top level consists of
 \begin{description}
 \item[commands]
   Defines generic command-list and command objects, and all specific
   implementations.  Each command type provides a specific
   functionality.  Together with the modules that provide expressions
   and variables, this module defines the Sindarin language.
 \item[whizard]
   This module interprets streams of various kind in terms of the
   command language.  It also contains the unit-test feature.  We also
   define the externally visible procedures here, for the \whizard\ as
   a library.
 \item[main]
   The driver for \whizard\ as a stand-alone program.  Contains the
   command-line interpreter.
 \item[whizard\_c\_interface]
   Alternative top-level procedures, for use in the context of a
   C-compatible caller program.
 \end{description}
 
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Commands}
 This module defines the command language of the main input file.
 <<[[commands.f90]]>>=
 <<File header>>
 
 module commands
 
 <<Use kinds>>
 <<Use strings>>
 <<Use debug>>
   use io_units
   use string_utils, only: lower_case, split_string, str
   use format_utils, only: write_indent
   use format_defs, only: FMT_14, FMT_19
   use diagnostics
 
   use physics_defs
   use sorting
   use sf_lhapdf, only: lhapdf_global_reset
   use os_interface
   use ifiles
   use lexers
   use syntax_rules
   use parser
   use analysis
   use pdg_arrays
   use variables, only: var_list_t, V_NONE, V_LOG, V_INT, V_REAL, V_CMPLX, V_STR, V_PDG
   use observables, only: var_list_check_observable
   use observables, only: var_list_check_result_var
   use eval_trees
   use models
   use auto_components
   use flavors
   use polarizations
   use particle_specifiers
   use process_libraries
   use process
   use instances
   use prclib_stacks
   use slha_interface
   use user_files
   use eio_data
   use rt_data
 
   use process_configurations
   use compilations, only: compile_library, compile_executable
   use integrations, only: integrate_process
   use restricted_subprocesses, only: get_libname_res
   use restricted_subprocesses, only: spawn_resonant_subprocess_libraries
   use event_streams
   use simulations
 
   use radiation_generator
 
 <<Use mpi f08>>
 
 <<Standard module head>>
 
 <<Commands: public>>
 
 <<Commands: types>>
 
 <<Commands: variables>>
 
 <<Commands: parameters>>
 
 <<Commands: interfaces>>
 
 contains
 
 <<Commands: procedures>>
 
 end module commands
 @ %def commands
 @
 \subsection{The command type}
 The command type is a generic type that holds any command, compiled
 for execution.
 
 Each command may come with its own local environment.  The command list that
 determines this environment is allocated as [[options]], if necessary.  (It
 has to be allocated as a pointer because the type definition is recursive.) The
 local environment is available as a pointer which either points to the global
 environment, or is explicitly allocated and initialized.
 <<Commands: types>>=
   type, abstract :: command_t
      type(parse_node_t), pointer :: pn => null ()
      class(command_t), pointer :: next => null ()
      type(parse_node_t), pointer :: pn_opt => null ()
      type(command_list_t), pointer :: options => null ()
      type(rt_data_t), pointer :: local => null ()
    contains
    <<Commands: command: TBP>>
   end type command_t
 
 @ %def command_t
 @ Finalizer: If there is an option list, finalize the option list and
 deallocate.  If not, the local environment is just a pointer.
 <<Commands: command: TBP>>=
   procedure :: final => command_final
 <<Commands: procedures>>=
   recursive subroutine command_final (cmd)
     class(command_t), intent(inout) :: cmd
     if (associated (cmd%options)) then
        call cmd%options%final ()
        deallocate (cmd%options)
        call cmd%local%local_final ()
        deallocate (cmd%local)
     else
        cmd%local => null ()
     end if
   end subroutine command_final
 
 @ %def command_final
 @ Allocate a command with the appropriate concrete type.  Store the
 parse node pointer in the command object, so we can reference to it
 when compiling.
 <<Commands: procedures>>=
   subroutine dispatch_command (command, pn)
     class(command_t), intent(inout), pointer :: command
     type(parse_node_t), intent(in), target :: pn
     select case (char (parse_node_get_rule_key (pn)))
     case ("cmd_model")
        allocate (cmd_model_t :: command)
     case ("cmd_library")
        allocate (cmd_library_t :: command)
     case ("cmd_process")
        allocate (cmd_process_t :: command)
     case ("cmd_nlo")
        allocate (cmd_nlo_t :: command)
     case ("cmd_compile")
        allocate (cmd_compile_t :: command)
     case ("cmd_exec")
        allocate (cmd_exec_t :: command)
      case ("cmd_num", "cmd_complex", "cmd_real", "cmd_int", &
            "cmd_log_decl", "cmd_log", "cmd_string", "cmd_string_decl", &
            "cmd_alias", "cmd_result")
        allocate (cmd_var_t :: command)
     case ("cmd_slha")
        allocate (cmd_slha_t :: command)
     case ("cmd_show")
        allocate (cmd_show_t :: command)
     case ("cmd_clear")
        allocate (cmd_clear_t :: command)
     case ("cmd_expect")
        allocate (cmd_expect_t :: command)
     case ("cmd_beams")
        allocate (cmd_beams_t :: command)
     case ("cmd_beams_pol_density")
        allocate (cmd_beams_pol_density_t :: command)
     case ("cmd_beams_pol_fraction")
        allocate (cmd_beams_pol_fraction_t :: command)
     case ("cmd_beams_momentum")
        allocate (cmd_beams_momentum_t :: command)
     case ("cmd_beams_theta")
        allocate (cmd_beams_theta_t :: command)
     case ("cmd_beams_phi")
        allocate (cmd_beams_phi_t :: command)
     case ("cmd_cuts")
        allocate (cmd_cuts_t :: command)
     case ("cmd_scale")
        allocate (cmd_scale_t :: command)
     case ("cmd_fac_scale")
        allocate (cmd_fac_scale_t :: command)
     case ("cmd_ren_scale")
        allocate (cmd_ren_scale_t :: command)
     case ("cmd_weight")
        allocate (cmd_weight_t :: command)
     case ("cmd_selection")
        allocate (cmd_selection_t :: command)
     case ("cmd_reweight")
        allocate (cmd_reweight_t :: command)
     case ("cmd_iterations")
        allocate (cmd_iterations_t :: command)
     case ("cmd_integrate")
        allocate (cmd_integrate_t :: command)
     case ("cmd_observable")
        allocate (cmd_observable_t :: command)
     case ("cmd_histogram")
        allocate (cmd_histogram_t :: command)
     case ("cmd_plot")
        allocate (cmd_plot_t :: command)
     case ("cmd_graph")
        allocate (cmd_graph_t :: command)
     case ("cmd_record")
        allocate (cmd_record_t :: command)
     case ("cmd_analysis")
        allocate (cmd_analysis_t :: command)
     case ("cmd_alt_setup")
        allocate (cmd_alt_setup_t :: command)
     case ("cmd_unstable")
        allocate (cmd_unstable_t :: command)
     case ("cmd_stable")
        allocate (cmd_stable_t :: command)
     case ("cmd_polarized")
        allocate (cmd_polarized_t :: command)
     case ("cmd_unpolarized")
        allocate (cmd_unpolarized_t :: command)
     case ("cmd_sample_format")
        allocate (cmd_sample_format_t :: command)
     case ("cmd_simulate")
        allocate (cmd_simulate_t :: command)
     case ("cmd_rescan")
        allocate (cmd_rescan_t :: command)
     case ("cmd_write_analysis")
        allocate (cmd_write_analysis_t :: command)
     case ("cmd_compile_analysis")
        allocate (cmd_compile_analysis_t :: command)
     case ("cmd_open_out")
        allocate (cmd_open_out_t :: command)
     case ("cmd_close_out")
        allocate (cmd_close_out_t :: command)
     case ("cmd_printf")
        allocate (cmd_printf_t :: command)
     case ("cmd_scan")
        allocate (cmd_scan_t :: command)
     case ("cmd_if")
        allocate (cmd_if_t :: command)
     case ("cmd_include")
        allocate (cmd_include_t :: command)
     case ("cmd_export")
        allocate (cmd_export_t :: command)
     case ("cmd_quit")
        allocate (cmd_quit_t :: command)
     case default
        print *, char (parse_node_get_rule_key (pn))
        call msg_bug ("Command not implemented")
     end select
     command%pn => pn
   end subroutine dispatch_command
 
 @ %def dispatch_command
 @ Output.  We allow for indentation so we can display a command tree.
 <<Commands: command: TBP>>=
   procedure (command_write), deferred :: write
 <<Commands: interfaces>>=
   abstract interface
      subroutine command_write (cmd, unit, indent)
        import
        class(command_t), intent(in) :: cmd
        integer, intent(in), optional :: unit, indent
      end subroutine command_write
   end interface
 
 @ %def command_write
 @ Compile a command.  The command type is already fixed, so this is a
 deferred type-bound procedure.
 <<Commands: command: TBP>>=
   procedure (command_compile), deferred :: compile
 <<Commands: interfaces>>=
   abstract interface
      subroutine command_compile (cmd, global)
        import
        class(command_t), intent(inout) :: cmd
        type(rt_data_t), intent(inout), target :: global
      end subroutine command_compile
   end interface
 
 @ %def command_compile
 @ Execute a command.  This will use and/or modify the runtime data
 set.  If the [[quit]] flag is set, the caller should terminate command
 execution.
 <<Commands: command: TBP>>=
   procedure (command_execute), deferred :: execute
 <<Commands: interfaces>>=
   abstract interface
      subroutine command_execute (cmd, global)
        import
        class(command_t), intent(inout) :: cmd
        type(rt_data_t), intent(inout), target :: global
      end subroutine command_execute
   end interface
 
 @ %def command_execute
 @
 \subsection{Options}
 The [[options]] command list is allocated, initialized, and executed, if the
 command is associated with an option text in curly braces.  If present, a
 separate local runtime data set [[local]] will be allocated and initialized;
 otherwise, [[local]] becomes a pointer to the global dataset.
 
 For output, we indent the options list.
 <<Commands: command: TBP>>=
   procedure :: write_options => command_write_options
 <<Commands: procedures>>=
   recursive subroutine command_write_options (cmd, unit, indent)
     class(command_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: ind
     ind = 1;  if (present (indent))  ind = indent + 1
     if (associated (cmd%options))  call cmd%options%write (unit, ind)
   end subroutine command_write_options
 
 @ %def command_write_options
 @ Compile the options list, if any.  This implies initialization of the local
 environment.  Should be done once the [[pn_opt]] node has been assigned (if
 applicable), but before the actual command compilation.
 <<Commands: command: TBP>>=
   procedure :: compile_options => command_compile_options
 <<Commands: procedures>>=
   recursive subroutine command_compile_options (cmd, global)
     class(command_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     if (associated (cmd%pn_opt)) then
        allocate (cmd%local)
        call cmd%local%local_init (global)
        call global%copy_globals (cmd%local)
        allocate (cmd%options)
        call cmd%options%compile (cmd%pn_opt, cmd%local)
        call global%restore_globals (cmd%local)
        call cmd%local%deactivate ()
     else
        cmd%local => global
     end if
   end subroutine command_compile_options
 
 @ %def command_compile_options
 @ Execute options.  First prepare the local environment, then execute the
 command list.
 <<Commands: command: TBP>>=
   procedure :: execute_options => cmd_execute_options
 <<Commands: procedures>>=
   recursive subroutine cmd_execute_options (cmd, global)
     class(command_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     if (associated (cmd%options)) then
        call cmd%local%activate ()
        call cmd%options%execute (cmd%local)
     end if
   end subroutine cmd_execute_options
 
 @ %def cmd_execute_options
 @ This must be called after the parent command has been executed, to undo
 temporary modifications to the environment.  Note that some modifications to
 [[global]] can become permanent.
 <<Commands: command: TBP>>=
   procedure :: reset_options => cmd_reset_options
 <<Commands: procedures>>=
   subroutine cmd_reset_options (cmd, global)
     class(command_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     if (associated (cmd%options)) then
        call cmd%local%deactivate (global)
     end if
   end subroutine cmd_reset_options
 
 @ %def cmd_reset_options
 @
 \subsection{Specific command types}
 \subsubsection{Model configuration}
 The command declares a model, looks for the specified file and loads
 it.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_model_t
      private
      type(string_t) :: name
      type(string_t) :: scheme
      logical :: ufo_model = .false.
      logical :: ufo_path_set = .false.
      type(string_t) :: ufo_path
    contains
    <<Commands: cmd model: TBP>>
   end type cmd_model_t
 
 @ %def cmd_model_t
 @ Output
 <<Commands: cmd model: TBP>>=
   procedure :: write => cmd_model_write
 <<Commands: procedures>>=
   subroutine cmd_model_write (cmd, unit, indent)
     class(cmd_model_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,1x,'""',A,'""')", advance="no")  "model =", char (cmd%name)
     if (cmd%ufo_model) then
        if (cmd%ufo_path_set) then
           write (u, "(1x,A,A,A)")  "(ufo (", char (cmd%ufo_path), "))"
        else
           write (u, "(1x,A)")  "(ufo)"
        end if
     else if (cmd%scheme /= "") then
        write (u, "(1x,'(',A,')')")  char (cmd%scheme)
     else
        write (u, *)
     end if
   end subroutine cmd_model_write
 
 @ %def cmd_model_write
 @ Compile.  Get the model name and read the model from file, so it is
 readily available when the command list is executed.  If the model has a
 scheme argument, take this into account.
 
 Assign the model pointer in the [[global]] record, so it can be used for
 (read-only) variable lookup while compiling further commands.
 <<Commands: cmd model: TBP>>=
   procedure :: compile => cmd_model_compile
 <<Commands: procedures>>=
   subroutine cmd_model_compile (cmd, global)
     class(cmd_model_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_name, pn_arg, pn_scheme
     type(parse_node_t), pointer :: pn_ufo_arg, pn_path
     type(model_t), pointer :: model
     type(string_t) :: scheme
     pn_name => cmd%pn%get_sub_ptr (3)
     pn_arg => pn_name%get_next_ptr ()
     if (associated (pn_arg)) then
        pn_scheme => pn_arg%get_sub_ptr ()
     else
        pn_scheme => null ()
     end if
     cmd%name = pn_name%get_string ()
     if (associated (pn_scheme)) then
        select case (char (pn_scheme%get_rule_key ()))
        case ("ufo_spec")
           cmd%ufo_model = .true.
           pn_ufo_arg => pn_scheme%get_sub_ptr (2)
           if (associated (pn_ufo_arg)) then
              pn_path => pn_ufo_arg%get_sub_ptr ()
              cmd%ufo_path_set = .true.
              cmd%ufo_path = pn_path%get_string ()
           end if
        case default
           scheme = pn_scheme%get_string ()
     select case (char (lower_case (scheme)))
     case ("ufo");  cmd%ufo_model = .true.
           case default;  cmd%scheme = scheme
           end select
        end select
        if (cmd%ufo_model) then
           if (cmd%ufo_path_set) then
              call preload_ufo_model (model, cmd%name, cmd%ufo_path)
           else
              call preload_ufo_model (model, cmd%name)
           end if
        else
           call preload_model (model, cmd%name, cmd%scheme)
        end if
     else
        cmd%scheme = ""
        call preload_model (model, cmd%name)
     end if
     global%model => model
     if (associated (global%model)) then
        call global%model%link_var_list (global%var_list)
     end if
   contains
     subroutine preload_model (model, name, scheme)
       type(model_t), pointer, intent(out) :: model
       type(string_t), intent(in) :: name
       type(string_t), intent(in), optional :: scheme
       model => null ()
       if (associated (global%model)) then
          if (global%model%matches (name, scheme)) then
             model => global%model
          end if
       end if
       if (.not. associated (model)) then
          if (global%model_list%model_exists (name, scheme)) then
             model => global%model_list%get_model_ptr (name, scheme)
          else
             call global%read_model (name, model, scheme)
          end if
       end if
     end subroutine preload_model
     subroutine preload_ufo_model (model, name, ufo_path)
       type(model_t), pointer, intent(out) :: model
       type(string_t), intent(in) :: name
       type(string_t), intent(in), optional :: ufo_path
       model => null ()
       if (associated (global%model)) then
          if (global%model%matches (name, ufo=.true., ufo_path=ufo_path)) then
             model => global%model
          end if
       end if
       if (.not. associated (model)) then
          if (global%model_list%model_exists (name, &
               ufo=.true., ufo_path=ufo_path)) then
             model => global%model_list%get_model_ptr (name, &
                  ufo=.true., ufo_path=ufo_path)
          else
             call global%read_ufo_model (name, model, ufo_path=ufo_path)
          end if
       end if
     end subroutine preload_ufo_model
   end subroutine cmd_model_compile
 
 @ %def cmd_model_compile
 @ Execute: Insert a pointer into the global data record and reassign
 the variable list.
 <<Commands: cmd model: TBP>>=
   procedure :: execute => cmd_model_execute
 <<Commands: procedures>>=
   subroutine cmd_model_execute (cmd, global)
     class(cmd_model_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     if (cmd%ufo_model) then
        if (cmd%ufo_path_set) then
           call global%select_model (cmd%name, ufo=.true., ufo_path=cmd%ufo_path)
        else
           call global%select_model (cmd%name, ufo=.true.)
        end if
     else if (cmd%scheme /= "") then
        call global%select_model (cmd%name, cmd%scheme)
     else
        call global%select_model (cmd%name)
     end if
     if (.not. associated (global%model)) &
          call msg_fatal ("Switching to model '" &
          // char (cmd%name) // "': model not found")
   end subroutine cmd_model_execute
 
 @ %def cmd_model_execute
 @
 \subsubsection{Library configuration}
 We configure a process library that should hold the subsequently
 defined processes.  If the referenced library exists already, just
 make it the currently active one.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_library_t
      private
      type(string_t) :: name
    contains
    <<Commands: cmd library: TBP>>
   end type cmd_library_t
 
 @ %def cmd_library_t
 @ Output.
 <<Commands: cmd library: TBP>>=
   procedure :: write => cmd_library_write
 <<Commands: procedures>>=
   subroutine cmd_library_write (cmd, unit, indent)
     class(cmd_library_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit)
     call write_indent (u, indent)
     write (u, "(1x,A,1x,'""',A,'""')")  "library =", char (cmd%name)
   end subroutine cmd_library_write
 
 @ %def cmd_library_write
 @ Compile.  Get the library name.
 <<Commands: cmd library: TBP>>=
   procedure :: compile => cmd_library_compile
 <<Commands: procedures>>=
   subroutine cmd_library_compile (cmd, global)
     class(cmd_library_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_name
     pn_name => parse_node_get_sub_ptr (cmd%pn, 3)
     cmd%name = parse_node_get_string (pn_name)
   end subroutine cmd_library_compile
 
 @ %def cmd_library_compile
 @ Execute: Initialize a new library and push it on the library stack
 (if it does not yet exist).   Insert a pointer to the library into the
 global data record.  Then, try to load the library unless the
 [[rebuild]] flag is set.
 <<Commands: cmd library: TBP>>=
   procedure :: execute => cmd_library_execute
 <<Commands: procedures>>=
   subroutine cmd_library_execute (cmd, global)
     class(cmd_library_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     logical :: rebuild_library
     lib => global%prclib_stack%get_library_ptr (cmd%name)
     rebuild_library = &
          global%var_list%get_lval (var_str ("?rebuild_library"))
     if (.not. (associated (lib))) then
        allocate (lib_entry)
        call lib_entry%init (cmd%name)
        lib => lib_entry%process_library_t
        call global%add_prclib (lib_entry)
     else
        call global%update_prclib (lib)
     end if
     if (associated (lib) .and. .not. rebuild_library) then
        call lib%update_status (global%os_data)
     end if
   end subroutine cmd_library_execute
 
 @ %def cmd_library_execute
 @
 \subsubsection{Process configuration}
 We define a process-configuration command as a specific type.  The
 incoming and outgoing particles are given evaluation-trees which we
 transform to PDG-code arrays.  For transferring to \oMega, they are
 reconverted to strings.
 
 For the incoming particles, we store parse nodes individually.  We do
 not yet resolve the outgoing state, so we store just a single parse
 node.
 
 This also includes the choice of method for the corresponding process:
 [[omega]] for \oMega\ matrix elements as Fortran code, [[ovm]] for
 \oMega\ matrix elements as a bytecode virtual machine, [[test]] for
 special processes, [[unit_test]] for internal test matrix elements
 generated by \whizard, [[template]] and [[template_unity]] for test
 matrix elements generated by \whizard\ as Fortran code similar to the
 \oMega\ code. If the one-loop program (OLP) \gosam\ is linked, also
 matrix elements from there (at leading and next-to-leading order) can
 be generated via [[gosam]].
 <<Commands: types>>=
   type, extends (command_t) :: cmd_process_t
      private
      type(string_t) :: id
      integer :: n_in  = 0
      type(parse_node_p), dimension(:), allocatable :: pn_pdg_in
      type(parse_node_t), pointer :: pn_out => null ()
    contains
    <<Commands: cmd process: TBP>>
   end type cmd_process_t
 
 @ %def cmd_process_t
 @ Output.  The particle expressions are not resolved, so we just list the
 number of incoming particles.
 <<Commands: cmd process: TBP>>=
   procedure :: write => cmd_process_write
 <<Commands: procedures>>=
   subroutine cmd_process_write (cmd, unit, indent)
     class(cmd_process_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,A,A,I0,A)")  "process: ", char (cmd%id), " (", &
          size (cmd%pn_pdg_in), " -> X)"
     call cmd%write_options (u, indent)
   end subroutine cmd_process_write
 
 @ %def cmd_process_write
 @ Compile.  Find and assign the parse nodes.
 <<Commands: cmd process: TBP>>=
   procedure :: compile => cmd_process_compile
 <<Commands: procedures>>=
   subroutine cmd_process_compile (cmd, global)
     class(cmd_process_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_id, pn_in, pn_codes
     integer :: i
     pn_id => parse_node_get_sub_ptr (cmd%pn, 2)
     pn_in  => parse_node_get_next_ptr (pn_id, 2)
     cmd%pn_out => parse_node_get_next_ptr (pn_in, 2)
     cmd%pn_opt => parse_node_get_next_ptr (cmd%pn_out)
     call cmd%compile_options (global)
     cmd%id = parse_node_get_string (pn_id)
     cmd%n_in  = parse_node_get_n_sub (pn_in)
     pn_codes => parse_node_get_sub_ptr (pn_in)
     allocate (cmd%pn_pdg_in (cmd%n_in))
     do i = 1, cmd%n_in
        cmd%pn_pdg_in(i)%ptr => pn_codes
        pn_codes => parse_node_get_next_ptr (pn_codes)
     end do
   end subroutine cmd_process_compile
 
 @ %def cmd_process_compile
 @ Command execution.  Evaluate the subevents, transform PDG codes
 into strings, and add the current process configuration to the
 process library.
 
 The initial state will be unique (one or two particles).  For the final state,
 we allow for expressions.  The expressions will be expanded until we have a
 sum of final states.  Each distinct final state will get its own process
 component.
 
 To identify equivalent final states, we transform the final state into
 an array of PDG codes, which we sort and compare.  If a particle entry
 is actually a PDG array, only the first entry in the array is used for
 the comparison. The user should make sure that there is no overlap
 between different particles or arrays which would make the expansion
 ambiguous. 
 
 There are two possibilities that a process contains more than
 component: by an explicit component statement by the user for
 inclusive processes, or by having one process at NLO level. The first
 option is determined in the routine [[scan_components]], and
 determines [[n_components]].
 <<Commands: cmd process: TBP>>=
   procedure :: execute => cmd_process_execute
 <<Commands: procedures>>=
   subroutine cmd_process_execute (cmd, global)
     class(cmd_process_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(pdg_array_t) :: pdg_in, pdg_out
     type(pdg_array_t), dimension(:), allocatable :: pdg_out_tab
     type(string_t), dimension(:), allocatable :: prt_in
     type(string_t) :: prt_out, prt_out1
     type(process_configuration_t) :: prc_config
     type(prt_expr_t) :: prt_expr_out
     type(prt_spec_t), dimension(:), allocatable :: prt_spec_in
     type(prt_spec_t), dimension(:), allocatable :: prt_spec_out
     type(var_list_t), pointer :: var_list
     integer, dimension(:), allocatable :: pdg
     integer, dimension(:), allocatable :: i_term
     integer, dimension(:), allocatable :: nlo_comp
     integer :: i, j, n_in, n_out, n_terms, n_components
     logical :: nlo_fixed_order
     logical :: qcd_corr, qed_corr
     type(string_t), dimension(:), allocatable :: prt_in_nlo, prt_out_nlo
     type(radiation_generator_t) :: radiation_generator
     type(pdg_list_t) :: pl_in, pl_out, pl_excluded_gauge_splittings
     type(string_t) :: method, born_me_method, loop_me_method, &
          correlation_me_method, real_tree_me_method, dglap_me_method
     integer, dimension(:), allocatable :: i_list
     logical :: use_real_finite
     logical :: gks_active
     logical :: initial_state_colored
     integer :: comp_mult
     integer :: gks_multiplicity
     integer :: n_components_init
     integer :: alpha_power, alphas_power
     logical :: requires_soft_mismatch, requires_dglap_remnants
     if (debug_on) call msg_debug (D_CORE, "cmd_process_execute")
     var_list => cmd%local%get_var_list_ptr ()
 
     n_in = size (cmd%pn_pdg_in)
     allocate (prt_in (n_in), prt_spec_in (n_in))
     do i = 1, n_in
        pdg_in = &
             eval_pdg_array (cmd%pn_pdg_in(i)%ptr, var_list)
        prt_in(i) = make_flavor_string (pdg_in, cmd%local%model)
        prt_spec_in(i) = new_prt_spec (prt_in(i))
     end do
     call compile_prt_expr &
          (prt_expr_out, cmd%pn_out, var_list, cmd%local%model)
     call prt_expr_out%expand ()
     call scan_components ()
     allocate (nlo_comp (n_components))
     
     nlo_fixed_order = cmd%local%nlo_fixed_order
     gks_multiplicity = var_list%get_ival (var_str ('gks_multiplicity'))
     gks_active = gks_multiplicity > 2
     call check_for_nlo_corrections ()
 
     method = var_list%get_sval (var_str ("$method"))
     born_me_method = var_list%get_sval (var_str ("$born_me_method"))
     if (born_me_method == var_str (""))  born_me_method = method
     use_real_finite = var_list%get_lval (var_str ('?nlo_use_real_partition'))
     if (nlo_fixed_order) then
        real_tree_me_method = &
             var_list%get_sval (var_str ("$real_tree_me_method"))
        if (real_tree_me_method == var_str ("")) &
             real_tree_me_method = method
        loop_me_method = var_list%get_sval (var_str ("$loop_me_method"))
        if (loop_me_method == var_str ("")) &
             loop_me_method = method
        correlation_me_method = &
             var_list%get_sval (var_str ("$correlation_me_method"))
        if (correlation_me_method == var_str ("")) &
             correlation_me_method = method
        dglap_me_method = var_list%get_sval (var_str ("$dglap_me_method"))
        if (dglap_me_method == var_str ("")) &
             dglap_me_method = method
        call check_nlo_options (cmd%local)
     end if
 
     call determine_needed_components ()
     call prc_config%init (cmd%id, n_in, n_components_init, &
          cmd%local%model, cmd%local%var_list, &
          nlo_process = nlo_fixed_order)
 
     alpha_power = var_list%get_ival (var_str ("alpha_power"))
     alphas_power = var_list%get_ival (var_str ("alphas_power"))
     call prc_config%set_coupling_powers (alpha_power, alphas_power)
 
     call setup_components ()
     call prc_config%record (cmd%local)
 
   contains
 
   <<Commands: cmd process execute procedures>>
 
   end subroutine cmd_process_execute
 
 @ %def cmd_process_execute
 @
 <<Commands: cmd process execute procedures>>=
   elemental function is_threshold (method)
     logical :: is_threshold
     type(string_t), intent(in) :: method
     is_threshold = method == var_str ("threshold")
   end function is_threshold
 
   subroutine check_threshold_consistency ()
     if (nlo_fixed_order .and. is_threshold (born_me_method)) then
        if (.not. (is_threshold (real_tree_me_method) .and. is_threshold (loop_me_method) &
             .and. is_threshold (correlation_me_method))) then
             print *, 'born: ', char (born_me_method)
             print *, 'real: ', char (real_tree_me_method)
             print *, 'loop: ', char (loop_me_method)
             print *, 'correlation: ', char (correlation_me_method)
             call msg_fatal ("Inconsistent methods: All components need to be threshold")
        end if
     end if
   end subroutine check_threshold_consistency
 
 @ %def check_threshold_consistency
 <<Commands: cmd process execute procedures>>=
   subroutine check_for_nlo_corrections ()
     type(string_t) :: nlo_correction_type
     type(pdg_array_t), dimension(:), allocatable :: pdg
     if (nlo_fixed_order .or. gks_active) then
        nlo_correction_type = &
             var_list%get_sval (var_str ('$nlo_correction_type'))
        select case (char(nlo_correction_type))
        case ("QCD")
           qcd_corr = .true.; qed_corr = .false.
        case ("QED")
           qcd_corr = .false.; qed_corr = .true.
        case ("Full")
           qcd_corr =.true.; qed_corr = .true.
        case default
           call msg_fatal ("Invalid NLO correction type! " // &
                "Valid inputs are: QCD, QED, Full (default: QCD)")
        end select
        call check_for_excluded_gauge_boson_splitting_partners ()
        call setup_radiation_generator ()
     end if
     if (nlo_fixed_order) then
        call radiation_generator%find_splittings ()
        if (debug2_active (D_CORE)) then
           print *, ''
           print *, 'Found (pdg) splittings: '
           do i = 1, radiation_generator%if_table%get_length ()
              call radiation_generator%if_table%get_pdg_out (i, pdg)
              call pdg_array_write_set (pdg)
              print *, '----------------'
           end do
        end if
 
        nlo_fixed_order = radiation_generator%contains_emissions ()
        if (.not. nlo_fixed_order) call msg_warning &
             (arr = [var_str ("No NLO corrections found for process ") // &
             cmd%id // var_str("."), var_str ("Proceed with usual " // &
             "leading-order integration and simulation")])
     end if
   end subroutine check_for_nlo_corrections
 
 @ %def check_for_nlo_corrections
 @
 <<Commands: cmd process execute procedures>>=
   subroutine check_for_excluded_gauge_boson_splitting_partners ()
     type(string_t) :: str_excluded_partners
     type(string_t), dimension(:), allocatable :: excluded_partners
     type(pdg_list_t) :: pl_tmp, pl_anti
     integer :: i, n_anti
     str_excluded_partners = var_list%get_sval &
          (var_str ("$exclude_gauge_splittings"))
     if (str_excluded_partners == "") then
        return
     else
        call split_string (str_excluded_partners, &
             var_str (":"), excluded_partners)
        call pl_tmp%init (size (excluded_partners))
        do i = 1, size (excluded_partners)
           call pl_tmp%set (i, &
                cmd%local%model%get_pdg (excluded_partners(i), .true.))
        end do
        call pl_tmp%create_antiparticles (pl_anti, n_anti)
        call pl_excluded_gauge_splittings%init (pl_tmp%get_size () + n_anti)
        do i = 1, pl_tmp%get_size ()
           call pl_excluded_gauge_splittings%set (i, pl_tmp%get(i))
        end do
        do i = 1, n_anti
           j = i + pl_tmp%get_size ()
           call pl_excluded_gauge_splittings%set (j, pl_anti%get(i))
        end do
     end if
   end subroutine check_for_excluded_gauge_boson_splitting_partners
 
 @ %def check_for_excluded_gauge_boson_splitting_partners
 @
 <<Commands: cmd process execute procedures>>=
   subroutine determine_needed_components ()
     type(string_t) :: fks_method
     comp_mult = 1
     if (nlo_fixed_order) then
        fks_method = var_list%get_sval (var_str ('$fks_mapping_type'))
        call check_threshold_consistency ()
        requires_soft_mismatch = fks_method == var_str ('resonances')
        comp_mult = needed_extra_components (requires_dglap_remnants, &
             use_real_finite, requires_soft_mismatch)
        allocate (i_list (comp_mult))
     else if (gks_active) then
        call radiation_generator%generate_multiple &
             (gks_multiplicity, cmd%local%model)
        comp_mult = radiation_generator%get_n_gks_states () + 1
     end if
     n_components_init = n_components * comp_mult
   end subroutine determine_needed_components
 
 @ %def determine_needed_components
 @
 <<Commands: cmd process execute procedures>>=
   subroutine setup_radiation_generator ()
     call split_prt (prt_spec_in, n_in, pl_in)
     call split_prt (prt_spec_out, n_out, pl_out)
     call radiation_generator%init (pl_in, pl_out, &
          pl_excluded_gauge_splittings, qcd = qcd_corr, qed = qed_corr)
     call radiation_generator%set_n (n_in, n_out, 0)
     initial_state_colored = pdg_in%has_colored_particles ()
     if ((n_in == 2 .and. initial_state_colored) .or. qed_corr) then
         requires_dglap_remnants = n_in == 2 .and. initial_state_colored
         call radiation_generator%set_initial_state_emissions ()
     else
        requires_dglap_remnants = .false.
     end if
     call radiation_generator%set_constraints (.false., .false., .true., .true.)
     call radiation_generator%setup_if_table (cmd%local%model)
   end subroutine setup_radiation_generator
 
 @ %def setup_radiation_generator
 @
 <<Commands: cmd process execute procedures>>=
   subroutine scan_components ()
     n_terms = prt_expr_out%get_n_terms ()
     allocate (pdg_out_tab (n_terms))
     allocate (i_term (n_terms), source = 0)
     n_components = 0
     SCAN: do i = 1, n_terms
        if (allocated (pdg))  deallocate (pdg)
        call prt_expr_out%term_to_array (prt_spec_out, i)
        n_out = size (prt_spec_out)
        allocate (pdg (n_out))
        do j = 1, n_out
           prt_out = prt_spec_out(j)%to_string ()
           call split (prt_out, prt_out1, ":")
           pdg(j) = cmd%local%model%get_pdg (prt_out1)
        end do
        pdg_out = sort (pdg)
        do j = 1, n_components
           if (pdg_out == pdg_out_tab(j))  cycle SCAN
        end do
        n_components = n_components + 1
        i_term(n_components) = i
        pdg_out_tab(n_components) = pdg_out
     end do SCAN
   end subroutine scan_components
 
 @
 <<Commands: cmd process execute procedures>>=
   subroutine split_prt (prt, n_out, pl)
     type(prt_spec_t), intent(in), dimension(:), allocatable :: prt
     integer, intent(in) :: n_out
     type(pdg_list_t), intent(out) :: pl
     type(pdg_array_t) :: pdg
     type(string_t) :: prt_string, prt_tmp
     integer, parameter :: max_particle_number = 25
     integer, dimension(max_particle_number) :: i_particle
     integer :: i, j, n
     i_particle = 0
     call pl%init (n_out)
     do i = 1, n_out
        n = 1
        prt_string = prt(i)%to_string ()
        do
          call split (prt_string, prt_tmp, ":")
          if (prt_tmp /= "") then
            i_particle(n) = cmd%local%model%get_pdg (prt_tmp)
            n = n + 1
          else
            exit
          end if
        end do
        call pdg_array_init (pdg, n - 1)
        do j = 1, n - 1
          call pdg%set (j, i_particle(j))
        end do
        call pl%set (i, pdg)
        call pdg_array_delete (pdg)
     end do
   end subroutine split_prt
 
 @ %def split_prt
 @
 <<Commands: cmd process execute procedures>>=
   subroutine setup_components()
     integer :: k, i_comp, add_index
     i_comp = 0
     add_index = 0
     if (debug_on) call msg_debug (D_CORE, "setup_components")
     do i = 1, n_components
        call prt_expr_out%term_to_array (prt_spec_out, i_term(i))
        if (nlo_fixed_order) then
           associate (selected_nlo_parts => cmd%local%selected_nlo_parts)
              if (debug_on) call msg_debug (D_CORE, "Setting up this NLO component:", &
                   i_comp + 1)
              call prc_config%setup_component (i_comp + 1, &
                   prt_spec_in, prt_spec_out, &
                   cmd%local%model, var_list, BORN, &
                   can_be_integrated = selected_nlo_parts (BORN))
              call radiation_generator%generate_real_particle_strings &
                   (prt_in_nlo, prt_out_nlo)
              if (debug_on) call msg_debug (D_CORE, "Setting up this NLO component:", &
                   i_comp + 2)
              call prc_config%setup_component (i_comp + 2, &
                   new_prt_spec (prt_in_nlo), new_prt_spec (prt_out_nlo), &
                   cmd%local%model, var_list, NLO_REAL, &
                   can_be_integrated = selected_nlo_parts (NLO_REAL))
              if (debug_on) call msg_debug (D_CORE, "Setting up this NLO component:", &
                   i_comp + 3)
              call prc_config%setup_component (i_comp + 3, &
                   prt_spec_in, prt_spec_out, &
                   cmd%local%model, var_list, NLO_VIRTUAL, &
                   can_be_integrated = selected_nlo_parts (NLO_VIRTUAL))
              if (debug_on) call msg_debug (D_CORE, "Setting up this NLO component:", &
                   i_comp + 4)
              call prc_config%setup_component (i_comp + 4, &
                   prt_spec_in, prt_spec_out, &
                   cmd%local%model, var_list, NLO_SUBTRACTION, &
                   can_be_integrated = selected_nlo_parts (NLO_SUBTRACTION))
              do k = 1, 4
                 i_list(k) = i_comp + k
              end do
              if (requires_dglap_remnants) then
                 if (debug_on) call msg_debug (D_CORE, "Setting up this NLO component:", &
                      i_comp + 5)
                 call prc_config%setup_component (i_comp + 5, &
                      prt_spec_in, prt_spec_out, &
                      cmd%local%model, var_list, NLO_DGLAP, &
                      can_be_integrated = selected_nlo_parts (NLO_DGLAP))
                 i_list(5) = i_comp + 5
                 add_index = add_index + 1
              end if
              if (use_real_finite) then
                 if (debug_on) call msg_debug (D_CORE, "Setting up this NLO component:", &
                      i_comp + 5 + add_index)
                 call prc_config%setup_component (i_comp + 5 + add_index, &
                      new_prt_spec (prt_in_nlo), new_prt_spec (prt_out_nlo), &
                      cmd%local%model, var_list, NLO_REAL, &
                      can_be_integrated = selected_nlo_parts (NLO_REAL))
                 i_list(5 + add_index) = i_comp + 5 + add_index
                 add_index = add_index + 1
              end if
              if (requires_soft_mismatch) then
                 if (debug_on) call msg_debug (D_CORE, "Setting up this NLO component:", &
                      i_comp + 5 + add_index)
                 call prc_config%setup_component (i_comp + 5 + add_index, &
                    prt_spec_in, prt_spec_out, &
                    cmd%local%model, var_list, NLO_MISMATCH, &
                    can_be_integrated = selected_nlo_parts (NLO_MISMATCH))
                 i_list(5 + add_index) = i_comp + 5 + add_index
              end if
              call prc_config%set_component_associations (i_list, &
                   requires_dglap_remnants, use_real_finite, &
                   requires_soft_mismatch)
           end associate
        else if (gks_active) then
           call prc_config%setup_component (i_comp + 1, prt_spec_in, &
                prt_spec_out, cmd%local%model, var_list, BORN, &
                can_be_integrated = .true.)
           call radiation_generator%reset_queue ()
           do j = 1, comp_mult
              prt_out_nlo =  radiation_generator%get_next_state ()
              call prc_config%setup_component (i_comp + 1 + j, &
                 new_prt_spec (prt_in), new_prt_spec (prt_out_nlo), &
                 cmd%local%model, var_list, GKS, can_be_integrated = .false.)
           end do
        else
           call prc_config%setup_component (i, &
                prt_spec_in, prt_spec_out, &
                cmd%local%model, var_list, can_be_integrated = .true.)
        end if
        i_comp = i_comp + comp_mult
     end do
   end subroutine setup_components
 
 @
 @ These three functions should be bundled with the logicals they depend
 on into an object (the pcm?).
 <<Commands: procedures>>=
   subroutine check_nlo_options (local)
     type(rt_data_t), intent(in) :: local
     type(var_list_t), pointer :: var_list => null ()
     logical :: nlo, combined, powheg
     logical :: case_lo_but_any_other
     logical :: case_nlo_powheg_but_not_combined
     logical :: vamp_equivalences_enabled
     logical :: fixed_order_nlo_events
     var_list => local%get_var_list_ptr ()
     nlo = local%nlo_fixed_order
     combined = var_list%get_lval (var_str ('?combined_nlo_integration'))
     powheg = var_list%get_lval (var_str ('?powheg_matching'))
     case_lo_but_any_other = .not. nlo .and. any ([combined, powheg])
     case_nlo_powheg_but_not_combined = &
          nlo .and. powheg .and. .not. combined
     if (case_lo_but_any_other) then
        call msg_fatal ("Option mismatch: Leading order process is selected &
             &but either powheg_matching or combined_nlo_integration &
             &is set to true.")
     else if (case_nlo_powheg_but_not_combined) then
        call msg_fatal ("POWHEG requires the 'combined_nlo_integration'-option &
             &to be set to true.")
     end if
     fixed_order_nlo_events = &
          var_list%get_lval (var_str ('?fixed_order_nlo_events'))
     if (fixed_order_nlo_events .and. .not. combined .and. &
          all (local%selected_nlo_parts)) &
        call msg_fatal ("Option mismatch: Fixed order NLO events of the full ", &
             [var_str ("process are requested, but ?combined_nlo_integration"), &
             var_str ("is false. You can either switch to the combined NLO"), &
             var_str ("integration mode or choose one individual NLO component"), &
             var_str ("to generate events with.")])
     vamp_equivalences_enabled = var_list%get_lval &
          (var_str ('?use_vamp_equivalences'))
     if (nlo .and. vamp_equivalences_enabled) &
          call msg_warning ("You have not disabled VAMP equivalences. ", &
               [var_str ("   Note that they are automatically switched off "), &
                var_str ("   for NLO calculations.")])
   end subroutine check_nlo_options
 
 @ %def check_nlo_options
 @ There are four components for a general NLO process, namely Born,
 real, virtual and subtraction. There will be additional components for
 DGLAP remnant, in case real contributions are split into singular and
 finite pieces, and for resonance-aware FKS subtraction for the needed
 soft mismatch component.
 <<Commands: procedures>>=
   pure function needed_extra_components (requires_dglap_remnant, &
          use_real_finite, requires_soft_mismatch) result (n)
     integer :: n
     logical, intent(in) :: requires_dglap_remnant, &
          use_real_finite, requires_soft_mismatch
     n = 4
     if (requires_dglap_remnant)  n = n + 1
     if (use_real_finite)  n = n + 1
     if (requires_soft_mismatch)  n = n + 1
   end function needed_extra_components
 
 @ %def needed_extra_components
 @ This is a method of the eval tree, but cannot be coded inside the
 [[expressions]] module since it uses the [[model]] and [[flv]] types
 which are not available there.
 <<Commands: procedures>>=
   function make_flavor_string (aval, model) result (prt)
     type(string_t) :: prt
     type(pdg_array_t), intent(in) :: aval
     type(model_t), intent(in), target :: model
     integer, dimension(:), allocatable :: pdg
     type(flavor_t), dimension(:), allocatable :: flv
     integer :: i
     pdg = aval
     allocate (flv (size (pdg)))
     call flv%init (pdg, model)
     if (size (pdg) /= 0) then
        prt = flv(1)%get_name ()
        do i = 2, size (flv)
           prt = prt // ":" // flv(i)%get_name ()
        end do
     else
        prt = "?"
     end if
   end function make_flavor_string
 
 @ %def make_flavor_string
 @ Create a pdg array from a particle-specification array
 <<Commands: procedures>>=
   function make_pdg_array (prt, model) result (pdg_array)
     type(prt_spec_t), intent(in), dimension(:) :: prt
     type(model_t), intent(in) :: model
     integer, dimension(:), allocatable :: aval
     type(pdg_array_t) :: pdg_array
     type(flavor_t) :: flv
     integer :: k
     allocate (aval (size (prt)))
     do k = 1, size (prt)
       call flv%init (prt(k)%to_string (), model)
       aval (k) = flv%get_pdg ()
     end do
     pdg_array = aval
   end function make_pdg_array
 
 @ %def make_pdg_array
 @ Compile a (possible nested) expression, to obtain a
 particle-specifier expression which we can process further.
 <<Commands: procedures>>=
   recursive subroutine compile_prt_expr (prt_expr, pn, var_list, model)
     type(prt_expr_t), intent(out) :: prt_expr
     type(parse_node_t), intent(in), target :: pn
     type(var_list_t), intent(in), target :: var_list
     type(model_t), intent(in), target :: model
     type(parse_node_t), pointer :: pn_entry, pn_term, pn_addition
     type(pdg_array_t) :: pdg
     type(string_t) :: prt_string
     integer :: n_entry, n_term, i
     select case (char (parse_node_get_rule_key (pn)))
     case ("prt_state_list")
        n_entry = parse_node_get_n_sub (pn)
        pn_entry => parse_node_get_sub_ptr (pn)
        if (n_entry == 1) then
           call compile_prt_expr (prt_expr, pn_entry, var_list, model)
        else
           call prt_expr%init_list (n_entry)
           select type (x => prt_expr%x)
           type is (prt_spec_list_t)
              do i = 1, n_entry
                 call compile_prt_expr (x%expr(i), pn_entry, var_list, model)
                 pn_entry => parse_node_get_next_ptr (pn_entry)
              end do
           end select
        end if
     case ("prt_state_sum")
        n_term = parse_node_get_n_sub (pn)
        pn_term => parse_node_get_sub_ptr (pn)
        pn_addition => pn_term
        if (n_term == 1) then
           call compile_prt_expr (prt_expr, pn_term, var_list, model)
        else
           call prt_expr%init_sum (n_term)
           select type (x => prt_expr%x)
           type is (prt_spec_sum_t)
              do i = 1, n_term
                 call compile_prt_expr (x%expr(i), pn_term, var_list, model)
                 pn_addition => parse_node_get_next_ptr (pn_addition)
                 if (associated (pn_addition)) &
                      pn_term => parse_node_get_sub_ptr (pn_addition, 2)
              end do
           end select
        end if
     case ("cexpr")
        pdg = eval_pdg_array (pn, var_list)
        prt_string = make_flavor_string (pdg, model)
        call prt_expr%init_spec (new_prt_spec (prt_string))
     case default
        call parse_node_write_rec (pn)
        call msg_bug ("compile prt expr: impossible syntax rule")
     end select
   end subroutine compile_prt_expr
 
 @ %def compile_prt_expr
 @
 \subsubsection{Initiating a NLO calculation}
 <<Commands: types>>=
   type, extends (command_t) :: cmd_nlo_t
     private
     integer, dimension(:), allocatable :: nlo_component
   contains
     <<Commands: cmd nlo: TBP>>
   end type cmd_nlo_t
 
 @ %def cmd_nlo_t
 @
 <<Commands: cmd nlo: TBP>>=
   procedure :: write => cmd_nlo_write
 <<Commands: procedures>>=
   subroutine cmd_nlo_write (cmd, unit, indent)
     class(cmd_nlo_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
   end subroutine cmd_nlo_write
 
 @ %def cmd_nlo_write
 @ As it is, the NLO calculation is switched on by putting {nlo} behind the process definition. This should be made nicer in the future.
 <<Commands: cmd nlo: TBP>>=
   procedure :: compile => cmd_nlo_compile
 <<Commands: procedures>>=
   subroutine cmd_nlo_compile (cmd, global)
     class(cmd_nlo_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg, pn_comp
     integer :: i, n_comp
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 3)
     if (associated (pn_arg)) then
        n_comp = parse_node_get_n_sub (pn_arg)
        allocate (cmd%nlo_component (n_comp))
        pn_comp => parse_node_get_sub_ptr (pn_arg)
        i = 0
        do while (associated (pn_comp))
           i = i + 1
           cmd%nlo_component(i) = component_status &
                (parse_node_get_rule_key (pn_comp))
           pn_comp => parse_node_get_next_ptr (pn_comp)
        end do
     else
        allocate (cmd%nlo_component (0))
     end if
   end subroutine cmd_nlo_compile
 
 @ %def cmd_nlo_compile
 @
 <<Commands: cmd nlo: TBP>>=
   procedure :: execute => cmd_nlo_execute
 <<Commands: procedures>>=
   subroutine cmd_nlo_execute (cmd, global)
     class(cmd_nlo_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(string_t) :: string
     integer :: n, i, j
     logical, dimension(0:5) :: selected_nlo_parts
     if (debug_on) call msg_debug (D_CORE, "cmd_nlo_execute")
     selected_nlo_parts = .false.
     if (allocated (cmd%nlo_component)) then
        n = size (cmd%nlo_component)
     else
        n = 0
     end if
     do i = 1, n
        select case (cmd%nlo_component (i))
        case (BORN, NLO_VIRTUAL, NLO_MISMATCH, NLO_DGLAP, NLO_REAL)
           selected_nlo_parts(cmd%nlo_component (i)) = .true.
        case (NLO_FULL)
           selected_nlo_parts = .true.
           selected_nlo_parts (NLO_SUBTRACTION) = .false.
        case default
           string = var_str ("")
           do j = BORN, NLO_DGLAP
              string = string // component_status (j) // ", "
           end do
           string = string // component_status (NLO_FULL)
           call msg_fatal ("Invalid NLO mode. Valid modes are: " // &
                char (string))
        end select
     end do
     global%nlo_fixed_order = any (selected_nlo_parts)
     global%selected_nlo_parts = selected_nlo_parts
     allocate (global%nlo_component (size (cmd%nlo_component)))
     global%nlo_component = cmd%nlo_component
   end subroutine cmd_nlo_execute
 
 @ %def cmd_nlo_execute
 @
 \subsubsection{Process compilation}
 <<Commands: types>>=
   type, extends (command_t) :: cmd_compile_t
      private
      type(string_t), dimension(:), allocatable :: libname
      logical :: make_executable = .false.
      type(string_t) :: exec_name
    contains
    <<Commands: cmd compile: TBP>>
   end type cmd_compile_t
 
 @ %def cmd_compile_t
 @ Output: list all libraries to be compiled.
 <<Commands: cmd compile: TBP>>=
   procedure :: write => cmd_compile_write
 <<Commands: procedures>>=
   subroutine cmd_compile_write (cmd, unit, indent)
     class(cmd_compile_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, i
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)", advance="no")  "compile ("
     if (allocated (cmd%libname)) then
        do i = 1, size (cmd%libname)
           if (i > 1)  write (u, "(A,1x)", advance="no")  ","
           write (u, "('""',A,'""')", advance="no")  char (cmd%libname(i))
        end do
     end if
     write (u, "(A)")  ")"
   end subroutine cmd_compile_write
 
 @ %def cmd_compile_write
 @ Compile the libraries specified in the argument.  If the argument is
 empty, compile all libraries which can be found in the process library stack.
 <<Commands: cmd compile: TBP>>=
   procedure :: compile => cmd_compile_compile
 <<Commands: procedures>>=
   subroutine cmd_compile_compile (cmd, global)
     class(cmd_compile_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_cmd, pn_clause, pn_arg, pn_lib
     type(parse_node_t), pointer :: pn_exec_name_spec, pn_exec_name
     integer :: n_lib, i
     pn_cmd => parse_node_get_sub_ptr (cmd%pn)
     pn_clause => parse_node_get_sub_ptr (pn_cmd)
     pn_exec_name_spec => parse_node_get_sub_ptr (pn_clause, 2)
     if (associated (pn_exec_name_spec)) then
        pn_exec_name => parse_node_get_sub_ptr (pn_exec_name_spec, 2)
     else
        pn_exec_name => null ()
     end if
     pn_arg => parse_node_get_next_ptr (pn_clause)
     cmd%pn_opt => parse_node_get_next_ptr (pn_cmd)
     call cmd%compile_options (global)
     if (associated (pn_arg)) then
        n_lib = parse_node_get_n_sub (pn_arg)
     else
        n_lib = 0
     end if
     if (n_lib > 0) then
        allocate (cmd%libname (n_lib))
        pn_lib => parse_node_get_sub_ptr (pn_arg)
        do i = 1, n_lib
           cmd%libname(i) = parse_node_get_string (pn_lib)
           pn_lib => parse_node_get_next_ptr (pn_lib)
        end do
     end if
     if (associated (pn_exec_name)) then
        cmd%make_executable = .true.
        cmd%exec_name = parse_node_get_string (pn_exec_name)
     end if
   end subroutine cmd_compile_compile
 
 @ %def cmd_compile_compile
 @ Command execution.  Generate code, write driver, compile and link.
 Do this for all libraries in the list.
 
 If no library names have been given and stored while compiling this
 command, we collect all libraries from the current stack and compile
 those.
 
 As a bonus, a compiled library may be able to spawn new process
 libraries.  For instance, a processes may ask for a set of resonant
 subprocesses which go into their own library, but this can be
 determined only after the process is available as a compiled object.
 Therefore, the compilation loop is implemented as a recursive internal
 subroutine.
 
 We can compile static libraries (which actually just loads them).  However, we
 can't incorporate in a generated executable.
 <<Commands: cmd compile: TBP>>=
   procedure :: execute => cmd_compile_execute
 <<Commands: procedures>>=
   subroutine cmd_compile_execute (cmd, global)
     class(cmd_compile_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(string_t), dimension(:), allocatable :: libname, libname_static
     integer :: i, n_lib
     <<Commands: cmd compile execute: variables>>
     <<Commands: cmd compile execute: init>>
     if (allocated (cmd%libname)) then
        allocate (libname (size (cmd%libname)))
        libname = cmd%libname
     else
        call cmd%local%prclib_stack%get_names (libname)
     end if
     n_lib = size (libname)
     if (cmd%make_executable) then
        call get_prclib_static (libname_static)
        do i = 1, n_lib
           if (any (libname_static == libname(i))) then
              call msg_fatal ("Compile: can't include static library '" &
                   // char (libname(i)) // "'")
           end if
        end do
        call compile_executable (cmd%exec_name, libname, cmd%local)
     else
        call compile_libraries (libname)
        call global%update_prclib &
             (global%prclib_stack%get_library_ptr (libname(n_lib)))
     end if
     <<Commands: cmd compile execute: end init>>
   contains
     recursive subroutine compile_libraries (libname)
       type(string_t), dimension(:), intent(in) :: libname
       integer :: i
       type(string_t), dimension(:), allocatable :: libname_extra
       type(process_library_t), pointer :: lib_saved
       do i = 1, size (libname)
          call compile_library (libname(i), cmd%local)
          lib_saved => global%prclib
          call spawn_extra_libraries &
               (libname(i), cmd%local, global, libname_extra)
          call compile_libraries (libname_extra)
          call global%update_prclib (lib_saved)
       end do
     end subroutine compile_libraries
   end subroutine cmd_compile_execute
 
 @ %def cmd_compile_execute
 <<Commands: cmd compile execute: variables>>=
 @
 <<Commands: cmd compile execute: init>>=
 @
 <<Commands: cmd compile execute: end init>>=
 @
 @ The parallelization leads to undefined behavior while writing simultaneously to one file.
 The master worker has to initialize single-handed the corresponding library files.
 The slave worker will wait with a blocking [[MPI_BCAST]] until they receive a logical flag.
 <<MPI: Commands: cmd compile execute: variables>>=
   logical :: compile_init
   integer :: rank, n_size
 <<MPI: Commands: cmd compile execute: init>>=
   if (debug_on) call msg_debug (D_MPI, "cmd_compile_execute")
   compile_init = .false.
   call mpi_get_comm_id (n_size, rank)
   if (debug_on) call msg_debug (D_MPI, "n_size", rank)
   if (debug_on) call msg_debug (D_MPI, "rank", rank)
   if (rank /= 0) then
      if (debug_on) call msg_debug (D_MPI, "wait for master")
      call MPI_bcast (compile_init, 1, MPI_LOGICAL, 0, MPI_COMM_WORLD)
   else
      compile_init = .true.
   end if
 
   if (compile_init) then
 <<MPI: Commands: cmd compile execute: end init>>=
   if (rank == 0) then
      if (debug_on) call msg_debug (D_MPI, "load slaves")
      call MPI_bcast (compile_init, 1, MPI_LOGICAL, 0, MPI_COMM_WORLD)
   end if
 end if
 call MPI_barrier (MPI_COMM_WORLD)
 @ %def cmd_compile_execute_mpi
 @
 This is the interface to the external procedure which returns the
 names of all static libraries which are part of the executable.  (The
 default is none.)  The routine must allocate the array.
 <<Commands: public>>=
   public :: get_prclib_static
 <<Commands: interfaces>>=
   interface
      subroutine get_prclib_static (libname)
        import
        type(string_t), dimension(:), intent(inout), allocatable :: libname
      end subroutine get_prclib_static
   end interface
 
 @ %def get_prclib_static
 @
 Spawn extra libraries.  We can ask the processes within a compiled
 library, which we have available at this point, whether they need additional
 processes which should go into their own libraries.
 
 The current implementation only concerns resonant subprocesses.
 
 Note that the libraries should be created (source code), but not be
 compiled here.  This is done afterwards.
 <<Commands: procedures>>=
   subroutine spawn_extra_libraries (libname, local, global, libname_extra)
     type(string_t), intent(in) :: libname
     type(rt_data_t), intent(inout), target :: local
     type(rt_data_t), intent(inout), target :: global
     type(string_t), dimension(:), allocatable, intent(out) :: libname_extra
     type(string_t), dimension(:), allocatable :: libname_res
     allocate (libname_extra (0))
     call spawn_resonant_subprocess_libraries &
          (libname, local, global, libname_res)
     if (allocated (libname_res))  libname_extra = [libname_extra, libname_res]
   end subroutine spawn_extra_libraries
 
 @ %def spawn_extra_libraries
 @
 \subsubsection{Execute a shell command}
 The argument is a string expression.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_exec_t
      private
      type(parse_node_t), pointer :: pn_command => null ()
    contains
    <<Commands: cmd exec: TBP>>
   end type cmd_exec_t
 
 @ %def cmd_exec_t
 @ Simply tell the status.
 <<Commands: cmd exec: TBP>>=
   procedure :: write => cmd_exec_write
 <<Commands: procedures>>=
   subroutine cmd_exec_write (cmd, unit, indent)
     class(cmd_exec_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     if (associated (cmd%pn_command)) then
        write (u, "(1x,A)")  "exec: [command associated]"
     else
        write (u, "(1x,A)")  "exec: [undefined]"
     end if
   end subroutine cmd_exec_write
 
 @ %def cmd_exec_write
 @ Compile the exec command.
 <<Commands: cmd exec: TBP>>=
   procedure :: compile => cmd_exec_compile
 <<Commands: procedures>>=
   subroutine cmd_exec_compile (cmd, global)
     class(cmd_exec_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg, pn_command
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 2)
     pn_command => parse_node_get_sub_ptr (pn_arg)
     cmd%pn_command => pn_command
   end subroutine cmd_exec_compile
 
 @ %def cmd_exec_compile
 @ Execute the specified shell command.
 <<Commands: cmd exec: TBP>>=
   procedure :: execute => cmd_exec_execute
 <<Commands: procedures>>=
   subroutine cmd_exec_execute (cmd, global)
     class(cmd_exec_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(string_t) :: command
     logical :: is_known
     integer :: status
     command = eval_string (cmd%pn_command, global%var_list, is_known=is_known)
     if (is_known) then
        if (command /= "") then
           call os_system_call (command, status, verbose=.true.)
           if (status /= 0) then
              write (msg_buffer, "(A,I0)")  "Return code = ", status
              call msg_message ()
              call msg_error ("System command returned with nonzero status code")
           end if
        end if
     end if
   end subroutine cmd_exec_execute
 
 @ %def cmd_exec_execute
 @
 \subsubsection{Variable declaration}
 A variable can have various types.  Hold the definition as an eval
 tree.
 
 There are intrinsic variables, user variables, and model variables.
 The latter are further divided in independent variables and dependent
 variables.
 
 Regarding model variables: When dealing with them, we always look at
 two variable lists in parallel.  The global (or local) variable list
 contains the user-visible values.  It includes variables that
 correspond to variables in the current model's list.  These, in turn,
 are pointers to the model's parameter list, so the model is always in
 sync, internally.  To keep the global variable list in sync with the
 model, the global variables carry the [[is_copy]] property and contain
 a separate pointer to the model variable.  (The pointer is reassigned
 whenever the model changes.)  Modifying the global variable changes
 two values simultaneously: the visible value and the model variable,
 via this extra pointer.  After each modification, we update dependent
 parameters in the model variable list and re-synchronize the global
 variable list (again, using these pointers) with the model variable
 this.  In the last step, modifications in the derived parameters
 become visible.
 
 When we integrate a process, we capture the current variable list of
 the current model in a separate model instance, which is stored in the
 process object.  Thus, the model parameters associated to this process
 at this time are preserved for the lifetime of the process object.
 
 When we generate or rescan events, we can again capture a local model
 variable list in a model instance.  This allows us to reweight event
 by event with different parameter sets simultaneously.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_var_t
      private
      type(string_t) :: name
      integer :: type = V_NONE
      type(parse_node_t), pointer :: pn_value => null ()
      logical :: is_intrinsic = .false.
      logical :: is_model_var = .false.
    contains
    <<Commands: cmd var: TBP>>
   end type cmd_var_t
 
 @ %def cmd_var_t
 @ Output.  We know name, type, and properties, but not the value.
 <<Commands: cmd var: TBP>>=
   procedure :: write => cmd_var_write
 <<Commands: procedures>>=
   subroutine cmd_var_write (cmd, unit, indent)
     class(cmd_var_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,A,A)", advance="no")  "var: ", char (cmd%name), " ("
     select case (cmd%type)
     case (V_NONE)
        write (u, "(A)", advance="no")  "[unknown]"
     case (V_LOG)
        write (u, "(A)", advance="no")  "logical"
     case (V_INT)
        write (u, "(A)", advance="no")  "int"
     case (V_REAL)
        write (u, "(A)", advance="no")  "real"
     case (V_CMPLX)
        write (u, "(A)", advance="no")  "complex"
     case (V_STR)
        write (u, "(A)", advance="no")  "string"
     case (V_PDG)
        write (u, "(A)", advance="no")  "alias"
     end select
     if (cmd%is_intrinsic) then
        write (u, "(A)", advance="no")  ", intrinsic"
     end if
     if (cmd%is_model_var) then
        write (u, "(A)", advance="no")  ", model"
     end if
     write (u, "(A)")  ")"
   end subroutine cmd_var_write
 
 @ %def cmd_var_write
 @ Compile the lhs and determine the variable name and type.  Check whether
 this variable can be created or modified as requested, and append the value to
 the variable list, if appropriate.  The value is initially undefined.
 The rhs is assigned to a pointer, to be compiled and evaluated when the
 command is executed.
 <<Commands: cmd var: TBP>>=
   procedure :: compile => cmd_var_compile
 <<Commands: procedures>>=
   subroutine cmd_var_compile (cmd, global)
     class(cmd_var_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_var, pn_name
     type(parse_node_t), pointer :: pn_result, pn_proc
     type(string_t) :: var_name
     type(var_list_t), pointer :: model_vars
     integer :: type
     logical :: new
     pn_result => null ()
     new = .false.
     select case (char (parse_node_get_rule_key (cmd%pn)))
     case ("cmd_log_decl");    type = V_LOG
        pn_var => parse_node_get_sub_ptr (cmd%pn, 2)
        if (.not. associated (pn_var)) then   ! handle masked syntax error
           cmd%type = V_NONE; return
        end if
        pn_name => parse_node_get_sub_ptr (pn_var, 2)
        new = .true.
     case ("cmd_log");         type = V_LOG
        pn_name => parse_node_get_sub_ptr (cmd%pn, 2)
     case ("cmd_int");         type = V_INT
        pn_name => parse_node_get_sub_ptr (cmd%pn, 2)
        new = .true.
     case ("cmd_real");        type = V_REAL
        pn_name => parse_node_get_sub_ptr (cmd%pn, 2)
        new = .true.
     case ("cmd_complex");       type = V_CMPLX
        pn_name => parse_node_get_sub_ptr (cmd%pn, 2)
        new = .true.
     case ("cmd_num");         type = V_NONE
        pn_name => parse_node_get_sub_ptr (cmd%pn)
     case ("cmd_string_decl"); type = V_STR
        pn_var => parse_node_get_sub_ptr (cmd%pn, 2)
        if (.not. associated (pn_var)) then   ! handle masked syntax error
           cmd%type = V_NONE; return
        end if
        pn_name => parse_node_get_sub_ptr (pn_var, 2)
        new = .true.
     case ("cmd_string");      type = V_STR
        pn_name => parse_node_get_sub_ptr (cmd%pn, 2)
     case ("cmd_alias");       type = V_PDG
        pn_name => parse_node_get_sub_ptr (cmd%pn, 2)
        new = .true.
     case ("cmd_result");      type = V_REAL
        pn_name => parse_node_get_sub_ptr (cmd%pn)
        pn_result => parse_node_get_sub_ptr (pn_name)
        pn_proc => parse_node_get_next_ptr (pn_result)
     case default
        call parse_node_mismatch &
             ("logical|int|real|complex|?|$|alias|var_name", cmd%pn)  ! $
     end select
     if (.not. associated (pn_name)) then   ! handle masked syntax error
        cmd%type = V_NONE; return
     end if
     if (.not. associated (pn_result)) then
        var_name = parse_node_get_string (pn_name)
     else
        var_name = parse_node_get_key (pn_result) &
             // "(" // parse_node_get_string (pn_proc) // ")"
     end if
     select case (type)
     case (V_LOG);  var_name = "?" // var_name
     case (V_STR);  var_name = "$" // var_name    ! $
     end select
     if (associated (global%model)) then
        model_vars => global%model%get_var_list_ptr ()
     else
        model_vars => null ()
     end if
     call var_list_check_observable (global%var_list, var_name, type)
     call var_list_check_result_var (global%var_list, var_name, type)
     call global%var_list%check_user_var (var_name, type, new)
     cmd%name = var_name
     cmd%pn_value => parse_node_get_next_ptr (pn_name, 2)
     if (global%var_list%contains (cmd%name, follow_link = .false.)) then
        ! local variable
        cmd%is_intrinsic = &
             global%var_list%is_intrinsic (cmd%name, follow_link = .false.)
        cmd%type = &
             global%var_list%get_type (cmd%name, follow_link = .false.)
     else
        if (new)  cmd%type = type
        if (global%var_list%contains (cmd%name, follow_link = .true.)) then
           ! global variable
           cmd%is_intrinsic = &
                global%var_list%is_intrinsic (cmd%name, follow_link = .true.)
           if (cmd%type == V_NONE) then
              cmd%type = &
                   global%var_list%get_type (cmd%name, follow_link = .true.)
           end if
        else if (associated (model_vars)) then  ! check model variable
           cmd%is_model_var = &
                model_vars%contains (cmd%name)
           if (cmd%type == V_NONE) then
              cmd%type = &
                   model_vars%get_type (cmd%name)
           end if
        end if
        if (cmd%type == V_NONE) then
           call msg_fatal ("Variable '" // char (cmd%name) // "' " &
                // "set without declaration")
           cmd%type = V_NONE;  return
        end if
        if (cmd%is_model_var) then
           if (new) then
              call msg_fatal ("Model variable '" // char (cmd%name) // "' " &
                   // "redeclared")
           else if (model_vars%is_locked (cmd%name)) then
              call msg_fatal ("Model variable '" // char (cmd%name) // "' " &
                   // "is locked")
           end if
        else
           select case (cmd%type)
           case (V_LOG)
              call global%var_list%append_log (cmd%name, &
                   intrinsic=cmd%is_intrinsic, user=.true.)
           case (V_INT)
              call global%var_list%append_int (cmd%name, &
                   intrinsic=cmd%is_intrinsic, user=.true.)
           case (V_REAL)
              call global%var_list%append_real (cmd%name, &
                   intrinsic=cmd%is_intrinsic, user=.true.)
           case (V_CMPLX)
              call global%var_list%append_cmplx (cmd%name, &
                   intrinsic=cmd%is_intrinsic, user=.true.)
           case (V_PDG)
              call global%var_list%append_pdg_array (cmd%name, &
                   intrinsic=cmd%is_intrinsic, user=.true.)
           case (V_STR)
              call global%var_list%append_string (cmd%name, &
                   intrinsic=cmd%is_intrinsic, user=.true.)
           end select
        end if
     end if
   end subroutine cmd_var_compile
 
 @ %def cmd_var_compile
 @ Execute.  Evaluate the definition and assign the variable value.
 If the variable is a model variable, take a snapshot of the model if necessary
 and set the variable in the local model.
 <<Commands: cmd var: TBP>>=
   procedure :: execute => cmd_var_execute
 <<Commands: procedures>>=
   subroutine cmd_var_execute (cmd, global)
     class(cmd_var_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     real(default) :: rval
     logical :: is_known, pacified
     var_list => global%get_var_list_ptr ()
     if (cmd%is_model_var) then
        pacified = var_list%get_lval (var_str ("?pacify"))
        rval = eval_real (cmd%pn_value, var_list, is_known=is_known)
        call global%model_set_real &
             (cmd%name, rval, verbose=.true., pacified=pacified)
     else if (cmd%type /= V_NONE) then
        call cmd%set_value (var_list, verbose=.true.)
     end if
   end subroutine cmd_var_execute
 
 @ %def cmd_var_execute
 @ Copy the value to the variable list, where the variable should already exist.
 <<Commands: cmd var: TBP>>=
   procedure :: set_value => cmd_var_set_value
 <<Commands: procedures>>=
   subroutine cmd_var_set_value (var, var_list, verbose, model_name)
     class(cmd_var_t), intent(inout) :: var
     type(var_list_t), intent(inout), target :: var_list
     logical, intent(in), optional :: verbose
     type(string_t), intent(in), optional :: model_name
     logical :: lval, pacified
     integer :: ival
     real(default) :: rval
     complex(default) :: cval
     type(pdg_array_t) :: aval
     type(string_t) :: sval
     logical :: is_known
     pacified = var_list%get_lval (var_str ("?pacify"))
     select case (var%type)
     case (V_LOG)
        lval = eval_log (var%pn_value, var_list, is_known=is_known)
        call var_list%set_log (var%name, &
             lval, is_known, verbose=verbose, model_name=model_name)
     case (V_INT)
        ival = eval_int (var%pn_value, var_list, is_known=is_known)
        call var_list%set_int (var%name, &
             ival, is_known, verbose=verbose, model_name=model_name)
     case (V_REAL)
        rval = eval_real (var%pn_value, var_list, is_known=is_known)
        call var_list%set_real (var%name, &
             rval, is_known, verbose=verbose, &
             model_name=model_name, pacified = pacified)
     case (V_CMPLX)
        cval = eval_cmplx (var%pn_value, var_list, is_known=is_known)
        call var_list%set_cmplx (var%name, &
             cval, is_known, verbose=verbose, &
             model_name=model_name, pacified = pacified)
     case (V_PDG)
        aval = eval_pdg_array (var%pn_value, var_list, is_known=is_known)
        call var_list%set_pdg_array (var%name, &
             aval, is_known, verbose=verbose, model_name=model_name)
     case (V_STR)
        sval = eval_string (var%pn_value, var_list, is_known=is_known)
        call var_list%set_string (var%name, &
             sval, is_known, verbose=verbose, model_name=model_name)
     end select
   end subroutine cmd_var_set_value
 
 @ %def cmd_var_set_value
 @
 \subsubsection{SLHA}
 Read a SLHA (SUSY Les Houches Accord) file to fill the appropriate
 model parameters.  We do not access the current variable record, but
 directly work on the appropriate SUSY model, which is loaded if
 necessary.
 
 We may be in read or write mode.  In the latter case, we may write
 just input parameters, or the complete spectrum, or the spectrum with
 all decays.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_slha_t
      private
      type(string_t) :: file
      logical :: write_mode = .false.
    contains
    <<Commands: cmd slha: TBP>>
   end type cmd_slha_t
 
 @ %def cmd_slha_t
 @ Output.
 <<Commands: cmd slha: TBP>>=
   procedure :: write => cmd_slha_write
 <<Commands: procedures>>=
   subroutine cmd_slha_write (cmd, unit, indent)
     class(cmd_slha_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,A)")  "slha: file name  = ", char (cmd%file)
     write (u, "(1x,A,L1)") "slha: write mode = ", cmd%write_mode
   end subroutine cmd_slha_write
 
 @ %def cmd_slha_write
 @ Compile.  Read the filename and store it.
 <<Commands: cmd slha: TBP>>=
   procedure :: compile => cmd_slha_compile
 <<Commands: procedures>>=
   subroutine cmd_slha_compile (cmd, global)
     class(cmd_slha_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_key, pn_arg, pn_file
     pn_key => parse_node_get_sub_ptr (cmd%pn)
     pn_arg => parse_node_get_next_ptr (pn_key)
     pn_file => parse_node_get_sub_ptr (pn_arg)
     call cmd%compile_options (global)
     cmd%pn_opt => parse_node_get_next_ptr (pn_arg)
     select case (char (parse_node_get_key (pn_key)))
     case ("read_slha")
        cmd%write_mode = .false.
     case ("write_slha")
        cmd%write_mode = .true.
     case default
        call parse_node_mismatch ("read_slha|write_slha",  cmd%pn)
     end select
     cmd%file = parse_node_get_string (pn_file)
   end subroutine cmd_slha_compile
 
 @ %def cmd_slha_compile
 @ Execute.  Read or write the specified SLHA file.  Behind the scenes,
 this will first read the WHIZARD model file, then read the SLHA file
 and assign the SLHA parameters as far as determined by
 [[dispatch_slha]].  Finally, the global variables are synchronized
 with the model.  This is similar to executing [[cmd_model]].
 <<Commands: cmd slha: TBP>>=
   procedure :: execute => cmd_slha_execute
 <<Commands: procedures>>=
   subroutine cmd_slha_execute (cmd, global)
     class(cmd_slha_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     logical :: input, spectrum, decays
     if (cmd%write_mode) then
        input = .true.
        spectrum = .false.
        decays = .false.
        if (.not. associated (cmd%local%model)) then
           call msg_fatal ("SLHA: local model not associated")
           return
        end if
        call slha_write_file &
             (cmd%file, cmd%local%model, &
              input = input, spectrum = spectrum, decays = decays)
     else
        if (.not. associated (global%model)) then
           call msg_fatal ("SLHA: global model not associated")
           return
        end if
        call dispatch_slha (cmd%local%var_list, &
             input = input, spectrum = spectrum, decays = decays)
        call global%ensure_model_copy ()
        call slha_read_file &
             (cmd%file, cmd%local%os_data, global%model, &
              input = input, spectrum = spectrum, decays = decays)
     end if
   end subroutine cmd_slha_execute
 
 @ %def cmd_slha_execute
 @
 \subsubsection{Show values}
 This command shows the current values of variables or other objects,
 in a suitably condensed form.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_show_t
      private
      type(string_t), dimension(:), allocatable :: name
    contains
    <<Commands: cmd show: TBP>>
   end type cmd_show_t
 
 @ %def cmd_show_t
 @ Output: list the object names, not values.
 <<Commands: cmd show: TBP>>=
   procedure :: write => cmd_show_write
 <<Commands: procedures>>=
   subroutine cmd_show_write (cmd, unit, indent)
     class(cmd_show_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, i
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)", advance="no")  "show: "
     if (allocated (cmd%name)) then
        do i = 1, size (cmd%name)
           write (u, "(1x,A)", advance="no")  char (cmd%name(i))
        end do
        write (u, *)
     else
        write (u, "(5x,A)")  "[undefined]"
     end if
   end subroutine cmd_show_write
 
 @ %def cmd_show_write
 @ Compile.  Allocate an array which is filled with the names of the
 variables to show.
 <<Commands: cmd show: TBP>>=
   procedure :: compile => cmd_show_compile
 <<Commands: procedures>>=
   subroutine cmd_show_compile (cmd, global)
     class(cmd_show_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg, pn_var, pn_prefix, pn_name
     type(string_t) :: key
     integer :: i, n_args
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 2)
     if (associated (pn_arg)) then
        select case (char (parse_node_get_rule_key (pn_arg)))
        case ("show_arg")
           cmd%pn_opt => parse_node_get_next_ptr (pn_arg)
        case default
           cmd%pn_opt => pn_arg
           pn_arg => null ()
        end select
     end if
     call cmd%compile_options (global)
     if (associated (pn_arg)) then
        n_args = parse_node_get_n_sub (pn_arg)
        allocate (cmd%name (n_args))
        pn_var => parse_node_get_sub_ptr (pn_arg)
        i = 0
        do while (associated (pn_var))
           i = i + 1
           select case (char (parse_node_get_rule_key (pn_var)))
           case ("model", "library", "beams", "iterations", &
                 "cuts", "weight", "int", "real", "complex", &
                 "scale", "factorization_scale", "renormalization_scale", &
                 "selection", "reweight", "analysis", "pdg", &
                 "stable", "unstable", "polarized", "unpolarized", &
                 "results", "expect", "intrinsic", "string", "logical")
              cmd%name(i) = parse_node_get_key (pn_var)
           case ("result_var")
              pn_prefix => parse_node_get_sub_ptr (pn_var)
              pn_name => parse_node_get_next_ptr (pn_prefix)
              if (associated (pn_name)) then
                 cmd%name(i) = parse_node_get_key (pn_prefix) &
                      // "(" // parse_node_get_string (pn_name) // ")"
              else
                 cmd%name(i) = parse_node_get_key (pn_prefix)
              end if
           case ("log_var", "string_var", "alias_var")
              pn_prefix => parse_node_get_sub_ptr (pn_var)
              pn_name => parse_node_get_next_ptr (pn_prefix)
              key = parse_node_get_key (pn_prefix)
              if (associated (pn_name)) then
                 select case (char (parse_node_get_rule_key (pn_name)))
                 case ("var_name")
                    select case (char (key))
                    case ("?", "$")  ! $ sign
                       cmd%name(i) = key // parse_node_get_string (pn_name)
                    case ("alias")
                       cmd%name(i) = parse_node_get_string (pn_name)
                    end select
                 case default
                    call parse_node_mismatch &
                         ("var_name",  pn_name)
                 end select
              else
                 cmd%name(i) = key
              end if
           case default
              cmd%name(i) = parse_node_get_string (pn_var)
           end select
           pn_var => parse_node_get_next_ptr (pn_var)
        end do
     else
        allocate (cmd%name (0))
     end if
   end subroutine cmd_show_compile
 
 @ %def cmd_show_compile
 @ Execute.  Scan the list of objects to show.
 <<Commands: parameters>>=
   integer, parameter, public :: SHOW_BUFFER_SIZE = 4096
 <<Commands: cmd show: TBP>>=
   procedure :: execute => cmd_show_execute
 <<Commands: procedures>>=
   subroutine cmd_show_execute (cmd, global)
     class(cmd_show_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list, model_vars
     type(model_t), pointer :: model
     type(string_t) :: name
     integer :: n, pdg
     type(flavor_t) :: flv
     type(process_library_t), pointer :: prc_lib
     type(process_t), pointer :: process
     logical :: pacified
     character(SHOW_BUFFER_SIZE) :: buffer
     type(string_t) :: out_file
     integer :: i, j, u, u_log, u_out, u_ext
     u = free_unit ()
     var_list => cmd%local%var_list
     if (associated (cmd%local%model)) then
        model_vars => cmd%local%model%get_var_list_ptr ()
     else
        model_vars => null ()
     end if
     pacified = var_list%get_lval (var_str ("?pacify"))
     out_file = var_list%get_sval (var_str ("$out_file"))
     if (file_list_is_open (global%out_files, out_file, action="write")) then
        call msg_message ("show: copying output to file '" &
             // char (out_file) // "'")
        u_ext = file_list_get_unit (global%out_files, out_file)
     else
        u_ext = -1
     end if
     open (u, status = "scratch", action = "readwrite")
     if (associated (cmd%local%model)) then
        name = cmd%local%model%get_name ()
     end if
     if (size (cmd%name) == 0) then
        if (associated (model_vars)) then
           call model_vars%write (model_name = name, &
                unit = u, pacified = pacified, follow_link = .false.)
        end if
        call var_list%write (unit = u, pacified = pacified)
     else
        do i = 1, size (cmd%name)
           select case (char (cmd%name(i)))
           case ("model")
              if (associated (cmd%local%model)) then
                 call cmd%local%model%show (u)
              else
                 write (u, "(A)")  "Model: [undefined]"
              end if
           case ("library")
              if (associated (cmd%local%prclib)) then
                 call cmd%local%prclib%show (u)
              else
                 write (u, "(A)")  "Process library: [undefined]"
              end if
           case ("beams")
              call cmd%local%show_beams (u)
           case ("iterations")
              call cmd%local%it_list%write (u)
           case ("results")
              call cmd%local%process_stack%show (u, fifo=.true.)
           case ("stable")
              call cmd%local%model%show_stable (u)
           case ("polarized")
              call cmd%local%model%show_polarized (u)
           case ("unpolarized")
              call cmd%local%model%show_unpolarized (u)
           case ("unstable")
              model => cmd%local%model
              call model%show_unstable (u)
              n = model%get_n_field ()
              do j = 1, n
                 pdg = model%get_pdg (j)
                 call flv%init (pdg, model)
                 if (.not. flv%is_stable ()) &
                      call show_unstable (cmd%local, pdg, u)
                 if (flv%has_antiparticle ()) then
                    associate (anti => flv%anti ())
                      if (.not. anti%is_stable ()) &
                           call show_unstable (cmd%local, -pdg, u)
                    end associate
                 end if
              end do
           case ("cuts", "weight", "scale", &
                "factorization_scale", "renormalization_scale", &
                "selection", "reweight", "analysis")
              call cmd%local%pn%show (cmd%name(i), u)
           case ("expect")
              call expect_summary (force = .true.)
           case ("intrinsic")
              call var_list%write (intrinsic=.true., unit=u, &
                   pacified = pacified)
           case ("logical")
              if (associated (model_vars)) then
                 call model_vars%write (only_type=V_LOG, &
                      model_name = name, unit=u, pacified = pacified, &
                      follow_link=.false.)
              end if
              call var_list%write (&
                   only_type=V_LOG, unit=u, pacified = pacified)
           case ("int")
              if (associated (model_vars)) then
                 call model_vars%write (only_type=V_INT, &
                      model_name = name, unit=u, pacified = pacified, &
                      follow_link=.false.)
              end if
              call var_list%write (only_type=V_INT, &
                   unit=u, pacified = pacified)
           case ("real")
              if (associated (model_vars)) then
                 call model_vars%write (only_type=V_REAL, &
                      model_name = name, unit=u, pacified = pacified, &
                      follow_link=.false.)
              end if
              call var_list%write (only_type=V_REAL, &
                   unit=u, pacified = pacified)
           case ("complex")
              if (associated (model_vars)) then
                 call model_vars%write (only_type=V_CMPLX, &
                      model_name = name, unit=u, pacified = pacified, &
                      follow_link=.false.)
              end if
              call var_list%write (only_type=V_CMPLX, &
                   unit=u, pacified = pacified)
           case ("pdg")
              if (associated (model_vars)) then
                 call model_vars%write (only_type=V_PDG, &
                      model_name = name, unit=u, pacified = pacified, &
                      follow_link=.false.)
              end if
              call var_list%write (only_type=V_PDG, &
                   unit=u, pacified = pacified)
           case ("string")
              if (associated (model_vars)) then
                 call model_vars%write (only_type=V_STR, &
                      model_name = name, unit=u, pacified = pacified, &
                      follow_link=.false.)
              end if
              call var_list%write (only_type=V_STR, &
                   unit=u, pacified = pacified)
           case default
              if (analysis_exists (cmd%name(i))) then
                 call analysis_write (cmd%name(i), u)
              else if (cmd%local%process_stack%exists (cmd%name(i))) then
                 process => cmd%local%process_stack%get_process_ptr (cmd%name(i))
                 call process%show (u)
              else if (associated (cmd%local%prclib_stack%get_library_ptr &
                   (cmd%name(i)))) then
                 prc_lib => cmd%local%prclib_stack%get_library_ptr (cmd%name(i))
                 call prc_lib%show (u)
              else if (associated (model_vars)) then
                 if (model_vars%contains (cmd%name(i), follow_link=.false.)) then
                    call model_vars%write_var (cmd%name(i), &
                         unit = u, model_name = name, pacified = pacified)
                 else if (var_list%contains (cmd%name(i))) then
                    call var_list%write_var (cmd%name(i), &
                         unit = u, pacified = pacified)
                 else
                    call msg_error ("show: object '" // char (cmd%name(i)) &
                         // "' not found")
                 end if
              else if (var_list%contains (cmd%name(i))) then
                 call var_list%write_var (cmd%name(i), &
                      unit = u, pacified = pacified)
              else
                 call msg_error ("show: object '" // char (cmd%name(i)) &
                      // "' not found")
              end if
           end select
        end do
     end if
     rewind (u)
     u_log = logfile_unit ()
     u_out = given_output_unit ()
     do
        read (u, "(A)", end = 1)  buffer
        if (u_log > 0)  write (u_log, "(A)")  trim (buffer)
        if (u_out > 0)  write (u_out, "(A)")  trim (buffer)
        if (u_ext > 0)  write (u_ext, "(A)")  trim (buffer)
     end do
 1   close (u)
     if (u_log > 0)  flush (u_log)
     if (u_out > 0)  flush (u_out)
     if (u_ext > 0)  flush (u_ext)
   end subroutine cmd_show_execute
 
 @ %def cmd_show_execute
 @
 \subsubsection{Clear values}
 This command clears the current values of variables or other objects,
 where this makes sense.  It parallels the [[show]] command.  The
 objects are cleared, but not deleted.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_clear_t
      private
      type(string_t), dimension(:), allocatable :: name
    contains
    <<Commands: cmd clear: TBP>>
   end type cmd_clear_t
 
 @ %def cmd_clear_t
 @ Output: list the names of the objects to be cleared.
 <<Commands: cmd clear: TBP>>=
   procedure :: write => cmd_clear_write
 <<Commands: procedures>>=
   subroutine cmd_clear_write (cmd, unit, indent)
     class(cmd_clear_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, i
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)", advance="no")  "clear: "
     if (allocated (cmd%name)) then
        do i = 1, size (cmd%name)
           write (u, "(1x,A)", advance="no")  char (cmd%name(i))
        end do
        write (u, *)
     else
        write (u, "(5x,A)")  "[undefined]"
     end if
   end subroutine cmd_clear_write
 
 @ %def cmd_clear_write
 @ Compile.  Allocate an array which is filled with the names of the
 objects to be cleared.
 
 Note: there is currently no need to account for options, but we
 prepare for that possibility.
 <<Commands: cmd clear: TBP>>=
   procedure :: compile => cmd_clear_compile
 <<Commands: procedures>>=
   subroutine cmd_clear_compile (cmd, global)
     class(cmd_clear_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg, pn_var, pn_prefix, pn_name
     type(string_t) :: key
     integer :: i, n_args
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 2)
     if (associated (pn_arg)) then
        select case (char (parse_node_get_rule_key (pn_arg)))
        case ("clear_arg")
           cmd%pn_opt => parse_node_get_next_ptr (pn_arg)
        case default
           cmd%pn_opt => pn_arg
           pn_arg => null ()
        end select
     end if
     call cmd%compile_options (global)
     if (associated (pn_arg)) then
        n_args = parse_node_get_n_sub (pn_arg)
        allocate (cmd%name (n_args))
        pn_var => parse_node_get_sub_ptr (pn_arg)
        i = 0
        do while (associated (pn_var))
           i = i + 1
           select case (char (parse_node_get_rule_key (pn_var)))
           case ("beams", "iterations", &
                 "cuts", "weight", &
                 "scale", "factorization_scale", "renormalization_scale", &
                 "selection", "reweight", "analysis", &
                 "unstable", "polarized", &
                 "expect")
              cmd%name(i) = parse_node_get_key (pn_var)
           case ("log_var", "string_var")
              pn_prefix => parse_node_get_sub_ptr (pn_var)
              pn_name => parse_node_get_next_ptr (pn_prefix)
              key = parse_node_get_key (pn_prefix)
              if (associated (pn_name)) then
                 select case (char (parse_node_get_rule_key (pn_name)))
                 case ("var_name")
                    select case (char (key))
                    case ("?", "$")  ! $ sign
                       cmd%name(i) = key // parse_node_get_string (pn_name)
                    end select
                 case default
                    call parse_node_mismatch &
                         ("var_name",  pn_name)
                 end select
              else
                 cmd%name(i) = key
              end if
           case default
              cmd%name(i) = parse_node_get_string (pn_var)
           end select
           pn_var => parse_node_get_next_ptr (pn_var)
        end do
     else
        allocate (cmd%name (0))
     end if
   end subroutine cmd_clear_compile
 
 @ %def cmd_clear_compile
 @ Execute.  Scan the list of objects to clear.
 
 Objects that can be shown but not cleared: model, library, results
 <<Commands: cmd clear: TBP>>=
   procedure :: execute => cmd_clear_execute
 <<Commands: procedures>>=
   subroutine cmd_clear_execute (cmd, global)
     class(cmd_clear_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     integer :: i
     logical :: success
     type(var_list_t), pointer :: model_vars
     if (size (cmd%name) == 0) then
        call msg_warning ("clear: no object specified")
     else
        do i = 1, size (cmd%name)
           success = .true.
           select case (char (cmd%name(i)))
           case ("beams")
              call cmd%local%clear_beams ()
           case ("iterations")
              call cmd%local%it_list%clear ()
           case ("polarized")
              call cmd%local%model%clear_polarized ()
           case ("unstable")
              call cmd%local%model%clear_unstable ()
           case ("cuts", "weight", "scale", &
                "factorization_scale", "renormalization_scale", &
                "selection", "reweight", "analysis")
              call cmd%local%pn%clear (cmd%name(i))
           case ("expect")
              call expect_clear ()
           case default
              if (analysis_exists (cmd%name(i))) then
                 call analysis_clear (cmd%name(i))
              else if (cmd%local%var_list%contains (cmd%name(i))) then
                 if (.not. cmd%local%var_list%is_locked (cmd%name(i))) then
                    call cmd%local%var_list%unset (cmd%name(i))
                 else
                    call msg_error ("clear: variable '" // char (cmd%name(i)) &
                         // "' is locked and can't be cleared")
                    success = .false.
                 end if
              else if (associated (cmd%local%model)) then
                 model_vars => cmd%local%model%get_var_list_ptr ()
                 if (model_vars%contains (cmd%name(i), follow_link=.false.)) then
                    call msg_error ("clear: variable '" // char (cmd%name(i)) &
                         // "' is a model variable and can't be cleared")
                 else
                    call msg_error ("clear: object '" // char (cmd%name(i)) &
                         // "' not found")
                 end if
                 success = .false.
              else
                 call msg_error ("clear: object '" // char (cmd%name(i)) &
                      // "' not found")
                 success = .false.
              end if
           end select
           if (success)  call msg_message ("cleared: " // char (cmd%name(i)))
        end do
     end if
   end subroutine cmd_clear_execute
 
 @ %def cmd_clear_execute
 @
 \subsubsection{Compare values of variables to expectation}
 The implementation is similar to the [[show]] command.  There are just
 two arguments: two values that should be compared.  For providing
 local values for the numerical tolerance, the command has a local
 argument list.
 
 If the expectation fails, an error condition is recorded.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_expect_t
      private
      type(parse_node_t), pointer :: pn_lexpr => null ()
    contains
    <<Commands: cmd expect: TBP>>
   end type cmd_expect_t
 
 @ %def cmd_expect_t
 @ Simply tell the status.
 <<Commands: cmd expect: TBP>>=
   procedure :: write => cmd_expect_write
 <<Commands: procedures>>=
   subroutine cmd_expect_write (cmd, unit, indent)
     class(cmd_expect_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     if (associated (cmd%pn_lexpr)) then
        write (u, "(1x,A)")  "expect: [expression associated]"
     else
        write (u, "(1x,A)")  "expect: [undefined]"
     end if
   end subroutine cmd_expect_write
 
 @ %def cmd_expect_write
 @ Compile.  This merely assigns the parse node, the actual compilation is done
 at execution.  This is necessary because the origin of variables
 (local/global) may change during execution.
 <<Commands: cmd expect: TBP>>=
   procedure :: compile => cmd_expect_compile
 <<Commands: procedures>>=
   subroutine cmd_expect_compile (cmd, global)
     class(cmd_expect_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 2)
     cmd%pn_opt => parse_node_get_next_ptr (pn_arg)
     cmd%pn_lexpr => parse_node_get_sub_ptr (pn_arg)
     call cmd%compile_options (global)
   end subroutine cmd_expect_compile
 
 @ %def cmd_expect_compile
 @ Execute.  Evaluate both arguments, print them and their difference
 (if numerical), and whether they agree.  Record the result.
 <<Commands: cmd expect: TBP>>=
   procedure :: execute => cmd_expect_execute
 <<Commands: procedures>>=
   subroutine cmd_expect_execute (cmd, global)
     class(cmd_expect_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     logical :: success, is_known
     var_list => cmd%local%get_var_list_ptr ()
     success = eval_log (cmd%pn_lexpr, var_list, is_known=is_known)
     if (is_known) then
        if (success) then
           call msg_message ("expect: success")
        else
           call msg_error ("expect: failure")
        end if
     else
        call msg_error ("expect: undefined result")
        success = .false.
     end if
     call expect_record (success)
   end subroutine cmd_expect_execute
 
 @ %def cmd_expect_execute
 @
 \subsubsection{Beams}
 The beam command includes both beam and structure-function
 definition.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_beams_t
      private
      integer :: n_in = 0
      type(parse_node_p), dimension(:), allocatable :: pn_pdg
      integer :: n_sf_record = 0
      integer, dimension(:), allocatable :: n_entry
      type(parse_node_p), dimension(:,:), allocatable :: pn_sf_entry
    contains
    <<Commands: cmd beams: TBP>>
   end type cmd_beams_t
 
 @ %def cmd_beams_t
 @ Output.  The particle expressions are not resolved.
 <<Commands: cmd beams: TBP>>=
   procedure :: write => cmd_beams_write
 <<Commands: procedures>>=
   subroutine cmd_beams_write (cmd, unit, indent)
     class(cmd_beams_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     select case (cmd%n_in)
     case (1)
        write (u, "(1x,A)")  "beams: 1 [decay]"
     case (2)
        write (u, "(1x,A)")  "beams: 2 [scattering]"
     case default
        write (u, "(1x,A)")  "beams: [undefined]"
     end select
     if (allocated (cmd%n_entry)) then
        if (cmd%n_sf_record > 0) then
           write (u, "(1x,A,99(1x,I0))")  "structure function entries:", &
                cmd%n_entry
        end if
     end if
   end subroutine cmd_beams_write
 
 @ %def cmd_beams_write
 @ Compile.  Find and assign the parse nodes.
 
 Note: local environments are not yet supported.
 <<Commands: cmd beams: TBP>>=
   procedure :: compile => cmd_beams_compile
 <<Commands: procedures>>=
   subroutine cmd_beams_compile (cmd, global)
     class(cmd_beams_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_beam_def, pn_beam_spec
     type(parse_node_t), pointer :: pn_beam_list
     type(parse_node_t), pointer :: pn_codes
     type(parse_node_t), pointer :: pn_strfun_seq, pn_strfun_pair
     type(parse_node_t), pointer :: pn_strfun_def
     integer :: i
     pn_beam_def => parse_node_get_sub_ptr (cmd%pn, 3)
     pn_beam_spec => parse_node_get_sub_ptr (pn_beam_def)
     pn_strfun_seq => parse_node_get_next_ptr (pn_beam_spec)
     pn_beam_list => parse_node_get_sub_ptr (pn_beam_spec)
     call cmd%compile_options (global)
     cmd%n_in = parse_node_get_n_sub (pn_beam_list)
     allocate (cmd%pn_pdg (cmd%n_in))
     pn_codes => parse_node_get_sub_ptr (pn_beam_list)
     do i = 1, cmd%n_in
        cmd%pn_pdg(i)%ptr => pn_codes
        pn_codes => parse_node_get_next_ptr (pn_codes)
     end do
     if (associated (pn_strfun_seq)) then
        cmd%n_sf_record = parse_node_get_n_sub (pn_beam_def) - 1
        allocate (cmd%n_entry (cmd%n_sf_record), source = 1)
        allocate (cmd%pn_sf_entry (2, cmd%n_sf_record))
        do i = 1, cmd%n_sf_record
           pn_strfun_pair => parse_node_get_sub_ptr (pn_strfun_seq, 2)
           pn_strfun_def => parse_node_get_sub_ptr (pn_strfun_pair)
           cmd%pn_sf_entry(1,i)%ptr => pn_strfun_def
           pn_strfun_def => parse_node_get_next_ptr (pn_strfun_def)
           cmd%pn_sf_entry(2,i)%ptr => pn_strfun_def
           if (associated (pn_strfun_def))  cmd%n_entry(i) = 2
           pn_strfun_seq => parse_node_get_next_ptr (pn_strfun_seq)
        end do
     else
        allocate (cmd%n_entry (0))
        allocate (cmd%pn_sf_entry (0, 0))
     end if
   end subroutine cmd_beams_compile
 
 @ %def cmd_beams_compile
 @ Command execution: Determine beam particles and structure-function
 names, if any.  The results are stored in the [[beam_structure]]
 component of the [[global]] data block.
 <<Commands: cmd beams: TBP>>=
   procedure :: execute => cmd_beams_execute
 <<Commands: procedures>>=
   subroutine cmd_beams_execute (cmd, global)
     class(cmd_beams_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(pdg_array_t) :: pdg_array
     integer, dimension(:), allocatable :: pdg
     type(flavor_t), dimension(:), allocatable :: flv
     type(parse_node_t), pointer :: pn_key
     type(string_t) :: sf_name
     integer :: i, j
     call lhapdf_global_reset ()
     var_list => cmd%local%get_var_list_ptr ()
     allocate (flv (cmd%n_in))
     do i = 1, cmd%n_in
        pdg_array = eval_pdg_array (cmd%pn_pdg(i)%ptr, var_list)
        pdg = pdg_array
        select case (size (pdg))
        case (1)
           call flv(i)%init ( pdg(1), cmd%local%model)
        case default
           call msg_fatal ("Beams: beam particles must be unique")
        end select
     end do
     select case (cmd%n_in)
     case (1)
        if (cmd%n_sf_record > 0) then
           call msg_fatal ("Beam setup: no structure functions allowed &
                &for decay")
        end if
        call global%beam_structure%init_sf (flv%get_name ())
     case (2)
        call global%beam_structure%init_sf (flv%get_name (), cmd%n_entry)
        do i = 1, cmd%n_sf_record
           do j = 1, cmd%n_entry(i)
              pn_key => parse_node_get_sub_ptr (cmd%pn_sf_entry(j,i)%ptr)
              sf_name = parse_node_get_key (pn_key)
              call global%beam_structure%set_sf (i, j, sf_name)
           end do
        end do
     end select
   end subroutine cmd_beams_execute
 
 @ %def cmd_beams_execute
 @
 \subsubsection{Density matrices for beam polarization}
 For holding beam polarization, we define a notation and a data
 structure for sparse matrices.  The entries (and the index
 expressions) are numerical expressions, so we use evaluation trees.
 
 Each entry in the sparse matrix is an n-tuple of expressions.  The first
 tuple elements represent index values, the last one is an arbitrary
 (complex) number.  Absent expressions are replaced by default-value rules.
 
 Note: Here, and in some other commands, we would like to store an evaluation
 tree, not just a parse node pointer.  However, the current expression handler
 wants all variables defined, so the evaluation tree can only be built by
 [[evaluate]], i.e., compiled just-in-time and evaluated immediately.
 <<Commands: types>>=
   type :: sentry_expr_t
      type(parse_node_p), dimension(:), allocatable :: expr
    contains
    <<Commands: sentry expr: TBP>>
   end type sentry_expr_t
 
 @ %def sentry_expr_t
 @ Compile parse nodes into evaluation trees.
 <<Commands: sentry expr: TBP>>=
   procedure :: compile => sentry_expr_compile
 <<Commands: procedures>>=
   subroutine sentry_expr_compile (sentry, pn)
     class(sentry_expr_t), intent(out) :: sentry
     type(parse_node_t), intent(in), target :: pn
     type(parse_node_t), pointer :: pn_expr, pn_extra
     integer :: n_expr, i
     n_expr = parse_node_get_n_sub (pn)
     allocate (sentry%expr (n_expr))
     if (n_expr > 0) then
        i = 0
        pn_expr => parse_node_get_sub_ptr (pn)
        pn_extra => parse_node_get_next_ptr (pn_expr)
        do i = 1, n_expr
           sentry%expr(i)%ptr => pn_expr
           if (associated (pn_extra)) then
              pn_expr => parse_node_get_sub_ptr (pn_extra, 2)
              pn_extra => parse_node_get_next_ptr (pn_extra)
           end if
        end do
     end if
   end subroutine sentry_expr_compile
 
 @ %def sentry_expr_compile
 @ Evaluate the expressions and return an index array of predefined
 length together with a complex value.  If the value (as the last expression)
 is undefined, set it to unity.  If index values are undefined, repeat
 the previous index value.
 <<Commands: sentry expr: TBP>>=
   procedure :: evaluate => sentry_expr_evaluate
 <<Commands: procedures>>=
   subroutine sentry_expr_evaluate (sentry, index, value, global)
     class(sentry_expr_t), intent(inout) :: sentry
     integer, dimension(:), intent(out) :: index
     complex(default), intent(out) :: value
     type(rt_data_t), intent(in), target :: global
     type(var_list_t), pointer :: var_list
     integer :: i, n_expr, n_index
     type(eval_tree_t) :: eval_tree
     var_list => global%get_var_list_ptr ()
     n_expr = size (sentry%expr)
     n_index = size (index)
     if (n_expr <= n_index + 1) then
        do i = 1, min (n_expr, n_index)
           associate (expr => sentry%expr(i))
             call eval_tree%init_expr (expr%ptr, var_list)
             call eval_tree%evaluate ()
             if (eval_tree%is_known ()) then
                index(i) = eval_tree%get_int ()
             else
                call msg_fatal ("Evaluating density matrix: undefined index")
             end if
           end associate
        end do
        do i = n_expr + 1, n_index
           index(i) = index(n_expr)
        end do
        if (n_expr == n_index + 1) then
           associate (expr => sentry%expr(n_expr))
             call eval_tree%init_expr (expr%ptr, var_list)
             call eval_tree%evaluate ()
             if (eval_tree%is_known ()) then
                value = eval_tree%get_cmplx ()
             else
                call msg_fatal ("Evaluating density matrix: undefined index")
             end if
             call eval_tree%final ()
           end associate
        else
           value = 1
        end if
     else
        call msg_fatal ("Evaluating density matrix: index expression too long")
     end if
   end subroutine sentry_expr_evaluate
 
 @ %def sentry_expr_evaluate
 @ The sparse matrix itself consists of an arbitrary number of entries.
 <<Commands: types>>=
   type :: smatrix_expr_t
      type(sentry_expr_t), dimension(:), allocatable :: entry
    contains
    <<Commands: smatrix expr: TBP>>
   end type smatrix_expr_t
 
 @ %def smatrix_expr_t
 @ Compile: assign sub-nodes to sentry-expressions and compile those.
 <<Commands: smatrix expr: TBP>>=
   procedure :: compile => smatrix_expr_compile
 <<Commands: procedures>>=
   subroutine smatrix_expr_compile (smatrix_expr, pn)
     class(smatrix_expr_t), intent(out) :: smatrix_expr
     type(parse_node_t), intent(in), target :: pn
     type(parse_node_t), pointer :: pn_arg, pn_entry
     integer :: n_entry, i
     pn_arg => parse_node_get_sub_ptr (pn, 2)
     if (associated (pn_arg)) then
        n_entry = parse_node_get_n_sub (pn_arg)
        allocate (smatrix_expr%entry (n_entry))
        pn_entry => parse_node_get_sub_ptr (pn_arg)
        do i = 1, n_entry
           call smatrix_expr%entry(i)%compile (pn_entry)
           pn_entry => parse_node_get_next_ptr (pn_entry)
        end do
     else
        allocate (smatrix_expr%entry (0))
     end if
   end subroutine smatrix_expr_compile
 
 @ %def smatrix_expr_compile
 @ Evaluate the entries and build a new [[smatrix]] object, which
 contains just the numerical results.
 <<Commands: smatrix expr: TBP>>=
   procedure :: evaluate => smatrix_expr_evaluate
 <<Commands: procedures>>=
   subroutine smatrix_expr_evaluate (smatrix_expr, smatrix, global)
     class(smatrix_expr_t), intent(inout) :: smatrix_expr
     type(smatrix_t), intent(out) :: smatrix
     type(rt_data_t), intent(in), target :: global
     integer, dimension(2) :: idx
     complex(default) :: value
     integer :: i, n_entry
     n_entry = size (smatrix_expr%entry)
     call smatrix%init (2, n_entry)
     do i = 1, n_entry
        call smatrix_expr%entry(i)%evaluate (idx, value, global)
        call smatrix%set_entry (i, idx, value)
     end do
   end subroutine smatrix_expr_evaluate
 
 @ %def smatrix_expr_evaluate
 @
 \subsubsection{Beam polarization density}
 
 The beam polarization command defines spin density matrix for one or
 two beams (scattering or decay).
 <<Commands: types>>=
   type, extends (command_t) :: cmd_beams_pol_density_t
      private
      integer :: n_in = 0
      type(smatrix_expr_t), dimension(:), allocatable :: smatrix
    contains
    <<Commands: cmd beams pol density: TBP>>
   end type cmd_beams_pol_density_t
 
 @ %def cmd_beams_pol_density_t
 @ Output.
 <<Commands: cmd beams pol density: TBP>>=
   procedure :: write => cmd_beams_pol_density_write
 <<Commands: procedures>>=
   subroutine cmd_beams_pol_density_write (cmd, unit, indent)
     class(cmd_beams_pol_density_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     select case (cmd%n_in)
     case (1)
        write (u, "(1x,A)")  "beams polarization setup: 1 [decay]"
     case (2)
        write (u, "(1x,A)")  "beams polarization setup: 2 [scattering]"
     case default
        write (u, "(1x,A)")  "beams polarization setup: [undefined]"
     end select
   end subroutine cmd_beams_pol_density_write
 
 @ %def cmd_beams_pol_density_write
 @ Compile.  Find and assign the parse nodes.
 
 Note: local environments are not yet supported.
 <<Commands: cmd beams pol density: TBP>>=
   procedure :: compile => cmd_beams_pol_density_compile
 <<Commands: procedures>>=
   subroutine cmd_beams_pol_density_compile (cmd, global)
     class(cmd_beams_pol_density_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_pol_spec, pn_smatrix
     integer :: i
     pn_pol_spec => parse_node_get_sub_ptr (cmd%pn, 3)
     call cmd%compile_options (global)
     cmd%n_in = parse_node_get_n_sub (pn_pol_spec)
     allocate (cmd%smatrix (cmd%n_in))
     pn_smatrix => parse_node_get_sub_ptr (pn_pol_spec)
     do i = 1, cmd%n_in
        call cmd%smatrix(i)%compile (pn_smatrix)
        pn_smatrix => parse_node_get_next_ptr (pn_smatrix)
     end do
   end subroutine cmd_beams_pol_density_compile
 
 @ %def cmd_beams_pol_density_compile
 @ Command execution: Fill polarization density matrices.  No check
 yet, the matrices are checked and normalized when the actual beam
 object is created, just before integration.  For intermediate storage,
 we use the [[beam_structure]] object in the [[global]] data set.
 <<Commands: cmd beams pol density: TBP>>=
   procedure :: execute => cmd_beams_pol_density_execute
 <<Commands: procedures>>=
   subroutine cmd_beams_pol_density_execute (cmd, global)
     class(cmd_beams_pol_density_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(smatrix_t) :: smatrix
     integer :: i
     call global%beam_structure%init_pol (cmd%n_in)
     do i = 1, cmd%n_in
        call cmd%smatrix(i)%evaluate (smatrix, global)
        call global%beam_structure%set_smatrix (i, smatrix)
     end do
   end subroutine cmd_beams_pol_density_execute
 
 @ %def cmd_beams_pol_density_execute
 @
 \subsubsection{Beam polarization fraction}
 In addition to the polarization density matrix, we can independently
 specify the polarization fraction for one or both beams.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_beams_pol_fraction_t
      private
      integer :: n_in = 0
      type(parse_node_p), dimension(:), allocatable :: expr
    contains
    <<Commands: cmd beams pol fraction: TBP>>
   end type cmd_beams_pol_fraction_t
 
 @ %def cmd_beams_pol_fraction_t
 @ Output.
 <<Commands: cmd beams pol fraction: TBP>>=
   procedure :: write => cmd_beams_pol_fraction_write
 <<Commands: procedures>>=
   subroutine cmd_beams_pol_fraction_write (cmd, unit, indent)
     class(cmd_beams_pol_fraction_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     select case (cmd%n_in)
     case (1)
        write (u, "(1x,A)")  "beams polarization fraction: 1 [decay]"
     case (2)
        write (u, "(1x,A)")  "beams polarization fraction: 2 [scattering]"
     case default
        write (u, "(1x,A)")  "beams polarization fraction: [undefined]"
     end select
   end subroutine cmd_beams_pol_fraction_write
 
 @ %def cmd_beams_pol_fraction_write
 @ Compile.  Find and assign the parse nodes.
 
 Note: local environments are not yet supported.
 <<Commands: cmd beams pol fraction: TBP>>=
   procedure :: compile => cmd_beams_pol_fraction_compile
 <<Commands: procedures>>=
   subroutine cmd_beams_pol_fraction_compile (cmd, global)
     class(cmd_beams_pol_fraction_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_frac_spec, pn_expr
     integer :: i
     pn_frac_spec => parse_node_get_sub_ptr (cmd%pn, 3)
     call cmd%compile_options (global)
     cmd%n_in = parse_node_get_n_sub (pn_frac_spec)
     allocate (cmd%expr (cmd%n_in))
     pn_expr => parse_node_get_sub_ptr (pn_frac_spec)
     do i = 1, cmd%n_in
        cmd%expr(i)%ptr => pn_expr
        pn_expr => parse_node_get_next_ptr (pn_expr)
     end do
   end subroutine cmd_beams_pol_fraction_compile
 
 @ %def cmd_beams_pol_fraction_compile
 @ Command execution: Retrieve the numerical values of the beam
 polarization fractions.  The results are stored in the
 [[beam_structure]] component of the [[global]] data block.
 <<Commands: cmd beams pol fraction: TBP>>=
   procedure :: execute => cmd_beams_pol_fraction_execute
 <<Commands: procedures>>=
   subroutine cmd_beams_pol_fraction_execute (cmd, global)
     class(cmd_beams_pol_fraction_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     real(default), dimension(:), allocatable :: pol_f
     type(eval_tree_t) :: expr
     integer :: i
     var_list => global%get_var_list_ptr ()
     allocate (pol_f (cmd%n_in))
     do i = 1, cmd%n_in
        call expr%init_expr (cmd%expr(i)%ptr, var_list)
        call expr%evaluate ()
        if (expr%is_known ()) then
           pol_f(i) = expr%get_real ()
        else
           call msg_fatal ("beams polarization fraction: undefined value")
        end if
        call expr%final ()
     end do
     call global%beam_structure%set_pol_f (pol_f)
   end subroutine cmd_beams_pol_fraction_execute
 
 @ %def cmd_beams_pol_fraction_execute
 @
 \subsubsection{Beam momentum}
 This is completely analogous to the previous command, hence we can use
 inheritance.
 <<Commands: types>>=
   type, extends (cmd_beams_pol_fraction_t) :: cmd_beams_momentum_t
    contains
    <<Commands: cmd beams momentum: TBP>>
   end type cmd_beams_momentum_t
 
 @ %def cmd_beams_momentum_t
 @ Output.
 <<Commands: cmd beams momentum: TBP>>=
   procedure :: write => cmd_beams_momentum_write
 <<Commands: procedures>>=
   subroutine cmd_beams_momentum_write (cmd, unit, indent)
     class(cmd_beams_momentum_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     select case (cmd%n_in)
     case (1)
        write (u, "(1x,A)")  "beams momentum: 1 [decay]"
     case (2)
        write (u, "(1x,A)")  "beams momentum: 2 [scattering]"
     case default
        write (u, "(1x,A)")  "beams momentum: [undefined]"
     end select
   end subroutine cmd_beams_momentum_write
 
 @ %def cmd_beams_momentum_write
 @ Compile: inherited.
 
 Command execution: Not inherited, but just the error string and the final
 command are changed.
 <<Commands: cmd beams momentum: TBP>>=
   procedure :: execute => cmd_beams_momentum_execute
 <<Commands: procedures>>=
   subroutine cmd_beams_momentum_execute (cmd, global)
     class(cmd_beams_momentum_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     real(default), dimension(:), allocatable :: p
     type(eval_tree_t) :: expr
     integer :: i
     var_list => global%get_var_list_ptr ()
     allocate (p (cmd%n_in))
     do i = 1, cmd%n_in
        call expr%init_expr (cmd%expr(i)%ptr, var_list)
        call expr%evaluate ()
        if (expr%is_known ()) then
           p(i) = expr%get_real ()
        else
           call msg_fatal ("beams momentum: undefined value")
        end if
        call expr%final ()
     end do
     call global%beam_structure%set_momentum (p)
   end subroutine cmd_beams_momentum_execute
 
 @ %def cmd_beams_momentum_execute
 @
 \subsubsection{Beam angles}
 Again, this is analogous.  There are two angles, polar angle $\theta$
 and azimuthal angle $\phi$, which can be set independently for both beams.
 <<Commands: types>>=
   type, extends (cmd_beams_pol_fraction_t) :: cmd_beams_theta_t
    contains
    <<Commands: cmd beams theta: TBP>>
   end type cmd_beams_theta_t
 
   type, extends (cmd_beams_pol_fraction_t) :: cmd_beams_phi_t
    contains
    <<Commands: cmd beams phi: TBP>>
   end type cmd_beams_phi_t
 
 @ %def cmd_beams_theta_t
 @ %def cmd_beams_phi_t
 @ Output.
 <<Commands: cmd beams theta: TBP>>=
   procedure :: write => cmd_beams_theta_write
 <<Commands: cmd beams phi: TBP>>=
   procedure :: write => cmd_beams_phi_write
 <<Commands: procedures>>=
   subroutine cmd_beams_theta_write (cmd, unit, indent)
     class(cmd_beams_theta_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     select case (cmd%n_in)
     case (1)
        write (u, "(1x,A)")  "beams theta: 1 [decay]"
     case (2)
        write (u, "(1x,A)")  "beams theta: 2 [scattering]"
     case default
        write (u, "(1x,A)")  "beams theta: [undefined]"
     end select
   end subroutine cmd_beams_theta_write
 
   subroutine cmd_beams_phi_write (cmd, unit, indent)
     class(cmd_beams_phi_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     select case (cmd%n_in)
     case (1)
        write (u, "(1x,A)")  "beams phi: 1 [decay]"
     case (2)
        write (u, "(1x,A)")  "beams phi: 2 [scattering]"
     case default
        write (u, "(1x,A)")  "beams phi: [undefined]"
     end select
   end subroutine cmd_beams_phi_write
 
 @ %def cmd_beams_theta_write
 @ %def cmd_beams_phi_write
 @ Compile: inherited.
 
 Command execution: Not inherited, but just the error string and the final
 command are changed.
 <<Commands: cmd beams theta: TBP>>=
   procedure :: execute => cmd_beams_theta_execute
 <<Commands: cmd beams phi: TBP>>=
   procedure :: execute => cmd_beams_phi_execute
 <<Commands: procedures>>=
   subroutine cmd_beams_theta_execute (cmd, global)
     class(cmd_beams_theta_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     real(default), dimension(:), allocatable :: theta
     type(eval_tree_t) :: expr
     integer :: i
     var_list => global%get_var_list_ptr ()
     allocate (theta (cmd%n_in))
     do i = 1, cmd%n_in
        call expr%init_expr (cmd%expr(i)%ptr, var_list)
        call expr%evaluate ()
        if (expr%is_known ()) then
           theta(i) = expr%get_real ()
        else
           call msg_fatal ("beams theta: undefined value")
        end if
        call expr%final ()
     end do
     call global%beam_structure%set_theta (theta)
   end subroutine cmd_beams_theta_execute
 
   subroutine cmd_beams_phi_execute (cmd, global)
     class(cmd_beams_phi_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     real(default), dimension(:), allocatable :: phi
     type(eval_tree_t) :: expr
     integer :: i
     var_list => global%get_var_list_ptr ()
     allocate (phi (cmd%n_in))
     do i = 1, cmd%n_in
        call expr%init_expr (cmd%expr(i)%ptr, var_list)
        call expr%evaluate ()
        if (expr%is_known ()) then
           phi(i) = expr%get_real ()
        else
           call msg_fatal ("beams phi: undefined value")
        end if
        call expr%final ()
     end do
     call global%beam_structure%set_phi (phi)
   end subroutine cmd_beams_phi_execute
 
 @ %def cmd_beams_theta_execute
 @ %def cmd_beams_phi_execute
 @
 \subsubsection{Cuts}
 Define a cut expression.  We store the parse tree for the right-hand
 side instead of compiling it.  Compilation is deferred to the process
 environment where the cut expression is used.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_cuts_t
      private
      type(parse_node_t), pointer :: pn_lexpr => null ()
    contains
    <<Commands: cmd cuts: TBP>>
   end type cmd_cuts_t
 
 @ %def cmd_cuts_t
 @ Output.  Do not print the parse tree, since this may get cluttered.
 Just a message that cuts have been defined.
 <<Commands: cmd cuts: TBP>>=
   procedure :: write => cmd_cuts_write
 <<Commands: procedures>>=
   subroutine cmd_cuts_write (cmd, unit, indent)
     class(cmd_cuts_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "cuts: [defined]"
   end subroutine cmd_cuts_write
 
 @ %def cmd_cuts_write
 @ Compile.  Simply store the parse (sub)tree.
 <<Commands: cmd cuts: TBP>>=
   procedure :: compile => cmd_cuts_compile
 <<Commands: procedures>>=
   subroutine cmd_cuts_compile (cmd, global)
     class(cmd_cuts_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     cmd%pn_lexpr => parse_node_get_sub_ptr (cmd%pn, 3)
   end subroutine cmd_cuts_compile
 
 @ %def cmd_cuts_compile
 @ Instead of evaluating the cut expression, link the parse tree to the
 global data set, such that it is compiled and executed in the
 appropriate process context.
 <<Commands: cmd cuts: TBP>>=
   procedure :: execute => cmd_cuts_execute
 <<Commands: procedures>>=
   subroutine cmd_cuts_execute (cmd, global)
     class(cmd_cuts_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     global%pn%cuts_lexpr => cmd%pn_lexpr
   end subroutine cmd_cuts_execute
 
 @ %def cmd_cuts_execute
 @
 \subsubsection{General, Factorization and Renormalization Scales}
 Define a scale expression for either the renormalization or the
 factorization scale.  We store the parse tree for the right-hand
 side instead of compiling it.  Compilation is deferred to the process
 environment where the expression is used.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_scale_t
      private
      type(parse_node_t), pointer :: pn_expr => null ()
    contains
    <<Commands: cmd scale: TBP>>
   end type cmd_scale_t
 
 @ %def cmd_scale_t
 <<Commands: types>>=
   type, extends (command_t) :: cmd_fac_scale_t
      private
      type(parse_node_t), pointer :: pn_expr => null ()
    contains
    <<Commands: cmd fac scale: TBP>>
   end type cmd_fac_scale_t
 
 @ %def cmd_fac_scale_t
 <<Commands: types>>=
   type, extends (command_t) :: cmd_ren_scale_t
      private
      type(parse_node_t), pointer :: pn_expr => null ()
    contains
    <<Commands: cmd ren scale: TBP>>
   end type cmd_ren_scale_t
 
 @ %def cmd_ren_scale_t
 @ Output. Do not print the parse tree, since this may get cluttered.
 Just a message that scale, renormalization and factorization have been
 defined, respectively.
 <<Commands: cmd scale: TBP>>=
   procedure :: write => cmd_scale_write
 <<Commands: procedures>>=
   subroutine cmd_scale_write (cmd, unit, indent)
     class(cmd_scale_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "scale: [defined]"
   end subroutine cmd_scale_write
 
 @ %def cmd_scale_write
 @
 <<Commands: cmd fac scale: TBP>>=
   procedure :: write => cmd_fac_scale_write
 <<Commands: procedures>>=
   subroutine cmd_fac_scale_write (cmd, unit, indent)
     class(cmd_fac_scale_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "factorization scale: [defined]"
   end subroutine cmd_fac_scale_write
 
 @ %def cmd_fac_scale_write
 @
 <<Commands: cmd ren scale: TBP>>=
   procedure :: write => cmd_ren_scale_write
 <<Commands: procedures>>=
   subroutine cmd_ren_scale_write (cmd, unit, indent)
     class(cmd_ren_scale_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "renormalization scale: [defined]"
   end subroutine cmd_ren_scale_write
 
 @ %def cmd_ren_scale_write
 @ Compile.  Simply store the parse (sub)tree.
 <<Commands: cmd scale: TBP>>=
   procedure :: compile => cmd_scale_compile
 <<Commands: procedures>>=
   subroutine cmd_scale_compile (cmd, global)
     class(cmd_scale_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     cmd%pn_expr => parse_node_get_sub_ptr (cmd%pn, 3)
   end subroutine cmd_scale_compile
 
 @ %def cmd_scale_compile
 @
 <<Commands: cmd fac scale: TBP>>=
   procedure :: compile => cmd_fac_scale_compile
 <<Commands: procedures>>=
   subroutine cmd_fac_scale_compile (cmd, global)
     class(cmd_fac_scale_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     cmd%pn_expr => parse_node_get_sub_ptr (cmd%pn, 3)
   end subroutine cmd_fac_scale_compile
 
 @ %def cmd_fac_scale_compile
 @
 <<Commands: cmd ren scale: TBP>>=
   procedure :: compile => cmd_ren_scale_compile
 <<Commands: procedures>>=
   subroutine cmd_ren_scale_compile (cmd, global)
     class(cmd_ren_scale_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     cmd%pn_expr => parse_node_get_sub_ptr (cmd%pn, 3)
   end subroutine cmd_ren_scale_compile
 
 @ %def cmd_ren_scale_compile
 @ Instead of evaluating the scale expression, link the parse tree to the
 global data set, such that it is compiled and executed in the
 appropriate process context.
 <<Commands: cmd scale: TBP>>=
   procedure :: execute => cmd_scale_execute
 <<Commands: procedures>>=
   subroutine cmd_scale_execute (cmd, global)
     class(cmd_scale_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     global%pn%scale_expr => cmd%pn_expr
   end subroutine cmd_scale_execute
 
 @ %def cmd_scale_execute
 @
 <<Commands: cmd fac scale: TBP>>=
   procedure :: execute => cmd_fac_scale_execute
 <<Commands: procedures>>=
   subroutine cmd_fac_scale_execute (cmd, global)
     class(cmd_fac_scale_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     global%pn%fac_scale_expr => cmd%pn_expr
   end subroutine cmd_fac_scale_execute
 
 @ %def cmd_fac_scale_execute
 @
 <<Commands: cmd ren scale: TBP>>=
   procedure :: execute => cmd_ren_scale_execute
 <<Commands: procedures>>=
   subroutine cmd_ren_scale_execute (cmd, global)
     class(cmd_ren_scale_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     global%pn%ren_scale_expr => cmd%pn_expr
   end subroutine cmd_ren_scale_execute
 
 @ %def cmd_ren_scale_execute
 @
 \subsubsection{Weight}
 Define a weight expression. The weight is applied to a process to be
 integrated, event by event. We store the parse tree for the right-hand
 side instead of compiling it. Compilation is deferred to the process
 environment where the expression is used.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_weight_t
      private
      type(parse_node_t), pointer :: pn_expr => null ()
    contains
    <<Commands: cmd weight: TBP>>
   end type cmd_weight_t
 
 @ %def cmd_weight_t
 @ Output. Do not print the parse tree, since this may get cluttered.
 Just a message that scale, renormalization and factorization have been
 defined, respectively.
 <<Commands: cmd weight: TBP>>=
   procedure :: write => cmd_weight_write
 <<Commands: procedures>>=
   subroutine cmd_weight_write (cmd, unit, indent)
     class(cmd_weight_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "weight expression: [defined]"
   end subroutine cmd_weight_write
 
 @ %def cmd_weight_write
 @ Compile.  Simply store the parse (sub)tree.
 <<Commands: cmd weight: TBP>>=
   procedure :: compile => cmd_weight_compile
 <<Commands: procedures>>=
   subroutine cmd_weight_compile (cmd, global)
     class(cmd_weight_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     cmd%pn_expr => parse_node_get_sub_ptr (cmd%pn, 3)
   end subroutine cmd_weight_compile
 
 @ %def cmd_weight_compile
 @ Instead of evaluating the expression, link the parse tree to the
 global data set, such that it is compiled and executed in the
 appropriate process context.
 <<Commands: cmd weight: TBP>>=
   procedure :: execute => cmd_weight_execute
 <<Commands: procedures>>=
   subroutine cmd_weight_execute (cmd, global)
     class(cmd_weight_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     global%pn%weight_expr => cmd%pn_expr
   end subroutine cmd_weight_execute
 
 @ %def cmd_weight_execute
 @
 \subsubsection{Selection}
 Define a selection expression.  This is to be applied upon simulation or
 event-file rescanning, event by event.  We store the parse tree for the
 right-hand side instead of compiling it.  Compilation is deferred to the
 environment where the expression is used.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_selection_t
      private
      type(parse_node_t), pointer :: pn_expr => null ()
    contains
    <<Commands: cmd selection: TBP>>
   end type cmd_selection_t
 
 @ %def cmd_selection_t
 @ Output. Do not print the parse tree, since this may get cluttered.
 Just a message that scale, renormalization and factorization have been
 defined, respectively.
 <<Commands: cmd selection: TBP>>=
   procedure :: write => cmd_selection_write
 <<Commands: procedures>>=
   subroutine cmd_selection_write (cmd, unit, indent)
     class(cmd_selection_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "selection expression: [defined]"
   end subroutine cmd_selection_write
 
 @ %def cmd_selection_write
 @ Compile.  Simply store the parse (sub)tree.
 <<Commands: cmd selection: TBP>>=
   procedure :: compile => cmd_selection_compile
 <<Commands: procedures>>=
   subroutine cmd_selection_compile (cmd, global)
     class(cmd_selection_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     cmd%pn_expr => parse_node_get_sub_ptr (cmd%pn, 3)
   end subroutine cmd_selection_compile
 
 @ %def cmd_selection_compile
 @ Instead of evaluating the expression, link the parse tree to the
 global data set, such that it is compiled and executed in the
 appropriate process context.
 <<Commands: cmd selection: TBP>>=
   procedure :: execute => cmd_selection_execute
 <<Commands: procedures>>=
   subroutine cmd_selection_execute (cmd, global)
     class(cmd_selection_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     global%pn%selection_lexpr => cmd%pn_expr
   end subroutine cmd_selection_execute
 
 @ %def cmd_selection_execute
 @
 \subsubsection{Reweight}
 Define a reweight expression.  This is to be applied upon simulation or
 event-file rescanning, event by event.  We store the parse tree for the
 right-hand side instead of compiling it.  Compilation is deferred to the
 environment where the expression is used.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_reweight_t
      private
      type(parse_node_t), pointer :: pn_expr => null ()
    contains
    <<Commands: cmd reweight: TBP>>
   end type cmd_reweight_t
 
 @ %def cmd_reweight_t
 @ Output. Do not print the parse tree, since this may get cluttered.
 Just a message that scale, renormalization and factorization have been
 defined, respectively.
 <<Commands: cmd reweight: TBP>>=
   procedure :: write => cmd_reweight_write
 <<Commands: procedures>>=
   subroutine cmd_reweight_write (cmd, unit, indent)
     class(cmd_reweight_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "reweight expression: [defined]"
   end subroutine cmd_reweight_write
 
 @ %def cmd_reweight_write
 @ Compile.  Simply store the parse (sub)tree.
 <<Commands: cmd reweight: TBP>>=
   procedure :: compile => cmd_reweight_compile
 <<Commands: procedures>>=
   subroutine cmd_reweight_compile (cmd, global)
     class(cmd_reweight_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     cmd%pn_expr => parse_node_get_sub_ptr (cmd%pn, 3)
   end subroutine cmd_reweight_compile
 
 @ %def cmd_reweight_compile
 @ Instead of evaluating the expression, link the parse tree to the
 global data set, such that it is compiled and executed in the
 appropriate process context.
 <<Commands: cmd reweight: TBP>>=
   procedure :: execute => cmd_reweight_execute
 <<Commands: procedures>>=
   subroutine cmd_reweight_execute (cmd, global)
     class(cmd_reweight_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     global%pn%reweight_expr => cmd%pn_expr
   end subroutine cmd_reweight_execute
 
 @ %def cmd_reweight_execute
 @
 \subsubsection{Alternative Simulation Setups}
 Together with simulation, we can re-evaluate event weights in the context of
 alternative setups.  The [[cmd_alt_setup_t]] object is designed to hold these
 setups, which are brace-enclosed command lists.  Compilation is deferred to
 the simulation environment where the setup expression is used.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_alt_setup_t
      private
      type(parse_node_p), dimension(:), allocatable :: setup
    contains
    <<Commands: cmd alt setup: TBP>>
   end type cmd_alt_setup_t
 
 @ %def cmd_alt_setup_t
 @ Output.  Print just a message that the alternative setup list has been
 defined.
 <<Commands: cmd alt setup: TBP>>=
   procedure :: write => cmd_alt_setup_write
 <<Commands: procedures>>=
   subroutine cmd_alt_setup_write (cmd, unit, indent)
     class(cmd_alt_setup_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,I0,A)")  "alt_setup: ", size (cmd%setup), " entries"
   end subroutine cmd_alt_setup_write
 
 @ %def cmd_alt_setup_write
 @ Compile.  Store the parse sub-trees in an array.
 <<Commands: cmd alt setup: TBP>>=
   procedure :: compile => cmd_alt_setup_compile
 <<Commands: procedures>>=
   subroutine cmd_alt_setup_compile (cmd, global)
     class(cmd_alt_setup_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_list, pn_setup
     integer :: i
     pn_list => parse_node_get_sub_ptr (cmd%pn, 3)
     if (associated (pn_list)) then
        allocate (cmd%setup (parse_node_get_n_sub (pn_list)))
        i = 1
        pn_setup => parse_node_get_sub_ptr (pn_list)
        do while (associated (pn_setup))
           cmd%setup(i)%ptr => pn_setup
           i = i + 1
           pn_setup => parse_node_get_next_ptr (pn_setup)
        end do
     else
        allocate (cmd%setup (0))
     end if
   end subroutine cmd_alt_setup_compile
 
 @ %def cmd_alt_setup_compile
 @ Execute.  Transfer the array of command lists to the global environment.
 <<Commands: cmd alt setup: TBP>>=
   procedure :: execute => cmd_alt_setup_execute
 <<Commands: procedures>>=
   subroutine cmd_alt_setup_execute (cmd, global)
     class(cmd_alt_setup_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     if (allocated (global%pn%alt_setup))  deallocate (global%pn%alt_setup)
     allocate (global%pn%alt_setup (size (cmd%setup)))
     global%pn%alt_setup = cmd%setup
   end subroutine cmd_alt_setup_execute
 
 @ %def cmd_alt_setup_execute
 @
 \subsubsection{Integration}
 Integrate several processes, consecutively with identical parameters.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_integrate_t
      private
      integer :: n_proc = 0
      type(string_t), dimension(:), allocatable :: process_id
    contains
    <<Commands: cmd integrate: TBP>>
   end type cmd_integrate_t
 
 @ %def cmd_integrate_t
 @ Output: we know the process IDs.
 <<Commands: cmd integrate: TBP>>=
   procedure :: write => cmd_integrate_write
 <<Commands: procedures>>=
   subroutine cmd_integrate_write (cmd, unit, indent)
     class(cmd_integrate_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, i
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)", advance="no")  "integrate ("
     do i = 1, cmd%n_proc
        if (i > 1)  write (u, "(A,1x)", advance="no")  ","
        write (u, "(A)", advance="no")  char (cmd%process_id(i))
     end do
     write (u, "(A)")  ")"
   end subroutine cmd_integrate_write
 
 @ %def cmd_integrate_write
 @ Compile.
 <<Commands: cmd integrate: TBP>>=
   procedure :: compile => cmd_integrate_compile
 <<Commands: procedures>>=
   subroutine cmd_integrate_compile (cmd, global)
     class(cmd_integrate_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_proclist, pn_proc
     integer :: i
     pn_proclist => parse_node_get_sub_ptr (cmd%pn, 2)
     cmd%pn_opt => parse_node_get_next_ptr (pn_proclist)
     call cmd%compile_options (global)
     cmd%n_proc = parse_node_get_n_sub (pn_proclist)
     allocate (cmd%process_id (cmd%n_proc))
     pn_proc => parse_node_get_sub_ptr (pn_proclist)
     do i = 1, cmd%n_proc
        cmd%process_id(i) = parse_node_get_string (pn_proc)
        call global%process_stack%init_result_vars (cmd%process_id(i))
        pn_proc => parse_node_get_next_ptr (pn_proc)
     end do
   end subroutine cmd_integrate_compile
 
 @ %def cmd_integrate_compile
 @ Command execution.  Integrate the process(es) with the predefined number
 of passes, iterations and calls.  For structure functions, cuts,
 weight and scale, use local definitions if present; by default, the local
 definitions are initialized with the global ones.
 
 The [[integrate]] procedure should take its input from the currently
 active local environment, but produce a process record in the stack of
 the global environment.
 
 Since the process acquires a snapshot of the variable list, so if the global
 list (or the local one) is deleted, this does no harm.  This implies that
 later changes of the variable list do not affect the stored process.
 <<Commands: cmd integrate: TBP>>=
   procedure :: execute => cmd_integrate_execute
 <<Commands: procedures>>=
   subroutine cmd_integrate_execute (cmd, global)
     class(cmd_integrate_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     integer :: i
     if (debug_on) call msg_debug (D_CORE, "cmd_integrate_execute")
     do i = 1, cmd%n_proc
        if (debug_on) call msg_debug (D_CORE, "cmd%process_id(i) ", cmd%process_id(i))
        call integrate_process (cmd%process_id(i), cmd%local, global)
        call global%process_stack%fill_result_vars (cmd%process_id(i))
        call global%process_stack%update_result_vars &
             (cmd%process_id(i), global%var_list)
        if (signal_is_pending ())  return
     end do
   end subroutine cmd_integrate_execute
 
 @ %def cmd_integrate_execute
 @
 \subsubsection{Observables}
 Declare an observable.  After the declaration, it can be used to
 record data, and at the end one can retrieve average and error.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_observable_t
      private
      type(string_t) :: id
    contains
    <<Commands: cmd observable: TBP>>
   end type cmd_observable_t
 
 @ %def cmd_observable_t
 @ Output.  We know the ID.
 <<Commands: cmd observable: TBP>>=
   procedure :: write => cmd_observable_write
 <<Commands: procedures>>=
   subroutine cmd_observable_write (cmd, unit, indent)
     class(cmd_observable_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,A)")  "observable: ", char (cmd%id)
   end subroutine cmd_observable_write
 
 @ %def cmd_observable_write
 @ Compile.  Just record the observable ID.
 <<Commands: cmd observable: TBP>>=
   procedure :: compile => cmd_observable_compile
 <<Commands: procedures>>=
   subroutine cmd_observable_compile (cmd, global)
     class(cmd_observable_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_tag
     pn_tag => parse_node_get_sub_ptr (cmd%pn, 2)
     if (associated (pn_tag)) then
        cmd%pn_opt => parse_node_get_next_ptr (pn_tag)
     end if
     call cmd%compile_options (global)
     select case (char (parse_node_get_rule_key (pn_tag)))
     case ("analysis_id")
        cmd%id = parse_node_get_string (pn_tag)
     case default
        call msg_bug ("observable: name expression not implemented (yet)")
     end select
   end subroutine cmd_observable_compile
 
 @ %def cmd_observable_compile
 @ Command execution.  This declares the observable and allocates it in
 the analysis store.
 <<Commands: cmd observable: TBP>>=
   procedure :: execute => cmd_observable_execute
 <<Commands: procedures>>=
   subroutine cmd_observable_execute (cmd, global)
     class(cmd_observable_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(graph_options_t) :: graph_options
     type(string_t) :: label, unit
     var_list => cmd%local%get_var_list_ptr ()
     label = var_list%get_sval (var_str ("$obs_label"))
     unit = var_list%get_sval (var_str ("$obs_unit"))
     call graph_options_init (graph_options)
     call set_graph_options (graph_options, var_list)
     call analysis_init_observable (cmd%id, label, unit, graph_options)
   end subroutine cmd_observable_execute
 
 @ %def cmd_observable_execute
 @
 \subsubsection{Histograms}
 Declare a histogram.  At minimum, we have to set lower and upper bound
 and bin width.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_histogram_t
      private
      type(string_t) :: id
      type(parse_node_t), pointer :: pn_lower_bound => null ()
      type(parse_node_t), pointer :: pn_upper_bound => null ()
      type(parse_node_t), pointer :: pn_bin_width => null ()
    contains
    <<Commands: cmd histogram: TBP>>
   end type cmd_histogram_t
 
 @ %def cmd_histogram_t
 @ Output.  Just print the ID.
 <<Commands: cmd histogram: TBP>>=
   procedure :: write => cmd_histogram_write
 <<Commands: procedures>>=
   subroutine cmd_histogram_write (cmd, unit, indent)
     class(cmd_histogram_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,A)")  "histogram: ", char (cmd%id)
   end subroutine cmd_histogram_write
 
 @ %def cmd_histogram_write
 @ Compile.  Record the histogram ID and initialize lower, upper bound
 and bin width.
 <<Commands: cmd histogram: TBP>>=
   procedure :: compile => cmd_histogram_compile
 <<Commands: procedures>>=
   subroutine cmd_histogram_compile (cmd, global)
     class(cmd_histogram_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_tag, pn_args, pn_arg1, pn_arg2, pn_arg3
     character(*), parameter :: e_illegal_use = &
        "illegal usage of 'histogram': insufficient number of arguments"
     pn_tag => parse_node_get_sub_ptr (cmd%pn, 2)
     pn_args => parse_node_get_next_ptr (pn_tag)
     if (associated (pn_args)) then
        pn_arg1 => parse_node_get_sub_ptr (pn_args)
        if (.not. associated (pn_arg1)) call msg_fatal (e_illegal_use)
        pn_arg2 => parse_node_get_next_ptr (pn_arg1)
        if (.not. associated (pn_arg2)) call msg_fatal (e_illegal_use)
        pn_arg3 => parse_node_get_next_ptr (pn_arg2)
        cmd%pn_opt => parse_node_get_next_ptr (pn_args)
     end if
     call cmd%compile_options (global)
     select case (char (parse_node_get_rule_key (pn_tag)))
     case ("analysis_id")
        cmd%id = parse_node_get_string (pn_tag)
     case default
        call msg_bug ("histogram: name expression not implemented (yet)")
     end select
     cmd%pn_lower_bound => pn_arg1
     cmd%pn_upper_bound => pn_arg2
     cmd%pn_bin_width => pn_arg3
   end subroutine cmd_histogram_compile
 
 @ %def cmd_histogram_compile
 @ Command execution.  This declares the histogram and allocates it in
 the analysis store.
 <<Commands: cmd histogram: TBP>>=
   procedure :: execute => cmd_histogram_execute
 <<Commands: procedures>>=
   subroutine cmd_histogram_execute (cmd, global)
     class(cmd_histogram_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     real(default) :: lower_bound, upper_bound, bin_width
     integer :: bin_number
     logical :: bin_width_is_used, normalize_bins
     type(string_t) :: obs_label, obs_unit
     type(graph_options_t) :: graph_options
     type(drawing_options_t) :: drawing_options
 
     var_list => cmd%local%get_var_list_ptr ()
     lower_bound = eval_real (cmd%pn_lower_bound, var_list)
     upper_bound = eval_real (cmd%pn_upper_bound, var_list)
     if (associated (cmd%pn_bin_width)) then
        bin_width = eval_real (cmd%pn_bin_width, var_list)
        bin_width_is_used = .true.
     else if (var_list%is_known (var_str ("n_bins"))) then
        bin_number = &
             var_list%get_ival (var_str ("n_bins"))
        bin_width_is_used = .false.
     else
        call msg_error ("Cmd '" // char (cmd%id) // &
             "': neither bin width nor number is defined")
     end if
     normalize_bins = &
          var_list%get_lval (var_str ("?normalize_bins"))
     obs_label = &
          var_list%get_sval (var_str ("$obs_label"))
     obs_unit = &
          var_list%get_sval (var_str ("$obs_unit"))
 
     call graph_options_init (graph_options)
     call set_graph_options (graph_options, var_list)
     call drawing_options_init_histogram (drawing_options)
     call set_drawing_options (drawing_options, var_list)
 
     if (bin_width_is_used) then
        call analysis_init_histogram &
             (cmd%id, lower_bound, upper_bound, bin_width, &
              normalize_bins, &
              obs_label, obs_unit, &
              graph_options, drawing_options)
     else
        call analysis_init_histogram &
             (cmd%id, lower_bound, upper_bound, bin_number, &
              normalize_bins, &
              obs_label, obs_unit, &
              graph_options, drawing_options)
     end if
   end subroutine cmd_histogram_execute
 
 @ %def cmd_histogram_execute
 @ Set the graph options from a variable list.
 <<Commands: procedures>>=
   subroutine set_graph_options (gro, var_list)
     type(graph_options_t), intent(inout) :: gro
     type(var_list_t), intent(in) :: var_list
     call graph_options_set (gro, title = &
          var_list%get_sval (var_str ("$title")))
     call graph_options_set (gro, description = &
          var_list%get_sval (var_str ("$description")))
     call graph_options_set (gro, x_label = &
          var_list%get_sval (var_str ("$x_label")))
     call graph_options_set (gro, y_label = &
          var_list%get_sval (var_str ("$y_label")))
     call graph_options_set (gro, width_mm = &
          var_list%get_ival (var_str ("graph_width_mm")))
     call graph_options_set (gro, height_mm = &
          var_list%get_ival (var_str ("graph_height_mm")))
     call graph_options_set (gro, x_log = &
          var_list%get_lval (var_str ("?x_log")))
     call graph_options_set (gro, y_log = &
          var_list%get_lval (var_str ("?y_log")))
     if (var_list%is_known (var_str ("x_min"))) &
          call graph_options_set (gro, x_min = &
          var_list%get_rval (var_str ("x_min")))
     if (var_list%is_known (var_str ("x_max"))) &
          call graph_options_set (gro, x_max = &
          var_list%get_rval (var_str ("x_max")))
     if (var_list%is_known (var_str ("y_min"))) &
          call graph_options_set (gro, y_min = &
          var_list%get_rval (var_str ("y_min")))
     if (var_list%is_known (var_str ("y_max"))) &
          call graph_options_set (gro, y_max = &
          var_list%get_rval (var_str ("y_max")))
     call graph_options_set (gro, gmlcode_bg = &
          var_list%get_sval (var_str ("$gmlcode_bg")))
     call graph_options_set (gro, gmlcode_fg = &
          var_list%get_sval (var_str ("$gmlcode_fg")))
   end subroutine set_graph_options
 
 @ %def set_graph_options
 @ Set the drawing options from a variable list.
 <<Commands: procedures>>=
   subroutine set_drawing_options (dro, var_list)
     type(drawing_options_t), intent(inout) :: dro
     type(var_list_t), intent(in) :: var_list
     if (var_list%is_known (var_str ("?draw_histogram"))) then
        if (var_list%get_lval (var_str ("?draw_histogram"))) then
           call drawing_options_set (dro, with_hbars = .true.)
        else
           call drawing_options_set (dro, with_hbars = .false., &
                with_base = .false., fill = .false., piecewise = .false.)
        end if
     end if
     if (var_list%is_known (var_str ("?draw_base"))) then
        if (var_list%get_lval (var_str ("?draw_base"))) then
           call drawing_options_set (dro, with_base = .true.)
        else
           call drawing_options_set (dro, with_base = .false., fill = .false.)
        end if
     end if
     if (var_list%is_known (var_str ("?draw_piecewise"))) then
        if (var_list%get_lval (var_str ("?draw_piecewise"))) then
           call drawing_options_set (dro, piecewise = .true.)
        else
           call drawing_options_set (dro, piecewise = .false.)
        end if
     end if
     if (var_list%is_known (var_str ("?fill_curve"))) then
        if (var_list%get_lval (var_str ("?fill_curve"))) then
           call drawing_options_set (dro, fill = .true., with_base = .true.)
        else
           call drawing_options_set (dro, fill = .false.)
        end if
     end if
     if (var_list%is_known (var_str ("?draw_curve"))) then
        if (var_list%get_lval (var_str ("?draw_curve"))) then
           call drawing_options_set (dro, draw = .true.)
        else
           call drawing_options_set (dro, draw = .false.)
        end if
     end if
     if (var_list%is_known (var_str ("?draw_errors"))) then
        if (var_list%get_lval (var_str ("?draw_errors"))) then
           call drawing_options_set (dro, err = .true.)
        else
           call drawing_options_set (dro, err = .false.)
        end if
     end if
     if (var_list%is_known (var_str ("?draw_symbols"))) then
        if (var_list%get_lval (var_str ("?draw_symbols"))) then
           call drawing_options_set (dro, symbols = .true.)
        else
           call drawing_options_set (dro, symbols = .false.)
        end if
     end if
     if (var_list%is_known (var_str ("$fill_options"))) then
        call drawing_options_set (dro, fill_options = &
             var_list%get_sval (var_str ("$fill_options")))
     end if
     if (var_list%is_known (var_str ("$draw_options"))) then
        call drawing_options_set (dro, draw_options = &
             var_list%get_sval (var_str ("$draw_options")))
     end if
     if (var_list%is_known (var_str ("$err_options"))) then
        call drawing_options_set (dro, err_options = &
             var_list%get_sval (var_str ("$err_options")))
     end if
     if (var_list%is_known (var_str ("$symbol"))) then
        call drawing_options_set (dro, symbol = &
             var_list%get_sval (var_str ("$symbol")))
     end if
     if (var_list%is_known (var_str ("$gmlcode_bg"))) then
        call drawing_options_set (dro, gmlcode_bg = &
             var_list%get_sval (var_str ("$gmlcode_bg")))
     end if
     if (var_list%is_known (var_str ("$gmlcode_fg"))) then
        call drawing_options_set (dro, gmlcode_fg = &
             var_list%get_sval (var_str ("$gmlcode_fg")))
     end if
   end subroutine set_drawing_options
 
 @ %def set_drawing_options
 @
 \subsubsection{Plots}
 Declare a plot.  No mandatory arguments, just options.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_plot_t
      private
      type(string_t) :: id
    contains
    <<Commands: cmd plot: TBP>>
   end type cmd_plot_t
 
 @ %def cmd_plot_t
 @ Output.  Just print the ID.
 <<Commands: cmd plot: TBP>>=
   procedure :: write => cmd_plot_write
 <<Commands: procedures>>=
   subroutine cmd_plot_write (cmd, unit, indent)
     class(cmd_plot_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,A)")  "plot: ", char (cmd%id)
   end subroutine cmd_plot_write
 
 @ %def cmd_plot_write
 @ Compile.  Record the plot ID and initialize lower, upper bound
 and bin width.
 <<Commands: cmd plot: TBP>>=
   procedure :: compile => cmd_plot_compile
 <<Commands: procedures>>=
   subroutine cmd_plot_compile (cmd, global)
     class(cmd_plot_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_tag
     pn_tag => parse_node_get_sub_ptr (cmd%pn, 2)
     cmd%pn_opt => parse_node_get_next_ptr (pn_tag)
     call cmd%init (pn_tag, global)
   end subroutine cmd_plot_compile
 
 @ %def cmd_plot_compile
 @ This init routine is separated because it is reused below for graph
 initialization.
 <<Commands: cmd plot: TBP>>=
   procedure :: init => cmd_plot_init
 <<Commands: procedures>>=
   subroutine cmd_plot_init (plot, pn_tag, global)
     class(cmd_plot_t), intent(inout) :: plot
     type(parse_node_t), intent(in), pointer :: pn_tag
     type(rt_data_t), intent(inout), target :: global
     call plot%compile_options (global)
     select case (char (parse_node_get_rule_key (pn_tag)))
     case ("analysis_id")
        plot%id = parse_node_get_string (pn_tag)
     case default
        call msg_bug ("plot: name expression not implemented (yet)")
     end select
   end subroutine cmd_plot_init
 
 @ %def cmd_plot_init
 @ Command execution.  This declares the plot and allocates it in
 the analysis store.
 <<Commands: cmd plot: TBP>>=
   procedure :: execute => cmd_plot_execute
 <<Commands: procedures>>=
   subroutine cmd_plot_execute (cmd, global)
     class(cmd_plot_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(graph_options_t) :: graph_options
     type(drawing_options_t) :: drawing_options
 
     var_list => cmd%local%get_var_list_ptr ()
     call graph_options_init (graph_options)
     call set_graph_options (graph_options, var_list)
     call drawing_options_init_plot (drawing_options)
     call set_drawing_options (drawing_options, var_list)
 
     call analysis_init_plot (cmd%id, graph_options, drawing_options)
   end subroutine cmd_plot_execute
 
 @ %def cmd_plot_execute
 @
 \subsubsection{Graphs}
 Declare a graph.  The graph is defined in terms of its contents.  Both the
 graph and its contents may carry options.
 
 The graph object contains its own ID as well as the IDs of its elements.  For
 the elements, we reuse the [[cmd_plot_t]] defined above.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_graph_t
      private
      type(string_t) :: id
      integer :: n_elements = 0
      type(cmd_plot_t), dimension(:), allocatable :: el
      type(string_t), dimension(:), allocatable :: element_id
    contains
    <<Commands: cmd graph: TBP>>
   end type cmd_graph_t
 
 @ %def cmd_graph_t
 @ Output.  Just print the ID.
 <<Commands: cmd graph: TBP>>=
   procedure :: write => cmd_graph_write
 <<Commands: procedures>>=
   subroutine cmd_graph_write (cmd, unit, indent)
     class(cmd_graph_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,A,A,I0,A)")  "graph: ", char (cmd%id), &
          " (", cmd%n_elements, " entries)"
   end subroutine cmd_graph_write
 
 @ %def cmd_graph_write
 @ Compile.  Record the graph ID and initialize lower, upper bound
 and bin width.  For compiling the graph element syntax, we use part of the
 [[cmd_plot_t]] compiler.
 
 Note: currently, we do not respect options, therefore just IDs on the RHS.
 <<Commands: cmd graph: TBP>>=
   procedure :: compile => cmd_graph_compile
 <<Commands: procedures>>=
   subroutine cmd_graph_compile (cmd, global)
     class(cmd_graph_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_term, pn_tag, pn_def, pn_app
     integer :: i
 
     pn_term => parse_node_get_sub_ptr (cmd%pn, 2)
     pn_tag => parse_node_get_sub_ptr (pn_term)
     cmd%pn_opt => parse_node_get_next_ptr (pn_tag)
     call cmd%compile_options (global)
     select case (char (parse_node_get_rule_key (pn_tag)))
     case ("analysis_id")
        cmd%id = parse_node_get_string (pn_tag)
     case default
        call msg_bug ("graph: name expression not implemented (yet)")
     end select
     pn_def => parse_node_get_next_ptr (pn_term, 2)
     cmd%n_elements = parse_node_get_n_sub (pn_def)
     allocate (cmd%element_id (cmd%n_elements))
     allocate (cmd%el (cmd%n_elements))
     pn_term => parse_node_get_sub_ptr (pn_def)
     pn_tag => parse_node_get_sub_ptr (pn_term)
     cmd%el(1)%pn_opt => parse_node_get_next_ptr (pn_tag)
     call cmd%el(1)%init (pn_tag, global)
     cmd%element_id(1) = parse_node_get_string (pn_tag)
     pn_app => parse_node_get_next_ptr (pn_term)
     do i = 2, cmd%n_elements
        pn_term => parse_node_get_sub_ptr (pn_app, 2)
        pn_tag => parse_node_get_sub_ptr (pn_term)
        cmd%el(i)%pn_opt => parse_node_get_next_ptr (pn_tag)
        call cmd%el(i)%init (pn_tag, global)
        cmd%element_id(i) = parse_node_get_string (pn_tag)
        pn_app => parse_node_get_next_ptr (pn_app)
     end do
 
   end subroutine cmd_graph_compile
 
 @ %def cmd_graph_compile
 @ Command execution.  This declares the graph, allocates it in
 the analysis store, and copies the graph elements.
 
 For the graph, we set graph and default drawing options.  For the elements, we
 reset individual drawing options.
 
 This accesses internals of the contained elements of type [[cmd_plot_t]], see
 above.  We might disentangle such an interdependency when this code is
 rewritten using proper type extension.
 <<Commands: cmd graph: TBP>>=
   procedure :: execute => cmd_graph_execute
 <<Commands: procedures>>=
   subroutine cmd_graph_execute (cmd, global)
     class(cmd_graph_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(graph_options_t) :: graph_options
     type(drawing_options_t) :: drawing_options
     integer :: i, type
 
     var_list => cmd%local%get_var_list_ptr ()
     call graph_options_init (graph_options)
     call set_graph_options (graph_options, var_list)
     call analysis_init_graph (cmd%id, cmd%n_elements, graph_options)
 
     do i = 1, cmd%n_elements
        if (associated (cmd%el(i)%options)) then
           call cmd%el(i)%options%execute (cmd%el(i)%local)
        end if
        type = analysis_store_get_object_type (cmd%element_id(i))
        select case (type)
        case (AN_HISTOGRAM)
           call drawing_options_init_histogram (drawing_options)
        case (AN_PLOT)
           call drawing_options_init_plot (drawing_options)
        end select
        call set_drawing_options (drawing_options, var_list)
        if (associated (cmd%el(i)%options)) then
           call set_drawing_options (drawing_options, cmd%el(i)%local%var_list)
        end if
        call analysis_fill_graph (cmd%id, i, cmd%element_id(i), drawing_options)
     end do
   end subroutine cmd_graph_execute
 
 @ %def cmd_graph_execute
 @
 \subsubsection{Analysis}
 Hold the analysis ID either as a string or as an expression:
 <<Commands: types>>=
   type :: analysis_id_t
     type(string_t) :: tag
     type(parse_node_t), pointer :: pn_sexpr => null ()
   end type analysis_id_t
 
 @ %def analysis_id_t
 @ Define the analysis expression.  We store the parse tree for the
 right-hand side instead of compiling it.  Compilation is deferred to
 the process environment where the analysis expression is used.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_analysis_t
      private
      type(parse_node_t), pointer :: pn_lexpr => null ()
    contains
    <<Commands: cmd analysis: TBP>>
   end type cmd_analysis_t
 
 @ %def cmd_analysis_t
 @ Output.  Print just a message that analysis has been defined.
 <<Commands: cmd analysis: TBP>>=
   procedure :: write => cmd_analysis_write
 <<Commands: procedures>>=
   subroutine cmd_analysis_write (cmd, unit, indent)
     class(cmd_analysis_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "analysis: [defined]"
   end subroutine cmd_analysis_write
 
 @ %def cmd_analysis_write
 @ Compile.  Simply store the parse (sub)tree.
 <<Commands: cmd analysis: TBP>>=
   procedure :: compile => cmd_analysis_compile
 <<Commands: procedures>>=
   subroutine cmd_analysis_compile (cmd, global)
     class(cmd_analysis_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     cmd%pn_lexpr => parse_node_get_sub_ptr (cmd%pn, 3)
   end subroutine cmd_analysis_compile
 
 @ %def cmd_analysis_compile
 @ Instead of evaluating the cut expression, link the parse tree to the
 global data set, such that it is compiled and executed in the
 appropriate process context.
 <<Commands: cmd analysis: TBP>>=
   procedure :: execute => cmd_analysis_execute
 <<Commands: procedures>>=
   subroutine cmd_analysis_execute (cmd, global)
     class(cmd_analysis_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     global%pn%analysis_lexpr => cmd%pn_lexpr
   end subroutine cmd_analysis_execute
 
 @ %def cmd_analysis_execute
 @
 \subsubsection{Write histograms and plots}
 The data type encapsulating the command:
 <<Commands: types>>=
   type, extends (command_t) :: cmd_write_analysis_t
      private
      type(analysis_id_t), dimension(:), allocatable :: id
      type(string_t), dimension(:), allocatable :: tag
    contains
    <<Commands: cmd write analysis: TBP>>
   end type cmd_write_analysis_t
 
 @ %def analysis_id_t
 @ %def cmd_write_analysis_t
 @ Output.  Just the keyword.
 <<Commands: cmd write analysis: TBP>>=
   procedure :: write => cmd_write_analysis_write
 <<Commands: procedures>>=
   subroutine cmd_write_analysis_write (cmd, unit, indent)
     class(cmd_write_analysis_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "write_analysis"
   end subroutine cmd_write_analysis_write
 
 @ %def cmd_write_analysis_write
 @ Compile.
 <<Commands: cmd write analysis: TBP>>=
   procedure :: compile => cmd_write_analysis_compile
 <<Commands: procedures>>=
   subroutine cmd_write_analysis_compile (cmd, global)
     class(cmd_write_analysis_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_clause, pn_args, pn_id
     integer :: n, i
     pn_clause => parse_node_get_sub_ptr (cmd%pn)
     pn_args => parse_node_get_sub_ptr (pn_clause, 2)
     cmd%pn_opt => parse_node_get_next_ptr (pn_clause)
     call cmd%compile_options (global)
     if (associated (pn_args)) then
        n = parse_node_get_n_sub (pn_args)
        allocate (cmd%id (n))
        do i = 1, n
            pn_id => parse_node_get_sub_ptr (pn_args, i)
            if (char (parse_node_get_rule_key (pn_id)) == "analysis_id") then
               cmd%id(i)%tag = parse_node_get_string (pn_id)
            else
               cmd%id(i)%pn_sexpr => pn_id
            end if
        end do
     else
        allocate (cmd%id (0))
     end if
   end subroutine cmd_write_analysis_compile
 
 @ %def cmd_write_analysis_compile
 @ The output format for real data values:
 <<Commands: parameters>>=
   character(*), parameter, public :: &
        DEFAULT_ANALYSIS_FILENAME = "whizard_analysis.dat"
   character(len=1), dimension(2), parameter, public :: &
        FORBIDDEN_ENDINGS1 = [ "o", "a" ]
   character(len=2), dimension(6), parameter, public :: &
        FORBIDDEN_ENDINGS2 = [ "mp", "ps", "vg", "pg", "lo", "la" ]
   character(len=3), dimension(18), parameter, public :: &
        FORBIDDEN_ENDINGS3 = [ "aux", "dvi", "evt", "evx", "f03", "f90", &
           "f95", "log", "ltp", "mpx", "olc", "olp", "pdf", "phs", "sin", &
           "tex", "vg2", "vgx" ]
 
 @ %def DEFAULT_ANALYSIS_FILENAME
 @ %def FORBIDDEN_ENDINGS1
 @ %def FORBIDDEN_ENDINGS2
 @ %def FORBIDDEN_ENDINGS3
 @ As this contains a lot of similar code to [[cmd_compile_analysis_execute]]
 we outsource the main code to a subroutine.
 <<Commands: cmd write analysis: TBP>>=
   procedure :: execute => cmd_write_analysis_execute
 <<Commands: procedures>>=
   subroutine cmd_write_analysis_execute (cmd, global)
     class(cmd_write_analysis_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     var_list => cmd%local%get_var_list_ptr ()
     call write_analysis_wrap (var_list, global%out_files, &
          cmd%id, tag = cmd%tag)
   end subroutine cmd_write_analysis_execute
 
 @ %def cmd_write_analysis_execute
 @ If the [[data_file]] optional argument is present, this is
 called from [[cmd_compile_analysis_execute]], which needs the file name for
 further processing, and requires the default format.  For the moment,
 parameters and macros for custom data processing are disabled.
 <<Commands: procedures>>=
   subroutine write_analysis_wrap (var_list, out_files, id, tag, data_file)
     type(var_list_t), intent(inout), target :: var_list
     type(file_list_t), intent(inout), target :: out_files
     type(analysis_id_t), dimension(:), intent(in), target :: id
     type(string_t), dimension(:), allocatable, intent(out) :: tag
     type(string_t), intent(out), optional :: data_file
     type(string_t) :: defaultfile, file
     integer :: i
     logical :: keep_open !, custom, header, columns
     type(string_t) :: extension !, comment_prefix, separator
 !!! JRR: WK please check (#542)
 !     integer :: type
 !     type(ifile_t) :: ifile
     logical :: one_file !, has_writer
 !     type(analysis_iterator_t) :: iterator
 !     type(rt_data_t), target :: sandbox
 !     type(command_list_t) :: writer
     defaultfile = var_list%get_sval (var_str ("$out_file"))
     if (present (data_file)) then
        if (defaultfile == "" .or. defaultfile == ".") then
           defaultfile = DEFAULT_ANALYSIS_FILENAME
        else
           if (scan (".", defaultfile) > 0) then
              call split (defaultfile, extension, ".", back=.true.)
              if (any (lower_case (char(extension)) == FORBIDDEN_ENDINGS1) .or. &
                  any (lower_case (char(extension)) == FORBIDDEN_ENDINGS2) .or. &
                  any (lower_case (char(extension)) == FORBIDDEN_ENDINGS3)) &
                  call msg_fatal ("The ending " // char(extension) // &
                  " is internal and not allowed as data file.")
              if (extension /= "") then
                 if (defaultfile /= "") then
                    defaultfile = defaultfile // "." // extension
                 else
                    defaultfile = "whizard_analysis." // extension
                 end if
              else
                 defaultfile = defaultfile // ".dat"
              endif
           else
              defaultfile = defaultfile // ".dat"
           end if
        end if
        data_file = defaultfile
     end if
     one_file = defaultfile /= ""
     if (one_file) then
        file = defaultfile
        keep_open = file_list_is_open (out_files, file, &
             action = "write")
        if (keep_open) then
           if (present (data_file)) then
              call msg_fatal ("Compiling analysis: File '" &
                   // char (data_file) &
                    // "' can't be used, it is already open.")
           else
              call msg_message ("Appending analysis data to file '" &
                   // char (file) // "'")
           end if
        else
           call file_list_open (out_files, file, &
                action = "write", status = "replace", position = "asis")
           call msg_message ("Writing analysis data to file '" &
                // char (file) // "'")
        end if
     end if
 
 !!! JRR: WK please check. Custom data output. Ticket #542
 !     if (present (data_file)) then
 !        custom = .false.
 !     else
 !        custom = var_list%get_lval (&
 !            var_str ("?out_custom"))
 !     end if
 !     comment_prefix = var_list%get_sval (&
 !          var_str ("$out_comment"))
 !     header = var_list%get_lval (&
 !          var_str ("?out_header"))
 !     write_yerr = var_list%get_lval (&
 !          var_str ("?out_yerr"))
 !     write_xerr = var_list%get_lval (&
 !          var_str ("?out_xerr"))
 
     call get_analysis_tags (tag, id, var_list)
     do i = 1, size (tag)
        call file_list_write_analysis &
             (out_files, file, tag(i))
     end do
     if (one_file .and. .not. keep_open) then
        call file_list_close (out_files, file)
     end if
 
   contains
 
     subroutine get_analysis_tags (analysis_tag, id, var_list)
       type(string_t), dimension(:), intent(out), allocatable :: analysis_tag
       type(analysis_id_t), dimension(:), intent(in) :: id
       type(var_list_t), intent(in), target :: var_list
       if (size (id) /= 0) then
          allocate (analysis_tag (size (id)))
          do i = 1, size (id)
             if (associated (id(i)%pn_sexpr)) then
                analysis_tag(i) = eval_string (id(i)%pn_sexpr, var_list)
             else
                analysis_tag(i) = id(i)%tag
             end if
          end do
       else
          call analysis_store_get_ids (tag)
       end if
     end subroutine get_analysis_tags
 
   end subroutine write_analysis_wrap
 
 @ %def write_analysis_wrap
 \subsubsection{Compile analysis results}
 This command writes files in a form suitable for GAMELAN and executes the
 appropriate commands to compile them.  The first part is identical to
 [[cmd_write_analysis]].
 <<Commands: types>>=
   type, extends (command_t) :: cmd_compile_analysis_t
      private
      type(analysis_id_t), dimension(:), allocatable :: id
      type(string_t), dimension(:), allocatable :: tag
    contains
    <<Commands: cmd compile analysis: TBP>>
   end type cmd_compile_analysis_t
 
 @ %def cmd_compile_analysis_t
 @ Output.  Just the keyword.
 <<Commands: cmd compile analysis: TBP>>=
   procedure :: write => cmd_compile_analysis_write
 <<Commands: procedures>>=
   subroutine cmd_compile_analysis_write (cmd, unit, indent)
     class(cmd_compile_analysis_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "compile_analysis"
   end subroutine cmd_compile_analysis_write
 
 @ %def cmd_compile_analysis_write
 @ Compile.
 <<Commands: cmd compile analysis: TBP>>=
   procedure :: compile => cmd_compile_analysis_compile
 <<Commands: procedures>>=
   subroutine cmd_compile_analysis_compile (cmd, global)
     class(cmd_compile_analysis_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_clause, pn_args, pn_id
     integer :: n, i
     pn_clause => parse_node_get_sub_ptr (cmd%pn)
     pn_args => parse_node_get_sub_ptr (pn_clause, 2)
     cmd%pn_opt => parse_node_get_next_ptr (pn_clause)
     call cmd%compile_options (global)
     if (associated (pn_args)) then
        n = parse_node_get_n_sub (pn_args)
        allocate (cmd%id (n))
        do i = 1, n
            pn_id => parse_node_get_sub_ptr (pn_args, i)
            if (char (parse_node_get_rule_key (pn_id)) == "analysis_id") then
               cmd%id(i)%tag = parse_node_get_string (pn_id)
            else
               cmd%id(i)%pn_sexpr => pn_id
            end if
        end do
     else
        allocate (cmd%id (0))
     end if
   end subroutine cmd_compile_analysis_compile
 
 @ %def cmd_compile_analysis_compile
 @ First write the analysis data to file, then write a GAMELAN driver and
 produce MetaPost and \TeX\ output.
 <<Commands: cmd compile analysis: TBP>>=
   procedure :: execute => cmd_compile_analysis_execute
 <<Commands: procedures>>=
   subroutine cmd_compile_analysis_execute (cmd, global)
     class(cmd_compile_analysis_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(string_t) :: file, basename, extension, driver_file, &
          makefile
     integer :: u_driver, u_makefile
     logical :: has_gmlcode, only_file
     var_list => cmd%local%get_var_list_ptr ()
     call write_analysis_wrap (var_list, &
          global%out_files, cmd%id, tag = cmd%tag, &
             data_file = file)
     basename = file
     if (scan (".", basename) > 0) then
       call split (basename, extension, ".", back=.true.)
     else
       extension = ""
     end if
     driver_file = basename // ".tex"
     makefile = basename // "_ana.makefile"
     u_driver = free_unit ()
     open (unit=u_driver, file=char(driver_file), &
           action="write", status="replace")
     if (allocated (cmd%tag)) then
        call analysis_write_driver (file, cmd%tag, unit=u_driver)
        has_gmlcode = analysis_has_plots (cmd%tag)
     else
        call analysis_write_driver (file, unit=u_driver)
        has_gmlcode = analysis_has_plots ()
     end if
     close (u_driver)
     u_makefile = free_unit ()
     open (unit=u_makefile, file=char(makefile), &
          action="write", status="replace")
     call analysis_write_makefile (basename, u_makefile, &
          has_gmlcode, global%os_data)
     close (u_makefile)
     call msg_message ("Compiling analysis results display in '" &
          // char (driver_file) // "'")
     call msg_message ("Providing analysis steering makefile '" &
          // char (makefile) // "'")
     only_file = global%var_list%get_lval &
          (var_str ("?analysis_file_only"))
     if (.not. only_file)  call analysis_compile_tex &
          (basename, has_gmlcode, global%os_data)
   end subroutine cmd_compile_analysis_execute
 
 @ %def cmd_compile_analysis_execute
 @
 \subsection{User-controlled output to data files}
 
 \subsubsection{Open file (output)}
 Open a file for output.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_open_out_t
      private
      type(parse_node_t), pointer :: file_expr => null ()
    contains
    <<Commands: cmd open out: TBP>>
   end type cmd_open_out_t
 
 @ %def cmd_open_out
 @ Finalizer for the embedded eval tree.
 <<Commands: procedures>>=
   subroutine cmd_open_out_final (object)
     class(cmd_open_out_t), intent(inout) :: object
   end subroutine cmd_open_out_final
 
 @ %def cmd_open_out_final
 @ Output (trivial here).
 <<Commands: cmd open out: TBP>>=
   procedure :: write => cmd_open_out_write
 <<Commands: procedures>>=
   subroutine cmd_open_out_write (cmd, unit, indent)
     class(cmd_open_out_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)", advance="no")  "open_out: <filename>"
   end subroutine cmd_open_out_write
 
 @ %def cmd_open_out_write
 @ Compile: create an eval tree for the filename expression.
 <<Commands: cmd open out: TBP>>=
   procedure :: compile => cmd_open_out_compile
 <<Commands: procedures>>=
   subroutine cmd_open_out_compile (cmd, global)
     class(cmd_open_out_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     cmd%file_expr => parse_node_get_sub_ptr (cmd%pn, 2)
     if (associated (cmd%file_expr)) then
        cmd%pn_opt => parse_node_get_next_ptr (cmd%file_expr)
     end if
     call cmd%compile_options (global)
   end subroutine cmd_open_out_compile
 
 @ %def cmd_open_out_compile
 @ Execute: append the file to the global list of open files.
 <<Commands: cmd open out: TBP>>=
   procedure :: execute => cmd_open_out_execute
 <<Commands: procedures>>=
   subroutine cmd_open_out_execute (cmd, global)
     class(cmd_open_out_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(eval_tree_t) :: file_expr
     type(string_t) :: file
     var_list => cmd%local%get_var_list_ptr ()
     call file_expr%init_sexpr (cmd%file_expr, var_list)
     call file_expr%evaluate ()
     if (file_expr%is_known ()) then
        file = file_expr%get_string ()
        call file_list_open (global%out_files, file, &
             action = "write", status = "replace", position = "asis")
     else
        call msg_fatal ("open_out: file name argument evaluates to unknown")
     end if
     call file_expr%final ()
   end subroutine cmd_open_out_execute
 
 @ %def cmd_open_out_execute
 
 \subsubsection{Open file (output)}
 Close an output file.  Except for the [[execute]] method, everything is
 analogous to the open command, so we can just inherit.
 <<Commands: types>>=
   type, extends (cmd_open_out_t) :: cmd_close_out_t
      private
    contains
    <<Commands: cmd close out: TBP>>
   end type cmd_close_out_t
 
 @ %def cmd_close_out
 @ Execute: remove the file from the global list of output files.
 <<Commands: cmd close out: TBP>>=
   procedure :: execute => cmd_close_out_execute
 <<Commands: procedures>>=
   subroutine cmd_close_out_execute (cmd, global)
     class(cmd_close_out_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(eval_tree_t) :: file_expr
     type(string_t) :: file
     var_list => cmd%local%var_list
     call file_expr%init_sexpr (cmd%file_expr, var_list)
     call file_expr%evaluate ()
     if (file_expr%is_known ()) then
        file = file_expr%get_string ()
        call file_list_close (global%out_files, file)
     else
        call msg_fatal ("close_out: file name argument evaluates to unknown")
     end if
     call file_expr%final ()
   end subroutine cmd_close_out_execute
 
 @ %def cmd_close_out_execute
 @
 \subsection{Print custom-formatted values}
 <<Commands: types>>=
   type, extends (command_t) :: cmd_printf_t
      private
      type(parse_node_t), pointer :: sexpr => null ()
      type(parse_node_t), pointer :: sprintf_fun => null ()
      type(parse_node_t), pointer :: sprintf_clause => null ()
      type(parse_node_t), pointer :: sprintf => null ()
    contains
    <<Commands: cmd printf: TBP>>
   end type cmd_printf_t
 
 @ %def cmd_printf_t
 @ Finalize.
 <<Commands: cmd printf: TBP>>=
   procedure :: final => cmd_printf_final
 <<Commands: procedures>>=
   subroutine cmd_printf_final (cmd)
     class(cmd_printf_t), intent(inout) :: cmd
     call parse_node_final (cmd%sexpr, recursive = .false.)
     deallocate (cmd%sexpr)
     call parse_node_final (cmd%sprintf_fun, recursive = .false.)
     deallocate (cmd%sprintf_fun)
     call parse_node_final (cmd%sprintf_clause, recursive = .false.)
     deallocate (cmd%sprintf_clause)
     call parse_node_final (cmd%sprintf, recursive = .false.)
     deallocate (cmd%sprintf)
   end subroutine cmd_printf_final
 
 @ %def cmd_printf_final
 @ Output.  Do not print the parse tree, since this may get cluttered.
 Just a message that cuts have been defined.
 <<Commands: cmd printf: TBP>>=
   procedure :: write => cmd_printf_write
 <<Commands: procedures>>=
   subroutine cmd_printf_write (cmd, unit, indent)
     class(cmd_printf_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "printf:"
   end subroutine cmd_printf_write
 
 @ %def cmd_printf_write
 @ Compile.  We create a fake parse node (subtree) with a [[sprintf]] command
 with identical arguments which can then be handled by the corresponding
 evaluation procedure.
 <<Commands: cmd printf: TBP>>=
   procedure :: compile => cmd_printf_compile
 <<Commands: procedures>>=
   subroutine cmd_printf_compile (cmd, global)
     class(cmd_printf_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_cmd, pn_clause, pn_args, pn_format
     pn_cmd => parse_node_get_sub_ptr (cmd%pn)
     pn_clause => parse_node_get_sub_ptr (pn_cmd)
     pn_format => parse_node_get_sub_ptr (pn_clause, 2)
     pn_args => parse_node_get_next_ptr (pn_clause)
     cmd%pn_opt => parse_node_get_next_ptr (pn_cmd)
     call cmd%compile_options (global)
     allocate (cmd%sexpr)
     call parse_node_create_branch (cmd%sexpr, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("sexpr")))
     allocate (cmd%sprintf_fun)
     call parse_node_create_branch (cmd%sprintf_fun, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("sprintf_fun")))
     allocate (cmd%sprintf_clause)
     call parse_node_create_branch (cmd%sprintf_clause, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("sprintf_clause")))
     allocate (cmd%sprintf)
     call parse_node_create_key (cmd%sprintf, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("sprintf")))
     call parse_node_append_sub (cmd%sprintf_clause, cmd%sprintf)
     call parse_node_append_sub (cmd%sprintf_clause, pn_format)
     call parse_node_freeze_branch (cmd%sprintf_clause)
     call parse_node_append_sub (cmd%sprintf_fun, cmd%sprintf_clause)
     if (associated (pn_args)) then
        call parse_node_append_sub (cmd%sprintf_fun, pn_args)
     end if
     call parse_node_freeze_branch (cmd%sprintf_fun)
     call parse_node_append_sub (cmd%sexpr, cmd%sprintf_fun)
     call parse_node_freeze_branch (cmd%sexpr)
   end subroutine cmd_printf_compile
 
 @ %def cmd_printf_compile
 @ Execute.  Evaluate the string (pretending this is a [[sprintf]] expression)
 and print it.
 <<Commands: cmd printf: TBP>>=
   procedure :: execute => cmd_printf_execute
 <<Commands: procedures>>=
   subroutine cmd_printf_execute (cmd, global)
     class(cmd_printf_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(string_t) :: string, file
     type(eval_tree_t) :: sprintf_expr
     logical :: advance
     var_list => cmd%local%get_var_list_ptr ()
     advance = var_list%get_lval (&
          var_str ("?out_advance"))
     file = var_list%get_sval (&
          var_str ("$out_file"))
     call sprintf_expr%init_sexpr (cmd%sexpr, var_list)
     call sprintf_expr%evaluate ()
     if (sprintf_expr%is_known ()) then
        string = sprintf_expr%get_string ()
        if (len (file) == 0) then
           call msg_result (char (string))
        else
           call file_list_write (global%out_files, file, string, advance)
        end if
     end if
   end subroutine cmd_printf_execute
 
 @ %def cmd_printf_execute
 @
 \subsubsection{Record data}
 The expression syntax already contains a [[record]] keyword; this evaluates to
 a logical which is always true, but it has the side-effect of recording data
 into analysis objects.  Here we define a command as an interface to this
 construct.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_record_t
      private
      type(parse_node_t), pointer :: pn_lexpr => null ()
    contains
    <<Commands: cmd record: TBP>>
   end type cmd_record_t
 
 @ %def cmd_record_t
 @ Output.  With the compile hack below, there is nothing of interest
 to print here.
 <<Commands: cmd record: TBP>>=
   procedure :: write => cmd_record_write
 <<Commands: procedures>>=
   subroutine cmd_record_write (cmd, unit, indent)
     class(cmd_record_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)")  "record"
   end subroutine cmd_record_write
 
 @ %def cmd_record_write
 @ Compile.  This is a hack which transforms the [[record]] command
 into a [[record]] expression, which we handle in the [[expressions]]
 module.
 <<Commands: cmd record: TBP>>=
   procedure :: compile => cmd_record_compile
 <<Commands: procedures>>=
   subroutine cmd_record_compile (cmd, global)
     class(cmd_record_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_lexpr, pn_lsinglet, pn_lterm, pn_record
     call parse_node_create_branch (pn_lexpr, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("lexpr")))
     call parse_node_create_branch (pn_lsinglet, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("lsinglet")))
     call parse_node_append_sub (pn_lexpr, pn_lsinglet)
     call parse_node_create_branch (pn_lterm, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("lterm")))
     call parse_node_append_sub (pn_lsinglet, pn_lterm)
     pn_record => parse_node_get_sub_ptr (cmd%pn)
     call parse_node_append_sub (pn_lterm, pn_record)
     cmd%pn_lexpr => pn_lexpr
   end subroutine cmd_record_compile
 
 @ %def cmd_record_compile
 @ Command execution.  Again, transfer this to the embedded expression
 and just forget the logical result.
 <<Commands: cmd record: TBP>>=
   procedure :: execute => cmd_record_execute
 <<Commands: procedures>>=
   subroutine cmd_record_execute (cmd, global)
     class(cmd_record_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     logical :: lval
     var_list => global%get_var_list_ptr ()
     lval = eval_log (cmd%pn_lexpr, var_list)
   end subroutine cmd_record_execute
 
 @ %def cmd_record_execute
 @
 \subsubsection{Unstable particles}
 Mark a particle as unstable.  For each unstable particle, we store a
 number of decay channels and compute their respective BRs.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_unstable_t
      private
      integer :: n_proc = 0
      type(string_t), dimension(:), allocatable :: process_id
      type(parse_node_t), pointer :: pn_prt_in => null ()
    contains
    <<Commands: cmd unstable: TBP>>
   end type cmd_unstable_t
 
 @ %def cmd_unstable_t
 @ Output: we know the process IDs.
 <<Commands: cmd unstable: TBP>>=
   procedure :: write => cmd_unstable_write
 <<Commands: procedures>>=
   subroutine cmd_unstable_write (cmd, unit, indent)
     class(cmd_unstable_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, i
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,1x,I0,1x,A)", advance="no")  &
          "unstable:", 1, "("
     do i = 1, cmd%n_proc
        if (i > 1)  write (u, "(A,1x)", advance="no")  ","
        write (u, "(A)", advance="no")  char (cmd%process_id(i))
     end do
     write (u, "(A)")  ")"
   end subroutine cmd_unstable_write
 
 @ %def cmd_unstable_write
 @ Compile.  Initiate an eval tree for the decaying particle and
 determine the decay channel process IDs.
 <<Commands: cmd unstable: TBP>>=
   procedure :: compile => cmd_unstable_compile
 <<Commands: procedures>>=
   subroutine cmd_unstable_compile (cmd, global)
     class(cmd_unstable_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_list, pn_proc
     integer :: i
     cmd%pn_prt_in => parse_node_get_sub_ptr (cmd%pn, 2)
     pn_list => parse_node_get_next_ptr (cmd%pn_prt_in)
     if (associated (pn_list)) then
        select case (char (parse_node_get_rule_key (pn_list)))
        case ("unstable_arg")
           cmd%n_proc = parse_node_get_n_sub (pn_list)
           cmd%pn_opt => parse_node_get_next_ptr (pn_list)
        case default
           cmd%n_proc = 0
           cmd%pn_opt => pn_list
           pn_list => null ()
        end select
     end if
     call cmd%compile_options (global)
     if (associated (pn_list)) then
        allocate (cmd%process_id (cmd%n_proc))
        pn_proc => parse_node_get_sub_ptr (pn_list)
        do i = 1, cmd%n_proc
           cmd%process_id(i) = parse_node_get_string (pn_proc)
           call cmd%local%process_stack%init_result_vars (cmd%process_id(i))
           pn_proc => parse_node_get_next_ptr (pn_proc)
        end do
     else
        allocate (cmd%process_id (0))
     end if
   end subroutine cmd_unstable_compile
 
 @ %def cmd_unstable_compile
 @ Command execution.  Evaluate the decaying particle and mark the decays in
 the current model object.
 <<Commands: cmd unstable: TBP>>=
   procedure :: execute => cmd_unstable_execute
 <<Commands: procedures>>=
   subroutine cmd_unstable_execute (cmd, global)
     class(cmd_unstable_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     logical :: auto_decays, auto_decays_radiative
     integer :: auto_decays_multiplicity
     logical :: isotropic_decay, diagonal_decay, polarized_decay
     integer :: decay_helicity
     type(pdg_array_t) :: pa_in
     integer :: pdg_in
     type(string_t) :: libname_cur, libname_dec
     type(string_t), dimension(:), allocatable :: auto_id, tmp_id
     integer :: n_proc_user
     integer :: i, u_tmp
     character(80) :: buffer
     var_list => cmd%local%get_var_list_ptr ()
     auto_decays = &
          var_list%get_lval (var_str ("?auto_decays"))
     if (auto_decays) then
        auto_decays_multiplicity = &
             var_list%get_ival (var_str ("auto_decays_multiplicity"))
        auto_decays_radiative = &
             var_list%get_lval (var_str ("?auto_decays_radiative"))
     end if
     isotropic_decay = &
          var_list%get_lval (var_str ("?isotropic_decay"))
     if (isotropic_decay) then
        diagonal_decay = .false.
        polarized_decay = .false.
     else
        diagonal_decay = &
             var_list%get_lval (var_str ("?diagonal_decay"))
        if (diagonal_decay) then
           polarized_decay = .false.
        else
           polarized_decay = &
                var_list%is_known (var_str ("decay_helicity"))
           if (polarized_decay) then
              decay_helicity = var_list%get_ival (var_str ("decay_helicity"))
           end if
        end if
     end if
     pa_in = eval_pdg_array (cmd%pn_prt_in, var_list)
     if (pdg_array_get_length (pa_in) /= 1) &
          call msg_fatal ("Unstable: decaying particle must be unique")
     pdg_in = pdg_array_get (pa_in, 1)
     n_proc_user = cmd%n_proc
     if (auto_decays) then
        call create_auto_decays (pdg_in, &
             auto_decays_multiplicity, auto_decays_radiative, &
             libname_dec, auto_id, cmd%local)
        allocate (tmp_id (cmd%n_proc + size (auto_id)))
        tmp_id(:cmd%n_proc) = cmd%process_id
        tmp_id(cmd%n_proc+1:) = auto_id
        call move_alloc (from = tmp_id, to = cmd%process_id)
        cmd%n_proc = size (cmd%process_id)
     end if
     libname_cur = cmd%local%prclib%get_name ()
     do i = 1, cmd%n_proc
        if (i == n_proc_user + 1) then
           call cmd%local%update_prclib &
                (cmd%local%prclib_stack%get_library_ptr (libname_dec))
        end if
        if (.not. global%process_stack%exists (cmd%process_id(i))) then
           call var_list%set_log &
                (var_str ("?decay_rest_frame"), .false., is_known = .true.)
           call integrate_process (cmd%process_id(i), cmd%local, global)
           call global%process_stack%fill_result_vars (cmd%process_id(i))
        end if
     end do
     call cmd%local%update_prclib &
          (cmd%local%prclib_stack%get_library_ptr (libname_cur))
     if (cmd%n_proc > 0) then
        if (polarized_decay) then
           call global%modify_particle (pdg_in, stable = .false., &
                decay = cmd%process_id, &
                isotropic_decay = .false., &
                diagonal_decay = .false., &
                decay_helicity = decay_helicity, &
                polarized = .false.)
        else
           call global%modify_particle (pdg_in, stable = .false., &
                decay = cmd%process_id, &
                isotropic_decay = isotropic_decay, &
                diagonal_decay = diagonal_decay, &
                polarized = .false.)
        end if
        u_tmp = free_unit ()
        open (u_tmp, status = "scratch", action = "readwrite")
        call show_unstable (global, pdg_in, u_tmp)
        rewind (u_tmp)
        do
           read (u_tmp, "(A)", end = 1)  buffer
           write (msg_buffer, "(A)")  trim (buffer)
           call msg_message ()
        end do
 1      continue
        close (u_tmp)
     else
        call err_unstable (global, pdg_in)
     end if
   end subroutine cmd_unstable_execute
 
 @ %def cmd_unstable_execute
 @ Show data for the current unstable particle.  This is called both by
 the [[unstable]] and by the [[show]] command.
 
 To determine decay branching rations, we look at the decay process IDs
 and inspect the corresponding [[integral()]] result variables.
 <<Commands: procedures>>=
   subroutine show_unstable (global, pdg, u)
     type(rt_data_t), intent(in), target :: global
     integer, intent(in) :: pdg, u
     type(flavor_t) :: flv
     type(string_t), dimension(:), allocatable :: decay
     real(default), dimension(:), allocatable :: br
     real(default) :: width
     type(process_t), pointer :: process
     type(process_component_def_t), pointer :: prc_def
     type(string_t), dimension(:), allocatable :: prt_out, prt_out_str
     integer :: i, j
     logical :: opened
     call flv%init (pdg, global%model)
     call flv%get_decays (decay)
     if (.not. allocated (decay))  return
     allocate (prt_out_str (size (decay)))
     allocate (br (size (decay)))
     do i = 1, size (br)
        process => global%process_stack%get_process_ptr (decay(i))
        prc_def => process%get_component_def_ptr (1)
        call prc_def%get_prt_out (prt_out)
        prt_out_str(i) = prt_out(1)
        do j = 2, size (prt_out)
           prt_out_str(i) = prt_out_str(i) // ", " // prt_out(j)
        end do
        br(i) = global%get_rval ("integral(" // decay(i) // ")")
     end do
     if (all (br >= 0)) then
        if (any (br > 0)) then
           width = sum (br)
           br = br / sum (br)
           write (u, "(A)") "Unstable particle " &
                // char (flv%get_name ()) &
                // ": computed branching ratios:"
           do i = 1, size (br)
              write (u, "(2x,A,':'," // FMT_14 // ",3x,A)") &
                   char (decay(i)), br(i), char (prt_out_str(i))
           end do
           write (u, "(2x,'Total width ='," // FMT_14 // ",' GeV (computed)')")  width
           write (u, "(2x,'            ='," // FMT_14 // ",' GeV (preset)')") &
                flv%get_width ()
           if (flv%decays_isotropically ()) then
              write (u, "(2x,A)")  "Decay options: isotropic"
           else if (flv%decays_diagonal ()) then
              write (u, "(2x,A)")  "Decay options: &
                   &projection on diagonal helicity states"
           else if (flv%has_decay_helicity ()) then
              write (u, "(2x,A,1x,I0)")  "Decay options: projection onto helicity =", &
                   flv%get_decay_helicity ()
           else
              write (u, "(2x,A)")  "Decay options: helicity treated exactly"
           end if
        else
           inquire (unit = u, opened = opened)
           if (opened .and. .not. mask_fatal_errors)  close (u)
           call msg_fatal ("Unstable particle " &
                // char (flv%get_name ()) &
                // ": partial width vanishes for all decay channels")
        end if
     else
        inquire (unit = u, opened = opened)
        if (opened .and. .not. mask_fatal_errors)  close (u)
        call msg_fatal ("Unstable particle " &
                // char (flv%get_name ()) &
                // ": partial width is negative")
     end if
   end subroutine show_unstable
 
 @ %def show_unstable
 @ If no decays have been found, issue a non-fatal error.
 <<Commands: procedures>>=
   subroutine err_unstable (global, pdg)
     type(rt_data_t), intent(in), target :: global
     integer, intent(in) :: pdg
     type(flavor_t) :: flv
     call flv%init (pdg, global%model)
     call msg_error ("Unstable: no allowed decays found for particle " &
          // char (flv%get_name ()) // ", keeping as stable")
   end subroutine err_unstable
 
 @ %def err_unstable
 @ Auto decays: create process IDs and make up process
 configurations, using the PDG codes generated by the [[ds_table]] make
 method.
 
 We allocate and use a self-contained process library that contains only the
 decay processes of the current particle.  When done, we revert the global
 library pointer to the original library but return the name of the new one.
 The new library becomes part of the global library stack and can thus be
 referred to at any time.
 <<Commands: procedures>>=
   subroutine create_auto_decays &
        (pdg_in, mult, rad, libname_dec, process_id, global)
     integer, intent(in) :: pdg_in
     integer, intent(in) :: mult
     logical, intent(in) :: rad
     type(string_t), intent(out) :: libname_dec
     type(string_t), dimension(:), allocatable, intent(out) :: process_id
     type(rt_data_t), intent(inout) :: global
     type(prclib_entry_t), pointer :: lib_entry
     type(process_library_t), pointer :: lib
     type(ds_table_t) :: ds_table
     type(split_constraints_t) :: constraints
     type(pdg_array_t), dimension(:), allocatable :: pa_out
     character(80) :: buffer
     character :: p_or_a
     type(string_t) :: process_string, libname_cur
     type(flavor_t) :: flv_in, flv_out
     type(string_t) :: prt_in
     type(string_t), dimension(:), allocatable :: prt_out
     type(process_configuration_t) :: prc_config
     integer :: i, j, k
     call flv_in%init (pdg_in, global%model)
     if (rad) then
        call constraints%init (2)
     else
        call constraints%init (3)
        call constraints%set (3, constrain_radiation ())
     end if
     call constraints%set (1, constrain_n_tot (mult))
     call constraints%set (2, &
          constrain_mass_sum (flv_in%get_mass (), margin = 0._default))
     call ds_table%make (global%model, pdg_in, constraints)
     prt_in = flv_in%get_name ()
     if (pdg_in > 0) then
        p_or_a = "p"
     else
        p_or_a = "a"
     end if
     if (ds_table%get_length () == 0) then
        call msg_warning ("Auto-decays: Particle " // char (prt_in) // ": " &
             // "no decays found")
        libname_dec = ""
        allocate (process_id (0))
     else
        call msg_message ("Creating decay process library for particle " &
             // char (prt_in))
        libname_cur = global%prclib%get_name ()
        write (buffer, "(A,A,I0)")  "_d", p_or_a, abs (pdg_in)
        libname_dec = libname_cur // trim (buffer)
        lib => global%prclib_stack%get_library_ptr (libname_dec)
        if (.not. (associated (lib))) then
           allocate (lib_entry)
           call lib_entry%init (libname_dec)
           lib => lib_entry%process_library_t
           call global%add_prclib (lib_entry)
        else
           call global%update_prclib (lib)
        end if
        allocate (process_id (ds_table%get_length ()))
        do i = 1, size (process_id)
           write (buffer, "(A,'_',A,I0,'_',I0)") &
                "decay", p_or_a, abs (pdg_in), i
           process_id(i) = trim (buffer)
           process_string = process_id(i) // ": " // prt_in // " =>"
           call ds_table%get_pdg_out (i, pa_out)
           allocate (prt_out (size (pa_out)))
           do j = 1, size (pa_out)
              do k = 1, pa_out(j)%get_length ()
                 call flv_out%init (pa_out(j)%get (k), global%model)
                 if (k == 1) then
                    prt_out(j) = flv_out%get_name ()
                 else
                    prt_out(j) = prt_out(j) // ":" // flv_out%get_name ()
                 end if
              end do
              process_string = process_string // " " // prt_out(j)
           end do
           call msg_message (char (process_string))
           call prc_config%init (process_id(i), 1, 1, &
                global%model, global%var_list, &
                nlo_process = global%nlo_fixed_order)
           !!! Causes runtime error with gfortran 4.9.1
           ! call prc_config%setup_component (1, &
           !      new_prt_spec ([prt_in]), new_prt_spec (prt_out), global%model, global%var_list)
           !!! Workaround:
           call prc_config%setup_component (1, &
                [new_prt_spec (prt_in)], new_prt_spec (prt_out), global%model, global%var_list)
           call prc_config%record (global)
           deallocate (prt_out)
           deallocate (pa_out)
        end do
        lib => global%prclib_stack%get_library_ptr (libname_cur)
        call global%update_prclib (lib)
     end if
     call ds_table%final ()
   end subroutine create_auto_decays
 
 @ %def create_auto_decays
 @
 \subsubsection{(Stable particles}
 Revert the unstable declaration for a list of particles.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_stable_t
      private
      type(parse_node_p), dimension(:), allocatable :: pn_pdg
    contains
    <<Commands: cmd stable: TBP>>
   end type cmd_stable_t
 
 @ %def cmd_stable_t
 @ Output: we know only the number of particles.
 <<Commands: cmd stable: TBP>>=
   procedure :: write => cmd_stable_write
 <<Commands: procedures>>=
   subroutine cmd_stable_write (cmd, unit, indent)
     class(cmd_stable_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,1x,I0)")  "stable:", size (cmd%pn_pdg)
   end subroutine cmd_stable_write
 
 @ %def cmd_stable_write
 @ Compile.  Assign parse nodes for the particle IDs.
 <<Commands: cmd stable: TBP>>=
   procedure :: compile => cmd_stable_compile
 <<Commands: procedures>>=
   subroutine cmd_stable_compile (cmd, global)
     class(cmd_stable_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_list, pn_prt
     integer :: n, i
     pn_list => parse_node_get_sub_ptr (cmd%pn, 2)
     cmd%pn_opt => parse_node_get_next_ptr (pn_list)
     call cmd%compile_options (global)
     n = parse_node_get_n_sub (pn_list)
     allocate (cmd%pn_pdg (n))
     pn_prt => parse_node_get_sub_ptr (pn_list)
     i = 1
     do while (associated (pn_prt))
        cmd%pn_pdg(i)%ptr => pn_prt
        pn_prt  => parse_node_get_next_ptr (pn_prt)
        i = i + 1
     end do
   end subroutine cmd_stable_compile
 
 @ %def cmd_stable_compile
 @ Execute: apply the modifications to the current model.
 <<Commands: cmd stable: TBP>>=
   procedure :: execute => cmd_stable_execute
 <<Commands: procedures>>=
   subroutine cmd_stable_execute (cmd, global)
     class(cmd_stable_t), intent(inout) :: cmd
     type(rt_data_t), target, intent(inout) :: global
     type(var_list_t), pointer :: var_list
     type(pdg_array_t) :: pa
     integer :: pdg
     type(flavor_t) :: flv
     integer :: i
     var_list => cmd%local%get_var_list_ptr ()
     do i = 1, size (cmd%pn_pdg)
        pa = eval_pdg_array (cmd%pn_pdg(i)%ptr, var_list)
        if (pdg_array_get_length (pa) /= 1) &
             call msg_fatal ("Stable: listed particles must be unique")
        pdg = pdg_array_get (pa, 1)
        call global%modify_particle (pdg, stable = .true., &
          isotropic_decay = .false., &
          diagonal_decay = .false., &
          polarized = .false.)
        call flv%init (pdg, cmd%local%model)
        call msg_message ("Particle " &
             // char (flv%get_name ()) &
             // " declared as stable")
     end do
   end subroutine cmd_stable_execute
 
 @ %def cmd_stable_execute
 @
 \subsubsection{Polarized particles}
 These commands mark particles as (un)polarized, to be applied in
 subsequent simulation passes.  Since this is technically the same as
 the [[stable]] command, we take a shortcut and make this an extension,
 just overriding methods.
 <<Commands: types>>=
   type, extends (cmd_stable_t) :: cmd_polarized_t
    contains
    <<Commands: cmd polarized: TBP>>
   end type cmd_polarized_t
 
   type, extends (cmd_stable_t) :: cmd_unpolarized_t
    contains
    <<Commands: cmd unpolarized: TBP>>
   end type cmd_unpolarized_t
 
 @ %def cmd_polarized_t cmd_unpolarized_t
 @ Output: we know only the number of particles.
 <<Commands: cmd polarized: TBP>>=
   procedure :: write => cmd_polarized_write
 <<Commands: cmd unpolarized: TBP>>=
   procedure :: write => cmd_unpolarized_write
 <<Commands: procedures>>=
   subroutine cmd_polarized_write (cmd, unit, indent)
     class(cmd_polarized_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,1x,I0)")  "polarized:", size (cmd%pn_pdg)
   end subroutine cmd_polarized_write
 
   subroutine cmd_unpolarized_write (cmd, unit, indent)
     class(cmd_unpolarized_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,1x,I0)")  "unpolarized:", size (cmd%pn_pdg)
   end subroutine cmd_unpolarized_write
 
 @ %def cmd_polarized_write
 @ %def cmd_unpolarized_write
 @ Compile: accounted for by the base command.
 
 Execute: apply the modifications to the current model.
 <<Commands: cmd polarized: TBP>>=
   procedure :: execute => cmd_polarized_execute
 <<Commands: cmd unpolarized: TBP>>=
   procedure :: execute => cmd_unpolarized_execute
 <<Commands: procedures>>=
   subroutine cmd_polarized_execute (cmd, global)
     class(cmd_polarized_t), intent(inout) :: cmd
     type(rt_data_t), target, intent(inout) :: global
     type(var_list_t), pointer :: var_list
     type(pdg_array_t) :: pa
     integer :: pdg
     type(flavor_t) :: flv
     integer :: i
     var_list => cmd%local%get_var_list_ptr ()
     do i = 1, size (cmd%pn_pdg)
        pa = eval_pdg_array (cmd%pn_pdg(i)%ptr, var_list)
        if (pdg_array_get_length (pa) /= 1) &
             call msg_fatal ("Polarized: listed particles must be unique")
        pdg = pdg_array_get (pa, 1)
        call global%modify_particle (pdg, polarized = .true., &
             stable = .true., &
             isotropic_decay = .false., &
             diagonal_decay = .false.)
        call flv%init (pdg, cmd%local%model)
        call msg_message ("Particle " &
             // char (flv%get_name ()) &
             // " declared as polarized")
     end do
   end subroutine cmd_polarized_execute
 
   subroutine cmd_unpolarized_execute (cmd, global)
     class(cmd_unpolarized_t), intent(inout) :: cmd
     type(rt_data_t), target, intent(inout) :: global
     type(var_list_t), pointer :: var_list
     type(pdg_array_t) :: pa
     integer :: pdg
     type(flavor_t) :: flv
     integer :: i
     var_list => cmd%local%get_var_list_ptr ()
     do i = 1, size (cmd%pn_pdg)
        pa = eval_pdg_array (cmd%pn_pdg(i)%ptr, var_list)
        if (pdg_array_get_length (pa) /= 1) &
             call msg_fatal ("Unpolarized: listed particles must be unique")
        pdg = pdg_array_get (pa, 1)
        call global%modify_particle (pdg, polarized = .false., &
             stable = .true., &
             isotropic_decay = .false., &
             diagonal_decay = .false.)
        call flv%init (pdg, cmd%local%model)
        call msg_message ("Particle " &
             // char (flv%get_name ()) &
             // " declared as unpolarized")
     end do
   end subroutine cmd_unpolarized_execute
 
 @ %def cmd_polarized_execute
 @ %def cmd_unpolarized_execute
 @
 \subsubsection{Parameters: formats for event-sample output}
 Specify all event formats that are to be used for output files in the
 subsequent simulation run.  (The raw format is on by default and can be turned
 off here.)
 <<Commands: types>>=
   type, extends (command_t) :: cmd_sample_format_t
      private
      type(string_t), dimension(:), allocatable :: format
    contains
    <<Commands: cmd sample format: TBP>>
   end type cmd_sample_format_t
 
 @ %def cmd_sample_format_t
 @ Output: here, everything is known.
 <<Commands: cmd sample format: TBP>>=
   procedure :: write => cmd_sample_format_write
 <<Commands: procedures>>=
   subroutine cmd_sample_format_write (cmd, unit, indent)
     class(cmd_sample_format_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, i
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)", advance="no")  "sample_format = "
     do i = 1, size (cmd%format)
        if (i > 1)  write (u, "(A,1x)", advance="no")  ","
        write (u, "(A)", advance="no")  char (cmd%format(i))
     end do
     write (u, "(A)")
   end subroutine cmd_sample_format_write
 
 @ %def cmd_sample_format_write
 @ Compile.  Initialize evaluation trees.
 <<Commands: cmd sample format: TBP>>=
   procedure :: compile => cmd_sample_format_compile
 <<Commands: procedures>>=
   subroutine cmd_sample_format_compile (cmd, global)
     class(cmd_sample_format_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg
     type(parse_node_t), pointer :: pn_format
     integer :: i, n_format
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 3)
     if (associated (pn_arg)) then
        n_format = parse_node_get_n_sub (pn_arg)
        allocate (cmd%format (n_format))
        pn_format => parse_node_get_sub_ptr (pn_arg)
        i = 0
        do while (associated (pn_format))
           i = i + 1
           cmd%format(i) = parse_node_get_string (pn_format)
           pn_format => parse_node_get_next_ptr (pn_format)
        end do
     else
        allocate (cmd%format (0))
     end if
   end subroutine cmd_sample_format_compile
 
 @ %def cmd_sample_format_compile
 @ Execute.  Transfer the list of format specifications to the
 corresponding array in the runtime data set.
 <<Commands: cmd sample format: TBP>>=
   procedure :: execute => cmd_sample_format_execute
 <<Commands: procedures>>=
   subroutine cmd_sample_format_execute (cmd, global)
     class(cmd_sample_format_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     if (allocated (global%sample_fmt))  deallocate (global%sample_fmt)
     allocate (global%sample_fmt (size (cmd%format)), source = cmd%format)
   end subroutine cmd_sample_format_execute
 
 @ %def cmd_sample_format_execute
 @
 \subsubsection{The simulate command}
 This is the actual SINDARIN command.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_simulate_t
      ! not private anymore as required by the whizard-c-interface
      integer :: n_proc = 0
      type(string_t), dimension(:), allocatable :: process_id
    contains
    <<Commands: cmd simulate: TBP>>
   end type cmd_simulate_t
 
 @ %def cmd_simulate_t
 @ Output: we know the process IDs.
 <<Commands: cmd simulate: TBP>>=
   procedure :: write => cmd_simulate_write
 <<Commands: procedures>>=
   subroutine cmd_simulate_write (cmd, unit, indent)
     class(cmd_simulate_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, i
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)", advance="no")  "simulate ("
     do i = 1, cmd%n_proc
        if (i > 1)  write (u, "(A,1x)", advance="no")  ","
        write (u, "(A)", advance="no")  char (cmd%process_id(i))
     end do
     write (u, "(A)")  ")"
   end subroutine cmd_simulate_write
 
 @ %def cmd_simulate_write
 @ Compile. In contrast to WHIZARD 1 the confusing option to give the
 number of unweighted events for weighted events as if unweighting were
 to take place has been abandoned. (We both use [[n_events]] for
 weighted and unweighted events, the variable [[n_calls]] from WHIZARD
 1 has been discarded.
 <<Commands: cmd simulate: TBP>>=
   procedure :: compile => cmd_simulate_compile
 <<Commands: procedures>>=
   subroutine cmd_simulate_compile (cmd, global)
     class(cmd_simulate_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_proclist, pn_proc
     integer :: i
     pn_proclist => parse_node_get_sub_ptr (cmd%pn, 2)
     cmd%pn_opt => parse_node_get_next_ptr (pn_proclist)
     call cmd%compile_options (global)
     cmd%n_proc = parse_node_get_n_sub (pn_proclist)
     allocate (cmd%process_id (cmd%n_proc))
     pn_proc => parse_node_get_sub_ptr (pn_proclist)
     do i = 1, cmd%n_proc
        cmd%process_id(i) = parse_node_get_string (pn_proc)
        call global%process_stack%init_result_vars (cmd%process_id(i))
        pn_proc => parse_node_get_next_ptr (pn_proc)
     end do
   end subroutine cmd_simulate_compile
 
 @ %def cmd_simulate_compile
 @ Execute command:  Simulate events.  This is done via a [[simulation_t]]
 object and its associated methods.
 
 Signal handling: the [[generate]] method may exit abnormally if there is a
 pending signal.  The current logic ensures that the [[es_array]] output
 channels are closed before the [[execute]] routine returns.  The program will
 terminate then in [[command_list_execute]].
 <<Commands: cmd simulate: TBP>>=
   procedure :: execute => cmd_simulate_execute
 <<Commands: procedures>>=
   subroutine cmd_simulate_execute (cmd, global)
     class(cmd_simulate_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(rt_data_t), dimension(:), allocatable, target :: alt_env
     integer :: n_events, n_fmt
     type(string_t) :: sample, sample_suffix
     logical :: rebuild_events, read_raw, write_raw
     type(simulation_t), target :: sim
     type(string_t), dimension(:), allocatable :: sample_fmt
     type(event_stream_array_t) :: es_array
     type(event_sample_data_t) :: data
     integer :: i, checkpoint, callback
    <<Commands: cmd simulate execute: variables>>
     var_list => cmd%local%var_list
     if (allocated (cmd%local%pn%alt_setup)) then
        allocate (alt_env (size (cmd%local%pn%alt_setup)))
        do i = 1, size (alt_env)
           call build_alt_setup (alt_env(i), cmd%local, &
                cmd%local%pn%alt_setup(i)%ptr)
        end do
        call sim%init (cmd%process_id, .true., .true., cmd%local, global, &
             alt_env)
     else
        call sim%init (cmd%process_id, .true., .true., cmd%local, global)
     end if
     if (signal_is_pending ())  return
     if (sim%is_valid ()) then
        call sim%init_process_selector ()
        call openmp_set_num_threads_verbose &
             (var_list%get_ival (var_str ("openmp_num_threads")), &
             var_list%get_lval (var_str ("?openmp_logging")))
        call sim%compute_n_events (n_events, var_list)
        sample_suffix = ""
      <<Commands: cmd simulate execute: init>>
        sample = var_list%get_sval (var_str ("$sample"))
        if (sample == "")  then
           sample = sim%get_default_sample_name () // sample_suffix
        else
           sample = var_list%get_sval (var_str ("$sample")) // sample_suffix
        end if
        rebuild_events = &
             var_list%get_lval (var_str ("?rebuild_events"))
        read_raw = &
             var_list%get_lval (var_str ("?read_raw")) &
             .and. .not. rebuild_events
        write_raw = &
             var_list%get_lval (var_str ("?write_raw"))
        checkpoint = &
             var_list%get_ival (var_str ("checkpoint"))
        callback = &
             var_list%get_ival (var_str ("event_callback_interval"))
        if (read_raw) then
           inquire (file = char (sample) // ".evx", exist = read_raw)
        end if
        if (allocated (cmd%local%sample_fmt)) then
           n_fmt = size (cmd%local%sample_fmt)
        else
           n_fmt = 0
        end if
        data = sim%get_data ()
        data%n_evt = n_events
        data%nlo_multiplier = sim%get_n_nlo_entries (1)
        if (read_raw) then
           allocate (sample_fmt (n_fmt))
           if (n_fmt > 0)  sample_fmt = cmd%local%sample_fmt
           call es_array%init (sample, &
                sample_fmt, cmd%local, &
                data = data, &
                input = var_str ("raw"), &
                allow_switch = write_raw, &
                checkpoint = checkpoint, &
                callback = callback)
           call sim%generate (n_events, es_array)
           call es_array%final ()
        else if (write_raw) then
           allocate (sample_fmt (n_fmt + 1))
           if (n_fmt > 0)  sample_fmt(:n_fmt) = cmd%local%sample_fmt
           sample_fmt(n_fmt+1) = var_str ("raw")
           call es_array%init (sample, &
                sample_fmt, cmd%local, &
                data = data, &
                checkpoint = checkpoint, &
                callback = callback)
           call sim%generate (n_events, es_array)
           call es_array%final ()
        else if (allocated (cmd%local%sample_fmt) &
             .or. checkpoint > 0 &
             .or. callback > 0) then
           allocate (sample_fmt (n_fmt))
           if (n_fmt > 0)  sample_fmt = cmd%local%sample_fmt
           call es_array%init (sample, &
                sample_fmt, cmd%local, &
                data = data, &
                checkpoint = checkpoint, &
                callback = callback)
           call sim%generate (n_events, es_array)
           call es_array%final ()
        else
           call sim%generate (n_events)
        end if
        if (allocated (alt_env)) then
           do i = 1, size (alt_env)
              call alt_env(i)%local_final ()
           end do
        end if
     end if
     call sim%final ()
   end subroutine cmd_simulate_execute
 
 @ %def cmd_simulate_execute
 <<Commands: cmd simulate execute: variables>>=
 @
 <<Commands: cmd simulate execute: init>>=
 @
 <<MPI: Commands: cmd simulate execute: variables>>=
   logical :: mpi_logging
   integer :: rank, n_size
 @ Append rank id to sample name.
 <<MPI: Commands: cmd simulate execute: init>>=
   call mpi_get_comm_id (n_size, rank)
   if (n_size > 1) then
      sample_suffix = var_str ("_") // str (rank)
   end if
   mpi_logging = (("vamp2" == char (var_list%get_sval (var_str ("$integration_method"))) &
        & .and. (n_size > 1)) &
        & .or. var_list%get_lval (var_str ("?mpi_logging")))
   call mpi_set_logging (mpi_logging)
 @
 @ Build an alternative setup: the parse tree is stored in the global
 environment.  We create a temporary command list to compile and execute this;
 the result is an alternative local environment [[alt_env]] which we can hand
 over to the [[simulate]] command.
 <<Commands: procedures>>=
   recursive subroutine build_alt_setup (alt_env, global, pn)
     type(rt_data_t), intent(inout), target :: alt_env
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), intent(in), target :: pn
     type(command_list_t), allocatable :: alt_options
     allocate (alt_options)
     call alt_env%local_init (global)
     call alt_env%activate ()
     call alt_options%compile (pn, alt_env)
     call alt_options%execute (alt_env)
     call alt_env%deactivate (global, keep_local = .true.)
     call alt_options%final ()
   end subroutine build_alt_setup
 
 @ %def build_alt_setup
 @
 \subsubsection{The rescan command}
 This is the actual SINDARIN command.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_rescan_t
      ! private
      type(parse_node_t), pointer :: pn_filename => null ()
      integer :: n_proc = 0
      type(string_t), dimension(:), allocatable :: process_id
    contains
    <<Commands: cmd rescan: TBP>>
   end type cmd_rescan_t
 
 @ %def cmd_rescan_t
 @ Output: we know the process IDs.
 <<Commands: cmd rescan: TBP>>=
   procedure :: write => cmd_rescan_write
 <<Commands: procedures>>=
   subroutine cmd_rescan_write (cmd, unit, indent)
     class(cmd_rescan_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, i
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)", advance="no")  "rescan ("
     do i = 1, cmd%n_proc
        if (i > 1)  write (u, "(A,1x)", advance="no")  ","
        write (u, "(A)", advance="no")  char (cmd%process_id(i))
     end do
     write (u, "(A)")  ")"
   end subroutine cmd_rescan_write
 
 @ %def cmd_rescan_write
 @ Compile.  The command takes a suffix argument, namely the file name
 of requested event file.
 <<Commands: cmd rescan: TBP>>=
   procedure :: compile => cmd_rescan_compile
 <<Commands: procedures>>=
   subroutine cmd_rescan_compile (cmd, global)
     class(cmd_rescan_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_filename, pn_proclist, pn_proc
     integer :: i
     pn_filename => parse_node_get_sub_ptr (cmd%pn, 2)
     pn_proclist => parse_node_get_next_ptr (pn_filename)
     cmd%pn_opt => parse_node_get_next_ptr (pn_proclist)
     call cmd%compile_options (global)
     cmd%pn_filename => pn_filename
     cmd%n_proc = parse_node_get_n_sub (pn_proclist)
     allocate (cmd%process_id (cmd%n_proc))
     pn_proc => parse_node_get_sub_ptr (pn_proclist)
     do i = 1, cmd%n_proc
        cmd%process_id(i) = parse_node_get_string (pn_proc)
        pn_proc => parse_node_get_next_ptr (pn_proc)
     end do
   end subroutine cmd_rescan_compile
 
 @ %def cmd_rescan_compile
 @ Execute command:  Rescan events.  This is done via a [[simulation_t]]
 object and its associated methods.
 <<Commands: cmd rescan: TBP>>=
   procedure :: execute => cmd_rescan_execute
 <<Commands: procedures>>=
   subroutine cmd_rescan_execute (cmd, global)
     class(cmd_rescan_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(rt_data_t), dimension(:), allocatable, target :: alt_env
     type(string_t) :: sample, sample_suffix
     logical :: exist, write_raw, update_event, update_sqme
     type(simulation_t), target :: sim
     type(event_sample_data_t) :: input_data, data
     type(string_t) :: input_sample
     integer :: n_fmt
     type(string_t), dimension(:), allocatable :: sample_fmt
     type(string_t) :: input_format, input_ext, input_file
     type(string_t) :: lhef_extension, extension_hepmc, extension_lcio
     type(event_stream_array_t) :: es_array
     integer :: i, n_events
   <<Commands: cmd rescan execute: variables>>
     var_list => cmd%local%var_list
     if (allocated (cmd%local%pn%alt_setup)) then
        allocate (alt_env (size (cmd%local%pn%alt_setup)))
        do i = 1, size (alt_env)
           call build_alt_setup (alt_env(i), cmd%local, &
                cmd%local%pn%alt_setup(i)%ptr)
        end do
        call sim%init (cmd%process_id, .false., .false., cmd%local, global, &
             alt_env)
     else
        call sim%init (cmd%process_id, .false., .false., cmd%local, global)
     end if
     call sim%compute_n_events (n_events, var_list)
     input_sample = eval_string (cmd%pn_filename, var_list)
     input_format = var_list%get_sval (&
          var_str ("$rescan_input_format"))
     sample_suffix = ""
   <<Commands: cmd rescan execute: init>>
     sample = var_list%get_sval (var_str ("$sample"))
     if (sample == "") then
        sample = sim%get_default_sample_name () // sample_suffix
     else
        sample = var_list%get_sval (var_str ("$sample")) // sample_suffix
     end if
     write_raw = var_list%get_lval (var_str ("?write_raw"))
     if (allocated (cmd%local%sample_fmt)) then
        n_fmt = size (cmd%local%sample_fmt)
     else
        n_fmt = 0
     end if
     if (write_raw) then
        if (sample == input_sample) then
           call msg_error ("Rescan: ?write_raw = true: " &
                // "suppressing raw event output (filename clashes with input)")
           allocate (sample_fmt (n_fmt))
           if (n_fmt > 0)  sample_fmt = cmd%local%sample_fmt
        else
           allocate (sample_fmt (n_fmt + 1))
           if (n_fmt > 0)  sample_fmt(:n_fmt) = cmd%local%sample_fmt
           sample_fmt(n_fmt+1) = var_str ("raw")
        end if
     else
        allocate (sample_fmt (n_fmt))
        if (n_fmt > 0)  sample_fmt = cmd%local%sample_fmt
     end if
     update_event = &
          var_list%get_lval (var_str ("?update_event"))
     update_sqme = &
          var_list%get_lval (var_str ("?update_sqme"))
     if (update_event .or. update_sqme) then
        call msg_message ("Recalculating observables")
        if (update_sqme) then
           call msg_message ("Recalculating squared matrix elements")
        end if
     end if
     lhef_extension = &
          var_list%get_sval (var_str ("$lhef_extension"))
     extension_hepmc = &
          var_list%get_sval (var_str ("$extension_hepmc"))
     extension_lcio = &
          var_list%get_sval (var_str ("$extension_lcio"))
     select case (char (input_format))
     case ("raw");  input_ext = "evx"
        call cmd%local%set_log &
             (var_str ("?recover_beams"), .false., is_known=.true.)
     case ("lhef"); input_ext = lhef_extension
     case ("hepmc"); input_ext = extension_hepmc
     case ("lcio"); input_ext = extension_lcio
     case default
        call msg_fatal ("rescan: input sample format '" // char (input_format) &
             // "' not supported")
     end select
     input_file = input_sample // "." // input_ext
     inquire (file = char (input_file), exist = exist)
     if (exist) then
        input_data = sim%get_data (alt = .false.)
        input_data%n_evt = n_events
        data = sim%get_data ()
        data%n_evt = n_events
        input_data%md5sum_cfg = ""
        call es_array%init (sample, &
             sample_fmt, cmd%local, data, &
             input = input_format, input_sample = input_sample, &
             input_data = input_data, &
             allow_switch = .false.)
        call sim%rescan (n_events, es_array, global = cmd%local)
        call es_array%final ()
     else
        call msg_fatal ("Rescan: event file '" &
             // char (input_file) // "' not found")
     end if
     if (allocated (alt_env)) then
        do i = 1, size (alt_env)
           call alt_env(i)%local_final ()
        end do
     end if
     call sim%final ()
   end subroutine cmd_rescan_execute
 
 @ %def cmd_rescan_execute
 @
 <<Commands: cmd rescan execute: variables>>=
 @
 <<Commands: cmd rescan execute: init>>=
 @
 <<MPI: Commands: cmd rescan execute: variables>>=
   logical :: mpi_logging
   integer :: rank, n_size
 @ Append rank id to sample name.
 <<MPI: Commands: cmd rescan execute: init>>=
   call mpi_get_comm_id (n_size, rank)
   if (n_size > 1) then
      sample_suffix = var_str ("_") // str (rank)
   end if
   mpi_logging = (("vamp2" == char (var_list%get_sval (var_str ("$integration_method"))) &
        & .and. (n_size > 1)) &
        & .or. var_list%get_lval (var_str ("?mpi_logging")))
   call mpi_set_logging (mpi_logging)
 @
 \subsubsection{Parameters: number of iterations}
 Specify number of iterations and number of calls for one integration pass.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_iterations_t
      private
      integer :: n_pass = 0
      type(parse_node_p), dimension(:), allocatable :: pn_expr_n_it
      type(parse_node_p), dimension(:), allocatable :: pn_expr_n_calls
      type(parse_node_p), dimension(:), allocatable :: pn_sexpr_adapt
    contains
    <<Commands: cmd iterations: TBP>>
   end type cmd_iterations_t
 
 @ %def cmd_iterations_t
 @ Output.  Display the number of passes, which is known after compilation.
 <<Commands: cmd iterations: TBP>>=
   procedure :: write => cmd_iterations_write
 <<Commands: procedures>>=
   subroutine cmd_iterations_write (cmd, unit, indent)
     class(cmd_iterations_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     select case (cmd%n_pass)
     case (0)
        write (u, "(1x,A)")  "iterations: [empty]"
     case (1)
        write (u, "(1x,A,I0,A)")  "iterations: ", cmd%n_pass, " pass"
     case default
        write (u, "(1x,A,I0,A)")  "iterations: ", cmd%n_pass, " passes"
     end select
   end subroutine cmd_iterations_write
 
 @ %def cmd_iterations_write
 @ Compile.  Initialize evaluation trees.
 <<Commands: cmd iterations: TBP>>=
   procedure :: compile => cmd_iterations_compile
 <<Commands: procedures>>=
   subroutine cmd_iterations_compile (cmd, global)
     class(cmd_iterations_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg, pn_n_it, pn_n_calls, pn_adapt
     type(parse_node_t), pointer :: pn_it_spec, pn_calls_spec, pn_adapt_spec
     integer :: i
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 3)
     if (associated (pn_arg)) then
        cmd%n_pass = parse_node_get_n_sub (pn_arg)
        allocate (cmd%pn_expr_n_it (cmd%n_pass))
        allocate (cmd%pn_expr_n_calls (cmd%n_pass))
        allocate (cmd%pn_sexpr_adapt (cmd%n_pass))
        pn_it_spec => parse_node_get_sub_ptr (pn_arg)
        i = 1
        do while (associated (pn_it_spec))
           pn_n_it => parse_node_get_sub_ptr (pn_it_spec)
           pn_calls_spec => parse_node_get_next_ptr (pn_n_it)
           pn_n_calls => parse_node_get_sub_ptr (pn_calls_spec, 2)
           pn_adapt_spec => parse_node_get_next_ptr (pn_calls_spec)
           if (associated (pn_adapt_spec)) then
              pn_adapt => parse_node_get_sub_ptr (pn_adapt_spec, 2)
           else
              pn_adapt => null ()
           end if
           cmd%pn_expr_n_it(i)%ptr => pn_n_it
           cmd%pn_expr_n_calls(i)%ptr => pn_n_calls
           cmd%pn_sexpr_adapt(i)%ptr => pn_adapt
           i = i + 1
           pn_it_spec => parse_node_get_next_ptr (pn_it_spec)
        end do
     else
        allocate (cmd%pn_expr_n_it (0))
        allocate (cmd%pn_expr_n_calls (0))
     end if
   end subroutine cmd_iterations_compile
 
 @ %def cmd_iterations_compile
 @ Execute.  Evaluate the trees and transfer the results to the iteration
 list in the runtime data set.
 <<Commands: cmd iterations: TBP>>=
   procedure :: execute => cmd_iterations_execute
 <<Commands: procedures>>=
   subroutine cmd_iterations_execute (cmd, global)
     class(cmd_iterations_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     integer, dimension(cmd%n_pass) :: n_it, n_calls
     logical, dimension(cmd%n_pass) :: custom_adapt
     type(string_t), dimension(cmd%n_pass) :: adapt_code
     integer :: i
     var_list => global%get_var_list_ptr ()
     do i = 1, cmd%n_pass
        n_it(i) = eval_int (cmd%pn_expr_n_it(i)%ptr, var_list)
        n_calls(i) = &
             eval_int (cmd%pn_expr_n_calls(i)%ptr, var_list)
        if (associated (cmd%pn_sexpr_adapt(i)%ptr)) then
           adapt_code(i) = &
                eval_string (cmd%pn_sexpr_adapt(i)%ptr, &
                             var_list, is_known = custom_adapt(i))
        else
           custom_adapt(i) = .false.
        end if
     end do
     call global%it_list%init (n_it, n_calls, custom_adapt, adapt_code)
   end subroutine cmd_iterations_execute
 
 @ %def cmd_iterations_execute
 @
 \subsubsection{Range expressions}
 We need a special type for storing and evaluating range expressions.
 <<Commands: parameters>>=
   integer, parameter :: STEP_NONE = 0
   integer, parameter :: STEP_ADD = 1
   integer, parameter :: STEP_SUB = 2
   integer, parameter :: STEP_MUL = 3
   integer, parameter :: STEP_DIV = 4
   integer, parameter :: STEP_COMP_ADD = 11
   integer, parameter :: STEP_COMP_MUL = 13
 @
 There is an abstract base type and two implementations: scan over integers and
 scan over reals.
 <<Commands: types>>=
   type, abstract :: range_t
      type(parse_node_t), pointer :: pn_expr => null ()
      type(parse_node_t), pointer :: pn_term => null ()
      type(parse_node_t), pointer :: pn_factor => null ()
      type(parse_node_t), pointer :: pn_value => null ()
      type(parse_node_t), pointer :: pn_literal => null ()
      type(parse_node_t), pointer :: pn_beg => null ()
      type(parse_node_t), pointer :: pn_end => null ()
      type(parse_node_t), pointer :: pn_step => null ()
      type(eval_tree_t) :: expr_beg
      type(eval_tree_t) :: expr_end
      type(eval_tree_t) :: expr_step
      integer :: step_mode = 0
      integer :: n_step = 0
    contains
    <<Commands: range: TBP>>
   end type range_t
 
 @ %def range_t
 @ These are the implementations:
 <<Commands: types>>=
   type, extends (range_t) :: range_int_t
      integer :: i_beg = 0
      integer :: i_end = 0
      integer :: i_step = 0
    contains
    <<Commands: range int: TBP>>
 end type range_int_t
 
   type, extends (range_t) :: range_real_t
      real(default) :: r_beg = 0
      real(default) :: r_end = 0
      real(default) :: r_step = 0
      real(default) :: lr_beg  = 0
      real(default) :: lr_end  = 0
      real(default) :: lr_step = 0
    contains
    <<Commands: range real: TBP>>
 end type range_real_t
 
 @ %def range_int_t range_real_t
 @ Finalize the allocated dummy node.  The other nodes are just pointers.
 <<Commands: range: TBP>>=
   procedure :: final => range_final
 <<Commands: procedures>>=
   subroutine range_final (object)
     class(range_t), intent(inout) :: object
     if (associated (object%pn_expr)) then
        call parse_node_final (object%pn_expr, recursive = .false.)
        call parse_node_final (object%pn_term, recursive = .false.)
        call parse_node_final (object%pn_factor, recursive = .false.)
        call parse_node_final (object%pn_value, recursive = .false.)
        call parse_node_final (object%pn_literal, recursive = .false.)
        deallocate (object%pn_expr)
        deallocate (object%pn_term)
        deallocate (object%pn_factor)
        deallocate (object%pn_value)
        deallocate (object%pn_literal)
     end if
   end subroutine range_final
 
 @ %def range_final
 @ Output.
 <<Commands: range: TBP>>=
   procedure (range_write), deferred :: write
   procedure :: base_write => range_write
 <<Commands: range int: TBP>>=
   procedure :: write => range_int_write
 <<Commands: range real: TBP>>=
   procedure :: write => range_real_write
 <<Commands: procedures>>=
   subroutine range_write (object, unit)
     class(range_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer :: u
     u = given_output_unit (unit)
     write (u, "(1x,A)")  "Range specification:"
     if (associated (object%pn_expr)) then
        write (u, "(1x,A)")  "Dummy value:"
        call parse_node_write_rec (object%pn_expr, u)
     end if
     if (associated (object%pn_beg)) then
        write (u, "(1x,A)")  "Initial value:"
        call parse_node_write_rec (object%pn_beg, u)
        call object%expr_beg%write (u)
        if (associated (object%pn_end)) then
           write (u, "(1x,A)")  "Final value:"
           call parse_node_write_rec (object%pn_end, u)
           call object%expr_end%write (u)
           if (associated (object%pn_step)) then
              write (u, "(1x,A)")  "Step value:"
              call parse_node_write_rec (object%pn_step, u)
              select case (object%step_mode)
              case (STEP_ADD);   write (u, "(1x,A)")  "Step mode: +"
              case (STEP_SUB);   write (u, "(1x,A)")  "Step mode: -"
              case (STEP_MUL);   write (u, "(1x,A)")  "Step mode: *"
              case (STEP_DIV);   write (u, "(1x,A)")  "Step mode: /"
              case (STEP_COMP_ADD);  write (u, "(1x,A)")  "Division mode: +"
              case (STEP_COMP_MUL);  write (u, "(1x,A)")  "Division mode: *"
              end select
           end if
        end if
     else
        write (u, "(1x,A)")  "Expressions: [undefined]"
     end if
   end subroutine range_write
 
   subroutine range_int_write (object, unit)
     class(range_int_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer :: u
     u = given_output_unit (unit)
     call object%base_write (unit)
     write (u, "(1x,A)")  "Range parameters:"
     write (u, "(3x,A,I0)")  "i_beg  = ", object%i_beg
     write (u, "(3x,A,I0)")  "i_end  = ", object%i_end
     write (u, "(3x,A,I0)")  "i_step = ", object%i_step
     write (u, "(3x,A,I0)")  "n_step = ", object%n_step
   end subroutine range_int_write
 
   subroutine range_real_write (object, unit)
     class(range_real_t), intent(in) :: object
     integer, intent(in), optional :: unit
     integer :: u
     u = given_output_unit (unit)
     call object%base_write (unit)
     write (u, "(1x,A)")  "Range parameters:"
     write (u, "(3x,A," // FMT_19 // ")")  "r_beg  = ", object%r_beg
     write (u, "(3x,A," // FMT_19 // ")")  "r_end  = ", object%r_end
     write (u, "(3x,A," // FMT_19 // ")")  "r_step = ", object%r_end
     write (u, "(3x,A,I0)")  "n_step = ", object%n_step
   end subroutine range_real_write
 
 @ %def range_write
 @ Initialize, given a range expression parse node.  This is common to the
 implementations.
 <<Commands: range: TBP>>=
   procedure :: init => range_init
 <<Commands: procedures>>=
   subroutine range_init (range, pn)
     class(range_t), intent(out) :: range
     type(parse_node_t), intent(in), target :: pn
     type(parse_node_t), pointer :: pn_spec, pn_end, pn_step_spec, pn_op
     select case (char (parse_node_get_rule_key (pn)))
     case ("expr")
     case ("range_expr")
        range%pn_beg => parse_node_get_sub_ptr (pn)
        pn_spec => parse_node_get_next_ptr (range%pn_beg)
        if (associated (pn_spec)) then
           pn_end => parse_node_get_sub_ptr (pn_spec, 2)
           range%pn_end => pn_end
           pn_step_spec => parse_node_get_next_ptr (pn_end)
           if (associated (pn_step_spec)) then
              pn_op => parse_node_get_sub_ptr (pn_step_spec)
              range%pn_step => parse_node_get_next_ptr (pn_op)
              select case (char (parse_node_get_rule_key (pn_op)))
              case ("/+");  range%step_mode = STEP_ADD
              case ("/-");  range%step_mode = STEP_SUB
              case ("/*");  range%step_mode = STEP_MUL
              case ("//");  range%step_mode = STEP_DIV
              case ("/+/");  range%step_mode = STEP_COMP_ADD
              case ("/*/");  range%step_mode = STEP_COMP_MUL
              case default
                 call range%write ()
                 call msg_bug ("Range: step mode not implemented")
              end select
           else
              range%step_mode = STEP_ADD
           end if
        else
           range%step_mode = STEP_NONE
        end if
        call range%create_value_node ()
     case default
        call msg_bug ("range expression: node type '" &
             // char (parse_node_get_rule_key (pn)) &
             // "' not implemented")
     end select
   end subroutine range_init
 
 @ %def range_init
 @ This method manually creates a parse node (actually, a cascade of parse
 nodes) that hold a constant value as a literal.  The idea is that this node is
 inserted as the right-hand side of a fake variable assignment, which is
 prepended to each scan iteration.  Before the variable
 assignment is compiled and executed, we can manually reset the value of the
 literal and thus pretend that the loop variable is assigned this value.
 <<Commands: range: TBP>>=
   procedure :: create_value_node => range_create_value_node
 <<Commands: procedures>>=
   subroutine range_create_value_node (range)
     class(range_t), intent(inout) :: range
     allocate (range%pn_literal)
     allocate (range%pn_value)
     select type (range)
     type is (range_int_t)
        call parse_node_create_value (range%pn_literal, &
             syntax_get_rule_ptr (syntax_cmd_list, var_str ("integer_literal")),&
             ival = 0)
        call parse_node_create_branch (range%pn_value, &
             syntax_get_rule_ptr (syntax_cmd_list, var_str ("integer_value")))
     type is (range_real_t)
        call parse_node_create_value (range%pn_literal, &
             syntax_get_rule_ptr (syntax_cmd_list, var_str ("real_literal")),&
             rval = 0._default)
        call parse_node_create_branch (range%pn_value, &
             syntax_get_rule_ptr (syntax_cmd_list, var_str ("real_value")))
     class default
        call msg_bug ("range: create value node: type not implemented")
     end select
     call parse_node_append_sub (range%pn_value, range%pn_literal)
     call parse_node_freeze_branch (range%pn_value)
     allocate (range%pn_factor)
     call parse_node_create_branch (range%pn_factor, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("factor")))
     call parse_node_append_sub (range%pn_factor, range%pn_value)
     call parse_node_freeze_branch (range%pn_factor)
     allocate (range%pn_term)
     call parse_node_create_branch (range%pn_term, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("term")))
     call parse_node_append_sub (range%pn_term, range%pn_factor)
     call parse_node_freeze_branch (range%pn_term)
     allocate (range%pn_expr)
     call parse_node_create_branch (range%pn_expr, &
          syntax_get_rule_ptr (syntax_cmd_list, var_str ("expr")))
     call parse_node_append_sub (range%pn_expr, range%pn_term)
     call parse_node_freeze_branch (range%pn_expr)
   end subroutine range_create_value_node
 
 @ %def range_create_value_node
 @ Compile, given an environment.
 <<Commands: range: TBP>>=
   procedure :: compile => range_compile
 <<Commands: procedures>>=
   subroutine range_compile (range, global)
     class(range_t), intent(inout) :: range
     type(rt_data_t), intent(in), target :: global
     type(var_list_t), pointer :: var_list
     var_list => global%get_var_list_ptr ()
     if (associated (range%pn_beg)) then
        call range%expr_beg%init_expr (range%pn_beg, var_list)
        if (associated (range%pn_end)) then
           call range%expr_end%init_expr (range%pn_end, var_list)
           if (associated (range%pn_step)) then
              call range%expr_step%init_expr (range%pn_step, var_list)
           end if
        end if
     end if
   end subroutine range_compile
 
 @ %def range_compile
 @ Evaluate: compute the actual bounds and parameters that determine the values
 that we can iterate.
 
 This is implementation-specific.
 <<Commands: range: TBP>>=
   procedure (range_evaluate), deferred :: evaluate
 <<Commands: interfaces>>=
   abstract interface
      subroutine range_evaluate (range)
        import
        class(range_t), intent(inout) :: range
      end subroutine range_evaluate
   end interface
 
 @ %def range_evaluate
 @ The version for an integer variable.  If the step is subtractive, we invert
 the sign and treat it as an additive step.  For a multiplicative step, the
 step must be greater than one, and the initial and final values must be of
 same sign and strictly ordered.  Analogously for a division step.
 <<Commands: range int: TBP>>=
   procedure :: evaluate => range_int_evaluate
 <<Commands: procedures>>=
   subroutine range_int_evaluate (range)
     class(range_int_t), intent(inout) :: range
     integer :: ival
     if (associated (range%pn_beg)) then
        call range%expr_beg%evaluate ()
        if (range%expr_beg%is_known ()) then
           range%i_beg = range%expr_beg%get_int ()
        else
           call range%write ()
           call msg_fatal &
                ("Range expression: initial value evaluates to unknown")
        end if
        if (associated (range%pn_end)) then
           call range%expr_end%evaluate ()
           if (range%expr_end%is_known ()) then
              range%i_end = range%expr_end%get_int ()
              if (associated (range%pn_step)) then
                 call range%expr_step%evaluate ()
                 if (range%expr_step%is_known ()) then
                    range%i_step = range%expr_step%get_int ()
                    select case (range%step_mode)
                    case (STEP_SUB);  range%i_step = - range%i_step
                    end select
                 else
                    call range%write ()
                    call msg_fatal &
                         ("Range expression: step value evaluates to unknown")
                 end if
              else
                 range%i_step = 1
              end if
           else
              call range%write ()
              call msg_fatal &
                   ("Range expression: final value evaluates to unknown")
           end if
        else
           range%i_end = range%i_beg
           range%i_step = 1
        end if
        select case (range%step_mode)
        case (STEP_NONE)
           range%n_step = 1
        case (STEP_ADD, STEP_SUB)
           if (range%i_step /= 0) then
              if (range%i_beg == range%i_end) then
                 range%n_step = 1
              else if (sign (1, range%i_end - range%i_beg) &
                   == sign (1, range%i_step)) then
                 range%n_step = (range%i_end - range%i_beg) / range%i_step + 1
              else
                 range%n_step = 0
              end if
           else
              call msg_fatal ("range evaluation (add): step value is zero")
           end if
        case (STEP_MUL)
           if (range%i_step > 1) then
              if (range%i_beg == range%i_end) then
                 range%n_step = 1
              else if (range%i_beg == 0) then
                 call msg_fatal ("range evaluation (mul): initial value is zero")
              else if (sign (1, range%i_beg) == sign (1, range%i_end) &
                   .and. abs (range%i_beg) < abs (range%i_end)) then
                 range%n_step = 0
                 ival = range%i_beg
                 do while (abs (ival) <= abs (range%i_end))
                    range%n_step = range%n_step + 1
                    ival = ival * range%i_step
                 end do
              else
                 range%n_step = 0
              end if
           else
              call msg_fatal &
                   ("range evaluation (mult): step value is one or less")
           end if
        case (STEP_DIV)
           if (range%i_step > 1) then
              if (range%i_beg == range%i_end) then
                 range%n_step = 1
              else if (sign (1, range%i_beg) == sign (1, range%i_end) &
                   .and. abs (range%i_beg) > abs (range%i_end)) then
                 range%n_step = 0
                 ival = range%i_beg
                 do while (abs (ival) >= abs (range%i_end))
                    range%n_step = range%n_step + 1
                    if (ival == 0)  exit
                    ival = ival / range%i_step
                 end do
              else
                 range%n_step = 0
              end if
           else
              call msg_fatal &
                   ("range evaluation (div): step value is one or less")
           end if
        case (STEP_COMP_ADD)
           call msg_fatal ("range evaluation: &
                &step mode /+/ not allowed for integer variable")
        case (STEP_COMP_MUL)
           call msg_fatal ("range evaluation: &
                &step mode /*/ not allowed for integer variable")
        case default
           call range%write ()
           call msg_bug ("range evaluation: step mode not implemented")
        end select
     end if
   end subroutine range_int_evaluate
 
 @ %def range_int_evaluate
 @ The version for a real variable.
 <<Commands: range real: TBP>>=
   procedure :: evaluate => range_real_evaluate
 <<Commands: procedures>>=
   subroutine range_real_evaluate (range)
     class(range_real_t), intent(inout) :: range
     if (associated (range%pn_beg)) then
        call range%expr_beg%evaluate ()
        if (range%expr_beg%is_known ()) then
           range%r_beg = range%expr_beg%get_real ()
        else
           call range%write ()
           call msg_fatal &
                ("Range expression: initial value evaluates to unknown")
        end if
        if (associated (range%pn_end)) then
           call range%expr_end%evaluate ()
           if (range%expr_end%is_known ()) then
              range%r_end = range%expr_end%get_real ()
              if (associated (range%pn_step)) then
                 if (range%expr_step%is_known ()) then
                    select case (range%step_mode)
                    case (STEP_ADD, STEP_SUB, STEP_MUL, STEP_DIV)
                       call range%expr_step%evaluate ()
                       range%r_step = range%expr_step%get_real ()
                       select case (range%step_mode)
                       case (STEP_SUB);  range%r_step = - range%r_step
                       end select
                    case (STEP_COMP_ADD, STEP_COMP_MUL)
                       range%n_step = &
                            max (range%expr_step%get_int (), 0)
                    end select
                 else
                    call range%write ()
                    call msg_fatal &
                         ("Range expression: step value evaluates to unknown")
                 end if
              else
                 call range%write ()
                 call msg_fatal &
                      ("Range expression (real): step value must be provided")
              end if
           else
              call range%write ()
              call msg_fatal &
                   ("Range expression: final value evaluates to unknown")
           end if
        else
           range%r_end = range%r_beg
           range%r_step = 1
        end if
        select case (range%step_mode)
        case (STEP_NONE)
           range%n_step = 1
        case (STEP_ADD, STEP_SUB)
           if (range%r_step /= 0) then
              if (sign (1._default, range%r_end - range%r_beg) &
                   == sign (1._default, range%r_step)) then
                 range%n_step = &
                      nint ((range%r_end - range%r_beg) / range%r_step + 1)
              else
                 range%n_step = 0
              end if
           else
              call msg_fatal ("range evaluation (add): step value is zero")
           end if
        case (STEP_MUL)
           if (range%r_step > 1) then
              if (range%r_beg == 0 .or. range%r_end == 0) then
                 call msg_fatal ("range evaluation (mul): bound is zero")
              else if (sign (1._default, range%r_beg) &
                   == sign (1._default, range%r_end) &
                   .and. abs (range%r_beg) <= abs (range%r_end)) then
                 range%lr_beg = log (abs (range%r_beg))
                 range%lr_end = log (abs (range%r_end))
                 range%lr_step = log (range%r_step)
                 range%n_step = nint &
                      (abs ((range%lr_end - range%lr_beg) / range%lr_step) + 1)
              else
                 range%n_step = 0
              end if
           else
              call msg_fatal &
                   ("range evaluation (mult): step value is one or less")
           end if
        case (STEP_DIV)
           if (range%r_step > 1) then
              if (range%r_beg == 0 .or. range%r_end == 0) then
                 call msg_fatal ("range evaluation (div): bound is zero")
              else if (sign (1._default, range%r_beg) &
                   == sign (1._default, range%r_end) &
                   .and. abs (range%r_beg) >= abs (range%r_end)) then
                 range%lr_beg = log (abs (range%r_beg))
                 range%lr_end = log (abs (range%r_end))
                 range%lr_step = -log (range%r_step)
                 range%n_step = nint &
                      (abs ((range%lr_end - range%lr_beg) / range%lr_step) + 1)
              else
                 range%n_step = 0
              end if
           else
              call msg_fatal &
                   ("range evaluation (mult): step value is one or less")
           end if
        case (STEP_COMP_ADD)
           ! Number of steps already known
        case (STEP_COMP_MUL)
           ! Number of steps already known
           if (range%r_beg == 0 .or. range%r_end == 0) then
              call msg_fatal ("range evaluation (mul): bound is zero")
           else if (sign (1._default, range%r_beg) &
                == sign (1._default, range%r_end)) then
              range%lr_beg = log (abs (range%r_beg))
              range%lr_end = log (abs (range%r_end))
           else
              range%n_step = 0
           end if
        case default
           call range%write ()
           call msg_bug ("range evaluation: step mode not implemented")
        end select
     end if
   end subroutine range_real_evaluate
 
 @ %def range_real_evaluate
 @ Return the number of iterations:
 <<Commands: range: TBP>>=
   procedure :: get_n_iterations => range_get_n_iterations
 <<Commands: procedures>>=
   function range_get_n_iterations (range) result (n)
     class(range_t), intent(in) :: range
     integer :: n
     n = range%n_step
   end function range_get_n_iterations
 
 @ %def range_get_n_iterations
 @ Compute the value for iteration [[i]] and store it in the embedded token.
 <<Commands: range: TBP>>=
   procedure (range_set_value), deferred :: set_value
 <<Commands: interfaces>>=
   abstract interface
      subroutine range_set_value (range, i)
        import
        class(range_t), intent(inout) :: range
        integer, intent(in) :: i
      end subroutine range_set_value
   end interface
 
 @ %def range_set_value
 @ In the integer case, we compute the value directly for additive step.  For
 multiplicative step, we perform a loop in the same way as above, where the
 number of iteration was determined.
 <<Commands: range int: TBP>>=
   procedure :: set_value => range_int_set_value
 <<Commands: procedures>>=
   subroutine range_int_set_value (range, i)
     class(range_int_t), intent(inout) :: range
     integer, intent(in) :: i
     integer :: k, ival
     select case (range%step_mode)
     case (STEP_NONE)
        ival = range%i_beg
     case (STEP_ADD, STEP_SUB)
        ival = range%i_beg + (i - 1) * range%i_step
     case (STEP_MUL)
        ival = range%i_beg
        do k = 1, i - 1
           ival = ival * range%i_step
        end do
     case (STEP_DIV)
        ival = range%i_beg
        do k = 1, i - 1
           ival = ival / range%i_step
        end do
     case default
        call range%write ()
        call msg_bug ("range iteration: step mode not implemented")
     end select
     call parse_node_set_value (range%pn_literal, ival = ival)
   end subroutine range_int_set_value
 
 @ %def range_int_set_value
 @ In the integer case, we compute the value directly for additive step.  For
 multiplicative step, we perform a loop in the same way as above, where the
 number of iteration was determined.
 <<Commands: range real: TBP>>=
   procedure :: set_value => range_real_set_value
 <<Commands: procedures>>=
   subroutine range_real_set_value (range, i)
     class(range_real_t), intent(inout) :: range
     integer, intent(in) :: i
     real(default) :: rval, x
     select case (range%step_mode)
     case (STEP_NONE)
        rval = range%r_beg
     case (STEP_ADD, STEP_SUB, STEP_COMP_ADD)
        if (range%n_step > 1) then
           x = real (i - 1, default) / (range%n_step - 1)
        else
           x = 1._default / 2
        end if
        rval = x * range%r_end + (1 - x) * range%r_beg
     case (STEP_MUL, STEP_DIV, STEP_COMP_MUL)
        if (range%n_step > 1) then
           x = real (i - 1, default) / (range%n_step - 1)
        else
           x = 1._default / 2
        end if
        rval = sign &
             (exp (x * range%lr_end + (1 - x) * range%lr_beg), range%r_beg)
     case default
        call range%write ()
        call msg_bug ("range iteration: step mode not implemented")
     end select
     call parse_node_set_value (range%pn_literal, rval = rval)
   end subroutine range_real_set_value
 
 @ %def range_real_set_value
 @
 \subsubsection{Scan over parameters and other objects}
 The scan command allocates a new parse node for the variable
 assignment (the lhs).  The rhs of this parse node is assigned from the
 available rhs expressions in the scan list, one at a time, so the
 compiled parse node can be prepended to the scan body.
 
 Note: for the integer/real range array, the obvious implementation as a
 polymorphic array is suspended because in gfortran 4.7, polymorphic arrays are
 apparently broken.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_scan_t
      private
      type(string_t) :: name
      integer :: n_values = 0
      type(parse_node_p), dimension(:), allocatable :: scan_cmd
      !!! !!! gfortran 4.7.x memory corruption
      !!!  class(range_t), dimension(:), allocatable :: range
      type(range_int_t), dimension(:), allocatable :: range_int
      type(range_real_t), dimension(:), allocatable :: range_real
    contains
    <<Commands: cmd scan: TBP>>
   end type cmd_scan_t
 
 @ %def cmd_scan_t
 @ Finalizer.
 
 The auxiliary parse nodes that we have constructed have to be treated
 carefully: the embedded pointers all point to persistent objects
 somewhere else and should not be finalized, so we should not call the
 finalizer recursively.
 <<Commands: cmd scan: TBP>>=
   procedure :: final => cmd_scan_final
 <<Commands: procedures>>=
   recursive subroutine cmd_scan_final (cmd)
     class(cmd_scan_t), intent(inout) :: cmd
     type(parse_node_t), pointer :: pn_var_single, pn_decl_single
     type(string_t) :: key
     integer :: i
     if (allocated (cmd%scan_cmd)) then
        do i = 1, size (cmd%scan_cmd)
           pn_var_single => parse_node_get_sub_ptr (cmd%scan_cmd(i)%ptr)
           key = parse_node_get_rule_key (pn_var_single)
           select case (char (key))
           case ("scan_string_decl", "scan_log_decl")
              pn_decl_single => parse_node_get_sub_ptr (pn_var_single, 2)
              call parse_node_final (pn_decl_single, recursive=.false.)
              deallocate (pn_decl_single)
           end select
           call parse_node_final (pn_var_single, recursive=.false.)
           deallocate (pn_var_single)
        end do
        deallocate (cmd%scan_cmd)
     end if
     !!! !!! gfortran 4.7.x memory corruption
     !!!  if (allocated (cmd%range)) then
     !!!     do i = 1, size (cmd%range)
     !!!        call cmd%range(i)%final ()
     !!!     end do
     !!!  end if
     if (allocated (cmd%range_int)) then
        do i = 1, size (cmd%range_int)
           call cmd%range_int(i)%final ()
        end do
     end if
     if (allocated (cmd%range_real)) then
        do i = 1, size (cmd%range_real)
           call cmd%range_real(i)%final ()
        end do
     end if
   end subroutine cmd_scan_final
 
 @ %def cmd_scan_final
 @ Output.
 <<Commands: cmd scan: TBP>>=
   procedure :: write => cmd_scan_write
 <<Commands: procedures>>=
   subroutine cmd_scan_write (cmd, unit, indent)
     class(cmd_scan_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,1x,A,1x,'(',I0,')')")  "scan:", char (cmd%name), &
          cmd%n_values
   end subroutine cmd_scan_write
 
 @ %def cmd_scan_write
 @ Compile the scan command.  We construct a new parse node that
 implements the variable assignment for a single element on the rhs,
 instead of the whole list that we get from the original parse tree.
 By simply copying the node, we copy all pointers and inherit the
 targets from the original.  During execution, we should replace the
 rhs by the stored rhs pointers (the list elements), one by one, then
 (re)compile the redefined node.
 <<Commands: cmd scan: TBP>>=
   procedure :: compile => cmd_scan_compile
 <<Commands: procedures>>=
   recursive subroutine cmd_scan_compile (cmd, global)
     class(cmd_scan_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     type(parse_node_t), pointer :: pn_var, pn_body, pn_body_first
     type(parse_node_t), pointer :: pn_decl, pn_name
     type(parse_node_t), pointer :: pn_arg, pn_scan_cmd, pn_rhs
     type(parse_node_t), pointer :: pn_decl_single, pn_var_single
     type(syntax_rule_t), pointer :: var_rule_decl, var_rule
     type(string_t) :: key
     integer :: var_type
     integer :: i
     if (debug_on) call msg_debug (D_CORE, "cmd_scan_compile")
     if (debug_active (D_CORE))  call parse_node_write_rec (cmd%pn)
     pn_var => parse_node_get_sub_ptr (cmd%pn, 2)
     pn_body => parse_node_get_next_ptr (pn_var)
     if (associated (pn_body)) then
        pn_body_first => parse_node_get_sub_ptr (pn_body)
     else
        pn_body_first => null ()
     end if
     key = parse_node_get_rule_key (pn_var)
     select case (char (key))
     case ("scan_num")
        pn_name => parse_node_get_sub_ptr (pn_var)
        cmd%name = parse_node_get_string (pn_name)
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, var_str ("cmd_num"))
        pn_arg => parse_node_get_next_ptr (pn_name, 2)
     case ("scan_int")
        pn_name => parse_node_get_sub_ptr (pn_var, 2)
        cmd%name = parse_node_get_string (pn_name)
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, var_str ("cmd_int"))
        pn_arg => parse_node_get_next_ptr (pn_name, 2)
     case ("scan_real")
        pn_name => parse_node_get_sub_ptr (pn_var, 2)
        cmd%name = parse_node_get_string (pn_name)
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, var_str ("cmd_real"))
        pn_arg => parse_node_get_next_ptr (pn_name, 2)
     case ("scan_complex")
        pn_name => parse_node_get_sub_ptr (pn_var, 2)
        cmd%name = parse_node_get_string (pn_name)
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, var_str("cmd_complex"))
        pn_arg => parse_node_get_next_ptr (pn_name, 2)
     case ("scan_alias")
        pn_name => parse_node_get_sub_ptr (pn_var, 2)
        cmd%name = parse_node_get_string (pn_name)
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, var_str ("cmd_alias"))
        pn_arg => parse_node_get_next_ptr (pn_name, 2)
     case ("scan_string_decl")
        pn_decl => parse_node_get_sub_ptr (pn_var, 2)
        pn_name => parse_node_get_sub_ptr (pn_decl, 2)
        cmd%name = parse_node_get_string (pn_name)
        var_rule_decl => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_string"))
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_string_decl"))
        pn_arg => parse_node_get_next_ptr (pn_name, 2)
     case ("scan_log_decl")
        pn_decl => parse_node_get_sub_ptr (pn_var, 2)
        pn_name => parse_node_get_sub_ptr (pn_decl, 2)
        cmd%name = parse_node_get_string (pn_name)
        var_rule_decl => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_log"))
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_log_decl"))
        pn_arg => parse_node_get_next_ptr (pn_name, 2)
     case ("scan_cuts")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_cuts"))
        cmd%name = "cuts"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case ("scan_weight")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_weight"))
        cmd%name = "weight"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case ("scan_scale")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_scale"))
        cmd%name = "scale"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case ("scan_ren_scale")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_ren_scale"))
        cmd%name = "renormalization_scale"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case ("scan_fac_scale")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_fac_scale"))
        cmd%name = "factorization_scale"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case ("scan_selection")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_selection"))
        cmd%name = "selection"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case ("scan_reweight")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_reweight"))
        cmd%name = "reweight"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case ("scan_analysis")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_analysis"))
        cmd%name = "analysis"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case ("scan_model")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_model"))
        cmd%name = "model"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case ("scan_library")
        var_rule => syntax_get_rule_ptr (syntax_cmd_list, &
             var_str ("cmd_library"))
        cmd%name = "library"
        pn_arg => parse_node_get_sub_ptr (pn_var, 3)
     case default
        call msg_bug ("scan: case '" // char (key) // "' not implemented")
     end select
     if (associated (pn_arg)) then
        cmd%n_values = parse_node_get_n_sub (pn_arg)
     end if
     var_list => global%get_var_list_ptr ()
     allocate (cmd%scan_cmd (cmd%n_values))
     select case (char (key))
     case ("scan_num")
        var_type = &
             var_list%get_type (cmd%name)
        select case (var_type)
        case (V_INT)
           !!! !!! gfortran 4.7.x memory corruption
           !!!  allocate (range_int_t :: cmd%range (cmd%n_values))
           allocate (cmd%range_int (cmd%n_values))
        case (V_REAL)
           !!! !!! gfortran 4.7.x memory corruption
           !!!  allocate (range_real_t :: cmd%range (cmd%n_values))
           allocate (cmd%range_real (cmd%n_values))
        case (V_CMPLX)
           call msg_fatal ("scan over complex variable not implemented")
        case (V_NONE)
           call msg_fatal ("scan: variable '" // char (cmd%name) //"' undefined")
        case default
           call msg_bug ("scan: impossible variable type")
        end select
     case ("scan_int")
        !!! !!! gfortran 4.7.x memory corruption
        !!!  allocate (range_int_t :: cmd%range (cmd%n_values))
        allocate (cmd%range_int (cmd%n_values))
     case ("scan_real")
        !!! !!! gfortran 4.7.x memory corruption
        !!!  allocate (range_real_t :: cmd%range (cmd%n_values))
        allocate (cmd%range_real (cmd%n_values))
     case ("scan_complex")
        call msg_fatal ("scan over complex variable not implemented")
     end select
     i = 1
     if (associated (pn_arg)) then
        pn_rhs => parse_node_get_sub_ptr (pn_arg)
     else
        pn_rhs => null ()
     end if
     do while (associated (pn_rhs))
        allocate (pn_scan_cmd)
        call parse_node_create_branch (pn_scan_cmd, &
             syntax_get_rule_ptr (syntax_cmd_list, var_str ("command_list")))
        allocate (pn_var_single)
        pn_var_single = pn_var
        call parse_node_replace_rule (pn_var_single, var_rule)
        select case (char (key))
        case ("scan_num", "scan_int", "scan_real", &
             "scan_complex", "scan_alias", &
             "scan_cuts", "scan_weight", &
             "scan_scale", "scan_ren_scale", "scan_fac_scale", &
             "scan_selection", "scan_reweight", "scan_analysis", &
             "scan_model", "scan_library")
           if (allocated (cmd%range_int)) then
              call cmd%range_int(i)%init (pn_rhs)
              !!! !!! gfortran 4.7.x memory corruption
              !!!  call cmd%range_int(i)%compile (global)
              call parse_node_replace_last_sub &
                   (pn_var_single, cmd%range_int(i)%pn_expr)
           else if (allocated (cmd%range_real)) then
              call cmd%range_real(i)%init (pn_rhs)
              !!! !!! gfortran 4.7.x memory corruption
              !!!  call cmd%range_real(i)%compile (global)
              call parse_node_replace_last_sub &
                   (pn_var_single, cmd%range_real(i)%pn_expr)
           else
              call parse_node_replace_last_sub (pn_var_single, pn_rhs)
           end if
        case ("scan_string_decl", "scan_log_decl")
           allocate (pn_decl_single)
           pn_decl_single = pn_decl
           call parse_node_replace_rule (pn_decl_single, var_rule_decl)
           call parse_node_replace_last_sub (pn_decl_single, pn_rhs)
           call parse_node_freeze_branch (pn_decl_single)
           call parse_node_replace_last_sub (pn_var_single, pn_decl_single)
        case default
           call msg_bug ("scan: case '" // char (key)  &
                // "' broken")
        end select
        call parse_node_freeze_branch (pn_var_single)
        call parse_node_append_sub (pn_scan_cmd, pn_var_single)
        call parse_node_append_sub (pn_scan_cmd, pn_body_first)
        call parse_node_freeze_branch (pn_scan_cmd)
        cmd%scan_cmd(i)%ptr => pn_scan_cmd
        i = i + 1
        pn_rhs => parse_node_get_next_ptr (pn_rhs)
     end do
     if (debug_active (D_CORE)) then
        do i = 1, cmd%n_values
           print *, "scan command ", i
           call parse_node_write_rec (cmd%scan_cmd(i)%ptr)
           if (allocated (cmd%range_int))  call cmd%range_int(i)%write ()
           if (allocated (cmd%range_real))  call cmd%range_real(i)%write ()
        end do
        print *, "original"
        call parse_node_write_rec (cmd%pn)
     end if
   end subroutine cmd_scan_compile
 
 @ %def cmd_scan_compile
 @ Execute the loop for all values in the step list.  We use the
 parse trees with single variable assignment that we have stored, to
 iteratively create a local environment, execute the stored commands, and
 destroy it again.  When we encounter a range object, we execute the commands
 for each value that this object provides.  Computing this value has the side
 effect of modifying the rhs of the variable assignment that heads the local
 command list, directly in the local parse tree.
 <<Commands: cmd scan: TBP>>=
   procedure :: execute => cmd_scan_execute
 <<Commands: procedures>>=
   recursive subroutine cmd_scan_execute (cmd, global)
     class(cmd_scan_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(rt_data_t), allocatable :: local
     integer :: i, j
     do i = 1, cmd%n_values
        if (allocated (cmd%range_int)) then
           call cmd%range_int(i)%compile (global)
           call cmd%range_int(i)%evaluate ()
           do j = 1, cmd%range_int(i)%get_n_iterations ()
              call cmd%range_int(i)%set_value (j)
              allocate (local)
              call build_alt_setup (local, global, cmd%scan_cmd(i)%ptr)
              call local%local_final ()
              deallocate (local)
           end do
        else if (allocated (cmd%range_real)) then
           call cmd%range_real(i)%compile (global)
           call cmd%range_real(i)%evaluate ()
           do j = 1, cmd%range_real(i)%get_n_iterations ()
              call cmd%range_real(i)%set_value (j)
              allocate (local)
              call build_alt_setup (local, global, cmd%scan_cmd(i)%ptr)
              call local%local_final ()
              deallocate (local)
           end do
        else
           allocate (local)
           call build_alt_setup (local, global, cmd%scan_cmd(i)%ptr)
           call local%local_final ()
           deallocate (local)
        end if
     end do
   end subroutine cmd_scan_execute
 
 @ %def cmd_scan_execute
 @
 \subsubsection{Conditionals}
 Conditionals are implemented as a list that is compiled and evaluated
 recursively; this allows for a straightforward representation of
 [[else if]] constructs.  A [[cmd_if_t]] object can hold either an
 [[else_if]] clause which is another object of this type, or an
 [[else_body]], but not both.
 
 If- or else-bodies are no scoping units, so all data remain global and
 no copy-in copy-out is needed.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_if_t
      private
      type(parse_node_t), pointer :: pn_if_lexpr => null ()
      type(command_list_t), pointer :: if_body => null ()
      type(cmd_if_t), dimension(:), pointer :: elsif_cmd => null ()
      type(command_list_t), pointer :: else_body => null ()
    contains
    <<Commands: cmd if: TBP>>
   end type cmd_if_t
 
 @ %def cmd_if_t
 @ Finalizer.  There are no local options, therefore we can simply override
 the default finalizer.
 <<Commands: cmd if: TBP>>=
   procedure :: final => cmd_if_final
 <<Commands: procedures>>=
   recursive subroutine cmd_if_final (cmd)
     class(cmd_if_t), intent(inout) :: cmd
     integer :: i
     if (associated (cmd%if_body)) then
        call command_list_final (cmd%if_body)
        deallocate (cmd%if_body)
     end if
     if (associated (cmd%elsif_cmd)) then
        do i = 1, size (cmd%elsif_cmd)
           call cmd_if_final (cmd%elsif_cmd(i))
        end do
        deallocate (cmd%elsif_cmd)
     end if
     if (associated (cmd%else_body)) then
        call command_list_final (cmd%else_body)
        deallocate (cmd%else_body)
     end if
   end subroutine cmd_if_final
 
 @ %def cmd_if_final
 @ Output.  Recursively write the command lists.
 <<Commands: cmd if: TBP>>=
   procedure :: write => cmd_if_write
 <<Commands: procedures>>=
   subroutine cmd_if_write (cmd, unit, indent)
     class(cmd_if_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, ind, i
     u = given_output_unit (unit);  if (u < 0)  return
     ind = 0;  if (present (indent))  ind = indent
     call write_indent (u, indent)
     write (u, "(A)")  "if <expr> then"
     if (associated (cmd%if_body)) then
        call cmd%if_body%write (unit, ind + 1)
     end if
     if (associated (cmd%elsif_cmd)) then
        do i = 1, size (cmd%elsif_cmd)
           call write_indent (u, indent)
           write (u, "(A)")  "elsif <expr> then"
           if (associated (cmd%elsif_cmd(i)%if_body)) then
              call cmd%elsif_cmd(i)%if_body%write (unit, ind + 1)
           end if
        end do
     end if
     if (associated (cmd%else_body)) then
        call write_indent (u, indent)
        write (u, "(A)")  "else"
        call cmd%else_body%write (unit, ind + 1)
     end if
   end subroutine cmd_if_write
 
 @ %def cmd_if_write
 @ Compile the conditional.
 <<Commands: cmd if: TBP>>=
   procedure :: compile => cmd_if_compile
 <<Commands: procedures>>=
   recursive subroutine cmd_if_compile (cmd, global)
     class(cmd_if_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_lexpr, pn_body
     type(parse_node_t), pointer :: pn_elsif_clauses, pn_cmd_elsif
     type(parse_node_t), pointer :: pn_else_clause, pn_cmd_else
     integer :: i, n_elsif
     pn_lexpr => parse_node_get_sub_ptr (cmd%pn, 2)
     cmd%pn_if_lexpr => pn_lexpr
     pn_body => parse_node_get_next_ptr (pn_lexpr, 2)
     select case (char (parse_node_get_rule_key (pn_body)))
     case ("command_list")
        allocate (cmd%if_body)
        call cmd%if_body%compile (pn_body, global)
        pn_elsif_clauses => parse_node_get_next_ptr (pn_body)
     case default
        pn_elsif_clauses => pn_body
     end select
     select case (char (parse_node_get_rule_key (pn_elsif_clauses)))
     case ("elsif_clauses")
        n_elsif = parse_node_get_n_sub (pn_elsif_clauses)
        allocate (cmd%elsif_cmd (n_elsif))
        pn_cmd_elsif => parse_node_get_sub_ptr (pn_elsif_clauses)
        do i = 1, n_elsif
           pn_lexpr => parse_node_get_sub_ptr (pn_cmd_elsif, 2)
           cmd%elsif_cmd(i)%pn_if_lexpr => pn_lexpr
           pn_body => parse_node_get_next_ptr (pn_lexpr, 2)
           if (associated (pn_body)) then
              allocate (cmd%elsif_cmd(i)%if_body)
              call cmd%elsif_cmd(i)%if_body%compile (pn_body, global)
           end if
           pn_cmd_elsif => parse_node_get_next_ptr (pn_cmd_elsif)
        end do
        pn_else_clause => parse_node_get_next_ptr (pn_elsif_clauses)
     case default
        pn_else_clause => pn_elsif_clauses
     end select
     select case (char (parse_node_get_rule_key (pn_else_clause)))
     case ("else_clause")
        pn_cmd_else => parse_node_get_sub_ptr (pn_else_clause)
        pn_body => parse_node_get_sub_ptr (pn_cmd_else, 2)
        if (associated (pn_body)) then
           allocate (cmd%else_body)
           call cmd%else_body%compile (pn_body, global)
        end if
     end select
   end subroutine cmd_if_compile
 
 @ %def global
 @ (Recursively) execute the condition.  Context remains global in all cases.
 <<Commands: cmd if: TBP>>=
   procedure :: execute => cmd_if_execute
 <<Commands: procedures>>=
   recursive subroutine cmd_if_execute (cmd, global)
     class(cmd_if_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     logical :: lval, is_known
     integer :: i
     var_list => global%get_var_list_ptr ()
     lval = eval_log (cmd%pn_if_lexpr, var_list, is_known=is_known)
     if (is_known) then
        if (lval) then
           if (associated (cmd%if_body)) then
              call cmd%if_body%execute (global)
           end if
           return
        end if
     else
        call error_undecided ()
        return
     end if
     if (associated (cmd%elsif_cmd)) then
        SCAN_ELSIF: do i = 1, size (cmd%elsif_cmd)
           lval = eval_log (cmd%elsif_cmd(i)%pn_if_lexpr, var_list, &
                 is_known=is_known)
           if (is_known) then
              if (lval) then
                 if (associated (cmd%elsif_cmd(i)%if_body)) then
                    call cmd%elsif_cmd(i)%if_body%execute (global)
                 end if
                 return
              end if
           else
              call error_undecided ()
              return
           end if
        end do SCAN_ELSIF
     end if
     if (associated (cmd%else_body)) then
        call cmd%else_body%execute (global)
     end if
   contains
     subroutine error_undecided ()
       call msg_error ("Undefined result of cmditional expression: " &
            // "neither branch will be executed")
     end subroutine error_undecided
   end subroutine cmd_if_execute
 
 @ %def cmd_if_execute
 @
 \subsubsection{Include another command-list file}
 The include command allocates a local parse tree.  This must not be
 deleted before the command object itself is deleted, since pointers
 may point to subobjects of it.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_include_t
      private
      type(string_t) :: file
      type(command_list_t), pointer :: command_list => null ()
      type(parse_tree_t) :: parse_tree
    contains
    <<Commands: cmd include: TBP>>
   end type cmd_include_t
 
 @ %def cmd_include_t
 @ Finalizer: delete the command list.  No options, so we can simply override
 the default finalizer.
 <<Commands: cmd include: TBP>>=
   procedure :: final => cmd_include_final
 <<Commands: procedures>>=
   subroutine cmd_include_final (cmd)
     class(cmd_include_t), intent(inout) :: cmd
     call parse_tree_final (cmd%parse_tree)
     if (associated (cmd%command_list)) then
        call cmd%command_list%final ()
        deallocate (cmd%command_list)
     end if
   end subroutine cmd_include_final
 
 @ %def cmd_include_final
 @ Write: display the command list as-is, if allocated.
 <<Commands: cmd include: TBP>>=
   procedure :: write => cmd_include_write
 <<Commands: procedures>>=
   subroutine cmd_include_write (cmd, unit, indent)
     class(cmd_include_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, ind
     u = given_output_unit (unit)
     ind = 0;  if (present (indent))  ind = indent
     call write_indent (u, indent)
     write (u, "(A,A,A,A)")  "include ", '"', char (cmd%file), '"'
     if (associated (cmd%command_list)) then
        call cmd%command_list%write (u, ind + 1)
     end if
   end subroutine cmd_include_write
 
 @ %def cmd_include_write
 @ Compile file contents: First parse the file, then immediately
 compile its contents.  Use the global data set.
 <<Commands: cmd include: TBP>>=
   procedure :: compile => cmd_include_compile
 <<Commands: procedures>>=
   subroutine cmd_include_compile (cmd, global)
     class(cmd_include_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg, pn_file
     type(string_t) :: file
     logical :: exist
     integer :: u
     type(stream_t), target :: stream
     type(lexer_t) :: lexer
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 2)
     pn_file => parse_node_get_sub_ptr (pn_arg)
     file = parse_node_get_string (pn_file)
     inquire (file=char(file), exist=exist)
     if (exist) then
        cmd%file = file
     else
        cmd%file = global%os_data%whizard_cutspath // "/" // file
        inquire (file=char(cmd%file), exist=exist)
        if (.not. exist) then
           call msg_error ("Include file '" // char (file) // "' not found")
           return
        end if
     end if
     u = free_unit ()
     call lexer_init_cmd_list (lexer, global%lexer)
     call stream_init (stream, char (cmd%file))
     call lexer_assign_stream (lexer, stream)
     call parse_tree_init (cmd%parse_tree, syntax_cmd_list, lexer)
     call stream_final (stream)
     call lexer_final (lexer)
     close (u)
     allocate (cmd%command_list)
     call cmd%command_list%compile (cmd%parse_tree%get_root_ptr (), &
          global)
   end subroutine cmd_include_compile
 
 @ %def cmd_include_compile
 @ Execute file contents in the global context.
 <<Commands: cmd include: TBP>>=
   procedure :: execute => cmd_include_execute
 <<Commands: procedures>>=
   subroutine cmd_include_execute (cmd, global)
     class(cmd_include_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     if (associated (cmd%command_list)) then
        call msg_message &
             ("Including Sindarin from '" // char (cmd%file) // "'")
        call cmd%command_list%execute (global)
        call msg_message &
             ("End of included '" // char (cmd%file) // "'")
     end if
   end subroutine cmd_include_execute
 
 @ %def cmd_include_execute
 @
 \subsubsection{Export values}
 This command exports the current values of variables or other objects to the
 surrounding scope.  By default, a scope enclosed by braces keeps all objects
 local to it.  The [[export]] command exports the values that are generated
 within the scope to the corresponding object in the outer scope.
 
 The allowed set of exportable objects is, in principle, the same as the set of
 objects that the [[show]] command supports.  This includes some convenience
 abbreviations.
 
 TODO: The initial implementation inherits syntax from [[show]], but supports
 only the [[results]] pseudo-object.  The results (i.e., the process stack) is
 appended to the outer process stack instead of being discarded.  The behavior
 of the [[export]] command for other object kinds is to be defined on a
 case-by-case basis.  It may involve replacing the outer value or, instead,
 doing some sort of appending or reduction.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_export_t
      private
      type(string_t), dimension(:), allocatable :: name
    contains
    <<Commands: cmd export: TBP>>
   end type cmd_export_t
 
 @ %def cmd_export_t
 @ Output: list the object names, not values.
 <<Commands: cmd export: TBP>>=
   procedure :: write => cmd_export_write
 <<Commands: procedures>>=
   subroutine cmd_export_write (cmd, unit, indent)
     class(cmd_export_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u, i
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A)", advance="no")  "export: "
     if (allocated (cmd%name)) then
        do i = 1, size (cmd%name)
           write (u, "(1x,A)", advance="no")  char (cmd%name(i))
        end do
        write (u, *)
     else
        write (u, "(5x,A)")  "[undefined]"
     end if
   end subroutine cmd_export_write
 
 @ %def cmd_export_write
 @ Compile.  Allocate an array which is filled with the names of the
 variables to export.
 <<Commands: cmd export: TBP>>=
   procedure :: compile => cmd_export_compile
 <<Commands: procedures>>=
   subroutine cmd_export_compile (cmd, global)
     class(cmd_export_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg, pn_var, pn_prefix, pn_name
     type(string_t) :: key
     integer :: i, n_args
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 2)
     if (associated (pn_arg)) then
        select case (char (parse_node_get_rule_key (pn_arg)))
        case ("show_arg")
           cmd%pn_opt => parse_node_get_next_ptr (pn_arg)
        case default
           cmd%pn_opt => pn_arg
           pn_arg => null ()
        end select
     end if
     call cmd%compile_options (global)
     if (associated (pn_arg)) then
        n_args = parse_node_get_n_sub (pn_arg)
        allocate (cmd%name (n_args))
        pn_var => parse_node_get_sub_ptr (pn_arg)
        i = 0
        do while (associated (pn_var))
           i = i + 1
           select case (char (parse_node_get_rule_key (pn_var)))
           case ("model", "library", "beams", "iterations", &
                 "cuts", "weight", "int", "real", "complex", &
                 "scale", "factorization_scale", "renormalization_scale", &
                 "selection", "reweight", "analysis", "pdg", &
                 "stable", "unstable", "polarized", "unpolarized", &
                 "results", "expect", "intrinsic", "string", "logical")
              cmd%name(i) = parse_node_get_key (pn_var)
           case ("result_var")
              pn_prefix => parse_node_get_sub_ptr (pn_var)
              pn_name => parse_node_get_next_ptr (pn_prefix)
              if (associated (pn_name)) then
                 cmd%name(i) = parse_node_get_key (pn_prefix) &
                      // "(" // parse_node_get_string (pn_name) // ")"
              else
                 cmd%name(i) = parse_node_get_key (pn_prefix)
              end if
           case ("log_var", "string_var", "alias_var")
              pn_prefix => parse_node_get_sub_ptr (pn_var)
              pn_name => parse_node_get_next_ptr (pn_prefix)
              key = parse_node_get_key (pn_prefix)
              if (associated (pn_name)) then
                 select case (char (parse_node_get_rule_key (pn_name)))
                 case ("var_name")
                    select case (char (key))
                    case ("?", "$")  ! $ sign
                       cmd%name(i) = key // parse_node_get_string (pn_name)
                    case ("alias")
                       cmd%name(i) = parse_node_get_string (pn_name)
                    end select
                 case default
                    call parse_node_mismatch &
                         ("var_name",  pn_name)
                 end select
              else
                 cmd%name(i) = key
              end if
           case default
              cmd%name(i) = parse_node_get_string (pn_var)
           end select
           !!! restriction imposed by current lack of implementation
           select case (char (parse_node_get_rule_key (pn_var)))
           case ("results")
           case default
              call msg_fatal ("export: object (type) '" &
                   // char (parse_node_get_rule_key (pn_var)) &
                   // "' not supported yet")
           end select
           pn_var => parse_node_get_next_ptr (pn_var)
        end do
     else
        allocate (cmd%name (0))
     end if
   end subroutine cmd_export_compile
 
 @ %def cmd_export_compile
 @ Execute.  Scan the list of objects to export.
 <<Commands: cmd export: TBP>>=
   procedure :: execute => cmd_export_execute
 <<Commands: procedures>>=
   subroutine cmd_export_execute (cmd, global)
     class(cmd_export_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     call global%append_exports (cmd%name)
   end subroutine cmd_export_execute
 
 @ %def cmd_export_execute
 @
 \subsubsection{Quit command execution}
 The code is the return code of the whole program if it is terminated
 by this command.
 <<Commands: types>>=
   type, extends (command_t) :: cmd_quit_t
      private
      logical :: has_code = .false.
      type(parse_node_t), pointer :: pn_code_expr => null ()
    contains
    <<Commands: cmd quit: TBP>>
   end type cmd_quit_t
 
 @ %def cmd_quit_t
 @ Output.
 <<Commands: cmd quit: TBP>>=
   procedure :: write => cmd_quit_write
 <<Commands: procedures>>=
   subroutine cmd_quit_write (cmd, unit, indent)
     class(cmd_quit_t), intent(in) :: cmd
     integer, intent(in), optional :: unit, indent
     integer :: u
     u = given_output_unit (unit);  if (u < 0)  return
     call write_indent (u, indent)
     write (u, "(1x,A,L1)")  "quit: has_code = ", cmd%has_code
   end subroutine cmd_quit_write
 
 @ %def cmd_quit_write
 @ Compile: allocate a [[quit]] object which serves as a placeholder.
 <<Commands: cmd quit: TBP>>=
   procedure :: compile => cmd_quit_compile
 <<Commands: procedures>>=
   subroutine cmd_quit_compile (cmd, global)
     class(cmd_quit_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_arg
     pn_arg => parse_node_get_sub_ptr (cmd%pn, 2)
     if (associated (pn_arg)) then
        cmd%pn_code_expr => parse_node_get_sub_ptr (pn_arg)
        cmd%has_code = .true.
     end if
   end subroutine cmd_quit_compile
 
 @ %def cmd_quit_compile
 @ Execute: The quit command does not execute anything, it just stops
 command execution.  This is achieved by setting quit flag and quit
 code in the global variable list.  However, the return code, if
 present, is an expression which has to be evaluated.
 <<Commands: cmd quit: TBP>>=
   procedure :: execute => cmd_quit_execute
 <<Commands: procedures>>=
   subroutine cmd_quit_execute (cmd, global)
     class(cmd_quit_t), intent(inout) :: cmd
     type(rt_data_t), intent(inout), target :: global
     type(var_list_t), pointer :: var_list
     logical :: is_known
     var_list => global%get_var_list_ptr ()
     if (cmd%has_code) then
        global%quit_code = eval_int (cmd%pn_code_expr, var_list, &
             is_known=is_known)
        if (.not. is_known) then
           call msg_error ("Undefined return code of quit/exit command")
        end if
     end if
     global%quit = .true.
   end subroutine cmd_quit_execute
 
 @ %def cmd_quit_execute
 @
 \subsection{The command list}
 The command list holds a list of commands and relevant global data.
 <<Commands: public>>=
   public :: command_list_t
 <<Commands: types>>=
   type :: command_list_t
      ! not private anymore as required by the whizard-c-interface
      class(command_t), pointer :: first => null ()
      class(command_t), pointer :: last => null ()
    contains
    <<Commands: command list: TBP>>
   end type command_list_t
 
 @ %def command_list_t
 @ Output.
 <<Commands: command list: TBP>>=
   procedure :: write => command_list_write
 <<Commands: procedures>>=
   recursive subroutine command_list_write (cmd_list, unit, indent)
     class(command_list_t), intent(in) :: cmd_list
     integer, intent(in), optional :: unit, indent
     class(command_t), pointer :: cmd
     cmd => cmd_list%first
     do while (associated (cmd))
        call cmd%write (unit, indent)
        cmd => cmd%next
     end do
   end subroutine command_list_write
 
 @ %def command_list_write
 @ Append a new command to the list and free the original pointer.
 <<Commands: command list: TBP>>=
   procedure :: append => command_list_append
 <<Commands: procedures>>=
   subroutine command_list_append (cmd_list, command)
     class(command_list_t), intent(inout) :: cmd_list
     class(command_t), intent(inout), pointer :: command
     if (associated (cmd_list%last)) then
        cmd_list%last%next => command
     else
        cmd_list%first => command
     end if
     cmd_list%last => command
     command => null ()
   end subroutine command_list_append
 
 @ %def command_list_append
 @ Finalize.
 <<Commands: command list: TBP>>=
   procedure :: final => command_list_final
 <<Commands: procedures>>=
   recursive subroutine command_list_final (cmd_list)
     class(command_list_t), intent(inout) :: cmd_list
     class(command_t), pointer :: command
     do while (associated (cmd_list%first))
        command => cmd_list%first
        cmd_list%first => cmd_list%first%next
        call command%final ()
        deallocate (command)
     end do
     cmd_list%last => null ()
   end subroutine command_list_final
 
 @ %def command_list_final
 @
 \subsection{Compiling the parse tree}
 Transform a parse tree into a command list.  Initialization is assumed
 to be done.
 
 After each command, we set a breakpoint.
 <<Commands: command list: TBP>>=
   procedure :: compile => command_list_compile
 <<Commands: procedures>>=
   recursive subroutine command_list_compile (cmd_list, pn, global)
     class(command_list_t), intent(inout), target :: cmd_list
     type(parse_node_t), intent(in), target :: pn
     type(rt_data_t), intent(inout), target :: global
     type(parse_node_t), pointer :: pn_cmd
     class(command_t), pointer :: command
     integer :: i
     pn_cmd => parse_node_get_sub_ptr (pn)
     do i = 1, parse_node_get_n_sub (pn)
        call dispatch_command (command, pn_cmd)
        call command%compile (global)
        call cmd_list%append (command)
        call terminate_now_if_signal ()
        pn_cmd => parse_node_get_next_ptr (pn_cmd)
     end do
   end subroutine command_list_compile
 
 @ %def command_list_compile
 @
 \subsection{Executing the command list}
 Before executing a command we should execute its options (if any).  After
 that, reset the options, i.e., remove temporary effects from the global
 state.
 
 Also here, after each command we set a breakpoint.
 <<Commands: command list: TBP>>=
   procedure :: execute => command_list_execute
 <<Commands: procedures>>=
   recursive subroutine command_list_execute (cmd_list, global)
     class(command_list_t), intent(in) :: cmd_list
     type(rt_data_t), intent(inout), target :: global
     class(command_t), pointer :: command
     command => cmd_list%first
     COMMAND_COND: do while (associated (command))
        call command%execute_options (global)
        call command%execute (global)
        call command%reset_options (global)
        call terminate_now_if_signal ()
        if (global%quit)  exit COMMAND_COND
        command => command%next
     end do COMMAND_COND
   end subroutine command_list_execute
 
 @ %def command_list_execute
 @
 \subsection{Command list syntax}
 <<Commands: public>>=
   public :: syntax_cmd_list
 <<Commands: variables>>=
   type(syntax_t), target, save :: syntax_cmd_list
 
 @ %def syntax_cmd_list
 <<Commands: public>>=
   public :: syntax_cmd_list_init
 <<Commands: procedures>>=
   subroutine syntax_cmd_list_init ()
     type(ifile_t) :: ifile
     call define_cmd_list_syntax (ifile)
     call syntax_init (syntax_cmd_list, ifile)
     call ifile_final (ifile)
   end subroutine syntax_cmd_list_init
 
 @ %def syntax_cmd_list_init
 <<Commands: public>>=
   public :: syntax_cmd_list_final
 <<Commands: procedures>>=
   subroutine syntax_cmd_list_final ()
     call syntax_final (syntax_cmd_list)
   end subroutine syntax_cmd_list_final
 
 @ %def syntax_cmd_list_final
 <<Commands: public>>=
   public :: syntax_cmd_list_write
 <<Commands: procedures>>=
   subroutine syntax_cmd_list_write (unit)
     integer, intent(in), optional :: unit
     call syntax_write (syntax_cmd_list, unit)
   end subroutine syntax_cmd_list_write
 
 @ %def syntax_cmd_list_write
 <<Commands: procedures>>=
   subroutine define_cmd_list_syntax (ifile)
     type(ifile_t), intent(inout) :: ifile
     call ifile_append (ifile, "SEQ command_list = command*")
     call ifile_append (ifile, "ALT command = " &
          // "cmd_model | cmd_library | cmd_iterations | cmd_sample_format | " &
          // "cmd_var | cmd_slha | " &
          // "cmd_show | cmd_clear | " &
          // "cmd_expect | " &
          // "cmd_cuts | cmd_scale | cmd_fac_scale | cmd_ren_scale | " &
          // "cmd_weight | cmd_selection | cmd_reweight | " &
          // "cmd_beams | cmd_beams_pol_density | cmd_beams_pol_fraction | " &
          // "cmd_beams_momentum | cmd_beams_theta | cmd_beams_phi | " &
          // "cmd_integrate | " &
          // "cmd_observable | cmd_histogram | cmd_plot | cmd_graph | " &
          // "cmd_record | " &
          // "cmd_analysis | cmd_alt_setup | " &
          // "cmd_unstable | cmd_stable | cmd_simulate | cmd_rescan | " &
          // "cmd_process | cmd_compile | cmd_exec | " &
          // "cmd_scan | cmd_if | cmd_include | cmd_quit | " &
          // "cmd_export | " &
          // "cmd_polarized | cmd_unpolarized | " &
          // "cmd_open_out | cmd_close_out | cmd_printf | " &
          // "cmd_write_analysis | cmd_compile_analysis | cmd_nlo | cmd_components")
     call ifile_append (ifile, "GRO options = '{' local_command_list '}'")
     call ifile_append (ifile, "SEQ local_command_list = local_command*")
     call ifile_append (ifile, "ALT local_command = " &
          // "cmd_model | cmd_library | cmd_iterations | cmd_sample_format | " &
          // "cmd_var | cmd_slha | " &
          // "cmd_show | " &
          // "cmd_expect | " &
          // "cmd_cuts | cmd_scale | cmd_fac_scale | cmd_ren_scale | " &
          // "cmd_weight | cmd_selection | cmd_reweight | " &
          // "cmd_beams | cmd_beams_pol_density | cmd_beams_pol_fraction | " &
          // "cmd_beams_momentum | cmd_beams_theta | cmd_beams_phi | " &
          // "cmd_observable | cmd_histogram | cmd_plot | cmd_graph | " &
          // "cmd_clear | cmd_record | " &
          // "cmd_analysis | cmd_alt_setup | " &
          // "cmd_open_out | cmd_close_out | cmd_printf | " &
          // "cmd_write_analysis | cmd_compile_analysis | cmd_nlo | cmd_components")
     call ifile_append (ifile, "SEQ cmd_model = model '=' model_name model_arg?")
     call ifile_append (ifile, "KEY model")
     call ifile_append (ifile, "ALT model_name = model_id | string_literal")
     call ifile_append (ifile, "IDE model_id")
     call ifile_append (ifile, "ARG model_arg = ( model_scheme? )")
     call ifile_append (ifile, "ALT model_scheme = " &
          // "ufo_spec | scheme_id | string_literal")
     call ifile_append (ifile, "SEQ ufo_spec = ufo ufo_arg?")
     call ifile_append (ifile, "KEY ufo")
     call ifile_append (ifile, "ARG ufo_arg = ( string_literal )")
     call ifile_append (ifile, "IDE scheme_id")
     call ifile_append (ifile, "SEQ cmd_library = library '=' lib_name")
     call ifile_append (ifile, "KEY library")
     call ifile_append (ifile, "ALT lib_name = lib_id | string_literal")
     call ifile_append (ifile, "IDE lib_id")
     call ifile_append (ifile, "ALT cmd_var = " &
          // "cmd_log_decl | cmd_log | " &
          // "cmd_int | cmd_real | cmd_complex | cmd_num | " &
          // "cmd_string_decl | cmd_string | cmd_alias | " &
          // "cmd_result")
     call ifile_append (ifile, "SEQ cmd_log_decl = logical cmd_log")
     call ifile_append (ifile, "SEQ cmd_log = '?' var_name '=' lexpr")
     call ifile_append (ifile, "SEQ cmd_int = int var_name '=' expr")
     call ifile_append (ifile, "SEQ cmd_real = real var_name '=' expr")
     call ifile_append (ifile, "SEQ cmd_complex = complex var_name '=' expr")
     call ifile_append (ifile, "SEQ cmd_num = var_name '=' expr")
     call ifile_append (ifile, "SEQ cmd_string_decl = string cmd_string")
     call ifile_append (ifile, "SEQ cmd_string = " &
          // "'$' var_name '=' sexpr") ! $
     call ifile_append (ifile, "SEQ cmd_alias = alias var_name '=' cexpr")
     call ifile_append (ifile, "SEQ cmd_result = result '=' expr")
     call ifile_append (ifile, "SEQ cmd_slha = slha_action slha_arg options?")
     call ifile_append (ifile, "ALT slha_action = " &
          // "read_slha | write_slha")
     call ifile_append (ifile, "KEY read_slha")
     call ifile_append (ifile, "KEY write_slha")
     call ifile_append (ifile, "ARG slha_arg = ( string_literal )")
     call ifile_append (ifile, "SEQ cmd_show = show show_arg options?")
     call ifile_append (ifile, "KEY show")
     call ifile_append (ifile, "ARG show_arg = ( showable* )")
     call ifile_append (ifile, "ALT showable = " &
          // "model | library | beams | iterations | " &
          // "cuts | weight | logical | string | pdg | " &
          // "scale | factorization_scale | renormalization_scale | " &
    // "selection | reweight | analysis | " &
          // "stable | unstable | polarized | unpolarized | " &
          // "expect | intrinsic | int | real | complex | " &
          // "alias_var | string | results | result_var | " &
          // "log_var | string_var | var_name")
     call ifile_append (ifile, "KEY results")
     call ifile_append (ifile, "KEY intrinsic")
     call ifile_append (ifile, "SEQ alias_var = alias var_name")
     call ifile_append (ifile, "SEQ result_var = result_key result_arg?")
     call ifile_append (ifile, "SEQ log_var = '?' var_name")
     call ifile_append (ifile, "SEQ string_var = '$' var_name")  ! $
     call ifile_append (ifile, "SEQ cmd_clear = clear clear_arg options?")
     call ifile_append (ifile, "KEY clear")
     call ifile_append (ifile, "ARG clear_arg = ( clearable* )")
     call ifile_append (ifile, "ALT clearable = " &
          // "beams | iterations | " &
          // "cuts | weight | " &
          // "scale | factorization_scale | renormalization_scale | " &
    // "selection | reweight | analysis | " &
          // "unstable | polarized | " &
          // "expect | " &
          // "log_var | string_var | var_name")
     call ifile_append (ifile, "SEQ cmd_expect = expect expect_arg options?")
     call ifile_append (ifile, "KEY expect")
     call ifile_append (ifile, "ARG expect_arg = ( lexpr )")
     call ifile_append (ifile, "SEQ cmd_cuts = cuts '=' lexpr")
     call ifile_append (ifile, "SEQ cmd_scale = scale '=' expr")
     call ifile_append (ifile, "SEQ cmd_fac_scale = " &
          // "factorization_scale '=' expr")
     call ifile_append (ifile, "SEQ cmd_ren_scale = " &
          // "renormalization_scale '=' expr")
     call ifile_append (ifile, "SEQ cmd_weight = weight '=' expr")
     call ifile_append (ifile, "SEQ cmd_selection = selection '=' lexpr")
     call ifile_append (ifile, "SEQ cmd_reweight = reweight '=' expr")
     call ifile_append (ifile, "KEY cuts")
     call ifile_append (ifile, "KEY scale")
     call ifile_append (ifile, "KEY factorization_scale")
     call ifile_append (ifile, "KEY renormalization_scale")
     call ifile_append (ifile, "KEY weight")
     call ifile_append (ifile, "KEY selection")
     call ifile_append (ifile, "KEY reweight")
     call ifile_append (ifile, "SEQ cmd_process = process process_id '=' " &
          // "process_prt '=>' prt_state_list options?")
     call ifile_append (ifile, "KEY process")
     call ifile_append (ifile, "KEY '=>'")
     call ifile_append (ifile, "LIS process_prt = cexpr+")
     call ifile_append (ifile, "LIS prt_state_list = prt_state_sum+")
     call ifile_append (ifile, "SEQ prt_state_sum = " &
          // "prt_state prt_state_addition*")
     call ifile_append (ifile, "SEQ prt_state_addition = '+' prt_state")
     call ifile_append (ifile, "ALT prt_state = grouped_prt_state_list | cexpr")
     call ifile_append (ifile, "GRO grouped_prt_state_list = " &
          // "( prt_state_list )")
     call ifile_append (ifile, "SEQ cmd_compile = compile_cmd options?")
     call ifile_append (ifile, "SEQ compile_cmd = compile_clause compile_arg?")
     call ifile_append (ifile, "SEQ compile_clause = compile exec_name_spec?")
     call ifile_append (ifile, "KEY compile")
     call ifile_append (ifile, "SEQ exec_name_spec = as exec_name")
     call ifile_append (ifile, "KEY as")
     call ifile_append (ifile, "ALT exec_name = exec_id | string_literal")
     call ifile_append (ifile, "IDE exec_id")
     call ifile_append (ifile, "ARG compile_arg = ( lib_name* )")
     call ifile_append (ifile, "SEQ cmd_exec = exec exec_arg")
     call ifile_append (ifile, "KEY exec")
     call ifile_append (ifile, "ARG exec_arg = ( sexpr )")
     call ifile_append (ifile, "SEQ cmd_beams = beams '=' beam_def")
     call ifile_append (ifile, "KEY beams")
     call ifile_append (ifile, "SEQ beam_def = beam_spec strfun_seq*")
     call ifile_append (ifile, "SEQ beam_spec = beam_list")
     call ifile_append (ifile, "LIS beam_list = cexpr, cexpr?")
     call ifile_append (ifile, "SEQ cmd_beams_pol_density = " &
          // "beams_pol_density '=' beams_pol_spec")
     call ifile_append (ifile, "KEY beams_pol_density")
     call ifile_append (ifile, "LIS beams_pol_spec = smatrix, smatrix?")
     call ifile_append (ifile, "SEQ smatrix = '@' smatrix_arg")
     ! call ifile_append (ifile, "KEY '@'")     !!! Key already exists
     call ifile_append (ifile, "ARG smatrix_arg = ( sentry* )")
     call ifile_append (ifile, "SEQ sentry = expr extra_sentry*")
     call ifile_append (ifile, "SEQ extra_sentry = ':' expr")
     call ifile_append (ifile, "SEQ cmd_beams_pol_fraction = " &
          // "beams_pol_fraction '=' beams_par_spec")
     call ifile_append (ifile, "KEY beams_pol_fraction")
     call ifile_append (ifile, "SEQ cmd_beams_momentum = " &
          // "beams_momentum '=' beams_par_spec")
     call ifile_append (ifile, "KEY beams_momentum")
     call ifile_append (ifile, "SEQ cmd_beams_theta = " &
          // "beams_theta '=' beams_par_spec")
     call ifile_append (ifile, "KEY beams_theta")
     call ifile_append (ifile, "SEQ cmd_beams_phi = " &
          // "beams_phi '=' beams_par_spec")
     call ifile_append (ifile, "KEY beams_phi")
     call ifile_append (ifile, "LIS beams_par_spec = expr, expr?")
     call ifile_append (ifile, "SEQ strfun_seq = '=>' strfun_pair")
     call ifile_append (ifile, "LIS strfun_pair = strfun_def, strfun_def?")
     call ifile_append (ifile, "SEQ strfun_def = strfun_id")
     call ifile_append (ifile, "ALT strfun_id = " &
           // "none | lhapdf | lhapdf_photon | pdf_builtin | pdf_builtin_photon | " &
           // "isr | epa | ewa | circe1 | circe2 | energy_scan | " &
           // "gaussian | beam_events")
     call ifile_append (ifile, "KEY none")
     call ifile_append (ifile, "KEY lhapdf")
     call ifile_append (ifile, "KEY lhapdf_photon")
     call ifile_append (ifile, "KEY pdf_builtin")
     call ifile_append (ifile, "KEY pdf_builtin_photon")
     call ifile_append (ifile, "KEY isr")
     call ifile_append (ifile, "KEY epa")
     call ifile_append (ifile, "KEY ewa")
     call ifile_append (ifile, "KEY circe1")
     call ifile_append (ifile, "KEY circe2")
     call ifile_append (ifile, "KEY energy_scan")
     call ifile_append (ifile, "KEY gaussian")
     call ifile_append (ifile, "KEY beam_events")
     call ifile_append (ifile, "SEQ cmd_integrate = " &
          // "integrate proc_arg options?")
     call ifile_append (ifile, "KEY integrate")
     call ifile_append (ifile, "ARG proc_arg = ( proc_id* )")
     call ifile_append (ifile, "IDE proc_id")
     call ifile_append (ifile, "SEQ cmd_iterations = " &
          // "iterations '=' iterations_list")
     call ifile_append (ifile, "KEY iterations")
     call ifile_append (ifile, "LIS iterations_list = iterations_spec+")
     call ifile_append (ifile, "ALT iterations_spec = it_spec")
     call ifile_append (ifile, "SEQ it_spec = expr calls_spec adapt_spec?")
     call ifile_append (ifile, "SEQ calls_spec = ':' expr")
     call ifile_append (ifile, "SEQ adapt_spec = ':' sexpr")
     call ifile_append (ifile, "SEQ cmd_components = " &
          // "active '=' component_list")
     call ifile_append (ifile, "KEY active")
     call ifile_append (ifile, "LIS component_list = sexpr+")
     call ifile_append (ifile, "SEQ cmd_sample_format = " &
          // "sample_format '=' event_format_list")
     call ifile_append (ifile, "KEY sample_format")
     call ifile_append (ifile, "LIS event_format_list = event_format+")
     call ifile_append (ifile, "IDE event_format")
     call ifile_append (ifile, "SEQ cmd_observable = " &
          // "observable analysis_tag options?")
     call ifile_append (ifile, "KEY observable")
     call ifile_append (ifile, "SEQ cmd_histogram = " &
          // "histogram analysis_tag histogram_arg " &
          // "options?")
     call ifile_append (ifile, "KEY histogram")
     call ifile_append (ifile, "ARG histogram_arg = (expr, expr, expr?)")
     call ifile_append (ifile, "SEQ cmd_plot = plot analysis_tag options?")
     call ifile_append (ifile, "KEY plot")
     call ifile_append (ifile, "SEQ cmd_graph = graph graph_term '=' graph_def")
     call ifile_append (ifile, "KEY graph")
     call ifile_append (ifile, "SEQ graph_term = analysis_tag options?")
     call ifile_append (ifile, "SEQ graph_def = graph_term graph_append*")
     call ifile_append (ifile, "SEQ graph_append = '&' graph_term")
     call ifile_append (ifile, "SEQ cmd_analysis = analysis '=' lexpr")
     call ifile_append (ifile, "KEY analysis")
     call ifile_append (ifile, "SEQ cmd_alt_setup = " &
          // "alt_setup '=' option_list_expr")
     call ifile_append (ifile, "KEY alt_setup")
     call ifile_append (ifile, "ALT option_list_expr = " &
          // "grouped_option_list | option_list")
     call ifile_append (ifile, "GRO grouped_option_list = ( option_list_expr )")
     call ifile_append (ifile, "LIS option_list = options+")
     call ifile_append (ifile, "SEQ cmd_open_out = open_out open_arg options?")
     call ifile_append (ifile, "SEQ cmd_close_out = close_out open_arg options?")
     call ifile_append (ifile, "KEY open_out")
     call ifile_append (ifile, "KEY close_out")
     call ifile_append (ifile, "ARG open_arg = (sexpr)")
     call ifile_append (ifile, "SEQ cmd_printf = printf_cmd options?")
     call ifile_append (ifile, "SEQ printf_cmd = printf_clause sprintf_args?")
     call ifile_append (ifile, "SEQ printf_clause = printf sexpr")
     call ifile_append (ifile, "KEY printf")
     call ifile_append (ifile, "SEQ cmd_record = record_cmd")
     call ifile_append (ifile, "SEQ cmd_unstable = " &
          // "unstable cexpr unstable_arg options?")
     call ifile_append (ifile, "KEY unstable")
     call ifile_append (ifile, "ARG unstable_arg = ( proc_id* )")
     call ifile_append (ifile, "SEQ cmd_stable = stable stable_list options?")
     call ifile_append (ifile, "KEY stable")
     call ifile_append (ifile, "LIS stable_list = cexpr+")
     call ifile_append (ifile, "KEY polarized")
     call ifile_append (ifile, "SEQ cmd_polarized = polarized polarized_list options?")
     call ifile_append (ifile, "LIS polarized_list = cexpr+")
     call ifile_append (ifile, "KEY unpolarized")
     call ifile_append (ifile, "SEQ cmd_unpolarized = unpolarized unpolarized_list options?")
     call ifile_append (ifile, "LIS unpolarized_list = cexpr+")
     call ifile_append (ifile, "SEQ cmd_simulate = " &
          // "simulate proc_arg options?")
     call ifile_append (ifile, "KEY simulate")
     call ifile_append (ifile, "SEQ cmd_rescan = " &
          // "rescan sexpr proc_arg options?")
     call ifile_append (ifile, "KEY rescan")
     call ifile_append (ifile, "SEQ cmd_scan = scan scan_var scan_body?")
     call ifile_append (ifile, "KEY scan")
     call ifile_append (ifile, "ALT scan_var = " &
          // "scan_log_decl | scan_log | " &
          // "scan_int | scan_real | scan_complex | scan_num | " &
          // "scan_string_decl | scan_string | scan_alias | " &
          // "scan_cuts | scan_weight | " &
          // "scan_scale | scan_ren_scale | scan_fac_scale | " &
          // "scan_selection | scan_reweight | scan_analysis | " &
          // "scan_model | scan_library")
     call ifile_append (ifile, "SEQ scan_log_decl = logical scan_log")
     call ifile_append (ifile, "SEQ scan_log = '?' var_name '=' scan_log_arg")
     call ifile_append (ifile, "ARG scan_log_arg = ( lexpr* )")
     call ifile_append (ifile, "SEQ scan_int = int var_name '=' scan_num_arg")
     call ifile_append (ifile, "SEQ scan_real = real var_name '=' scan_num_arg")
     call ifile_append (ifile, "SEQ scan_complex = " &
          // "complex var_name '=' scan_num_arg")
     call ifile_append (ifile, "SEQ scan_num = var_name '=' scan_num_arg")
     call ifile_append (ifile, "ARG scan_num_arg = ( range* )")
     call ifile_append (ifile, "ALT range = grouped_range | range_expr")
     call ifile_append (ifile, "GRO grouped_range = ( range_expr )")
     call ifile_append (ifile, "SEQ range_expr = expr range_spec?")
     call ifile_append (ifile, "SEQ range_spec = '=>' expr step_spec?")
     call ifile_append (ifile, "SEQ step_spec = step_op expr")
     call ifile_append (ifile, "ALT step_op = " &
          // "'/+' | '/-' | '/*' | '//' | '/+/' | '/*/'")
     call ifile_append (ifile, "KEY '/+'")
     call ifile_append (ifile, "KEY '/-'")
     call ifile_append (ifile, "KEY '/*'")
     call ifile_append (ifile, "KEY '//'")
     call ifile_append (ifile, "KEY '/+/'")
     call ifile_append (ifile, "KEY '/*/'")
     call ifile_append (ifile, "SEQ scan_string_decl = string scan_string")
     call ifile_append (ifile, "SEQ scan_string = " &
          // "'$' var_name '=' scan_string_arg")
     call ifile_append (ifile, "ARG scan_string_arg = ( sexpr* )")
     call ifile_append (ifile, "SEQ scan_alias = " &
          // "alias var_name '=' scan_alias_arg")
     call ifile_append (ifile, "ARG scan_alias_arg = ( cexpr* )")
     call ifile_append (ifile, "SEQ scan_cuts = cuts '=' scan_lexpr_arg")
     call ifile_append (ifile, "ARG scan_lexpr_arg = ( lexpr* )")
     call ifile_append (ifile, "SEQ scan_scale = scale '=' scan_expr_arg")
     call ifile_append (ifile, "ARG scan_expr_arg = ( expr* )")
     call ifile_append (ifile, "SEQ scan_fac_scale = " &
          // "factorization_scale '=' scan_expr_arg")
     call ifile_append (ifile, "SEQ scan_ren_scale = " &
          // "renormalization_scale '=' scan_expr_arg")
     call ifile_append (ifile, "SEQ scan_weight = weight '=' scan_expr_arg")
     call ifile_append (ifile, "SEQ scan_selection = selection '=' scan_lexpr_arg")
     call ifile_append (ifile, "SEQ scan_reweight = reweight '=' scan_expr_arg")
     call ifile_append (ifile, "SEQ scan_analysis = analysis '=' scan_lexpr_arg")
     call ifile_append (ifile, "SEQ scan_model = model '=' scan_model_arg")
     call ifile_append (ifile, "ARG scan_model_arg = ( model_name* )")
     call ifile_append (ifile, "SEQ scan_library = library '=' scan_library_arg")
     call ifile_append (ifile, "ARG scan_library_arg = ( lib_name* )")
     call ifile_append (ifile, "GRO scan_body = '{' command_list '}'")
     call ifile_append (ifile, "SEQ cmd_if = " &
          // "if lexpr then command_list elsif_clauses else_clause endif")
     call ifile_append (ifile, "SEQ elsif_clauses = cmd_elsif*")
     call ifile_append (ifile, "SEQ cmd_elsif = elsif lexpr then command_list")
     call ifile_append (ifile, "SEQ else_clause = cmd_else?")
     call ifile_append (ifile, "SEQ cmd_else = else command_list")
     call ifile_append (ifile, "SEQ cmd_include = include include_arg")
     call ifile_append (ifile, "KEY include")
     call ifile_append (ifile, "ARG include_arg = ( string_literal )")
     call ifile_append (ifile, "SEQ cmd_quit = quit_cmd quit_arg?")
     call ifile_append (ifile, "ALT quit_cmd = quit | exit")
     call ifile_append (ifile, "KEY quit")
     call ifile_append (ifile, "KEY exit")
     call ifile_append (ifile, "ARG quit_arg = ( expr )")
     call ifile_append (ifile, "SEQ cmd_export = export show_arg options?")
     call ifile_append (ifile, "KEY export")
     call ifile_append (ifile, "SEQ cmd_write_analysis = " &
          // "write_analysis_clause options?")
     call ifile_append (ifile, "SEQ cmd_compile_analysis = " &
          // "compile_analysis_clause options?")
     call ifile_append (ifile, "SEQ write_analysis_clause = " &
          // "write_analysis write_analysis_arg?")
     call ifile_append (ifile, "SEQ compile_analysis_clause = " &
          // "compile_analysis write_analysis_arg?")
     call ifile_append (ifile, "KEY write_analysis")
     call ifile_append (ifile, "KEY compile_analysis")
     call ifile_append (ifile, "ARG write_analysis_arg = ( analysis_tag* )")
     call ifile_append (ifile, "SEQ cmd_nlo = " &
                        // "nlo_calculation '=' nlo_calculation_list")
     call ifile_append (ifile, "KEY nlo_calculation")
     call ifile_append (ifile, "LIS nlo_calculation_list = nlo_comp+")
     call ifile_append (ifile, "ALT nlo_comp = " // &
          "full | born | real | virtual | dglap | subtraction | " // &
          "mismatch | GKS")
     call ifile_append (ifile, "KEY full")
     call ifile_append (ifile, "KEY born")
     call ifile_append (ifile, "KEY virtual")
     call ifile_append (ifile, "KEY dglap")
     call ifile_append (ifile, "KEY subtraction")
     call ifile_append (ifile, "KEY mismatch")
     call ifile_append (ifile, "KEY GKS")
     call define_expr_syntax (ifile, particles=.true., analysis=.true.)
   end subroutine define_cmd_list_syntax
 
 @ %def define_cmd_list_syntax
 <<Commands: public>>=
   public :: lexer_init_cmd_list
 <<Commands: procedures>>=
   subroutine lexer_init_cmd_list (lexer, parent_lexer)
     type(lexer_t), intent(out) :: lexer
     type(lexer_t), intent(in), optional, target :: parent_lexer
     call lexer_init (lexer, &
          comment_chars = "#!", &
          quote_chars = '"', &
          quote_match = '"', &
          single_chars = "()[]{},;:&%?$@", &
          special_class = [ "+-*/^", "<>=~ " ] , &
          keyword_list = syntax_get_keyword_list_ptr (syntax_cmd_list), &
          parent = parent_lexer)
   end subroutine lexer_init_cmd_list
 
 @ %def lexer_init_cmd_list
 @
 \subsection{Unit Tests}
 Test module, followed by the corresponding implementation module.
 <<[[commands_ut.f90]]>>=
 <<File header>>
 
 module commands_ut
   use unit_tests
   use commands_uti
 
 <<Standard module head>>
 
 <<Commands: public test>>
 
 contains
 
 <<Commands: test driver>>
 
 end module commands_ut
 @ %def commands_ut
 @
 <<[[commands_uti.f90]]>>=
 <<File header>>
 
 module commands_uti
 
   <<Use kinds>>
     use kinds, only: i64
   <<Use strings>>
     use io_units
     use ifiles
     use parser
     use interactions, only: reset_interaction_counter
     use prclib_stacks
     use analysis
     use variables, only: var_list_t
     use models
     use slha_interface
     use rt_data
     use event_base, only: generic_event_t, event_callback_t
 
     use commands
 
 <<Standard module head>>
 
 <<Commands: test declarations>>
 
 <<Commands: test auxiliary types>>
 
 contains
 
 <<Commands: tests>>
 
 <<Commands: test auxiliary>>
 
 end module commands_uti
 
 @ %def commands_uti
 @ API: driver for the unit tests below.
 <<Commands: public test>>=
   public :: commands_test
 <<Commands: test driver>>=
   subroutine commands_test (u, results)
     integer, intent(in) :: u
     type(test_results_t), intent(inout) :: results
   <<Commands: execute tests>>
   end subroutine commands_test
 
 @ %def commands_test
 @
 \subsubsection{Prepare Sindarin code}
 This routine parses an internal file, prints the parse tree, and
 returns a parse node to the root.  We use the routine in the tests
 below.
 <<Commands: public test auxiliary>>=
   public :: parse_ifile
 <<Commands: test auxiliary>>=
   subroutine parse_ifile (ifile, pn_root, u)
     use ifiles
     use lexers
     use parser
     use commands
     type(ifile_t), intent(in) :: ifile
     type(parse_node_t), pointer, intent(out) :: pn_root
     integer, intent(in), optional :: u
     type(stream_t), target :: stream
     type(lexer_t), target :: lexer
     type(parse_tree_t) :: parse_tree
 
     call lexer_init_cmd_list (lexer)
     call stream_init (stream, ifile)
     call lexer_assign_stream (lexer, stream)
 
     call parse_tree_init (parse_tree, syntax_cmd_list, lexer)
     if (present (u))  call parse_tree_write (parse_tree, u)
     pn_root => parse_tree%get_root_ptr ()
 
     call stream_final (stream)
     call lexer_final (lexer)
   end subroutine parse_ifile
 
 @ %def parse_ifile
 @
 \subsubsection{Empty command list}
 Compile and execute an empty command list.  Should do nothing but
 test the integrity of the workflow.
 <<Commands: execute tests>>=
   call test (commands_1, "commands_1", &
        "empty command list", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_1
 <<Commands: tests>>=
   subroutine commands_1 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_1"
     write (u, "(A)")  "*   Purpose: compile and execute empty command list"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Parse empty file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
 
     if (associated (pn_root)) then
        call command_list%compile (pn_root, global)
     end if
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
 
     call global%activate ()
     call command_list%execute (global)
     call global%deactivate ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call syntax_cmd_list_final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_1"
 
   end subroutine commands_1
 
 @ %def commands_1
 @
 \subsubsection{Read model}
 Execute a [[model]] assignment.
 <<Commands: execute tests>>=
   call test (commands_2, "commands_2", &
        "model", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_2
 <<Commands: tests>>=
   subroutine commands_2 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_2"
     write (u, "(A)")  "*   Purpose: set model"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_2"
 
   end subroutine commands_2
 
 @ %def commands_2
 @
 \subsubsection{Declare Process}
 Read a model, then declare a process.  The process library is allocated
 explicitly.  For the process definition, We take the default ([[omega]])
 method.  Since we do not compile, \oMega\ is not actually called.
 <<Commands: execute tests>>=
   call test (commands_3, "commands_3", &
        "process declaration", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_3
 <<Commands: tests>>=
   subroutine commands_3 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
 
     write (u, "(A)")  "* Test output: commands_3"
     write (u, "(A)")  "*   Purpose: define process"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
     call global%var_list%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
 
     allocate (lib)
     call lib%init (var_str ("lib_cmd3"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process t3 = s, s => s, s')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%prclib_stack%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_3"
 
   end subroutine commands_3
 
 @ %def commands_3
 @
 \subsubsection{Compile Process}
 Read a model, then declare a process and compile the library.  The process
 library is allocated explicitly.  For the process definition, We take the
 default ([[unit_test]]) method.  There is no external code, so compilation of
 the library is merely a formal status change.
 <<Commands: execute tests>>=
   call test (commands_4, "commands_4", &
        "compilation", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_4
 <<Commands: tests>>=
   subroutine commands_4 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
 
     write (u, "(A)")  "* Test output: commands_4"
     write (u, "(A)")  "*   Purpose: define process and compile library"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
     call global%var_list%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known=.true.)
 
     allocate (lib)
     call lib%init (var_str ("lib_cmd4"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process t4 = s, s => s, s')
     call ifile_append (ifile, 'compile ("lib_cmd4")')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%prclib_stack%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_4"
 
   end subroutine commands_4
 
 @ %def commands_4
 @
 \subsubsection{Integrate Process}
 Read a model, then declare a process, compile the library, and
 integrate over phase space.  We take the
 default ([[unit_test]]) method and use the simplest methods of
 phase-space parameterization and integration.
 <<Commands: execute tests>>=
   call test (commands_5, "commands_5", &
        "integration", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_5
 <<Commands: tests>>=
   subroutine commands_5 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
 
     write (u, "(A)")  "* Test output: commands_5"
     write (u, "(A)")  "*   Purpose: define process, iterations, and integrate"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
     call global%var_list%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known=.true.)
     call global%var_list%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known=.true.)
     call global%var_list%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known=.true.)
     call global%var_list%set_log (var_str ("?vis_history"),&
          .false., is_known=.true.)
     call global%var_list%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%var_list%set_real (var_str ("sqrts"), &
          1000._default, is_known=.true.)
     call global%var_list%set_int (var_str ("seed"), 0, is_known=.true.)
 
     allocate (lib)
     call lib%init (var_str ("lib_cmd5"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process t5 = s, s => s, s')
     call ifile_append (ifile, 'compile')
     call ifile_append (ifile, 'iterations = 1:1000')
     call ifile_append (ifile, 'integrate (t5)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call reset_interaction_counter ()
     call command_list%execute (global)
 
     call global%it_list%write (u)
     write (u, "(A)")
     call global%process_stack%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_5"
 
   end subroutine commands_5
 
 @ %def commands_5
 @
 \subsubsection{Variables}
 Set intrinsic and user-defined variables.
 <<Commands: execute tests>>=
   call test (commands_6, "commands_6", &
        "variables", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_6
 <<Commands: tests>>=
   subroutine commands_6 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_6"
     write (u, "(A)")  "*   Purpose: define and set variables"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
     call global%write_vars (u, [ &
          var_str ("$run_id"), &
          var_str ("?unweighted"), &
          var_str ("sqrts")])
 
     write (u, "(A)")
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, '$run_id = "run1"')
     call ifile_append (ifile, '?unweighted = false')
     call ifile_append (ifile, 'sqrts = 1000')
     call ifile_append (ifile, 'int j = 10')
     call ifile_append (ifile, 'real x = 1000.')
     call ifile_append (ifile, 'complex z = 5')
     call ifile_append (ifile, 'string $text = "abcd"')
     call ifile_append (ifile, 'logical ?flag = true')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write_vars (u, [ &
          var_str ("$run_id"), &
          var_str ("?unweighted"), &
          var_str ("sqrts"), &
          var_str ("j"), &
          var_str ("x"), &
          var_str ("z"), &
          var_str ("$text"), &
          var_str ("?flag")])
 
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call syntax_cmd_list_final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_6"
 
   end subroutine commands_6
 
 @ %def commands_6
 @
 \subsubsection{Process library}
 Open process libraries explicitly.
 <<Commands: execute tests>>=
   call test (commands_7, "commands_7", &
        "process library", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_7
 <<Commands: tests>>=
   subroutine commands_7 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_7"
     write (u, "(A)")  "*   Purpose: declare process libraries"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
     call global%var_list%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
     global%os_data%fc = "Fortran-compiler"
     global%os_data%fcflags = "Fortran-flags"
 
     write (u, "(A)")
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'library = "lib_cmd7_1"')
     call ifile_append (ifile, 'library = "lib_cmd7_2"')
     call ifile_append (ifile, 'library = "lib_cmd7_1"')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write_libraries (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call syntax_cmd_list_final ()
     call global%final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_7"
 
   end subroutine commands_7
 
 @ %def commands_7
 @
 \subsubsection{Generate events}
 Read a model, then declare a process, compile the library, and
 generate weighted events.  We take the
 default ([[unit_test]]) method and use the simplest methods of
 phase-space parameterization and integration.
 <<Commands: execute tests>>=
   call test (commands_8, "commands_8", &
        "event generation", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_8
 <<Commands: tests>>=
   subroutine commands_8 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
 
     write (u, "(A)")  "* Test output: commands_8"
     write (u, "(A)")  "*   Purpose: define process, integrate, generate events"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call global%var_list%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known=.true.)
     call global%var_list%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known=.true.)
     call global%var_list%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known=.true.)
     call global%var_list%set_log (var_str ("?vis_history"),&
          .false., is_known=.true.)
     call global%var_list%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%var_list%set_real (var_str ("sqrts"), &
          1000._default, is_known=.true.)
 
     allocate (lib)
     call lib%init (var_str ("lib_cmd8"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process commands_8_p = s, s => s, s')
     call ifile_append (ifile, 'compile')
     call ifile_append (ifile, 'iterations = 1:1000')
     call ifile_append (ifile, 'integrate (commands_8_p)')
     call ifile_append (ifile, '?unweighted = false')
     call ifile_append (ifile, 'n_events = 3')
     call ifile_append (ifile, '?read_raw = false')
     call ifile_append (ifile, 'simulate (commands_8_p)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
 
     call command_list%execute (global)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_8"
 
   end subroutine commands_8
 
 @ %def commands_8
 @
 \subsubsection{Define cuts}
 Declare a cut expression.
 <<Commands: execute tests>>=
   call test (commands_9, "commands_9", &
        "cuts", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_9
 <<Commands: tests>>=
   subroutine commands_9 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(string_t), dimension(0) :: no_vars
 
     write (u, "(A)")  "* Test output: commands_9"
     write (u, "(A)")  "*   Purpose: define cuts"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'cuts = all Pt > 0 [particle]')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write (u, vars = no_vars)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_9"
 
   end subroutine commands_9
 
 @ %def commands_9
 @
 \subsubsection{Beams}
 Define beam setup.
 <<Commands: execute tests>>=
   call test (commands_10, "commands_10", &
        "beams", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_10
 <<Commands: tests>>=
   subroutine commands_10 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_10"
     write (u, "(A)")  "*   Purpose: define beams"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = QCD')
     call ifile_append (ifile, 'sqrts = 1000')
     call ifile_append (ifile, 'beams = p, p')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write_beams (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_10"
 
   end subroutine commands_10
 
 @ %def commands_10
 @
 \subsubsection{Structure functions}
 Define beam setup with structure functions
 <<Commands: execute tests>>=
   call test (commands_11, "commands_11", &
        "structure functions", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_11
 <<Commands: tests>>=
   subroutine commands_11 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_11"
     write (u, "(A)")  "*   Purpose: define beams with structure functions"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = QCD')
     call ifile_append (ifile, 'sqrts = 1100')
     call ifile_append (ifile, 'beams = p, p => lhapdf => pdf_builtin, isr')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write_beams (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_11"
 
   end subroutine commands_11
 
 @ %def commands_11
 @
 \subsubsection{Rescan events}
 Read a model, then declare a process, compile the library, and
 generate weighted events.  We take the
 default ([[unit_test]]) method and use the simplest methods of
 phase-space parameterization and integration.  Then, rescan the
 generated event sample.
 <<Commands: execute tests>>=
   call test (commands_12, "commands_12", &
        "event rescanning", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_12
 <<Commands: tests>>=
   subroutine commands_12 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
 
     write (u, "(A)")  "* Test output: commands_12"
     write (u, "(A)")  "*   Purpose: generate events and rescan"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
 
     call global%global_init ()
     call global%var_list%append_log (&
          var_str ("?rebuild_phase_space"), .false., &
          intrinsic=.true.)
     call global%var_list%append_log (&
          var_str ("?rebuild_grids"), .false., &
          intrinsic=.true.)
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call global%var_list%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known=.true.)
     call global%var_list%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known=.true.)
     call global%var_list%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known=.true.)
     call global%var_list%set_log (var_str ("?vis_history"),&
          .false., is_known=.true.)
     call global%var_list%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%var_list%set_real (var_str ("sqrts"), &
          1000._default, is_known=.true.)
 
     allocate (lib)
     call lib%init (var_str ("lib_cmd12"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process commands_12_p = s, s => s, s')
     call ifile_append (ifile, 'compile')
     call ifile_append (ifile, 'iterations = 1:1000')
     call ifile_append (ifile, 'integrate (commands_12_p)')
     call ifile_append (ifile, '?unweighted = false')
     call ifile_append (ifile, 'n_events = 3')
     call ifile_append (ifile, '?read_raw = false')
     call ifile_append (ifile, 'simulate (commands_12_p)')
     call ifile_append (ifile, '?write_raw = false')
     call ifile_append (ifile, 'rescan "commands_12_p" (commands_12_p)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
 
     call command_list%execute (global)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_12"
 
   end subroutine commands_12
 
 @ %def commands_12
 @
 \subsubsection{Event Files}
 Set output formats for event files.
 <<Commands: execute tests>>=
   call test (commands_13, "commands_13", &
        "event output formats", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_13
 <<Commands: tests>>=
   subroutine commands_13 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
     logical :: exist
 
     write (u, "(A)")  "* Test output: commands_13"
     write (u, "(A)")  "*   Purpose: generate events and rescan"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call global%var_list%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known=.true.)
     call global%var_list%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known=.true.)
     call global%var_list%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known=.true.)
     call global%var_list%set_real (var_str ("sqrts"), &
          1000._default, is_known=.true.)
     call global%var_list%set_log (var_str ("?vis_history"),&
          .false., is_known=.true.)
     call global%var_list%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
 
     allocate (lib)
     call lib%init (var_str ("lib_cmd13"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process commands_13_p = s, s => s, s')
     call ifile_append (ifile, 'compile')
     call ifile_append (ifile, 'iterations = 1:1000')
     call ifile_append (ifile, 'integrate (commands_13_p)')
     call ifile_append (ifile, '?unweighted = false')
     call ifile_append (ifile, 'n_events = 1')
     call ifile_append (ifile, '?read_raw = false')
     call ifile_append (ifile, 'sample_format = weight_stream')
     call ifile_append (ifile, 'simulate (commands_13_p)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
 
     call command_list%execute (global)
 
     write (u, "(A)")
     write (u, "(A)")  "* Verify output files"
     write (u, "(A)")
 
     inquire (file = "commands_13_p.evx", exist = exist)
     if (exist)  write (u, "(1x,A)")  "raw"
 
     inquire (file = "commands_13_p.weights.dat", exist = exist)
     if (exist)  write (u, "(1x,A)")  "weight_stream"
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_13"
 
   end subroutine commands_13
 
 @ %def commands_13
 @
 \subsubsection{Compile Empty Libraries}
 (This is a regression test:)  Declare two empty libraries and compile them.
 <<Commands: execute tests>>=
   call test (commands_14, "commands_14", &
        "empty libraries", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_14
 <<Commands: tests>>=
   subroutine commands_14 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_14"
     write (u, "(A)")  "*   Purpose: define and compile empty libraries"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_cmd_list_init ()
 
     call global%global_init ()
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'library = "lib1"')
     call ifile_append (ifile, 'library = "lib2"')
     call ifile_append (ifile, 'compile ()')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%prclib_stack%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
 
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_14"
 
   end subroutine commands_14
 
 @ %def commands_14
 @
 \subsubsection{Compile Process}
 Read a model, then declare a process and compile the library.  The process
 library is allocated explicitly.  For the process definition, We take the
 default ([[unit_test]]) method.  There is no external code, so compilation of
 the library is merely a formal status change.
 <<Commands: execute tests>>=
   call test (commands_15, "commands_15", &
        "compilation", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_15
 <<Commands: tests>>=
   subroutine commands_15 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
 
     write (u, "(A)")  "* Test output: commands_15"
     write (u, "(A)")  "*   Purpose: define process and compile library"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
     call global%var_list%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known=.true.)
     call global%var_list%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known=.true.)
     call global%var_list%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known=.true.)
     call global%var_list%set_real (var_str ("sqrts"), &
          1000._default, is_known=.true.)
     call global%var_list%set_log (var_str ("?vis_history"),&
          .false., is_known=.true.)
     call global%var_list%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
 
     allocate (lib)
     call lib%init (var_str ("lib_cmd15"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process t15 = s, s => s, s')
     call ifile_append (ifile, 'iterations = 1:1000')
     call ifile_append (ifile, 'integrate (t15)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%prclib_stack%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_15"
 
   end subroutine commands_15
 
 @ %def commands_15
 @
 \subsubsection{Observable}
 Declare an observable, fill it and display.
 <<Commands: execute tests>>=
   call test (commands_16, "commands_16", &
        "observables", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_16
 <<Commands: tests>>=
   subroutine commands_16 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_16"
     write (u, "(A)")  "*   Purpose: declare an observable"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, '$obs_label = "foo"')
     call ifile_append (ifile, '$obs_unit = "cm"')
     call ifile_append (ifile, '$title = "Observable foo"')
     call ifile_append (ifile, '$description = "This is observable foo"')
     call ifile_append (ifile, 'observable foo')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Record two data items"
     write (u, "(A)")
 
     call analysis_record_data (var_str ("foo"), 1._default)
     call analysis_record_data (var_str ("foo"), 3._default)
 
     write (u, "(A)")  "* Display analysis store"
     write (u, "(A)")
 
     call analysis_write (u, verbose=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_16"
 
   end subroutine commands_16
 
 @ %def commands_16
 @
 \subsubsection{Histogram}
 Declare a histogram, fill it and display.
 <<Commands: execute tests>>=
   call test (commands_17, "commands_17", &
        "histograms", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_17
 <<Commands: tests>>=
   subroutine commands_17 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(string_t), dimension(3) :: name
     integer :: i
 
     write (u, "(A)")  "* Test output: commands_17"
     write (u, "(A)")  "*   Purpose: declare histograms"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, '$obs_label = "foo"')
     call ifile_append (ifile, '$obs_unit = "cm"')
     call ifile_append (ifile, '$title = "Histogram foo"')
     call ifile_append (ifile, '$description = "This is histogram foo"')
     call ifile_append (ifile, 'histogram foo (0,5,1)')
     call ifile_append (ifile, '$title = "Histogram bar"')
     call ifile_append (ifile, '$description = "This is histogram bar"')
     call ifile_append (ifile, 'n_bins = 2')
     call ifile_append (ifile, 'histogram bar (0,5)')
     call ifile_append (ifile, '$title = "Histogram gee"')
     call ifile_append (ifile, '$description = "This is histogram gee"')
     call ifile_append (ifile, '?normalize_bins = true')
     call ifile_append (ifile, 'histogram gee (0,5)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Record two data items"
     write (u, "(A)")
 
     name(1) = "foo"
     name(2) = "bar"
     name(3) = "gee"
 
     do i = 1, 3
        call analysis_record_data (name(i), 0.1_default, &
             weight = 0.25_default)
        call analysis_record_data (name(i), 3.1_default)
        call analysis_record_data (name(i), 4.1_default, &
             excess = 0.5_default)
        call analysis_record_data (name(i), 7.1_default)
     end do
 
     write (u, "(A)")  "* Display analysis store"
     write (u, "(A)")
 
     call analysis_write (u, verbose=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_17"
 
   end subroutine commands_17
 
 @ %def commands_17
 @
 \subsubsection{Plot}
 Declare a plot, fill it and display contents.
 <<Commands: execute tests>>=
   call test (commands_18, "commands_18", &
        "plots", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_18
 <<Commands: tests>>=
   subroutine commands_18 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_18"
     write (u, "(A)")  "*   Purpose: declare a plot"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, '$obs_label = "foo"')
     call ifile_append (ifile, '$obs_unit = "cm"')
     call ifile_append (ifile, '$title = "Plot foo"')
     call ifile_append (ifile, '$description = "This is plot foo"')
     call ifile_append (ifile, '$x_label = "x axis"')
     call ifile_append (ifile, '$y_label = "y axis"')
     call ifile_append (ifile, '?x_log = false')
     call ifile_append (ifile, '?y_log = true')
     call ifile_append (ifile, 'x_min = -1')
     call ifile_append (ifile, 'x_max = 1')
     call ifile_append (ifile, 'y_min = 0.1')
     call ifile_append (ifile, 'y_max = 1000')
     call ifile_append (ifile, 'plot foo')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Record two data items"
     write (u, "(A)")
 
     call analysis_record_data (var_str ("foo"), 0._default, 20._default, &
          xerr = 0.25_default)
     call analysis_record_data (var_str ("foo"), 0.5_default, 0.2_default, &
          yerr = 0.07_default)
     call analysis_record_data (var_str ("foo"), 3._default, 2._default)
 
     write (u, "(A)")  "* Display analysis store"
     write (u, "(A)")
 
     call analysis_write (u, verbose=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_18"
 
   end subroutine commands_18
 
 @ %def commands_18
 @
 \subsubsection{Graph}
 Combine two (empty) plots to a graph.
 <<Commands: execute tests>>=
   call test (commands_19, "commands_19", &
        "graphs", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_19
 <<Commands: tests>>=
   subroutine commands_19 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_19"
     write (u, "(A)")  "*   Purpose: combine two plots to a graph"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'plot a')
     call ifile_append (ifile, 'plot b')
     call ifile_append (ifile, '$title = "Graph foo"')
     call ifile_append (ifile, '$description = "This is graph foo"')
     call ifile_append (ifile, 'graph foo = a & b')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Display analysis object"
     write (u, "(A)")
 
     call analysis_write (var_str ("foo"), u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_19"
 
   end subroutine commands_19
 
 @ %def commands_19
 @
 \subsubsection{Record Data}
 Record data in previously allocated analysis objects.
 <<Commands: execute tests>>=
   call test (commands_20, "commands_20", &
        "record data", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_20
 <<Commands: tests>>=
   subroutine commands_20 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_20"
     write (u, "(A)")  "*   Purpose: record data"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization: create observable, histogram, plot"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     call analysis_init_observable (var_str ("o"))
     call analysis_init_histogram (var_str ("h"), 0._default, 1._default, 3, &
          normalize_bins = .false.)
     call analysis_init_plot (var_str ("p"))
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'record o (1.234)')
     call ifile_append (ifile, 'record h (0.5)')
     call ifile_append (ifile, 'record p (1, 2)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Display analysis object"
     write (u, "(A)")
 
     call analysis_write (u, verbose = .true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_20"
 
   end subroutine commands_20
 
 @ %def commands_20
 @
 \subsubsection{Analysis}
 Declare an analysis expression and use it to fill an observable during
 event generation.
 <<Commands: execute tests>>=
   call test (commands_21, "commands_21", &
        "analysis expression", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_21
 <<Commands: tests>>=
   subroutine commands_21 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
 
     write (u, "(A)")  "* Test output: commands_21"
     write (u, "(A)")  "*   Purpose: create and use analysis expression"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization: create observable"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call global%var_list%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known=.true.)
     call global%var_list%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known=.true.)
     call global%var_list%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known=.true.)
     call global%var_list%set_log (var_str ("?vis_history"),&
          .false., is_known=.true.)
     call global%var_list%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
     call global%var_list%set_real (var_str ("sqrts"), &
          1000._default, is_known=.true.)
 
     allocate (lib)
     call lib%init (var_str ("lib_cmd8"))
     call global%add_prclib (lib)
 
     call analysis_init_observable (var_str ("m"))
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process commands_21_p = s, s => s, s')
     call ifile_append (ifile, 'compile')
     call ifile_append (ifile, 'iterations = 1:100')
     call ifile_append (ifile, 'integrate (commands_21_p)')
     call ifile_append (ifile, '?unweighted = true')
     call ifile_append (ifile, 'n_events = 3')
     call ifile_append (ifile, '?read_raw = false')
     call ifile_append (ifile, 'observable m')
     call ifile_append (ifile, 'analysis = record m (eval M [s])')
     call ifile_append (ifile, 'simulate (commands_21_p)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Display analysis object"
     write (u, "(A)")
 
     call analysis_write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_21"
 
   end subroutine commands_21
 
 @ %def commands_21
 @
 \subsubsection{Write Analysis}
 Write accumulated analysis data to file.
 <<Commands: execute tests>>=
   call test (commands_22, "commands_22", &
        "write analysis", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_22
 <<Commands: tests>>=
   subroutine commands_22 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     integer :: u_file, iostat
     logical :: exist
     character(80) :: buffer
 
     write (u, "(A)")  "* Test output: commands_22"
     write (u, "(A)")  "*   Purpose: write analysis data"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization: create observable"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     call analysis_init_observable (var_str ("m"))
     call analysis_record_data (var_str ("m"), 125._default)
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, '$out_file = "commands_22.dat"')
     call ifile_append (ifile, 'write_analysis')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Display analysis data"
     write (u, "(A)")
 
     inquire (file = "commands_22.dat", exist = exist)
     if (.not. exist) then
        write (u, "(A)")  "ERROR: File commands_22.dat not found"
        return
     end if
 
     u_file = free_unit ()
     open (u_file, file = "commands_22.dat", &
          action = "read", status = "old")
     do
        read (u_file, "(A)", iostat = iostat)  buffer
        if (iostat /= 0)  exit
        write (u, "(A)") trim (buffer)
     end do
     close (u_file)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_22"
 
   end subroutine commands_22
 
 @ %def commands_22
 @
 \subsubsection{Compile Analysis}
 Write accumulated analysis data to file and compile.
 <<Commands: execute tests>>=
   call test (commands_23, "commands_23", &
        "compile analysis", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_23
 <<Commands: tests>>=
   subroutine commands_23 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     integer :: u_file, iostat
     character(256) :: buffer
     logical :: exist
     type(graph_options_t) :: graph_options
 
     write (u, "(A)")  "* Test output: commands_23"
     write (u, "(A)")  "*   Purpose: write and compile analysis data"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization: create and fill histogram"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     call graph_options_init (graph_options)
     call graph_options_set (graph_options, &
          title = var_str ("Histogram for test: commands 23"), &
          description = var_str ("This is a test."), &
          width_mm = 125, height_mm = 85)
     call analysis_init_histogram (var_str ("h"), &
          0._default, 10._default, 2._default, .false., &
          graph_options = graph_options)
     call analysis_record_data (var_str ("h"), 1._default)
     call analysis_record_data (var_str ("h"), 1._default)
     call analysis_record_data (var_str ("h"), 1._default)
     call analysis_record_data (var_str ("h"), 1._default)
     call analysis_record_data (var_str ("h"), 3._default)
     call analysis_record_data (var_str ("h"), 3._default)
     call analysis_record_data (var_str ("h"), 3._default)
     call analysis_record_data (var_str ("h"), 5._default)
     call analysis_record_data (var_str ("h"), 7._default)
     call analysis_record_data (var_str ("h"), 7._default)
     call analysis_record_data (var_str ("h"), 7._default)
     call analysis_record_data (var_str ("h"), 7._default)
     call analysis_record_data (var_str ("h"), 9._default)
     call analysis_record_data (var_str ("h"), 9._default)
     call analysis_record_data (var_str ("h"), 9._default)
     call analysis_record_data (var_str ("h"), 9._default)
     call analysis_record_data (var_str ("h"), 9._default)
     call analysis_record_data (var_str ("h"), 9._default)
     call analysis_record_data (var_str ("h"), 9._default)
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, '$out_file = "commands_23.dat"')
     call ifile_append (ifile, 'compile_analysis')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Delete Postscript output"
     write (u, "(A)")
 
     inquire (file = "commands_23.ps", exist = exist)
     if (exist) then
        u_file = free_unit ()
        open (u_file, file = "commands_23.ps", action = "write", status = "old")
        close (u_file, status = "delete")
     end if
     inquire (file = "commands_23.ps", exist = exist)
     write (u, "(1x,A,L1)")  "Postcript output exists = ", exist
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* TeX file"
     write (u, "(A)")
 
     inquire (file = "commands_23.tex", exist = exist)
     if (.not. exist) then
        write (u, "(A)")  "ERROR: File commands_23.tex not found"
        return
     end if
 
     u_file = free_unit ()
     open (u_file, file = "commands_23.tex", &
          action = "read", status = "old")
     do
        read (u_file, "(A)", iostat = iostat)  buffer
        if (iostat /= 0)  exit
        write (u, "(A)") trim (buffer)
     end do
     close (u_file)
     write (u, *)
 
     inquire (file = "commands_23.ps", exist = exist)
     write (u, "(1x,A,L1)")  "Postcript output exists = ", exist
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_23"
 
   end subroutine commands_23
 
 @ %def commands_23
 @
 \subsubsection{Histogram}
 Declare a histogram, fill it and display.
 <<Commands: execute tests>>=
   call test (commands_24, "commands_24", &
        "drawing options", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_24
 <<Commands: tests>>=
   subroutine commands_24 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_24"
     write (u, "(A)")  "*   Purpose: check graph and drawing options"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, '$title = "Title"')
     call ifile_append (ifile, '$description = "Description"')
     call ifile_append (ifile, '$x_label = "X Label"')
     call ifile_append (ifile, '$y_label = "Y Label"')
     call ifile_append (ifile, 'graph_width_mm = 111')
     call ifile_append (ifile, 'graph_height_mm = 222')
     call ifile_append (ifile, 'x_min = -11')
     call ifile_append (ifile, 'x_max = 22')
     call ifile_append (ifile, 'y_min = -33')
     call ifile_append (ifile, 'y_max = 44')
     call ifile_append (ifile, '$gmlcode_bg = "GML Code BG"')
     call ifile_append (ifile, '$gmlcode_fg = "GML Code FG"')
     call ifile_append (ifile, '$fill_options = "Fill Options"')
     call ifile_append (ifile, '$draw_options = "Draw Options"')
     call ifile_append (ifile, '$err_options = "Error Options"')
     call ifile_append (ifile, '$symbol = "Symbol"')
     call ifile_append (ifile, 'histogram foo (0,1)')
     call ifile_append (ifile, 'plot bar')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Display analysis store"
     write (u, "(A)")
 
     call analysis_write (u, verbose=.true.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_24"
 
   end subroutine commands_24
 
 @ %def commands_24
 @
 \subsubsection{Local Environment}
 Declare a local environment.
 <<Commands: execute tests>>=
   call test (commands_25, "commands_25", &
        "local process environment", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_25
 <<Commands: tests>>=
   subroutine commands_25 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_25"
     write (u, "(A)")  "*   Purpose: declare local environment for process"
     write (u, "(A)")
 
     call syntax_model_file_init ()
     call syntax_cmd_list_init ()
     call global%global_init ()
     call global%var_list%set_log (var_str ("?omega_openmp"), &
          .false., is_known = .true.)
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'library = "commands_25_lib"')
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process commands_25_p1 = g, g => g, g &
          &{ model = "QCD" }')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
     call global%write_libraries (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_25"
 
   end subroutine commands_25
 
 @ %def commands_25
 @
 \subsubsection{Alternative Setups}
 Declare a list of alternative setups.
 <<Commands: execute tests>>=
   call test (commands_26, "commands_26", &
        "alternative setups", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_26
 <<Commands: tests>>=
   subroutine commands_26 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_26"
     write (u, "(A)")  "*   Purpose: declare alternative setups for simulation"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'int i = 0')
     call ifile_append (ifile, 'alt_setup = ({ i = 1 }, { i = 2 })')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write_expr (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_26"
 
   end subroutine commands_26
 
 @ %def commands_26
 @
 \subsubsection{Unstable Particle}
 Define decay processes and declare a particle as unstable.  Also check
 the commands stable, polarized, unpolarized.
 <<Commands: execute tests>>=
   call test (commands_27, "commands_27", &
        "unstable and polarized particles", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_27
 <<Commands: tests>>=
   subroutine commands_27 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
 
     write (u, "(A)")  "* Test output: commands_27"
     write (u, "(A)")  "*   Purpose: modify particle properties"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call global%global_init ()
     call global%var_list%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known=.true.)
     call global%var_list%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known=.true.)
     call global%var_list%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known=.true.)
     call global%var_list%set_log (var_str ("?vis_history"),&
          .false., is_known=.true.)
     call global%var_list%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
 
     allocate (lib)
     call lib%init (var_str ("commands_27_lib"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'ff = 0.4')
     call ifile_append (ifile, 'process d1 = s => f, fbar')
     call ifile_append (ifile, 'unstable s (d1)')
     call ifile_append (ifile, 'polarized f, fbar')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Show model"
     write (u, "(A)")
 
     call global%model%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Extra Input"
     write (u, "(A)")
 
     call ifile_final (ifile)
     call ifile_append (ifile, '?diagonal_decay = true')
     call ifile_append (ifile, 'unstable s (d1)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%final ()
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Show model"
     write (u, "(A)")
 
     call global%model%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Extra Input"
     write (u, "(A)")
 
     call ifile_final (ifile)
     call ifile_append (ifile, '?isotropic_decay = true')
     call ifile_append (ifile, 'unstable s (d1)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%final ()
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Show model"
     write (u, "(A)")
 
     call global%model%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Extra Input"
     write (u, "(A)")
 
     call ifile_final (ifile)
     call ifile_append (ifile, 'stable s')
     call ifile_append (ifile, 'unpolarized f')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%final ()
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Show model"
     write (u, "(A)")
 
     call global%model%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_model_file_init ()
     call syntax_cmd_list_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_27"
 
   end subroutine commands_27
 
 @ %def commands_27
 @
 \subsubsection{Quit the program}
 Quit the program.
 <<Commands: execute tests>>=
   call test (commands_28, "commands_28", &
        "quit", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_28
 <<Commands: tests>>=
   subroutine commands_28 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root1, pn_root2
     type(string_t), dimension(0) :: no_vars
 
     write (u, "(A)")  "* Test output: commands_28"
     write (u, "(A)")  "*   Purpose: quit the program"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Input file: quit without code"
     write (u, "(A)")
 
     call ifile_append (ifile, 'quit')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root1, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root1, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write (u, vars = no_vars)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Input file: quit with code"
     write (u, "(A)")
 
     call ifile_final (ifile)
     call command_list%final ()
     call ifile_append (ifile, 'quit ( 3 + 4 )')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root2, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root2, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write (u, vars = no_vars)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_28"
 
   end subroutine commands_28
 
 @ %def commands_28
 @
 \subsubsection{SLHA interface}
 Testing commands steering the SLHA interface.
 <<Commands: execute tests>>=
   call test (commands_29, "commands_29", &
        "SLHA interface", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_29
 <<Commands: tests>>=
   subroutine commands_29 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(var_list_t), pointer :: model_vars
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_29"
     write (u, "(A)")  "*   Purpose: test SLHA interface"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call syntax_model_file_init ()
     call syntax_slha_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Model MSSM, read SLHA file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "MSSM"')
     call ifile_append (ifile, '?slha_read_decays = true')
     call ifile_append (ifile, 'read_slha ("sps1ap_decays.slha")')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Model MSSM, default values:"
     write (u, "(A)")
 
     call global%model%write (u, verbose = .false., &
          show_vertices = .false., show_particles = .false.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Selected global variables"
     write (u, "(A)")
 
     model_vars => global%model%get_var_list_ptr ()
 
     call model_vars%write_var (var_str ("mch1"), u)
     call model_vars%write_var (var_str ("wch1"), u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")  "* Model MSSM, values from SLHA file"
     write (u, "(A)")
 
     call global%model%write (u, verbose = .false., &
          show_vertices = .false., show_particles = .false.)
 
     write (u, "(A)")
     write (u, "(A)")  "* Selected global variables"
     write (u, "(A)")
 
     model_vars => global%model%get_var_list_ptr ()
 
     call model_vars%write_var (var_str ("mch1"), u)
     call model_vars%write_var (var_str ("wch1"), u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_slha_final ()
     call syntax_model_file_final ()
     call syntax_cmd_list_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_29"
 
   end subroutine commands_29
 
 @ %def commands_29
 @
 \subsubsection{Expressions for scales}
 Declare a scale, factorization scale or factorization scale expression.
 <<Commands: execute tests>>=
   call test (commands_30, "commands_30", &
        "scales", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_30
 <<Commands: tests>>=
   subroutine commands_30 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_30"
     write (u, "(A)")  "*   Purpose: define scales"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'scale = 200 GeV')
     call ifile_append (ifile, &
          'factorization_scale = eval Pt [particle]')
     call ifile_append (ifile, &
          'renormalization_scale = eval E [particle]')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write_expr (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_30"
 
   end subroutine commands_30
 
 @ %def commands_30
 @
 \subsubsection{Weight and reweight expressions}
 Declare an expression for event weights and reweighting.
 <<Commands: execute tests>>=
   call test (commands_31, "commands_31", &
        "event weights/reweighting", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_31
 <<Commands: tests>>=
   subroutine commands_31 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_31"
     write (u, "(A)")  "*   Purpose: define weight/reweight"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'weight = eval Pz [particle]')
     call ifile_append (ifile, 'reweight = eval M2 [particle]')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write_expr (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_31"
 
   end subroutine commands_31
 
 @ %def commands_31
 @
 \subsubsection{Selecting events}
 Declare an expression for selecting events in an analysis.
 <<Commands: execute tests>>=
   call test (commands_32, "commands_32", &
        "event selection", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_32
 <<Commands: tests>>=
   subroutine commands_32 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
 
     write (u, "(A)")  "* Test output: commands_32"
     write (u, "(A)")  "*   Purpose: define selection"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'selection = any PDG == 13 [particle]')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     call global%write_expr (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_32"
 
   end subroutine commands_32
 
 @ %def commands_32
 @
 \subsubsection{Executing shell commands}
 Execute a shell command.
 <<Commands: execute tests>>=
   call test (commands_33, "commands_33", &
        "execute shell command", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_33
 <<Commands: tests>>=
   subroutine commands_33 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     integer :: u_file, iostat
     character(3) :: buffer
 
     write (u, "(A)")  "* Test output: commands_33"
     write (u, "(A)")  "*   Purpose: execute shell command"
     write (u, "(A)")
 
     write (u, "(A)")  "*  Initialization"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     write (u, "(A)")  "*  Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'exec ("echo foo >> bar")')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "*  Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
     u_file = free_unit ()
     open (u_file, file = "bar", &
          action = "read", status = "old")
     do
        read (u_file, "(A)", iostat = iostat)  buffer
        if (iostat /= 0) exit
     end do
     write (u, "(A,A)")  "should be 'foo': ", trim (buffer)
     close (u_file)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_33"
 
   end subroutine commands_33
 
 @ %def commands_33
 @
 \subsubsection{Callback}
 Instead of an explicit write, use the callback feature to write the
 analysis file during event generation.  We generate 4 events and
 arrange that the callback is executed while writing the 3rd event.
 <<Commands: execute tests>>=
   call test (commands_34, "commands_34", &
        "analysis via callback", &
        u, results)
 <<Commands: test declarations>>=
   public :: commands_34
 <<Commands: tests>>=
   subroutine commands_34 (u)
     integer, intent(in) :: u
     type(ifile_t) :: ifile
     type(command_list_t), target :: command_list
     type(rt_data_t), target :: global
     type(parse_node_t), pointer :: pn_root
     type(prclib_entry_t), pointer :: lib
     type(event_callback_34_t) :: event_callback
 
     write (u, "(A)")  "* Test output: commands_34"
     write (u, "(A)")  "*   Purpose: write analysis data"
     write (u, "(A)")
 
     write (u, "(A)")  "* Initialization: create observable"
     write (u, "(A)")
 
     call syntax_cmd_list_init ()
     call global%global_init ()
 
     call syntax_model_file_init ()
     call global%global_init ()
     call global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
 
     call global%var_list%set_string (var_str ("$method"), &
          var_str ("unit_test"), is_known=.true.)
     call global%var_list%set_string (var_str ("$phs_method"), &
          var_str ("single"), is_known=.true.)
     call global%var_list%set_string (var_str ("$integration_method"),&
          var_str ("midpoint"), is_known=.true.)
     call global%var_list%set_real (var_str ("sqrts"), &
          1000._default, is_known=.true.)
     call global%var_list%set_log (var_str ("?vis_history"),&
          .false., is_known=.true.)
     call global%var_list%set_log (var_str ("?integration_timer"),&
          .false., is_known = .true.)
 
     allocate (lib)
     call lib%init (var_str ("lib_cmd34"))
     call global%add_prclib (lib)
 
     write (u, "(A)")  "* Prepare callback for writing analysis to I/O unit"
     write (u, "(A)")
 
     event_callback%u = u
     call global%set_event_callback (event_callback)
 
     write (u, "(A)")  "* Input file"
     write (u, "(A)")
 
     call ifile_append (ifile, 'model = "Test"')
     call ifile_append (ifile, 'process commands_34_p = s, s => s, s')
     call ifile_append (ifile, 'compile')
     call ifile_append (ifile, 'iterations = 1:1000')
     call ifile_append (ifile, 'integrate (commands_34_p)')
     call ifile_append (ifile, 'observable sq')
     call ifile_append (ifile, 'analysis = record sq (sqrts)')
     call ifile_append (ifile, 'n_events = 4')
     call ifile_append (ifile, 'event_callback_interval = 3')
     call ifile_append (ifile, 'simulate (commands_34_p)')
 
     call ifile_write (ifile, u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Parse file"
     write (u, "(A)")
 
     call parse_ifile (ifile, pn_root)
 
     write (u, "(A)")  "* Compile command list"
     write (u, "(A)")
 
     call command_list%compile (pn_root, global)
 
     call command_list%write (u)
 
     write (u, "(A)")
     write (u, "(A)")  "* Execute command list"
     write (u, "(A)")
 
     call command_list%execute (global)
 
     write (u, "(A)")
     write (u, "(A)")  "* Cleanup"
 
     call ifile_final (ifile)
 
     call analysis_final ()
     call command_list%final ()
     call global%final ()
     call syntax_cmd_list_final ()
     call syntax_model_file_final ()
 
     write (u, "(A)")
     write (u, "(A)")  "* Test output end: commands_34"
 
   end subroutine commands_34
 
 @ %def commands_34
 @ For this test, we invent a callback object which simply writes the
 analysis file, using the standard call for this.  Here we rely on the
 fact that the analysis data are stored as a global entity, otherwise
 we would have to access them via the event object.
 <<Commands: test auxiliary types>>=
   type, extends (event_callback_t) :: event_callback_34_t
      private
      integer :: u = 0
    contains
      procedure :: write => event_callback_34_write
      procedure :: proc => event_callback_34
   end type event_callback_34_t
 
 @ %def event_callback_t
 @ The output routine is unused.  The actual callback should write the
 analysis data to the output unit that we have injected into the
 callback object.
 <<Commands: test auxiliary>>=
   subroutine event_callback_34_write (event_callback, unit)
     class(event_callback_34_t), intent(in) :: event_callback
     integer, intent(in), optional :: unit
   end subroutine event_callback_34_write
 
   subroutine event_callback_34 (event_callback, i, event)
     class(event_callback_34_t), intent(in) :: event_callback
     integer(i64), intent(in) :: i
     class(generic_event_t), intent(in) :: event
     call analysis_write (event_callback%u)
   end subroutine event_callback_34
 
 @ %def event_callback_34_write
 @ %def event_callback_34
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Toplevel module WHIZARD}
 <<[[whizard.f90]]>>=
 <<File header>>
 
 module whizard
 
   use io_units
 <<Use strings>>
   use system_defs, only: VERSION_STRING
   use system_defs, only: EOF, BACKSLASH
   use diagnostics
   use os_interface
   use ifiles
   use lexers
   use parser
   use eval_trees
   use models
   use phs_forests
   use prclib_stacks
   use slha_interface
   use blha_config
   use rt_data
   use commands
 
 <<Standard module head>>
 
 <<WHIZARD: public>>
 
 <<WHIZARD: types>>
 
   save
 
 contains
 
 <<WHIZARD: procedures>>
 
 end module whizard
 @ %def whizard
 @
 \subsection{Options}
 Here we introduce a wrapper that holds various user options, so they
 can transparently be passed from the main program to the [[whizard]]
 object.  Most parameters are used for initializing the [[global]]
 state.
 <<WHIZARD: public>>=
   public :: whizard_options_t
 <<WHIZARD: types>>=
   type :: whizard_options_t
      type(string_t) :: job_id
      type(string_t), dimension(:), allocatable :: pack_args
      type(string_t), dimension(:), allocatable :: unpack_args
      type(string_t) :: preload_model
      type(string_t) :: default_lib
      type(string_t) :: preload_libraries
      logical :: rebuild_library = .false.
      logical :: recompile_library = .false.
      logical :: rebuild_user
      logical :: rebuild_phs = .false.
      logical :: rebuild_grids = .false.
      logical :: rebuild_events = .false.
   end type whizard_options_t
 
 @ %def whizard_options_t
 @
 \subsection{Parse tree stack}
 We collect all parse trees that we generate in the [[whizard]] object.  To
 this end, we create a stack of parse trees.  They must not be finalized before
 the [[global]] object is finalized, because items such as a cut definition may
 contain references to the parse tree from which they were generated.
 <<WHIZARD: types>>=
   type, extends (parse_tree_t) :: pt_entry_t
      type(pt_entry_t), pointer :: previous => null ()
   end type pt_entry_t
 
 @ %def pt_entry_t
 @ This is the stack.  Since we always prepend, we just need the [[last]]
 pointer.
 <<WHIZARD: types>>=
   type :: pt_stack_t
      type(pt_entry_t), pointer :: last => null ()
    contains
    <<WHIZARD: pt stack: TBP>>
   end type pt_stack_t
 
 @ %def pt_stack_t
 @ The finalizer is called at the very end.
 <<WHIZARD: pt stack: TBP>>=
   procedure :: final => pt_stack_final
 <<WHIZARD: procedures>>=
   subroutine pt_stack_final (pt_stack)
     class(pt_stack_t), intent(inout) :: pt_stack
     type(pt_entry_t), pointer :: current
     do while (associated (pt_stack%last))
        current => pt_stack%last
        pt_stack%last => current%previous
        call parse_tree_final (current%parse_tree_t)
        deallocate (current)
     end do
   end subroutine pt_stack_final
 
 @ %def pt_stack_final
 @ Create and push a new entry, keeping the previous ones.
 <<WHIZARD: pt stack: TBP>>=
   procedure :: push => pt_stack_push
 <<WHIZARD: procedures>>=
   subroutine pt_stack_push (pt_stack, parse_tree)
     class(pt_stack_t), intent(inout) :: pt_stack
     type(parse_tree_t), intent(out), pointer :: parse_tree
     type(pt_entry_t), pointer :: current
     allocate (current)
     parse_tree => current%parse_tree_t
     current%previous => pt_stack%last
     pt_stack%last => current
   end subroutine pt_stack_push
 
 @ %def pt_stack_push
 @
 \subsection{The [[whizard]] object}
 An object of type [[whizard_t]] is the top-level wrapper for a
 \whizard\ instance.  The object holds various default
 settings and the current state of the generator, the [[global]] object
 of type [[rt_data_t]].  This object contains, for instance, the list
 of variables and the process libraries.
 
 Since components of the [[global]] subobject are frequently used as
 targets, the [[whizard]] object should also consistently carry the
 [[target]] attribute.
 
 The various self-tests do no not use this object.  They initialize
 only specific subsets of the system, according to their needs.
 
 Note: we intend to allow several concurrent instances.  In the current
 implementation, there are still a few obstacles to this: the model
 library and the syntax tables are global variables, and the error
 handling uses global state.  This should be improved.
 <<WHIZARD: public>>=
   public :: whizard_t
 <<WHIZARD: types>>=
   type :: whizard_t
      type(whizard_options_t) :: options
      type(rt_data_t) :: global
      type(pt_stack_t) :: pt_stack
    contains
    <<WHIZARD: whizard: TBP>>
   end type whizard_t
 
 @ %def whizard_t
 @
 \subsection{Initialization and finalization}
 <<WHIZARD: whizard: TBP>>=
   procedure :: init => whizard_init
 <<WHIZARD: procedures>>=
   subroutine whizard_init (whizard, options, paths, logfile)
     class(whizard_t), intent(out), target :: whizard
     type(whizard_options_t), intent(in) :: options
     type(paths_t), intent(in), optional :: paths
     type(string_t), intent(in), optional :: logfile
     call init_syntax_tables ()
     whizard%options = options
     call whizard%global%global_init (paths, logfile)
     call whizard%init_job_id ()
     call whizard%init_rebuild_flags ()
     call whizard%unpack_files ()
     call whizard%preload_model ()
     call whizard%preload_library ()
     call whizard%global%init_fallback_model &
          (var_str ("SM_hadrons"), var_str ("SM_hadrons.mdl"))
   end subroutine whizard_init
 
 @ %def whizard_init
 @ Apart from the global data which have been initialized above, the
 process and model lists need to be finalized.
 <<WHIZARD: whizard: TBP>>=
   procedure :: final => whizard_final
 <<WHIZARD: procedures>>=
   subroutine whizard_final (whizard)
     class(whizard_t), intent(inout), target :: whizard
     call whizard%global%final ()
     call whizard%pt_stack%final ()
     call whizard%pack_files ()
 !!! JRR: WK please check (#529)
     !    call user_code_final ()
     call final_syntax_tables ()
   end subroutine whizard_final
 
 @ %def whizard_final
 @ Set the job ID, if nonempty.  If the ID string is empty, the value remains
 undefined.
 <<WHIZARD: whizard: TBP>>=
   procedure :: init_job_id => whizard_init_job_id
 <<WHIZARD: procedures>>=
   subroutine whizard_init_job_id (whizard)
     class(whizard_t), intent(inout), target :: whizard
     associate (var_list => whizard%global%var_list, options => whizard%options)
       if (options%job_id /= "") then
          call var_list%set_string (var_str ("$job_id"), &
               options%job_id, is_known=.true.)
       end if
     end associate
   end subroutine whizard_init_job_id
   
 @ %def whizard_init_job_id
 @
 Set the rebuild flags.  They can be specified on the command line and
 set the initial value for the associated logical variables.
 <<WHIZARD: whizard: TBP>>=
   procedure :: init_rebuild_flags => whizard_init_rebuild_flags
 <<WHIZARD: procedures>>=
   subroutine whizard_init_rebuild_flags (whizard)
     class(whizard_t), intent(inout), target :: whizard
     associate (var_list => whizard%global%var_list, options => whizard%options)
       call var_list%append_log (var_str ("?rebuild_library"), &
            options%rebuild_library, intrinsic=.true.)
       call var_list%append_log (var_str ("?recompile_library"), &
            options%recompile_library, intrinsic=.true.)
       call var_list%append_log (var_str ("?rebuild_phase_space"), &
            options%rebuild_phs, intrinsic=.true.)
       call var_list%append_log (var_str ("?rebuild_grids"), &
            options%rebuild_grids, intrinsic=.true.)
       call var_list%append_log (var_str ("?powheg_rebuild_grids"), &
            options%rebuild_grids, intrinsic=.true.)
       call var_list%append_log (var_str ("?rebuild_events"), &
            options%rebuild_events, intrinsic=.true.)
     end associate
   end subroutine whizard_init_rebuild_flags
 
 @ %def whizard_init_rebuild_flags
 @
 Pack/unpack files in the working directory, if requested.
 <<WHIZARD: whizard: TBP>>=
   procedure :: pack_files => whizard_pack_files
   procedure :: unpack_files => whizard_unpack_files
 <<WHIZARD: procedures>>=
   subroutine whizard_pack_files (whizard)
     class(whizard_t), intent(in), target :: whizard
     logical :: exist
     integer :: i
     type(string_t) :: file
     if (allocated (whizard%options%pack_args)) then
        do i = 1, size (whizard%options%pack_args)
           file = whizard%options%pack_args(i)
           call msg_message ("Packing file/dir '" // char (file) // "'")
           exist = os_file_exist (file) .or. os_dir_exist (file) 
           if (exist) then
              call os_pack_file (whizard%options%pack_args(i), &
                   whizard%global%os_data)
           else
              call msg_error ("File/dir '" // char (file) // "' not found")
           end if
        end do
     end if
   end subroutine whizard_pack_files
 
   subroutine whizard_unpack_files (whizard)
     class(whizard_t), intent(in), target :: whizard
     logical :: exist
     integer :: i
     type(string_t) :: file
     if (allocated (whizard%options%unpack_args)) then
        do i = 1, size (whizard%options%unpack_args)
           file = whizard%options%unpack_args(i)
           call msg_message ("Unpacking file '" // char (file) // "'")
           exist = os_file_exist (file) 
           if (exist) then
              call os_unpack_file (whizard%options%unpack_args(i), &
                   whizard%global%os_data)
           else
              call msg_error ("File '" // char (file) // "' not found")
           end if
        end do
     end if
   end subroutine whizard_unpack_files
 
 @ %def whizard_pack_files
 @ %def whizard_unpack_files
 @
 This procedure preloads a model, if a model name is given.
 <<WHIZARD: whizard: TBP>>=
   procedure :: preload_model => whizard_preload_model
 <<WHIZARD: procedures>>=
   subroutine whizard_preload_model (whizard)
     class(whizard_t), intent(inout), target :: whizard
     type(string_t) :: model_name
     model_name = whizard%options%preload_model
     if (model_name /= "") then
        call whizard%global%read_model (model_name, whizard%global%preload_model)
        whizard%global%model => whizard%global%preload_model
        if (associated (whizard%global%model)) then
           call whizard%global%model%link_var_list (whizard%global%var_list)
           call msg_message ("Preloaded model: " &
                // char (model_name))
        else
           call msg_fatal ("Preloading model " // char (model_name) &
                // " failed")
        end if
     else
        call msg_message ("No model preloaded")
     end if
   end subroutine whizard_preload_model
 
 @ %def whizard_preload_model
 @
 This procedure preloads a library, if a library name is given.
 
 Note: This version just opens a new library with that name.  It does not load
 (yet) an existing library on file, as previous \whizard\ versions would do.
 <<WHIZARD: whizard: TBP>>=
   procedure :: preload_library => whizard_preload_library
 <<WHIZARD: procedures>>=
   subroutine whizard_preload_library (whizard)
     class(whizard_t), intent(inout), target :: whizard
     type(string_t) :: library_name, libs
     type(string_t), dimension(:), allocatable :: libname_static
     type(prclib_entry_t), pointer :: lib_entry
     integer :: i
     call get_prclib_static (libname_static)
     do i = 1, size (libname_static)
        allocate (lib_entry)
        call lib_entry%init_static (libname_static(i))
        call whizard%global%add_prclib (lib_entry)
     end do
     libs = adjustl (whizard%options%preload_libraries)
     if (libs == "" .and. whizard%options%default_lib /= "") then
           allocate (lib_entry)
           call lib_entry%init (whizard%options%default_lib)
           call whizard%global%add_prclib (lib_entry)
           call msg_message ("Preloaded library: " // &
                char (whizard%options%default_lib))
        end if
     SCAN_LIBS: do while (libs /= "")
        call split (libs, library_name, " ")
        if (library_name /= "") then
           allocate (lib_entry)
           call lib_entry%init (library_name)
           call whizard%global%add_prclib (lib_entry)
           call msg_message ("Preloaded library: " // char (library_name))
        end if
     end do SCAN_LIBS
   end subroutine whizard_preload_library
 
 @ %def whizard_preload_library
 @
 \subsection{Initialization and finalization (old version)}
 These procedures initialize and finalize global variables.  Most of
 them are collected in the [[global]] data record located here, the
 others are syntax tables located in various modules, which do not
 change during program execution.  Furthermore, there is a global model
 list and a global process store, which get filled during program
 execution but are finalized here.
 
 During initialization, we can preload a default model and initialize a
 default library for setting up processes.  The default library is
 loaded if requested by the setup.  Further libraries can be loaded as
 specified by command-line flags.
 @ Initialize/finalize the syntax tables used by WHIZARD:
 <<WHIZARD: public>>=
   public :: init_syntax_tables
   public :: final_syntax_tables
 <<WHIZARD: procedures>>=
   subroutine init_syntax_tables ()
     call syntax_model_file_init ()
     call syntax_phs_forest_init ()
     call syntax_pexpr_init ()
     call syntax_slha_init ()
     call syntax_cmd_list_init ()
   end subroutine init_syntax_tables
 
   subroutine final_syntax_tables ()
     call syntax_model_file_final ()
     call syntax_phs_forest_final ()
     call syntax_pexpr_final ()
     call syntax_slha_final ()
     call syntax_cmd_list_final ()
   end subroutine final_syntax_tables
 
 @ %def init_syntax_tables
 @ %def final_syntax_tables
 @ Write the syntax tables to external files.
 <<WHIZARD: public>>=
   public :: write_syntax_tables
 <<WHIZARD: procedures>>=
   subroutine write_syntax_tables ()
     integer :: unit
     character(*), parameter :: file_model = "whizard.model_file.syntax"
     character(*), parameter :: file_phs = "whizard.phase_space_file.syntax"
     character(*), parameter :: file_pexpr = "whizard.prt_expressions.syntax"
     character(*), parameter :: file_slha = "whizard.slha.syntax"
     character(*), parameter :: file_sindarin = "whizard.sindarin.syntax"
     unit = free_unit ()
     print *, "Writing file '" // file_model // "'"
     open (unit=unit, file=file_model, status="replace", action="write")
     write (unit, "(A)")  VERSION_STRING
     write (unit, "(A)")  "Syntax definition file: " // file_model
     call syntax_model_file_write (unit)
     close (unit)
     print *, "Writing file '" // file_phs // "'"
     open (unit=unit, file=file_phs, status="replace", action="write")
     write (unit, "(A)")  VERSION_STRING
     write (unit, "(A)")  "Syntax definition file: " // file_phs
     call syntax_phs_forest_write (unit)
     close (unit)
     print *, "Writing file '" // file_pexpr // "'"
     open (unit=unit, file=file_pexpr, status="replace", action="write")
     write (unit, "(A)")  VERSION_STRING
     write (unit, "(A)")  "Syntax definition file: " // file_pexpr
     call syntax_pexpr_write (unit)
     close (unit)
     print *, "Writing file '" // file_slha // "'"
     open (unit=unit, file=file_slha, status="replace", action="write")
     write (unit, "(A)")  VERSION_STRING
     write (unit, "(A)")  "Syntax definition file: " // file_slha
     call syntax_slha_write (unit)
     close (unit)
     print *, "Writing file '" // file_sindarin // "'"
     open (unit=unit, file=file_sindarin, status="replace", action="write")
     write (unit, "(A)")  VERSION_STRING
     write (unit, "(A)")  "Syntax definition file: " // file_sindarin
     call syntax_cmd_list_write (unit)
     close (unit)
   end subroutine write_syntax_tables
 
 @ %def write_syntax_tables
 @
 \subsection{Execute command lists}
 Process commands given on the command line, stored as an [[ifile]].  The whole
 input is read, compiled and executed as a whole.
 <<WHIZARD: whizard: TBP>>=
   procedure :: process_ifile => whizard_process_ifile
 <<WHIZARD: procedures>>=
   subroutine whizard_process_ifile (whizard, ifile, quit, quit_code)
     class(whizard_t), intent(inout), target :: whizard
     type(ifile_t), intent(in) :: ifile
     logical, intent(out) :: quit
     integer, intent(out) :: quit_code
     type(lexer_t), target :: lexer
     type(stream_t), target :: stream
     call msg_message ("Reading commands given on the command line")
     call lexer_init_cmd_list (lexer)
     call stream_init (stream, ifile)
     call whizard%process_stream (stream, lexer, quit, quit_code)
     call stream_final (stream)
     call lexer_final (lexer)
   end subroutine whizard_process_ifile
 
 @ %def whizard_process_ifile
 @ Process standard input as a command list.  The whole input is read,
 compiled and executed as a whole.
 <<WHIZARD: whizard: TBP>>=
   procedure :: process_stdin => whizard_process_stdin
 <<WHIZARD: procedures>>=
   subroutine whizard_process_stdin (whizard, quit, quit_code)
     class(whizard_t), intent(inout), target :: whizard
     logical, intent(out) :: quit
     integer, intent(out) :: quit_code
     type(lexer_t), target :: lexer
     type(stream_t), target :: stream
     call msg_message ("Reading commands from standard input")
     call lexer_init_cmd_list (lexer)
     call stream_init (stream, 5)
     call whizard%process_stream (stream, lexer, quit, quit_code)
     call stream_final (stream)
     call lexer_final (lexer)
   end subroutine whizard_process_stdin
 
 @ %def whizard_process_stdin
 @ Process a file as a command list.
 <<WHIZARD: whizard: TBP>>=
   procedure :: process_file => whizard_process_file
 <<WHIZARD: procedures>>=
   subroutine whizard_process_file (whizard, file, quit, quit_code)
     class(whizard_t), intent(inout), target :: whizard
     type(string_t), intent(in) :: file
     logical, intent(out) :: quit
     integer, intent(out) :: quit_code
     type(lexer_t), target :: lexer
     type(stream_t), target :: stream
     logical :: exist
     call msg_message ("Reading commands from file '" // char (file) // "'")
     inquire (file=char(file), exist=exist)
     if (exist) then
        call lexer_init_cmd_list (lexer)
        call stream_init (stream, char (file))
        call whizard%process_stream (stream, lexer, quit, quit_code)
        call stream_final (stream)
        call lexer_final (lexer)
     else
        call msg_error ("File '" // char (file) // "' not found")
     end if
   end subroutine whizard_process_file
 
 @ %def whizard_process_file
 @
 <<WHIZARD: whizard: TBP>>=
   procedure :: process_stream => whizard_process_stream
 <<WHIZARD: procedures>>=
   subroutine whizard_process_stream (whizard, stream, lexer, quit, quit_code)
     class(whizard_t), intent(inout), target :: whizard
     type(stream_t), intent(inout), target :: stream
     type(lexer_t), intent(inout), target :: lexer
     logical, intent(out) :: quit
     integer, intent(out) :: quit_code
     type(parse_tree_t), pointer :: parse_tree
     type(command_list_t), target :: command_list
     call lexer_assign_stream (lexer, stream)
     call whizard%pt_stack%push (parse_tree)
     call parse_tree_init (parse_tree, syntax_cmd_list, lexer)
     if (associated (parse_tree%get_root_ptr ())) then
        whizard%global%lexer => lexer
        call command_list%compile (parse_tree%get_root_ptr (), &
             whizard%global)
     end if
     call whizard%global%activate ()
     call command_list%execute (whizard%global)
     call command_list%final ()
     quit = whizard%global%quit
     quit_code = whizard%global%quit_code
   end subroutine whizard_process_stream
 
 @ %def whizard_process_stream
 @
 \subsection{The WHIZARD shell}
 This procedure implements interactive mode.  One line is processed at
 a time.
 <<WHIZARD: whizard: TBP>>=
   procedure :: shell => whizard_shell
 <<WHIZARD: procedures>>=
   subroutine whizard_shell (whizard, quit_code)
     class(whizard_t), intent(inout), target :: whizard
     integer, intent(out) :: quit_code
     type(lexer_t), target :: lexer
     type(stream_t), target :: stream
     type(string_t) :: prompt1
     type(string_t) :: prompt2
     type(string_t) :: input
     type(string_t) :: extra
     integer :: last
     integer :: iostat
     logical :: mask_tmp
     logical :: quit
     call msg_message ("Launching interactive shell")
     call lexer_init_cmd_list (lexer)
     prompt1 = "whish? "
     prompt2 = "     > "
     COMMAND_LOOP: do
        call put (6, prompt1)
        call get (5, input, iostat=iostat)
        if (iostat > 0 .or. iostat == EOF) exit COMMAND_LOOP
        CONTINUE_INPUT: do
           last = len_trim (input)
           if (extract (input, last, last) /= BACKSLASH)  exit CONTINUE_INPUT
           call put (6, prompt2)
           call get (5, extra, iostat=iostat)
           if (iostat > 0) exit COMMAND_LOOP
           input = replace (input, last, extra)
        end do CONTINUE_INPUT
        call stream_init (stream, input)
        mask_tmp = mask_fatal_errors
        mask_fatal_errors = .true.
        call whizard%process_stream (stream, lexer, quit, quit_code)
        msg_count = 0
        mask_fatal_errors = mask_tmp
        call stream_final (stream)
        if (quit)  exit COMMAND_LOOP
     end do COMMAND_LOOP
     print *
     call lexer_final (lexer)
   end subroutine whizard_shell
 
 @ %def whizard_shell
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Tools for the command line}
 
-We don't intent to be very smart here, but this module provides a few
+We do not intent to be very smart here, but this module provides a few
 small tools that simplify dealing with the command line.
+
+The [[unquote_value]] subroutine handles an option value that begins with a
+single/double quote character.  It swallows extra option strings until it
+finds a value that ends with another quote character.  The returned string
+consists of all argument strings between quotes, concatenated by blanks (with
+a leading blank).  Note that more complex patterns, such as quoted or embedded
+quotes, or multiple blanks, are not accounted for.
 <<[[cmdline_options.f90]]>>=
 <<File header>>
 
 module cmdline_options
 
 <<Use strings>>
   use diagnostics
 
 <<Standard module head>>
 
   public :: init_options
   public :: no_option_value
   public :: get_option_value
 
 <<Main: cmdline arg len declaration>>
 
   abstract interface
      subroutine msg
      end subroutine msg
   end interface
 
   procedure (msg), pointer :: print_usage => null ()
 
 contains
 
   subroutine init_options (usage_msg)
     procedure (msg) :: usage_msg
     print_usage => usage_msg
   end subroutine init_options
 
   subroutine no_option_value (option, value)
     type(string_t), intent(in) :: option, value
     if (value /= "") then
        call msg_error (" Option '" // char (option) // "' should have no value")
     end if
   end subroutine no_option_value
 
   function get_option_value (i, option, value) result (string)
     type(string_t) :: string
     integer, intent(inout) :: i
     type(string_t), intent(in) :: option
     type(string_t), intent(in), optional :: value
     character(CMDLINE_ARG_LEN) :: arg_value
     integer :: arg_len, arg_status
     logical :: has_value
     if (present (value)) then
        has_value = value /= ""
     else
        has_value = .false.
     end if
     if (has_value) then
-       string = value
+       call unquote_value (i, option, value, string)
     else
        i = i + 1
        call get_command_argument (i, arg_value, arg_len, arg_status)
        select case (arg_status)
        case (0)
        case (-1)
           call msg_error (" Option value truncated: '" // arg_value // "'")
        case default
           call print_usage ()
           call msg_fatal (" Option '" // char (option) // "' needs a value")
        end select
        select case (arg_value(1:1))
        case ("-")
           call print_usage ()
           call msg_fatal (" Option '" // char (option) // "' needs a value")
        end select
-       string = trim (arg_value)
+       call unquote_value (i, option, var_str (trim (arg_value)), string)
     end if
   end function get_option_value
 
+  subroutine unquote_value (i, option, value, string)
+    integer, intent(inout) :: i
+    type(string_t), intent(in) :: option
+    type(string_t), intent(in) :: value
+    type(string_t), intent(out) :: string
+    character(1) :: quote
+    character(CMDLINE_ARG_LEN) :: arg_value
+    integer :: arg_len, arg_status
+    quote = extract (value, 1, 1)
+    select case (quote)
+    case ("'", '"')
+       string = ""
+       arg_value = extract (value, 2)
+       arg_len = len_trim (value)
+       APPEND_QUOTED: do
+          if (extract (arg_value, arg_len, arg_len) == quote) then
+             string = string // " " // extract (arg_value, 1, arg_len-1)
+             exit APPEND_QUOTED
+          else
+             string = string // " " // trim (arg_value)
+             i = i + 1
+             call get_command_argument (i, arg_value, arg_len, arg_status)
+             select case (arg_status)
+             case (0)
+             case (-1)
+                call msg_error (" Quoted option value truncated: '" &
+                     // char (string) // "'")
+             case default
+                call print_usage ()
+                call msg_fatal (" Option '" // char (option) &
+                     // "': unterminated quoted value")
+             end select
+          end if
+       end do APPEND_QUOTED
+    case default
+       string = value
+    end select
+  end subroutine unquote_value
+
 end module cmdline_options
 
 @ %def init_options
 @ %def no_option_value
 @ %def get_option_value
 @ %def cmdline_options
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Query Feature Support}
 This module accesses the various optional features (modules) that
 WHIZARD can support and repors on their availability.
 <<[[features.f90]]>>=
 module features
 
   use string_utils, only: lower_case
   use system_dependencies, only: WHIZARD_VERSION
 <<Features: dependencies>>
 
 <<Standard module head>>
 
 <<Features: public>>
 
 contains
 
 <<Features: procedures>>
 
 end module features
 @ %def features
 @
 \subsection{Output}
 <<Features: public>>=
   public :: print_features
 <<Features: procedures>>=
   subroutine print_features ()
     print "(A)", "WHIZARD " // WHIZARD_VERSION
     print "(A)", "Build configuration:"
   <<Features: config>>
     print "(A)", "Optional features available in this build:"
   <<Features: print>>
   end subroutine print_features
 
 @ %def print_features
 @
 \subsection{Query function}
 <<Features: procedures>>=
   subroutine check (feature, recognized, result, help)
     character(*), intent(in) :: feature
     logical, intent(out) :: recognized
     character(*), intent(out) :: result, help
     recognized = .true.
     result = "no"
     select case (lower_case (trim (feature)))
   <<Features: cases>>
     case default
        recognized = .false.
     end select
   end subroutine check
 
 @ %def check
 @ Print this result:
 <<Features: procedures>>=
   subroutine print_check (feature)
     character(*), intent(in) :: feature
     character(16) :: f
     logical :: recognized
     character(10) :: result
     character(48) :: help
     call check (feature, recognized, result, help)
     if (.not. recognized) then
        result = "unknown"
        help = ""
     end if
     f = feature
     print "(2x,A,1x,A,'(',A,')')", f, result, trim (help)
   end subroutine print_check
 
 @ %def print_check
 @
 \subsection{Basic configuration}
 <<Features: config>>=
   call print_check ("precision")
 <<Features: dependencies>>=
   use kinds, only: default
 <<Features: cases>>=
   case ("precision")
      write (result, "(I0)")  precision (1._default)
      help = "significant decimals of real/complex numbers"
 @
 \subsection{Optional features case by case}
 <<Features: print>>=
   call print_check ("OpenMP")
 <<Features: dependencies>>=
   use system_dependencies, only: openmp_is_active
 <<Features: cases>>=
   case ("openmp")
      if (openmp_is_active ()) then
         result = "yes"
      end if
      help = "OpenMP parallel execution"
 @
 <<Features: print>>=
   call print_check ("GoSam")
 <<Features: dependencies>>=
   use system_dependencies, only: GOSAM_AVAILABLE
 <<Features: cases>>=
   case ("gosam")
      if (GOSAM_AVAILABLE) then
         result = "yes"
      end if
      help = "external NLO matrix element provider"
 @
 <<Features: print>>=
   call print_check ("OpenLoops")
 <<Features: dependencies>>=
   use system_dependencies, only: OPENLOOPS_AVAILABLE
 <<Features: cases>>=
   case ("openloops")
      if (OPENLOOPS_AVAILABLE) then
         result = "yes"
      end if
      help = "external NLO matrix element provider"
 @
 <<Features: print>>=
   call print_check ("Recola")
 <<Features: dependencies>>=
   use system_dependencies, only: RECOLA_AVAILABLE
 <<Features: cases>>=
   case ("recola")
      if (RECOLA_AVAILABLE) then
         result = "yes"
      end if
      help = "external NLO matrix element provider"
 @
 <<Features: print>>=
   call print_check ("LHAPDF")
 <<Features: dependencies>>=
   use system_dependencies, only: LHAPDF5_AVAILABLE
   use system_dependencies, only: LHAPDF6_AVAILABLE
 <<Features: cases>>=
   case ("lhapdf")
      if (LHAPDF5_AVAILABLE) then
         result = "v5"
      else if (LHAPDF6_AVAILABLE) then
         result = "v6"
      end if
      help = "PDF library"
 @
 <<Features: print>>=
   call print_check ("HOPPET")
 <<Features: dependencies>>=
   use system_dependencies, only: HOPPET_AVAILABLE
 <<Features: cases>>=
   case ("hoppet")
      if (HOPPET_AVAILABLE) then
         result = "yes"
      end if
      help = "PDF evolution package"
 @
 <<Features: print>>=
   call print_check ("fastjet")
 <<Features: dependencies>>=
   use jets, only: fastjet_available
 <<Features: cases>>=
   case ("fastjet")
      if (fastjet_available ()) then
         result = "yes"
      end if
      help = "jet-clustering package"
 @
 <<Features: print>>=
   call print_check ("Pythia6")
 <<Features: dependencies>>=
   use system_dependencies, only: PYTHIA6_AVAILABLE
 <<Features: cases>>=
   case ("pythia6")
      if (PYTHIA6_AVAILABLE) then
         result = "yes"
      end if
      help = "direct access for shower/hadronization"
 @
 <<Features: print>>=
   call print_check ("Pythia8")
 <<Features: dependencies>>=
   use system_dependencies, only: PYTHIA8_AVAILABLE
 <<Features: cases>>=
   case ("pythia8")
      if (PYTHIA8_AVAILABLE) then
         result = "yes"
      end if
      help = "direct access for shower/hadronization"
 @
 <<Features: print>>=
   call print_check ("StdHEP")
 <<Features: cases>>=
   case ("stdhep")
      result = "yes"
      help = "event I/O format"
 @
 <<Features: print>>=
   call print_check ("HepMC")
 <<Features: dependencies>>=
   use hepmc_interface, only: hepmc_is_available
 <<Features: cases>>=
   case ("hepmc")
      if (hepmc_is_available ()) then
         result = "yes"
      end if
      help = "event I/O format"
 @
 <<Features: print>>=
   call print_check ("LCIO")
 <<Features: dependencies>>=
   use lcio_interface, only: lcio_is_available
 <<Features: cases>>=
   case ("lcio")
      if (lcio_is_available ()) then
         result = "yes"
      end if
      help = "event I/O format"
 @
 <<Features: print>>=
   call print_check ("MetaPost")
 <<Features: dependencies>>=
   use system_dependencies, only: EVENT_ANALYSIS
 <<Features: cases>>=
   case ("metapost")
      result = EVENT_ANALYSIS
      help = "graphical event analysis via LaTeX/MetaPost"
 @
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Driver program}
 The main program handles command options, initializes the environment,
 and runs WHIZARD in a particular mode (interactive, file, standard
 input).
 
 This is also used in the C interface:
 <<Main: cmdline arg len declaration>>=
   integer, parameter :: CMDLINE_ARG_LEN = 1000
 @ %def CMDLINE_ARG_LEN
 @
 The actual main program:
 <<[[main.f90]]>>=
 <<File header>>
 
 program main
 
 <<Use strings>>
   use system_dependencies
   use diagnostics
   use ifiles
   use os_interface
   use rt_data, only: show_description_of_string, show_tex_descriptions
   use whizard
 
   use cmdline_options
   use features
 
 <<Use mpi f08>>
 
   implicit none
 
 <<Main: cmdline arg len declaration>>
 
 !!! (WK 02/2016) Interface for the separate external routine below
   interface
      subroutine print_usage ()
      end subroutine print_usage
   end interface
 
 ! Main program variable declarations
   character(CMDLINE_ARG_LEN) :: arg
   character(2) :: option
   type(string_t) :: long_option, value
   integer :: i, j, arg_len, arg_status
   logical :: look_for_options
   logical :: interactive
   logical :: banner
   type(string_t) :: job_id, files, this, model, default_lib, library, libraries
   type(string_t) :: logfile, query_string
   logical :: user_code_enable = .false.
   integer :: n_user_src = 0, n_user_lib = 0
   type(string_t) :: user_src, user_lib, user_target
   type(paths_t) :: paths
   type(string_t) :: pack_arg, unpack_arg
   type(string_t), dimension(:), allocatable :: pack_args, unpack_args
   type(string_t), dimension(:), allocatable :: tmp_strings
   logical :: rebuild_library, rebuild_user
   logical :: rebuild_phs, rebuild_grids, rebuild_events
   logical :: recompile_library
   type(ifile_t) :: commands
-  type(string_t) :: command
+  type(string_t) :: command, cmdfile
+  integer :: cmdfile_unit
+  logical :: cmdfile_exists
 
   type(whizard_options_t), allocatable :: options
   type(whizard_t), allocatable, target :: whizard_instance
 
   ! Exit status
   logical :: quit = .false.
   integer :: quit_code = 0
 
   ! Initial values
   look_for_options = .true.
   interactive = .false.
   job_id = ""
   files = ""
   model = "SM"
   default_lib = "default_lib"
   library = ""
   libraries = ""
   banner = .true.
   logging = .true.
   msg_level = RESULT
   logfile = "whizard.log"
   user_src = ""
   user_lib = ""
   user_target = ""
   rebuild_library = .false.
   rebuild_user = .false.
   rebuild_phs = .false.
   rebuild_grids = .false.
   rebuild_events = .false.
   recompile_library = .false.
   call paths_init (paths)
 
 <<Main: MPI init>>
 
   ! Read and process options
   call init_options (print_usage)
   i = 0
   SCAN_CMDLINE: do
      i = i + 1
      call get_command_argument (i, arg, arg_len, arg_status)
      select case (arg_status)
      case (0)
      case (-1)
         call msg_error (" Command argument truncated: '" // arg // "'")
      case default
         exit SCAN_CMDLINE
      end select
      if (look_for_options) then
         select case (arg(1:2))
         case ("--")
            value = trim (arg)
            call split (value, long_option, "=")
            select case (char (long_option))
            case ("--version")
               call no_option_value (long_option, value)
               call print_version (); stop
            case ("--help")
               call no_option_value (long_option, value)
               call print_usage (); stop
            case ("--prefix")
               paths%prefix = get_option_value (i, long_option, value)
               cycle scan_cmdline
            case ("--exec-prefix")
               paths%exec_prefix = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--bindir")
               paths%bindir = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--libdir")
               paths%libdir = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--includedir")
               paths%includedir = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--datarootdir")
               paths%datarootdir = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--libtool")
               paths%libtool = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--lhapdfdir")
               paths%lhapdfdir = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--check")
               call print_usage ()
               call msg_fatal ("Option --check not supported &
                    &(for unit tests, run whizard_ut instead)")
            case ("--show-config")
               call no_option_value (long_option, value)
               call print_features (); stop
            case ("--execute")
               command = get_option_value (i, long_option, value)
               call ifile_append (commands, command)
               cycle SCAN_CMDLINE
+           case ("--file")
+              cmdfile = get_option_value (i, long_option, value)
+              inquire (file=char(cmdfile), exist=cmdfile_exists)
+              if (cmdfile_exists) then
+                 open (newunit=cmdfile_unit, file=char(cmdfile), &
+                      action="read", status="old")
+                 call ifile_append (commands, cmdfile_unit)
+                 close (cmdfile_unit)
+              else
+                 call msg_error &
+                      ("Sindarin file '" // char (cmdfile) // "' not found")
+              end if
+              cycle SCAN_CMDLINE
            case ("--interactive")
               call no_option_value (long_option, value)
               interactive = .true.
               cycle SCAN_CMDLINE
            case ("--job-id")
               job_id = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--library")
               library = get_option_value (i, long_option, value)
               libraries = libraries // " " // library
               cycle SCAN_CMDLINE
            case ("--no-library")
               call no_option_value (long_option, value)
               default_lib = ""
               library = ""
               libraries = ""
               cycle SCAN_CMDLINE
            case ("--localprefix")
               paths%localprefix = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--logfile")
               logfile = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--no-logfile")
               call no_option_value (long_option, value)
               logfile = ""
               cycle SCAN_CMDLINE
            case ("--logging")
               call no_option_value (long_option, value)
               logging = .true.
               cycle SCAN_CMDLINE
            case ("--no-logging")
               call no_option_value (long_option, value)
               logging = .false.
               cycle SCAN_CMDLINE
            case ("--query")
               call no_option_value (long_option, value)
               query_string = get_option_value (i, long_option, value)
               call show_description_of_string (query_string)
               call exit (0)
            case ("--generate-variables-tex")
               call no_option_value (long_option, value)
               call show_tex_descriptions ()
               call exit (0)
            case ("--debug")
               call no_option_value (long_option, value)
               call set_debug_levels (get_option_value (i, long_option, value))
               cycle SCAN_CMDLINE
            case ("--debug2")
               call no_option_value (long_option, value)
               call set_debug2_levels (get_option_value (i, long_option, value))
               cycle SCAN_CMDLINE
            case ("--single-event")
               call no_option_value (long_option, value)
               single_event = .true.
               cycle SCAN_CMDLINE
            case ("--banner")
               call no_option_value (long_option, value)
               banner = .true.
               cycle SCAN_CMDLINE
            case ("--no-banner")
               call no_option_value (long_option, value)
               banner = .false.
               cycle SCAN_CMDLINE
            case ("--pack")
               pack_arg = get_option_value (i, long_option, value)
               if (allocated (pack_args)) then
                  call move_alloc (from=pack_args, to=tmp_strings)
                  allocate (pack_args (size (tmp_strings)+1))
                  pack_args(1:size(tmp_strings)) = tmp_strings
               else
                  allocate (pack_args (1))
               end if
               pack_args(size(pack_args)) = pack_arg
               cycle SCAN_CMDLINE
            case ("--unpack")
               unpack_arg = get_option_value (i, long_option, value)
               if (allocated (unpack_args)) then
                  call move_alloc (from=unpack_args, to=tmp_strings)
                  allocate (unpack_args (size (tmp_strings)+1))
                  unpack_args(1:size(tmp_strings)) = tmp_strings
               else
                  allocate (unpack_args (1))
               end if
               unpack_args(size(unpack_args)) = unpack_arg
               cycle SCAN_CMDLINE
            case ("--model")
               model = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--no-model")
               call no_option_value (long_option, value)
               model = ""
               cycle SCAN_CMDLINE
            case ("--rebuild")
               call no_option_value (long_option, value)
               rebuild_library = .true.
               rebuild_user = .true.
               rebuild_phs = .true.
               rebuild_grids = .true.
               rebuild_events = .true.
               cycle SCAN_CMDLINE
            case ("--no-rebuild")
               call no_option_value (long_option, value)
               rebuild_library = .false.
               recompile_library = .false.
               rebuild_user = .false.
               rebuild_phs = .false.
               rebuild_grids = .false.
               rebuild_events = .false.
               cycle SCAN_CMDLINE
            case ("--rebuild-library")
               call no_option_value (long_option, value)
               rebuild_library = .true.
               cycle SCAN_CMDLINE
            case ("--rebuild-user")
               call no_option_value (long_option, value)
               rebuild_user = .true.
               cycle SCAN_CMDLINE
            case ("--rebuild-phase-space")
               call no_option_value (long_option, value)
               rebuild_phs = .true.
               cycle SCAN_CMDLINE
            case ("--rebuild-grids")
               call no_option_value (long_option, value)
               rebuild_grids = .true.
               cycle SCAN_CMDLINE
            case ("--rebuild-events")
               call no_option_value (long_option, value)
               rebuild_events = .true.
               cycle SCAN_CMDLINE
            case ("--recompile")
               call no_option_value (long_option, value)
               recompile_library = .true.
               rebuild_grids = .true.
               cycle SCAN_CMDLINE
            case ("--user")
               user_code_enable = .true.
               cycle SCAN_CMDLINE
            case ("--user-src")
               if (user_src == "") then
                  user_src = get_option_value (i, long_option, value)
               else
                  user_src = user_src // " " &
                       // get_option_value (i, long_option, value)
               end if
               n_user_src = n_user_src + 1
               cycle SCAN_CMDLINE
            case ("--user-lib")
               if (user_lib == "") then
                  user_lib = get_option_value (i, long_option, value)
               else
                  user_lib = user_lib // " " &
                       // get_option_value (i, long_option, value)
               end if
               n_user_lib = n_user_lib + 1
               cycle SCAN_CMDLINE
            case ("--user-target")
               user_target = get_option_value (i, long_option, value)
               cycle SCAN_CMDLINE
            case ("--write-syntax-tables")
               call no_option_value (long_option, value)
         call init_syntax_tables ()
               call write_syntax_tables ()
               call final_syntax_tables ()
               stop
               cycle SCAN_CMDLINE
            case default
               call print_usage ()
               call msg_fatal ("Option '" // trim (arg) // "' not recognized")
            end select
         end select
         select case (arg(1:1))
         case ("-")
            j = 1
            if (len_trim (arg) == 1) then
               look_for_options = .false.
            else
               SCAN_SHORT_OPTIONS: do
                  j = j + 1
                  if (j > len_trim (arg)) exit SCAN_SHORT_OPTIONS
                  option = "-" // arg(j:j)
                  select case (option)
                  case ("-V")
                     call print_version (); stop
                  case ("-?", "-h")
                     call print_usage (); stop
                  case ("-e")
                     command = get_option_value (i, var_str (option))
                     call ifile_append (commands, command)
                     cycle SCAN_CMDLINE
+                 case ("-f")
+                    cmdfile = get_option_value (i, var_str (option))
+                    inquire (file=char(cmdfile), exist=cmdfile_exists)
+                    if (cmdfile_exists) then
+                       open (newunit=cmdfile_unit, file=char(cmdfile), &
+                            action="read", status="old")
+                       call ifile_append (commands, cmdfile_unit)
+                       close (cmdfile_unit)
+                    else
+                       call msg_error ("Sindarin file '" &
+                            // char (cmdfile) // "' not found")
+                    end if
+                    cycle SCAN_CMDLINE
                  case ("-i")
                     interactive = .true.
                     cycle SCAN_SHORT_OPTIONS
                  case ("-J")
                     if (j == len_trim (arg)) then
                        job_id = get_option_value (i, var_str (option))
                     else
                        job_id = trim (arg(j+1:))
                     end if
                     cycle SCAN_CMDLINE
                  case ("-l")
                     if (j == len_trim (arg)) then
                        library = get_option_value (i, var_str (option))
                     else
                        library = trim (arg(j+1:))
                     end if
                     libraries = libraries // " " // library
                     cycle SCAN_CMDLINE
                  case ("-L")
                     if (j == len_trim (arg)) then
                        logfile = get_option_value (i, var_str (option))
                     else
                        logfile = trim (arg(j+1:))
                     end if
                     cycle SCAN_CMDLINE
                  case ("-m")
                     if (j < len_trim (arg))  call msg_fatal &
                          ("Option '" // option // "' needs a value")
                     model = get_option_value (i, var_str (option))
                     cycle SCAN_CMDLINE
                  case ("-q")
                     call no_option_value (long_option, value)
                     query_string = get_option_value (i, long_option, value)
                     call show_description_of_string (query_string)
                     call exit (0)
                  case ("-r")
                     rebuild_library = .true.
                     rebuild_user = .true.
                     rebuild_phs = .true.
                     rebuild_grids = .true.
                     rebuild_events = .true.
                     cycle SCAN_SHORT_OPTIONS
                  case ("-u")
                     user_code_enable = .true.
                     cycle SCAN_SHORT_OPTIONS
                  case default
                     call print_usage ()
                     call msg_fatal &
                          ("Option '" // option // "' not recognized")
                  end select
               end do SCAN_SHORT_OPTIONS
            end if
         case default
            files = files // " " // trim (arg)
         end select
      else
         files = files // " " // trim (arg)
      end if
   end do SCAN_CMDLINE
 
   ! Overall initialization
   if (logfile /= "")  call logfile_init (logfile)
   if (banner)  call msg_banner ()
 
    allocate (options)
    allocate (whizard_instance)
 
    if (.not. quit) then
 
       ! Set options and initialize the whizard object
       options%job_id = job_id
       if (allocated (pack_args)) then
          options%pack_args = pack_args
       else
          allocate (options%pack_args (0))
       end if
       if (allocated (unpack_args)) then
          options%unpack_args = unpack_args
       else
          allocate (options%unpack_args (0))
       end if
       options%preload_model = model
       options%default_lib = default_lib
       options%preload_libraries = libraries
       options%rebuild_library = rebuild_library
       options%recompile_library = recompile_library
       options%rebuild_user = rebuild_user
       options%rebuild_phs = rebuild_phs
       options%rebuild_grids = rebuild_grids
       options%rebuild_events = rebuild_events
     <<Main: dependent flags>>
 
       call whizard_instance%init (options, paths, logfile)
 
       call mask_term_signals ()
 
    end if
 
    ! Run commands given on the command line
    if (.not. quit .and. ifile_get_length (commands) > 0) then
       call whizard_instance%process_ifile (commands, quit, quit_code)
    end if
 
    if (.not. quit) then
       ! Process commands from standard input
       if (.not. interactive .and. files == "") then
          call whizard_instance%process_stdin (quit, quit_code)
 
          ! ... or process commands from file
       else
          files = trim (adjustl (files))
          SCAN_FILES: do while (files /= "")
             call split (files, this, " ")
             call whizard_instance%process_file (this, quit, quit_code)
             if (quit)  exit SCAN_FILES
          end do SCAN_FILES
 
       end if
   end if
 
   ! Enter an interactive shell if requested
   if (.not. quit .and. interactive) then
      call whizard_instance%shell (quit_code)
   end if
 
   ! Overall finalization
   call ifile_final (commands)
 
   deallocate (options)
 
   call whizard_instance%final ()
   deallocate (whizard_instance)
 
 <<Main: MPI finalize>>
 
   call terminate_now_if_signal ()
   call release_term_signals ()
   call msg_terminate (quit_code = quit_code)
 
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 contains
 
   subroutine print_version ()
     print "(A)", "WHIZARD " // WHIZARD_VERSION
     print "(A)", "Copyright (C) 1999-2019 Wolfgang Kilian, Thorsten Ohl, Juergen Reuter"
     print "(A)", "              ---------------------------------------                "
     print "(A)", "This is free software; see the source for copying conditions.  There is NO"
     print "(A)", "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
     print *
   end subroutine print_version
 
 end program main
 
 !!! (WK 02/2016)
 !!! Separate subroutine, because this becomes a procedure pointer target
 !!! Internal procedures as targets are not supported by some compilers.
 
   subroutine print_usage ()
     use system_dependencies, only: WHIZARD_VERSION
     print "(A)", "WHIZARD " // WHIZARD_VERSION
     print "(A)", "Usage: whizard [OPTIONS] [FILE]"
     print "(A)", "Run WHIZARD with the command list taken from FILE(s)"
     print "(A)", "Options for resetting default directories and tools" &
             // "(GNU naming conventions):"
     print "(A)", "    --prefix DIR"
     print "(A)", "    --exec-prefix DIR"
     print "(A)", "    --bindir DIR"
     print "(A)", "    --libdir DIR"
     print "(A)", "    --includedir DIR"
     print "(A)", "    --datarootdir DIR"
     print "(A)", "    --libtool LOCAL_LIBTOOL"
     print "(A)", "    --lhapdfdir DIR   (PDF sets directory)"
     print "(A)", "Other options:"
     print "(A)", "-h, --help            display this help and exit"
     print "(A)", "    --banner          display banner at startup (default)"
     print "(A)", "    --debug AREA      switch on debug output for AREA."
     print "(A)", "                      AREA can be one of Whizard's src dirs or 'all'"
     print "(A)", "    --debug2 AREA     switch on more verbose debug output for AREA."
     print "(A)", "    --single-event    only compute one phase-space point (for debugging)"
     print "(A)", "-e, --execute CMDS    execute SINDARIN CMDS before reading FILE(s)"
+    print "(A)", "-f, --file CMDFILE    execute SINDARIN from CMDFILE before reading FILE(s)"
     print "(A)", "-i, --interactive     run interactively after reading FILE(s)"
     print "(A)", "-J, --job-id STRING   set job ID to STRING (default: empty)"
     print "(A)", "-l, --library LIB     preload process library NAME"
     print "(A)", "    --localprefix DIR"
     print "(A)", "                      search in DIR for local models (default: ~/.whizard)"
     print "(A)", "-L, --logfile FILE    write log to FILE (default: 'whizard.log'"
     print "(A)", "    --logging         switch on logging at startup (default)"
     print "(A)", "-m, --model NAME      preload model NAME (default: 'SM')"
     print "(A)", "    --no-banner       do not display banner at startup"
     print "(A)", "    --no-library      do not preload process library"
     print "(A)", "    --no-logfile      do not write a logfile"
     print "(A)", "    --no-logging      switch off logging at startup"
     print "(A)", "    --no-model        do not preload a model"
     print "(A)", "    --no-rebuild      do not force rebuilding"
     print "(A)", "    --pack DIR        tar/gzip DIR after job"
     print "(A)", "-q, --query VARIABLE  display documentation of VARIABLE"
     print "(A)", "-r, --rebuild         rebuild all (see below)"
     print "(A)", "    --rebuild-library"
     print "(A)", "                      rebuild process code library"
     print "(A)", "    --rebuild-user    rebuild user-provided code"
     print "(A)", "    --rebuild-phase-space"
     print "(A)", "                      rebuild phase-space configuration"
     print "(A)", "    --rebuild-grids   rebuild integration grids"
     print "(A)", "    --rebuild-events  rebuild event samples"
     print "(A)", "    --recompile       recompile process code"
     print "(A)", "    --show-config     show build-time configuration"
     print "(A)", "    --unpack FILE     untar/gunzip FILE before job"
     print "(A)", "-u  --user            enable user-provided code"
     print "(A)", "    --user-src FILE   user-provided source file"
     print "(A)", "    --user-lib FILE   user-provided library file"
     print "(A)", "    --user-target BN  basename of created user library (default: user)"
     print "(A)", "-V, --version         output version information and exit"
     print "(A)", "    --write-syntax-tables"
     print "(A)", "                      write the internal syntax tables to files and exit"
     print "(A)", "-                     further options are taken as filenames"
     print *
     print "(A)", "With no FILE, read standard input."
   end subroutine print_usage
 
 @ %def main
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Driver program for the unit tests}
 This is a variant of the above main program that takes unit-test names
 as command-line options and runs those tests.
 <<[[main_ut.f90]]>>=
 <<File header>>
 
 program main_ut
 
 <<Use strings>>
   use unit_tests
   use io_units
   use system_dependencies
   use diagnostics
   use os_interface
 
   use cmdline_options
 
   use model_testbed !NODEP!
 <<Use mpi f08>>
 
 <<Main: use tests>>
 
   implicit none
 
 <<Main: cmdline arg len declaration>>
 
 !!! (WK 02/2016) Interface for the separate external routine below
   interface
      subroutine print_usage ()
      end subroutine print_usage
   end interface
 
   ! Main program variable declarations
   character(CMDLINE_ARG_LEN) :: arg
   character(2) :: option
   type(string_t) :: long_option, value
   integer :: i, j, arg_len, arg_status
   logical :: look_for_options
   logical :: banner
   type(string_t) :: check, checks
   type(test_results_t) :: test_results
   logical :: success
 
   ! Exit status
   integer :: quit_code = 0
 
   ! Initial values
   look_for_options = .true.
   banner = .true.
   logging = .false.
   msg_level = RESULT
   check = ""
   checks = ""
 
 <<Main: MPI init>>
 
   ! Read and process options
   call init_options (print_usage)
   i = 0
   SCAN_CMDLINE: do
      i = i + 1
      call get_command_argument (i, arg, arg_len, arg_status)
      select case (arg_status)
      case (0)
      case (-1)
         call msg_error (" Command argument truncated: '" // arg // "'")
      case default
         exit SCAN_CMDLINE
      end select
      if (look_for_options) then
         select case (arg(1:2))
         case ("--")
            value = trim (arg)
            call split (value, long_option, "=")
            select case (char (long_option))
            case ("--version")
               call no_option_value (long_option, value)
               call print_version (); stop
            case ("--help")
               call no_option_value (long_option, value)
               call print_usage (); stop
            case ("--banner")
               call no_option_value (long_option, value)
               banner = .true.
               cycle SCAN_CMDLINE
            case ("--no-banner")
               call no_option_value (long_option, value)
               banner = .false.
               cycle SCAN_CMDLINE
            case ("--check")
               check = get_option_value (i, long_option, value)
               checks = checks // " " // check
               cycle SCAN_CMDLINE
            case ("--debug")
               call no_option_value (long_option, value)
               call set_debug_levels (get_option_value (i, long_option, value))
               cycle SCAN_CMDLINE
            case ("--debug2")
               call no_option_value (long_option, value)
               call set_debug2_levels (get_option_value (i, long_option, value))
               cycle SCAN_CMDLINE
            case default
               call print_usage ()
               call msg_fatal ("Option '" // trim (arg) // "' not recognized")
            end select
         end select
         select case (arg(1:1))
         case ("-")
            j = 1
            if (len_trim (arg) == 1) then
               look_for_options = .false.
            else
               SCAN_SHORT_OPTIONS: do
                  j = j + 1
                  if (j > len_trim (arg)) exit SCAN_SHORT_OPTIONS
                  option = "-" // arg(j:j)
                  select case (option)
                  case ("-V")
                     call print_version (); stop
                  case ("-?", "-h")
                     call print_usage (); stop
                  case default
                     call print_usage ()
                     call msg_fatal &
                          ("Option '" // option // "' not recognized")
                  end select
               end do SCAN_SHORT_OPTIONS
            end if
         case default
            call print_usage ()
            call msg_fatal ("Option '" // trim (arg) // "' not recognized")
         end select
      else
         call print_usage ()
         call msg_fatal ("Option '" // trim (arg) // "' not recognized")
      end if
   end do SCAN_CMDLINE
 
   ! Overall initialization
   if (banner)  call msg_banner ()
 
    ! Run any self-checks (and no commands)
    if (checks /= "") then
       checks = trim (adjustl (checks))
       RUN_CHECKS: do while (checks /= "")
          call split (checks, check, " ")
          call whizard_check (check, test_results)
       end do RUN_CHECKS
       call test_results%wrapup (6, success)
       if (.not. success)  quit_code = 7
    end if
 
  <<Main: MPI finalize>>
 
    call msg_terminate (quit_code = quit_code)
 
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 contains
 
   subroutine print_version ()
     print "(A)", "WHIZARD " // WHIZARD_VERSION // " (unit test driver)"
     print "(A)", "Copyright (C) 1999-2019 Wolfgang Kilian, Thorsten Ohl, Juergen Reuter"
     print "(A)", "              ---------------------------------------                "
     print "(A)", "This is free software; see the source for copying conditions.  There is NO"
     print "(A)", "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
     print *
   end subroutine print_version
 
 <<Main: tests>>
 
 end program main_ut
 
 !!! (WK 02/2016)
 !!! Separate subroutine, because this becomes a procedure pointer target
 !!! Internal procedures as targets are not supported by some compilers.
 
   subroutine print_usage ()
     use system_dependencies, only: WHIZARD_VERSION
     print "(A)", "WHIZARD " // WHIZARD_VERSION // " (unit test driver)"
     print "(A)", "Usage: whizard_ut [OPTIONS] [FILE]"
     print "(A)", "Run WHIZARD unit tests as given on the command line"
     print "(A)", "Options:"
     print "(A)", "-h, --help            display this help and exit"
     print "(A)", "    --banner          display banner at startup (default)"
     print "(A)", "    --no-banner       do not display banner at startup"
     print "(A)", "    --debug AREA      switch on debug output for AREA."
     print "(A)", "                      AREA can be one of Whizard's src dirs or 'all'"
     print "(A)", "    --debug2 AREA     switch on more verbose debug output for AREA."
     print "(A)", "-V, --version         output version information and exit"
     print "(A)", "    --check TEST      run unit test TEST"
   end subroutine print_usage
 @ %def main_ut
 @
 <<Main: MPI init>>=
 @
 <<Main: MPI finalize>>=
 @
 @ MPI init.
 <<MPI: Main: MPI init>>=
   call MPI_init ()
 <<MPI: Main: MPI finalize>>=
   call MPI_finalize ()
 @ %def MPI_init MPI_finalize
 <<Main: dependent flags>>=
 @
 Every rebuild action is forbidden for the slave workers except
 [[rebuild_grids]], which is handled correctly inside the corresponding
 integration object.
 <<MPI: Main: dependent flags>>=
   if (.not. mpi_is_comm_master ()) then
     options%rebuild_library = .false.
     options%recompile_library = .false.
     options%rebuild_user = .false.
     options%rebuild_phs = .false.
     options%rebuild_events = .false.
   end if
 @
 \subsection{Self-tests}
 For those self-tests, we need some auxiliary routines that provide an
 enviroment.  The environment depends on things that are not available at the
 level of the module that we want to test.
 
 \subsubsection{Testbed for event I/O}
 This subroutine prepares a test process with a single event.  All objects are
 allocated via anonymous pointers, because we want to recover the pointers and
 delete the objects in a separate procedure.
 <<Main: tests>>=
   subroutine prepare_eio_test (event, unweighted, n_alt)
     use variables, only: var_list_t
     use model_data
     use process, only: process_t
     use instances, only: process_instance_t
     use processes_ut, only: prepare_test_process
     use event_base
     use events
 
     class(generic_event_t), intent(inout), pointer :: event
     logical, intent(in), optional :: unweighted
     integer, intent(in), optional :: n_alt
     type(model_data_t), pointer :: model
     type(var_list_t) :: var_list
     type(process_t), pointer :: proc
     type(process_instance_t), pointer :: process_instance
 
     allocate (model)
     call model%init_test ()
 
     allocate (proc)
     allocate (process_instance)
 
     call prepare_test_process (proc, process_instance, model, &
          run_id = var_str ("run_test"))
     call process_instance%setup_event_data ()
 
     call model%final ()
     deallocate (model)
 
     allocate (event_t :: event)
     select type (event)
     type is (event_t)
        if (present (unweighted)) then
           call var_list%append_log (&
                var_str ("?unweighted"), unweighted, &
                intrinsic = .true.)
        else
           call var_list%append_log (&
                var_str ("?unweighted"), .true., &
                intrinsic = .true.)
        end if
        call var_list%append_string (&
             var_str ("$sample_normalization"), &
             var_str ("auto"), intrinsic = .true.)
        call event%basic_init (var_list, n_alt)
        call event%connect (process_instance, proc%get_model_ptr ())
        call var_list%final ()
     end select
 
   end subroutine prepare_eio_test
 
 @ %def prepare_eio_test_event
 @ Recover those pointers, finalize the objects and deallocate.
 <<Main: tests>>=
   subroutine cleanup_eio_test (event)
     use model_data
     use process, only: process_t
     use instances, only: process_instance_t
     use processes_ut, only: cleanup_test_process
     use event_base
     use events
 
     class(generic_event_t), intent(inout), pointer :: event
     type(process_t), pointer :: proc
     type(process_instance_t), pointer :: process_instance
 
     select type (event)
     type is (event_t)
        proc => event%get_process_ptr ()
        process_instance => event%get_process_instance_ptr ()
        call cleanup_test_process (proc, process_instance)
        deallocate (process_instance)
        deallocate (proc)
        call event%final ()
     end select
     deallocate (event)
 
   end subroutine cleanup_eio_test
 
 @ %def cleanup_eio_test_event
 @ Assign those procedures to appropriate pointers (module variables) in the
 [[eio_base]] module, so they can be called as if they were module procedures.
 <<Main: use tests>>=
   use eio_base_ut, only: eio_prepare_test
   use eio_base_ut, only: eio_cleanup_test
 <<Main: prepare testbed>>=
   eio_prepare_test => prepare_eio_test
   eio_cleanup_test => cleanup_eio_test
 @
 \subsubsection{Any Model}
 This procedure reads any model from file and, optionally, assigns a
 var-list pointer.  If the model pointer is still null, we allocate the model
 object first, with concrete type [[model_t]].  This is a service for modules
 which do just have access to the [[model_data_t]] base type.
 <<Main: tests>>=
   subroutine prepare_whizard_model (model, name, vars)
   <<Use strings>>
     use os_interface
     use model_data
     use var_base
     use models
     class(model_data_t), intent(inout), pointer :: model
     type(string_t), intent(in) :: name
     class(vars_t), pointer, intent(out), optional :: vars
     type(os_data_t) :: os_data
     call syntax_model_file_init ()
     call os_data%init ()
     if (.not. associated (model))  allocate (model_t :: model)
     select type (model)
     type is (model_t)
        call model%read (name // ".mdl", os_data)
        if (present (vars)) then
           vars => model%get_var_list_ptr ()
        end if
     end select
   end subroutine prepare_whizard_model
 
 @ %def prepare_whizard_model
 @ Cleanup after use.  Includes deletion of the model-file syntax.
 <<Main: tests>>=
   subroutine cleanup_whizard_model (model)
     use model_data
     use models
     class(model_data_t), intent(inout), target :: model
     call model%final ()
     call syntax_model_file_final ()
   end subroutine cleanup_whizard_model
 
 @ %def cleanup_whizard_model
 @ Assign those procedures to appropriate pointers (module variables) in the
 [[model_testbed]] module, so they can be called as if they were module
 procedures.
 <<Main: prepare testbed>>=
   prepare_model => prepare_whizard_model
   cleanup_model => cleanup_whizard_model
 @
 \subsubsection{Fallback model: hadrons}
 Some event format tests require the hadronic SM implementation, which
 has to be read from file.  We provide the functionality here, so the
 tests do not depend on model I/O.
 <<Main: tests>>=
   subroutine prepare_fallback_model (model)
     use model_data
     class(model_data_t), intent(inout), pointer :: model
     call prepare_whizard_model (model, var_str ("SM_hadrons"))
   end subroutine prepare_fallback_model
 
 @ %def prepare_fallback_model
 @ Assign those procedures to appropriate pointers (module variables) in the
 [[eio_base]] module, so they can be called as if they were module procedures.
 <<Main: use tests>>=
   use eio_base_ut, only: eio_prepare_fallback_model
   use eio_base_ut, only: eio_cleanup_fallback_model
 <<Main: prepare testbed>>=
   eio_prepare_fallback_model => prepare_fallback_model
   eio_cleanup_fallback_model => cleanup_model
 @
 \subsubsection{Access to the test random-number generator}
 This generator is not normally available for the dispatcher.  We assign an
 additional dispatch routine to the hook in the [[dispatch]] module
 which will be checked before the default rule.
 <<Main: use tests>>=
   use dispatch_rng, only: dispatch_rng_factory_fallback
   use dispatch_rng_ut, only: dispatch_rng_factory_test
 <<Main: prepare testbed>>=
   dispatch_rng_factory_fallback => dispatch_rng_factory_test
 @
 \subsubsection{Access to the test structure functions}
 These are not normally available for the dispatcher.  We assign an
 additional dispatch routine to the hook in the [[dispatch]] module
 which will be checked before the default rule.
 <<Main: use tests>>=
   use dispatch_beams, only: dispatch_sf_data_extra
   use dispatch_ut, only: dispatch_sf_data_test
 <<Main: prepare testbed>>=
   dispatch_sf_data_extra => dispatch_sf_data_test
 @
 \subsubsection{Procedure for Checking}
 This is for developers only, but needs a well-defined interface.
 <<Main: tests>>=
   subroutine whizard_check (check, results)
     type(string_t), intent(in) :: check
     type(test_results_t), intent(inout) :: results
     type(os_data_t) :: os_data
     integer :: u
     call os_data%init ()
     u = free_unit ()
     open (u, file="whizard_check." // char (check) // ".log", &
          action="write", status="replace")
     call msg_message (repeat ('=', 76), 0)
     call msg_message ("Running self-test: " // char (check), 0)
     call msg_message (repeat ('-', 76), 0)
   <<Main: prepare testbed>>
     select case (char (check))
   <<Main: test cases>>
     case ("all")
      <<Main: all tests>>
     case default
        call msg_fatal ("Self-test '" // char (check) // "' not implemented.")
     end select
     close (u)
   end subroutine whizard_check
 
 @ %def whizard_check
 @
 \subsection{Unit test references}
 \subsubsection{Formats}
 <<Main: use tests>>=
   use formats_ut, only: format_test
 <<Main: test cases>>=
   case ("formats")
      call format_test (u, results)
 <<Main: all tests>>=
   call format_test (u, results)
 @
 \subsubsection{MD5}
 <<Main: use tests>>=
   use md5_ut, only: md5_test
 <<Main: test cases>>=
   case ("md5")
      call md5_test (u, results)
 <<Main: all tests>>=
   call md5_test (u, results)
 @
 \subsubsection{OS Interface}
 <<Main: use tests>>=
   use os_interface_ut, only: os_interface_test
 <<Main: test cases>>=
   case ("os_interface")
      call os_interface_test (u, results)
 <<Main: all tests>>=
   call os_interface_test (u, results)
 @
 \subsubsection{Sorting}
 <<Main: use tests>>=
   use sorting_ut, only: sorting_test
 <<Main: test cases>>=
   case ("sorting")
      call sorting_test (u, results)
 <<Main: all tests>>=
   call sorting_test (u, results)
 @
 \subsubsection{Grids}
 <<Main: use tests>>=
   use grids_ut, only: grids_test
 <<Main: test cases>>=
   case ("grids")
      call grids_test (u, results)
 <<Main: all tests>>=
   call grids_test (u, results)
 @
 \subsubsection{Solver}
 <<Main: use tests>>=
   use solver_ut, only: solver_test
 <<Main: test cases>>=
   case ("solver")
      call solver_test (u, results)
 <<Main: all tests>>=
   call solver_test (u, results)
 @
 \subsubsection{CPU Time}
 <<Main: use tests>>=
   use cputime_ut, only: cputime_test
 <<Main: test cases>>=
   case ("cputime")
      call cputime_test (u, results)
 <<Main: all tests>>=
   call cputime_test (u, results)
 @
 \subsubsection{SM QCD}
 <<Main: use tests>>=
   use sm_qcd_ut, only: sm_qcd_test
 <<Main: test cases>>=
   case ("sm_qcd")
      call sm_qcd_test (u, results)
 <<Main: all tests>>=
   call sm_qcd_test (u, results)
 @
 \subsubsection{SM physics}
 <<Main: use tests>>=
   use sm_physics_ut, only: sm_physics_test
 <<Main: test cases>>=
   case ("sm_physics")
      call sm_physics_test (u, results)
 <<Main: all tests>>=
   call sm_physics_test (u, results)
 @
 \subsubsection{Lexers}
 <<Main: use tests>>=
   use lexers_ut, only: lexer_test
 <<Main: test cases>>=
   case ("lexers")
      call lexer_test (u, results)
 <<Main: all tests>>=
   call lexer_test (u, results)
 @
 \subsubsection{Parser}
 <<Main: use tests>>=
   use parser_ut, only: parse_test
 <<Main: test cases>>=
   case ("parser")
      call parse_test (u, results)
 <<Main: all tests>>=
   call parse_test (u, results)
 @
 \subsubsection{XML}
 <<Main: use tests>>=
   use xml_ut, only: xml_test
 <<Main: test cases>>=
   case ("xml")
      call xml_test (u, results)
 <<Main: all tests>>=
   call xml_test (u, results)
 @
 \subsubsection{Colors}
 <<Main: use tests>>=
   use colors_ut, only: color_test
 <<Main: test cases>>=
   case ("colors")
      call color_test (u, results)
 <<Main: all tests>>=
   call color_test (u, results)
 @
 \subsubsection{State matrices}
 <<Main: use tests>>=
   use state_matrices_ut, only: state_matrix_test
 <<Main: test cases>>=
   case ("state_matrices")
      call state_matrix_test (u, results)
 <<Main: all tests>>=
   call state_matrix_test (u, results)
 @
 \subsubsection{Analysis}
 <<Main: use tests>>=
   use analysis_ut, only: analysis_test
 <<Main: test cases>>=
   case ("analysis")
      call analysis_test (u, results)
 <<Main: all tests>>=
   call analysis_test (u, results)
 @
 \subsubsection{Particles}
 <<Main: use tests>>=
   use particles_ut, only: particles_test
 <<Main: test cases>>=
   case ("particles")
      call particles_test (u, results)
 <<Main: all tests>>=
   call particles_test (u, results)
 @
 \subsubsection{Models}
 <<Main: use tests>>=
   use models_ut, only: models_test
 <<Main: test cases>>=
   case ("models")
      call models_test (u, results)
 <<Main: all tests>>=
   call models_test (u, results)
 @
 \subsubsection{Auto Components}
 <<Main: use tests>>=
   use auto_components_ut, only: auto_components_test
 <<Main: test cases>>=
   case ("auto_components")
      call auto_components_test (u, results)
 <<Main: all tests>>=
   call auto_components_test (u, results)
 @
 \subsubsection{Radiation Generator}
 <<Main: use tests>>=
   use radiation_generator_ut, only: radiation_generator_test
 <<Main: test cases>>=
   case ("radiation_generator")
      call radiation_generator_test (u, results)
 <<Main: all tests>>=
   call radiation_generator_test (u, results)
 @
 \subsection{BLHA}
 <<Main: use tests>>=
   use blha_ut, only: blha_test
 <<Main: test cases>>=
   case ("blha")
      call blha_test (u, results)
 <<Main: all tests>>=
   call blha_test (u, results)
 @
 \subsubsection{Evaluators}
 <<Main: use tests>>=
   use evaluators_ut, only: evaluator_test
 <<Main: test cases>>=
   case ("evaluators")
      call evaluator_test (u, results)
 <<Main: all tests>>=
   call evaluator_test (u, results)
 @
 \subsubsection{Expressions}
 <<Main: use tests>>=
   use eval_trees_ut, only: expressions_test
 <<Main: test cases>>=
   case ("expressions")
      call expressions_test (u, results)
 <<Main: all tests>>=
   call expressions_test (u, results)
 @
 \subsubsection{Resonances}
 <<Main: use tests>>=
   use resonances_ut, only: resonances_test
 <<Main: test cases>>=
   case ("resonances")
      call resonances_test (u, results)
 <<Main: all tests>>=
   call resonances_test (u, results)
 @
 \subsubsection{PHS Trees}
 <<Main: use tests>>=
   use phs_trees_ut, only: phs_trees_test
 <<Main: test cases>>=
   case ("phs_trees")
      call phs_trees_test (u, results)
 <<Main: all tests>>=
   call phs_trees_test (u, results)
 @
 \subsubsection{PHS Forests}
 <<Main: use tests>>=
   use phs_forests_ut, only: phs_forests_test
 <<Main: test cases>>=
   case ("phs_forests")
      call phs_forests_test (u, results)
 <<Main: all tests>>=
   call phs_forests_test (u, results)
 @
 \subsubsection{Beams}
 <<Main: use tests>>=
   use beams_ut, only: beams_test
 <<Main: test cases>>=
   case ("beams")
      call beams_test (u, results)
 <<Main: all tests>>=
   call beams_test (u, results)
 @
 \subsubsection{$su(N)$ Algebra}
 <<Main: use tests>>=
   use su_algebra_ut, only: su_algebra_test
 <<Main: test cases>>=
   case ("su_algebra")
      call su_algebra_test (u, results)
 <<Main: all tests>>=
   call su_algebra_test (u, results)
 @
 \subsubsection{Bloch Vectors}
 <<Main: use tests>>=
   use bloch_vectors_ut, only: bloch_vectors_test
 <<Main: test cases>>=
   case ("bloch_vectors")
      call bloch_vectors_test (u, results)
 <<Main: all tests>>=
   call bloch_vectors_test (u, results)
 @
 \subsubsection{Polarizations}
 <<Main: use tests>>=
   use polarizations_ut, only: polarizations_test
 <<Main: test cases>>=
   case ("polarizations")
      call polarizations_test (u, results)
 <<Main: all tests>>=
   call polarizations_test (u, results)
 @
 \subsubsection{SF Aux}
 <<Main: use tests>>=
   use sf_aux_ut, only: sf_aux_test
 <<Main: test cases>>=
   case ("sf_aux")
      call sf_aux_test (u, results)
 <<Main: all tests>>=
   call sf_aux_test (u, results)
 @
 \subsubsection{SF Mappings}
 <<Main: use tests>>=
   use sf_mappings_ut, only: sf_mappings_test
 <<Main: test cases>>=
   case ("sf_mappings")
      call sf_mappings_test (u, results)
 <<Main: all tests>>=
   call sf_mappings_test (u, results)
 @
 \subsubsection{SF Base}
 <<Main: use tests>>=
   use sf_base_ut, only: sf_base_test
 <<Main: test cases>>=
   case ("sf_base")
      call sf_base_test (u, results)
 <<Main: all tests>>=
   call sf_base_test (u, results)
 @
 \subsubsection{SF PDF Builtin}
 <<Main: use tests>>=
   use sf_pdf_builtin_ut, only: sf_pdf_builtin_test
 <<Main: test cases>>=
   case ("sf_pdf_builtin")
      call sf_pdf_builtin_test (u, results)
 <<Main: all tests>>=
   call sf_pdf_builtin_test (u, results)
 @
 \subsubsection{SF LHAPDF}
 <<Main: use tests>>=
   use sf_lhapdf_ut, only: sf_lhapdf_test
 <<Main: test cases>>=
   case ("sf_lhapdf")
      call sf_lhapdf_test (u, results)
 <<Main: all tests>>=
   call sf_lhapdf_test (u, results)
 @
 \subsubsection{SF ISR}
 <<Main: use tests>>=
   use sf_isr_ut, only: sf_isr_test
 <<Main: test cases>>=
   case ("sf_isr")
      call sf_isr_test (u, results)
 <<Main: all tests>>=
   call sf_isr_test (u, results)
 @
 \subsubsection{SF EPA}
 <<Main: use tests>>=
   use sf_epa_ut, only: sf_epa_test
 <<Main: test cases>>=
   case ("sf_epa")
      call sf_epa_test (u, results)
 <<Main: all tests>>=
   call sf_epa_test (u, results)
 @
 \subsubsection{SF EWA}
 <<Main: use tests>>=
   use sf_ewa_ut, only: sf_ewa_test
 <<Main: test cases>>=
   case ("sf_ewa")
      call sf_ewa_test (u, results)
 <<Main: all tests>>=
   call sf_ewa_test (u, results)
 @
 \subsubsection{SF CIRCE1}
 <<Main: use tests>>=
   use sf_circe1_ut, only: sf_circe1_test
 <<Main: test cases>>=
   case ("sf_circe1")
      call sf_circe1_test (u, results)
 <<Main: all tests>>=
   call sf_circe1_test (u, results)
 @
 \subsubsection{SF CIRCE2}
 <<Main: use tests>>=
   use sf_circe2_ut, only: sf_circe2_test
 <<Main: test cases>>=
   case ("sf_circe2")
      call sf_circe2_test (u, results)
 <<Main: all tests>>=
   call sf_circe2_test (u, results)
 @
 \subsubsection{SF Gaussian}
 <<Main: use tests>>=
   use sf_gaussian_ut, only: sf_gaussian_test
 <<Main: test cases>>=
   case ("sf_gaussian")
      call sf_gaussian_test (u, results)
 <<Main: all tests>>=
   call sf_gaussian_test (u, results)
 @
 \subsubsection{SF Beam Events}
 <<Main: use tests>>=
   use sf_beam_events_ut, only: sf_beam_events_test
 <<Main: test cases>>=
   case ("sf_beam_events")
      call sf_beam_events_test (u, results)
 <<Main: all tests>>=
   call sf_beam_events_test (u, results)
 @
 \subsubsection{SF EScan}
 <<Main: use tests>>=
   use sf_escan_ut, only: sf_escan_test
 <<Main: test cases>>=
   case ("sf_escan")
      call sf_escan_test (u, results)
 <<Main: all tests>>=
   call sf_escan_test (u, results)
 @
 \subsubsection{PHS Base}
 <<Main: use tests>>=
   use phs_base_ut, only: phs_base_test
 <<Main: test cases>>=
   case ("phs_base")
      call phs_base_test (u, results)
 <<Main: all tests>>=
   call phs_base_test (u, results)
 @
 \subsubsection{PHS None}
 <<Main: use tests>>=
   use phs_none_ut, only: phs_none_test
 <<Main: test cases>>=
   case ("phs_none")
      call phs_none_test (u, results)
 <<Main: all tests>>=
   call phs_none_test (u, results)
 @
 \subsubsection{PHS Single}
 <<Main: use tests>>=
   use phs_single_ut, only: phs_single_test
 <<Main: test cases>>=
   case ("phs_single")
      call phs_single_test (u, results)
 <<Main: all tests>>=
   call phs_single_test (u, results)
 @
 \subsubsection{PHS Rambo}
 <<Main: use tests>>=
   use phs_rambo_ut, only: phs_rambo_test
 <<Main: test cases>>=
   case ("phs_rambo")
      call phs_rambo_test (u, results)
 <<Main: all tests>>=
   call phs_rambo_test (u, results)
 @
 \subsubsection{PHS Wood}
 <<Main: use tests>>=
   use phs_wood_ut, only: phs_wood_test
   use phs_wood_ut, only: phs_wood_vis_test
 <<Main: test cases>>=
   case ("phs_wood")
      call phs_wood_test (u, results)
   case ("phs_wood_vis")
      call phs_wood_vis_test (u, results)
 <<Main: all tests>>=
   call phs_wood_test (u, results)
   call phs_wood_vis_test (u, results)
 @
 \subsubsection{PHS FKS Generator}
 <<Main: use tests>>=
   use phs_fks_ut, only: phs_fks_generator_test
 <<Main: test cases>>=
   case ("phs_fks_generator")
      call phs_fks_generator_test (u, results)
 <<Main: all tests>>=
   call phs_fks_generator_test (u, results)
 @
 \subsubsection{FKS regions}
 <<Main: use tests>>=
   use fks_regions_ut, only: fks_regions_test
 <<Main: test cases>>=
   case ("fks_regions")
      call fks_regions_test (u, results)
 <<Main: all tests>>=
   call fks_regions_test (u, results)
 @
 \subsubsection{Real subtraction}
 <<Main: use tests>>=
   use real_subtraction_ut, only: real_subtraction_test
 <<Main: test cases>>=
   case ("real_subtraction")
      call real_subtraction_test (u, results)
 <<Main: all tests>>=
   call real_subtraction_test (u, results)
 @
 \subsubsection{RECOLA}
 <<Main: use tests>>=
   use prc_recola_ut, only: prc_recola_test
 <<Main: test cases>>=
   case ("prc_recola")
      call prc_recola_test (u, results)
 <<Main: all tests>>=
   call prc_recola_test (u, results)
 @
 \subsubsection{RNG Base}
 <<Main: use tests>>=
   use rng_base_ut, only: rng_base_test
 <<Main: test cases>>=
   case ("rng_base")
      call rng_base_test (u, results)
 <<Main: all tests>>=
   call rng_base_test (u, results)
 @
 \subsubsection{RNG Tao}
 <<Main: use tests>>=
   use rng_tao_ut, only: rng_tao_test
 <<Main: test cases>>=
   case ("rng_tao")
      call rng_tao_test (u, results)
 <<Main: all tests>>=
   call rng_tao_test (u, results)
 @
 \subsubsection{RNG Stream}
 <<Main: use tests>>=
   use rng_stream_ut, only: rng_stream_test
 <<Main: test cases>>=
   case ("rng_stream")
      call rng_stream_test (u, results)
 <<Main: all tests>>=
   call rng_stream_test (u, results)
 @
 \subsubsection{Selectors}
 <<Main: use tests>>=
   use selectors_ut, only: selectors_test
 <<Main: test cases>>=
   case ("selectors")
      call selectors_test (u, results)
 <<Main: all tests>>=
   call selectors_test (u, results)
 @
 \subsubsection{VEGAS}
 <<Main: use tests>>=
   use vegas_ut, only: vegas_test
 <<Main: test cases>>=
   case ("vegas")
      call vegas_test (u, results)
 <<Main: all tests>>=
   call vegas_test (u, results)
 @
 \subsubsection{VAMP2}
 <<Main: use tests>>=
   use vamp2_ut, only: vamp2_test
 <<Main: test cases>>=
   case ("vamp2")
      call vamp2_test (u, results)
 <<Main: all tests>>=
   call vamp2_test (u, results)
 @
 \subsubsection{MCI Base}
 <<Main: use tests>>=
   use mci_base_ut, only: mci_base_test
 <<Main: test cases>>=
   case ("mci_base")
      call mci_base_test (u, results)
 <<Main: all tests>>=
   call mci_base_test (u, results)
 @
 \subsubsection{MCI None}
 <<Main: use tests>>=
   use mci_none_ut, only: mci_none_test
 <<Main: test cases>>=
   case ("mci_none")
      call mci_none_test (u, results)
 <<Main: all tests>>=
   call mci_none_test (u, results)
 @
 \subsubsection{MCI Midpoint}
 <<Main: use tests>>=
   use mci_midpoint_ut, only: mci_midpoint_test
 <<Main: test cases>>=
   case ("mci_midpoint")
      call mci_midpoint_test (u, results)
 <<Main: all tests>>=
   call mci_midpoint_test (u, results)
 @
 \subsubsection{MCI VAMP}
 <<Main: use tests>>=
   use mci_vamp_ut, only: mci_vamp_test
 <<Main: test cases>>=
   case ("mci_vamp")
      call mci_vamp_test (u, results)
 <<Main: all tests>>=
   call mci_vamp_test (u, results)
 @
 \subsubsection{MCI VAMP2}
 <<Main: use tests>>=
   use mci_vamp2_ut, only: mci_vamp2_test
 <<Main: test cases>>=
   case ("mci_vamp2")
      call mci_vamp2_test (u, results)
 <<Main: all tests>>=
   call mci_vamp2_test (u, results)
 @
 \subsubsection{Integration Results}
 <<Main: use tests>>=
   use integration_results_ut, only: integration_results_test
 <<Main: test cases>>=
   case ("integration_results")
      call integration_results_test (u, results)
 <<Main: all tests>>=
   call integration_results_test (u, results)
 @
 \subsubsection{PRCLib Interfaces}
 <<Main: use tests>>=
   use prclib_interfaces_ut, only: prclib_interfaces_test
 <<Main: test cases>>=
   case ("prclib_interfaces")
      call prclib_interfaces_test (u, results)
 <<Main: all tests>>=
   call prclib_interfaces_test (u, results)
 @
 \subsubsection{Particle Specifiers}
 <<Main: use tests>>=
   use particle_specifiers_ut, only: particle_specifiers_test
 <<Main: test cases>>=
   case ("particle_specifiers")
      call particle_specifiers_test (u, results)
 <<Main: all tests>>=
   call particle_specifiers_test (u, results)
 @
 \subsubsection{Process Libraries}
 <<Main: use tests>>=
   use process_libraries_ut, only: process_libraries_test
 <<Main: test cases>>=
   case ("process_libraries")
      call process_libraries_test (u, results)
 <<Main: all tests>>=
   call process_libraries_test (u, results)
 @
 \subsubsection{PRCLib Stacks}
 <<Main: use tests>>=
   use prclib_stacks_ut, only: prclib_stacks_test
 <<Main: test cases>>=
   case ("prclib_stacks")
      call prclib_stacks_test (u, results)
 <<Main: all tests>>=
   call prclib_stacks_test (u, results)
 @
 \subsubsection{HepMC}
 <<Main: use tests>>=
   use hepmc_interface_ut, only: hepmc_interface_test
 <<Main: test cases>>=
   case ("hepmc")
      call hepmc_interface_test (u, results)
 <<Main: all tests>>=
   call hepmc_interface_test (u, results)
 @
 \subsubsection{LCIO}
 <<Main: use tests>>=
   use lcio_interface_ut, only: lcio_interface_test
 <<Main: test cases>>=
   case ("lcio")
      call lcio_interface_test (u, results)
 <<Main: all tests>>=
   call lcio_interface_test (u, results)
 @
 \subsubsection{Jets}
 <<Main: use tests>>=
   use jets_ut, only: jets_test
 <<Main: test cases>>=
   case ("jets")
      call jets_test (u, results)
 <<Main: all tests>>=
   call jets_test (u, results)
 @
 \subsection{LHA User Process WHIZARD}
 <<Main: use tests>>=
   use whizard_lha_ut, only: whizard_lha_test
 <<Main: test cases>>=
   case ("whizard_lha")
      call whizard_lha_test (u, results)
 <<Main: all tests>>=
   call whizard_lha_test (u, results)
 @
 \subsection{Pythia8}
 <<Main: use tests>>=
   use pythia8_ut, only: pythia8_test
 <<Main: test cases>>=
   case ("pythia8")
      call pythia8_test (u, results)
 <<Main: all tests>>=
   call pythia8_test (u, results)
 @
 \subsubsection{PDG Arrays}
 <<Main: use tests>>=
   use pdg_arrays_ut, only: pdg_arrays_test
 <<Main: test cases>>=
   case ("pdg_arrays")
      call pdg_arrays_test (u, results)
 <<Main: all tests>>=
   call pdg_arrays_test (u, results)
 @
 \subsubsection{interactions}
 <<Main: use tests>>=
   use interactions_ut, only: interaction_test
 <<Main: test cases>>=
   case ("interactions")
      call interaction_test (u, results)
 <<Main: all tests>>=
   call interaction_test (u, results)
 @
 \subsubsection{SLHA}
 <<Main: use tests>>=
   use slha_interface_ut, only: slha_test
 <<Main: test cases>>=
   case ("slha_interface")
      call slha_test (u, results)
 <<Main: all tests>>=
   call slha_test (u, results)
 @
 \subsubsection{Cascades}
 <<Main: use tests>>=
   use cascades_ut, only: cascades_test
 <<Main: test cases>>=
   case ("cascades")
      call cascades_test (u, results)
 <<Main: all tests>>=
   call cascades_test (u, results)
 @
 \subsubsection{Cascades2 lexer}
 <<Main: use tests>>=
   use cascades2_lexer_ut, only: cascades2_lexer_test
 <<Main: test cases>>=
   case ("cascades2_lexer")
      call cascades2_lexer_test (u, results)
 <<Main: all tests>>=
   call cascades2_lexer_test (u, results)
 @
 \subsubsection{Cascades2}
 <<Main: use tests>>=
   use cascades2_ut, only: cascades2_test
 <<Main: test cases>>=
   case ("cascades2")
      call cascades2_test (u, results)
 <<Main: all tests>>=
   call cascades2_test (u, results)
 @
 \subsubsection{PRC Test}
 <<Main: use tests>>=
   use prc_test_ut, only: prc_test_test
 <<Main: test cases>>=
   case ("prc_test")
      call prc_test_test (u, results)
 <<Main: all tests>>=
   call prc_test_test (u, results)
 @
 \subsubsection{PRC Template ME}
 <<Main: use tests>>=
   use prc_template_me_ut, only: prc_template_me_test
 <<Main: test cases>>=
   case ("prc_template_me")
      call prc_template_me_test (u, results)
 <<Main: all tests>>=
   call prc_template_me_test (u, results)
 @
 \subsubsection{PRC OMega}
 <<Main: use tests>>=
   use prc_omega_ut, only: prc_omega_test
   use prc_omega_ut, only: prc_omega_diags_test
 <<Main: test cases>>=
   case ("prc_omega")
      call prc_omega_test (u, results)
   case ("prc_omega_diags")
      call prc_omega_diags_test (u, results)
 <<Main: all tests>>=
   call prc_omega_test (u, results)
   call prc_omega_diags_test (u, results)
 @
 \subsubsection{Parton States}
 <<Main: use tests>>=
   use parton_states_ut, only: parton_states_test
 <<Main: test cases>>=
   case ("parton_states")
      call parton_states_test (u, results)
 <<Main: all tests>>=
   call parton_states_test (u, results)
 @
 \subsubsection{Subevt Expr}
 <<Main: use tests>>=
   use expr_tests_ut, only: subevt_expr_test
 <<Main: test cases>>=
   case ("subevt_expr")
      call subevt_expr_test (u, results)
 <<Main: all tests>>=
   call subevt_expr_test (u, results)
 @
 \subsubsection{Processes}
 <<Main: use tests>>=
   use processes_ut, only: processes_test
 <<Main: test cases>>=
   case ("processes")
      call processes_test (u, results)
 <<Main: all tests>>=
   call processes_test (u, results)
 @
 \subsubsection{Process Stacks}
 <<Main: use tests>>=
   use process_stacks_ut, only: process_stacks_test
 <<Main: test cases>>=
   case ("process_stacks")
      call process_stacks_test (u, results)
 <<Main: all tests>>=
   call process_stacks_test (u, results)
 @
 \subsubsection{Event Transforms}
 <<Main: use tests>>=
   use event_transforms_ut, only: event_transforms_test
 <<Main: test cases>>=
   case ("event_transforms")
      call event_transforms_test (u, results)
 <<Main: all tests>>=
   call event_transforms_test (u, results)
 @
 \subsubsection{Resonance Insertion Transform}
 <<Main: use tests>>=
   use resonance_insertion_ut, only: resonance_insertion_test
 <<Main: test cases>>=
   case ("resonance_insertion")
      call resonance_insertion_test (u, results)
 <<Main: all tests>>=
   call resonance_insertion_test (u, results)
 @
 \subsubsection{Recoil Kinematics}
 <<Main: use tests>>=
   use recoil_kinematics_ut, only: recoil_kinematics_test
 <<Main: test cases>>=
   case ("recoil_kinematics")
      call recoil_kinematics_test (u, results)
 <<Main: all tests>>=
   call recoil_kinematics_test (u, results)
 @
 \subsubsection{ISR Handler}
 <<Main: use tests>>=
   use isr_epa_handler_ut, only: isr_handler_test
 <<Main: test cases>>=
   case ("isr_handler")
      call isr_handler_test (u, results)
 <<Main: all tests>>=
   call isr_handler_test (u, results)
 @
 \subsubsection{EPA Handler}
 <<Main: use tests>>=
   use isr_epa_handler_ut, only: epa_handler_test
 <<Main: test cases>>=
   case ("epa_handler")
      call epa_handler_test (u, results)
 <<Main: all tests>>=
   call epa_handler_test (u, results)
 @
 \subsubsection{Decays}
 <<Main: use tests>>=
   use decays_ut, only: decays_test
 <<Main: test cases>>=
   case ("decays")
      call decays_test (u, results)
 <<Main: all tests>>=
   call decays_test (u, results)
 @
 \subsubsection{Shower}
 <<Main: use tests>>=
   use shower_ut, only: shower_test
 <<Main: test cases>>=
   case ("shower")
      call shower_test (u, results)
 <<Main: all tests>>=
   call shower_test (u, results)
 @
 \subsubsection{Events}
 <<Main: use tests>>=
   use events_ut, only: events_test
 <<Main: test cases>>=
   case ("events")
      call events_test (u, results)
 <<Main: all tests>>=
   call events_test (u, results)
 @
 \subsubsection{HEP Events}
 <<Main: use tests>>=
   use hep_events_ut, only: hep_events_test
 <<Main: test cases>>=
   case ("hep_events")
      call hep_events_test (u, results)
 <<Main: all tests>>=
   call hep_events_test (u, results)
 @
 \subsubsection{EIO Data}
 <<Main: use tests>>=
   use eio_data_ut, only: eio_data_test
 <<Main: test cases>>=
   case ("eio_data")
      call eio_data_test (u, results)
 <<Main: all tests>>=
   call eio_data_test (u, results)
 @
 \subsubsection{EIO Base}
 <<Main: use tests>>=
   use eio_base_ut, only: eio_base_test
 <<Main: test cases>>=
   case ("eio_base")
      call eio_base_test (u, results)
 <<Main: all tests>>=
   call eio_base_test (u, results)
 @
 \subsubsection{EIO Direct}
 <<Main: use tests>>=
   use eio_direct_ut, only: eio_direct_test
 <<Main: test cases>>=
   case ("eio_direct")
      call eio_direct_test (u, results)
 <<Main: all tests>>=
   call eio_direct_test (u, results)
 @
 \subsubsection{EIO Raw}
 <<Main: use tests>>=
   use eio_raw_ut, only: eio_raw_test
 <<Main: test cases>>=
   case ("eio_raw")
      call eio_raw_test (u, results)
 <<Main: all tests>>=
   call eio_raw_test (u, results)
 @
 \subsubsection{EIO Checkpoints}
 <<Main: use tests>>=
   use eio_checkpoints_ut, only: eio_checkpoints_test
 <<Main: test cases>>=
   case ("eio_checkpoints")
      call eio_checkpoints_test (u, results)
 <<Main: all tests>>=
   call eio_checkpoints_test (u, results)
 @
 \subsubsection{EIO LHEF}
 <<Main: use tests>>=
   use eio_lhef_ut, only: eio_lhef_test
 <<Main: test cases>>=
   case ("eio_lhef")
      call eio_lhef_test (u, results)
 <<Main: all tests>>=
   call eio_lhef_test (u, results)
 @
 \subsubsection{EIO HepMC}
 <<Main: use tests>>=
   use eio_hepmc_ut, only: eio_hepmc_test
 <<Main: test cases>>=
   case ("eio_hepmc")
      call eio_hepmc_test (u, results)
 <<Main: all tests>>=
   call eio_hepmc_test (u, results)
 @
 \subsubsection{EIO LCIO}
 <<Main: use tests>>=
   use eio_lcio_ut, only: eio_lcio_test
 <<Main: test cases>>=
   case ("eio_lcio")
      call eio_lcio_test (u, results)
 <<Main: all tests>>=
   call eio_lcio_test (u, results)
 @
 \subsubsection{EIO StdHEP}
 <<Main: use tests>>=
   use eio_stdhep_ut, only: eio_stdhep_test
 <<Main: test cases>>=
   case ("eio_stdhep")
      call eio_stdhep_test (u, results)
 <<Main: all tests>>=
   call eio_stdhep_test (u, results)
 @
 \subsubsection{EIO ASCII}
 <<Main: use tests>>=
   use eio_ascii_ut, only: eio_ascii_test
 <<Main: test cases>>=
   case ("eio_ascii")
      call eio_ascii_test (u, results)
 <<Main: all tests>>=
   call eio_ascii_test (u, results)
 @
 \subsubsection{EIO Weights}
 <<Main: use tests>>=
   use eio_weights_ut, only: eio_weights_test
 <<Main: test cases>>=
   case ("eio_weights")
      call eio_weights_test (u, results)
 <<Main: all tests>>=
   call eio_weights_test (u, results)
 @
 \subsubsection{EIO Dump}
 <<Main: use tests>>=
   use eio_dump_ut, only: eio_dump_test
 <<Main: test cases>>=
   case ("eio_dump")
      call eio_dump_test (u, results)
 <<Main: all tests>>=
   call eio_dump_test (u, results)
 @
 \subsubsection{Iterations}
 <<Main: use tests>>=
   use iterations_ut, only: iterations_test
 <<Main: test cases>>=
   case ("iterations")
      call iterations_test (u, results)
 <<Main: all tests>>=
   call iterations_test (u, results)
 @
 \subsubsection{Beam Structures}
 <<Main: use tests>>=
   use beam_structures_ut, only: beam_structures_test
 <<Main: test cases>>=
   case ("beam_structures")
      call beam_structures_test (u, results)
 <<Main: all tests>>=
   call beam_structures_test (u, results)
 @
 \subsubsection{RT Data}
 <<Main: use tests>>=
   use rt_data_ut, only: rt_data_test
 <<Main: test cases>>=
   case ("rt_data")
      call rt_data_test (u, results)
 <<Main: all tests>>=
   call rt_data_test (u, results)
 @
 \subsubsection{Dispatch}
 <<Main: use tests>>=
   use dispatch_ut, only: dispatch_test
 <<Main: test cases>>=
   case ("dispatch")
      call dispatch_test (u, results)
 <<Main: all tests>>=
   call dispatch_test (u, results)
 @
 \subsubsection{Dispatch RNG}
 <<Main: use tests>>=
   use dispatch_rng_ut, only: dispatch_rng_test
 <<Main: test cases>>=
   case ("dispatch_rng")
      call dispatch_rng_test (u, results)
 <<Main: all tests>>=
   call dispatch_rng_test (u, results)
 @
 \subsubsection{Dispatch MCI}
 <<Main: use tests>>=
   use dispatch_mci_ut, only: dispatch_mci_test
 <<Main: test cases>>=
   case ("dispatch_mci")
      call dispatch_mci_test (u, results)
 <<Main: all tests>>=
   call dispatch_mci_test (u, results)
 @
 \subsubsection{Dispatch PHS}
 <<Main: use tests>>=
   use dispatch_phs_ut, only: dispatch_phs_test
 <<Main: test cases>>=
   case ("dispatch_phs")
      call dispatch_phs_test (u, results)
 <<Main: all tests>>=
   call dispatch_phs_test (u, results)
 @
 \subsubsection{Dispatch transforms}
 <<Main: use tests>>=
   use dispatch_transforms_ut, only: dispatch_transforms_test
 <<Main: test cases>>=
   case ("dispatch_transforms")
      call dispatch_transforms_test (u, results)
 <<Main: all tests>>=
   call dispatch_transforms_test (u, results)
 @
 \subsubsection{Shower partons}
 <<Main: use tests>>=
   use shower_base_ut, only: shower_base_test
 <<Main: test cases>>=
   case ("shower_base")
      call shower_base_test (u, results)
 <<Main: all tests>>=
   call shower_base_test (u, results)
 @
 \subsubsection{Process Configurations}
 <<Main: use tests>>=
   use process_configurations_ut, only: process_configurations_test
 <<Main: test cases>>=
   case ("process_configurations")
      call process_configurations_test (u, results)
 <<Main: all tests>>=
   call process_configurations_test (u, results)
 @
 \subsubsection{Compilations}
 <<Main: use tests>>=
   use compilations_ut, only: compilations_test
   use compilations_ut, only: compilations_static_test
 <<Main: test cases>>=
   case ("compilations")
      call compilations_test (u, results)
   case ("compilations_static")
      call compilations_static_test (u, results)
 <<Main: all tests>>=
   call compilations_test (u, results)
   call compilations_static_test (u, results)
 @
 \subsubsection{Integrations}
 <<Main: use tests>>=
   use integrations_ut, only: integrations_test
   use integrations_ut, only: integrations_history_test
 <<Main: test cases>>=
   case ("integrations")
      call integrations_test (u, results)
   case ("integrations_history")
      call integrations_history_test (u, results)
 <<Main: all tests>>=
   call integrations_test (u, results)
   call integrations_history_test (u, results)
 @
 \subsubsection{Event Streams}
 <<Main: use tests>>=
   use event_streams_ut, only: event_streams_test
 <<Main: test cases>>=
   case ("event_streams")
      call event_streams_test (u, results)
 <<Main: all tests>>=
   call event_streams_test (u, results)
 @
 \subsubsection{Restricted Subprocesses}
 <<Main: use tests>>=
   use restricted_subprocesses_ut, only: restricted_subprocesses_test
 <<Main: test cases>>=
   case ("restricted_subprocesses")
      call restricted_subprocesses_test (u, results)
 <<Main: all tests>>=
   call restricted_subprocesses_test (u, results)
 @
 \subsubsection{Simulations}
 <<Main: use tests>>=
   use simulations_ut, only: simulations_test
 <<Main: test cases>>=
   case ("simulations")
      call simulations_test (u, results)
 <<Main: all tests>>=
   call simulations_test (u, results)
 @
 \subsubsection{Commands}
 <<Main: use tests>>=
   use commands_ut, only: commands_test
 <<Main: test cases>>=
   case ("commands")
      call commands_test (u, results)
 <<Main: all tests>>=
   call commands_test (u, results)
 @
 \subsubsection{$ttV$ formfactors}
 <<Main: use tests>>=
   use ttv_formfactors_ut, only: ttv_formfactors_test
 <<Main: test cases>>=
   case ("ttv_formfactors")
      call ttv_formfactors_test (u, results)
 <<Main: all tests>>=
   call ttv_formfactors_test (u, results)
 @
 \clearpage
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Whizard-C-Interface}
 <<[[whizard-c-interface.f90]]>>=
 <<File header>>
 
 <<Whizard-C-Interface: Internals>>
 <<Whizard-C-Interface: Init and Finalize>>
 <<Whizard-C-Interface: Interfaced Commads>>
 <<Whizard-C-Interface: HepMC>>
 
 @
 <<Whizard-C-Interface: Internals>>=
   subroutine c_whizard_convert_string (c_string, f_string)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     character(kind=c_char), intent(in) :: c_string(*)
     type(string_t), intent(inout) :: f_string
     character(len=1) :: dummy_char
     integer :: dummy_i = 1
 
     f_string = ""
     do
        if (c_string(dummy_i) == c_null_char) then
           exit
        else if (c_string(dummy_i) == c_new_line) then
           dummy_char = CHAR(13)
           f_string = f_string // dummy_char
           dummy_char = CHAR(10)
        else
           dummy_char = c_string (dummy_i)
        end if
        f_string = f_string // dummy_char
        dummy_i = dummy_i + 1
     end do
     dummy_i = 1
   end subroutine c_whizard_convert_string
 
   subroutine c_whizard_commands (w_c_instance, cmds)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
     use commands
     use diagnostics
     use lexers
     use models
     use parser
     use whizard
 
     type(c_ptr), intent(inout) :: w_c_instance
     type(whizard_t), pointer :: whizard_instance
     type(string_t) :: cmds
     type(parse_tree_t) :: parse_tree
     type(parse_node_t), pointer :: pn_root
     type(stream_t), target :: stream
     type(lexer_t) :: lexer
     type(command_list_t), target :: cmd_list
 
     call c_f_pointer (w_c_instance, whizard_instance)
     call lexer_init_cmd_list (lexer)
     call syntax_cmd_list_init ()
 
     call stream_init (stream, cmds)
     call lexer_assign_stream (lexer, stream)
     call parse_tree_init (parse_tree, syntax_cmd_list, lexer)
     pn_root => parse_tree%get_root_ptr ()
 
     if (associated (pn_root)) then
        call cmd_list%compile (pn_root, whizard_instance%global)
     end if
     call whizard_instance%global%activate ()
     call cmd_list%execute (whizard_instance%global)
     call cmd_list%final ()
 
     call parse_tree_final (parse_tree)
     call stream_final (stream)
     call lexer_final (lexer)
     call syntax_cmd_list_final ()
   end subroutine c_whizard_commands
 
 @
 <<Whizard-C-Interface: Init and Finalize>>=
   subroutine c_whizard_init (w_c_instance) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
     use system_dependencies
     use diagnostics
     use ifiles
     use os_interface
     use whizard
 
     implicit none
 
   <<Main: cmdline arg len declaration>>
 
     type(c_ptr), intent(out) :: w_c_instance
     logical :: banner
     type(string_t) :: files, model, default_lib, library, libraries
 !     type(string_t) :: check, checks
     type(string_t) :: logfile
     type(string_t) :: user_src, user_lib
     type(paths_t) :: paths
     logical :: rebuild_library, rebuild_user
     logical :: rebuild_phs, rebuild_grids, rebuild_events
 
     type(whizard_options_t), allocatable :: options
     type(whizard_t), pointer :: whizard_instance
 
 
     ! Initial values
     files = ""
     model = "SM"
     default_lib = "default_lib"
     library = ""
     libraries = ""
     banner = .true.
     logging = .true.
     logfile = "whizard.log"
 !     check = ""
 !     checks = ""
     user_src = ""
     user_lib = ""
     rebuild_library = .false.
     rebuild_user = .false.
     rebuild_phs = .false.
     rebuild_grids = .false.
     rebuild_events = .false.
     call paths_init (paths)
 
     ! Overall initialization
     if (logfile /= "")  call logfile_init (logfile)
     call mask_term_signals ()
     if (banner)  call msg_banner ()
 
     ! Set options and initialize the whizard object
     allocate (options)
     options%preload_model = model
     options%default_lib = default_lib
     options%preload_libraries = libraries
     options%rebuild_library = rebuild_library
     options%rebuild_user = rebuild_user
     options%rebuild_phs = rebuild_phs
     options%rebuild_grids = rebuild_grids
     options%rebuild_events = rebuild_events
 
     allocate (whizard_instance)
     call whizard_instance%init (options, paths)
 
 !     if (checks /= "") then
 !        checks = trim (adjustl (checks))
 !        RUN_CHECKS: do while (checks /= "")
 !           call split (checks, check, " ")
 !           call whizard_check (check, test_results)
 !        end do RUN_CHECKS
 !        call test_results%wrapup (6, success)
 !        if (.not. success)  quit_code = 7
 !        quit = .true.
 !     end if
 
     w_c_instance = c_loc (whizard_instance)
 
   end subroutine c_whizard_init
 
   subroutine c_whizard_finalize (w_c_instance) bind(C)
     use, intrinsic :: iso_c_binding
     use system_dependencies
     use diagnostics
     use ifiles
     use os_interface
     use whizard
 
     type(c_ptr), intent(in) :: w_c_instance
     type(whizard_t), pointer :: whizard_instance
     integer :: quit_code = 0
 
     call c_f_pointer (w_c_instance, whizard_instance)
     call whizard_instance%final ()
     deallocate (whizard_instance)
     call terminate_now_if_signal ()
     call release_term_signals ()
     call msg_terminate (quit_code = quit_code)
   end subroutine c_whizard_finalize
 
   subroutine c_whizard_process_string (w_c_instance, c_cmds_in) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     character(kind=c_char) :: c_cmds_in(*)
     type(string_t) :: f_cmds
 
     call c_whizard_convert_string (c_cmds_in, f_cmds)
     call c_whizard_commands (w_c_instance, f_cmds)
   end subroutine c_whizard_process_string
 
 @
 <<Whizard-C-Interface: Interfaced Commads>>=
   subroutine c_whizard_model (w_c_instance, c_model) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     character(kind=c_char) :: c_model(*)
     type(string_t) :: model, mdl_str
 
     call c_whizard_convert_string (c_model, model)
     mdl_str = "model = " // model
     call c_whizard_commands (w_c_instance, mdl_str)
   end subroutine c_whizard_model
 
   subroutine c_whizard_library (w_c_instance, c_library) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     character(kind=c_char) :: c_library(*)
     type(string_t) :: library, lib_str
 
     call c_whizard_convert_string(c_library, library)
     lib_str = "library = " // library
     call c_whizard_commands (w_c_instance, lib_str)
   end subroutine c_whizard_library
 
   subroutine c_whizard_process (w_c_instance, c_id, c_in, c_out) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     character(kind=c_char) :: c_id(*), c_in(*), c_out(*)
     type(string_t) :: proc_str, id, in, out
 
     call c_whizard_convert_string (c_id, id)
     call c_whizard_convert_string (c_in, in)
     call c_whizard_convert_string (c_out, out)
     proc_str = "process " // id // " = " // in // " => " // out
     call c_whizard_commands (w_c_instance, proc_str)
   end subroutine c_whizard_process
 
   subroutine c_whizard_compile (w_c_instance) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     type(c_ptr), intent(inout) :: w_c_instance
     type(string_t) :: cmp_str
     cmp_str = "compile"
     call c_whizard_commands (w_c_instance, cmp_str)
   end subroutine c_whizard_compile
 
   subroutine c_whizard_beams (w_c_instance, c_specs) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     character(kind=c_char) :: c_specs(*)
     type(string_t) :: specs, beam_str
 
     call c_whizard_convert_string (c_specs, specs)
     beam_str = "beams = " // specs
     call c_whizard_commands (w_c_instance, beam_str)
   end subroutine c_whizard_beams
 
   subroutine c_whizard_integrate (w_c_instance, c_process) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     character(kind=c_char) :: c_process(*)
     type(string_t) :: process, int_str
 
     call c_whizard_convert_string (c_process, process)
     int_str = "integrate (" // process //")"
     call c_whizard_commands (w_c_instance, int_str)
   end subroutine c_whizard_integrate
 
   subroutine c_whizard_matrix_element_test &
        (w_c_instance, c_process, n_calls) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     integer(kind=c_int) :: n_calls
     character(kind=c_char) :: c_process(*)
     type(string_t) :: process, me_str
     character(len=8) :: buffer
 
     call c_whizard_convert_string (c_process, process)
     write (buffer, "(I0)")  n_calls
     me_str = "integrate (" // process // ") { ?phs_only = true" // &
          "  n_calls_test = " // trim (buffer)
     call c_whizard_commands (w_c_instance, me_str)
   end subroutine c_whizard_matrix_element_test
 
   subroutine c_whizard_simulate (w_c_instance, c_id) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     character(kind=c_char) :: c_id(*)
     type(string_t) :: sim_str, id
 
     call c_whizard_convert_string(c_id, id)
     sim_str = "simulate (" // id // ")"
     call c_whizard_commands (w_c_instance, sim_str)
   end subroutine c_whizard_simulate
 
   subroutine c_whizard_sqrts (w_c_instance, c_value, c_unit) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     character(kind=c_char) :: c_unit(*)
     integer(kind=c_int) :: c_value
     integer :: f_value
     character(len=8) :: f_val
     type(string_t) :: val, unit, sqrts_str
 
     f_value = c_value
     write (f_val,'(i8)') f_value
     val = f_val
     call c_whizard_convert_string (c_unit, unit)
     sqrts_str = "sqrts =" // val // unit
     call c_whizard_commands (w_c_instance, sqrts_str)
   end subroutine c_whizard_sqrts
 
 @
 <<Whizard-C-Interface: HepMC>>=
   type(c_ptr) function c_whizard_hepmc_test &
        (w_c_instance, c_id, c_proc_id, c_event_id) bind(C)
     use, intrinsic :: iso_c_binding
     use iso_varying_string, string_t => varying_string !NODEP!
     use commands
     use diagnostics
     use events
     use hepmc_interface
     use lexers
     use models
     use parser
     use instances
     use rt_data
     use simulations
     use whizard
     use os_interface
 
     implicit none
 
     type(c_ptr), intent(inout) :: w_c_instance
     type(string_t) :: sim_str
     type(parse_tree_t) :: parse_tree
     type(parse_node_t), pointer :: pn_root
     type(stream_t), target :: stream
     type(lexer_t) :: lexer
     type(command_list_t), pointer :: cmd_list
     type(whizard_t), pointer :: whizard_instance
 
     type(simulation_t), target :: sim
 
     character(kind=c_char), intent(in) :: c_id(*)
     type(string_t) :: id
     integer(kind=c_int), value :: c_proc_id, c_event_id
     integer :: proc_id
 
     type(hepmc_event_t), pointer :: hepmc_event
 
     call c_f_pointer (w_c_instance, whizard_instance)
 
     call c_whizard_convert_string (c_id, id)
     sim_str = "simulate (" // id // ")"
 
     proc_id = c_proc_id
 
     allocate (hepmc_event)
     call hepmc_event_init (hepmc_event, c_proc_id, c_event_id)
 
     call syntax_cmd_list_init ()
     call lexer_init_cmd_list (lexer)
 
     call stream_init (stream, sim_str)
     call lexer_assign_stream (lexer, stream)
     call parse_tree_init (parse_tree, syntax_cmd_list, lexer)
     pn_root => parse_tree%get_root_ptr ()
 
     allocate (cmd_list)
     if (associated (pn_root)) then
        call cmd_list%compile (pn_root, whizard_instance%global)
     end if
 
     call sim%init ([id], .true., .true., whizard_instance%global)
 
     !!! This should generate a HepMC event as hepmc_event_t type
     call msg_message ("Not enabled for the moment.")
 
     call sim%final ()
 
     call cmd_list%final ()
 
     call parse_tree_final (parse_tree)
     call stream_final (stream)
     call lexer_final (lexer)
     call syntax_cmd_list_final ()
 
     c_whizard_hepmc_test = c_loc(hepmc_event)
     return
   end function c_whizard_hepmc_test
 @ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Index: trunk/share/tests/Makefile.am
===================================================================
--- trunk/share/tests/Makefile.am	(revision 8346)
+++ trunk/share/tests/Makefile.am	(revision 8347)
@@ -1,1448 +1,1452 @@
 ## Makefile.am -- Makefile for WHIZARD tests
 ##
 ## Process this file with automake to produce Makefile.in
 ##
 ########################################################################
 #
 # Copyright (C) 1999-2019 by
 #     Wolfgang Kilian <kilian@physik.uni-siegen.de>
 #     Thorsten Ohl <ohl@physik.uni-wuerzburg.de>
 #     Juergen Reuter <juergen.reuter@desy.de>
 #     with contributions from
 #     cf. main AUTHORS file
 #
 # WHIZARD is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 2, or (at your option)
 # any later version.
 #
 # WHIZARD is distributed in the hope that it will be useful, but
 # WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 #
 ########################################################################
 
 EXTRA_DIST = \
     $(TESTSUITE_MACROS) $(TESTSUITES_M4) $(TESTSUITES_SIN) \
     $(TESTSUITE_TOOLS) \
     $(REF_OUTPUT_FILES) \
     cascades2_lexer_1.fds \
     cascades2_1.fds \
     cascades2_2.fds \
     functional_tests/structure_2_inc.sin functional_tests/testproc_3.phs \
     functional_tests/user_cuts.f90 \
     functional_tests/susyhit.in \
     ext_tests_nmssm/nmssm.slha
 
 TESTSUITE_MACROS = testsuite.m4
 TESTSUITE_TOOLS = \
     check-debug-output.py \
     check-debug-output-hadro.py \
     check-hepmc-weights.py \
     compare-integrals.py \
     compare-integrals-multi.py \
     compare-methods.py \
     compare-histograms.py
 
 REF_OUTPUT_FILES = \
     extra_integration_results.dat \
     $(REF_OUTPUT_FILES_BASE) $(REF_OUTPUT_FILES_DOUBLE) \
     $(REF_OUTPUT_FILES_PREC) $(REF_OUTPUT_FILES_EXT) \
     $(REF_OUTPUT_FILES_QUAD)
 
 REF_OUTPUT_FILES_BASE = \
     unit_tests/ref-output/analysis_1.ref \
     unit_tests/ref-output/pdg_arrays_1.ref \
     unit_tests/ref-output/pdg_arrays_2.ref \
     unit_tests/ref-output/pdg_arrays_3.ref \
     unit_tests/ref-output/pdg_arrays_4.ref \
     unit_tests/ref-output/pdg_arrays_5.ref \
     unit_tests/ref-output/expressions_1.ref \
     unit_tests/ref-output/expressions_2.ref \
     unit_tests/ref-output/expressions_3.ref \
     unit_tests/ref-output/expressions_4.ref \
     unit_tests/ref-output/su_algebra_1.ref \
     unit_tests/ref-output/su_algebra_2.ref \
     unit_tests/ref-output/su_algebra_3.ref \
     unit_tests/ref-output/su_algebra_4.ref \
     unit_tests/ref-output/bloch_vectors_1.ref \
     unit_tests/ref-output/bloch_vectors_2.ref \
     unit_tests/ref-output/bloch_vectors_3.ref \
     unit_tests/ref-output/bloch_vectors_4.ref \
     unit_tests/ref-output/bloch_vectors_5.ref \
     unit_tests/ref-output/bloch_vectors_6.ref \
     unit_tests/ref-output/bloch_vectors_7.ref \
     unit_tests/ref-output/polarization_1.ref \
     unit_tests/ref-output/polarization_2.ref \
     unit_tests/ref-output/beam_1.ref \
     unit_tests/ref-output/beam_2.ref \
     unit_tests/ref-output/beam_3.ref \
     unit_tests/ref-output/md5_1.ref \
     unit_tests/ref-output/cputime_1.ref \
     unit_tests/ref-output/cputime_2.ref \
     unit_tests/ref-output/lexer_1.ref \
     unit_tests/ref-output/parse_1.ref \
     unit_tests/ref-output/color_1.ref \
     unit_tests/ref-output/color_2.ref \
     unit_tests/ref-output/os_interface_1.ref \
     unit_tests/ref-output/evaluator_1.ref \
     unit_tests/ref-output/evaluator_2.ref \
     unit_tests/ref-output/evaluator_3.ref \
     unit_tests/ref-output/evaluator_4.ref \
     unit_tests/ref-output/format_1.ref \
     unit_tests/ref-output/sorting_1.ref \
     unit_tests/ref-output/grids_1.ref \
     unit_tests/ref-output/grids_2.ref \
     unit_tests/ref-output/grids_3.ref \
     unit_tests/ref-output/grids_4.ref \
     unit_tests/ref-output/grids_5.ref \
     unit_tests/ref-output/solver_1.ref \
     unit_tests/ref-output/state_matrix_1.ref \
     unit_tests/ref-output/state_matrix_2.ref \
     unit_tests/ref-output/state_matrix_3.ref \
     unit_tests/ref-output/state_matrix_4.ref \
     unit_tests/ref-output/state_matrix_5.ref \
     unit_tests/ref-output/state_matrix_6.ref \
     unit_tests/ref-output/state_matrix_7.ref \
     unit_tests/ref-output/interaction_1.ref \
     unit_tests/ref-output/xml_1.ref \
     unit_tests/ref-output/xml_2.ref \
     unit_tests/ref-output/xml_3.ref \
     unit_tests/ref-output/xml_4.ref \
     unit_tests/ref-output/sm_qcd_1.ref \
     unit_tests/ref-output/sm_physics_1.ref \
     unit_tests/ref-output/sm_physics_2.ref \
     unit_tests/ref-output/models_1.ref \
     unit_tests/ref-output/models_2.ref \
     unit_tests/ref-output/models_3.ref \
     unit_tests/ref-output/models_4.ref \
     unit_tests/ref-output/models_5.ref \
     unit_tests/ref-output/models_6.ref \
     unit_tests/ref-output/models_7.ref \
     unit_tests/ref-output/models_8.ref \
     unit_tests/ref-output/models_9.ref \
     unit_tests/ref-output/auto_components_1.ref \
     unit_tests/ref-output/auto_components_2.ref \
     unit_tests/ref-output/auto_components_3.ref \
     unit_tests/ref-output/radiation_generator_1.ref \
     unit_tests/ref-output/radiation_generator_2.ref \
     unit_tests/ref-output/radiation_generator_3.ref \
     unit_tests/ref-output/radiation_generator_4.ref \
     unit_tests/ref-output/particles_1.ref \
     unit_tests/ref-output/particles_2.ref \
     unit_tests/ref-output/particles_3.ref \
     unit_tests/ref-output/particles_4.ref \
     unit_tests/ref-output/particles_5.ref \
     unit_tests/ref-output/particles_6.ref \
     unit_tests/ref-output/particles_7.ref \
     unit_tests/ref-output/particles_8.ref \
     unit_tests/ref-output/particles_9.ref \
     unit_tests/ref-output/beam_structures_1.ref \
     unit_tests/ref-output/beam_structures_2.ref \
     unit_tests/ref-output/beam_structures_3.ref \
     unit_tests/ref-output/beam_structures_4.ref \
     unit_tests/ref-output/beam_structures_5.ref \
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     unit_tests/ref-output/commands_28.ref \
     unit_tests/ref-output/commands_29.ref \
     unit_tests/ref-output/commands_30.ref \
     unit_tests/ref-output/commands_31.ref \
     unit_tests/ref-output/commands_32.ref \
     unit_tests/ref-output/commands_33.ref \
     unit_tests/ref-output/commands_34.ref \
     unit_tests/ref-output/jets_1.ref \
     unit_tests/ref-output/hepmc2_interface_1.ref \
     unit_tests/ref-output/hepmc3_interface_1.ref \
     unit_tests/ref-output/lcio_interface_1.ref \
     unit_tests/ref-output/ttv_formfactors_1.ref \
     unit_tests/ref-output/ttv_formfactors_2.ref \
     unit_tests/ref-output/blha_1.ref \
     unit_tests/ref-output/blha_2.ref \
     unit_tests/ref-output/blha_3.ref \
     unit_tests/ref-output/whizard_lha_1.ref \
     functional_tests/ref-output/pack_1.ref \
     functional_tests/ref-output/structure_1.ref \
     functional_tests/ref-output/structure_2.ref \
     functional_tests/ref-output/structure_3.ref \
     functional_tests/ref-output/structure_4.ref \
     functional_tests/ref-output/structure_5.ref \
     functional_tests/ref-output/structure_6.ref \
     functional_tests/ref-output/structure_7.ref \
     functional_tests/ref-output/structure_8.ref \
     functional_tests/ref-output/vars.ref \
     functional_tests/ref-output/extpar.ref \
     functional_tests/ref-output/testproc_1.ref \
     functional_tests/ref-output/testproc_2.ref \
     functional_tests/ref-output/testproc_3.ref \
     functional_tests/ref-output/testproc_4.ref \
     functional_tests/ref-output/testproc_5.ref \
     functional_tests/ref-output/testproc_6.ref \
     functional_tests/ref-output/testproc_7.ref \
     functional_tests/ref-output/testproc_8.ref \
     functional_tests/ref-output/testproc_9.ref \
     functional_tests/ref-output/testproc_10.ref \
     functional_tests/ref-output/testproc_11.ref \
     functional_tests/ref-output/testproc_12.ref \
     functional_tests/ref-output/template_me_1.ref \
     functional_tests/ref-output/template_me_2.ref \
     functional_tests/ref-output/susyhit.ref \
     functional_tests/ref-output/restrictions.ref \
     functional_tests/ref-output/process_log.ref \
     functional_tests/ref-output/static_1.ref \
     functional_tests/ref-output/static_2.ref \
     functional_tests/ref-output/libraries_1.ref \
     functional_tests/ref-output/libraries_2.ref \
     functional_tests/ref-output/libraries_4.ref \
     functional_tests/ref-output/job_id_1.ref \
     functional_tests/ref-output/job_id_2.ref \
     functional_tests/ref-output/job_id_3.ref \
     functional_tests/ref-output/job_id_4.ref \
     functional_tests/ref-output/rebuild_2.ref \
     functional_tests/ref-output/rebuild_3.ref \
     functional_tests/ref-output/rebuild_4.ref \
     functional_tests/ref-output/fatal.ref \
+    functional_tests/ref-output/cmdline_1.ref \
     functional_tests/ref-output/model_change_1.ref \
     functional_tests/ref-output/model_change_2.ref \
     functional_tests/ref-output/model_change_3.ref \
     functional_tests/ref-output/model_scheme_1.ref \
     functional_tests/ref-output/model_test.ref \
     functional_tests/ref-output/cuts.ref \
     functional_tests/ref-output/user_cuts.ref \
     functional_tests/ref-output/user_prc_threshold_1.ref \
     functional_tests/ref-output/user_prc_threshold_2.ref \
     functional_tests/ref-output/qedtest_1.ref \
     functional_tests/ref-output/qedtest_2.ref \
     functional_tests/ref-output/qedtest_5.ref \
     functional_tests/ref-output/qedtest_6.ref \
     functional_tests/ref-output/qedtest_7.ref \
     functional_tests/ref-output/qedtest_8.ref \
     functional_tests/ref-output/qedtest_9.ref \
     functional_tests/ref-output/qedtest_10.ref \
     functional_tests/ref-output/qcdtest_4.ref \
     functional_tests/ref-output/qcdtest_5.ref \
     functional_tests/ref-output/qcdtest_6.ref \
     functional_tests/ref-output/rambo_vamp_1.ref \
     functional_tests/ref-output/rambo_vamp_2.ref \
     functional_tests/ref-output/beam_setup_1.ref \
     functional_tests/ref-output/beam_setup_2.ref \
     functional_tests/ref-output/beam_setup_3.ref \
     functional_tests/ref-output/beam_setup_4.ref \
     functional_tests/ref-output/observables_1.ref \
     functional_tests/ref-output/event_weights_1.ref \
     functional_tests/ref-output/event_weights_2.ref \
     functional_tests/ref-output/event_eff_1.ref \
     functional_tests/ref-output/event_eff_2.ref \
     functional_tests/ref-output/event_dump_1.ref \
     functional_tests/ref-output/event_dump_2.ref \
     functional_tests/ref-output/reweight_1.ref \
     functional_tests/ref-output/reweight_2.ref \
     functional_tests/ref-output/reweight_3.ref \
     functional_tests/ref-output/reweight_4.ref \
     functional_tests/ref-output/reweight_5.ref \
     functional_tests/ref-output/reweight_6.ref \
     functional_tests/ref-output/reweight_7.ref \
     functional_tests/ref-output/reweight_8.ref \
     functional_tests/ref-output/analyze_1.ref \
     functional_tests/ref-output/analyze_2.ref \
     functional_tests/ref-output/analyze_3.ref \
     functional_tests/ref-output/analyze_4.ref \
     functional_tests/ref-output/analyze_5.ref \
     functional_tests/ref-output/analyze_6.ref \
     functional_tests/ref-output/bjet_cluster.ref \
     functional_tests/ref-output/colors.ref \
     functional_tests/ref-output/colors_hgg.ref \
     functional_tests/ref-output/alphas.ref \
     functional_tests/ref-output/jets_xsec.ref \
     functional_tests/ref-output/shower_err_1.ref \
     functional_tests/ref-output/parton_shower_1.ref \
     functional_tests/ref-output/pythia6_1.ref \
     functional_tests/ref-output/pythia6_2.ref \
     functional_tests/ref-output/hadronize_1.ref \
     functional_tests/ref-output/mlm_matching_fsr.ref \
     functional_tests/ref-output/mlm_pythia6_isr.ref \
     functional_tests/ref-output/hepmc_1.ref \
     functional_tests/ref-output/hepmc_2.ref \
     functional_tests/ref-output/hepmc_3.ref \
     functional_tests/ref-output/hepmc_4.ref \
     functional_tests/ref-output/hepmc_5.ref \
     functional_tests/ref-output/hepmc_6.ref \
     functional_tests/ref-output/hepmc_7.ref \
     functional_tests/ref-output/hepmc_9.ref \
     functional_tests/ref-output/hepmc_10.ref \
     functional_tests/ref-output/lhef_1.ref \
     functional_tests/ref-output/lhef_2.ref \
     functional_tests/ref-output/lhef_3.ref \
     functional_tests/ref-output/lhef_4.ref \
     functional_tests/ref-output/lhef_5.ref \
     functional_tests/ref-output/lhef_6.ref \
     functional_tests/ref-output/lhef_9.ref \
     functional_tests/ref-output/lhef_10.ref \
     functional_tests/ref-output/lhef_11.ref \
     functional_tests/ref-output/select_1.ref \
     functional_tests/ref-output/select_2.ref \
     functional_tests/ref-output/stdhep_1.ref \
     functional_tests/ref-output/stdhep_2.ref \
     functional_tests/ref-output/stdhep_3.ref \
     functional_tests/ref-output/stdhep_4.ref \
     functional_tests/ref-output/stdhep_5.ref \
     functional_tests/ref-output/stdhep_6.ref \
     functional_tests/ref-output/lcio_1.ref \
     functional_tests/ref-output/lcio_3.ref \
     functional_tests/ref-output/lcio_4.ref \
     functional_tests/ref-output/lcio_5.ref \
     functional_tests/ref-output/lcio_6.ref \
     functional_tests/ref-output/lcio_8.ref \
     functional_tests/ref-output/lcio_9.ref \
     functional_tests/ref-output/lcio_10.ref \
     functional_tests/ref-output/fatal_beam_decay.ref \
     functional_tests/ref-output/smtest_1.ref \
     functional_tests/ref-output/smtest_3.ref \
     functional_tests/ref-output/smtest_4.ref \
     functional_tests/ref-output/smtest_5.ref \
     functional_tests/ref-output/smtest_6.ref \
     functional_tests/ref-output/smtest_7.ref \
     functional_tests/ref-output/smtest_9.ref \
     functional_tests/ref-output/smtest_10.ref \
     functional_tests/ref-output/smtest_11.ref \
     functional_tests/ref-output/smtest_12.ref \
     functional_tests/ref-output/smtest_13.ref \
     functional_tests/ref-output/smtest_14.ref \
     functional_tests/ref-output/smtest_15.ref \
     functional_tests/ref-output/smtest_16.ref \
     functional_tests/ref-output/photon_isolation_1.ref \
     functional_tests/ref-output/photon_isolation_2.ref \
     functional_tests/ref-output/sm_cms_1.ref \
     functional_tests/ref-output/resonances_5.ref \
     functional_tests/ref-output/resonances_6.ref \
     functional_tests/ref-output/resonances_7.ref \
     functional_tests/ref-output/resonances_8.ref \
     functional_tests/ref-output/resonances_9.ref \
     functional_tests/ref-output/resonances_12.ref \
     functional_tests/ref-output/ufo_1.ref \
     functional_tests/ref-output/ufo_2.ref \
     functional_tests/ref-output/ufo_3.ref \
     functional_tests/ref-output/ufo_4.ref \
     functional_tests/ref-output/nlo_1.ref \
     functional_tests/ref-output/nlo_2.ref \
     functional_tests/ref-output/nlo_6.ref \
     functional_tests/ref-output/real_partition_1.ref \
     functional_tests/ref-output/fks_res_2.ref \
     functional_tests/ref-output/openloops_1.ref \
     functional_tests/ref-output/openloops_2.ref \
     functional_tests/ref-output/openloops_4.ref \
     functional_tests/ref-output/openloops_5.ref \
     functional_tests/ref-output/openloops_6.ref \
     functional_tests/ref-output/openloops_7.ref \
     functional_tests/ref-output/openloops_8.ref \
     functional_tests/ref-output/openloops_9.ref \
     functional_tests/ref-output/openloops_10.ref \
     functional_tests/ref-output/openloops_11.ref \
     functional_tests/ref-output/openloops_12.ref \
     functional_tests/ref-output/openloops_13.ref \
     functional_tests/ref-output/recola_1.ref \
     functional_tests/ref-output/recola_2.ref \
     functional_tests/ref-output/recola_3.ref \
     functional_tests/ref-output/recola_4.ref \
     functional_tests/ref-output/recola_5.ref \
     functional_tests/ref-output/recola_6.ref \
     functional_tests/ref-output/recola_7.ref \
     functional_tests/ref-output/recola_8.ref \
     functional_tests/ref-output/nlo_decay_1.ref \
     functional_tests/ref-output/mssmtest_1.ref \
     functional_tests/ref-output/mssmtest_2.ref \
     functional_tests/ref-output/mssmtest_3.ref \
     functional_tests/ref-output/spincor_1.ref \
     functional_tests/ref-output/show_1.ref \
     functional_tests/ref-output/show_2.ref \
     functional_tests/ref-output/show_3.ref \
     functional_tests/ref-output/show_4.ref \
     functional_tests/ref-output/show_5.ref \
     functional_tests/ref-output/method_ovm_1.ref \
     functional_tests/ref-output/multi_comp_4.ref \
     functional_tests/ref-output/flvsum_1.ref \
     functional_tests/ref-output/br_redef_1.ref \
     functional_tests/ref-output/decay_err_1.ref \
     functional_tests/ref-output/decay_err_2.ref \
     functional_tests/ref-output/decay_err_3.ref \
     functional_tests/ref-output/polarized_1.ref \
     functional_tests/ref-output/circe1_1.ref \
     functional_tests/ref-output/circe1_2.ref \
     functional_tests/ref-output/circe1_3.ref \
     functional_tests/ref-output/circe1_6.ref \
     functional_tests/ref-output/circe1_10.ref \
     functional_tests/ref-output/circe1_errors_1.ref \
     functional_tests/ref-output/circe2_1.ref \
     functional_tests/ref-output/circe2_2.ref \
     functional_tests/ref-output/circe2_3.ref \
     functional_tests/ref-output/isr_1.ref \
     functional_tests/ref-output/epa_1.ref \
     functional_tests/ref-output/epa_2.ref \
     functional_tests/ref-output/isr_epa_1.ref \
     functional_tests/ref-output/ep_3.ref \
     functional_tests/ref-output/ewa_4.ref \
     functional_tests/ref-output/gaussian_1.ref \
     functional_tests/ref-output/gaussian_2.ref \
     functional_tests/ref-output/beam_events_1.ref \
     functional_tests/ref-output/beam_events_4.ref \
     functional_tests/ref-output/energy_scan_1.ref \
     functional_tests/ref-output/cascades2_phs_1.ref \
     functional_tests/ref-output/vamp2_1.ref \
     functional_tests/ref-output/vamp2_2.ref \
     ext_tests_nlo/ref-output/nlo_ee4j.ref \
     ext_tests_nlo/ref-output/nlo_ee4t.ref \
     ext_tests_nlo/ref-output/nlo_ee5j.ref \
     ext_tests_nlo/ref-output/nlo_eejj.ref \
     ext_tests_nlo/ref-output/nlo_eejjj.ref \
     ext_tests_nlo/ref-output/nlo_eett.ref \
     ext_tests_nlo/ref-output/nlo_eetth.ref \
     ext_tests_nlo/ref-output/nlo_eetthh.ref \
     ext_tests_nlo/ref-output/nlo_eetthj.ref \
     ext_tests_nlo/ref-output/nlo_eetthz.ref \
     ext_tests_nlo/ref-output/nlo_eettwjj.ref \
     ext_tests_nlo/ref-output/nlo_eettww.ref \
     ext_tests_nlo/ref-output/nlo_eettz.ref \
     ext_tests_nlo/ref-output/nlo_eettzj.ref \
     ext_tests_nlo/ref-output/nlo_eettzjj.ref \
     ext_tests_nlo/ref-output/nlo_eettzz.ref \
     ext_tests_nlo/ref-output/nlo_pptttt.ref \
     ext_tests_nlo/ref-output/nlo_ppzw.ref \
     ext_tests_nlo/ref-output/nlo_ppzz.ref
 
 # Reference files that depend on the numerical precision
 REF_OUTPUT_FILES_DOUBLE = \
     functional_tests/ref-output-double/qedtest_3.ref \
     functional_tests/ref-output-double/qedtest_4.ref \
     functional_tests/ref-output-double/qcdtest_1.ref \
     functional_tests/ref-output-double/qcdtest_2.ref \
     functional_tests/ref-output-double/qcdtest_3.ref \
     functional_tests/ref-output-double/smtest_2.ref \
     functional_tests/ref-output-double/smtest_8.ref \
     functional_tests/ref-output-double/observables_2.ref \
     functional_tests/ref-output-double/colors_2.ref \
     functional_tests/ref-output-double/resonances_1.ref \
     functional_tests/ref-output-double/resonances_2.ref \
     functional_tests/ref-output-double/resonances_3.ref \
     functional_tests/ref-output-double/resonances_4.ref \
     functional_tests/ref-output-double/resonances_10.ref \
     functional_tests/ref-output-double/resonances_11.ref \
     functional_tests/ref-output-double/beam_setup_5.ref \
     functional_tests/ref-output-double/nlo_3.ref \
     functional_tests/ref-output-double/nlo_4.ref \
     functional_tests/ref-output-double/nlo_5.ref \
     functional_tests/ref-output-double/fks_res_1.ref \
     functional_tests/ref-output-double/fks_res_3.ref \
     functional_tests/ref-output-double/openloops_3.ref \
     functional_tests/ref-output-double/powheg_1.ref \
     functional_tests/ref-output-double/defaultcuts.ref \
     functional_tests/ref-output-double/parton_shower_2.ref \
     functional_tests/ref-output-double/helicity.ref \
     functional_tests/ref-output-double/lhef_7.ref \
     functional_tests/ref-output-double/hepmc_8.ref \
     functional_tests/ref-output-double/lcio_2.ref \
     functional_tests/ref-output-double/lcio_7.ref \
     functional_tests/ref-output-double/multi_comp_1.ref \
     functional_tests/ref-output-double/multi_comp_2.ref \
     functional_tests/ref-output-double/multi_comp_3.ref \
     functional_tests/ref-output-double/pdf_builtin.ref \
     functional_tests/ref-output-double/lhapdf5.ref \
     functional_tests/ref-output-double/lhapdf6.ref \
     functional_tests/ref-output-double/ep_1.ref \
     functional_tests/ref-output-double/ep_2.ref \
     functional_tests/ref-output-double/circe1_4.ref \
     functional_tests/ref-output-double/circe1_5.ref \
     functional_tests/ref-output-double/circe1_7.ref \
     functional_tests/ref-output-double/circe1_8.ref \
     functional_tests/ref-output-double/circe1_9.ref \
     functional_tests/ref-output-double/circe1_photons_1.ref \
     functional_tests/ref-output-double/circe1_photons_2.ref \
     functional_tests/ref-output-double/circe1_photons_3.ref \
     functional_tests/ref-output-double/circe1_photons_4.ref \
     functional_tests/ref-output-double/circe1_photons_5.ref \
     functional_tests/ref-output-double/isr_2.ref \
     functional_tests/ref-output-double/isr_3.ref \
     functional_tests/ref-output-double/isr_4.ref \
     functional_tests/ref-output-double/isr_5.ref \
     functional_tests/ref-output-double/pythia6_3.ref \
     functional_tests/ref-output-double/pythia6_4.ref \
     functional_tests/ref-output-double/tauola_1.ref \
     functional_tests/ref-output-double/tauola_2.ref \
     functional_tests/ref-output-double/mlm_matching_isr.ref \
     functional_tests/ref-output-double/ewa_1.ref \
     functional_tests/ref-output-double/ewa_2.ref \
     functional_tests/ref-output-double/ewa_3.ref \
     functional_tests/ref-output-double/ilc.ref \
     functional_tests/ref-output-double/beam_events_2.ref \
     functional_tests/ref-output-double/beam_events_3.ref
 
 REF_OUTPUT_FILES_PREC = \
     functional_tests/ref-output-prec/qedtest_3.ref \
     functional_tests/ref-output-prec/qedtest_4.ref \
     functional_tests/ref-output-prec/qcdtest_1.ref \
     functional_tests/ref-output-prec/qcdtest_2.ref \
     functional_tests/ref-output-prec/qcdtest_3.ref \
     functional_tests/ref-output-prec/smtest_2.ref \
     functional_tests/ref-output-prec/smtest_8.ref \
     functional_tests/ref-output-prec/colors_2.ref \
     functional_tests/ref-output-prec/beam_setup_5.ref \
     functional_tests/ref-output-prec/nlo_3.ref \
     functional_tests/ref-output-prec/nlo_4.ref \
     functional_tests/ref-output-prec/fks_res_1.ref \
     functional_tests/ref-output-prec/fks_res_3.ref \
     functional_tests/ref-output-prec/openloops_3.ref \
     functional_tests/ref-output-prec/defaultcuts.ref \
     functional_tests/ref-output-prec/parton_shower_2.ref \
     functional_tests/ref-output-prec/helicity.ref \
     functional_tests/ref-output-prec/lhef_7.ref \
     functional_tests/ref-output-prec/multi_comp_1.ref \
     functional_tests/ref-output-prec/multi_comp_2.ref \
     functional_tests/ref-output-prec/multi_comp_3.ref \
     functional_tests/ref-output-prec/pdf_builtin.ref \
     functional_tests/ref-output-prec/lhapdf5.ref \
     functional_tests/ref-output-prec/lhapdf6.ref \
     functional_tests/ref-output-prec/ep_1.ref \
     functional_tests/ref-output-prec/ep_2.ref \
     functional_tests/ref-output-prec/ilc.ref \
     functional_tests/ref-output-prec/circe1_9.ref \
     functional_tests/ref-output-prec/circe1_photons_1.ref \
     functional_tests/ref-output-prec/circe1_photons_2.ref \
     functional_tests/ref-output-prec/circe1_photons_3.ref \
     functional_tests/ref-output-prec/circe1_photons_4.ref \
     functional_tests/ref-output-prec/circe1_photons_5.ref \
     functional_tests/ref-output-prec/ewa_1.ref
 
 REF_OUTPUT_FILES_EXT = \
     functional_tests/ref-output-ext/observables_2.ref \
     functional_tests/ref-output-ext/resonances_1.ref \
     functional_tests/ref-output-ext/resonances_2.ref \
     functional_tests/ref-output-ext/resonances_3.ref \
     functional_tests/ref-output-ext/resonances_4.ref \
     functional_tests/ref-output-ext/resonances_10.ref \
     functional_tests/ref-output-ext/resonances_11.ref \
     functional_tests/ref-output-ext/circe1_4.ref \
     functional_tests/ref-output-ext/circe1_5.ref \
     functional_tests/ref-output-ext/circe1_7.ref \
     functional_tests/ref-output-ext/circe1_8.ref \
     functional_tests/ref-output-ext/isr_2.ref \
     functional_tests/ref-output-ext/isr_3.ref \
     functional_tests/ref-output-ext/isr_4.ref \
     functional_tests/ref-output-ext/isr_5.ref \
     functional_tests/ref-output-ext/nlo_5.ref \
     functional_tests/ref-output-ext/powheg_1.ref \
     functional_tests/ref-output-ext/pythia6_3.ref \
     functional_tests/ref-output-ext/pythia6_4.ref \
     functional_tests/ref-output-ext/tauola_1.ref \
     functional_tests/ref-output-ext/tauola_2.ref \
     functional_tests/ref-output-ext/ewa_2.ref \
     functional_tests/ref-output-ext/ewa_3.ref \
     functional_tests/ref-output-ext/beam_events_2.ref \
     functional_tests/ref-output-ext/beam_events_3.ref \
     functional_tests/ref-output-ext/mlm_matching_isr.ref \
     functional_tests/ref-output-ext/hepmc_8.ref \
     functional_tests/ref-output-ext/lcio_2.ref \
     functional_tests/ref-output-ext/lcio_7.ref
 
 REF_OUTPUT_FILES_QUAD = \
     functional_tests/ref-output-quad/observables_2.ref \
     functional_tests/ref-output-quad/resonances_1.ref \
     functional_tests/ref-output-quad/resonances_2.ref \
     functional_tests/ref-output-quad/resonances_3.ref \
     functional_tests/ref-output-quad/resonances_4.ref \
     functional_tests/ref-output-quad/resonances_10.ref \
     functional_tests/ref-output-quad/resonances_11.ref \
     functional_tests/ref-output-quad/circe1_4.ref \
     functional_tests/ref-output-quad/circe1_5.ref \
     functional_tests/ref-output-quad/circe1_7.ref \
     functional_tests/ref-output-quad/circe1_8.ref \
     functional_tests/ref-output-quad/isr_2.ref \
     functional_tests/ref-output-quad/isr_3.ref \
     functional_tests/ref-output-quad/isr_4.ref \
     functional_tests/ref-output-quad/isr_5.ref \
     functional_tests/ref-output-quad/nlo_5.ref \
     functional_tests/ref-output-quad/powheg_1.ref \
     functional_tests/ref-output-quad/pythia6_3.ref \
     functional_tests/ref-output-quad/pythia6_4.ref \
     functional_tests/ref-output-quad/tauola_1.ref \
     functional_tests/ref-output-quad/tauola_2.ref \
     functional_tests/ref-output-quad/ewa_2.ref \
     functional_tests/ref-output-quad/ewa_3.ref \
     functional_tests/ref-output-quad/beam_events_2.ref \
     functional_tests/ref-output-quad/beam_events_3.ref \
     functional_tests/ref-output-quad/mlm_matching_isr.ref \
     functional_tests/ref-output-quad/hepmc_8.ref \
     functional_tests/ref-output-quad/lcio_2.ref \
     functional_tests/ref-output-quad/lcio_7.ref
 
 TESTSUITES_M4 = \
     $(MISC_TESTS_M4) \
     $(EXT_MSSM_M4) \
     $(EXT_NMSSM_M4)
 
 TESTSUITES_SIN = \
     $(MISC_TESTS_SIN) \
     $(EXT_ILC_SIN) \
     $(EXT_MSSM_SIN) \
     $(EXT_NMSSM_SIN) \
     $(EXT_SHOWER_SIN) \
     $(EXT_NLO_SIN) \
     $(EXT_NLO_ADD_SIN)
 
 
 MISC_TESTS_M4 =
 
 MISC_TESTS_SIN = \
     functional_tests/empty.sin \
     functional_tests/fatal.sin \
+    functional_tests/cmdline_1_a.sin \
+    functional_tests/cmdline_1_b.sin \
+    functional_tests/cmdline_1.sin \
     functional_tests/pack_1.sin \
     functional_tests/defaultcuts.sin \
     functional_tests/cuts.sin \
     functional_tests/model_change_1.sin \
     functional_tests/model_change_2.sin \
     functional_tests/model_change_3.sin \
     functional_tests/model_scheme_1.sin \
     functional_tests/model_test.sin \
     functional_tests/structure_1.sin \
     functional_tests/structure_2.sin \
     functional_tests/structure_3.sin \
     functional_tests/structure_4.sin \
     functional_tests/structure_5.sin \
     functional_tests/structure_6.sin \
     functional_tests/structure_7.sin \
     functional_tests/structure_8.sin \
     functional_tests/vars.sin \
     functional_tests/extpar.sin \
     functional_tests/testproc_1.sin \
     functional_tests/testproc_2.sin \
     functional_tests/testproc_3.sin \
     functional_tests/testproc_4.sin \
     functional_tests/testproc_5.sin \
     functional_tests/testproc_6.sin \
     functional_tests/testproc_7.sin \
     functional_tests/testproc_8.sin \
     functional_tests/testproc_9.sin \
     functional_tests/testproc_10.sin \
     functional_tests/testproc_11.sin \
     functional_tests/testproc_12.sin \
     functional_tests/template_me_1.sin \
     functional_tests/template_me_2.sin \
     functional_tests/libraries_1.sin \
     functional_tests/libraries_2.sin \
     functional_tests/libraries_3.sin \
     functional_tests/libraries_4.sin \
     functional_tests/job_id_1.sin \
     functional_tests/job_id_2.sin \
     functional_tests/job_id_3.sin \
     functional_tests/job_id_4.sin \
     functional_tests/rebuild_1.sin \
     functional_tests/rebuild_2.sin \
     functional_tests/rebuild_3.sin \
     functional_tests/rebuild_4.sin \
     functional_tests/rebuild_5.sin \
     functional_tests/qedtest_1.sin \
     functional_tests/qedtest_2.sin \
     functional_tests/qedtest_3.sin \
     functional_tests/qedtest_4.sin \
     functional_tests/qedtest_5.sin \
     functional_tests/qedtest_6.sin \
     functional_tests/qedtest_7.sin \
     functional_tests/qedtest_8.sin \
     functional_tests/qedtest_9.sin \
     functional_tests/qedtest_10.sin \
     functional_tests/rambo_vamp_1.sin \
     functional_tests/rambo_vamp_2.sin \
     functional_tests/beam_setup_1.sin \
     functional_tests/beam_setup_2.sin \
     functional_tests/beam_setup_3.sin \
     functional_tests/beam_setup_4.sin \
     functional_tests/beam_setup_5.sin \
     functional_tests/qcdtest_1.sin \
     functional_tests/qcdtest_2.sin \
     functional_tests/qcdtest_3.sin \
     functional_tests/qcdtest_4.sin \
     functional_tests/qcdtest_5.sin \
     functional_tests/qcdtest_6.sin \
     functional_tests/observables_1.sin \
     functional_tests/observables_2.sin \
     functional_tests/event_weights_1.sin \
     functional_tests/event_weights_2.sin \
     functional_tests/event_eff_1.sin \
     functional_tests/event_eff_2.sin \
     functional_tests/event_dump_1.sin \
     functional_tests/event_dump_2.sin \
     functional_tests/reweight_1.sin \
     functional_tests/reweight_2.sin \
     functional_tests/reweight_3.sin \
     functional_tests/reweight_4.sin \
     functional_tests/reweight_5.sin \
     functional_tests/reweight_6.sin \
     functional_tests/reweight_7.sin \
     functional_tests/reweight_8.sin \
     functional_tests/analyze_1.sin \
     functional_tests/analyze_2.sin \
     functional_tests/analyze_3.sin \
     functional_tests/analyze_4.sin \
     functional_tests/analyze_5.sin \
     functional_tests/analyze_6.sin \
     functional_tests/bjet_cluster.sin \
     functional_tests/colors.sin \
     functional_tests/colors_2.sin \
     functional_tests/colors_hgg.sin \
     functional_tests/alphas.sin \
     functional_tests/jets_xsec.sin \
     functional_tests/lhef_1.sin \
     functional_tests/lhef_2.sin \
     functional_tests/lhef_3.sin \
     functional_tests/lhef_4.sin \
     functional_tests/lhef_5.sin \
     functional_tests/lhef_6.sin \
     functional_tests/lhef_7.sin \
     functional_tests/lhef_8.sin \
     functional_tests/lhef_9.sin \
     functional_tests/lhef_10.sin \
     functional_tests/lhef_11.sin \
     functional_tests/select_1.sin \
     functional_tests/select_2.sin \
     functional_tests/shower_err_1.sin \
     functional_tests/parton_shower_1.sin \
     functional_tests/parton_shower_2.sin \
     functional_tests/pythia6_1.sin \
     functional_tests/pythia6_2.sin \
     functional_tests/pythia6_3.sin \
     functional_tests/pythia6_4.sin \
     functional_tests/pythia8_1.sin \
     functional_tests/pythia8_2.sin \
     functional_tests/hadronize_1.sin \
     functional_tests/tauola_1.sin \
     functional_tests/tauola_2.sin \
     functional_tests/mlm_matching_fsr.sin \
     functional_tests/mlm_matching_isr.sin \
     functional_tests/mlm_pythia6_isr.sin \
     functional_tests/hepmc_1.sin \
     functional_tests/hepmc_2.sin \
     functional_tests/hepmc_3.sin \
     functional_tests/hepmc_4.sin \
     functional_tests/hepmc_5.sin \
     functional_tests/hepmc_6.sin \
     functional_tests/hepmc_7.sin \
     functional_tests/hepmc_8.sin \
     functional_tests/hepmc_9.sin \
     functional_tests/hepmc_10.sin \
     functional_tests/stdhep_1.sin \
     functional_tests/stdhep_2.sin \
     functional_tests/stdhep_3.sin \
     functional_tests/stdhep_4.sin \
     functional_tests/stdhep_5.sin \
     functional_tests/stdhep_6.sin \
     functional_tests/lcio_1.sin \
     functional_tests/lcio_2.sin \
     functional_tests/lcio_3.sin \
     functional_tests/lcio_4.sin \
     functional_tests/lcio_5.sin \
     functional_tests/lcio_6.sin \
     functional_tests/lcio_7.sin \
     functional_tests/lcio_8.sin \
     functional_tests/lcio_9.sin \
     functional_tests/lcio_10.sin \
     functional_tests/fatal_beam_decay.sin \
     functional_tests/smtest_1.sin \
     functional_tests/smtest_2.sin \
     functional_tests/smtest_3.sin \
     functional_tests/smtest_4.sin \
     functional_tests/smtest_5.sin \
     functional_tests/smtest_6.sin \
     functional_tests/smtest_7.sin \
     functional_tests/smtest_8.sin \
     functional_tests/smtest_9.sin \
     functional_tests/smtest_10.sin \
     functional_tests/smtest_11.sin \
     functional_tests/smtest_12.sin \
     functional_tests/smtest_13.sin \
     functional_tests/smtest_14.sin \
     functional_tests/smtest_15.sin \
     functional_tests/smtest_16.sin \
     functional_tests/photon_isolation_1.sin \
     functional_tests/photon_isolation_2.sin \
     functional_tests/resonances_1.sin \
     functional_tests/resonances_2.sin \
     functional_tests/resonances_3.sin \
     functional_tests/resonances_4.sin \
     functional_tests/resonances_5.sin \
     functional_tests/resonances_6.sin \
     functional_tests/resonances_7.sin \
     functional_tests/resonances_8.sin \
     functional_tests/resonances_9.sin \
     functional_tests/resonances_10.sin \
     functional_tests/resonances_11.sin \
     functional_tests/resonances_12.sin \
     functional_tests/sm_cms_1.sin \
     functional_tests/ufo_1.sin \
     functional_tests/ufo_2.sin \
     functional_tests/ufo_3.sin \
     functional_tests/ufo_4.sin \
     functional_tests/nlo_1.sin \
     functional_tests/nlo_2.sin \
     functional_tests/nlo_3.sin \
     functional_tests/nlo_4.sin \
     functional_tests/nlo_5.sin \
     functional_tests/nlo_6.sin \
     functional_tests/nlo_decay_1.sin \
     functional_tests/real_partition_1.sin \
     functional_tests/fks_res_1.sin \
     functional_tests/fks_res_2.sin \
     functional_tests/fks_res_3.sin \
     functional_tests/openloops_1.sin \
     functional_tests/openloops_2.sin \
     functional_tests/openloops_3.sin \
     functional_tests/openloops_4.sin \
     functional_tests/openloops_5.sin \
     functional_tests/openloops_6.sin \
     functional_tests/openloops_7.sin \
     functional_tests/openloops_8.sin \
     functional_tests/openloops_9.sin \
     functional_tests/openloops_10.sin \
     functional_tests/openloops_11.sin \
     functional_tests/openloops_12.sin \
     functional_tests/openloops_13.sin \
     functional_tests/recola_1.sin \
     functional_tests/recola_2.sin \
     functional_tests/recola_3.sin \
     functional_tests/recola_4.sin \
     functional_tests/recola_5.sin \
     functional_tests/recola_6.sin \
     functional_tests/recola_7.sin \
     functional_tests/recola_8.sin \
     functional_tests/powheg_1.sin \
     functional_tests/mssmtest_1.sin \
     functional_tests/mssmtest_2.sin \
     functional_tests/mssmtest_3.sin \
     functional_tests/spincor_1.sin \
     functional_tests/show_1.sin \
     functional_tests/show_2.sin \
     functional_tests/show_3.sin \
     functional_tests/show_4.sin \
     functional_tests/show_5.sin \
     functional_tests/method_ovm_1.sin \
     functional_tests/multi_comp_1.sin \
     functional_tests/multi_comp_2.sin \
     functional_tests/multi_comp_3.sin \
     functional_tests/multi_comp_4.sin \
     functional_tests/flvsum_1.sin \
     functional_tests/br_redef_1.sin \
     functional_tests/decay_err_1.sin \
     functional_tests/decay_err_2.sin \
     functional_tests/decay_err_3.sin \
     functional_tests/polarized_1.sin \
     functional_tests/pdf_builtin.sin \
     functional_tests/lhapdf5.sin \
     functional_tests/lhapdf6.sin \
     functional_tests/ep_1.sin \
     functional_tests/ep_2.sin \
     functional_tests/ep_3.sin \
     functional_tests/circe1_1.sin \
     functional_tests/circe1_2.sin \
     functional_tests/circe1_3.sin \
     functional_tests/circe1_4.sin \
     functional_tests/circe1_5.sin \
     functional_tests/circe1_6.sin \
     functional_tests/circe1_7.sin \
     functional_tests/circe1_8.sin \
     functional_tests/circe1_9.sin \
     functional_tests/circe1_10.sin \
     functional_tests/circe1_photons_1.sin \
     functional_tests/circe1_photons_2.sin \
     functional_tests/circe1_photons_3.sin \
     functional_tests/circe1_photons_4.sin \
     functional_tests/circe1_photons_5.sin \
     functional_tests/circe1_errors_1.sin \
     functional_tests/circe2_1.sin \
     functional_tests/circe2_2.sin \
     functional_tests/circe2_3.sin \
     functional_tests/isr_1.sin \
     functional_tests/isr_2.sin \
     functional_tests/isr_3.sin \
     functional_tests/isr_4.sin \
     functional_tests/isr_5.sin \
     functional_tests/epa_1.sin \
     functional_tests/epa_2.sin \
     functional_tests/isr_epa_1.sin \
     functional_tests/ewa_1.sin \
     functional_tests/ewa_2.sin \
     functional_tests/ewa_3.sin \
     functional_tests/ewa_4.sin \
     functional_tests/ilc.sin \
     functional_tests/gaussian_1.sin \
     functional_tests/gaussian_2.sin \
     functional_tests/beam_events_1.sin \
     functional_tests/beam_events_2.sin \
     functional_tests/beam_events_3.sin \
     functional_tests/beam_events_4.sin \
     functional_tests/energy_scan_1.sin \
     functional_tests/susyhit.sin \
     functional_tests/restrictions.sin \
     functional_tests/helicity.sin \
     functional_tests/process_log.sin \
     functional_tests/static_1.sin \
     functional_tests/static_1.exe.sin \
     functional_tests/static_2.sin \
     functional_tests/static_2.exe.sin \
     functional_tests/user_cuts.sin \
     functional_tests/user_prc_threshold_1.sin \
     functional_tests/cascades2_phs_1.sin \
     functional_tests/user_prc_threshold_2.sin \
     functional_tests/vamp2_1.sin \
     functional_tests/vamp2_2.sin
 
 EXT_MSSM_M4 = \
     ext_tests_mssm/mssm_ext-ee.m4 \
     ext_tests_mssm/mssm_ext-ee2.m4 \
     ext_tests_mssm/mssm_ext-en.m4 \
     ext_tests_mssm/mssm_ext-tn.m4 \
     ext_tests_mssm/mssm_ext-uu.m4 \
     ext_tests_mssm/mssm_ext-uu2.m4 \
     ext_tests_mssm/mssm_ext-uuckm.m4 \
     ext_tests_mssm/mssm_ext-dd.m4 \
     ext_tests_mssm/mssm_ext-dd2.m4 \
     ext_tests_mssm/mssm_ext-ddckm.m4 \
     ext_tests_mssm/mssm_ext-bb.m4 \
     ext_tests_mssm/mssm_ext-bt.m4 \
     ext_tests_mssm/mssm_ext-tt.m4 \
     ext_tests_mssm/mssm_ext-ug.m4 \
     ext_tests_mssm/mssm_ext-dg.m4 \
     ext_tests_mssm/mssm_ext-aa.m4 \
     ext_tests_mssm/mssm_ext-wa.m4 \
     ext_tests_mssm/mssm_ext-za.m4 \
     ext_tests_mssm/mssm_ext-ww.m4 \
     ext_tests_mssm/mssm_ext-wz.m4 \
     ext_tests_mssm/mssm_ext-zz.m4 \
     ext_tests_mssm/mssm_ext-gg.m4 \
     ext_tests_mssm/mssm_ext-ga.m4 \
     ext_tests_mssm/mssm_ext-gw.m4 \
     ext_tests_mssm/mssm_ext-gz.m4
 
 EXT_NMSSM_M4 = \
     ext_tests_nmssm/nmssm_ext-aa.m4  \
     ext_tests_nmssm/nmssm_ext-bb1.m4 \
     ext_tests_nmssm/nmssm_ext-bb2.m4 \
     ext_tests_nmssm/nmssm_ext-bt.m4  \
     ext_tests_nmssm/nmssm_ext-dd1.m4 \
     ext_tests_nmssm/nmssm_ext-dd2.m4 \
     ext_tests_nmssm/nmssm_ext-ee1.m4 \
     ext_tests_nmssm/nmssm_ext-ee2.m4 \
     ext_tests_nmssm/nmssm_ext-en.m4  \
     ext_tests_nmssm/nmssm_ext-ga.m4  \
     ext_tests_nmssm/nmssm_ext-gg.m4  \
     ext_tests_nmssm/nmssm_ext-gw.m4  \
     ext_tests_nmssm/nmssm_ext-gz.m4  \
     ext_tests_nmssm/nmssm_ext-qg.m4  \
     ext_tests_nmssm/nmssm_ext-tn.m4  \
     ext_tests_nmssm/nmssm_ext-tt1.m4 \
     ext_tests_nmssm/nmssm_ext-tt2.m4 \
     ext_tests_nmssm/nmssm_ext-uu1.m4 \
     ext_tests_nmssm/nmssm_ext-uu2.m4 \
     ext_tests_nmssm/nmssm_ext-wa.m4  \
     ext_tests_nmssm/nmssm_ext-ww1.m4 \
     ext_tests_nmssm/nmssm_ext-ww2.m4 \
     ext_tests_nmssm/nmssm_ext-wz.m4  \
     ext_tests_nmssm/nmssm_ext-za.m4  \
     ext_tests_nmssm/nmssm_ext-zz1.m4 \
     ext_tests_nmssm/nmssm_ext-zz2.m4
 
 EXT_MSSM_SIN = $(EXT_MSSM_M4:.m4=.sin)
 EXT_NMSSM_SIN = $(EXT_NMSSM_M4:.m4=.sin)
 
 EXT_ILC_SIN = \
     ext_tests_ilc/ilc_ext.sin
 
 EXT_SHOWER_SIN = \
     ext_tests_shower/shower_1_norad.sin \
     ext_tests_shower/shower_2_aall.sin \
     ext_tests_shower/shower_3_bb.sin \
     ext_tests_shower/shower_3_jj.sin \
     ext_tests_shower/shower_3_qqqq.sin \
     ext_tests_shower/shower_3_tt.sin \
     ext_tests_shower/shower_3_z_nu.sin \
     ext_tests_shower/shower_3_z_tau.sin \
     ext_tests_shower/shower_4_ee.sin \
     ext_tests_shower/shower_5.sin \
     ext_tests_shower/shower_6.sin
 
 EXT_NLO_SIN = \
     ext_tests_nlo/nlo_settings.sin \
     ext_tests_nlo/nlo_eejj.sin \
     ext_tests_nlo/nlo_eejjj.sin \
     ext_tests_nlo/nlo_ee4j.sin \
     ext_tests_nlo/nlo_ee5j.sin \
     ext_tests_nlo/nlo_eebb.sin \
     ext_tests_nlo/nlo_eebbj.sin \
     ext_tests_nlo/nlo_eebbjj.sin \
     ext_tests_nlo/nlo_ee4b.sin \
     ext_tests_nlo/nlo_eett.sin \
     ext_tests_nlo/nlo_eettj.sin \
     ext_tests_nlo/nlo_eettjj.sin \
     ext_tests_nlo/nlo_eettjjj.sin \
     ext_tests_nlo/nlo_eettbb.sin \
     ext_tests_nlo/nlo_eetta.sin \
     ext_tests_nlo/nlo_eettaa.sin \
     ext_tests_nlo/nlo_eettaj.sin \
     ext_tests_nlo/nlo_eettajj.sin \
     ext_tests_nlo/nlo_eettaz.sin \
     ext_tests_nlo/nlo_eettah.sin \
     ext_tests_nlo/nlo_eettz.sin \
     ext_tests_nlo/nlo_eettzj.sin \
     ext_tests_nlo/nlo_eettzjj.sin \
     ext_tests_nlo/nlo_eettzz.sin \
     ext_tests_nlo/nlo_eettwjj.sin \
     ext_tests_nlo/nlo_eettww.sin \
     ext_tests_nlo/nlo_eetth.sin \
     ext_tests_nlo/nlo_eetthj.sin \
     ext_tests_nlo/nlo_eetthjj.sin \
     ext_tests_nlo/nlo_eetthh.sin \
     ext_tests_nlo/nlo_eetthz.sin \
     ext_tests_nlo/nlo_ee4t.sin \
     ext_tests_nlo/nlo_ee4tj.sin \
     ext_tests_nlo/nlo_ppzz.sin \
     ext_tests_nlo/nlo_ppzw.sin \
     ext_tests_nlo/nlo_pptttt.sin
 
 EXT_NLO_ADD_SIN = \
     ext_tests_nlo_add/nlo_decay_tbw.sin \
     ext_tests_nlo_add/nlo_tt.sin \
     ext_tests_nlo_add/nlo_tt_powheg.sin \
     ext_tests_nlo_add/nlo_tt_powheg_sudakov.sin \
     ext_tests_nlo_add/nlo_uu.sin \
     ext_tests_nlo_add/nlo_uu_powheg.sin \
     ext_tests_nlo_add/nlo_qq_powheg.sin \
     ext_tests_nlo_add/nlo_threshold.sin \
     ext_tests_nlo_add/nlo_threshold_factorized.sin \
     ext_tests_nlo_add/nlo_methods_gosam.sin \
     ext_tests_nlo_add/nlo_jets.sin \
     ext_tests_nlo_add/nlo_fks_delta_o_eejj.sin \
     ext_tests_nlo_add/nlo_fks_delta_i_ppee.sin
 
 all-local: $(TESTSUITES_SIN)
 
 if M4_AVAILABLE
 SUFFIXES = .m4 .sin
 .m4.sin:
 	case "$@" in \
 	*/*) \
 		mkdir -p `sed 's,/.[^/]*$$,,g' <<< "$@"` ;; \
 	esac
 	$(M4) $(srcdir)/$(TESTSUITE_MACROS) $< > $@
 endif M4_AVAILABLE
Index: trunk/share/tests/functional_tests/ref-output/cmdline_1.ref
===================================================================
--- trunk/share/tests/functional_tests/ref-output/cmdline_1.ref	(revision 0)
+++ trunk/share/tests/functional_tests/ref-output/cmdline_1.ref	(revision 8347)
@@ -0,0 +1,6 @@
+[user variable] i = 4
+[user variable] a = 12
+[user variable] b = 5
+[user variable] q = 3
+| WHIZARD run finished.
+|=============================================================================|
Index: trunk/share/tests/functional_tests/cmdline_1_a.sin
===================================================================
--- trunk/share/tests/functional_tests/cmdline_1_a.sin	(revision 0)
+++ trunk/share/tests/functional_tests/cmdline_1_a.sin	(revision 8347)
@@ -0,0 +1,2 @@
+int a = 2
+a = 3
Index: trunk/share/tests/functional_tests/cmdline_1.sin
===================================================================
--- trunk/share/tests/functional_tests/cmdline_1.sin	(revision 0)
+++ trunk/share/tests/functional_tests/cmdline_1.sin	(revision 8347)
@@ -0,0 +1,7 @@
+?logging = true
+
+show (i)
+show (a)
+show (b)
+show (q)
+
Index: trunk/share/tests/functional_tests/cmdline_1_b.sin
===================================================================
--- trunk/share/tests/functional_tests/cmdline_1_b.sin	(revision 0)
+++ trunk/share/tests/functional_tests/cmdline_1_b.sin	(revision 8347)
@@ -0,0 +1,2 @@
+int b = 5
+
Index: trunk/share/doc/manual.tex
===================================================================
--- trunk/share/doc/manual.tex	(revision 8346)
+++ trunk/share/doc/manual.tex	(revision 8347)
@@ -1,17527 +1,17548 @@
 \documentclass[12pt]{book}
 % \usepackage{feynmp}
 \usepackage{microtype}
 \usepackage{graphics,graphicx}
 \usepackage{color}
 \usepackage{amsmath,amssymb}
 \usepackage[colorlinks,bookmarks,bookmarksnumbered=true]{hyperref}
 \usepackage{thophys}
 \usepackage{fancyvrb}
 \usepackage{makeidx}
 \usepackage{units}
 \usepackage{ifpdf}
 %HEVEA\pdftrue
 \makeindex
 \usepackage{url}
 \usepackage[latin1]{inputenc}
 %HEVEA\@def@charset{UTF-8}
 %BEGIN LATEX
 \usepackage{supertabular,fancyvrb}
 \usepackage{hevea}
 %END LATEX
 \renewcommand{\topfraction}{0.9}
 \renewcommand{\bottomfraction}{0.8}
 \renewcommand{\textfraction}{0.1}
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 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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 \begin{document}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %BEGIN LATEX
 \preprintno{}
 %%%\preprintno{arXiv:0708.4233 (also based on LC-TOOL-2001-039 (revised))}
 %END LATEX
 \title{%
 %HEVEA WHIZARD 2.8 \\
 %BEGIN LATEX
  \ttt{\huge WHIZARD 2.8} \\[\baselineskip]
 %END LATEX
  A generic \\ Monte-Carlo integration and event generation package \\
  for multi-particle processes\\[\baselineskip]
  MANUAL
  \footnote{%
  This work is supported by Helmholtz-Alliance ``Physics at the
  Terascale''.
  In former stages this work has also been supported by
  the Helmholtz-Gemeinschaft VH--NG--005 \\
  E-mail: \ttt{whizard@desy.de}
  }
  \\[\baselineskip]
 }
 % \def\authormail{\ttt{kilian@physik.uni-siegen.de},
 %   \ttt{ohl@physik.uni-wuerzburg.de},
 %   \ttt{juergen.reuter@desy.de}, \ttt{cnspeckn@googlemail.com}}
 \author{%
   Wolfgang Kilian,%
   Thorsten Ohl,%
   J\"urgen Reuter,%
   with contributions from
   Fabian Bach, %
   Simon Bra\ss,
   Bijan Chokouf\'{e} Nejad, %
   Christian Fleper, %
   Vincent Rothe, %
   Sebastian Schmidt, %
   Marco Sekulla, %
   Christian Speckner, %
   So Young Shim, %
   Florian Staub, %
   Christian Weiss}
 
 %BEGIN LATEX
 \address{%
  Universit\"at Siegen, Emmy-Noether-Campus, Walter-Flex-Str. 3,
  D--57068 Siegen, Germany \\
  Universit\"at W\"urzburg, Emil-Hilb-Weg 22,
  D--97074 W\"urzburg, Germany \\
  Deutsches Elektronen-Synchrotron DESY, Notkestr. 85,
  D--22603 Hamburg, Germany \\
  %% \authormail
  \vspace{1cm}
  \begin{center}
  \includegraphics[width=4cm]{Whizard-Logo}
  \end{center}
  \mbox{} \\
  \vspace{2cm}
  \mbox{} when using \whizard\ please cite: \\
  W. Kilian, T. Ohl, J. Reuter, \\ {\em WHIZARD: Simulating Multi-Particle
  Processes at LHC and ILC}, \\
  Eur.Phys.J.{\bf C71} (2011) 1742, arXiv:
  0708.4233 [hep-ph]; \\
  M. Moretti, T. Ohl, J. Reuter, \\ {\em O'Mega: An Optimizing Matrix
  Element Generator}, \\
  arXiv: hep-ph/0102195
 }
 %END LATEX
 %BEGIN LATEX
 \abstract{%
 \whizard\ is a program system designed for the efficient calculation
 of multi-particle scattering cross sections and simulated event
 samples.  The generated events can be written to file in various formats
 (including HepMC, LHEF, STDHEP, LCIO, and ASCII) or analyzed directly on the
 parton or hadron level using a built-in \LaTeX-compatible graphics
 package.
 \\[\baselineskip]
 Complete tree-level matrix elements are generated automatically for arbitrary
 partonic multi-particle processes by calling the built-in matrix-element
 generator \oMega.  Beyond hard matrix elements, \whizard\ can generate
 (cascade) decays with complete spin correlations.
 Various models beyond the SM are implemented, in particular,
 the MSSM is supported with an interface to the SUSY Les Houches Accord
 input format.  Matrix elements obtained by alternative methods (e.g.,
 including loop corrections) may be interfaced as well.
 \\[\baselineskip]
 The program uses an adaptive multi-channel method for phase space
 integration, which allows to calculate numerically stable signal and
 background cross sections and generate unweighted event samples with
 reasonable efficiency for processes with up to eight and more
 final-state particles.  Polarization is treated exactly for both the
 initial and final states.  Quark or lepton flavors can be
 summed over automatically where needed.
 \\[\baselineskip]
 For hadron collider physics, we ship the package with the most recent
 PDF sets from the MSTW/MMHT and CTEQ/CT10/CJ12/CJ15/CT14
 collaborations. Furthermore, an interface to the \lhapdf\ library is
 provided.
 \\[\baselineskip]
 For Linear Collider physics,
 beamstrahlung (\circeone, \circetwo), Compton and ISR spectra are
 included for electrons and photons, including the most recent ILC and
 CLIC collider designs. Alternatively, beam-crossing events can be read
 directly from file.
 \\[\baselineskip]
 For parton showering and matching/merging with hard matrix elements ,
 fragmenting and hadronizing the final state, a first version of two
 different parton shower algorithms are included in the \whizard\
 package. This also includes infrastructure for the MLM matching and
 merging algorithm. For hadronization and hadronic decays, \pythia\
 and \herwig\ interfaces are provided which follow the Les Houches
 Accord. In addition, the last and final version of (\fortran) \pythia\
 is included in the package.
 \\[\baselineskip]
 The \whizard\ distribution is available at
 %%% \begin{center}
 %%%   \ttt{http://whizard.event-generator.org}
 %%% \end{center}
 %%% or at
 \begin{center}
   \url{https://whizard.hepforge.org}
 \end{center}
 where also the \ttt{svn} repository is located.
 }
 %END LATEX
 %
 \maketitle
 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%% Text
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %\begin{fmffile}
 \tableofcontents
 
 \newpage
 \chapter{Introduction}
 
 \section{Disclaimer}
 
 \emph{This is a preliminary version of the WHIZARD manual.  Many parts
   are still missing or incomplete, and some parts will be rewritten and
   improved soon.  To find updated versions of the manual,
   visit the \whizard\ website}
 \begin{center}
   \hepforgepage
 \end{center}
 \emph{or consult the current version in the \ttt{svn} repository
   on \hepforgepage\ directly. Note, that the most recent version of
   the manual might contain information about features of the
   current \ttt{svn} version, which are not contained in the last
   official release version!}
 
 \emph{For information that is not (yet) written in the manual, please
 consult the examples in the \whizard\ distribution.  You will find these in
 the subdirectory \ttt{share/examples} of the main directory where
 \whizard\ is installed. More information about the examples can be
 found on the \whizard\ Wiki page}
 \begin{center}
   \whizardwiki .
 \end{center}
 
 %%%%%
 
 \clearpage
 \section{Overview}
 
 \whizard\ is a multi-purpose event generator that covers all parts of
 event generation (unweighted and weighted), either through intrinsic
 components or interfaces to external packages. Realistic collider
 environments are covered through sophisticated descriptions for beam
 structures at hadron colliders, lepton colliders, lepton-hadron
 colliders, both circular and linear machines. Other options include
 scattering processes e.g. for dark matter annihilation or particle
 decays. \whizard\ contains its in-house generator for (tree-level)
 high-multiplicity matrix elements, \oMega\, that supports the whole
 Standard Model (SM) of particle physics and basically all possibile
 extensions of it. QCD parton shower describe high-multiplicity
 partonic jet events that can be matched with matrix elements. At the
 moment, only hadron collider parton distribution functions (PDFs) and
 hadronization are handled by packages not written by the main
 authors.
 
 This manual is organized mainly along the lines of the way how to run
 \whizard: this is done through a command language, \sindarin\ (Scripting
 INtegration, Data Analysis, Results display and INterfaces.) Though
 this seems a complication at first glance, the user is rewarded with a
 large possibility, flexibility and versatility on how to steer
 \whizard.
 
 After some general remarks in the follow-up sections, in
 Chap.~\ref{chap:installation} we describe how to get the program, the
 package structure, the prerequisites, possible external extensions of
 the program and the basics of the installation (both as superuser and
 locally). Also, a first technical overview how to work with \whizard\
 on single computer, batch clusters and farms are given. Furthermore,
 some rare uncommon possible build problems are discussed, and a tour
 through options for debugging, testing and validation is being made.
 
 A first dive into the running of the program is made in
 Chap.~\ref{chap:start}. This is following by an extensive, but rather
 technical introduction into the steering language \sindarin\ in
 Chap.~\ref{chap:sindarinintro}. Here, the basic elements of the
 language like commands, statements, control structures, expressions
 and variables as well as the form of warnings and error messages are
 explained in detail.
 
 Chap.~\ref{chap:sindarin} contains the application of the \sindarin\
 command language to the main tasks in running \whizard\ in a physics
 framework: the defintion of particles, subevents, cuts, and event
 selections. The specification of a particular physics models is
 \begin{figure}[t]
   \centering
   \includegraphics[width=0.9\textwidth]{whizstruct}
   \caption{General structure of the \whizard\ package.}
 \end{figure}
 discussed, while the next sections are devoted to the setup and
 compilation of code for particular processes, the specification of
 beams, beam structure and polarization. The next step is the
 integration, controlling the integration, phase space, generator cuts,
 scales and weights, proceeding further to event generation and
 decays. At the end of this chapter, \whizard's internal data analysis
 methods and graphical visualization options are documented.
 
 The following chapters are dedicated to the physics implemented in
 \whizard: methods for hard matrix interactions in
 Chap.~\ref{chap:hardint}. Then, in Chap.~\ref{chap:physics},
 implemented methods for adaptive multi-channel integration,
 particularly the integrator \vamp\ are explained, together with the
 algorithms for the generation of the phase-space in \whizard. Finally,
 an overview is given over the physics models implemented in \whizard\
 and its matrix element generator \oMega, together with possibilities
 for their extension. After that, the next chapter discusses parton
 showering, matching and hadronization as well as options for event
 normalizations and supported event formats. Also weighted event
 generation is explained along the lines with options for negative
 weights. Then, in Chap.~\ref{chap:user}, options for user to plug-in
 self-written code into the \whizard\ framework are detailed, e.g. for
 observables, selections and cut functions, or for spectra and
 structure functions. Also, static executables are discussed.
 
 Chap.~\ref{chap:visualization} is a stand-alone documentation of
 GAMELAN, the interal graphics support for the visualization of data
 and analysis. The next chapter, Chap.~\ref{chap:userint} details user
 interfaces: how to use more options of the \whizard\ command on the
 command line, how to use \whizard\ interactively, and how to include
 \whizard\ as a library into the user's own program.
 
 Then, an extensive list of examples in Chap.~\ref{chap:examples}
 documenting physics examples from the LEP, SLC, HERA, Tevatron, and
 LHC colliders to future linear and circular colliders. This chapter is
 a particular good reference for the beginning, as the whole chain from
 choosing a model, setting up processes, the beam structure, the
 integration, and finally simulation and (graphical) analysis are
 explained in detail.
 
 More technical details about efficiency, tuning and advance usage of
 \whizard\ are collected in Chap.~\ref{chap:tuning}. Then,
 Chap.~\ref{chap:extmodels} shows how to set up your own new physics
 model with the help of external programs like \sarah\ or
 \FeynRules\ program or the Universal Feynrules Output, UFO, and
 include it into the \whizard\ event generator.
 
 In the appendices, we e.g. give an exhaustive reference list of
 \sindarin\ commands and built-in variables.
 
 Please report any inconsistencies, bugs, problems or simply pose open
 questions to our contact \url{whizard@desy.de}.
 
 
 %%%%%
 
 \section{Historical remarks}
 
 This section gives a historical overview over the development of
 \whizard\ and can be easily skipped in a (first) reading of the
 manual. \whizard\ has been developed in a first place as a tool for
 the physics at the then planned linear electron-positron collider
 TESLA around 1999. The intention was to have a tool at hand to
 describe electroweak physics of multiple weak bosons and the Higgs
 boson as precise as possible with full matrix elements. Hence, the
 acronym: \ttt{WHiZard}, which stood for $\mathbf{W}$, {\bf H}iggs,
 $\mathbf{Z}$, {\bf a}nd {\bf r}espective {\bf d}ecays.
 
 Several components of the \whizard\ package that are also available as
 independent sub-packages have been published already before the first
 versions of the \whizard\ generator itself: the multi-channel adaptive
 Monte-Carlo integration package \vamp\ has been released mid
 1998~\cite{VAMP}. The dedicated packages for the simulation of linear
 lepton collider beamstrahlung and the option for a photon collider on
 Compton backscattering (\ttt{CIRCE1/2}) date back even to mid
 1996~\cite{CIRCE}. Also parts of the code for \whizard's internal
 graphical analysis (the \gamelan\ module) came into existence already
 around 1998.
 
 After first inofficial versions, the official version 1 of \whizard\
 was release in the year 2000. The development, improvement and
 incorporation of new features continued for roughly a decade. Major
 milestones in the development were the full support of all kinds of
 beyond the Standard Model (BSM) models including spin 3/2 and spin 2
 particles and the inclusion of the MSSM, the NMSSM, Little Higgs
 models and models for anomalous couplings as well as extra-dimensional
 models from version 1.90 on. In the beginning, several methods for
 matrix elements have been used, until the in-house matrix element
 generator \oMega\ became available from version 1.20 on. It was
 included as a part of the \whizard\ package from version 1.90 on. The
 support for full color amplitudes came with version 1.50, but in a
 full-fledged version from 2.0 on. Version 1.40 brought the necessary
 setups for all kinds of collider environments, i.e. asymmetric beams,
 decay processes, and intrinsic $p_T$ in structure functions.
 
 Version 2.0 was released in April 2010 as an almost complete rewriting
 of the original code. It brought the construction of an internal
 density-matrix formalism which allowed the use of factorized
 production and (cascade) decay processes including complete color and
 spin correlations. Another big new feature was the command-line
 language \sindarin\ for steering all parts of the program. Also, many
 performance improvement have taken place in the new release series,
 like OpenMP parallelization, speed gain in matrix element generation
 etc. Version 2.2 came out in May 2014 as a major refactoring of the
 program internals but keeping (almost everywhere) the same user
 interface. New features are inclusive processes, reweighting, and more
 interfaces for QCD environments (BLHA/HOPPET).
 
 The following tables shows some of the major steps (physics
 implementation and/or technical improvements) in the development
 of \whizard:
 
 \begin{center}
 \begin{tabular}{|l|l|l|}\hline
   0.99 & 08/1999 & Beta version \\\hline
   1.00 & 12/2000 & First public version \\\hline
   1.10 & 03/2001 & Libraries; \pythiasix\ interface \\
   1.11 & 04/2001 & PDF support; anomalous couplings \\ \hline
   1.20 & 02/2002 & \oMega\ matrix elements; \ttt{CIRCE} support\\
   1.22 & 03/2002 & QED ISR; beam remnants, phase space improvements \\
   1.25 & 05/2003 & MSSM; weighted events; user-code plug-in \\
   1.28 & 04/2004 & Improved phase space; SLHA interface; signal catching
   \\\hline
   1.30 & 09/2004 & Major technical overhaul \\\hline
   1.40 & 12/2004 & Asymmetric beams; decays; $p_T$ in structure
   functions \\\hline
   1.50 & 02/2006 & QCD support in \oMega\ (color flows); LHA format \\
   1.51 & 06/2006 & $Hgg$, $H\gamma\gamma$; Spin 3/2 + 2; BSM models
   \\\hline
   1.90 & 11/2007 & \oMega\ included; LHAPDF support; $Z'$; $WW$ scattering \\
   1.92 & 03/2008 & LHE format; UED; parton shower beta version \\
   1.93 & 04/2009 & NMSSM; SLHA2 accord; improved color/flavor sums \\
   1.95 & 02/2010 & MLM matching; development stop in version 1
   \\
   1.97 & 05/2011 & Manual for version 1 completed. \\\hline\hline
 %%% \end{tabular}
 %%% \end{center}
 %%% \begin{center}
 %%% \begin{tabular}{|l|l|l|}\hline
   2.0.0 & 04/2010 & Major refactoring: automake setup; dynamic
   libraries \\
   & & improved speed; cascades; OpenMP; \sindarin\ steering language \\
   2.0.3 & 07/2010 & QCD ISR+FSR shower; polarized beams \\
   2.0.5 & 05/2011 & Builtin PDFs; static builds; relocation scripts \\
   2.0.6 & 12/2011 & Anomalous top couplings; unit tests \\\hline
   2.1.0 & 06/2012 & Analytic ISR+FSR parton shower; anomalous Higgs
   couplings \\\hline
   2.2.0 & 05/2014 & Major technical refactoring: abstract
   object-orientation; THDM; \\
   & & reweighting; LHE v2/3; BLHA; HOPPET interface; inclusive
   processes \\
   2.2.1 & 05/2014 & CJ12 PDFs; FastJet interface \\
   2.2.2 & 07/2014 & LHAPDF6 support; correlated LC beams; GuineaPig
   interface \\
   2.2.3 & 11/2014 & O'Mega virtual machine; lepton collider top
   pair threshold; Higgs singlet extension \\
   2.2.4 & 02/2015 & LCIO support; progress on NLO; many technical
   bug fixes \\
   2.2.7 & 08/2015 & progress on POWHEG; fixed-order NLO events;
   revalidation of ILC event chain \\
   2.2.8 & 11/2015 & support for quadruple precision; StdHEP included;
   SM dim 6 operators supported
   \\\hline
   2.3.0 & 07/2016 & NLO: resonance mappings for FKS subtraction; more
   advanced cascade syntax; \\
   & & GUI ($\alpha$ version); UFO support
   ($\alpha$ version); ILC v1.9x-v2.x final validation \\
   2.3.1 & 08/2016 & Complex mass scheme
   \\\hline
   2.4.0 & 11/2016 & Refactoring of NLO setup \\
   2.4.1 & 03/2017 & $\alpha$ version of new VEGAS implementation
   \\\hline
   2.5.0 & 05/2017 & Full UFO support (SM-like models)
   \\\hline
   2.6.0 & 09/2017 & MPI parallel integration and event generation;
   resonance histories \\
   & & for showers; RECOLA support \\
   2.6.1 & 11/2017 & EPA/ISR transverse distributions, handling of
   shower resonances; \\
   & & more efficient (alternative) phase space generation \\
   2.6.2 & 12/2017 & $Hee$ coupling, improved resonance matching \\
   2.6.3 & 02/2018 & Partial NLO refactoring for quantum numbers,
   unified RECOLA 1/2 interface. \\
   2.6.4 & 08/2018 & Gridpack functionality; Bug fixes: color flows,
   HSExt model, MPI setup
   \\\hline
   2.7.0 & 01/2019 & PYTHIA8 interface, process setup refactoring,
   RAMBO PS option; \\
   & & \quad gfortran 5.0+ necessary
   \\\hline
   2.8.0 & 08/2019 & (Almost) complete UFO support, general Lorentz
   structures, n-point vertices \\
   2.8.1 & 09/2019 & HepMC3, NLO QCD pp (almost)
   complete, b/c jet selection, photon isolation \\
   2.8.2 & 10/2019 & Support for OCaml $\geq$ 4.06.0, UFO Spin-2 support,
   LCIO alternative weights
   \\\hline
 \end{tabular}
 \end{center}
 
 \vspace{.5cm}
 
 For a detailed overview over the historical development of the code
 confer the \ttt{ChangeLog} file and the commit messages in our
 revision control system repository.
 
 %%%%%
 
 \section{About examples in this manual}
 
 Although \whizard\ has been designed as a Monte Carlo event generator
 for LHC physics, several elementary steps and aspects of its usage
 throughout the manual will be demonstrated with the famous textbook
 example of $e^+e^- \to \mu^+ \mu^-$. This is the same process, the
 textbook by Peskin/Schroeder \cite{PeskinSchroeder} uses as a prime
 example to teach the basics of quantum field theory. We use this
 example not because it is very special for \whizard\ or at the time
 being a relevant physics case, but simply because it is the easiest
 fundamental field theoretic process without the complications of
 structured beams (which can nevertheless be switched on like for ISR
 and beamstrahlung!), the need for jet definitions/algorithms and
 flavor sums; furthermore, it easily accomplishes a demonstration of
 polarized beams. After the basics of \whizard\ usage have been
 explained, we move on to actual physics cases from LHC (or Tevatron).
 
 
 \newpage
 \chapter{Installation}
 \label{chap:installation}
 
 \section{Package Structure}
 
 \whizard\ is a software package that consists of a main executable
 program (which is called \ttt{whizard}), libraries, auxiliary
 executable programs, and machine-independent data files.  The whole
 package can be installed by the system administrator, by default, on a
 central location in the file system (\ttt{/usr/local} with its proper
 subdirectories).  Alternatively, it is possible to install it in a
 user's home directory, without administrator privileges, or at any
 other location.
 
 A \whizard\ run requires a workspace, i.e., a writable directory where
 it can put generated code and data.  There are no constraints on the
 location of this directory, but we recommend to use a separate
 directory for each \whizard\ project, or even for each \whizard\ run.
 
 Since \whizard\ generates the matrix elements for scattering and decay
 processes in form of \fortran\ code that is automatically compiled and
 dynamically linked into the running program, it requires a working
 \fortran\ compiler not just for the installation, but also at runtime.
 
 The previous major version \whizard1 did put more constraints on the
 setup.  In a nutshell, not just the matrix element code was compiled
 at runtime, but other parts of the program as well, so the whole
 package was interleaved and had to be installed in user space.  The
 workflow was controlled by \ttt{make} and PERL scripts.  These
 constraints are gone in the present version in favor of a clean
 separation of installation and runtime workspace.
 
 
 \section{\label{sec:prerequisites}Prerequisites}
 
 \subsection{No Binary Distribution}
 
 \whizard\ is currently not distributed as a binary package, nor is it
 available as a debian or RPM package.  This might change in the
 future.  However, compiling from source is very simple (see below).
 Since the package needs a compiler also at runtime, it would not work
 without some development tools installed on the machine, anyway.
 
 Note, however, that we support an install script, that downloads all
 necessary prerequisites, and does the configuration and compilation
 described below automatically. This is called the ``instant WHIZARD''
 and is accessible through the WHIZARD webpage from version 2.1.1 on:
 \url{https://whizard.hepforge.org/versions/install/install-whizard-2.X.X.sh}.
 Download this shell script, make it executable by
 \begin{interaction}
   chmod +x install-whizard-2.X.X.sh
 \end{interaction}
 and execute it. Note that this also involves compilation of the
 required \ttt{Fortran} compiler which takes 1-3 hours depending on
 your system.
 \ttt{Darwin} operating systems (a.k.a. as \ttt{Mac OS X}) have a very
 similar general system for all sorts of software, called
 \ttt{MacPorts} (\url{http://www.macports.org}). This offers to install
 \whizard\ as one of its software ports, and is very similar to
 ``instant WHIZARD'' described above.
 
 
 \subsection{Tarball Distribution}
 
 This is the recommended way of obtaining \whizard.  You may download
 the current stable distribution from the \whizard\ webpage,
 hosted at the HepForge webpage
 \begin{quote}
   \hepforgepage
 \end{quote}
 The distribution is a single file, say \ttt{whizard-\thisversion.tgz} for
 version \thisversion.
 
 You need the additional prerequisites:
 \begin{itemize}
 \item
   GNU \ttt{tar} (or \ttt{gunzip} and \ttt{tar}) for unpacking the
   tarball.
 \item
   The \ttt{make} utility.  Other standard Unix utilities (\ttt{sed},
   \ttt{grep}, etc.) are usually installed by default.
 \item
   A modern \fortran\ compiler (see Sec.~\ref{sec:compilers} for
   details).
 \item
   The \ocaml\ system.  \ocaml\ is a functional and object-oriented
   language.  Version 4.02.3 or newer is required to compile all
   components of \whizard. The package is freely available either as a
   debian/RPM package on your system (it might be necessary to install
   it from the usual repositories), or you can obtain it directly from
   \begin{quote}
     \url{http://caml.inria.fr}
   \end{quote}
   and install it yourself.  If desired, the package can be installed
   in user space without administrator privileges\footnote{
     Unfortunately, the version of the \ocaml\
     compiler from 3.12.0 broke backwards compatibility. Therefore,
     versions of \oMega/\whizard\ up to 2.0.2 only compile with older
     versions (3.11.x works). This has been fixed in versions
     2.0.3 and later. See also
     Sec.~\ref{sec:buildproblems}. \whizard\ versions up to 2.7.1 were
     still backwards compatible with \ocaml\ 3.12.0}.
 \end{itemize}
 The following optional external packages are not required, but used
 for certain purposes.  Make sure to check whether you will need any of
 them, before you install \whizard.
 \begin{itemize}
 \item
   \LaTeX\ and \metapost\ for data visualization.  Both are part of the
   \TeX\ program family.  These programs are not absolutely necessary,
   but \whizard\ will lack the tools for visualization without them.
 \item
   The \lhapdf\ structure-function library.  See
   Sec.~\ref{sec:lhapdf_install}.
 \item
   The \hoppet\ structure-function matching tool. See
   Sec.~\ref{sec:hoppet}.
 \item
   The \hepmc\ event-format package.  See Sec.~\ref{sec:hepmc}.
 \item
   The \fastjet\ jet-algorithm package.  See Sec.~\ref{sec:fastjet}.
 \item
   The \lcio\ event-format package.  See Sec.~\ref{sec:lcio}.
 \end{itemize}
 Until version v2.2.7 of \whizard, the event-format package \stdhep\ used
 to be available as an external package. As their distribution is frozen
 with the final version v5.06.01, and it used to be notoriously difficult to
 compile and link \stdhep\ into \whizard, it was decided to include \stdhep\
 into \whizard. This is the case from version v2.2.8 of \whizard\ on. Linking
 against an external version of \stdhep\ is precluded from there
 on. Nevertheless, we list some explanations in Sec.~\ref{sec:stdhep},
 particularly on the need to install the \ttt{libtirpc} headers for the
 legacy support of this event format. Once these prerequisites are met,
 you may unpack the package in a directory of your choice
 \begin{quote}\small\tt
   some-directory> tar xzf whizard-\thisversion.tgz
 \end{quote}
 and proceed.\footnote{Without GNU \ttt{tar}, this would read
   \ttt{\small gunzip -c whizard-\thisversion.tgz | tar xz -}}
 
 For using external physics models that are directly supported by
 \whizard\ and \oMega, the user can use tools like \sarah\ or
 \FeynRules. There installation and linking to \whizard\ will be
 explained in Chap.~\ref{chap:extmodels}. Besides this, also new models
 can be conveniently included via \UFO\ files, which will be explained
 as well in that chapter.
 
 The directory will then contain a subdirectory \ttt{whizard-\thisversion}
 where the complete source tree is located.  To update later to a new
 version, repeat these steps.  Each new version will unpack in a
 separate directory with the appropriate name.
 
 
 \subsection{SVN Repository Version}
 
 If you want to install the latest development version, you have to
 check it out from the \whizard\ SVN repository.
 
 In addition to the prerequisites listed in the previous section, you
 need:
 \begin{itemize}
 \item
   The \ttt{subversion} package (\ttt{svn}), the tool for dealing with
   SVN repositories.
 \item
   The \ttt{autoconf} package, part of the \ttt{autotools} development
   system. \ttt{automake} is needed with version \ttt{1.12.2} or newer.
 \item
   The \ttt{noweb} package, a light-weight tool for literate programming.  This
   package is nowadays often part of Linux distributions\footnote{In
     Ubuntu from version 10.04 on, and in Debian since
     squeeze. For \ttt{Mac OS X}, \ttt{noweb} is available via the
     \ttt{MacPorts} system.}.  You can obtain the source code
   from\footnote{Please, do not use any of the binary builds from this
     webpage. Probably all of them are quite old and broken.}
   \begin{quote}
     \url{http://www.cs.tufts.edu/~nr/noweb/}
   \end{quote}
 \end{itemize}
 To start, go to a directory of your choice and execute
 \begin{interaction}
   your-src-directory> svn checkout
   svn+ssh://vcs@phab.hepforge.org/source/whizardsvn/trunk \;\; .
 \end{interaction}
 Note that for the time being after the HepForge system modernization
 early September 2018, a HepForge account with a local ssl key is
 necessary to checkout the subversion repository. This is enforced by
 the phabricator framework of HepForge, and will hopefully be relaxed
 in the future. The SVN source tree will appear in the current
 directory.  To update later, you just have to execute
 \begin{interaction}
   your-src-directory> svn update
 \end{interaction}
 within that directory.
 
 After checking out the sources, you first have to create
 \ttt{configure.ac} by executing the shell script
 \ttt{build\_master.sh}. In order to build the \ttt{configure}
 script, the \ttt{autotools} package \ttt{autoreconf} has to be run. On
 some \ttt{Unix} systems the \ttt{RPC} headers needed for the legacy
 support of the \stdhep\ event format are provided by the \ttt{TIRPC}
 library (cf. Sec.~\ref{sec:stdhep}). To easily check for them,
 \ttt{configure.ac} processed by \ttt{autoreconf} makes use of the
 \ttt{pkg-config} tool which needs to be installed for the developer
 version. So now, run\footnote{At least, version
   2.65 of the \ttt{autoconf} package is required.}
 \begin{interaction}
   your-src-directory> autoreconf
 \end{interaction}
 This will generate a \ttt{configure} script.
 
 
 \subsection{\label{sec:compilers}Fortran Compilers}
 
 \whizard\ is written in modern \fortran.  To be precise, it uses a
 subset of the \fortranOThree\ standard.  At the time of this writing,
 this subset is supported by, at least, the following compilers:
 \begin{itemize}
 \item
   \ttt{gfortran} (GNU, Open Source).  You will need version 5.1.0
   or higher\footnote{Note that \whizard\ versions 2.0.0 until 2.3.1 compiled
   with \ttt{gfortran} 4.7.4, but the object-oriented
   refactoring of the \whizard\ code from 2.4.0 on until version 2.6.5
   made a switch to \ttt{gfortran} 4.8.4 or higher necessary. In the
   same way, since version 2.7.0, \ttt{gfortran} 5.1.0 or newer is
   needed}. We recommend to use at least version 5.4 or higher, as
   especially the the early version of the \texttt{gfortran} experience
   some bugs. \ttt{gfortran} 6.5.0 has a severe regression and cannot
   be used.
 \item
   \ttt{nagfor} (NAG).  You will need version 6.2 or higher.
 \item
   \ttt{ifort} (Intel). You will need version 17.0.4 or
   higher. Version 19.0.0 unfortunately has a severe regression and
   cannot be used.
 \end{itemize}
 
 %%%%%
 
 \subsection{LHAPDF}
 \label{sec:lhapdf_install}
 
 For computing scattering processes at hadron colliders such as the
 LHC, \whizard\ has a small set of standard structure-function
 parameterizations built in, cf.\ Sec.~\ref{sec:built-in-pdf}.  For
 many applications, this will be sufficient, and you can skip this
 section.
 
 However, if you need structure-function parameterizations that are not
 in the default set (e.g. PDF error sets), you can use the \lhapdf\
 structure-function library, which is an external package.  It has to
 be linked during \whizard\ installation.  For use with \whizard,
 version 5.3.0 or higher of the library is required\footnote{ Note that
   PDF sets which contain photons as partons are only supported with
   \whizard\ for \lhapdf\ version 5.7.1 or higher}. The \lhapdf\
 package has undergone a major rewriting from \fortran\ version 5
 to \ttt{C++} version 6. While still maintaining the interface for
 the \lhapdf\ version 5 series, from version 2.2.2 of \whizard\ on, the
 new release series of \lhapdf, version 6.0 and higher, is also
 supported.
 
 If \lhapdf\ is not yet installed on your system, you can download it from
 \begin{quote}
   \url{https://lhapdf.hepforge.org}
 \end{quote}
 for the most recent LHAPDF version 6 and newer, or
 \begin{quote}
   \url{https://lhapdf.hepforge.org/lhapdf5}
 \end{quote}
 for version 5 and older, and install it.  The website contains
 comprehensive documentation on the configuring and installation
 procedure.  Make sure that you have downloaded and installed not just
 the package, but also the data sets. Note that \lhapdf\ version 5
 needs both a \fortran\ and a \ttt{C++} compiler.
 
 During \whizard\ configuration, \whizard\ looks for the script
 \ttt{lhapdf} (which is present in \lhapdf\ series 6) first, and then
 for \ttt{lhapdf-config} (which is present since \lhapdf\ version
 4.1.0): if those are in an executable path (or only
 the latter for \lhapdf\ version 5), the environment variables for
 \lhapdf\ are automatically recognized by \whizard, as well as the
 version number. This should look like this in the \ttt{configure}
 output (for \lhapdf\ version 6 or newer),
 
 \begin{footnotesize}
 \begin{verbatim}
    configure: --------------------------------------------------------------
    configure: --- LHAPDF ---
    configure:
    checking for lhapdf... /usr/local/bin/lhapdf
    checking for lhapdf-config... /usr/local/bin/lhapdf-config
    checking the LHAPDF version... 6.2.1
    checking the major version... 6
    checking the LHAPDF pdfsets path... /usr/local/share/LHAPDF
    checking the standard PDF sets...  all standard PDF sets installed
    checking if LHAPDF is functional... yes
    checking LHAPDF... yes
    configure: --------------------------------------------------------------
 \end{verbatim}
 \end{footnotesize}
 while for \lhapdf\ version 5 and older it looks like this:
 
 \begin{footnotesize}
 \begin{verbatim}
    configure: --------------------------------------------------------------
    configure: --- LHAPDF ---
    configure:
    checking for lhapdf... no
    checking for lhapdf-config... /usr/local/bin/lhapdf-config
    checking the LHAPDF version... 5.9.1
    checking the major version... 5
    checking the LHAPDF pdfsets path... /usr/local/share/lhapdf/PDFsets
    checking the standard PDF sets...  all standard PDF sets installed
    checking for getxminm in -lLHAPDF... yes
    checking for has_photon in -lLHAPDF... yes
    configure: --------------------------------------------------------------
 \end{verbatim}
 \end{footnotesize}
 
 If you want to use a different \lhapdf\ (e.g. because the one installed
 on your system by default is an older one), the preferred way to do so
 is to put the \ttt{lhapdf} (and/or \ttt{lhapdf-config}) scripts in an
 executable path that is checked before the system paths,
 e.g. \ttt{<home>/bin}.
 
 For the old series, \lhapdf\ version 5, a possible error could arise
 if \lhapdf\ had been compiled with a different \fortran\ compiler than
 \whizard, and if the run-time library of that \fortran\ compiler had
 not been included in the \whizard\ configure process. The output then
 looks like this:
 
 \begin{footnotesize}
 \begin{verbatim}
    configure: --------------------------------------------------------------
    configure: --- LHAPDF ---
    configure:
    checking for lhapdf... no
    checking for lhapdf-config... /usr/local/bin/lhapdf-config
    checking the LHAPDF version... 5.9.1
    checking the major version... 5
    checking the LHAPDF pdfsets path... /usr/local/share/lhapdf/PDFsets
    checking for standard PDF sets... all standard PDF sets installed
    checking for getxminm in -lLHAPDF... no
    checking for has_photon in -lLHAPDF... no
    configure: --------------------------------------------------------------
 \end{verbatim}
 \end{footnotesize}
 
 So, the \whizard\ configure found the \lhapdf\ distribution, but could
 not link because it could not resolve the symbols inside the
 library. In case of failure, for more details confer the
 \ttt{config.log}.
 
 If \lhapdf\ is installed in a non-default directory where
 \whizard\ would not find it, set the environment variable
 \ttt{LHAPDF\_DIR} to the correct installation path when configuring
 \whizard.
 
 The check for the standard PDF sets are those sets that are used in
 the default \whizard\ self tests in the case \lhapdf\ is enabled and
 correctly linked. If some of them are missing, then this test will
 result in a failure. They are the \ttt{CT10} set for \lhapdf\ version
 6 (for version 5, \ttt{cteq61.LHpdf}, \ttt{cteq6ll.LHpdf},
 \ttt{cteq5l.LHgrid}, and \ttt{GSG961.LHgrid} are demanded). If you
 want to use \lhapdf\ inside \whizard\ please install them such that
 \whizard\ could perform all its sanity checks with them. The last
 check is for the \ttt{has\_photon} flag, which tests whether photon
 PDFs are available in the found \lhapdf\ installation.
 
 %%%%%
 
 \subsection{HOPPET}
 \label{sec:hoppet}
 
 \hoppet\ (not Hobbit) is a tool for the QCD DGLAP evolution of PDFs
 for hadron colliders. It provides possibilities for matching
 algorithms for 4- and 5-flavor schemes, that are important for
 precision simulations of $b$-parton initiated processes at hadron
 colliders. If you are not interested in those features, you can skip
 this section. Note that this feature is not enabled by default (unlike
 e.g. \lhapdf), but has to be explicitly during the configuration
 (see below):
 \begin{interaction}
   your-build-directory> your-src-directory/configure --enable-hoppet
 \end{interaction}
 If you \ttt{configure} messages like the following:
 \begin{footnotesize}
 \begin{verbatim}
 configure: --------------------------------------------------------------
 configure: --- HOPPET ---
 configure:
 checking for hoppet-config... /usr/local/bin/hoppet-config
 checking for hoppetAssign in -lhoppet_v1... yes
 checking the HOPPET version... 1.2.0
 configure: --------------------------------------------------------------
 \end{verbatim}
 \end{footnotesize}
 then you know that \hoppet\ has been found and was correctly
 linked. If that is not the case, you have to specify the location of
 the \hoppet\ library, e.g. by adding
 \begin{interaction}
   HOPPET=<hoppet\_directory>/lib
 \end{interaction}
 to the \ttt{configure} options above. For more details, please confer
 the \hoppet\ manual.
 
 %%%%%
 
 \subsection{HepMC}
 \label{sec:hepmc}
 
 With version 2.8.1, \whizard\ supports both the "classical" version 2
 as well as the newly designed version 3 (release 2019). The configure
 step can successfully recognize the two  different versions, the user
 do not have to specify which version is installed.
 
 \hepmc\ is a \ttt{C++} class library for handling collider scattering
 events.  In particular, it provides a portable format for event files.
 If you want to use this format, you should link \whizard\ with \hepmc,
 otherwise you can skip this section.
 
 If it is not already installed on your system, you may obtain
 \hepmc\ from one of these two webpages:
 \begin{quote}
   \url{http://hepmc.web.cern.ch/hepmc/}
 \end{quote}
 or
 \begin{quote}
   \url{http://hepmc.web.cern.ch/hepmc/}
 \end{quote}
 If the \hepmc\ library is linked with the installation, \whizard\ is
 able to read and write files in the \hepmc\ format.
 
 Detailed information on the installation and usage can be found on the
 \hepmc\ homepage. We give here only some brief details relevant for
 the usage with \whizard: For the compilation of HepMC one needs a
 \ttt{C++} compiler. Then the procedure is the same as for the
 \whizard\ package, namely configure HepMC:
 \begin{interaction}
   configure --with-momentum=GEV --with-length=MM --prefix=<install dir>
 \end{interaction}
 Note that the particle momentum and decay length flags are mandatory, and
 we highly recommend to set them to the values \ttt{GEV} and \ttt{MM},
 respectively. After configuration, do \ttt{make}, an optional
 \ttt{make check} (which might sometimes fail for non-standard values
 of momentum and length), and finally \ttt{make install}.
 
 The latest version of \hepmc\ (2.6.10) as well as the new relase
 series use \texttt{cmake} for their build process. For more
 information, confer the \hepmc\ webpage.
 
 A \whizard\ configuration for HepMC looks like this:
 \begin{footnotesize}
   \begin{verbatim}
    configure: --------------------------------------------------------------
    configure: --- HepMC ---
    configure:
    checking for HepMC-config... no
    checking HepMC3 or newer... no
    configure: HepMC3 not found, incompatible, or HepMC-config not found
    configure: looking for HepMC2 instead ...
    checking the HepMC version... 2.06.10
    checking for GenEvent class in -lHepMC... yes
    configure: --------------------------------------------------------------
   \end{verbatim}
 \end{footnotesize}
 
 If \hepmc\ is installed in a non-default directory where \whizard\
 would not find it, set the environment variable \ttt{HEPMC\_DIR} to
 the correct installation path when configuring \whizard.  Furthermore,
 the environment variable \ttt{CXXFLAGS} allows you to set specific
 \ttt{C/C++} preprocessor flags, e.g. non-standard include paths for
 header files.
 
 %%%%%
 
 \subsection{PYTHIA8}
 \label{sec:pythia8}
 
 \emph{NOTE: This is at the moment not yet supported, but merely a stub
 with the only purpose to be recognized by the build system.}
 
 \pythiaeight\ is a \ttt{C++} class library for handling hadronization,
 showering and underlying event. If you want to use this feature (once it is
 fully supported in \whizard), you should link \whizard\ with \pythiaeight,
 otherwise you can skip this section.
 
 If it is not already installed on your system, you may obtain
 \pythiaeight\ from
 \begin{quote}
   \url{http://home.thep.lu.se/~torbjorn/Pythia.html}
 \end{quote}
 If the \pythiaeight\ library is linked with the installation, \whizard\ will
 be able to use its hadronization and showering, once this is fully supported
 within \whizard.
 
 To link a \pythiaeight\ installation to \whizard, you should specify the flag
 \begin{quote}
 \ttt{--enable-pythia8}
 \end{quote}
 to \ttt{configure}.  If  \pythiaeight\ is installed in a non-default directory
 where \whizard\ would not find it, specify also
 \begin{quote}
 \ttt{--with-pythia8=\emph{<your-pythia8-installation-path>}}
 \end{quote}
 
 A successful \whizard\ configuration should produce a screen output
 similar to this:
 \begin{footnotesize}
 \begin{verbatim}
 configure: --------------------------------------------------------------
 configure: --- SHOWERS PYTHIA6 PYTHIA8 MPI ---
 configure:
 [....]
 checking for pythia8-config... /usr/local/bin/pythia8-config
 checking if PYTHIA8 is functional... yes
 checking PYTHIA8... yes
 configure: WARNING: PYTHIA8 configure is for testing purposes at the moment.
 configure: --------------------------------------------------------------
 \end{verbatim}
 \end{footnotesize}
 
 %%%%%
 
 \subsection{FastJet}
 \label{sec:fastjet}
 
 \fastjet\ is a \ttt{C++} class library for handling jet clustering.
 If you want to use this feature, you should link \whizard\ with \fastjet,
 otherwise you can skip this section.
 
 If it is not already installed on your system, you may obtain
 \fastjet\ from
 \begin{quote}
   \url{http://fastjet.fr}
 \end{quote}
 If the \fastjet\ library is linked with the installation, \whizard\ is
 able to call the jet algorithms provided by this program for the purposes of
 applying cuts and analysis.
 
 To link a \fastjet\ installation to \whizard, you should specify the flag
 \begin{quote}
 \ttt{--enable-fastjet}
 \end{quote}
 to \ttt{configure}.  If  \fastjet\ is installed in a non-default directory
 where \whizard\ would not find it, specify also
 \begin{quote}
 \ttt{--with-fastjet=\emph{<your-fastjet-installation-path>}}
 \end{quote}
 
 A successful \whizard\ configuration should produce a screen output
 similar to this:
 \begin{footnotesize}
 \begin{verbatim}
 configure: --------------------------------------------------------------
 configure: --- FASTJET ---
 configure:
 checking for fastjet-config... /usr/local/bin/fastjet-config
 checking if FastJet is functional... yes
 checking FastJet... yes
 checking the FastJet version... 3.3.0
 configure: --------------------------------------------------------------
 \end{verbatim}
 \end{footnotesize}
 
 %%%%%
 
 \subsection{STDHEP}
 \label{sec:stdhep}
 
 \stdhep\ is a  library for handling collider scattering
 events~\cite{stdhep}.  In particular, it provides a portable format
 for event files. Until version 2.2.7 of \whizard, \stdhep\ that was
 maintained by Fermilab, could be linked as an externally compiled
 library. As the \stdhep\ package is frozen in its final release
 v5.06.1 and no longer maintained, it has from version 2.2.8 been
 included \whizard. This eases many things, as it was notoriously
 difficult to compile and link \stdhep\ in a way compatible with
 \whizard. Not the full package has been included, but only the
 libraries for file I/O (\ttt{mcfio}, the library for the XDR
 conversion), while the various translation tools for \pythia, \herwig,
 etc.  have been abandoned. Note that \stdhep\ has largely been
 replaced in the hadron collider community by the \hepmc\ format, and
 in the lepton collider community by \lcio. \whizard\ might serve as a
 conversion tools for all these formats, but other tools also exist, of
 course. Note that the \ttt{mcfio} framework makes use of the \ttt{RPC}
 headers. These come -- provided by \ttt{SunOS/Oracle America, Inc.} -- 
 together with the system headers, but on some \ttt{Unix} systems
 (e.g. \ttt{ArchLinux}, \ttt{Fedora}) have been replaced by the
 \ttt{libtirpc} headers . The \ttt{configure} script searches for these
 headers so these have to be installed mandatorily. 
 
 If the \stdhep\ library is linked with the installation, \whizard\ is
 able to write files in the \stdhep\ format, the  corresponding
 configure output notifies you that \stdhep\ is always included:
 \begin{footnotesize}
 \begin{verbatim}
 configure: --------------------------------------------------------------
 configure: --- STDHEP ---
 configure:
 checking for pkg-config... /opt/local/bin/pkg-config
 checking pkg-config is at least version 0.9.0... yes
 checking for libtirpc... no
 configure: for StdHEP legacy code: using SunRPC headers and library
 configure: StdHEP v5.06.01 is included internally
 configure: --------------------------------------------------------------
 \end{verbatim}
 \end{footnotesize}
 
 %%%%%
 
 \subsection{LCIO}
 \label{sec:lcio}
 
 
 \lcio\ is a \ttt{C++} class library for handling collider scattering
 events.  In particular, it provides a portable format for event files.
 If you want to use this format, you should link \whizard\ with \lcio,
 otherwise you can skip this section.
 
 If it is not already installed on your system, you may obtain
 \lcio\ from:
 \begin{quote}
   \url{http://lcio.desy.de}
 \end{quote}
 If the \lcio\ library is linked with the installation, \whizard\ is
 able to read and write files in the \lcio\ format.
 
 Detailed information on the installation and usage can be found on the
 \lcio\ homepage. We give here only some brief details relevant for
 the usage with \whizard: For the compilation of \lcio\ one needs a
 \ttt{C++} compiler. \lcio\ is based on \ttt{cmake}. For the
 corresponding options please confer the \lcio\ manual.
 
 A \whizard\ configuration for \lcio\ looks like this:
 \begin{footnotesize}
   \begin{verbatim}
    configure: --------------------------------------------------------------
    configure: --- LCIO ---
    configure:
    checking the LCIO version... 2.12.1
    checking for LCEventImpl class in -llcio... yes
    configure: --------------------------------------------------------------
   \end{verbatim}
 \end{footnotesize}
 
 If \lcio\ is installed in a non-default directory where \whizard\
 would not find it, set the environment variable \ttt{LCIO} or
 \ttt{LCIO\_DIR} to the correct installation path when configuring
 \whizard.  The first one is the variable exported by the
 \ttt{setup.sh}  script while the second one is analogous to the
 environment variables of other external packages. \ttt{LCIO} takes
 precedence over \ttt{LCIO\_DIR}. Furthermore, the environment variable
 \ttt{CXXFLAGS} allows you to set specific \ttt{C/C++} preprocessor
 flags, e.g. non-standard include paths for header files.
 
 %%%%%
 
 \section{Installation}
 \label{sec:installation}
 
 Once you have unpacked the source (either the tarball or the SVN
 version), you are ready to compile it.  There are several options.
 
 
 \subsection{Central Installation}
 This is the default and recommended way, but it requires adminstrator
 privileges.  Make sure that all
 prerequisites are met (Sec.~\ref{sec:prerequisites}).
 \begin{enumerate}
 \item
   Create a fresh directory for the \whizard\ build.  It is recommended
   to keep this separate from the source directory.
 \item
   Go to that directory and execute
   \begin{interaction}
     your-build-directory> your-src-directory/configure
   \end{interaction}
   This will analyze your system and prepare the compilation of \whizard\
   in the build directory.  Make sure to set the proper options to
   \ttt{configure}, see Sec.~\ref{sec:configure-options} below.
 \item
   Call \ttt{make} to compile and link \whizard:
   \begin{interaction}
     your-build-directory> make
   \end{interaction}
 \item
   If you want to make sure that everything works, run
   \begin{interaction}
     your-build-directory> make check
   \end{interaction}
   This will take some more time.
 \item
   Become superuser and say
   \begin{interaction}
     your-build-directory> make install
   \end{interaction}
 \end{enumerate}
 \whizard\ should now installed in the default locations, and the
 executable should be available in the standard path.  Try to call
 \ttt{whizard --help} in order to check this.
 
 \subsection{Installation in User Space}
 You may lack administrator privileges on your system.  In that case,
 you can still install and run \whizard.  Make sure that all
 prerequisites are met (Sec.~\ref{sec:prerequisites}).
 \begin{enumerate}
 \item
   Create a fresh directory for the \whizard\ build.  It is recommended
   to keep this separate from the source directory.
 \item
   Reserve a directory in user space for the \whizard\ installation.
   It should be empty, or yet non-existent.
 \item
   Go to that directory and execute
   \begin{interaction}
     your-build-directory> your-src-directory/configure
                                --prefix=your-install-directory
   \end{interaction}
   This will analyze your system and prepare the compilation of \whizard\
   in the build directory.  Make sure to set the proper additional options to
   \ttt{configure}, see Sec.~\ref{sec:configure-options} below.
 \item
   Call \ttt{make} to compile and link \whizard:
   \begin{interaction}
     your-build-directory> make
   \end{interaction}
 \item
   If you want to make sure that everything works, run
   \begin{interaction}
     your-build-directory> make check
   \end{interaction}
   This will take some more time.
 \item
   Install:
   \begin{interaction}
     your-build-directory> make install
   \end{interaction}
 \end{enumerate}
 \whizard\ should now be installed in the installation directory of your
 choice.  If the installation is not in your standard search paths, you
 have to account for this by extending the paths appropriately, see
 Sec.~\ref{sec:workspace}.
 
 
 \subsection{Configure Options}
 \label{sec:configure-options}
 
 The configure script accepts environment variables and flags.  They
 can be given as arguments to the \ttt{configure} program in arbitrary
 order.  You may run \ttt{configure --help} for a listing; only the
 last part of this long listing is specific for the \whizard\ system.
 Here is an example:
 \begin{interaction}
   configure  FC=gfortran-5.4  FCFLAGS="-g -O3"  --enable-fc-openmp
 \end{interaction}
 
 The most important options are
 \begin{itemize}
 \item
   \ttt{FC} (variable): The \fortran\ compiler.  This is necessary if
   you need a compiler different from the standard compiler on the
   system, e.g., if the latter is too old.
 \item
   \ttt{FCFLAGS} (variable): The flags to be given to the Fortran
   compiler.  The main use is to control the level of optimization.
 \item
   \ttt{--prefix=\var{directory-name}}: Specify a non-default directory
   for installation.
 \item
   \ttt{--enable-fc-openmp}: Enable parallel executing via OpenMP on a
   multi-processor/multi-core machine.  This works only if OpenMP is
   supported by the compiler (e.g., \ttt{gfortran}).  When running
   \whizard, the number of processors that are actually requested can
   be controlled by the user.  Without this option, \whizard\ will run
   in serial mode on a single core.  See Sec.~\ref{sec:openmp} for
   further details.
 \item
   \ttt{--enable-fc-mpi}: Enable parallel executing via MPI on a single
   machine using several cores or several machines. This works only if a MPI
   library is installed (e.g. \ttt{OpenMPI}) and \ttt{FC=mpifort CC=mpicc CXX=mpic++} is
   set. Without this option, \whizard\ will run in serial mode on a single core.
   The flag can be combined with \ttt{--enable-fc-openmp}. See Sec.~\ref{sec:mpi}
   for further details.
 \item
   \ttt{LHADPF\_DIR} (variable): The location of the optional \lhapdf\
   package, if non-default.
 \item
   \ttt{LOOPTOOLS\_DIR} (variable): The location of the optional \ttt{LOOPTOOLS}
   package, if non-default.
 \item
   \ttt{OPENLOOPS\_DIR} (variable): The location of the optional \openloops\
   package, if non-default.
 \item
   \ttt{GOSAM\_DIR} (variable): The location of the optional \gosam\
   package, if non-default.
 \item
   \ttt{HOPPET\_DIR} (variable): The location of the optional \hoppet\
   package, if non-default.
 \item
   \ttt{HEPMC\_DIR} (variable): The location of the optional \hepmc\ package, if
   non-default.
 \item
   \ttt{LCIO}/\ttt{LCIO\_DIR} (variable): The location of the optional
   \lcio\ package, if non-default.
 \end{itemize}
 
 Other flags that might help to work around possible problems are the
 flags for the $C$ and $C++$ compilers as well as the \ttt{Fortran77}
 compiler, or the linker flags and additional libraries for the linking
 process.
 \begin{itemize}
 \item
   \ttt{CC} (variable): \ttt{C} compiler command
 \item
   \ttt{F77} (variable): \ttt{Fortran77} compiler command
 \item
   \ttt{CXX} (variable): \ttt{C++} compiler command
 \item
   \ttt{CPP} (variable): \ttt{C} preprocessor
 \item
   \ttt{CXXCPP} (variable): \ttt{C++} preprocessor
 \item
   \ttt{CFLAGS} (variable): \ttt{C} compiler flags
 \item
   \ttt{FFLAGS} (variable): \ttt{Fortran77} compiler flags
 \item
   \ttt{CXXFLAGS} (variable): \ttt{C++} compiler flags
 \item
   \ttt{LIBS} (variable): libraries to be passed to the linker as
   \ttt{-l{\em library}}
 \item
   \ttt{LDFLAGS} (variable): non-standard linker flags
 \end{itemize}
 
 For other options (like e.g. \ttt{--with-precision=...} etc.) please
 see the \ttt{configure --help} option.
 
 %%%%%
 
 \subsection{Details on the Configure Process}
 
 The configure process checks for the build and host system type; only
 if this is not detected automatically, the user would have to specify
 this by himself. After that system-dependent files are searched for,
 LaTeX and Acroread for documentation and plots, the \fortran\ compiler
 is checked, and finally the \ocaml\ compiler. The next step is the
 checks for external programs like \lhapdf\ and \ttt{HepMC}.
 Finally, all the Makefiles are being built.
 
 The compilation is done by invoking \ttt{make} and finally
 \ttt{make install}. You could also do a \ttt{make check} in
 order to test whether the compilation has produced sane files on your
 system. This is highly recommended.
 
 Be aware that there be problems for the installation if the install
 path or a user's home directory is part of an AFS file system. Several
 times problems were encountered connected with conflicts with
 permissions inside the OS permission environment variables and the AFS
 permission flags which triggered errors during the \ttt{make install}
 procedure. Also please avoid using \ttt{make -j} options of parallel
 execution of \ttt{Makefile} directives as AFS filesystems might not be
 fast enough to cope with this.
 
 For specific problems that might have been encountered in rare
 circumstances for some FORTRAN compilers confer the webpage
 \url{https://whizard.hepforge.org/compilers.html}.
 
 Note that the \pythia\  bundle for showering and hadronization (and
 some other external legacy code pieces) do still contain good old
 \ttt{Fortran77} code. These parts should better be
 compiled with the very same \ttt{Fortran2003} compiler as the
 \whizard\ core. There is, however, one subtlety:
 when the \ttt{configure} flag \ttt{FC} gets a full system path as
 argument, \ttt{libtool} is not able to recognize this as a valid (GNU)
 \ttt{Fortran77} compiler. It then searches automatically for binaries
 like \ttt{f77}, \ttt{g77} etc. or a standard system compiler. This
 might result in a compilation failure of the \ttt{Fortran77} code. A
 viable solution is to define an executable link and use this (not the
 full path!) as \ttt{FC} flag.
 
 It is possible to compile \whizard\ without the \ocaml\ parts of
 \oMega, namely by using the \ttt{--disable-omega} option of the
 configure. This will result in a built of \whizard\ with the \oMega\
 Fortran library, but without the binaries for the matrix element
 generation. All selftests (cf. \ref{sec:selftests}) requiring \oMega\
 matrix elements are thereby switched off. Note that you can install
 such a built (e.g. on a batch system without \ocaml\ installation), but
 the try to build a distribution (all \ttt{make distxxx} targets) will fail.
 
 
 %%%%%%%%%%%
 
 
 \subsection{\whizard\ self tests/checks}
 \label{sec:selftests}
 
 \whizard\ has a number of self-consistency checks and tests which assure
 that most of its features are running in the intended way. The
 standard procedure to invoke these self tests is to perform a
 \ttt{make check} from the \ttt{build} directory. If \ttt{src}
 and \ttt{build} directories are the same, all relevant files for
 these self-tests reside in the \ttt{tests} subdirectory of the main
 \whizard\ directory. In that case, one could in principle just call the
 scripts individually from the command line. Note, that if \ttt{src}
 and \ttt{build} directory are different as recommended, then the
 input files will have been installed in
 \ttt{prefix/share/whizard/test}, while the corresponding test shell
 scripts remain in the \ttt{srcdir/test} directory. As the main shell
 script \ttt{run\_whizard.sh} has been built in the \ttt{build}
 directory, one now has to copy the files over by and set the correct
 paths by hand, if one wishes to run the test scripts individually.
 \ttt{make check} still correctly performs all \whizard\
 self-consistency tests. The tests itself fall into two categories,
 unit self test that individually test the modular structure of
 \whizard, and tests that are run by \sindarin\ files. In future releases
 of \whizard, these two categories of tests will be better separated
 than in the 2.2.1 release.
 
 There are additional, quite extensiv numerical tests for validation
 and backwards compatibility checks for SM and MSSM processes. As a
 standard, these extended self tests are not invoked. However, they can
 be enabled by executing the corresponding specific \ttt{make check}
 operations in the subdirectories for these extensive tests.
 
 As the new \whizard\ testsuite does very thorough and scrupulous tests
 of the whole \whizard\ structure, it is always possible that some
 tests are failing due to some weird circumstances or because of
 numerical fluctuations. In such a case do not panic, contact the
 developers (\ttt{whizard@desy.de}) and provide them with the logfiles
 of the failing test as well as the setup of your configuration.
 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \clearpage
 
 \chapter{Working with \whizard}
 \label{chap:start}
 
 \whizard\ can run as a stand-alone program.  You (the user) can steer
 \whizard\ either interactively or by a script file.  We will first
 describe the latter method, since it will be the most common way to
 interact with the \whizard\ system.
 
 \section{Hello World}
 
 The legacy version series 1 of the program relied on a bunch of input
 files that the user had to provide in some obfuscated format.  This
 approach is sufficient for straightforward applications.  However, once
 you get experienced with a program, you start thinking about uses that
 the program's authors did not foresee.  In case of a Monte Carlo
 package, typical abuses are parameter scans, complex patterns of cuts
 and reweighting factors, or data analysis without recourse to external
 packages.  This requires more flexibility.
 
 Instead of transferring control over data input to some generic
 scripting language like PERL or PYTHON (or even C++), which come with
 their own peculiarities and learning curves, we decided to unify data
 input and scripting in a dedicated steering language that is
 particularly adapted to the needs of Monte-Carlo integration,
 simulation, and simple analysis of the results.  Thus we discovered
 what everybody knew anyway: that W(h)izards communicate in \sindarin,
 Scripting INtegration, Data Analysis, Results display and INterfaces.
 
 \sindarin\ is a DSL -- a domain-specific scripting language -- that is
 designed for the single purpose of steering and talking to \whizard.
 Now since \sindarin\ is a programming language, we honor the old
 tradition of starting with the famous Hello World program.  In
 \sindarin\ this reads simply
 \begin{quote}
 \begin{verbatim}
 printf "Hello World!"
 \end{verbatim}
 \end{quote}
 Open your favorite editor, type this text, and save it into a file
 named \verb|hello.sin|.
 
 \begin{figure}
   \centering
 \begin{scriptsize}
 \begin{Verbatim}[frame=single]
     | Writing log to 'whizard.log'
     |=============================================================================|
     |                                                                             |
     |    WW             WW  WW   WW  WW  WWWWWW      WW      WWWWW    WWWW        |
     |     WW    WW     WW   WW   WW  WW     WW      WWWW     WW  WW   WW  WW      |
     |      WW  WW WW  WW    WWWWWWW  WW    WW      WW  WW    WWWWW    WW   WW     |
     |       WWWW   WWWW     WW   WW  WW   WW      WWWWWWWW   WW  WW   WW  WW      |
     |        WW     WW      WW   WW  WW  WWWWWW  WW      WW  WW   WW  WWWW        |
     |                                                                             |
     |                                                                             |
     |                                        W                                    |
     |                                       sW                                    |
     |                                       WW                                    |
     |                                      sWW                                    |
     |                                      WWW                                    |
     |                                     wWWW                                    |
     |                                    wWWWW                                    |
     |                                    WW WW                                    |
     |                                    WW WW                                    |
     |                                   wWW WW                                    |
     |                                  wWW  WW                                    |
     |                                  WW   WW                                    |
     |                                  WW   WW                                    |
     |                                 WW    WW                                    |
     |                                 WW    WW                                    |
     |                                WW     WW                                    |
     |                                WW     WW                                    |
     |           wwwwww              WW      WW                                    |
     |              WWWWWww          WW      WW                                    |
     |                 WWWWWwwwww   WW       WW                                    |
     |                     wWWWwwwwwWW       WW                                    |
     |                 wWWWWWWWWWWwWWW       WW                                    |
     |                wWWWWW       wW        WWWWWWW                               |
     |                  WWWW       wW        WW  wWWWWWWWwww                       |
     |                   WWWW                      wWWWWWWWwwww                    |
     |                     WWWW                      WWWW     WWw                  |
     |                       WWWWww                   WWWW                         |
     |                           WWWwwww              WWWW                         |
     |                               wWWWWwww       wWWWWW                         |
     |                                     WwwwwwwwwWWW                            |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |  by:   Wolfgang Kilian, Thorsten Ohl, Juergen Reuter                        |
     |        with contributions from Christian Speckner                           |
     |        Contact: <whizard@desy.de>                                           |
     |                                                                             |
     |  if you use WHIZARD please cite:                                            |
     |        W. Kilian, T. Ohl, J. Reuter,  Eur.Phys.J.C71 (2011) 1742            |
     |                                          [arXiv: 0708.4233 [hep-ph]]        |
     |        M. Moretti, T. Ohl, J. Reuter, arXiv: hep-ph/0102195                 |
     |                                                                             |
     |=============================================================================|
     |                               WHIZARD 2.8.3
     |=============================================================================|
     | Reading model file '/usr/local/share/whizard/models/SM.mdl'
     | Preloaded model: SM
     | Process library 'default_lib': initialized
     | Preloaded library: default_lib
     | Reading commands from file 'hello.sin'
     Hello World!
     | WHIZARD run finished.
     |=============================================================================|
 \end{Verbatim}
 \end{scriptsize}
   \caption{Output of the \ttt{"Hello world!"} \sindarin\ script.\label{fig:helloworld}}
 \end{figure}
 
 Now we assume that you -- or your kind system administrator -- has
 installed \whizard\ in your executable path.  Then you should open a
 command shell and execute (we will come to the meaning of the
 \verb|-r| option later.)
 \begin{verbatim}
 /home/user$ whizard -r hello.sin
 \end{verbatim}
 and if everything works well, you get the output (the complete output
 including the \whizard\ banner is shown in Fig.~\ref{fig:helloworld})
 \begin{footnotesize}
 \begin{verbatim}
 | Writing log to 'whizard.log'
 \end{verbatim}
 \centerline{[... here a banner is displayed]}
 \begin{Verbatim}
 |=============================================================================|
 |                               WHIZARD 2.8.3
 |=============================================================================|
 | Reading model file '/usr/local/share/whizard/models/SM.mdl'
 | Preloaded model: SM
 ! Process library 'default_lib': initialized
 ! Preloaded library: default_lib
 | Reading commands from file 'hello.sin'
 Hello World!
 | WHIZARD run finished.
 |=============================================================================|
 \end{Verbatim}
 \end{footnotesize}
 If this has just worked for you, you can be confident that you have a working
 \whizard\ installation, and you have been able to successfully run the
 program.
 
 \section{A Simple Calculation}
 You may object that \whizard\ is not exactly designed for printing out
 plain text.  So let us demonstrate a more useful example.
 
 Looking at the Hello World output, we first observe that the program
 writes a log file named (by default) \verb|whizard.log|.  This file
 receives all screen output, except for the output of external programs
 that are called by \whizard.  You don't have to cache \whizard's screen
 output yourself.
 
 After the welcome banner, \whizard\ tells you that it reads a physics
 \emph{model}, and that it initializes and preloads a \emph{process library}.  The
 process library is initially empty.  It is ready for receiving
 definitions of elementary high-energy physics processes (scattering or
 decay) that you provide.  The processes are set in the context of a
 definite model of high-energy physics.  By default this is the
 Standard Model, dubbed \verb|SM|.
 
 Here is the \sindarin\ code for defining a SM physics process, computing
 its cross section, and generating a simulated event sample in Les Houches
 event format:
 \begin{quote}
 \begin{Verbatim}
 process ee = e1, E1 => e2, E2
 sqrts = 360 GeV
 n_events = 10
 sample_format = lhef
 simulate (ee)
 \end{Verbatim}
 \end{quote}
 As before, you save this text in a file (named, e.g.,
 \verb|ee.sin|) which is run by
 \begin{verbatim}
 /home/user$ whizard -r ee.sin
 \end{verbatim}
 (We will come to the meaning of the \verb|-r| option later.)
 This produces a lot of output which looks similar to this:
 
  \begin{footnotesize}
  \begin{verbatim}
  | Writing log to 'whizard.log'
 [... banner ...]
  |=============================================================================|
  |                               WHIZARD 2.8.3
  |=============================================================================|
  | Reading model file '/usr/local/share/whizard/models/SM.mdl'
  | Preloaded model: SM
  | Process library 'default_lib': initialized
  | Preloaded library: default_lib
  | Reading commands from file 'ee.sin'
  | Process library 'default_lib': recorded process 'ee'
  sqrts =  3.600000000000E+02
  n_events = 10
  \end{verbatim}
 
  \begin{verbatim}
  | Starting simulation for process 'ee'
  | Simulate: process 'ee' needs integration
  | Integrate: current process library needs compilation
  | Process library 'default_lib': compiling ...
  | Process library 'default_lib': writing makefile
  | Process library 'default_lib': removing old files
  rm -f default_lib.la
  rm -f default_lib.lo default_lib_driver.mod opr_ee_i1.mod ee_i1.lo
  rm -f ee_i1.f90
  | Process library 'default_lib': writing driver
  | Process library 'default_lib': creating source code
  rm -f ee_i1.f90
  rm -f opr_ee_i1.mod
  rm -f ee_i1.lo
  /usr/local/bin/omega_SM.opt -o ee_i1.f90 -target:whizard
   -target:parameter_module parameters_SM -target:module opr_ee_i1
   -target:md5sum '70DB728462039A6DC1564328E2F3C3A5' -fusion:progress
   -scatter 'e- e+ -> mu- mu+'
  [1/1] e- e+ -> mu- mu+ ... allowed. [time: 0.00 secs, total: 0.00 secs, remaining: 0.00 secs]
  all processes done. [total time: 0.00 secs]
  SUMMARY: 6 fusions, 2 propagators, 2 diagrams
  | Process library 'default_lib': compiling sources
 [.....]
  \end{verbatim}
 
 
  \begin{verbatim}
  | Process library 'default_lib': loading
  | Process library 'default_lib': ... success.
  | Integrate: compilation done
  | RNG: Initializing TAO random-number generator
  | RNG: Setting seed for random-number generator to 9616
  | Initializing integration for process ee:
  | ------------------------------------------------------------------------
  | Process [scattering]: 'ee'
  |   Library name  = 'default_lib'
  |   Process index = 1
  |   Process components:
  |     1: 'ee_i1':   e-, e+ => mu-, mu+ [omega]
  | ------------------------------------------------------------------------
  | Beam structure: [any particles]
  | Beam data (collision):
  |   e-  (mass = 5.1099700E-04 GeV)
  |   e+  (mass = 5.1099700E-04 GeV)
  |   sqrts = 3.600000000000E+02 GeV
  | Phase space: generating configuration ...
  | Phase space: ... success.
  | Phase space: writing configuration file 'ee_i1.phs'
  | Phase space: 2 channels, 2 dimensions
  | Phase space: found 2 channels, collected in 2 groves.
  | Phase space: Using 2 equivalences between channels.
  | Phase space: wood
  Warning: No cuts have been defined.
  \end{verbatim}
 
 
  \begin{verbatim}
  | Starting integration for process 'ee'
  | Integrate: iterations not specified, using default
  | Integrate: iterations = 3:1000:"gw", 3:10000:""
  | Integrator: 2 chains, 2 channels, 2 dimensions
  | Integrator: Using VAMP channel equivalences
  | Integrator: 1000 initial calls, 20 bins, stratified = T
  | Integrator: VAMP
  |=============================================================================|
  | It      Calls  Integral[fb]  Error[fb]   Err[%]    Acc  Eff[%]   Chi2 N[It] |
  |=============================================================================|
     1        784  8.3282892E+02  1.68E+00    0.20    0.06*  39.99
     2        784  8.3118961E+02  1.23E+00    0.15    0.04*  76.34
     3        784  8.3278951E+02  1.36E+00    0.16    0.05   54.45
  |-----------------------------------------------------------------------------|
     3       2352  8.3211789E+02  8.01E-01    0.10    0.05   54.45    0.50   3
  |-----------------------------------------------------------------------------|
     4       9936  8.3331732E+02  1.22E-01    0.01    0.01*  54.51
     5       9936  8.3341072E+02  1.24E-01    0.01    0.01   54.52
     6       9936  8.3331151E+02  1.23E-01    0.01    0.01*  54.51
  |-----------------------------------------------------------------------------|
     6      29808  8.3334611E+02  7.10E-02    0.01    0.01   54.51    0.20   3
  |=============================================================================|
  \end{verbatim}
 
  \begin{verbatim}
 [.....]
 | Simulate: integration done
 | Simulate: using integration grids from file 'ee_m1.vg'
 | RNG: Initializing TAO random-number generator
 | RNG: Setting seed for random-number generator to 9617
 | Simulation: requested number of events = 10
 |             corr. to luminosity [fb-1] =   1.2000E-02
 | Events: writing to LHEF file 'ee.lhe'
 | Events: writing to raw file 'ee.evx'
 | Events: generating 10 unweighted, unpolarized events ...
 | Events: event normalization mode '1'
 |         ... event sample complete.
 | Events: closing LHEF file 'ee.lhe'
 | Events: closing raw file 'ee.evx'
 | There were no errors and    1 warning(s).
 | WHIZARD run finished.
 |=============================================================================|
  \end{verbatim}
  \end{footnotesize}
 %$
 The final result is the desired event file, \ttt{ee.lhe}.
 
 Let us discuss the output quickly to walk you through the procedures
 of a \whizard\ run: after the logfile message and the banner, the
 reading of the physics model and the initialization of a process
 library, the recorded process with tag \ttt{'ee'} is recorded. Next,
 user-defined parameters like the center-of-mass energy and the number
 of demanded (unweighted) events are displayed. As a next step,
 \whizard\ is starting the simulation of the process with tag
 \ttt{'ee'}. It recognizes that there has not yet been an integration
 over phase space (done by an optional \ttt{integrate} command,
 cf. Sec.~\ref{sec:integrate}), and consequently starts the
 integration. It then acknowledges, that the process code for the
 process \ttt{'ee'} needs to be compiled first (done by an optional
 \ttt{compile} command, cf. Sec.~\ref{sec:compilation}). So, \whizard\
 compiles the process library, writes the makefile for its steering,
 and as a safeguard against garbage removes possibly existing
 files. Then, the source code for the library and its processes are
 generated: for the process code, the default method -- the matrix
 element generator \oMega\ is called (cf. Sec.~\ref{sec:omega_me}); and
 the sources are being compiled.
 
 The next steps are the loading of the process library, and \whizard\
 reports the completion of the integration. For the Monte-Carlo
 integration, a random number generator is initialized. Here, it is the
 default generator, TAO (for more details, cf. Sec.~\ref{sec:tao},
 while the random seed is set to a value initialized by the system
 clock, as no seed has been provided in the \sindarin\ input file.
 
 Now, the integration for the process \ttt{'ee'} is initialized, and
 information about the process (its name, the name of its process
 library, its index inside the library, and the process components out
 of which it consists, cf. Sec.~\ref{sec:processcomp}) are
 displayed. Then, the beam structure is shown, which in that case are
 symmetric partonic electron and positron beams with the center-of-mass
 energy provided by the user (360 GeV). The next step is the generation
 of the phase space, for which the default phase space method
 \ttt{wood} (for more details cf. Sec.~\ref{sec:wood}) is selected. The
 integration is performed, and the result with absolute and relative
 error, unweighting efficiency, accuracy, $\chi^2$ quality is shown.
 
 The final step is the event generation
 (cf. Chap.~\ref{chap:events}). The integration grids are now being
 used, again the random number generator is initialized. Finally, event
 generation of ten unweighted events starts (\whizard\ let us know to
 which integrated luminosity that would correspond), and events are
 written both in an internal (binary) event format as well as in the
 demanded LHE format. This concludes the \whizard\ run.
 
 After a more comprehensive introduction into the \sindarin\ steering
 language in the next chapter, Chap.~\ref{chap:sindarinintro}, we will
 discuss all the details of the different steps of this introductory
 example.
 
 
 \clearpage
 
 \section{WHIZARD in a Computing Environment}
 
 \subsection{Working on a Single Computer}
 \label{sec:workspace}
 
 After installation, \whizard\ is ready for use.  There is a slight
 complication if \whizard\ has been installed in a location that is not
 in your standard search paths.
 
 In that case, to successfully run \whizard, you may either
 \begin{itemize}
 \item
   manually add \ttt{your-install-directory/bin} to your execution PATH\\
   and \ttt{your-install-directory/lib} to your library search path
   (LD\_LIBRARY\_PATH), or
 \item
   whenever you start a project, execute
   \begin{interaction}
     your-workspace> . your-install-directory/bin/whizard-setup.sh
   \end{interaction}
   which will enable the paths in your current environment, or
 \item
   source \ttt{whizard-setup.sh} script in your shell startup file.
 \end{itemize}
 In either case, try to call \ttt{whizard --help} in order to check
 whether this is done correctly.
 
 For a new \whizard\ project, you should set up a new (empty)
 directory.  Depending on the complexity of your task, you may want to
 set up separate directories for each subproblem that you want to
 tackle, or even for each separate run.  The location of the
 directories is arbitrary.
 
 To run, \whizard\ needs only a single input file, a \sindarin\ command
 script with extension \ttt{.sin} (by convention).  Running
 \whizard\ is as simple as
 \begin{interaction}
   your-workspace> whizard your-input.sin
 \end{interaction}
 No other configuration files are needed.  The total number of
 auxiliary and output files generated in a single run may get quite
 large, however, and they may clutter your workspace.  This is the
 reason behind keeping subdirectories on a per-run basis.
 
 Basic usage of \whizard\ is explained in Chapter~\ref{chap:start}, for
 more details, consult the following chapters.  In
 Sec.~\ref{sec:cmdline-options} we give an account of the command-line
 options that \whizard\ accepts.
 
 \subsection{Working Parallel on Several Computers}
 \label{sec:mpi}
 
 For integration (only VAMP2), \whizard\ supports parallel execution via MPI
 by communicating between parallel tasks on a single machine or distributed over
 several machines.
 
 During integration the calculation of channels is distributed along several
 workers where a master worker collects the results and adapts weights and grids.
 In wortwhile cases (e.g. high number of calls in one channel), the calculation
 of a single grid is distributed.
 
 In order to use these advancements, \whizard\ requires an installed MPI-3.1 capable
 library (e.g. OpenMPI) and configuration and compilation with the appropriate flags,
 cf.~Sec.~\ref{sec:installation}.
 
 MPI support is only active when the integration method is set to VAMP2.
 Additionally, to preserve the numerical properties of a single task run, it is
 recommended to use the RNGstream as random number generator.
 \begin{code}
   $integration_method = 'vamp2'
   $rng_method = 'rng_stream'
 \end{code}
 
 \whizard\ has then to be called by mpirun
 \begin{footnotesize}
 \begin{Verbatim}[frame=single]
   your-workspace> mpirun -f hostfile -np 4 --output-filename mpi.log whizard your-input.sin
 \end{Verbatim}
 \end{footnotesize}
 where the number of parallel tasks can be set by \ttt{-np} and a hostfile can be
 given by \ttt{--hostfile}. It is recommended to use \ttt{--output-filename} which
 lets mpirun redirect the standard (error) output to a file, for each worker separatly.
 
 \subsubsection{Notes on Parallelization with MPI}
 
 The parallelization of \whizard\ requires that all instances of the
 parallel run be able to write and read all files by produced
 \whizard\ in a network file system as the current implementation does
 not handle parallel I/O. Usually, high-performance clusters have
 support for at least one network filesystem.
 
 Furthermore, not all functions of \whizard\ are currently supported or
 are only supported in a limited way in parallel mode. Currently the
 \verb|?rebuild_<flags>| for the phase space and the matrix element
 library are not yet available, as well as the calculation of matrix
 elements with resonance history.
 
 Some features that have been missing in the very first implementation
 of the parallelized integration have now been made available, like
 the support of run IDs and the parallelization of the event generation.
 
 A final remark on the stability of the numerical results in terms of
 the number of workers involved. Under certain circumstances, results
 between different numbers of workers but using otherwise an identical
 \sindarin\ file can lead to slightly numerically different (but
 statistically compatible) results for integration or event generation
 This is related to the execution of the computational operations in
 MPI, which we use to reduce results from all workers. If the order of
 the numbers in the arithmetical operations changes, for example, by
 different setups of the workers, then the numerical results change
 slightly, which in turn is amplified under the influence of the
 adaptation. Nevertheless, the results are all statistically
 consistent.
 
 \subsection{Stopping and Resuming WHIZARD Jobs}
 
 On a Unix-like system, it is possible to prematurely stop running jobs
 by a \ttt{kill(1)} command, or by entering \ttt{Ctrl-C} on the
 terminal.
 
 If the system supports this, \whizard\ traps these signals.  It also
 traps some signals that a batch operating system might issue, e.g.,
 for exceeding a predefined execution time limit.  \whizard\ tries to
 complete the calculation of the current event and gracefully close
 open files.  Then, the program terminates with a message and a nonzero
 return code.  Usually, this should not take more than a fraction of a
 second.
 
 If, for any reason, the program does not respond to an interrupt, it
 is always possible to kill it by \ttt{kill -9}.  A convenient method,
 on a terminal, would be to suspend it first by \ttt{Ctrl-Z} and then
 to kill the suspended process.
 
 The program is usually able to recover after being stopped.  Simply
 run the job again from start, with the same input, all output files
 generated so far left untouched.  The results obtained so far will be
 quickly recovered or gathered from files written in the previous run,
 and the actual time-consuming calculation is resumed near the point
 where it was interrupted.\footnote{This holds for simple workflow.  In
   case of scans and repeated integrations of the same process, there
   may be name clashes on the written files which prevent resuming.  A
   future \whizard\ version will address this problem.}  If the
 interruption happened during an integration step, it is resumed after
 the last complete iteration.  If it was during event generation, the
 previous events are taken from file and event generation is continued.
 
 The same mechanism allows for efficiently redoing a calculation with
 similar, somewhat modified input.  For instance, you might want to add
 a further observable to event analysis, or write the events in a
 different format.  The time for rerunning the program is determined
 just by the time it takes to read the existing integration or event
 files, and the additional calculation is done on the recovered
 information.
 
 By managing various checksums on its input and output files, \whizard\
 detects changes that affect further calculations, so it does a
 real recalculation only where it is actually needed.  This applies to
 all steps that are potentially time-consuming: matrix-element code
 generation, compilation, phase-space setup, integration, and event
 generation.  If desired, you can set command-line options or
 \sindarin\ parameters that explicitly discard previously generated
 information.
 
 
 \subsection{Files and Directories: default and customization}
 
 \whizard\ jobs take a small set of files as input.  In many cases, this is
 just a single \sindarin\ script provided by the user.
 When running, \whizard\ can produce a set of auxiliary and output files:
 \begin{enumerate}
 \item
   \textbf{Job.}
   Files pertaining to the \whizard\ job as a whole.  This is the default log
   file \ttt{whizard.log}.
 \item
   \textbf{Process compilation.}  Files that originate from generating and
   compiling process code.  If the default \oMega\ generator is used, these
   files include Fortran source code as well as compiled libraries that are
   dynamically linked to the running executable.  The file names are derived
   from either the process-library name or the individual process names, as
   defined in the \sindarin\ input.  The default library name is
   \ttt{default\_lib}.
 \item
   \textbf{Integration.}
   Files that are created by integration, i.e., when calculating the total cross
   section for a scattering process using the Monte-Carlo algorithm.  The file
   names are derived from the process name.
 \item
   \textbf{Simulation.}
   Files that are created during simulation, i.e., generating event samples for
   a process or a set of processes.  By default, the file names are derived
   from the name of the first process.  Event-file formats are distinguished
   by appropriate file name extensions.
 \item
   \textbf{Result Analysis.}
   Files that are created by the internal analysis tools and written by the
   command \ttt{write\_analysis} (or \ttt{compile\_analysis}).  The default
   base name is \ttt{whizard\_analysis}.
 \end{enumerate}
 
 A complex workflow with several processes, parameter sets, or runs, can easily
 lead to in file-name clashes or a messy working directory.  Furthermore,
 running a batch job on a dedicated computing environment often requires
 transferring data from a user directory to the server and back.
 
 Custom directory and file names can be used to organize things and facilitate
 dealing with the environment, along with the available batch-system tools for
 coordinating file transfer.
 \begin{enumerate}
 \item
   \textbf{Job.}
   \begin{itemize}
   \item
     The \ttt{-L} option on the command line defines a custom base name for
     the log file.
   \item
     The \ttt{-J} option on the command line defines a job ID.  For instance,
     this may be set to the job ID assigned by the batch system.  Within the
     \sindarin\ script, the job ID is available as the string variable
     \ttt{\$job\_id} and can be used for constructing custom job-specific file
     and directory names, as described below.
   \end{itemize}
 \item
   \textbf{Process compilation.}
   \begin{itemize}
   \item
     The user can require the program to put all files created during the
     compilation step including the library to be linked, in a subdirectory of
     the working directory.  To enable this, set the string variable
     \ttt{\$compile\_workspace} within the \sindarin\ script.
   \end{itemize}
 \item
   \textbf{Integration.}
   \begin{itemize}
   \item
     The value of the string variable \ttt{\$run\_id}, if set, is appended to
     the base name of all files created by integration, separated by dots.  If
     the \sindarin\ script scans over parameters, varying the run ID avoids
     repeatedly overwriting files with identical name during the scan.
   \item
     The user can require the program to put the important files created during
     the integration step -- the phase-space configuration file and the
     \vamp\ grid files -- in a subdirectory of the working directory.  To
     enable this, set the string variable \ttt{\$integrate\_workspace} within
     the \sindarin\ script.  (\ttt{\$compile\_workspace} and
     \ttt{\$integrate\_workspace} may be set to the same value.)
   \end{itemize}
   Log files produced during the integration step are put in the working
   directory.
 \item
   \textbf{Simulation.}
   \begin{itemize}
   \item
     The value of the string variable \ttt{\$run\_id}, if set, identifies
     the specific integration run that is used for the event sample.  It is
     also inserted into default event-sample file names.
   \item
     The variable \ttt{\$sample}, if set, defines an arbitrary base name for the
     files related to the event sample.
   \end{itemize}
   Files resulting from simulation are put in the working directory.
 \item
   \textbf{Result Analysis.}
   \begin{itemize}
   \item
     The variable \ttt{\$out\_file}, if set,
     defines an arbitrary base name for the analysis data and
     auxiliary files.
   \end{itemize}
   Files resulting from result analysis are put in the working directory.
 \end{enumerate}
 
 
 \subsection{Batch jobs on a different machine}
 
 It is possible to separate the tasks of process-code compilation, integration,
 and simulation, and execute them on different machines.  To make use of
 this feature, the local and remote machines including all
 installed libraries that are relevant for \whizard, must be
 binary-compatible.
 \begin{enumerate}
 \item
   Process-code compilation may be done once on a local machine, while the
   time-consuming tasks of integration and event generation for specific
   parameter sets are delegated to a remote machine, e.g., a batch cluster.  To
   enable this, prepare a \sindarin\ script that just produces process code
   (i.e., terminates with a \ttt{compile} command) for the local machine.  You
   may define \ttt{\$compile\_workspace} such that all generated code
   conveniently ends up in a single subdirectory.
 
   To start the batch job, transfer the workspace subdirectory to the remote
   machine
   and start \whizard\ there.  The \sindarin\ script on the remote machine must
   include the local script unchanged in all parts that are relevant for
   process definition.  The program will recognize the contents of the
   workspace, skip compilation and instead link the process library immediately.
   To proceed further, the script should define the run-specific parameters and
   contain the appropriate commands for integration and simulation.
 \item
   Analogously, you may execute both process-code compilation and integration
   locally, but generate event samples on a remote machine.  To this end,
   prepare a \sindarin\ script that produces process code and computes integrals
   (i.e., terminates with an \ttt{integrate} command) for the local machine.
   You may define \ttt{\$compile\_workspace} and \ttt{\$integrate\_workspace}
   (which may coincide) such that all generated code, phase-space and
   integration grid data conveniently end up in subdirectories.
 
   To start the batch job, transfer the workspace(s) to the remote machine and
   start \whizard\ there.  The \sindarin\ script on the remote machine must
   include the local script unchanged in all parts that are relevant for
   process definition and integration.  The program will recognize the contents
   of the workspace, skip compilation and integration and instead load the
   process library and integration results immediately.  To proceed further,
   the script should define the sample-specific parameters and contain the
   appropriate commands for simulation.
 \end{enumerate}
 
 To simplify transferring whole directories, \whizard\ supports the
 \ttt{--pack} and \ttt{--unpack} options.  You may specify any number of these
 options for a \whizard\ run.  (The feature relies on the GNU version of the
 \ttt{tar} utility.)
 
 For instance,
 \begin{code}
 whizard script1.sin --pack my_ws
 \end{code}
 runs \whizard\ with the \sindarin\ script \ttt{script1.sin} as input, where
 within the script you have defined
 \begin{code}
 $compile_workspace = "my_ws"
 \end{code}
 as the target directory for process-compilation files.  After completion, the
 program will tar and gzip the target directory as \ttt{my\_ws.tgz}.  You
 should copy this file to the remote machine as one of the job's input files.
 
 On the remote machine, you can then run the program with
 \begin{code}
 whizard script2.sin --unpack my_ws.tgz
 \end{code}
 where \ttt{script2.sin} should include \ttt{script1.sin}, and add integration
 or simulation commands.  The contents of \ttt{ws.tgz} will thus be unpacked
 and reused on the remote machine, instead of generating new process code.
 
 
 
 \subsection{Static Linkage}
 
 In its default running mode, \whizard\ compiles process-specific matrix
 element code on the fly and dynamically links the resulting library.  On the
 computing server, this requires availability of the appropriate Fortran
 compiler, as well as the \ocaml\ compiler suite, and the dynamical linking
 feature.
 
 Since this may be unavailable or undesired, there is a possibility to
 distribute \whizard\ as a statically linked executable that contains a
 pre-compiled library of processes.  This removes the need for the Fortran
 compiler, the \ocaml\ system, and extra dynamic linking.  Any external
 libraries that are accessed (the \fortran\ runtime environment, and possibly
 some dynamically linked external libraries and/or the C++ runtime library,
 must still be available on the target system, binary-compatible.  Otherwise,
 there is no need for transferring the complete \whizard\ installation or
 process-code compilation data.
 
 Generating, compiling and linking matrix element code is done in advance on a
 machine that can access the required tools and produces compatible libraries.
 This procedure is accomplished by \sindarin\ commands, explained below in
 Sec.~\ref{sec:static}.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \newpage
 
 \section{Troubleshooting}
 \label{sec:troubleshooting}
 
 In this section, we list known issues or problems and give advice on
 what can be done in case something does not work as intended.
 
 \subsection{Possible (uncommon) build problems}
 \label{sec:buildproblems}
 
 \subsubsection{\ocaml\ versions and \oMega\ builds}
 
 For the matrix element generator \oMega\ of \whizard\, the functional
 programming language \ocaml\ is used. Unfortunately, the versions of
 the \ocaml\ compiler from 3.12.0 on broke backwards
 compatibility. Therefore,  versions of \oMega/\whizard\ up to v2.0.2
 only compile with older versions (3.04 to 3.11 works). This has been
 fixed in all \whizard\ versions from 2.0.3 on.
 
 \subsubsection{Identical Build and Source directories}
 
 There is a problem that only occurred with version 2.0.0 and has been
 corected for all follow-up versions. It can only appear if you
 compile the \whizard\ sources in the source directory. Then an error
 like this may occur:
 \begin{footnotesize}
 \begin{Verbatim}[frame=single]
 ...
 libtool: compile:  gfortran -I../misc -I../vamp -g -O2 -c processes.f90 -fPIC -o
           .libs/processes.o
 libtool: compile:  gfortran -I../misc -I../vamp -g -O2 -c processes.f90 -o
           processes.o >/dev/null 2>&1
 make[2]: *** No rule to make target `limits.lo', needed by `decays.lo'.  Stop.
 ...
 make: *** [all-recursive] Error 1
 \end{Verbatim}
 \end{footnotesize}
 In this case, please unpack a fresh copy of \whizard\ and configure it
 in a separate directory (not necessarily a subdirectory). Then the
 compilation will go through:
 \begin{footnotesize}
 \begin{Verbatim}[frame=single]
 $ zcat whizard-2.0.0.tar.gz | tar xf -
 $ cd whizard-2.0.0
 $ mkdir _build
 $ cd _build
 $ ../configure FC=gfortran
 $ make
 \end{Verbatim}
 \end{footnotesize}
 The developers use this setup to be able to test different
 compilers. Therefore building in the same directory is not as
 thoroughly tested. This behavior has been patched from version 2.0.1
 on. But note that in general it is always adviced to keep
 build and source directory apart from each other.
 
 %%%%%
 
 \subsection{What happens if \whizard\ throws an error?}
 \label{ref:errors}
 
 \subsubsection{Particle name special characters in process
   declarations}
 
 Trying to use a process declaration like
 \begin{code}
 process foo = e-, e+ => mu-, mu+
 \end{code}
 will lead to a \sindarin\ syntax error:
 \begin{Code}
 process foo = e-, e+ => mu-, mu+
                ^^
 | Expected syntax: SEQUENCE    <cmd_process> = process <process_id> '=' <process_p
 | Found token: KEYWORD:    '-'
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR:  Syntax error (at or before the location indicated above)
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 \whizard\ tries to interpret the minus and plus signs as operators
 (\ttt{KEYWORD: '-'}), so you have to quote the particle names:
 \ttt{process foo = "e-", "e+" => "mu-", "mu+"}.
 
 
 \subsubsection{Missing collider energy}
 
 This happens if you forgot to set the collider energy in the
 integration of a scattering process:
 \begin{Code}
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR:  Colliding beams: sqrts is zero (please set sqrts)
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 This will solve your problem:
 \begin{code}
 sqrts = <your_energy>
 \end{code}
 
 \subsubsection{Missing process declaration}
 
 If you try to integrate or simulate a process that has not declared
 before (and is also not available in a library that might be loaded),
 \whizard\ will complain:
 \begin{Code}
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Process library doesn't contain process 'f00'
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 Note that this could sometimes be a simple typo, e.g. in that case an
 \ttt{integrate (f00)} instead of \ttt{integrate (foo)}
 
 \subsubsection{Ambiguous initial state without beam declaration}
 
 When the user declares a process with a flavor sum in the initial
 state, e.g.
 \begin{code}
 process qqaa = u:d, U:D => A, A
 sqrts = <your_energy>
 integrate (qqaa)
 \end{code}
 then a fatal error will be issued:
 \begin{Code}
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Setting up process 'qqaa':
 ***                 --------------------------------------------
 ***              Inconsistent initial state. This happens if either
 ***              several processes with non-matching initial states
 ***              have been added, or for a single process with an
 ***              initial state flavor sum. In that case, please set beams
 ***              explicitly [singling out a flavor / structure function.]
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 What now? Either a structure function providing a tensor structure in
 flavors has to be provided like
 \begin{code}
 beams = p, pbar => pdf_builtin
 \end{code}
 or, if the partonic process was intended, a specific flavor has to be
 singled out,
 \begin{code}
 beams = u, U
 \end{code}
 which would take only the up-quarks. Note that a sum over process
 components with varying initial states is not possible.
 
 \subsubsection{Invalid or unsupported beam structure}
 
 An error message like
 \begin{Code}
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Beam structure: [.......] not supported
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 This happens if you try to use a beam structure with is either not
 supported by \whizard\ (meaning that there is no phase-space
 parameterization for Monte-Carlo integration available in order to
 allow an efficient sampling), or you have chosen a combination of beam
 structure functions that do not make sense physically. Here is an
 example for the latter (lepton collider ISR applied to protons, then
 proton PDFs):
 \begin{code}
 beams = p, p => isr => pdf_builtin
 \end{code}
 
 \subsubsection{Mismatch in beams}
 
 Sometimes you get a rather long error output statement followed by a
 fatal error:
 \begin{Code}
  Evaluator product
  First interaction
  Interaction: 6
  Virtual:
  Particle 1
   [momentum undefined]
 [.......]
  State matrix:  norm =  1.000000000000E+00
  [f(2212)]
    [f(11)]
      [f(92) c(1 )]
        [f(-6) c(-1 )] => ME(1) = ( 0.000000000000E+00, 0.000000000000E+00)
 [.......]
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Product of density matrices is empty
 ***                 --------------------------------------------
 ***              This happens when two density matrices are convoluted
 ***              but the processes they belong to (e.g., production
 ***              and decay) do not match. This could happen if the
 ***              beam specification does not match the hard
 ***              process. Or it may indicate a WHIZARD bug.
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 As \whizard\ indicates, this could have happened because the hard
 process setup did not match the specification of the beams as in:
 \begin{code}
 process neutral_current_DIS = e1, u => e1, u
 beams_momentum = 27.5 GeV, 920 GeV
 beams = p, e => pdf_builtin, none
 integrate (neutral_current_DIS)
 \end{code}
 In that case, the order of the beam particles simply was wrong,
 exchange proton and electron (together with the structure functions)
 into \ttt{beams = e, p => none, pdf\_builtin}, and \whizard\ will be
 happy.
 
 \subsubsection{Unstable heavy beam particles}
 
 If you try to use unstable particles as beams that can potentially
 decay into the final state particles, you might encounter the
 following error message:
 \begin{Code}
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR:  Phase space: Initial beam particle can decay
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 This happens basically only for  processes in testing/validation (like
 $t \bar t \to b \bar b$). In principle, it could also happen in a real
 physics setup, e.g. when simulating electron pairs at a muon collider:
 \begin{code}
 process mmee = "mu-", "mu+" => "e-", "e+"
 \end{code}
 However, \whizard\ at the moment does not allow a muon width, and so
 \whizard\ is not able to decay a muon in a scattering process.
 A possibile decay of the beam particle into (part of) the final state
 might lead to instabilities in the phase space setup. Hence, \whizard\
 do not let you perform such an integration right away. When you
 nevertheless encounter such a rare occasion in your setup, there is a
 possibility to convert this fatal error into a simple warning by
 setting the flag:
 \begin{code}
 ?fatal_beam_decay = false
 \end{code}
 
 \subsubsection{Impossible beam polarization}
 
 If you specify a beam polarization that cannot correspond to any
 physically allowed spin density matrix, e.g.,
 \begin{code}
 beams = e1, E1
 beams_pol_density = @(-1), @(1:1:.5, -1, 1:-1)
 \end{code}
 \whizard\ will throw a fatal
 error like this:
 \begin{Code}
  Trace of matrix square =    1.4444444444444444
  Polarization: spin density matrix
    spin type     = 2
    multiplicity  = 2
    massive       = F
    chirality     = 0
    pol.degree    = 1.0000000
    pure state    = F
    @(+1: +1: ( 3.333333333333E-01, 0.000000000000E+00))
    @(-1: -1: ( 6.666666666667E-01, 0.000000000000E+00))
    @(-1: +1: ( 6.666666666667E-01, 0.000000000000E+00))
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Spin density matrix: not permissible as density matrix
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 
 \subsubsection{Beams with crossing angle}
 
 Specifying a crossing angle (e.g. at a linear lepton collider) without
 explicitly setting the beam momenta,
 \begin{code}
   sqrts = 1 TeV
   beams = e1, E1
   beams\_theta = 0, 10 degree
 \end{code}
 triggers a fatal:
 \begin{Code}
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Beam structure: angle theta/phi specified but momentum/a p undefined
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 In that case the single beam momenta have to be explicitly set:
 \begin{code}
   beams = e1, E1
   beams\_momentum = 500 GeV, 500 GeV
   beams\_theta = 0, 10 degree
 \end{code}
 
 \subsubsection{Phase-space generation failed}
 
 Sometimes an error might be issued that \whizard\ could not generate a
 valid phase-space parameterization:
 \begin{Code}
 | Phase space: ... failed.  Increasing phs_off_shell ...
 | Phase space: ... failed.  Increasing phs_off_shell ...
 | Phase space: ... failed.  Increasing phs_off_shell ...
 | Phase space: ... failed.  Increasing phs_off_shell ...
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Phase-space: generation failed
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 You see that \whizard\ tried to increase the number of off-shell lines
 that are taken into account for the phase-space setup. The second most
 important parameter for the phase-space setup, \ttt{phs\_t\_channel},
 however, is not increased automatically. Its default value is $6$, so
 e.g. for the process $e^+ e^- \to 8\gamma$ you will run into the
 problem above. Setting
 \begin{code}
 phs_off_shell = <n>-1
 \end{code}
 where \ttt{<n>} is the number of final-state particles will solve the problem.
 
 \subsubsection{Non-converging process integration}
 
 There could be several reasons for this to happen. The most prominent
 one is that no cuts have been specified for the process (\whizard\ttt{2}
 does not apply default cuts), and there are singular regions in the
 phase space over which the integration stumbles. If cuts have been
 specified, it could be that they are not sufficient. E.g. in $pp \to
 jj$ a distance cut between the two jets prevents singular collinear
 splitting in their generation, but if no $p_T$ cut have been set,
 there is still singular collinear splitting from the beams.
 
 \subsubsection{Why is there no event file?}
 
 If no event file has been generated, \whizard\ stumled over some error
 and should have told you, or, you simply forgot to set a \ttt{simulate}
 command for your process. In case there was a \ttt{simulate} command
 but the process under consideration is not possible (e.g. a typo,
 \ttt{e1, E1 => e2, E3} instead of \ttt{e1, E1 => e3, E3}), then you
 get an error like that:
 \begin{Code}
 ******************************************************************************
 *** ERROR: Simulate: no process has a valid matrix element.
 ******************************************************************************
 \end{Code}
 
 \subsubsection{Why is the event file empty?}
 
 In order to get events, you need to set either a desired number of
 events:
 \begin{code}
 n_events = <integer>
 \end{code}
 or you have to specify a certain integrated luminosity (the default
 unit being inverse femtobarn:
 \begin{code}
 luminosity = <real> / 1 fbarn
 \end{code}
 In case you set both, \whizard\ will take the one that leads to the
 higher number of events.
 
 \subsubsection{Parton showering fails}
 
 For BSM models containing massive stable or long-lived particles
 parton showering with \pythiasix\ fails:
 \begin{Code}
      Advisory warning type 3 given after        0 PYEXEC calls:
      (PYRESD:) Failed to decay particle  1000022 with mass   15.000
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Simulation: failed to generate valid event after 10000 tries
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 The solution to that problem is discussed in Sec.~\ref{sec:pythia6}.
 
 \vspace{1cm}
 
 
 %%%%%
 
 \subsection{Debugging, testing, and validation}
 
 
 \subsubsection{Catching/tracking arithmetic exceptions}
 
 Catching arithmetic exceptions is not automatically supported by
 \fortran\ compilers. In general, flags that cause the compiler to keep
 track of arithmetic exceptions are diminishing the maximally possible
 performance, and hence they should not be used in production
 runs. Hence, we refrained from making these flags a default.
 They can be added using the \ttt{FCFLAGS = {\em <flags>}} settings during
 configuration. For the \ttt{NAG} \fortran\ compiler we use the flags
 \ttt{-C=all -nan -gline} for debugging purposes. For the \ttt{gfortran}
 compilers, the flags \ttt{-ffpe-trap=invalid,zero,overflow} are the
 corresponding debugging flags. For tests, debugging or first sanity
 checks on your setup, you might want to make use of these flags in
 order to track possible numerical exceptions in the produced code.
 Some compilers started to include \ttt{IEEE} exception handling
 support (\ttt{Fortran 2008} status), but we do not use these
 implementations in the \whizard\ code (yet).
 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{Steering WHIZARD: \sindarin\ Overview}
 \label{chap:sindarinintro}
 
 
 \section{The command language for WHIZARD}
 A conventional physics application program gets its data from a set of input
 files.  Alternatively, it is called as a library, so the user has to write his
 own code to interface it, or it combines these two approaches.  \whizard~1 was
 built in this way: there were some input files which were written by the user,
 and it could be called both stand-alone or as an external library.
 
 \whizard~2 is also a stand-alone program.  It comes with its own full-fledged
 script language, called \sindarin.  All interaction between the user and the
 program is done in \sindarin\ expressions, commands, and scripts.  Two main
 reasons led us to this choice:
 \begin{itemize}
 \item
   In any nontrivial physics study, cuts and (parton- or hadron-level) analysis
   are of central importance.  The task of specifying appropriate kinematics
   and particle selection for a given process is well defined, but it is
   impossible to cover all possiblities in a simple format like the cut files
   of \whizard~1.
 
   The usual way of dealing with this problem is to write analysis driver code
   (often in \ttt{C++}), using external libraries for Lorentz algebra etc.  However,
   the overhead of writing correct \ttt{C++} or \ttt{Fortran} greatly blows up problems
   that could be formulated in a few lines of text.
 \item
   While many problems lead to a repetitive workflow (process definition,
   integration, simulation), there are more involved tasks that involve
   parameter scans, comparisons of different processes, conditional execution,
   or writing output in widely different formats.  This is easily done by a
   steering script, which should be formulated in a complete language.
 \end{itemize}
 The \sindarin\ language is built specifically around event analysis, suitably
 extended to support steering, including data types, loops, conditionals, and
 I/O.
 
 It would have been possible to use an established general-purpose language for
 these tasks.  For instance, \ocaml\ which is a functional language would be a
 suitable candidate, and the matrix-element generator \oMega\ is written in that
 language.  Another candidate would be a popular scripting language such as
 PYTHON.
 
 We started to support interfaces for commonly used languages: prime
 examples for \ttt{C}, \ttt{C++}, and PYTHON are found in the
 \ttt{share/interfaces} subdirectory. However, introducing a
 special-purpose language has the three distinct
 advantages: First, it is compiled and executed by the very \ttt{Fortran} code that
 handles data and thus accesses it without interfaces.  Second, it can be
 designed with a syntax especially suited to the task of event handling and
 Monte-Carlo steering, and third, the user is not forced to learn all those
 features of a generic language that are of no relevance to the application he/she
 is interested in.
 
 
 \section{\sindarin\ scripts}
 
 A \sindarin\ script tells the \whizard\ program what it has to do.  Typically,
 the script is contained in a file which you (the user) create.  The file name
 is arbitrary; by convention, it has the extension `\verb|.sin|'.
 \whizard\ takes the file name as its argument on the command line and
 executes the contained script:
 \begin{verbatim}
 /home/user$ whizard script.sin
 \end{verbatim}
 Alternatively, you can call \whizard\ interactively and execute
 statements line by line; we describe this below in Sec.\ref{sec:whish}.
 
 A \sindarin\ script is a sequence of \emph{statements}, similar to the
 statements in any imperative language such as \ttt{Fortran} or
 \ttt{C}.  Examples of statements are commands like \ttt{integrate},
 variable declarations like \ttt{logical ?flag} or assigments like
 \ttt{mH = 130 GeV}.
 
 The script is free-form, i.e., indentation, extra whitespace and
 newlines are syntactically insignificant.  In contrast to most
 languages, there is no statement separator.  Statements simply follow each
 other, just separated by whitespace.
 \begin{code}
 statement1 statement2
 statement3
                statement4
 \end{code}
 Nevertheless, for clarity we recommend to
 write one statement per line where possible, and to use proper
 indentation for longer statements, nested and bracketed expressions.
 
 A command may consist of a \emph{keyword}, a list of \emph{arguments} in
 parantheses \ttt{(}\ldots\ttt{)}, and an \emph{option} script which
 itself is a sequence of statements.
 \begin{code}
 command
 command_with_args (arg1, arg2)
 command_with_option { option }
 command_with_options (arg) {
   option_statement1
   option_statement2
 }
 \end{code}
 As a rule, parentheses \ttt{()} enclose arguments and expressions, as
 you would expect.  Arguments enclosed in square brackets \ttt{[]} also
 exist.  They have a special meaning, they denote subevents
 (collections of momenta) in event analysis.  Braces \ttt{\{\}} enclose
 blocks of \sindarin\ code.  In particular, the option script
 associated with a command is a block of code that may contain local
 parameter settings, for instance.  Braces always indicate a scoping
 unit, so parameters will be restored their previous values when the
 execution of that command is completed.
 
 The script can contain comments.   Comments are initiated by either a \verb|#|
 or a \verb|!| character and extend to the end of the current line.
 \begin{code}
 statement
 # This is a comment
 statement  ! This is also a comment
 \end{code}
 
 
 %%%%%%%%%%%%%%%
 
 \section{Errors}
 \label{sec:errors}
 
 Before turning to proper \sindarin\ syntax, let us consider error messages.
 \sindarin\ distinguishes syntax errors and runtime errors.
 
 Syntax errors are recognized when the script is read and compiled,
 before any part is executed.  Look at this example:
 \begin{code}
 process foo = u, ubar => d, dbar
 md = 10
 integrade (foo)
 \end{code}
 \whizard\ will fail with the error message
 \begin{interaction}
 sqrts = 1 TeV
 integrade (foo)
           ^^
 | Expected syntax: SEQUENCE    <cmd_num> = <var_name> '=' <expr>
 | Found token: KEYWORD:    '('
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR:  Syntax error (at or before the location indicated above)
 ******************************************************************************
 ******************************************************************************
 WHIZARD run aborted.
 \end{interaction}
 which tells you that you have misspelled the command
 \verb|integrate|, so the compiler tried to interpret it as a variable.
 
 Runtime errors are categorized by their severity.  A warning is simply
 printed:
 \begin{interaction}
 Warning: No cuts have been defined.
 \end{interaction}
 This indicates a condition that is suspicious, but may actually be
 intended by the user.
 
 When an error is encountered, it is printed with more emphasis
 \begin{interaction}
 ******************************************************************************
 *** ERROR: Variable 'md' set without declaration
 ******************************************************************************
 \end{interaction}
 and the program tries to continue.  However, this usually indicates
 that there is something wrong.  (The $d$ quark is defined
 massless, so \verb|md| is not a model parameter.)  \whizard\ counts
 errors and warnings and tells you at the end
 \begin{interaction}
 | There were  1 error(s) and no warnings.
 \end{interaction}
 just in case you missed the message.
 
 Other errors are considered fatal, and execution stops at this point.
 \begin{interaction}
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR:  Colliding beams: sqrts is zero (please set sqrts)
 ******************************************************************************
 ******************************************************************************
 \end{interaction}
 Here, \whizard\ was unable to do anything sensible. But at least (in
 this case) it told the user what to do to resolve the problem.
 
 %%%%%%%%%%%%%%%
 
 \section{Statements}
 \label{sec:statements}
 
 \sindarin\ statements are executed one by one.  For an overview, we
 list the most common statements in the order in which they typically
 appear in a \sindarin\ script, and quote the basic syntax and simple
 examples.  This should give an impression on the \whizard's
 capabilities and on the user interface.  The list is not complete.
 Note that there are no
 mandatory commands (although an empty \sindarin\ script is not really
 useful).  The details and options are explained in later sections.
 
 \subsection{Process Configuration}
 
 \subsubsection{model}
 \begin{syntax}
 model = \var{model-name}
 \end{syntax}
 This assignment sets or resets the current physics model.  The
 Standard Model is already preloaded, so the \ttt{model} assignment
 applies to non-default models.  Obviously, the model must be known to
 \whizard. Example:
 \begin{code}
 model = MSSM
 \end{code}
 See Sec.~\ref{sec:models}.
 
 \subsubsection{alias}
 \begin{syntax}
 alias \var{alias-name} = \var{alias-definition}
 \end{syntax}
 Particles are specified by their names.   For most particles, there
 are various equivalent names.  Names containing special characters
 such as a \verb|+| sign have to be quoted.  The \ttt{alias} assignment
 defines an alias for a list of particles.  This is useful for setting
 up processes with sums over flavors, cut expressions, and more.  The
 alias name is then used like a simple particle name.  Example:
 \begin{syntax}
 alias jet = u:d:s:U:D:S:g
 \end{syntax}
 See Sec.~\ref{sec:alias}.
 
 
 \subsubsection{process}
 \begin{syntax}
 process \var{tag} = \var{incoming} \verb|=>| \var{outgoing}
 \end{syntax}
 Define a process.  You give the process a name \var{tag} by which it is
 identified later, and specify the incoming and outgoing particles,
 and possibly options.  You can define an arbitrary number of processes
 as long as they are distinguished by their names.  Example:
 \begin{code}
 process w_plus_jets = g, g => "W+", jet, jet
 \end{code}
 See Sec.~\ref{sec:processes}.
 
 
 \subsubsection{sqrts}
 \begin{syntax}
 sqrts = \var{energy-value}
 \end{syntax}
 Define the center-of-mass energy for collision processes.  The default
 setup will assume head-on central collisions of two beams.  Example:
 \begin{code}
 sqrts = 500 GeV
 \end{code}
 See Sec.~\ref{sec:beam-setup}.
 
 
 \subsubsection{beams}
 \begin{syntax}
 beams = \var{beam-particles} \\
 beams = \var{beam-particles} => \var{structure-function-setup}
 \end{syntax}
 Declare beam particles and properties.  The current value of \ttt{sqrts} is
 used, unless specified otherwise.  Example:
 \begin{code}
 beams = u:d:s, U:D:S => lhapdf
 \end{code}
 With options, the assignment allows for
 defining beam structure in some detail.  This includes beamstrahlung and ISR
 for lepton colliders, precise structure function definition for hadron
 colliders, asymmetric beams, beam polarization, and more.  See
 Sec.~\ref{sec:beams}.
 
 
 \subsection{Parameters}
 
 \subsubsection{Parameter settings}
 \begin{syntax}
 \var{parameter} = \var{value} \\
 \var{type} \var{user-parameter} \\
 \var{type} \var{user-parameter} = \var{value}
 \end{syntax}
 Specify a value for a parameter.  There are predefined parameters that affect
 the behavior of a command, model-specific parameters (masses, couplings), and
 user-defined parameters.  The latter have to be declared with a type, which
 may be \ttt{int} (integer), \ttt{real}, \ttt{complex}, \ttt{logical},
 \ttt{string}, or \ttt{alias}.  Logical parameter
 names begin with a question mark, string parameter names with a dollar sign.
 Examples:
 \begin{code}
 mb = 4.2 GeV
 ?rebuild_grids = true
 real mass_sum = mZ + mW
 string $message = "This is a string"
 \end{code}
 % $
 The value need not be a literal, it can be an arbitrary expression of the
 correct type.  See Sec.~\ref{sec:variables}.
 
 
 \subsubsection{read\_slha}
 \begin{syntax}
 read\_slha (\var{filename})
 \end{syntax}
 This is useful only for supersymmetric models: read a parameter file
 in the SUSY Les Houches Accord format.  The file defines parameter
 values and, optionally, decay widths, so this command removes the need
 for writing assignments for each of them.
 \begin{code}
 read_slha ("sps1a.slha")
 \end{code}
 See Sec.~\ref{sec:slha}.
 
 
 \subsubsection{show}
 \begin{syntax}
 show (\var{data-objects})
 \end{syntax}
 Print the current value of some data object.  This includes not just
 variables, but also models, libraries, cuts, etc.  This is rather a
 debugging aid, so don't expect the output to be concise in the latter
 cases.  Example:
 \begin{code}
 show (mH, wH)
 \end{code}
 See Sec.~\ref{sec:I/O}.
 
 
 \subsubsection{printf}
 \begin{syntax}
 printf \var{format-string} (\var{data-objects})
 \end{syntax}
 Pretty-print the data objects according to the given format string.
 If there are no data objects, just print the format string.
 This command is borrowed from the \ttt{C} programming language; it is
 actually an interface to the system's \ttt{printf(3)} function.  The
 conversion specifiers are restricted to \ttt{d,i,e,f,g,s},
 corresponding to the output of integer, real, and string variables.
 Example:
 \begin{code}
 printf "The Higgs mass is %f GeV" (mH)
 \end{code}
 See Sec.~\ref{sec:I/O}.
 
 
 \subsection{Integration}
 
 \subsubsection{cuts}
 \begin{syntax}
 cuts = \var{logical-cut-expression}
 \end{syntax}
 The cut expression is a logical macro expression that is evaluated for each
 phase space point during integration and event generation.  You may construct
 expressions out of various observables that are computed for the (partonic)
 particle content of the current event.  If the expression evaluates to
 \verb|true|, the matrix element is calculated and the event is used.  If it
 evaluates to \verb|false|, the matrix element is set zero and the event is
 discarded. Note that for collisions the expression is evaluated in the
 lab frame, while for decays it is evaluated in the rest frame of the
 decaying particle.  In case you want to impose cuts on a factorized
 process, i.e. a combination of a production process and one or more
 decay processes, you have to use the \ttt{selection} keyword
 instead.
 
 Example for the keyword \ttt{cuts}:
 \begin{code}
 cuts = all Pt > 20 GeV [jet]
   and  all mZ - 10 GeV < M < mZ + 10 GeV [lepton, lepton]
   and  no  abs (Eta) < 2 [jet]
 \end{code}
 See Sec.~\ref{sec:cuts}.
 
 
 \subsubsection{integrate}
 \begin{syntax}
 integrate (\var{process-tags})
 \end{syntax}
 Compute the total cross section for a process.  The command takes into account
 the definition of the process, the beam setup, cuts, and parameters as defined
 in the script.  Parameters may also be specified as options to the command.
 
 Integration is necessary for each process for which you want to know total or
 differential cross sections, or event samples.  Apart from computing a value,
 it sets up and adapts phase space and integration grids that are used in event
 generation.   If you just need an event sample, you can omit an explicit
 \ttt{integrate} command; the \ttt{simulate} command will call it
 automatically.  Example:
 \begin{code}
 integrate (w_plus_jets, z_plus_jets)
 \end{code}
 See Sec.~\ref{sec:integrate}.
 
 \subsubsection{?phs\_only/n\_calls\_test}
 \begin{syntax}
 integrate (\var{process-tag}) \{ ?phs\_only = true  n\_calls\_test = 1000 \}
 \end{syntax}
 These are just optional settings for the \ttt{integrate} command
 discussed just a second ago. The \ttt{?phs\_only = true} (note that
 variables starting with a question mark are logicals) option tells
 \whizard\ to prepare a process for integration, but instead of
 performing the integration, just to generate a phase space
 parameterization. \ttt{n\_calls\_test = <num>} evaluates the sampling
 function for random integration channels and random momenta.  \vamp\
 integration grids are neither generated nor used, so the channel
 selection corresponds to the first integration pass, before any grids
 or channel weights are adapted.  The number of sampling points is
 given by \verb|<num>|. The output contains information about the
 timing, number of sampling points that passed the kinematics
 selection, and the number of matrix-element values that were actually
 evaluated. This command is useful mainly for debugging and
 diagnostics.  Example:
 \begin{code}
 integrate (some_large_process) { ?phs_only = true  n_calls_test = 1000 }
 \end{code}
 (Note that there used to be a separate command
 \ttt{matrix\_element\_test} until version 2.1.1 of \whizard\ which has
 been discarded in order to simplify the \sindarin\ syntax.)
 
 \subsection{Events}
 
 \subsubsection{histogram}
 \begin{syntax}
 histogram \var{tag} (\var{lower-bound}, \var{upper-bound}) \\
 histogram \var{tag} (\var{lower-bound}, \var{upper-bound}, \var{step}) \\
 \end{syntax}
 Declare a histogram for event analysis.  The histogram is filled by an
 analysis expression, which is evaluated once for each event during a
 subsequent simulation step.  Example:
 \begin{code}
 histogram pt_distribution (0, 150 GeV, 10 GeV)
 \end{code}
 See Sec.~\ref{sec:histogram}.
 
 
 \subsubsection{plot}
 \begin{syntax}
 plot \var{tag}
 \end{syntax}
 Declare a plot for displaying data points.  The plot may be filled by an
 analysis expression that is evaluated for each event; this would result in a
 scatter plot.  More likely, you will use this feature for displaying data such
 as the energy dependence of a cross section.  Example:
 \begin{code}
 plot total_cross_section
 \end{code}
 See Sec.~\ref{sec:plot}.
 
 
 \subsubsection{selection}
 \begin{syntax}
 selection = \var{selection-expression}
 \end{syntax}
 The selection expression is a logical macro expression that is evaluated once
 for each event. It is applied to the event record,
 after all decays have been executed (if any). It is therefore intended
 e.g. for modelling detector acceptance cuts etc. For unfactorized
 processes the usage of \ttt{cuts} or \ttt{selection} leads to
 the same results. Events for which the selection expression evaluates
 to false are dropped; they are neither analyzed nor written to any
 user-defined output file. However, the dropped events are written to
 \whizard's native event file. For unfactorized processes it is
 therefore preferable to implement all cuts using the \ttt{cuts}
 keyword for the integration, see \ttt{cuts} above.
 Example:
 \begin{code}
 selection = all Pt > 50 GeV [lepton]
 \end{code}
 The syntax is generically the same as for the \ttt{cuts
 expression}, see Sec.~\ref{sec:cuts}. For more information see also
 Sec.~\ref{sec:analysis}.
 
 
 \subsubsection{analysis}
 \begin{syntax}
 analysis = \var{analysis-expression}
 \end{syntax}
 The analysis expression is a logical macro expression that is evaluated once
 for each event that passes the integration and selection cuts in a
 subsequent simulation step.  The
 expression has type logical in analogy with the cut expression; however, its
 main use will be in side effects caused by embedded \ttt{record} expressions.
 The \ttt{record} expression books a value, calculated from observables
 evaluated for the current event, in one of the predefined histograms or plots.
 Example:
 \begin{code}
 analysis = record pt_distribution (eval Pt [photon])
       and  record mval (eval M [lepton, lepton])
 \end{code}
 See Sec.~\ref{sec:analysis}.
 
 
 \subsubsection{unstable}
 \begin{syntax}
 unstable \var{particle} (\var{decay-channels})
 \end{syntax}
 Specify that a particle can decay, if it occurs in the final state of a
 subsequent simulation step.  (In the integration step, all final-state
 particles are considered stable.)  The decay channels are processes which
 should have been declared before by a \ttt{process} command
 (alternatively, there are options that \whizard\ takes care of this
 automatically; cf. Sec.~\ref{sec:decays}).  They may be
 integrated explicitly, otherwise the \ttt{unstable} command will take care of
 the integration before particle decays are generated.  Example:
 \begin{code}
 unstable Z (z_ee, z_jj)
 \end{code}
 Note that the decay is an on-shell approximation.  Alternatively, \whizard\ is
 capable of generating the final state(s) directly, automatically including the
 particle as an internal resonance together with irreducible background.
 Depending on the physical problem and on the complexity of the matrix-element
 calculation, either option may be more appropriate.
 
 See Sec.~\ref{sec:decays}.
 
 
 \subsubsection{n\_events}
 \begin{syntax}
 n\_events = \var{integer}
 \end{syntax}
 Specify the number of events that a subsequent simulation step should produce.
 By default, simulated events are unweighted.  (Unweighting is done by a
 rejection operation on weighted events, so the usual caveats on event
 unweighting by a numerical Monte-Carlo generator do apply.)  Example:
 \begin{code}
 n_events = 20000
 \end{code}
 See Sec.~\ref{sec:simulation}.
 
 
 \subsubsection{simulate}
 \begin{syntax}
 simulate (\var{process-tags})
 \end{syntax}
 Generate an event sample.  The command allows for analyzing the generated
 events by the \ttt{analysis} expression.  Furthermore, events can be written
 to file in various formats.  Optionally, the partonic events can be showered
 and hadronized, partly using included external (\pythia) or truly
 external programs called by \whizard. Example:
 \begin{code}
 simulate (w_plus_jets) { sample_format = lhef }
 \end{code}
 See Sec.~\ref{sec:simulation} and Chapter~\ref{chap:events}.
 
 
 \subsubsection{graph}
 \begin{syntax}
 graph (\var{tag}) = \var{histograms-and-plots}
 \end{syntax}
 Combine existing histograms and plots into a common graph.  Also
 useful for pretty-printing single histograms or plots.  Example:
 \begin{code}
 graph comparison {
   $title = "$p_T$ distribution for two different values of $m_h$"
 } = hist1 & hist2
 \end{code}
 % $
 See Sec.~\ref{sec:graphs}.
 
 
 \subsubsection{write\_analysis}
 \begin{syntax}
 write\_analysis (\var{analysis-objects})
 \end{syntax}
 Writes out data tables for the specified analysis objects (plots,
 graphs, histograms).  If the argument is empty or absent, write all
 analysis objects currently available.  The tables are
 available for feeding external programs.  Example:
 \begin{code}
 write_analysis
 \end{code}
 See Sec.~\ref{sec:analysis}.
 
 
 \subsubsection{compile\_analysis}
 \begin{syntax}
 compile\_analysis (\var{analysis-objects})
 \end{syntax}
 Analogous to \ttt{write\_analysis}, but the generated data tables are
 processed by \LaTeX\ and \gamelan, which produces Postscript and PDF
 versions of the displayed data.  Example:
 \begin{code}
 compile_analysis
 \end{code}
 See Sec.~\ref{sec:analysis}.
 
 
 
 \section{Control Structures}
 
 Like any complete programming language, \sindarin\ provides means for
 branching and looping the program flow.
 
 \subsection{Conditionals}
 
 \subsubsection{if}
 \begin{syntax}
 if \var{logical\_expression} then \var{statements} \\
 elsif \var{logical\_expression} then \var{statements} \\
 else \var{statements} \\
 endif
 \end{syntax}
 Execute statements conditionally, depending on the value of a logical
 expression. There may be none or multiple \ttt{elsif} branches, and
 the \ttt{else} branch is also optional.  Example:
 \begin{code}
 if (sqrts > 2 * mtop) then
   integrate (top_pair_production)
 else
   printf "Top pair production is not possible"
 endif
 \end{code}
 The current \sindarin\ implementation puts some restriction on the
 statements that can appear in a conditional.  For instance, process
 definitions must be done unconditionally.
 
 \subsection{Loops}
 \subsubsection{scan}
 \begin{syntax}
 scan \var{variable} = (\var{value-list}) \{ \var{statements} \}
 \end{syntax}
 Execute the statements repeatedly, once for each value of the scan
 variable.  The statements are executed in a local context, analogous
 to the option statement list for commands.  The value list is a
 comma-separated list of expressions, where each item evaluates to the
 value that is assigned to \ttt{\var{variable}} for this iteration.
 
 The type of the variable is not restricted to numeric, scans can be
 done for various object types.  For instance, here is a scan over strings:
 \begin{code}
 scan string $str = ("%.3g", "%.4g", "%.5g") { printf $str (mW) }
 \end{code}
 % $
 The output:
 \begin{interaction}
 [user variable] $str = "%.3g"
 80.4
 [user variable] $str = "%.4g"
 80.42
 [user variable] $str = "%.5g"
 80.419
 \end{interaction}
 % $
 For a numeric scan variable in particular, there are iterators that
 implement the usual functionality of \ttt{for} loops.  If the scan
 variable is of type integer, an iterator may take one of the forms
 \begin{syntax}
 \var{start-value} \verb|=>| \var{end-value} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|/+| \var{add-step} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|/-| \var{subtract-step} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|/*| \var{multiplicator} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|//| \var{divisor} \\
 \end{syntax}
 The iterator can be put in place of an expression in the
 \ttt{\var{value-list}}.  Here is an example:
 \begin{code}
 scan int i = (1, (3 => 5), (10 => 20 /+ 4))
 \end{code}
 which results in the output
 \begin{interaction}
 [user variable] i =            1
 [user variable] i =            3
 [user variable] i =            4
 [user variable] i =            5
 [user variable] i =           10
 [user variable] i =           14
 [user variable] i =           18
 \end{interaction}
 [Note that the \ttt{\var{statements}} part of the scan construct may
 be empty or absent.]
 
 For real scan variables, there are even more possibilities for iterators:
 \begin{syntax}
 \var{start-value} \verb|=>| \var{end-value} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|/+| \var{add-step} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|/-| \var{subtract-step} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|/*| \var{multiplicator} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|//| \var{divisor} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|/+/| \var{n-points-linear} \\
 \var{start-value} \verb|=>| \var{end-value} \verb|/*/| \var{n-points-logarithmic} \\
 \end{syntax}
 The first variant is equivalent to \ttt{/+ 1}.  The \ttt{/+} and
 \ttt{/-} operators are intended to add or subtract the given step once
 for each iteration.  Since in floating-point arithmetic this would be
 plagued by rounding ambiguities, the actual implementation first
 determines the (integer) number of iterations from the provided step
 value, then recomputes the step so that the iterations are evenly
 spaced with the first and last value included.
 
 The \ttt{/*} and \ttt{//} operators are analogous.  Here, the initial
 value is intended to be multiplied by the step value once for each
 iteration.  After determining the integer number of iterations, the
 actual scan values will be evenly spaced on a logarithmic scale.
 
 Finally, the \ttt{/+/} and \ttt{/*/} operators allow to specify the
 number of iterations (not counting the initial value) directly.  The
 \ttt{\var{start-value}} and \ttt{\var{end-value}} are always included,
 and the intermediate values will be evenly spaced on a linear
 (\ttt{/+/}) or logarithmic (\ttt{/*/}) scale.
 
 Example:
 \begin{code}
 scan real mh = (130 GeV,
            (140 GeV => 160 GeV /+ 5 GeV),
            180 GeV,
            (200 GeV => 1 TeV /*/ 10))
   {  integrate (higgs_decay) }
 \end{code}
 
 
 \subsection{Including Files}
 \subsubsection{include}
 \begin{syntax}
 include (\var{file-name})
 \end{syntax}
 Include a \sindarin\ script from the specified file.  The contents
 must be complete commands; they are compiled and executed as if they
 were part of the current script.  Example:
 \begin{code}
 include ("default_cuts.sin")
 \end{code}
 
 
 
 
 
 \section{Expressions}
 
 \sindarin\ expressions are classified by their types.  The
 type of an expression is verified when the script is compiled, before
 it is executed.  This provides some safety against simple coding
 errors.
 
 Within expressions, grouping is done using ordinary brackets \ttt{()}.
 For subevent expressions, use square brackets \ttt{[]}.
 
 \subsection{Numeric}
 The language supports the classical numeric types
 \begin{itemize}
 \item
    \ttt{int} for integer: machine-default, usually 32 bit;
 \item
    \ttt{real}, usually \emph{double precision} or 64 bit;
 \item
    \ttt{complex}, consisting of real and imaginary part equivalent to a
    \ttt{real} each.
 \end{itemize}
 \sindarin\ supports arithmetic expressions similar to conventional
 languages.  In arithmetic expressions, the three numeric types can be
 mixed as appropriate.  The computation essentially follows the rules
 for mixed arithmetic in \ttt{Fortran}.  The arithmetic operators are
 \verb|+|, \verb|-|, \verb|*|, \verb|/|, \verb|^|. Standard functions
 such as \ttt{sin}, \ttt{sqrt}, etc. are available.  See
 Sec.~\ref{sec:real} to Sec.~\ref{sec:complex}.
 
 Numeric values can be associated with units.  Units evaluate to
 numerical factors, and their use is optional, but they can be useful
 in the physics context for which \whizard\ is designed.  Note that the
 default energy/mass unit is \verb|GeV|, and the default unit for cross
 sections is \verb|fbarn|.
 
 
 \subsection{Logical and String}
 
 The language also has the following standard types:
 \begin{itemize}
 \item
    \ttt{logical} (a.k.a.\ boolean). Logical variable names have a
    \ttt{?} (question mark) as prefix.
 \item
    \ttt{string} (arbitrary length).  String variable names have a \ttt{\$}
    (dollar) sign as prefix.
 \end{itemize}
 There are comparisons, logical operations, string concatenation, and a
 mechanism for formatting objects as strings for output.
 
 
 \subsection{Special}
 
 Furthermore, \sindarin\ deals with a bunch of data types tailored
 specifically for Monte Carlo applications:
 \begin{itemize}
 \item
   \ttt{alias} objects denote a set of particle species.
 \item
   \ttt{subevt} objects denote a collection of particle momenta within an
   event.  They have their uses in cut and analysis expressions.
 \item
   \ttt{process} object are generated by a \ttt{process} statement.
   There are no expressions involving processes, but they are referred
   to by \ttt{integrate} and \ttt{simulate} commands.
 \item
   \ttt{model}: There is always a current object of type and name
   \ttt{model}.  Several models can be used concurrently by
   appropriately defining processes, but this happens behind the scenes.
 \item
   \ttt{beams}: Similarly, the current implementation allows only for a single
   object of this type at a given time, which is assigned by a \ttt{beams =}
   statement and used by \ttt{integrate}.
 \end{itemize}
 
 In the current implementation, \sindarin\ has no container data types
 derived from basic types, such as lists, arrays, or hashes, and there
 are no user-defined data types.  (The \ttt{subevt} type is a container
 for particles in the context of events, but there is no type for an
 individual particle: this is represented as a one-particle
 \ttt{subevt}). There are also containers for inclusive processes which
 are however simply handled as an expansion into several components of
 a master process tag.
 
 
 
 
 
 \section{Variables}
 \label{sec:variables}
 
 \sindarin\ supports global variables, variables local to a scoping unit (the
 option body of a command, the body of a \ttt{scan} loop), and variables local
 to an expression.
 
 Some variables are predefined by the system (\emph{intrinsic
   variables}).  They are further separated into \emph{independent}
 variables that can be reset by the user, and \emph{derived} or locked
 variables that are automatically computed by the program, but not
 directly user-modifiable.  On top of that, the user is free to
 introduce his own variables (\emph{user variables}).
 
 The names of numerical variables consist of alphanumeric characters and
 underscores.  The first character must not be a digit.  Logical
 variable names are furthermore prefixed by a
 \ttt{?} (question mark) sign, while string variable names begin
 with a \ttt{\$} (dollar) sign.
 
 Character case does matter.  In this manual we follow the
 convention that variable names consist of lower-case letters,
 digits, and underscores only, but you may also use upper-case
 letters if you wish.
 
 Physics models contain their own, specific set of numeric variables
 (masses, couplings).  They are attached to the model where they are
 defined, so they appear and disappear with the model that is currently
 loaded.  In particular, if two different models contain a variable
 with the same name, these two variables are nevertheless distinct:
 setting one doesn't affect the other.  This feature might be called,
 in computer-science jargon, a \emph{mixin}.
 
 User variables -- global or local -- are declared by their type when they are
 introduced, and acquire an initial value upon declaration.  Examples:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   int i = 3
   real my_cut_value = 10 GeV
   complex c = 3 - 4 * I
   logical ?top_decay_allowed = mH > 2 * mtop
   string $hello = "Hello world!"
   alias q = d:u:s:c
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 An existing user variable can be assigned a new value without a declaration:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   i = i + 1
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 and it may also be redeclared if the new declaration specifies the same type,
 this is equivalent to assigning a new value.
 
 Variables local to an expression are introduced by the \ttt{let ... in}
 contruct.  Example:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   real a = let int n = 2 in
            x^n + y^n
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The explicit \ttt{int} declaration is necessary only if the variable \ttt{n}
 has not been declared before.  An intrinsic variable must not be declared:
 \ttt{let mtop = 175.3 GeV in \ldots}
 
 \ttt{let} constructs can be concatenated if several local variables need to
 be assigned: \ttt{let a = 3 in let b = 4 in \textit{expression}}.
 
 Variables of type \ttt{subevt} can only be defined in \ttt{let} constructs.
 
 Exclusively in the context of particle selections (event analysis), there are
 \emph{observables} as special numeric objects.  They are used like numeric
 variables, but they are never declared or assigned.  They get their value
 assigned dynamically, computed from the particle momentum configuration.
 Hence, they may be understood as (intrinsic and predefined) macros.
 By convention, observable names begin with a capital letter.
 
 Further macros are
 \begin{itemize}
 \item
   \ttt{cuts} and \ttt{analysis}.  They are of type logical, and can be
   assigned an expression by the user.  They are evaluated once for
   each event.
 \item
   \ttt{scale}, \ttt{factorization\_scale} and
   \ttt{renormalization\_scale} are real numeric macros which define the
   energy scale(s) of an event.  The latter two override the former.
   If no scale is defined, the partonic energy is used as the process scale.
 \item
   \ttt{weight} is a real numeric macro.  If it is assigned an
   expression, the expression is evaluated for each valid phase-space
   point, and the result multiplies the matrix element.
 \end{itemize}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{\sindarin\ in Details}
 \label{chap:sindarin}
 
 \section{Data and expressions}
 
 \subsection{Real-valued objects}
 \label{sec:real}
 
 Real literals have their usual form, mantissa and, optionally, exponent:
 \begin{center}
 \ttt{0.}\quad  \ttt{3.14}\quad \ttt{-.5}\quad
 \ttt{2.345e-3}\quad \ttt{.890E-023}
 \end{center}
 Internally, real values are treated as double precision.  The values are read
 by the Fortran library, so details depend on its implementation.
 
 A special feature of \sindarin\ is that numerics (real and integer) can be
 immediately followed by a physical unit.  The supported units are presently
 hard-coded, they are
 \begin{center}
   \ttt{meV}\quad \ttt{eV}\quad \ttt{keV}\quad
   \ttt{MeV}\quad \ttt{GeV}\quad \ttt{TeV}
 \\
   \ttt{nbarn}\quad \ttt{pbarn}\quad \ttt{fbarn}\quad \ttt{abarn}
 \\
   \ttt{rad}\quad \ttt{mrad}\quad \ttt{degree}
 \\
   \ttt{\%}
 \end{center}
 If a number is followed by a unit, it is automatically normalized to the
 corresponding default unit: \ttt{14.TeV} is transformed into the real number
 \ttt{14000.}  Default units are \ttt{GeV}, \ttt{fbarn}, and \ttt{rad}.  The
 \ttt{\%} sign after a number has the effect that the number is multiplied by
 $0.01$.  Note that no checks for consistency of units are done, so you can add
 \ttt{1 meV + 3 abarn} if you absolutely wish to.  Omitting units is always
 allowed, in that case, the default unit is assumed.
 
 Units are not treated as variables.  In particular, you can't write \ttt{theta
   / degree}, the correct form is \ttt{theta / 1 degree}.
 
 There is a single predefined real constant, namely $\pi$ which is referred to
 by the keyword \ttt{pi}. In addition, there is a single predefined
 complex constant, which is the complex unit $i$, being referred to by
 the keyword \ttt{I}.
 
 The arithmetic operators are
 \begin{center}
   \verb|+| \verb|-| \verb|*| \verb|/| \verb|^|
 \end{center}
 with their obvious meaning and the usual precedence rules.
 
 \sindarin\ supports a bunch of standard numerical functions, mostly equivalent
 to their Fortran counterparts:
 \begin{center}
   \ttt{abs}\quad \ttt{conjg}\quad \ttt{sgn}\quad \ttt{mod}\quad \ttt{modulo}
 \\
   \ttt{sqrt}\quad \ttt{exp}\quad \ttt{log}\quad \ttt{log10}
 \\
   \ttt{sin}\quad \ttt{cos}\quad \ttt{tan}\quad
   \ttt{asin}\quad \ttt{acos}\quad \ttt{atan}
 \\
   \ttt{sinh}\quad \ttt{cosh}\quad \ttt{tanh}
 \end{center}
 (Unlike Fortran, the \ttt{sgn} function takes only one argument and returns
 $1.$, or $-1.$) The function argument is enclosed in brackets: \ttt{sqrt
   (2.)}, \ttt{tan (11.5 degree)}.
 
 There are two functions with two real arguments:
 \begin{center}
   \ttt{max}\quad \ttt{min}
 \end{center}
 Example: \verb|real lighter_mass = min (mZ, mH)|
 
 The following functions of a real convert to integer:
 \begin{center}
   \ttt{int}\quad \ttt{nint}\quad \ttt{floor}\quad \ttt{ceiling} %% \; .
 \end{center}
 and this converts to complex type:
 \begin{center}
   \ttt{complex}
 \end{center}
 
 Real values can be compared by the following operators, the result is a
 logical value:
 \begin{center}
   \verb|==|\quad \verb|<>|
 \\
   \verb|>|\quad \verb|<|\quad \verb|>=|\quad \verb|<=|
 \end{center}
 In \sindarin, it is possible to have more than two operands in a logical
 expressions.  The comparisons are done from left to right.  Hence,
 \begin{center}
   \verb|115 GeV < mH < 180 GeV|
 \end{center}
 is valid \sindarin\ code and evaluates to \ttt{true} if the Higgs mass is in the
 given range.
 
 Tests for equality and inequality with machine-precision real numbers are
 notoriously unreliable and should be avoided altogether.  To deal with this
 problem, \sindarin\ has the possibility to make the comparison operators
 ``fuzzy'' which should be read as ``equal (unequal) up to an absolute
 tolerance'', where the tolerance is given by the real-valued intrinsic
 variable \ttt{tolerance}. This variable is initially zero, but can be
 set to any value (for instance, \ttt{tolerance = 1.e-13} by the user.
 Note that for non-zero tolerance, operators like
 \verb|==| and \verb|<>| or \verb|<| and \verb|>| are not mutually
 exclusive\footnote{In older versions of \whizard, until v2.1.1, there
 used to be separate comparators for the comparisons up to a tolerance,
 namely \ttt{==\~{}} and \ttt{<>\~{}}. These have been discarded from
 v2.2.0 on in order to simplify the syntax.}.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Integer-valued objects}
 \label{sec:integer}
 
 Integer literals are obvious:
 \begin{center}
 \ttt{1}\quad \ttt{-98765}\quad \ttt{0123}
 \end{center}
 Integers are always signed.  Their range is the default-integer range as
 determined by the \fortran\ compiler.
 
 Like real values, integer values can be followed by a physical unit: \ttt{1
   TeV}, \ttt{30 degree}.  This actually transforms the integer into a real.
 
 Standard arithmetics is supported:
 \begin{center}
   \verb|+| \verb|-| \verb|*| \verb|/| \verb|^|
 \end{center}
 It is important to note that there is no fraction datatype, and pure integer
 arithmetics does not convert to real.  Hence \ttt{3/4} evaluates to \ttt{0},
 but \ttt{3 GeV / 4 GeV} evaluates to \ttt{0.75}.
 
 Since all arithmetics is handled by the underlying \fortran\ library, integer
 overflow is not detected.  If in doubt, do real arithmetics.
 
 Integer functions are more restricted than real functions.  We support the
 following:
 \begin{center}
   \ttt{abs}\quad \ttt{sgn}\quad \ttt{mod}\quad \ttt{modulo}
 \\
   \ttt{max}\quad \ttt{min}
 \end{center}
 and the conversion functions
 \begin{center}
   \ttt{real}\quad \ttt{complex}
 \end{center}
 Comparisons of integers among themselves and with reals are possible using the
 same set of comparison operators as for real values.  This includes
 the operators with a finite tolerance.
 
 %%%%%%%%%%%%%%%%
 
 \subsection{Complex-valued objects}
 \label{sec:complex}
 
 Complex variables and values are currently not yet used by the physics
 models implemented in \whizard. There complex input coupling constants
 are always split into their real and imaginary parts (or modulus and
 phase). They are exclusively available for arithmetic calculations.
 
 There is no form for complex literals.  Complex values must be created via an
 arithmetic expression,
 \begin{center}
   \ttt{complex c = 1 + 2 * I}
 \end{center}
 where the imaginary unit \ttt{I} is predefined as a constant.
 
 The standard arithmetic operations are supported (also mixed with real and
 integer).  Support for functions is currently still incomplete, among the
 supported functions there are \ttt{sqrt}, \ttt{log}, \ttt{exp}.
 
 
 
 \subsection{Logical-valued objects}
 
 There are two predefined logical constants, \ttt{true} and \ttt{false}.
 Logicals are \emph{not} equivalent to integers (like in C) or to strings (like
 in PERL), but they make up a type of their own.  Only in \verb|printf| output,
 they are treated as strings, that is, they require the \verb|%s| conversion
 specifier.
 
 The names of logical variables begin with a question mark \ttt{?}.  Here is
 the declaration of a logical user variable:
 \begin{quote}
 \begin{footnotesize}
 \begin{footnotesize}
 \begin{verbatim}
 logical ?higgs_decays_into_tt = mH > 2 * mtop
 \end{verbatim}
 \end{footnotesize}
 \end{footnotesize}
 \end{quote}
 
 Logical expressions use the standard boolean operations
 \begin{center}
   \ttt{or}\quad \ttt{and}\quad \ttt{not}
 \end{center}
 The results of comparisons (see above) are logicals.
 
 There is also a special logical operator with lower priority, concatenation by
 a semicolon:
 \begin{center}
   \ttt{\textit{lexpr1} ; \textit{lexpr2}}
 \end{center}
 This evaluates \textit{lexpr1} and throws its result away, then evaluates
 \textit{lexpr2} and returns that result.  This feature is to used with logical
 expressions that have a side effect, namely the \ttt{record} function within
 analysis expressions.
 
 The primary use for intrinsic logicals are flags that change the behavior of
 commands.  For instance, \ttt{?unweighted = true} and \ttt{?unweighted =
   false} switch the unweighting of simulated event samples on and off.
 
 
 \subsection{String-valued objects and string operations}
 \label{sec:sprintf}
 
 String literals are enclosed in double quotes: \ttt{"This is a string."}
 The empty string is \ttt{""}.  String variables begin with the dollar
 sign: \verb|$|. There is only one string operation, concatenation
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 string $foo = "abc" & "def"
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 However, it is possible to transform variables and values to a string using
 the \ttt{sprintf} function.  This function is an interface to the system's \ttt{C}
 function \ttt{sprintf} with some restrictions and modifications.  The allowed
 conversion specifiers are
 \begin{center}
   \verb|%d|\quad \verb|%i| (integer)
 \\
   \verb|%e|\quad \verb|%f|\quad \verb|%g|\quad
   \verb|%E|\quad \verb|%F|\quad \verb|%G| (real)
 \\
   \verb|%s| (string and logical)
 \end{center}
 The conversions can use flag parameter, field width, and precision, but length
 modifiers are not supported since they have no meaning for the application.
 (See also Sec.~\ref{sec:I/O}.)
 
 The \ttt{sprintf} function has the syntax
 \begin{center}
   \ttt{sprintf} \textit{format-string}
   \ttt{(}\textit{arg-list}\ttt{)}
 \end{center}
 This is an expression that evaluates to a string.  The format string contains
 the mentioned conversion specifiers.  The argument list is optional.  The
 arguments are separated by commas.  Allowed arguments are integer, real,
 logical, and string variables, and numeric expressions.  Logical and string
 expressions can also be printed, but they have to be dressed as
 \emph{anonymous variables}.  A logical anonymous variable has the form
 \ttt{?(}\textit{logical\_expr}\ttt{)} (example: \ttt{?(mH > 115 GeV)}).  A
 string anonymous variable has the form \ttt{\$(}\textit{string-expr}\ttt{)}.
 
 Example:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 string $unit = "GeV"
 string $str = sprintf "mW = %f %s" (mW, $unit)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The related \ttt{printf} command with the same syntax prints the formatted
 string to standard output\footnote{In older versions of \whizard,
   until v2.1.1, there also used to be a \ttt{sprintd} function and a
   \ttt{printd} command for default formats without a format
   string. They have been discarded in order to simplify the syntax
   from version v2.2.0 on.}.
 
 
 \section{Particles and (sub)events}
 
 \subsection{Particle aliases}
 \label{sec:alias}
 
 A particle species is denoted by its name as a string: \verb|"W+"|.
 Alternatively, it can be addressed by an \ttt{alias}.  For instance, the $W^+$
 boson has the alias \ttt{Wp}.  Aliases are used like variables in a context
 where a particle species is expected, and the user can specify his/her own
 aliases.
 
 An alias may either denote a single particle species or a class of particles
 species.  A colon \ttt{:} concatenates particle names and aliases to yield
 multi-species aliases:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 alias quark = u:d:s
 alias wboson = "W+":"W-"
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Such aliases are used for defining processes with summation over flavors, and
 for defining classes of particles for analysis.
 
 Each model files define both names and (single-particle) aliases for all
 particles it contains.  Furthermore, it defines the class aliases
 \verb|colored| and \verb|charged| which are particularly useful for event
 analysis.
 
 
 \subsection{Subevents}
 
 Subevents are sets of particles, extracted from an event.  The sets are
 unordered by default, but may be ordered by appropriate functions.  Obviously,
 subevents are meaningful only in a context where an event is available.  The
 possible context may be the specification of a cut, weight, scale, or analysis
 expression.
 
 To construct a simple subevent, we put a particle alias or an expression of
 type particle alias into square brackets:
 \begin{quote}
 \begin{footnotesize}
   \verb|["W+"]|\quad
   \verb|[u:d:s]|\quad
   \verb|[colored]|
 \end{footnotesize}
 \end{quote}
 These subevents evaluate to the set of all $W^+$ bosons (to be precise, their
 four-momenta), all $u$, $d$, or $s$ quarks, and all colored particles,
 respectively.
 
 A subevent can contain pseudoparticles, i.e., particle combinations.
 That is, the four-momenta of
 distinct particles are combined (added conmponent-wise), and the results
 become subevent elements just like ordinary particles.
 
 The (pseudo)particles in a subevent are non-overlapping.  That is, for
 any of the particles in the original event, there is at most one
 (pseudo)particle in the subevent in which it is contained.
 
 Sometimes, variables (actually, named constants) of type subevent are useful.
 Subevent variables are declared by the \ttt{subevt} keyword, and their
 names carry the prefix \verb|@|.  Subevent variables exist only within the
 scope of a \verb|cuts| (or \verb|scale|, \verb|analysis|, etc.) macro, which
 is evaluated in the presence of an actual event.  In the macro body, they are
 assigned via the \ttt{let} construct:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 cuts =
   let subevt @jets = select if Pt > 10 GeV [colored]
   in
   all Theta > 10 degree [@jets, @jets]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 In this expression, we first define \verb|@jets| to stand for the set of all
 colored partons with $p_T>10\;\mathrm{GeV}$.  This abbreviation is then used
 in a logical expression, which evaluates to true if all relative angles
 between distinct jets are greater than $10$ degree.
 
 We note that the example also introduces pairs of subevents: the square
 bracket with two entries evaluates to the list of all possible pairs which do
 not overlap.  The objects within square brackets can be either subevents or
 alias expressions.  The latter are transformed into subevents before they are
 used.
 
 As a special case, the original event is always available as the predefined
 subevent \verb|@evt|.
 
 \subsection{Subevent functions}
 
 There are several functions that take a subevent (or an alias) as an argument
 and return a new subevent.  Here we describe them:
 
 \subsubsection{collect}
 \begin{quote}
 \begin{footnotesize}
   \ttt{collect [\textit{particles}]} \\
   \ttt{collect if \textit{condition} [\textit{particles}]} \\
   \ttt{collect if \textit{condition} [\textit{particles}, \textit{ref\_particles}]}
 \end{footnotesize}
 \end{quote}
 First version: collect all particle momenta in the argument and combine them
 to a single four-momentum.  The \textit{particles} argument may either be a
 \ttt{subevt} expression or an \ttt{alias} expression.  The result is a
 one-entry \ttt{subevt}.  In the second form, only those particles are collected
 which satisfy the \textit{condition}, a logical expression.  Example:
 \ttt{collect if Pt > 10 GeV [colored]}
 
 The third version is useful if you want to put binary observables (i.e.,
 observables constructed from two different particles) in the condition.  The
 \textit{ref\_particles} provide the second argument for binary observables in
 the \textit{condition}.  A particle is taken into account if the condition is
 true with respect to all reference particles that do not overlap with this
 particle.  Example: \ttt{collect if Theta > 5 degree [photon, charged]}:
 combine all photons that are separated by 5 degrees from all charged
 particles.
 
 
 \subsubsection{cluster}
 
 \begin{quote}
 \begin{footnotesize}
   \ttt{cluster [\textit{particles}]} \\
   \ttt{cluster if \textit{condition} [\textit{particles}]} \\
 \end{footnotesize}
 \end{quote}
 First version: collect all particle momenta in the argument and cluster them
 to a set of jets.  The \textit{particles} argument may either be a
 \ttt{subevt} expression or an \ttt{alias} expression.  The result is a
 one-entry \ttt{subevt}.  In the second form, only those particles are clustered
 which satisfy the \textit{condition}, a logical expression.  Example:
 \ttt{cluster if Pt > 10 GeV [colored]}
 
 % The third version is usefule if you want to put binary observables (i.e.,
 % observables constructed from two different particles) in the condition.  The
 % \textit{ref\_particles} provide the second argument for binary observables in
 % the \textit{condition}.  A particle is taken into account if the condition is
 % true with respect to all reference particles that do not overlap with this
 % particle.  Example: \ttt{cluster if Theta > 5 degree [photon, charged]}:
 % combine all photons that are separated by 5 degrees from all charged
 % particles.
 
 This command is available from \whizard\ version 2.2.1 on, and only if
 the \fastjet\ package has been installed and linked with \whizard\
 (cf. Sec.\ref{sec:fastjet}); in a future version of \whizard\ it is
 foreseen to have also an intrinsic clustering package inside \whizard\
 which will be able to support some of the clustering algorithms
 below. To use it in an analysis, you have to set the variable
 \ttt{jet\_algorithm} to one of the predefined jet-algorithm values
 (integer constants):
 \begin{quote}
 \begin{footnotesize}
   \ttt{kt\_algorithm}\\
   \ttt{cambridge\_algorithm}\\
   \ttt{antikt\_algorithm}\\
   \ttt{genkt\_algorithm}\\
   \ttt{cambridge\_for\_passive\_algorithm}\\
   \ttt{genkt\_for\_passive\_algorithm}\\
   \ttt{ee\_kt\_algorithm}\\
   \ttt{ee\_genkt\_algorithm}\\
   \ttt{plugin\_algorithm}
 \end{footnotesize}
 \end{quote}
 and the variable \ttt{jet\_r} to the desired $R$ parameter value, as
 appropriate for the analysis and the jet algorithm.  Example:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   jet_algorithm = antikt_algorithm
   jet_r = 0.7
   cuts = all Pt > 15 GeV [cluster if Pt > 5 GeV [colored]]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 \subsubsection{select\_b\_jet, select\_non\_b\_jet, select\_c\_jet,
   select\_light\_jet}
 
 This command is available from \whizard\ version 2.8.1 on, and it only
 generates anything non-trivial if the \fastjet\ package has been
 installed and linked with \whizard\ (cf. Sec.\ref{sec:fastjet}). It
 only returns sensible results when it is applied to subevents after
 the \ttt{cluster} command (cf. the paragraph before). It is similar to
 the \ttt{select} command, and accepts a logical expression as a
 possible condition. The four commands \ttt{select\_b\_jet},
 \ttt{select\_non\_b\_jet}, \ttt{select\_c\_jet}, and
 \ttt{select\_light\_jet} select $b$ jets, non-$b$ jets 
 (anything lighter than $b$s), $c$ jets (neither $b$ nor light) and
 light jets (anything besides $b$ and $c$), respectively. An example
 looks like this:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   alias lightjet = u:U:d:D:s:S:c:C:gl
   alias jet = b:B:lightjet
   process eebbjj = e1, E1 => b, B, lightjet, lightjet
   jet_algorithm = antikt_algorithm
   jet_r = 0.5
   cuts = let subevt @clustered_jets = cluster [jet] in
          let subevt @bjets = select_b_jet [@clustered_jets] in
          .....
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 \subsubsection{photon\_isolation}
 
 This command is available from \whizard\ version 2.8.1 on. It provides
 isolation of photons from hadronic (and possibly electromagnetic)
 activity in the event to define a (especially) NLO cross section that
 is completely perturbative. The isolation criterion according to
 Frixione, cf.~\cite{Frixione:1998jh}, removes the non-perturbative
 contribution from the photon fragmentation function. This command can
 in principle be applied to elementary hard process partons (and
 leptons), but generates something sensible only if the
 \fastjet\ package has been installed and linked with
 \whizard\ (cf. Sec.\ref{sec:fastjet}). There are three parameters
 which allow to tune the isolation, \ttt{photon\_iso\_r0}, which is the
 radius $R^0_\gamma$ of the isolation cone, \ttt{photon\_iso\_eps},
 which is the fraction $\epsilon_\gamma$ of the photon (transverse)
 energy that enters the isolation criterion, and the exponent of the
 isolation cone, \ttt{photon\_iso\_n}, $n^\gamma$. For more information
 cf.~\cite{Frixione:1998jh}. The command allows also a conditional cut
 on the photon which is applied before the isolation takes place. The
 first argument are the photons in the event, the second the particles
 from which they should be isolated. If also the electromagnetic
 activity is to be isolated, photons need to be isolated from
 themselves and must be included in the second argument. This is
 mandatory if leptons appear in the second argument. Two examples look
 like this:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   alias jet = u:U:d:D:s:S:c:C:gl
   process eeaajj = e1, E1 => A, A, jet, jet
   jet_algorithm = antikt_algorithm
   jet_r = 0.5
   cuts = photon_isolation if Pt > 10 GeV [A, jet]
          ....
   cuts = let subevt @jets = cluster [jet] in         
          photon_isolation if Pt > 10 GeV [A, @jets]
          .....
   process eeajmm = e1, E1 => A, jet, e2, E2
   cuts = let subevt @jets = cluster [jet] in
          let subevt @iso = join [@jets, A:e2:E2]
          photon_isolation [A, @iso]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 
 \subsubsection{combine}
 \begin{quote}
 \begin{footnotesize}
   \ttt{combine [\textit{particles\_1}, \textit{particles\_2}]} \\
   \ttt{combine if \textit{condition}} [\textit{particles\_1}, \textit{particles\_2}]
 \end{footnotesize}
 \end{quote}
 Make a new subevent of composite particles.  The composites are generated by
 combining all particles from subevent \textit{particles\_1} with all particles
 from subevent \textit{particles\_2} in all possible combinations.  Overlapping
 combinations are excluded, however: if a (composite) particle in the first
 argument has a constituent in common with a composite particle in the second
 argument, the combination is dropped.  In particular, this applies if the
 particles are identical.
 
 If a \textit{condition} is provided, the combination is done only when the
 logical expression, applied to the particle pair in question, returns true.
 For instance, here we reconstruct intermediate $W^-$ bosons:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 let @W_candidates = combine if 70 GeV < M < 80 GeV ["mu-", "numubar"]
 in ...
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Note that the combination may fail, so the resulting subevent could be empty.
 
 
 \subsubsection{operator +}
 
 If there is no condition, the $+$ operator provides a convenient
 shorthand for the \verb|combine| command.  In particular, it can be
 used if there are several particles to combine.  Example:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 cuts = any 170 GeV < M < 180 GeV [b + lepton + invisible]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 
 \subsubsection{select}
 \begin{quote}
 \begin{footnotesize}
   \ttt{select if \textit{condition} [\textit{particles}]}   \\
   \ttt{select if \textit{condition} [\textit{particles}, \textit{ref\_particles}]}
 \end{footnotesize}
 \end{quote}
 One argument: select all particles in the argument that satisfy the
 \textit{condition} and drop the rest.  Two arguments: the
 \textit{ref\_particles} provide a second argument for binary observables.
 Select particles if the condition is satisfied for all reference particles.
 
 \subsubsection{extract}
 \begin{quote}
 \begin{footnotesize}
   \ttt{extract [\textit{particles}]}   \\
   \ttt{extract index \textit{index-value} [\textit{particles}]}
 \end{footnotesize}
 \end{quote}
 Return a single-particle subevent.  In the first version, it contains the
 first particle in the subevent \textit{particles}.  In the second version, the
 particle with index \textit{index-value} is returned, where
 \textit{index-value} is an integer expression.  If its value is negative, the
 index is counted from the end of the subevent.
 
 The order of particles in an event or subevent is not always well-defined, so
 you may wish to sort the subevent before applying the \textit{extract}
 function to it.
 
 \subsubsection{sort}
 \begin{quote}
 \begin{footnotesize}
    \ttt{sort [\textit{particles}]} \\
    \ttt{sort by \textit{observable} [\textit{particles}]}   \\
    \ttt{sort by \textit{observable} [\textit{particles}, \textit{ref\_particle}]}
 \end{footnotesize}
 \end{quote}
 Sort the subevent according to some criterion.  If no criterion is supplied
 (first version), the subevent is sorted by increasing PDG code (first
 particles, then antiparticles).  In the second version, the
 \textit{observable} is a real expression which is evaluated for each particle
 of the subevent in turn.  The subevent is sorted by increasing value of this
 expression, for instance:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 let @sorted_evt = sort by Pt [@evt]
 in ...
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 In the third version, a reference particle is provided as second argument, so
 the sorting can be done for binary observables.  It doesn't make much sense to
 have several reference particles at once, so the \ttt{sort} function uses
 only the first entry in the subevent \textit{ref-particle}, if it has more
 than one.
 
 
 \subsubsection{join}
 \begin{quote}
 \begin{footnotesize}
   \ttt{join [\textit{particles}, \textit{new\_particles}]} \\
   \ttt{join if \textit{condition} [\textit{particles}, \textit{new\_particles}]}
 \end{footnotesize}
 \end{quote}
 This commands appends the particles in subevent \textit{new\_particles} to the
 subevent \textit{particles}, i.e., it joins the two particle sets.  To be
 precise, a (pseudo)particle from \textit{new\_particles} is only appended if it
 does not overlap with any of the (pseudo)particles
 present in \textit{particles}, so the function will not produce overlapping
 entries.
 
 In the second version, each particle from \textit{new\_particles} is also
 checked with all particles in the first set whether \textit{condition} is
 fulfilled.  If yes, and there is no overlap, it is appended, otherwise
 it is dropped.
 
 
 \subsubsection{operator \&}
 
 Subevents can also be concatenated by the operator \verb|&|.  This effectively
 applies \ttt{join} to all operands in turn.  Example:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 let @visible =
     select if Pt > 10 GeV and E > 5 GeV [photon]
   & select if Pt > 20 GeV and E > 10 GeV [colored]
   & select if Pt > 10 GeV [lepton]
 in ...
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 
 \subsection{Calculating observables}
 
 Observables (invariant mass \ttt{M}, energy \ttt{E}, \ldots) are used in
 expressions just like ordinary numeric variables.  By convention, their names
 start with a capital letter.  They are computed using a particle momentum (or
 two particle momenta) which are taken from a subsequent subevent argument.
 
 We can extract the value of an observable for an event and make it available
 for computing the \ttt{scale} value, or for histogramming etc.:
 
 \subsubsection{eval}
 \begin{quote}
 \begin{footnotesize}
   \ttt{eval \textit{expr} [\textit{particles}]} \\
   \ttt{eval \textit{expr} [\textit{particles\_1}, \textit{particles\_2}]}
 \end{footnotesize}
 \end{quote}
 
 The function \ttt{eval} takes an expression involving observables and
 evaluates it for the first momentum (or momentum pair) of the subevent (or
 subevent pair) in square brackets that follows the expression.  For example,
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   eval Pt [colored]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 evaluates to the transverse momentum of the first colored particle,
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   eval M [@jets, @jets]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 evaluates to the invariant mass of the first distinct pair of jets (assuming
 that \verb|@jets| has been defined in a \ttt{let} construct), and
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   eval E - M [combine [e1, N1]]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 evaluates to the difference of energy and mass of the combination of the first
 electron-neutrino pair in the event.
 
 The last example illustrates why observables are treated like variables, even
 though they are functions of particles: the \ttt{eval} construct with the
 particle reference in square brackets after the expression allows to compute
 derived observables -- observables which are functions of new observables --
 without the need for hard-coding them as new functions.
 
 
 \subsection{Cuts and event selection}
 \label{sec:cuts}
 
 Instead of a numeric value, we can use observables to compute a logical value.
 
 \subsubsection{all}
 \begin{quote}
 \begin{footnotesize}
   \ttt{all \textit{logical\_expr} [\textit{particles}]} \\
   \ttt{all \textit{logical\_expr} [\textit{particles\_1}, \textit{particles\_2}]}
 \end{footnotesize}
 \end{quote}
 The \ttt{all} construct expects a logical expression and one or two subevent
 arguments in square brackets.
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   all Pt > 10 GeV [charged]
   all 80 GeV < M < 100 GeV [lepton, antilepton]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 In the second example, \ttt{lepton} and \ttt{antilepton} should be aliases
 defined in a \ttt{let} construct.  (Recall that aliases are promoted to
 subevents if they occur within square brackets.)
 
 This construction defines a cut.  The result value is \ttt{true} if the
 logical expression evaluates to \ttt{true} for all particles in the subevent
 in square brackets.  In the two-argument case it must be \ttt{true} for all
 non-overlapping combinations of particles in the two subevents.  If one of the
 arguments is the empty subevent, the result is also \ttt{true}.
 
 \subsubsection{any}
 \begin{quote}
 \begin{footnotesize}
   \ttt{any \textit{logical\_expr} [\textit{particles}]} \\
   \ttt{any \textit{logical\_expr} [\textit{particles\_1}, \textit{particles\_2}]}
 \end{footnotesize}
 \end{quote}
 The \ttt{any} construct is true if the logical expression is true for at least
 one particle or non-overlapping particle combination:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   any E > 100 GeV [photon]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This defines a trigger or selection condition.  If a subevent argument is
 empty, it evaluates to \ttt{false}
 
 \subsubsection{no}
 \begin{quote}
 \begin{footnotesize}
   \ttt{no \textit{logical\_expr} [\textit{particles}]} \\
   \ttt{no \textit{logical\_expr} [\textit{particles\_1}, \textit{particles\_2}]}
 \end{footnotesize}
 \end{quote}
 The \ttt{no} construct is true if the logical expression is true for no single
 one particle or non-overlapping particle combination:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   no 5 degree < Theta < 175 degree ["e-":"e+"]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This defines a veto condition.  If a subevent argument is empty, it
 evaluates to \ttt{true}.  It is equivalent to \ttt{not any\ldots}, but
 included for notational convenience.
 
 
 \subsection{More particle functions}
 
 \subsubsection{count}
 \begin{quote}
 \begin{footnotesize}
   \ttt{count [\textit{particles}]} \\
   \ttt{count [\textit{particles\_1}, \textit{particles\_2}]} \\
   \ttt{count if \textit{logical-expr} [\textit{particles}]} \\
   \ttt{count if \textit{logical-expr} [\textit{particles}, \textit{ref\_particles}]}
 \end{footnotesize}
 \end{quote}
 This counts the number of events in a subevent, the result is of type
 \ttt{int}.  If there is a conditional expression, it counts the number of
 \ttt{particle} in the subevent that pass the test.   If there are two
 arguments, it counts the number of non-overlapping particle pairs (that pass
 the test, if any).
 
 
 \subsubsection{Predefined observables}
 
 The following real-valued observables are available in \sindarin\ for use in
 \ttt{eval}, \ttt{all}, \ttt{any}, \ttt{no}, and \ttt{count} constructs.  The
 argument is always the subevent or alias enclosed in square brackets.
 \begin{itemize}
 \item \ttt{M2}
   \begin{itemize}
   \item One argument: Invariant mass squared of the (composite) particle in the
     argument.
   \item Two arguments: Invariant mass squared of the sum of the two momenta.
   \end{itemize}
 \item \ttt{M}
   \begin{itemize}
   \item Signed square root of \ttt{M2}: positive if $\ttt{M2}>0$, negative if
     $\ttt{M2}<0$.
   \end{itemize}
 \item \ttt{E}
   \begin{itemize}
   \item One argument: Energy of the (composite) particle in the argument.
   \item Two arguments: Sum of the energies of the two momenta.
   \end{itemize}
 \item \ttt{Px}, \ttt{Py}, \ttt{Pz}
   \begin{itemize}
   \item Like \ttt{E}, but returning the spatial momentum components.
   \end{itemize}
 \item \ttt{P}
   \begin{itemize}
   \item Like \ttt{E}, returning the absolute value of the spatial momentum.
   \end{itemize}
 \item \ttt{Pt}, \ttt{Pl}
   \begin{itemize}
   \item Like \ttt{E}, returning the transversal and longitudinal momentum,
     respectively.
   \end{itemize}
 \item \ttt{Theta}
   \begin{itemize}
   \item One argument: Absolute polar angle in the lab frame
   \item Two arguments: Angular distance of two particles in the lab frame.
   \end{itemize}
 \item \ttt{Theta\_star}
   Only with two arguments, gives the relative polar angle of the two momenta
   in the rest system of the momentum sum (i.e. mother particle).
 \item \ttt{Phi}
   \begin{itemize}
   \item One argument: Absolute azimuthal angle in the lab frame
   \item Two arguments: Azimuthal distance of two particles in the lab frame
   \end{itemize}
 \item \ttt{Rap}, \ttt{Eta}
   \begin{itemize}
   \item One argument: rapidity / pseudorapidity
   \item Two arguments: rapidity / pseudorapidity difference
   \end{itemize}
 \item \ttt{Dist}
   \begin{itemize}
   \item Two arguments: Distance on the $\eta$-$\phi$ cylinder, i.e.,
     $\sqrt{\Delta\eta^2 + \Delta\phi^2}$
   \end{itemize}
 \item \ttt{kT}
   \begin{itemize}
   \item Two arguments: $k_T$ jet clustering variable:
     $2 \min (E_{j1}^2, E_{j2}^2) / Q^2 \times (1 -
     \cos\theta_{j1,j2})$. At the moment, $Q^2 = 1$ GeV$^2$.
   \end{itemize}
 \end{itemize}
 There are also integer-valued observables:
 \begin{itemize}
 \item \ttt{PDG}
   \begin{itemize}
   \item One argument: PDG code of the particle.  For a composite particle, the
     code is undefined (value 0).  For flavor sums in the \ttt{cuts} statement,
     this observable always returns the same flavor, i.e. the first one from the
     flavor list.  It is thus only sensible to use it in an \ttt{analysis} or
     \ttt{selection} statement when simulating events.
   \end{itemize}
 \item \ttt{Ncol}
   \begin{itemize}
   \item One argument: Number of open color lines.  Only count color
     lines, not anticolor lines.  This is defined only if the global flag
     \ttt{?colorize\_subevt} is true.
   \end{itemize}
 \item \ttt{Nacl}
   \begin{itemize}
   \item One argument: Number of open anticolor lines.  Only count anticolor
     lines, not color lines.  This is defined only if the global flag
     \ttt{?colorize\_subevt} is true.
   \end{itemize}
 \end{itemize}
 
 
 %%%%%%%%%%%%%%%
 
 \section{Physics Models}
 \label{sec:models}
 
 A physics model is a combination of particles, numerical parameters (masses,
 couplings, widths), and Feynman rules.  Many physics analyses are done in the
 context of the Standard Model (SM).  The SM is also the default model for
 \whizard.  Alternatively, you can choose a subset of the SM (QED or QCD),
 variants of the SM (e.g., with or without nontrivial CKM matrix), or various
 extensions of the SM.  The complete list is displayed in
 Table~\ref{tab:models}.
 
 The model definitions are contained in text files with filename extension
 \ttt{.mdl}, e.g., \ttt{SM.mdl}, which are located in the \ttt{share/models}
 subdirectory of the \whizard\ installation.  These files are easily readable,
 so if you need details of a model implementation, inspect their contents.  The
 model file contains the complete particle and parameter definitions as well as
 their default values.  It also contains a list of vertices.  This is used only
 for phase-space setup; the vertices used for generating amplitudes and the
 corresponding Feynman rules are stored in different files within the
 \oMega\ source tree.
 
 In a \sindarin\ script, a model is a special object of type \ttt{model}.  There
 is always a \emph{current} model.  Initially, this is the SM, so on startup
 \whizard\ reads the \ttt{SM.mdl} model file and assigns its content to the
 current model object.  (You can change the default model by the \ttt{--model}
 option on the command line. Also the preloading of a model can be
 switched off with the \ttt{--no-model} option)  Once the model has
 been loaded, you can define processes for the model, and you have all
 independent model parameters at your disposal.  As noted before, these
 are intrinsic parameters which need not be declared when you assign
 them a value, for instance:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   mW = 80.33 GeV
   wH = 243.1 MeV
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Other parameters are \emph{derived}.  They can be used in expressions like any
 other parameter, they are also intrinsic, but they cannot be modified directly
 at all.  For instance, the electromagnetic coupling \ttt{ee} is a derived
 parameter.  If you change either \ttt{GF} (the Fermi constant), \ttt{mW} (the
 $W$ mass), or \ttt{mZ} (the $Z$ mass), this parameter will reflect the change,
 but setting it directly is an error.  In other words, the SM is defined within
 \whizard\ in the $G_F$-$m_W$-$m_Z$ scheme.  (While this scheme is unusual for
 loop calculations, it is natural for a tree-level event generator where the
 $Z$ and $W$ poles have to be at their experimentally determined
 location\footnote{In future versions of \whizard\ it is foreseen to
   implement other electroweak schemes.}.)
 
 The model also defines the particle names and aliases that you can use for
 defining processes, cuts, or analyses.
 
 If you would like to generate a SUSY process instead, for instance, you can
 assign a different model (cf.\ Table~\ref{tab:models}) to the current model
 object:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   model = MSSM
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This assignment has the consequence that the list of SM parameters and
 particles is replaced by the corresponding MSSM list (which is much longer).
 The MSSM contains essentially all SM parameters by the same name, but in fact
 they are different parameters.  This is revealed when you say
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   model = SM
   mb = 5.0 GeV
   model = MSSM
   show (mb)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 After the model is reassigned, you will see the MSSM value of $m_b$ which
 still has its default value, not the one you have given.  However, if you
 revert to the SM later,
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   model = SM
   show (mb)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 you will see that your modification of the SM's $m_b$ value has been
 remembered.  If you want both mass values to agree, you have to set them
 separately in the context of their respective model.  Although this might seem
 cumbersome at first, it is nevertheless a sensible procedure since the
 parameters defined by the user might anyhow not be defined or available for
 all chosen models.
 
 When using two different models which need an SLHA input file,
 these {\em have} to be provided for both models.
 
 Within a given scope, there is only one current model.  The current model can
 be reset permanently as above.  It can also be temporarily be reset in a local
 scope, i.e., the option body of a command or the body of a \ttt{scan} loop.
 It is thus possible to use several models within the same script.  For
 instance, you may define a SUSY signal process and a pure-SM background
 process. Each process depends only on the respective model's parameter set,
 and a change to a parameter in one of the models affects only the
 corresponding process.
 
 
 \section{Processes}
 \label{sec:processes}
 
 The purpose of \whizard\ is the integration and simulation of high-energy
 physics processes: scatterings and decays.  Hence, \ttt{process} objects play
 the central role in \sindarin\ scripts.
 
 A \sindarin\ script may contain an arbitrary number of process definitions.  The
 initial states need not agree, and the processes may belong to different
 physics models.
 
 
 \subsection{Process definition}
 \label{sec:procdef}
 
 A process object is defined in a straightforward notation.  The definition
 syntax is straightforward:
 \begin{quote}
 \begin{footnotesize}
   \ttt{process \textit{process-id} = \textit{incoming-particles}} \verb|=>|
   \ttt{\textit{outgoing-particles}}
 \end{footnotesize}
 \end{quote}
 Here are typical examples:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   process w_pair_production = e1, E1 => "W+", "W-"
   process zdecay = Z => u, ubar
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Throughout the program, the process will be identified by its
 \textit{process-id}, so this is the name of the process object.  This
 identifier is arbitrary, chosen by the user.  It follows the rules for
 variable names, so it consists of alphanumeric characters and underscores,
 where the first character is not numeric.  As a special rule, it must not
 contain upper-case characters.  The reason is that this name is used for
 identifying the process not just within the script, but also within the
 \fortran\ code that the matrix-element generator produces for this process.
 
 After the equals sign, there follow the lists of incoming and outgoing
 particles.  The number of incoming particles is either one or two: scattering
 processes and decay processes.  The number of outgoing particles should be two
 or larger (as $2\to 1$ processes are proportional to a $\delta$
 function they can only be sensibly integrated when using a structure
 function like a hadron collider PDF or a beamstrahlung spectrum.).
 There is no hard upper limit; the complexity of processes that
 \whizard\ can handle depends only on the practical computing
 limitations (CPU time and memory).  Roughly speaking, one can assume
 that processes up to $2\to 6$ particles are safe, $2\to 8$ processes
 are feasible given sufficient time for reaching a stable integration,
 while more complicated processes are largely unexplored.
 
 We emphasize that in the default setup, the matrix element of a physics
 process is computed exactly in leading-order perturbation theory, i.e., at
 tree level.  There is no restriction of intermediate states, the result always
 contains the complete set of Feynman graphs that connect the initial with the
 final state.  If the result would actually be expanded in Feynman graphs
 (which is not done by the \oMega\ matrix element generator that
 \whizard\ uses), the number of graphs can easily reach several thousands,
 depending on the complexity of the process and on the physics model.
 
 More details about the different methods for quantum field-theoretical
 matrix elements can be found in Chap.~\ref{chap:hardint}. In the
 following, we will discuss particle names, options for processes like
 restrictions on intermediate states, parallelization, flavor sums and
 process components for inclusive event samples (process containers).
 
 
 \subsection{Particle names}
 
 The particle names are taken from the particle definition in the current model
 file.  Looking at the SM, for instance, the electron entry in
 \ttt{share/models/SM.mdl} reads
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 particle E_LEPTON 11
   spin 1/2  charge  -1   isospin -1/2
   name "e-" e1 electron e
   anti "e+" E1 positron
   tex_name "e^-"
   tex_anti "e^+"
   mass me
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This tells that you can identify an electron either as \verb|"e-"|, \verb|e1|,
 \verb|electron|, or simply \verb|e|.  The first version is used for output,
 but needs to be quoted, because otherwise \sindarin\ would interpret the minus
 sign as an operator.  (Technically, unquoted particle identifiers are aliases,
 while the quoted versions -- you can say either \verb|e1| or \verb|"e1"| --
 are names.  On input, this makes no difference.)  The alternative version
 \verb|e1| follows a convention, inherited from
 \comphep~\cite{Boos:2004kh}, that particles are indicated by lower
 case, antiparticles by upper case, and for leptons, the generation
 index is appended: \verb|e2| is the muon, \verb|e3| the tau.  These
 alternative names need not be quoted because they contain no special
 characters.
 
 In Table~\ref{tab:SM-particles}, we list the recommended names as well as
 mass and width parameters for all SM particles.  For other models, you may
 look up the names in the corresponding model file.
 
 \begin{table}[p]
   \begin{center}
     \begin{tabular}{|l|l|l|l|cc|}
       \hline
       & Particle & Output name & Alternative names & Mass & Width\\
       \hline\hline
       Leptons
       &$e^-$ & \verb|e-| & \ttt{e1}\quad\ttt{electron} & \ttt{me} & \\
       &$e^+$ & \verb|e+| & \ttt{E1}\quad\ttt{positron} & \ttt{me} & \\
       \hline
       &$\mu^-$ & \verb|mu-| & \ttt{e2}\quad\ttt{muon} & \ttt{mmu} & \\
       &$\mu^+$ & \verb|mu+| & \ttt{E2} & \ttt{mmu} & \\
       \hline
       &$\tau^-$ & \verb|tau-| & \ttt{e3}\quad\ttt{tauon} & \ttt{mtau} & \\
       &$\tau^+$ & \verb|tau+| & \ttt{E3} & \ttt{mtau} & \\
       \hline\hline
       Neutrinos
       &$\nu_e$ & \verb|nue| & \ttt{n1} & & \\
       &$\bar\nu_e$ & \verb|nuebar| & \ttt{N1} & & \\
       \hline
       &$\nu_\mu$ & \verb|numu| & \ttt{n2} & & \\
       &$\bar\nu_\mu$ & \verb|numubar| & \ttt{N2} & & \\
       \hline
       &$\nu_\tau$ & \verb|nutau| & \ttt{n3} & & \\
       &$\bar\nu_\tau$ & \verb|nutaubar| & \ttt{N3} & & \\
       \hline\hline
       Quarks
       &$d$ & \verb|d| & \ttt{down} & & \\
       &$\bar d$ & \verb|dbar| & \ttt{D} & & \\
       \hline
       &$u$ & \verb|u| & \ttt{up} & & \\
       &$\bar u$ & \verb|ubar| & \ttt{U} & & \\
       \hline
       &$s$ & \verb|s| & \ttt{strange} & \ttt{ms} & \\
       &$\bar s$ & \verb|sbar| & \ttt{S} & \ttt{ms}  & \\
       \hline
       &$c$ & \verb|c| & \ttt{charm} & \ttt{mc}  & \\
       &$\bar c$ & \verb|cbar| & \ttt{C} & \ttt{mc} & \\
       \hline
       &$b$ & \verb|b| & \ttt{bottom} & \ttt{mb} & \\
       &$\bar b$ & \verb|bbar| & \ttt{B} &  \ttt{mb} & \\
       \hline
       &$t$ & \verb|t| & \ttt{top} &  \ttt{mtop} & \ttt{wtop} \\
       &$\bar t$ & \verb|tbar| & \ttt{T} &  \ttt{mtop} & \ttt{wtop} \\
       \hline\hline
       Vector bosons
       &$g$ & \verb|gl| & \ttt{g}\quad\ttt{G}\quad\ttt{gluon} & & \\
       \hline
       &$\gamma$ & \verb|A| & \ttt{gamma}\quad\ttt{photon} & & \\
       \hline
       &$Z$ & \verb|Z| & & \ttt{mZ} & \ttt{wZ} \\
       \hline
       &$W^+$ & \verb|W+| & \ttt{Wp} & \ttt{mW} & \ttt{wW} \\
       &$W^-$ & \verb|W-| & \ttt{Wm} & \ttt{mW} & \ttt{wW} \\
       \hline\hline
       Scalar bosons
       &$H$ & \verb|H| & \ttt{h}\quad \ttt{Higgs} & \ttt{mH} & \ttt{wH} \\
       \hline
     \end{tabular}
   \end{center}
   \caption{\label{tab:SM-particles} Names that can be used for SM particles.
     Also shown are the intrinsic variables that can be used to set mass and
     width, if applicable.}
 \end{table}
 
 Where no mass or width parameters are listed in the table, the particle is
 assumed to be massless or stable, respectively.  This is obvious for particles
 such as the photon.  For neutrinos, the mass is meaningless to particle
 physics collider experiments, so it is zero.  For quarks, the $u$ or
 $d$ quark mass is unobservable directly, so we also set it zero.  For
 the heavier quarks, the mass may play a role, so it is kept.  (The $s$
 quark is borderline; one may argue that its mass is also unobservable
 directly.)  On the other hand, the electron mass is relevant, e.g., in
 photon radiation without cuts, so it is not zero by default.
 
 It pays off to set particle masses to zero, if the approximation is justified,
 since fewer helicity states will contribute to the matrix element.  Switching
 off one of the helicity states of an external fermion speeds up the
 calculation by a factor of two.  Therefore, script files will usually contain
 the assignments
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   me = 0  mmu = 0  ms = 0  mc = 0
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 unless they deal with processes where this simplification is
 phenomenologically unacceptable.  Often $m_\tau$ and $m_b$ can also be
 neglected, but this excludes processes where the Higgs couplings of $\tau$ or
 $b$ are relevant.
 
 Setting fermion masses to zero enables, furthermore, the possibility to define
 multi-flavor aliases
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   alias q = d:u:s:c
   alias Q = D:U:S:C
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 and handle processes such as
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   process two_jets_at_ilc = e1, E1 => q, Q
   process w_pairs_at_lhc = q, Q => Wp, Wm
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 where a sum over all allowed flavor combination is automatically included.
 For technical reasons, such flavor sums are possible only for massless
 particles (or more general for mass-degenerate particles). If you want
 to generate inclusive processes with sums over particles of different
 masses (e.g. summing over $W/Z$ in the final state etc.), confer below
 the section about process components, Sec.~\ref{sec:processcomp}.
 
 Assignments of masses, widths and other parameters are actually in effect when
 a process is integrated, not when it is defined.  So, these assignments may
 come before or after the process definition, with no significant difference.
 However, since flavor summation requires masses to be zero, the assignments
 may be put before the alias definition which is used in the process.
 
 The muon, tau, and the heavier quarks are actually unstable.  However, the
 width is set to zero because their decay is a macroscopic effect and, except for
 the muon, affected by hadron physics, so it is not described by \whizard.  (In
 the current \whizard\ setup, all decays occur at the production vertex.  A
 future version may describe hadronic physics and/or macroscopic particle
 propagation, and this restriction may be eventually removed.)
 
 
 
 
 \subsection{Options for processes}
 \label{sec:process options}
 
 The \ttt{process} definition may contain an optional argument:
 \begin{quote}
 \begin{footnotesize}
   \ttt{process \textit{process-id} = \textit{incoming-particles}} \verb|=>|
   \ttt{\textit{outgoing-particles}} \ttt{\{\textit{options\ldots}\}}
 \end{footnotesize}
 \end{quote}
 The \textit{options} are a \sindarin\ script that is executed in a context local
 to the \ttt{process} command.  The assignments it contains apply only to the
 process that is defined. In the following, we describe the set of potentially
 useful options (which all can be also set globally):
 
 \subsubsection{Model reassignment}
 
 It is possible to locally reassign the model via a  \ttt{model =} statment,
 permitting the definition of process using a model other than the globally
 selected model. The process will retain this association during
 integration and event generation.
 
 \subsubsection{Restrictions on matrix elements}
 \label{subsec:restrictions}
 
 Another useful option is the setting
 \begin{quote}
 \begin{footnotesize}
   \verb|$restrictions =| \ttt{\textit{string}}
 \end{footnotesize}
 \end{quote}
 This option allows to select particular classes of Feynman graphs for the
 process when using the \oMega\ matrix element generator.  The
 \verb|$restrictions| string specifies e.g. propagators that the graph
 must contain.  Here is an example:
 \begin{code}
   process zh_invis = e1, E1 => n1:n2:n3, N1:N2:N3, H { $restrictions = "1+2 ~ Z" }
 \end{code}
 The complete process $e^-e^+ \to \nu\bar\nu H$, summed over all neutrino
 generations,  contains both $ZH$ pair production (Higgs-strahlung) and
 $W^+W^-\to H$ fusion.  The restrictions string selects the Higgs-strahlung
 graph where the initial electrons combine to a $Z$ boson.  Here, the particles
 in the process are consecutively numbered, starting with the initial
 particles.  An alternative for the same selection would be
 \verb|$restrictions = "3+4 ~ Z"|.  Restrictions can be combined using
 \verb|&&|, for instance
 \begin{code}
   $restrictions = "1+2 ~ Z && 3 + 4 ~ Z"
 \end{code}
 which is redundant here, however.
 
 The restriction keeps the full energy dependence in the intermediate
 propagator, so the Breit-Wigner shape can be observed in distributions.  This
 breaks gauge invariance, in particular if the intermediate state is off shell,
 so you should use the feature only if you know the implications. For
 more details, cf. the Chap.~\ref{chap:hardint} and the \oMega\ manual.
 
 Other restrictions that can be combined with the restrictions above on
 intermediate propagators allow to exclude certain particles from
 intermediate propagators, or to exclude certain vertices from the
 matrix elements. For example,
 \begin{code}
   process eemm = e1, E1 => e2, E2  { $restrictions = "!A" }
 \end{code}
 would exclude all photon propagators from the matrix element and
 leaves only the $Z$ exchange here. In the same way,
 \verb|$restrictions = "!gl"| would exclude all gluon exchange. This
 exclusion of internal propagators works also for lists of particles,
 like
 \begin{code}
   $restrictions = "!Z:H"
 \end{code}
 excludes all $Z$ and $H$ propagators from the matrix elements.
 
 Besides excluding certain particles as internal lines, it is also
 possible to exclude certain vertices using the restriction command
 \begin{code}
   process eeww = e1, E1 => Wp, Wm  { $restrictions = "^[W+,W-,Z]" }
 \end{code}
 This would generate the matrix element for the production of two $W$
 bosons at LEP without the non-Abelian vertex $W^+W^-Z$. Again, these
 restrictions are able to work on lists, so
 \begin{code}
   $restrictions = "^[W+,W-,A:Z]"
 \end{code}
 would exclude all triple gauge boson vertices from the above process
 and leave only the $t$-channel neutrino exchange.
 
 It is also possible to exlude vertices by their coupling constants,
 e.g. the photon exchange in the process $e^+ e^- \to \mu^+ \mu^-$ can
 also be removed by the following restriction:
 \begin{code}
   $restrictions = "^qlep"
 \end{code}
 Here, \ttt{qlep} is the \fortran\ variable for the coupling constant
 of the electron-positron-photon vertex.
 
 \begin{table}
   \begin{center}
     \begin{tabular}{|l|l|}
       \hline
       \verb|3+4~Z| & external particles 3 and 4 must come from
       intermediate $Z$ \\\hline
       \verb| && |   & logical ``and'', e.g. in
       \verb| 3+5~t && 4+6~tbar| \\\hline
       \verb| !A | & exclude all $\gamma$ propagators \\\hline
       \verb| !e+:nue | & exclude a list of propagators, here $\gamma$,
       $\nu_e$ \\\hline
       \verb|^qlep:gnclep| & exclude all vertices with
       \ttt{qlep},\ttt{gnclep} coupling constants \\\hline
       \verb|^[A:Z,W+,W-]| & exclude all vertices $W^+W^-Z$,
       $W^+W^-\gamma$ \\\hline
       \verb|^c1:c2:c3[H,H,H]| & exclude all triple Higgs couplings
       with $c_i$ constants
       \\\hline
     \end{tabular}
   \end{center}
   \caption{List of possible restrictions that can be applied to
     \oMega\ matrix elements.}
   \label{tab:restrictions}
 \end{table}
 The Tab.~\ref{tab:restrictions} gives a list of options that can be
 applied to the \oMega\ matrix elements.
 
 
 \subsubsection{Other options}
 
 There are some further options that the \oMega\ matrix-element generator can
 take.  If desired, any string of options that is contained in this variable
 \begin{quote}
 \begin{footnotesize}
   \verb|$omega_flags =| \ttt{\textit{string}}
 \end{footnotesize}
 \end{quote}
 will be copied verbatim to the \oMega\ call, after all other options.
 
 One important application is the scheme of treating the width of unstable
 particles in the $t$-channel.  This is modified by the \verb|model:| class of
 \oMega\ options.
 
 It is well known that for some processes, e.g., single $W$ production from
 photon-$W$ fusion, gauge invariance puts constraints on the treatment of the
 unstable-particle width.  By default, \oMega\ puts a nonzero width in the $s$
 channel only.  This correctly represents the resummed Dyson series for the
 propagator, but it violates QED gauge invariance, although the effect is only
 visible if the cuts permit the photon to be almost on-shell.
 
 An alternative is
 \begin{quote}
 \begin{footnotesize}
   \verb|$omega_flags = "-model:fudged_width"|
 \end{footnotesize}
 \end{quote}
 which puts zero width in the matrix element, so that gauge cancellations
 hold, and reinstates the $s$-channel width in the appropriate places by an
 overall factor that multiplies the whole matrix element.
 
 Another possibility is
 \begin{quote}
 \begin{footnotesize}
   \verb|$omega_flags = "-model:constant_width"|
 \end{footnotesize}
 \end{quote}
 which puts the width both in the $s$ and in the $t$ channel everywhere.
 
 Note that both options apply only to charged unstable particles, such as the
 $W$ boson.
 
 
 \subsubsection{Multithreaded calculation of helicity sums via OpenMP}
 \label{sec:openmp}
 
 On multicore and / or multiprocessor systems, it is possible to speed
 up the calculation by using multiple threads to perform the helicity
 sum in the matrix element calculation. As the processing time used by
 \whizard\ is not used up solely in the matrix element, the speedup thus
 achieved varies greatly depending on the process under consideration;
 while simple processes without flavor sums do not profit significantly
 from this parallelization, the computation time for processes
 involving flavor sums with four or more particles in the final state
 is typically reduced by a factor between two and three when utilizing
 four parallel threads.
 
 The parallization is implemented using \ttt{OpenMP} and requires
 \whizard\ to be compiled with an \ttt{OpenMP} aware compiler and the
 appropiate compiler flags This is done in the configuration step, cf.\
 Sec.~\ref{sec:installation}.
 
 As with all \ttt{OpenMP} programs, the default number of threads used at
 runtime is up to the compiler runtime support and typically set to the
 number of independent hardware threads (cores / processors /
 hyperthreads) available in the system.  This default can be adjusted
 by setting the \ttt{OMP\_NUM\_THREADS} environment variable prior to
 calling WHIZARD.  Alternatively, the available number of threads can
 be reset anytime by the \sindarin\ parameter
 \ttt{openmp\_num\_threads}.  Note however that the total number of
 threads that can be sensibly used is limited by the number of
 nonvanishing helicity combinations.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Process components}
 \label{sec:processcomp}
 
 It was mentioned above that processes with flavor sums (in the initial
 or final state or both) have to be mass-degenerate (in most cases
 massless) in all particles that are summed over at a certain
 position. This condition is necessary in order to use the same
 phase-space parameterization and integration for the flavor-summed
 process. However, in many applications the user wants to handle
 inclusive process definitions, e.g. by defining inclusive decays,
 inclusive SUSY samples at hadron colliders (gluino pairs, squark
 pairs, gluino-squark associated production), or maybe lepton-inclusive
 samples where the tau and muon mass should be kept at different
 values. In \whizard\, from version v2.2.0 on, there is the possibility
 to define such inclusive process containers. The infrastructure for
 this feature is realized via so-called process components: processes
 are allowed to contain several process components. Those components
 need not be provided by the same matrix element generator,
 e.g. internal matrix elements, \oMega\ matrix elements, external
 matrix element (e.g. from a one-loop program, OLP) can be mixed. The
 very same infrastructure can also be used for next-to-leading order
 (NLO) calculations, containing the born with real emission, possible
 subtraction terms to make the several components infrared- and
 collinear finite, as well as the virtual corrections.
 
 Here, we want to discuss the use for inclusive particle samples. There
 are several options, the simplest of which to add up different final
 states by just using the \ttt{+} operator in \sindarin, e.g.:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
    process multi_comp = e1, E1 => (e2, E2) + (e3, E3) + (A, A)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The brackets are not only used for a better grouping of the expressions,
 they are not mandatory for \whizard\ to interpret the sum
 correctly. When integrating, \whizard\ tells you that this a process
 with three different components:
 \begin{footnotesize}
 \begin{Verbatim}
 | Initializing integration for process multi_comp_1_p1:
 | ------------------------------------------------------------------------
 | Process [scattering]: 'multi_comp'
 |   Library name  = 'default_lib'
 |   Process index = 1
 |   Process components:
 |     1: 'multi_comp_i1':   e-, e+ => m-, m+ [omega]
 |     2: 'multi_comp_i2':   e-, e+ => t-, t+ [omega]
 |     3: 'multi_comp_i3':   e-, e+ => A, A [omega]
 | ------------------------------------------------------------------------
 \end{Verbatim}
 \end{footnotesize}
 A different phase-space setup is used for each different
 component. The integration for each different component is performed
 separately, and displayed on screen. At the end, a sum of all
 components is shown. All files that depend on the components are being
 attached an \ttt{\_i{\em <n>}} where \ttt{{\em <n>}} is the number of
 the process component that appears in the list above: the \fortran\
 code for the matrix element, the \ttt{.phs} file for the phase space
 parameterization, and the grid files for the \vamp\ Monte-Carlo
 integration (or any other integration method). However, there will be
 only one event file for the inclusive process, into which a mixture of
 events according to the size of the individual process component cross
 section enter.
 
 More options are to specify additive lists of particles. \whizard\
 then expands the final states according to tensor product algebra:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
    process multi_tensor = e1, E1 => e2 + e3 + A, E2 + E3 + A
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This gives the same three process components as above, but \whizard\
 recognized that e.g. $e^- e^+ \to \mu^- \gamma$ is a vanishing
 process, hence the numbering is different:
 \begin{footnotesize}
 \begin{Verbatim}
 | Process component 'multi_tensor_i2': matrix element vanishes
 | Process component 'multi_tensor_i3': matrix element vanishes
 | Process component 'multi_tensor_i4': matrix element vanishes
 | Process component 'multi_tensor_i6': matrix element vanishes
 | Process component 'multi_tensor_i7': matrix element vanishes
 | Process component 'multi_tensor_i8': matrix element vanishes
 | ------------------------------------------------------------------------
 | Process [scattering]: 'multi_tensor'
 |   Library name  = 'default_lib'
 |   Process index = 1
 |   Process components:
 |     1: 'multi_tensor_i1':   e-, e+ => m-, m+ [omega]
 |     5: 'multi_tensor_i5':   e-, e+ => t-, t+ [omega]
 |     9: 'multi_tensor_i9':   e-, e+ => A, A [omega]
 | ------------------------------------------------------------------------
 \end{Verbatim}
 \end{footnotesize}
 Identical copies of the same process that would be created by
 expanding the tensor product of final states are eliminated and appear
 only once in the final sum of process components.
 
 Naturally, inclusive process definitions are also available for
 decays:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 process multi_dec = Wp => E2 + E3, n2 + n3
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 This yields:
 \begin{footnotesize}
 \begin{Verbatim}
 | Process component 'multi_dec_i2': matrix element vanishes
 | Process component 'multi_dec_i3': matrix element vanishes
 | ------------------------------------------------------------------------
 | Process [decay]: 'multi_dec'
 |   Library name  = 'default_lib'
 |   Process index = 2
 |   Process components:
 |     1: 'multi_dec_i1':   W+ => mu+, numu [omega]
 |     4: 'multi_dec_i4':   W+ => tau+, nutau [omega]
 | ------------------------------------------------------------------------
 \end{Verbatim}
 \end{footnotesize}
 
 
 %%%%%%%%%%%%%%%
 
 \subsection{Compilation}
 \label{sec:compilation}
 
 Once processes have been set up, to make them available for integration they
 have to be compiled.  More precisely, the matrix-element generator
 \oMega\ (and it works similarly if a different matrix element method
 is chosen) is called to generate matrix element code, the compiler is
 called to transform this \fortran\ code into object files, and the
 linker is called to collect this in a dynamically loadable library.
 Finally, this library is linked to the program. From version v2.2.0 of
 \whizard\ this is no longer done by system calls of the OS but steered
 via process library Makefiles. Hence, the user can execute and
 manipulate those Makefiles in order to manually intervene in the
 particular steps, if he/she wants to do so.
 
 All this is done automatically when an \ttt{integrate}, \ttt{unstable}, or
 \ttt{simulate} command is encountered for the first time.  You may also force
 compilation explicitly by the command
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   compile
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 which performs all steps as listed above, including loading the generated
 library.
 
 The \fortran\ part of the compilation will be done using the \fortran\ compiler
 specified by the string variable
 \verb|$fc| and the compiler flags specified as \verb|$fcflags|.  The default
 settings are those that have been used for compiling \whizard\ itself during
 installation.  For library compatibility, you should stick to the compiler.
 The flags may be set differently.  They are applied in the compilation and
 loading steps, and they are processed by \ttt{libtool}, so
 \ttt{libtool}-specific flags can also be given.
 
 \whizard\ has some precautions against unnecessary repetitions.  Hence, when a
 \ttt{compile} command is executed (explicitly, or implicitly by the first
 integration), the program checks first whether the library is already loaded,
 and whether source code already exists for the requested processes.  If yes,
 this code is used and no calls to \oMega\ (or another matrix element
 method) or to the compiler are issued.
 Otherwise, it will detect any modification to the process configuration and
 regenerate the matrix element or recompile accordingly.  Thus, a \sindarin\
 script can be executed repeatedly without rebuilding everything from scratch,
 and you can safely add more processes to a script in a subsequent run without
 having to worry about the processes that have already been treated.
 
 This default behavior can be changed.  By setting
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   ?rebuild_library = true
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 code will be re-generated and re-compiled even if \whizard\ would think that
 this is unncessary.  The same effect is achieved by calling \whizard\ with a
 command-line switch,
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   /home/user$ whizard --rebuild_library
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 There are further \ttt{rebuild} switches which are described below.  If
 everything is to be rebuilt, you can set a master switch \ttt{?rebuild} or the
 command line option \verb|--rebuild|.  The latter can be abbreviated as a short
 command-line option:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   /home/user$ whizard -r
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Setting this switch is always a good idea when starting a new project, just in
 case some old files clutter the working directory.  When re-running the same
 script, possibly modified, the \verb|-r| switch should be omitted, so the
 existing files can be reused.
 
 
 
 \subsection{Process libraries}
 
 Processes are collected in \emph{libraries}.  A script may use more than one
 library, although for most applications a single library will probably be
 sufficient.
 
 The default library is \ttt{default\_lib}.  If you do not specify anything else,
 the processes you compile will be collected by a driver file
 \ttt{default\_lib.f90} which is compiled together with the process code and
 combined as a libtool archive \ttt{default\_lib.la}, which is dynamically linked
 to the running \whizard\ process.
 
 Once in a while, you work on several projects at once, and you didn't care
 about opening a new working directory for each.  If the \verb|-r| option is
 given, a new run will erase the existing library, which may contain processes
 needed for the other project.  You could omit \verb|-r|, so all processes will
 be collected in the same library (this does not hurt), but you may wish to
 cleanly separate the projects.  In that case, you should open a separate
 library for each project.
 
 Again, there are two possibilities.  You may start the script with the
 specification
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   library = "my_lhc_proc"
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 to open a library \verb|my_lhc_proc| in place of the default library.
 Repeating the command with different arguments, you may introduce several
 libraries in the script.  The active library is always the one specified
 last.  It is possible to issue this command locally, so a particular process
 goes into its own library.
 
 Alternatively, you may call \whizard\ with the option
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   /home/user$ whizard --library=my_lhc_proc
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 If several libraries are open simultaneously, the \ttt{compile} command will
 compile all libraries that the script has referenced so far.  If this is not
 intended, you may give the command an argument,
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   compile ("my_lhc_proc", "my_other_proc")
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 to compile only a specific subset.
 
 The command
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   show (library)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 will display the contents of the actually loaded library together with
 a status code which indicates the status of the library and the processes within.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Stand-alone \whizard\ with precompiled processes}
 \label{sec:static}
 
 Once you have set up a process library, it is straightforward to make a
 special stand-alone \whizard\ executable which will have this library
 preloaded on startup.  This is a matter of convenience, and it is also useful
 if you need a statically linked executable for reasons of profiling,
 batch processing, etc.
 
 For this task, there is a variant of the \ttt{compile} command:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   compile as "my_whizard" ()
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 which produces an executable \verb|my_whizard|.  You can omit the library
 argument if you simply want to include everything.  (Note that this command
 will \emph{not} load a library into the current process, it is intended for
 creating a separate program that will be started independently.)
 
 As an example, the script
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   process proc1 = e1, E1 => e1, E1
   process proc2 = e1, E1 => e2, E2
   process proc3 = e1, E1 => e3, E3
   compile as "whizard-leptons" ()
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 will make a new executable program \verb|whizard-leptons|.  This
 program behaves completely identical to vanilla \whizard, except for the fact
 that the processes \ttt{proc1}, \ttt{proc2}, and \ttt{proc3} are available
 without configuring them or loading any library.
 
 % This feature is particularly useful when compiling with the \ttt{-static}
 % flag.  As long as the architecture is compatible, the resulting binary may be
 % run on a different computer where no \whizard\ libraries are present.  (The
 % program will still need to find its model files, however.)
 
 
 
 \section{Beams}
 \label{sec:beams}
 
 Before processes can be integrated and simulated, the program has to know
 about the collider properties.  They can be specified by the \ttt{beams}
 statement.
 
 In the command script, it is irrelevant whether a \ttt{beams} statement comes
 before or after process specification.  The \ttt{integrate} or \ttt{simulate}
 commands will use the \ttt{beams} statement that was issued last.
 
 
 \subsection{Beam setup}
 \label{sec:beam-setup}
 
 If the beams have no special properties, and the colliding particles are the
 incoming particles in the process themselves, there is no need for a
 \ttt{beams} statement at all.  You only \emph{must} specify the
 center-of-momentum energy of the collider by setting the value of $\sqrt{s}$,
 for instance
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   sqrts = 14 TeV
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The \ttt{beams} statement comes into play if
 \begin{itemize}
 \item
   the beams have nontrivial structure, e.g., parton structure in hadron
   collision or photon radiation in lepton collision, or
 \item
   the beams have non-standard properties: polarization, asymmetry, crossing
   angle.
 \end{itemize}
 Note that some of the abovementioned beam properties had not yet been
 reimplemented in the \whizard\ttt{2} release series. From version
 v2.2.0 on all options of the legacy series \whizard\ttt{1} are
 available again. From version v2.1 to version v2.2 of \whizard\ there
 has also been a change in possible options to the \ttt{beams}
 statement: in the early versions of \whizard\ttt{2} (v2.0/v2.1), local
 options could be specified within the beam settings, e.g. \ttt{beams =
 p, p { sqrts = 14 TeV } => pdf\_builtin}. These possibility has been
 abandoned from version v2.2 on, and the \ttt{beams} command does not
 allow for {\em any} optional arguments any more.
 
 Hence, beam parameters can -- with the exception of the specification
 of structure functions -- be specified only globally:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   sqrts = 14 TeV
   beams = p, p => lhapdf
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 It does not make any difference whether the value of \ttt{sqrts} is
 set before or after the \ttt{beams} statement, the last value found
 before an \ttt{integrate} or \ttt{simulate} is the relevant one. This
 in particularly allows to specify the beam structure, and then after
 that perform a loop or scan over beam energies, beam parameters, or
 structure function settings.
 
 The \ttt{beams} statement also applies to particle decay processes, where there
 is only a single beam.  Here, it is usually redundant because no structure
 functions are possible, and the energy is fixed to the decaying particle's
 mass.  However, it is needed for computing polarized decay, e.g.
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = Z
   beams_pol_density = @(0)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 where for a boson at rest, the polarization axis is defined to be the $z$
 axis.
 
 Beam polarization is described in detail below in Sec.~\ref{sec:polarization}.
 
 Note also that future versions of \whizard\ might give support for
 single-beam events, where structure functions for single particles
 indeed do make sense.
 
 In the following sections we list the available options for structure
 functions or spectra inside \whizard\ and explain their usage. More
 about the physics of the implemented structure functions can be found
 in Chap.~\ref{chap:hardint}.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Asymmetric beams and Crossing angles}
 \label{sec:asymmetricbeams}
 
 \whizard\ not only allows symmetric beam collisions, but basically
 arbitrary collider setups. In the case there are two different beam
 energies, the command
 \begin{quote}
 \begin{footnotesize}
   \ttt{beams\_momentum = {\em <beam\_mom1>}, {\em <beam\_mom2>}}
 \end{footnotesize}
 \end{quote}
 allows to specify the momentum (or as well energies for massless
 particles) for the beams. Note that for scattering processes both
 values for the beams must be present. So the following to setups for
 14 TeV LHC proton-proton collisions are equivalent:
 \begin{quote}
 \begin{footnotesize}
   \ttt{beams = p, p => pdf\_builtin} \newline
   \ttt{sqrts = 14 TeV}
 \end{footnotesize}
 \end{quote}
 and
 \begin{quote}
 \begin{footnotesize}
   \ttt{beams = p, p => pdf\_builtin} \newline
   \ttt{beams\_momentum = 7 TeV, 7 TeV}
 \end{footnotesize}
 \end{quote}
 Asymmetric setups can be set by using different values for the two
 beam momenta, e.g. in a HERA setup:
 \begin{quote}
 \begin{footnotesize}
   \ttt{beams = e, p => none, pdf\_builtin}
   \ttt{beams\_momentum = 27.5 GeV, 920 GeV}
 \end{footnotesize}
 \end{quote}
 or for the BELLE experiment at the KEKB accelerator:
 \begin{quote}
 \begin{footnotesize}
   \ttt{beams = e1, E1}
   \ttt{beams\_momentum = 8 GeV, 3.5 GeV}
 \end{footnotesize}
 \end{quote}
 \whizard\ lets you know about the beam structure and calculates for
 you that the center of mass energy corresponds to 10.58 GeV:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 | Beam structure: e-, e+
 |   momentum = 8.000000000000E+00, 3.500000000000E+00
 | Beam data (collision):
 |   e-  (mass = 5.1099700E-04 GeV)
 |   e+  (mass = 5.1099700E-04 GeV)
 |   sqrts = 1.058300530253E+01 GeV
 | Beam structure: lab and c.m. frame differ
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 
 It is also possible to specify beams for decaying particles, where
 \ttt{beams\_momentum} then only has a single argument, e.g.:
 \begin{quote}
 \begin{footnotesize}
   \ttt{process zee = Z => "e-", "e+"} \\
   \ttt{beams = Z} \\
   \ttt{beams\_momentum = 500 GeV} \\
   \ttt{simulate (zee) \{ n\_events = 100 \} }
 \end{footnotesize}
 \end{quote}
 This would corresponds to a beam of $Z$ bosons with a momentum of 500
 GeV. Note, however, that \whizard\ will always do the integration of
 the particle width in the particle's rest frame, while the moving beam
 is then only taken into account for the frame of reference for the
 simulation.
 
 Further options then simply having different beam energies describe a
 non-vanishing between the two incoming beams. Such concepts are quite
 common e.g. for linear colliders to improve the beam properties in the
 collimation region at the beam interaction points. Such crossing
 angles can be specified in the beam setup, too, using the
 \ttt{beams\_theta} command:
 \begin{quote}
 \begin{footnotesize}
   \ttt{beams = e1, E1} \\
   \ttt{beams\_momentum = 500 GeV, 500 GeV} \\
   \ttt{beams\_theta = 0, 10 degree}
 \end{footnotesize}
 \end{quote}
 It is important that when a crossing angle is being specified, and the
 collision system consequently never is the center-of-momentum system,
 the beam momenta have to explicitly set. Besides a planar crossing
 angle, one is even able to rotate an azimuthal distance:
 \begin{quote}
 \begin{footnotesize}
   \ttt{beams = e1, E1} \\
   \ttt{beams\_momentum = 500 GeV, 500 GeV} \\
   \ttt{beams\_theta = 0, 10 degree} \\
   \ttt{beams\_phi = 0, 45 degree}
 \end{footnotesize}
 \end{quote}
 
 %%%%%%%%%%%%%%%
 
 \subsection{LHAPDF}
 \label{sec:lhapdf}
 
 For incoming hadron beams, the \ttt{beams} statement specifies which structure
 functions are used.  The simplest example is the study of parton-parton
 scattering processes at a hadron-hadron collider such as LHC or Tevatron.  The
 \lhapdf\ structure function set is selected by a syntax similar to the
 process setup, namely the example already shown above:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = p, p => lhapdf
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Note that there are slight differences in using the \lhapdf\ release
 series 6 and the older \fortran\ \lhapdf\ release series 5, at least
 concerning the naming conventions for the PDF sets~\footnote{Until
   \whizard\ version 2.2.1 including, only the \lhapdf\ series 5 was
   supported, while from version 2.2.2 on also the \lhapdf\ release
   series 6 has been supported.}. The above \ttt{beams}
 statement selects a default \lhapdf\ structure-function set for both
 proton beams (which is the \ttt{CT10} central set for \lhapdf\ 6, and
 \ttt{cteq6ll.LHpdf} central set for \lhapdf 5).  The structure
 function will apply for all quarks, antiquarks, and the gluon as far
 as supported by the particular \lhapdf\ set.  Choosing a different set
 is done by adding the  filename as a local option to the \ttt{lhapdf}
 keyword:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = p, p => lhapdf
   $lhapdf_file = "MSTW2008lo68cl"
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 for the actual \lhapdf\ 6 series, and
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = p, p => lhapdf
   $lhapdf_file = "MSTW2008lo68cl.LHgrid"
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 for \lhapdf 5.Similarly, a member within the set is selected by the
 numeric variable \verb|lhapdf_member| (for both release series of \lhapdf).
 
 In some cases, different structure functions have to be chosen for the two
 beams.  For instance, we may look at $ep$ collisions:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = "e-", p => none, lhapdf
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Here, there is a list of two independent structure functions (each with its
 own option set, if applicable) which applies to the two beams.
 
 Another mixed case is $p\gamma$ collisions, where the photon is to be
 resolved as a hadron.  The simple assignment
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = p, gamma => lhapdf, lhapdf_photon
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 will be understood as follows: \whizard\ selects the appropriate default
 structure functions (here we are using \lhapdf\ 5 as an example as the
 support of photon and pion PDFs in \lhapdf\ 6 has been dropped),
 \ttt{cteq6ll.LHpdf} for the proton and
 \ttt{GSG960.LHgrid} for the photon.  The photon case has an additional
 integer-valued parameter \verb|lhapdf_photon_scheme|.  (There are also pion
 structure functions available.)  For modifying the default, you have to
 specify separate structure functions
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = p, gamma => lhapdf, lhapdf_photon
   $lhapdf_file = ...
   $lhapdf_photon_file = ...
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Finally, the scattering of elementary photons on partons is described by
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = p, gamma => lhapdf, none
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 Note that for \lhapdf\ version 5.7.1 or higher and for PDF sets which
 support it, photons can be used as partons.
 
 There is one more option for the \lhapdf\ PDFs, namely to specify the
 path where the \lhapdf\ PDF sets reside: this is done with the string
 variable \ttt{\$lhapdf\_dir = "{\em <path-to-lhapdf>}"}. Usually, it
 is not necessary to set this because \whizard\ detects this path via
 the \ttt{lhapdf-config} script during configuration, but in the case
 paths have been moved, or special files/special locations are to be
 used, the user can specify this location explicitly.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Built-in PDFs}
 \label{sec:built-in-pdf}
 
 In addition to the possibility of linking against \lhapdf, \whizard\
 comes with a couple of built-in PDFs which are selected via the
 \verb?pdf_builtin? keyword
 %
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = p, p => pdf_builtin
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 %
 
 The default PDF set is CTEQ6L, but other choices are also available by
 setting the string variable \verb?$pdf_builtin_set? to an
 appropiate value. E.g, modifying the above
 setup to
 %
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   beams = p, p => pdf_builtin
   $pdf_builtin_set = "mrst2004qedp"
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 %
 would select the proton PDF from the MRST2004QED set. A list of all currently
 available PDFs can be found in Table~\ref{tab:pdfs}.
 %
 \begin{table}
 \centerline{\begin{tabular}{|l||l|p{0.2\textwidth}|l|}
 \hline
 Tag & Name & Notes & References \\\hline\hline
 %
 \ttt{cteq6l} & CTEQ6L & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Pumplin:2002vw} \\\hline
 \ttt{cteq6l1} & CTEQ6L1 & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Pumplin:2002vw} \\\hline
 \ttt{cteq6d} & CTEQ6D & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Pumplin:2002vw} \\\hline
 \ttt{cteq6m} & CTEQ6M & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Pumplin:2002vw} \\\hline
 \hline
 \ttt{mrst2004qedp} & MRST2004QED (proton) & includes photon &
    \cite{Martin:2004dh} \\\hline
 \hline
 \ttt{mrst2004qedn} & MRST2004QED (neutron) & includes photon &
    \cite{Martin:2004dh} \\\hline
 \hline
 \ttt{mstw2008lo} & MSTW2008LO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Martin:2009iq} \\\hline
 \ttt{mstw2008nlo} & MSTW2008NLO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Martin:2009iq} \\\hline
 \ttt{mstw2008nnlo} & MSTW2008NNLO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Martin:2009iq} \\\hline
 \hline
 \ttt{ct10} & CT10 & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Lai:2010vv} \\\hline
 \hline
 \ttt{CJ12\_max} & CJ12\_max & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Owens:2012bv} \\\hline
 \ttt{CJ12\_mid} & CJ12\_mid & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Owens:2012bv} \\\hline
 \ttt{CJ12\_min} & CJ12\_min & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Owens:2012bv} \\\hline
 \hline
 \ttt{CJ15LO} & CJ15LO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Accardi:2016qay} \\\hline
 \ttt{CJ15NLO} & CJ15NLO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Accardi:2016qay} \\\hline
 \hline
 \ttt{mmht2014lo} & MMHT2014LO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Harland-Lang:2014zoa} \\\hline
 \ttt{mmht2014nlo} & MMHT2014NLO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Harland-Lang:2014zoa} \\\hline
 \ttt{mmht2014nnlo} & MMHT2014NNLO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Harland-Lang:2014zoa} \\\hline
 \hline
 \ttt{CT14LL} & CT14LLO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Dulat:2015mca} \\\hline
 \ttt{CT14L} & CT14LO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Dulat:2015mca} \\\hline
 \ttt{CT14N} & CT1414NLO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Dulat:2015mca} \\\hline
 \ttt{CT14NN} & CT14NNLO & \mbox{}\hfill---\hfill\mbox{} &
    \cite{Dulat:2015mca} \\\hline
 \hline
 %
 \end{tabular}}
 \caption{All PDF sets available as builtin sets. The two MRST2004QED
   sets also contain a photon.}
 \label{tab:pdfs}
 \end{table}
 
 The two MRST2004QED sets also contain the photon as a parton, which
 can be used in the same way as for \lhapdf\ from v5.7.1 on. Note,
 however, that there is no builtin PDF that contains a photon structure
 function. There is a \ttt{beams} structure function specifier
 \ttt{pdf\_builtin\_photon}, but at the moment this throws an error. It
 just has been implemented for the case that in future versions of
 \whizard\ a photon structure function might be included.
 
 Note that in general only the data sets for the central values of the
 different PDFs ship with \whizard. Using the error sets is possible,
 i.e. it is supported in the syntax of the code, but you have to
 download the corresponding data sets from the web pages of the PDF
 fitting collaborations.
 
 %%%%%%%%%%%%%%%
 
 \subsection{HOPPET $b$ parton matching}
 
 When the \hoppet\ tool~\cite{Salam:2008qg} for hadron-collider PDF
 structure functions and their manipulations are
 correctly linked to \whizard, it can be used for advanced
 calculations and simulations of hadron collider physics. Its main
 usage inside \whizard\ is for matching schemes between 4-flavor and
 5-flavor schemes in $b$-parton initiated processes at hadron
 colliders. Note that in versions 2.2.0 and 2.2.1 it only worked
 together with \lhapdf\ version 5, while with the \lhapdf\ version 6
 interface from version 2.2.2 on it can be used also with the modern
 version of PDFs from \lhapdf. Furthermore, from version 2.2.2, the
 \hoppet\ $b$ parton matching also works for the builtin PDFs.
 
 It depends on the corresponding process and the energy scales involved
 whether it is a better description to use the
 $g\to b\bar b$ splitting from the DGLAP evolution inside the PDF and
 just take the $b$ parton content of a PDF, e.g. in BSM Higgs
 production for large $\tan\beta$: $pp \to H$ with a partonic
 subprocess $b\bar b \to H$, or directly take the gluon PDFs and use
 $pp \to b\bar b H$ with a partonic subprocess $gg \to b \bar b
 H$. Elaborate schemes for a proper matching between the two
 prescriptions have been developed and have been incorporated into the
 \hoppet\ interface.
 
 Another prime example for using these matching schemes is single top
 production at hadron colliders. Let us consider the following setup:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 process proc1 = b, u => t, d
 process proc2 = u, b => t, d
 process proc3 = g, u => t, d, B	{ $restrictions = "2+4 ~ W+" }
 process proc4 = u, g => t, d, B	{ $restrictions = "1+4 ~ W+" }
 
 beams = p,p => pdf_builtin
 sqrts = 14 TeV
 ?hoppet_b_matching = true
 
 $sample = "single_top_matched"
 luminosity = 1 / 1 fbarn
 simulate (proc1, proc2, proc3, proc4)
 \end{Verbatim}
 \end{footnotesize}%$
 \end{quote}
 The first two processes are single top production from $b$ PDFs, the
 last two processes contain an explicit $g\to b\bar b$ splitting (the
 restriction, cf. Sec.~\ref{sec:process options} has been placed in
 order to single out the single top production signal process). PDFs
 are then chosen from the default builtin PDF (which is \ttt{CTEQ6L}),
 and the \hoppet\ matching routines are switched on by the flag
 \ttt{?hoppet\_b\_matching}.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Lepton Collider ISR structure functions}
 \label{sec:lepton_isr}
 
 Initial state QED radiation off leptons is an important feature at all
 kinds of lepton colliders: the radiative return to the $Z$ resonance
 by ISR radiation was in fact the largest higher-order effect for the
 SLC and LEP I colliders. The soft-collinear and soft photon radiation
 can indeed be resummed/exponentiated to all orders in perturbation
 theory~\cite{Gribov:1972rt}, while higher orders in hard-collinear
 photons have to be explicitly calculated order by
 order~\cite{Kuraev:1985hb,Skrzypek:1990qs}. \whizard\ has an intrinsic
 implementation of the lepton ISR structure function that includes all
 orders of soft and soft-collinear photons as well as up to the third
 order in hard-collinear photons. It can be switched on by the
 following statement:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 beams = e1, E1 => isr
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 As the ISR structure function is a single-beam structure function,
 this expression is synonymous for
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 beams = e1, E1 => isr, isr
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 The ISR structure function can again be applied to only one of the two
 beams, e.g. in a HERA-like setup:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 beams = e1, p => isr, pdf_builtin
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 
 Their are several options for the lepton-collider ISR structure
 function that are summarized in the following:
 
 \vspace{2mm}
 
 \centerline{\begin{tabular}{|l|l|l|}\hline
 Parameter & Default & Meaning \\\hline\hline
 \ttt{isr\_alpha} & \ttt{0}/intrinsic & value of $\alpha_{QED}$ for ISR
 \\\hline
 \ttt{isr\_order} & \ttt{3} & max. order of hard-collinear photon
 emission \\\hline
 \ttt{isr\_mass} & \ttt{0}/intrinsic & mass of the radiating lepton  \\\hline
 \ttt{isr\_q\_max} & \ttt{0}/$\sqrt{s}$ & upper cutoff for ISR \\\hline
 \hline
 \ttt{?isr\_recoil} & \ttt{false} & flag to switch on recoil/$p_T$
 (\emph{deprecated})\\\hline
 \ttt{?isr\_keep\_energy} & \ttt{false} & recoil flag: conserve
 energy in splitting (\emph{deprecated})
 \\\hline
 \end{tabular}}\mbox{}
 
 The maximal order of the hard-collinear photon emission taken into
 account by \whizard\ is set by the integer variable \ttt{isr\_order};
 the default is the maximally available order of three. With the
 variable \ttt{isr\_alpha}, the value of the QED coupling constant
 $\alpha_{QED}$ used in the ISR structure function can be set. The
 default is taken from the active physics model. The mass of the
 radiating lepton (in most cases the electron) is set by
 \ttt{isr\_mass}; again the default is taken from the active physics
 model. Furthermore, the upper integration border for the ISR structure
 function which acts roughly as an upper hardness cutoff for the emitted
 photons, can be set through \ttt{isr\_q\_max}; if not set, the
 collider energy (possibly after beamstrahlung,
 cf. Sec.~\ref{sec:beamstrahlung}) $\sqrt{s}$ (or $\sqrt{\widehat{s}}$)
 is taken.  Note that \whizard\ accounts for the
 exclusive effects of ISR radiation at the moment by a single (hard,
 resolved) photon in the event; a more realistic treatment of exclusive
 ISR photons in simulation is foreseen for a future version.
 
 While the ISR structure function is evaluated in the collinear limit,
 it is possible to generate transverse momentum for both the radiated
 photons and the recoiling partonic system.  We recommend to stick to
 the collinear approximation for the integration step.  Integration
 cuts should be set up such that they do not significantly depend on
 photon transverse momentum.  In a subsequent simulation step, it is
 possible to transform the events with collinear ISR radiation into
 more realistic events with non-collinear radiation.  To this end,
 \whizard\ provides a separate ISR photon handler which can be
 activated in the simulation step.  The algorithm operates on the
 partonic event: it takes the radiated photons and the partons entering
 the hard process, and applies a $p_T$ distribution to those particles
 and their interaction products, i.e., all outgoing particles.  Cuts
 that depend on photon $p_T$ may be applied to the modified events.
 For details on the ISR photon handler,
 cf.\ Sec.~\ref{sec:isr-photon-handler}.
 
 {\footnotesize The flag \ttt{?isr\_recoil} switches on $p_T$ recoil of
   the emitting lepton against photon radiation during integration; per
   default it is off.  The flag \ttt{?isr\_keep\_energy} controls the
   mode of on-shell projection for the splitting process with $p_T$.
   Note that this feature is kept for backwards compatibility, but
   should not be used for new simulations.  The reason is as follows:
   For a fraction of events, $p_T$ will become significant, and (i)
   energy/momentum non-conservation, applied to both beams separately,
   can lead to unexpected and unphysical effects, and (ii) the modified
   momenta enter the hard process, so the collinear approximation used
   in the ISR structure function computation does not hold.  }
 
 %%%%%%%%%%%%%%%
 
 \subsection{Lepton Collider Beamstrahlung}
 \label{sec:beamstrahlung}
 
 At linear lepton colliders, the macroscopic electromagnetic
 interaction of the bunches leads to a distortion of the spectrum of
 the bunches that is important for an exact simulation of the beam
 spectrum. There are several methods to account for these effects. The
 most important tool to simulate classical beam-beam interactions in
 lepton-collider physics is
 \ttt{GuineaPig++}~\cite{Schulte:1998au,Schulte:1999tx,Schulte:2007zz}. A
 direct interface between this tool \ttt{GuineaPig++} and \whizard\ had
 existed as an inofficial add-on to the legacy branch \whizard\ttt{1},
 but is no longer applicable in \whizard\ttt{2}. A \whizard-internal
 interface is foreseen for the very near future, most probably within
 this v2.2 release. Other options are to use parameterizations of the
 beam spectrum that have been included in the package \circeone~\cite{CIRCE}
 which has been interfaced to \whizard\ since version v1.20 and been
 included in the \whizard\ttt{2} release series. Another option is to
 generate a beam spectrum externally and then read it in as an ASCII
 data file, cf. Sec.~\ref{sec:beamevents}. More about this can be found
 in a dedicated section on lepton collider spectra,
 Sec.~\ref{sec:beamspectra}.
 
 In this section, we discuss the usage of beamstrahlung spectra by
 means of the \circeone\ package. The beamstrahlung spectra are
 true spectra, so they have to be applied to pairs of beams, and an
 application to only one beam is meaningless. They are switched on by
 this \ttt{beams} statement including structure functions:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 beams = e1, E1 => circe1
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 It is important to note that the parameterization of the beamstrahlung
 spectra within \circeone\ contain also processes where $e\to\gamma$
 conversions have been taking place, i.e. also hard processes with one
 (or two) initial photons can be simulated with beamstrahlung switched
 on. In that case, the explicit photon flags, \ttt{?circe1\_photon1}
 and \ttt{?circe1\_photon2}, for the two beams have to be properly set,
 e.g. (ordering in the final state does not play a role):
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 process proc1 = A, e1 => A, e1
 sqrts = 500 GeV
 beams = e1, E1 => circe1
 ?circe1_photon1 = true
 integrate (proc1)
 
 process proc2 = e1, A => A, e1
 sqrts = 1000 GeV
 beams = e1, A => circe1
 ?circe1_photon2 = true
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 or
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 process proc1 = A, A => Wp, Wm
 sqrts = 200 GeV
 beams = e1, E1 => circe1
 ?circe1_photon1 = true
 ?circe1_photon2 = true
 ?circe1_generate = false
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 In all cases (one or both beams with photon conversion) the beam
 spectrum applies to both beams simultaneously.
 
 In the last example ($\gamma\gamma\to W^+W^-$) the default
 \circeone\ generator mode was turned off by unsetting
 \verb|?circe1_generate|.  In the other examples this flag is
 set, by default.  For standard use cases,
 \circeone\ implements a beam-event generator inside the
 \whizard\ generator, which provides beam-event samples with correctly
 distributed probability.  For electrons, the beamstrahlung spectrum
 sharply peaks near maximum energy.  This distribution is most
 efficiently handled by the generator mode.  By contrast, in the $\gamma\gamma$
 mode, the beam-event c.m.\ energy is concentrated at low values.  For
 final states with low invariant mass, which are typically produced by
 beamstrahlung photons, the generator mode is appropriate.
 However, the $W^+W^-$ system requires substantial energy, and such
 events will be very rare in the beam-event sample.  Switching off the
 \circeone\ generator mode solves this
 problem.
 
 This is an overview over all options and flags for the \circeone\
 setup for lepton collider beamstrahlung:
 
 \vspace{2mm}
 
 \centerline{\begin{tabular}{|l|l|l|}\hline
 Parameter & Default & Meaning \\\hline\hline
 \ttt{?circe1\_photon1} & \ttt{false} & $e\to\gamma$ conversion for beam 1
 \\\hline
 \ttt{?circe1\_photon2} & \ttt{false} & $e\to\gamma$ conversion for beam 2
 \\\hline
 \ttt{circe1\_sqrts} & $\sqrt{s}$ & collider energy for the beam spectrum  \\\hline
 \ttt{?circe1\_generate} & \ttt{true} & flag for the \circeone\ generator mode \\\hline
 \ttt{?circe1\_map} & \ttt{true} & flag to apply special phase-space mapping
 \\\hline
 \ttt{circe1\_mapping\_slope} & \ttt{2.} & value of PS mapping exponent
 \\\hline
 \ttt{circe1\_eps} & \ttt{1E-5} & parameter for mapping of spectrum peak
 position \\\hline
 \ttt{circe1\_ver} & \ttt{0} & internal version of \circeone\ package
 \\\hline
 \ttt{circe1\_rev} & \ttt{0}/most recent & internal revision of
 \circeone\ \\\hline
 \ttt{\$circe1\_acc} & \ttt{SBAND} & accelerator type \\\hline
 \ttt{circe1\_chat} & \ttt{0} & chattiness/verbosity of \circeone \\\hline
 \end{tabular}}\mbox{}
 
 The collider energy relevant for the beamstrahlung spectrum is set by
 \ttt{circe1\_sqrts}. As a default, this is always the value of
 \ttt{sqrts} set in the \sindarin\ script. However, sometimes these
 values do not match, e.g. the user wants to simulate $t\bar t h$ at
 \ttt{sqrts = 550 GeV}, but the only available beam spectrum is for 500
 GeV. In that case, \ttt{circe1\_sqrts = 500 GeV} has to be set to use
 the closest possible available beam spectrum.
 
 As mentioned in the discussion of the examples above, in
 \circeone\ there are two options to use the beam spectra for
 beamstrahlung: intrinsic semi-analytic approximation formulae for the
 spectra, or a Monte-Carlo sampling of the sampling. The second
 possibility always give a better description of the spectra, and is
 the default for \whizard. It can, however, be switched off by setting
 the flag \ttt{?circe1\_generate} to \ttt{false}.
 
 As the beamstrahlung spectra are sharply peaked at the collider
 energy, but still having long tails, a mapping of the spectra for an
 efficient phase-space sampling is almost mandatory. This is the
 default in \whizard, which can be changed by the flag
 \ttt{?circe1\_map}. Also, the default exponent for the mapping can be
 changed from its default value \ttt{2.} with the variable
 \ttt{circe1\_mapping\_slope}. It is important to efficiently sample
 the peak position of the spectrum; the effective ratio of the peak to
 the whole sampling interval can be set by the parameter
 \ttt{circe1\_eps}. The integer parameter \ttt{circe1\_chat} sets the
 chattiness or verbosity of the \circeone\ package, i.e. how many
 messages and warnings from the beamstrahlung generation/sampling will
 be issued.
 
 The actual internal version and revision of the \circeone\ package are
 set by the two integer parameters \ttt{circe1\_ver} and
 \ttt{circe1\_rev}. The default is in any case always the newest
 version and revision, while older versions are still kept for
 backwards compatibility and regression testing.
 
 Finally, the geometry and design of the accelerator type is set with
 the string variable \ttt{\$circe1\_acc}: it contains the possible
 options for the old \ttt{"SBAND"} and \ttt{"XBAND"} setups, as well as
 the \ttt{"TESLA"} and JLC/NLC SLAC design \ttt{"JLCNLC"}. The setups
 for the most important energies of the ILC as they are summarized in
 the ILC
 TDR~\cite{Behnke:2013xla,Baer:2013cma,Adolphsen:2013jya,Adolphsen:2013kya}
 are available as \ttt{ILC}. Beam spectra for the
 CLIC~\cite{Aicheler:2012bya,Lebrun:2012hj,Linssen:2012hp} linear
 collider are much more demanding to correctly simulate (due to the
 drive beam concept; only the low-energy modes where the drive beam is
 off can be simulated with the same setup as the abovementioned
 machines). Their setup will be supported soon in one of the upcoming
 \whizard\ versions within the \circetwo\ package.
 
 An example of how to generate beamstrahlung spectra with the help of
 the package \circetwo\ (that is also a part of \whizard) is this:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 process eemm = e1, E1 => e2, E2
 sqrts = 500 GeV
 beams = e1, E1 => circe2
 $circe2_file = "ilc500.circe"
 $circe2_design = "ILC"
 ?circe_polarized = false
 \end{Verbatim}
 \end{footnotesize}%$
 \end{quote}
 Here, the ILC design is used for a beamstrahlung spectrum at 500 GeV
 nominal energy, with polarization averaged (hence, the setting of
 polarization to \ttt{false}). A list of all available options can be
 found in Sec.~\ref{sec:photoncoll}.
 
 More technical details about the simulation of beamstrahlung spectra
 see the documented source code of the \circeone\ package, as well as
 Chap.~\ref{chap:hardint}. In the next section, we discuss how to read
 in beam spectra from external files.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Beam events}
 \label{sec:beamevents}
 
 As mentioned in the previous section, beamstrahlung is one of the
 crucial ingredients for a realistic simulation of linear lepton
 colliders. One option is to take a pre-generated beam spectrum for
 such a machine, and make it available for simulation within \whizard\
 as an external ASCII data file. Such files basically contain only
 pairs of energy fractions of the nominal collider energy $\sqrt{s}$
 ($x$ values). In \whizard\ they can be used in simulation with the
 following \ttt{beams} statement:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 beams = e1, E1 => beam_events
 $beam_events_file = "<beam_spectrum_file>"
 \end{Verbatim}
 \end{footnotesize}%$
 \end{quote}
 Note that beam spectra must always be pair spectra, i.e. they are
 automatically applied to both beam simultaneously.
 Beam spectra via external files are expected to reside in the current
 working directory. Alternatively, \whizard\ searches for them in the
 install directory of \whizard\ in \ttt{share/beam-sim}. There you can
 find an example file, \ttt{uniform\_spread\_2.5\%.dat} for such a beam
 spectrum. The only possible parameter that can be set is the flag
 \ttt{?beam\_events\_warn\_eof} whose default is \ttt{true}. This
 triggers the issuing of a warning when the end of file of an external
 beam spectrum file is reached. In such a case, \whizard\ starts to
 reuse the same file again from the beginning. If the available data
 points in the beam events file are not big enough, this could result
 in an insufficient sampling of the beam spectrum.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Gaussian beam-energy spread}
 \label{sec:gaussian}
 
 Real beams have a small energy spread.  If beamstrahlung is small, the spread
 may be approximately described as Gaussian.  As a replacement for the full
 simulation that underlies \ttt{CIRCE2} spectra, it is possible to
 impose a Gaussian distributed beam energy, separately for each beam.
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 beams = e1, E1 => gaussian
 gaussian_spread1 = 0.1\%
 gaussian_spread2 = 0.2\%
 \end{Verbatim}
 \end{footnotesize}%$
 \end{quote}
 (Note that the \% sign means multiplication by 0.01, as it should.)  The
 spread values are defined as the $\sigma$ value of the Gaussian distribution,
 i.e., $2/3$ of the events are within $\pm 1\sigma$ for each beam,
 respectively.
 
 %%%%%%%%%%%%%%%%
 
 \subsection{Equivalent photon approximation}
 \label{sec:epa}
 
 The equivalent photon approximation (EPA) uses an on-shell approximation for
 the $e \to e\gamma$ collinear splitting to allow the simulation of
 photon-induced backgrounds in lepton collider physics. The original
 concept is that of the Weizs\"acker-Williams
 approximation~\cite{vonWeizsacker:1934sx,Williams:1934ad,Budnev:1974de}. This
 is a single-beam structure
 function that can be applied to both beams, or also to one beam
 only. Examples are:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 beams = e1, E1 => epa
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 or for a single beam:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 beams = e1, p => epa, pdf_builtin
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 The last process allows the reaction of (quasi-) on-shell photons with
 protons.
 
 In the following, we collect the parameters and flags that can be
 adjusted when using the EPA inside \whizard:
 
 \vspace{2mm}
 
 \centerline{\begin{tabular}{|l|l|l|}\hline
 Parameter & Default & Meaning \\\hline\hline
 \ttt{epa\_alpha} & \ttt{0}/intrinsic & value of $\alpha_{QED}$ for EPA
 \\\hline
 \ttt{epa\_x\_min} & \ttt{0.} & soft photon cutoff in $x$ (mandatory)
 \\\hline
 \ttt{epa\_q\_min} & \ttt{0.} & minimal $\gamma$ momentum transfer \\\hline
 \ttt{epa\_mass} & \ttt{0}/intrinsic & mass of the radiating fermion (mandatory)  \\\hline
 \ttt{epa\_q\_max} & \ttt{0}/$\sqrt{s}$ & upper cutoff for EPA \\\hline
 \ttt{?epa\_recoil} & \ttt{false} & flag to switch on recoil/$p_T$
 \\\hline
 \ttt{?epa\_keep\_energy} & \ttt{false} & recoil flag to conserve
 energy in splitting
 \\\hline
 \end{tabular}}\mbox{}
 
 The adjustable parameters are partially similar to the parameters in
 the QED initial-state radiation (ISR), cf. Sec.~\ref{sec:lepton_isr}:
 the parameter \ttt{epa\_alpha} sets the value of the electromagnetic
 coupling constant, $\alpha_{QED}$ used in the EPA structure
 function. If not set, this is taken from the value inside the active
 physics model. The same is true for the mass of the particle that
 radiates the photon of the hard interaction, which can be reset by the
 user with the variable \ttt{epa\_mass}. There are two dimensionful
 scale parameters, the minimal momentum transfer to the photon,
 \ttt{epa\_q\_min}, which must not be zero, and the upper momentum-transfer
 cutoff
 for the EPA structure function, \ttt{epa\_q\_max}. The default for the
 latter value is the collider energy, $\sqrt{s}$, or the energy reduced
 by another structure function like e.g. beamstrahlung,
 $\sqrt{\hat{s}}$. Furthermore, there is a soft-photon regulator for
 the splitting function in $x$ space, \ttt{epa\_x\_min}, which also has
 to be explicitly set different from zero. Hence, a minimal viable
 scenario that will be accepted by \whizard\ looks like this:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 beams = e1, E1 => epa
 epa_q_min = 5 GeV
 epa_x_min = 0.01
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 
 Finally, like the ISR case in Sec.~\ref{sec:lepton_isr}, there is a
 flag to consider the recoil of the photon against the radiating
 electron by setting \ttt{?epa\_recoil} to \ttt{true} (default:
 \ttt{false}).
 
 Though in principle processes like $e^+ e^- \to e^+ e^- \gamma \gamma$
 where the two photons have been created almost collinearly and then
 initiate a hard process could be described by exact matrix elements
 and exact kinematics. However, the numerical stability in the very far
 collinear kinematics is rather challenging, such that the use of the
 EPA is very often an acceptable trade-off between quality of the
 description on the one hand and numerical stability and speed on the
 other hand.
 
 In the case, the EPA is set after a second structure function like a
 hadron collider PDF, there is a flavor summation over the quark
 constituents inside the proton, which are then the radiating fermions
 for the EPA. Here, the masses of all fermions have to be identical.
 
 More about the physics of the equivalent photon approximation can be
 found in Chap.~\ref{chap:hardint}.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Effective $W$ approximation}
 \label{sec:ewa}
 
 An approach similar to the equivalent photon approximation (EPA)
 discussed in the previous section Sec.~\ref{sec:epa}, is the usage
 of a collinear splitting function for the radiation of massive
 electroweak vector bosons $W$/$Z$, the effective $W$ approximation
 (EWA). It has been developed for the
 description of high-energy weak vector-boson fusion and scattering
 processes at hadron colliders, particularly the Superconducting
 Super-Collider (SSC). This was at a time when the simulation of $2\to
 4$ processes war still very challenging and $2\to 6$ processes almost
 impossible, such that this approximation was the only viable solution
 for the simulation of processes like $pp \to jjVV$ and subsequent
 decays of the bosons $V \equiv W, Z$.
 
 Unlike the EPA, the EWA is much more involved as the structure
 functions do depend on the isospin of the radiating fermions, and are
 also different for transversal and longitudinal polarizations. Also, a
 truely collinear kinematics is never possible due to the finite $W$
 and $Z$ boson masses, which start becoming more and more negligible
 for energies larger than the nominal LHC energy of 14 TeV.
 
 Though in principle all processes for which the EWA might be
 applicable are technically feasible in \whizard\ to be generated also
 via full matrix elements, the EWA has been implemented in \whizard\
 for testing purposes, backwards compatibility and comparison with
 older simulations. Like the EPA, it is a single-beam structure
 function that can be applied to one or both beams. We only give an
 example for both beams here, this is for a 3 TeV CLIC collider:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 sqrts = 3 TeV
 beams = e1, E1 => ewa
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 And this is for LHC or a higher-energy follow-up collider (which also
 shows the concatenation of the single-beam structure functions,
 applied to both beams consecutively,
 cf. Sec.~\ref{sec:concatenation}:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 sqrts = 14 TeV
 beams = p, p => pdf_builtin => ewa
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 
 Again, we list all the options, parameters and flags that can be
 adapted for the EWA:
 
 \vspace{2mm}
 
 \centerline{\begin{tabular}{|l|l|l|}\hline
 Parameter & Default & Meaning \\\hline\hline
 \ttt{ewa\_x\_min} & \ttt{0.} & soft $W$/$Z$ cutoff in $x$ (mandatory)
 \\\hline
 \ttt{ewa\_mass} & \ttt{0}/intrinsic & mass of the radiating fermion  \\\hline
 \ttt{ewa\_pt\_max} & \ttt{0}/$\sqrt{\hat{s}}$ & upper cutoff for EWA \\\hline
 \ttt{?ewa\_recoil} & \ttt{false} & recoil switch
 \\\hline
 \ttt{?ewa\_keep\_energy} & \ttt{false} & energy conservation for
 recoil in splitting
 \\\hline
 \end{tabular}}\mbox{}
 
 First of all, all coupling constants are taken from the active physics
 model as they have to be consistent with electroweak gauge
 invariance. Like for EPA, there is a soft $x$ cutoff for the $f \to f
 V$ splitting, \ttt{ewa\_x\_min}, that has to be set different from
 zero by the user. Again, the mass of the radiating fermion can be set
 explicitly by the user; and, also again, the masses for the flavor sum
 of quarks after a PDF as radiators of the electroweak bosons have to
 be identical. Also for the EWA, there is an upper cutoff for the $p_T$
 of the electroweak boson, that can be set via
 \ttt{eta\_pt\_max}. Indeed, the transversal $W$/$Z$ structure function
 is logarithmically divergent in that variable. If it is not set by the
 user, it is estimated from $\sqrt{s}$ and the splitting kinematics.
 
 For the EWA, there is a flag to switch on a recoil for the
 electroweak boson against the radiating fermion,
 \ttt{?ewa\_recoil}. Note that this is an experimental feature that is
 not completely tested. In any case, the non-collinear kinematics
 violates 4-four momentum conservation, so there are two choices:
 either to conserve the energy (\ttt{?ewa\_keep\_energy = true}) or to
 conserve 3-momentum (\ttt{?ewa\_keep\_energy = false}). Momentum
 conservation for the kinematics is the default. This is due to the
 fact that for energy conservation, there will be a net total momentum
 in the event including the beam remnants (ISR/EPA/EWA radiated
 particles) that leeds to unexpected or unphysical features in the
 energy distributions of the beam remnants recoiling against the rest
 of the event.
 
 More details about the physics can be found in
 Chap.~\ref{chap:hardint}.
 
 
 %%%%%%%%%%%%%%%
 
 \subsection{Energy scans using structure functions}
 
 In \whizard, there is an implementation of a pair spectrum,
 \ttt{energy\_scan}, that allows to scan the energy dependence of a
 cross section without actually scanning over the collider
 energies. Instead, only a single integration at the upper end of the
 scan interval over the process with an additional pair spectrum
 structure function performed. The structure function is chosen
 in such a way, that the distribution of $x$ values of the energy scan
 pair spectrum translates in a plot over the energy of the final state
 in an energy scan from \ttt{0} to \ttt{sqrts} for the process under
 consideration.
 
 The simplest example is the $1/s$ fall-off with the $Z$ resonance in
 $e^+e^- \to \mu^+ \mu^-$, where the syntax is very easy:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 process eemm = e1, E1 => e2, E2
 sqrts = 500 GeV
 cuts = sqrts_hat > 50
 beams = e1, E1 => energy_scan
 integrate (eemm)
 \end{Verbatim}
 \end{footnotesize}
 \end{quote}
 The value of \ttt{sqrts = 500 GeV} gives the upper limit for the scan,
 while the cut effectively let the scan start at 50 GeV. There are no
 adjustable parameters for this structure function. How to plot the
 invariant mass distribution of the final-state muon pair to show the
 energy scan over the cross section, will be explained in
 Sec.~\ref{sec:analysis}.
 
 More details can be found in Chap.~\ref{chap:hardint}.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Photon collider spectra}
 \label{sec:photoncoll}
 
 One option that has been discussed as an alternative possibility for a
 high-energy linear lepton collider is to convert the electron and
 positron beam via Compton backscattering off intense laser beams into
 photon
 beams~\cite{Ginzburg:1981vm,Telnov:1989sd,Telnov:1995hc}. Naturally,
 due to the production
 of the photon beams and the inherent electron spectrum, the photon
 beams have a characteristic spectrum. The simulation of such spectra
 is possible within \whizard\ by means of the subpackage \circetwo,
 which have been mentioned already in Sec.~\ref{sec:beamstrahlung}. It
 allows to give a much more elaborate description of a linear lepton
 collider environment than
 \circeone\ (which, however, is not in all cases necessary, as the ILC
 beamspectra for electron/positrons can be perfectly well described
 with \circeone).
 
 Here is a typical photon collider setup where we take a
 photon-initiated process:
 \begin{quote}
 \begin{footnotesize}
 \begin{Verbatim}
 process aaww = A, A => Wp, Wm
 
 beams = A, A => circe2
 $circe2_file = "teslagg_500_polavg.circe"
 $circe2_design = "TESLA/GG"
 ?circe2_polarized = false
 \end{Verbatim}
 \end{footnotesize}%$
 \end{quote}
 
 Here, the photons are the initial states initiating the hard
 scattering. The structure function is \ttt{circe2} which always is a
 pair spectrum. The list of available options are:
 
 \vspace{2mm}
 
 \centerline{\begin{tabular}{|l|l|l|}\hline
 Parameter & Default & Meaning \\\hline\hline
 \ttt{?circe2\_polarized} & \ttt{true} & spectrum respects polarization info
 \\\hline
 \ttt{\$circe2\_file} & -- & name of beam spectrum data file
 \\\hline
 \ttt{\$circe2\_design} & \ttt{"*"} & collider design
 \\\hline
 \end{tabular}}\mbox{}
 
 The only logical flag \ttt{?circe2\_polarized} let \whizard\ know
 whether it should keep polarization information in the beam spectra or
 average over polarizations. Naturally, because of the Compton
 backscattering generation of the photons, photon spectra are always
 polarized. The collider design can be specified by the string variable
 \ttt{\$circe2\_design}, where the default setting \ttt{"*"}
 corresponds to the default of \circetwo\ (which is the TESLA 500 GeV
 machine as discussed in the TESLA Technical Design
 Report~\cite{AguilarSaavedra:2001rg,Richard:2001qm}). Note that up to
 now there have not been any setups for a photon collider option for
 the modern linear collider concepts like ILC and CLIC. The string
 variable \ttt{\$circe2\_file} then allows to give the name of the file
 containing the actual beam spectrum; all files that ship with
 \whizard\ are stored in the directory \ttt{circe2/share/data}.
 
 More details about the subpackage \circetwo\ and the physics it
 covers, can be found in its own manual and the chapter
 Chap.~\ref{chap:hardint}.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Concatenation of several structure functions}
 \label{sec:concatenation}
 
 As has been shown already in Sec.~\ref{sec:epa} and
 Sec.~\ref{sec:ewa}, it is possible within \whizard\ to concatenate
 more than one structure function, irrespective of the fact, whether
 the structure functions are single-beam structure functions or pair
 spectra. One important thing is whether there is a phase-space mapping
 for these structure functions. Also, there are some combinations which
 do not make sense from the physics point of view, for example using
 lepton-collider ISR for protons, and then afterwards switching on
 PDFs. Such combinations will be vetoed by \whizard, and you will find
 an error message like (cf. also Sec.~\ref{sec:errors}):
 \begin{interaction}
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Beam structure: [....] not supported
 ******************************************************************************
 ******************************************************************************
 \end{interaction}
 
 Common examples for the concatenation of structure functions are
 linear collider applications, where beamstrahlung (macroscopic
 electromagnetic beam-beam interactions) and electron QED initial-state
 radiation are both switched on:
 \begin{code}
 beams = e1, E1 => circe1 => isr
 \end{code}
 Another possibility is the simulation of photon-induced backgrounds at
 ILC or CLIC, using beamstrahlung and equivalent photon approximation
 (EPA):
 \begin{code}
 beams = e1, E1 => circe1 => epa
 \end{code}
 or with beam events from a data file:
 \begin{code}
 beams = e1, E1 => beam_events => isr
 \end{code}
 
 In hadron collider physics, parton distribution functions (PDFs) are
 basically always switched on, while afterwards the user could specify
 to use the effective $W$ approximation (EWA) to simulate high-energy
 vector boson scattering:
 \begin{code}
 sqrts = 100 TeV
 beams = p, p => pdf_builtin => ewa
 \end{code}
 Note that this last case involves a flavor sum over the five active
 quark (and anti-quark) species $u$, $d$, $c$, $s$, $b$ in the proton,
 all of which act as radiators for the electroweak vector bosons in the
 EWA.
 
 This would be an example with three structure functions:
 \begin{code}
 beams = e1, E1 => circe1 => isr => epa
 \end{code}
 
 %%%%%%%%%%%%%%%
 
 \section{Polarization}
 \label{sec:polarization}
 
 %%%%%
 
 \subsection{Initial state polarization}
 \label{sec:initialpolarization}
 
 \whizard\ supports polarizing the inital state fully or partially by
 assigning a nontrivial density matrix in helicity space.
 Initial state polarization requires a beam setup and is initialized by
 means of the \ttt{beams\_pol\_density} statement\footnote{Note that
   the syntax for the specification of beam polarization has changed
   from version v2.1 to v2.2 and is incompatible between the two
   release series. The old syntax \ttt{beam\_polarization} with its
   different polarization constructors has been discarded in favor of a
   unified syntax.}:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 beams_pol_density = @([<spin entries>]), @([<spin entries>])
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The command \ttt{beams\_pol\_fraction} gives the degree of
 polarization of the two beams:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 beams_pol_fraction = <degree beam 1>, <degree beam 2>
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Both commands in the form written above apply to scattering processes,
 where the polarization of both beams must be specified. The
 \ttt{beams\_pol\_density} and \ttt{beams\_pol\_fraction} are possible
 with a single beam declaration if a decay process is considered, but
 only then.
 
 While the syntax for the command \ttt{beams\_pol\_fraction} is pretty
 obvious, the syntax for the actual specification of the beam
 polarization is more intricate. We start with the polarization
 fraction: for each beam there is a real number between zero
 (unpolarized) and one (complete polarization) that can be specified
 either as a floating point number like \ttt{0.4} or with a percentage:
 \ttt{40 \%}. Note that the actual arithmetics is sometimes
 counterintuitive: 80 \% left-handed electron polarization means that
 80 \% of the electron beam are polarized, 20 \% are unpolarized,
 i.e. 20 \% have half left- and half right-handed polarization
 each. Hence, 90 \% of the electron beam is left-handed, 10 \% is
 right-handed.
 
 How does the specification of the polarization work? If there are no
 entries at all in the polarization constructor, \ttt{@()}, the beam is
 unpolarized, and the spin density matrix is proportional to the
 unit/identity matrix. Placing entries into the \ttt{@()} constructor
 follows the concept of sparse matrices, i.e. the entries that have
 been specified will be present, while the rest remains zero. Single
 numbers do specify entries for that particular helicity on the main
 diagonal of the spin density matrix, e.g. for an electron \ttt{@(-1)}
 means (100\%) left-handed polarization. Different entries are
 separated by commas: \ttt{@(1,-1)} sets the two diagonal entries at
 positions $(1,1)$ and $(-1,-1)$ in the density matrix both equal to
 one. Two remarks are in order
 already here. First, note that you do not have to worry about the
 correct normalization of the spin density matrix, \whizard\ is taking
 care of this automatically. Second, in the screen output for the beam
 data, only those entries of the spin density matrix that have been
 specified by the user, will be displayed. If a
 \ttt{beams\_pol\_fraction} statement appears, other components will be
 non-zero, but might not be shown. E.g. ILC-like, 80 \% polarization of
 the electrons, 30 \% positron polarization will be specified like this
 for left-handed electrons and right-handed positrons:
 \begin{code}
 beams = e1, E1
 beams_pol_density = @(-1), @(+1)
 beams_pol_fraction = 80%, 30%
 \end{code}
 The screen output will be like this:
 \begin{code}
 | ------------------------------------------------------------------------
 | Beam structure: e-, e+
 |   polarization (beam 1):
 |     @(-1: -1: ( 1.000000000000E+00, 0.000000000000E+00))
 |   polarization (beam 2):
 |     @(+1: +1: ( 1.000000000000E+00, 0.000000000000E+00))
 |   polarization degree = 0.8000000, 0.3000000
 | Beam data (collision):
 |   e-   (mass = 0.0000000E+00 GeV)  polarized
 |   e+   (mass = 0.0000000E+00 GeV)  polarized
 \end{code}
 But because of the fraction of unpolarized electrons and positrons,
 the spin density matrices for electrons and positrons are:
 \[
 \rho(e^-) = \diag \left ( 0.10, 0.90 \right) \qquad
 \rho(e^+) = \diag \left ( 0.65, 0.35 \right) \quad ,
 \]
 respectively. So, in general, only the entries due to the polarized
 fraction will be displayed on screen. We will come back to more
 examples below.
 
 Again, the setting of a single entry, e.g. \ttt{@($\pm m$)}, which
 always sets the diagonal component $(\pm m, \pm m)$ of the spin
 density matrix equal to one. Here $m$ can have the following values
 for the different spins (in parentheses are entries that exist only
 for massive particles):
 
 \vspace{1mm}
 
 \begin{center}
 \begin{tabular}{|l|l|l|}\hline
   Spin $j$ & Particle type & possible $m$ values \\\hline
   0   & Scalar boson           & 0 \\
   1/2 & Spinor                 & +1, -1 \\
   1   & (Massive) Vector boson & +1, (0), -1 \\
   3/2 & (Massive) Vectorspinor & +2, (+1), (-1), -2 \\
   2   & (Massive) Tensor       & +2, (+1), (0), (-1), -2
   \\\hline
 \end{tabular}
 \end{center}
 
 \vspace{1mm}
 
 Off-diagonal entries that are equal to one (up to the normalization)
 of the spin-density matrix can be specified simply by the position,
 namely: \ttt{@($m$:$m'$, $m''$)}. This would result in a spin density
 matrix with diagonal entry $1$ for the position $(m'', m'')$, and an entry
 of $1$ for the off-diagonal position $(m,m')$.
 
 Furthermore, entries in the density matrix different from $1$ with a
 numerical value \ttt{{\em <val>}} can be
 specified, separated by another colon: \ttt{@($m$:$m'$:{\em
 <val>})}. Here, it does not matter whether $m$ and $m'$ are different
 or not. For $m = m'$ also diagonal spin density matrix entries
 different from one can be specified. Note that because spin density
 matrices have to be Hermitian, only the entry $(m,m')$ has to be set,
 while the complex conjugate entry at the transposed position $(m',m)$
 is set automatically by \whizard.
 
 We will give some general density
 matrices now, and after that a few more definite examples. In the
 general setups below, we always give the expression for the spin
 density matrix only for one single beam.
 %
 {
 
 \newcommand{\cssparse}[4]{%
 \begin{pmatrix}
   #1     & 0      & \cdots & \cdots & #3     \\
   0      & 0      & \ddots &        & 0      \\
   \vdots & \ddots & \ddots & \ddots & \vdots \\
   0      &        & \ddots & 0      & 0      \\
   #4     & \cdots & \cdots & 0      & #2
 \end{pmatrix}%
 }
 %
 
 \begin{itemize}
 \item {\bf Unpolarized:}
   \begin{center}
     \begin{footnotesize}
     \ttt{beams\_pol\_density = @()}
     \end{footnotesize}
   \end{center}
 % \newline
 This has the same effect as not specifying any
 polarization at all and is the only constructor available for scalars and
 fermions declared as left- or right-handed (like the neutrino). Density matrix:
 \[ \rho = \frac{1}{|m|}\mathbb{I} \]
 ($|m|$: particle multiplicity which is 2 for massless, $2j + 1$ for massive particles).
 %
 \item {\bf Circular polarization:}
   \begin{center}
     \begin{footnotesize}
     \ttt{beams\_pol\_density = @($\pm j$) \qquad beams\_pol\_fraction
       = $f$}
     \end{footnotesize}
   \end{center}
 A fraction $f$ (parameter range $f \in \left[0\;;\;1\right]$) of
 the particles are in the maximum / minimum helicity eigenstate $\pm
 j$, the remainder is unpolarized. For spin $\frac{1}{2}$ and massless
 particles of spin $>0$, only the maximal / minimal entries of the
 density matrix are populated, and the density matrix looks like this:
 \[ \rho = \diag\left(\frac{1\pm f}{2}\;,\;0\;,\;\dots\;,\;0\;,
 \frac{1\mp f}{2}\right) \]
 %
 \item {\bf Longitudinal polarization (massive):}
   \begin{center}
     \begin{footnotesize}
     \ttt{beams\_pol\_density = @(0) \qquad beams\_pol\_fraction = $f$}
     \end{footnotesize}
   \end{center}
 We consider massive particles with maximal spin component $j$, a
 fraction $f$ of which having longitudinal polarization, the remainder
 is unpolarized. Longitudinal polarization is (obviously) only
 available for massive bosons of spin $>0$. Again, the parameter range
 for the fraction is: $f \in \left[0\;;\;1\right]$. The density matrix
 has the form:
 \[ \rho = \diag\left(\frac{1-f}{|m|}\;,\;\dots\;,\;\frac{1-f}{|m|}\;,\;
 \frac{1+f \left(|m| - 1\right)}{|m|}\;,\;\frac{1-f}{|m|}\;,
 \;\dots\;,\;\frac{1-f}{|m|}\right)
 \]
 ($|m| = 2j+1 $: particle multiplicity)
 %
 \item {\bf Transverse polarization (along an axis):}
   \begin{center}
     \begin{footnotesize}
     \ttt{beams\_pol\_density = @(j, -j, j:-j:exp(-I*phi)) \qquad
       beams\_pol\_fraction = $f$}
     \end{footnotesize}
   \end{center}
 This so called transverse polarization is a polarization along an
 arbitrary direction in the $x-y$ plane, with $\phi=0$ being the positive
 $x$ direction and $\phi=90^\circ$ the positive $y$ direction. Note that
 the value of \ttt{phi} has either to be set inside the beam
 polarization expression explicitly or by a statement \ttt{real phi =
   {\em val} degree} before. A fraction $f$ of the particles are
 polarized, the remainder is unpolarized. Note that, although
 this yields a valid density matrix for all particles with multiplicity
 $>1$ (in which the only the highest and lowest helicity states are
 populated), it is meaningful only for spin $\frac{1}{2}$ particles and
 massless bosons of spin $>0$. The range of the parameters are:
 $f \in \left[0\;;\;1\right]$ and $\phi \in \mathbb{R}$. This yields a
 density matrix:
 \[ \rho =
 \cssparse{1}{1}
    {\frac{f}{2}\,e^{-i\phi}} {\frac{f}{2}\,e^{i\phi}} \]
 (for antiparticles, the matrix is conjugated).
 %
 \item {\bf Polarization along arbitrary axis $\left(\theta, \phi\right)$:}
   \begin{center}
     \begin{footnotesize}
     \ttt{beams\_pol\_density = @(j:j:1-cos(theta),
       j:-j:sin(theta)*exp(-I*phi), -j:-j:1+cos(theta))} \qquad\quad\qquad
     \ttt{beams\_pol\_fraction = $f$}
     \end{footnotesize}
   \end{center}
 This example describes polarization along an arbitrary axis in polar
 coordinates (polar axis in positive $z$ direction, polar angle
 $\theta$, azimuthal angle $\phi$). A fraction $f$ of the particles are
 polarized, the remainder is unpolarized. Note that, although axis
 polarization defines a valid density matrix for all particles with
 multiplicity $>1$, it is meaningful only for particles with spin
 $\frac{1}{2}$. Valid ranges for the parameters are $f \in
 \left[0\;;\;1\right]$, $\theta \in \mathbb{R}$, $\phi \in
 \mathbb{R}$. The density matrix then has the form:
 \[ \rho = \frac{1}{2}\cdot
 \cssparse{1 - f\cos\theta}{1 + f\cos\theta}
    {f\sin\theta\, e^{-i\phi}}{f\sin\theta\, e^{i\phi}}
 \]
 %
 \item {\bf Diagonal density matrix:}
   \begin{center}
     \begin{footnotesize}
     \ttt{beams\_pol\_density = @(j:j:$h_j$, j-1:j-1:$h_{j-1}$,
       $\ldots$, -j:-j:$h_{-j}$)}
     \end{footnotesize}
   \end{center}
 This defines an arbitrary diagonal density matrix with entries
 $\rho_{j,j}\,,\,\dots\,,\,\rho_{-j,-j}$.
 %
 \item {\bf Arbitrary density matrix:}
   \begin{center}
     \begin{footnotesize}
     \ttt{beams\_pol\_density = @($\{m:m':x_{m,m'}\}$)}:
     \end{footnotesize}
   \end{center}
 Here, \ttt{$\{m:m':x_{m,m'}\}$} denotes a selection of entries at
 various positions somewhere in the spin density matrix. \whizard\
 will check whether this is a valid spin density matrix, but it does
 e.g. not have to correspond to a pure state.
 %
 \end{itemize}
 }
 %
 
 The beam polarization statements can be used both globally directly
 with the \ttt{beams} specification, or locally inside the
 \ttt{integrate} or \ttt{simulate} command. Some more specific examples
 are in order to show how initial state polarization works:
 %
 \begin{itemize}
 \item
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 beams = A, A
 beams_pol_density = @(+1),  @(1, -1, 1:-1:-I)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This declares the initial state to be composed of two incoming
 photons, where the first photon is right-handed, and the second photon
 has transverse polarization in $y$ direction.
 %
 \item
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 beams = A, A
 beams_pol_density = @(+1),  @(1, -1, 1:-1:-1)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Same as before, but this time the second photon has transverse
 polarization in $x$ direction.
 
 %
 \item
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 beams = "W+"
 beams_pol\_density = @(0)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This example sets up the decay of a longitudinal vector boson.
 %
 \item
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 beams = E1, e1
 scan int hel_ep = (-1, 1) {
    scan int hel_em = (-1, 1) {
       beams_pol_density = @(hel_ep), @(hel_em)
       integrate (eeww)
    }
 }
 integrate (eeww)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This example loops over the different positron and electron helicity
 combinations and calculates the respective integrals. The
 \ttt{beams\_pol\_density} statement is local to the scan loop(s) and,
 therefore, the last \ttt{integrate} calculates the unpolarized
 integral.
 \end{itemize}
 %
 
 Although beam polarization should be straightforward to use, some pitfalls exist
 for the unwary:
 \begin{itemize}
 \item Once \ttt{beams\_pol\_density} is set globally, it persists and
 is applied every time \ttt{beams} is executed (unless it is reset). In
 particular, this means that code like
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 process wwaa = Wp, Wm => A, A
 process zee = Z => e1, E1
 
 sqrts = 200 GeV
 beams_pol_density = @(1, -1, 1:-1:-1), @()
 beams = Wp, Wm
 integrate (wwaa)
 beams = Z
 integrate (zee)
 beams_pol_density = @(0)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 will throw an error, because \whizard\ complains that the spin density
 matrix has the wrong dimensionality for the second (the decay) process.
 This kind of trap can be avoided be using \ttt{beams\_pol\_density}
 only locally in \ttt{integrate} or \ttt{simulate} statements.
 %
 \item On-the-fly integrations executed by \ttt{simulate}
 use the beam
 setup found at the point of execution. This implies that any polarization
 settings you have previously done affect the result of the integration.
 %
 \item The \ttt{unstable} command also requires integrals of the selected decay
   processes, and will compute them on-the-fly if they are unavailable.  Here,
   a polarized integral is not meaningful at all.  Therefore, this command
   ignores the current \ttt{beam} setting and issues a warning if a previous
   polarized integral is available; this will be discarded.
 \end{itemize}
 
 
 \subsection{Final state polarization}
 
 Final state polarization is available in \whizard\ in the sense that the
 polarization of real final state particles can be retained when generating
 simulated
 events. In order for the polarization of a particle to be retained, it must be
 declared as polarized via the \ttt{polarized} statement
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 polarized particle [, particle, ...]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The effect of \ttt{polarized} can be reversed with the \ttt{unpolarized}
 statement which has the same syntax. For example,
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 polarized "W+", "W-", Z
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 will cause the polarization of all final state $W$ and $Z$ bosons to be
 retained, while
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 unpolarized "W+", "W-", Z
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 will reverse the effect and cause the polarization to be summed over again. Note
 that \ttt{polarized} and \ttt{unpolarized} are global statements which cannot be
 used locally as command arguments and if you use them e.g. in a loop, the
 effects will persist beyond the loop body. Also, a particle cannot be
 \ttt{polarized} and \ttt{unstable} at the same time (this restriction
 might be loosened in future versions of \whizard).
 
 After toggling the polarization flag, the generation of polarized events can be
 requested by using the \ttt{?polarized\_events} option of the \ttt{simulate}
 command, e.g.
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 simulate (eeww) { ?polarized_events = true }
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 When \ttt{simulate} is run in this mode, helicity information for final state
 particles that have been toggled as \ttt{polarized} is written to the event
 file(s) (provided that polarization is supported by the selected event file
 format(s) ) and can also be accessed in the analysis by means of the \ttt{Hel}
 observable. For example, an analysis definition like
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 analysis =
   if (all Hel == -1 ["W+"] and all Hel == -1 ["W-"] ) then
     record cta_nn (eval cos (Theta) ["W+"]) endif;
   if (all Hel == -1 ["W+"] and all Hel ==  0 ["W-"] )
     then record cta_nl (eval cos (Theta) ["W+"]) endif
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 can be used to histogram the angular distribution for the production of
 polarized $W$ pairs (obviously, the example would have to be extended
 to cover all possible helicity combinations). Note, however, that
 helicity information is not available in the integration step;
 therefore, it is not possible to use \ttt{Hel} as a cut observable.
 
 While final state polarization is straightforward to use, there is a caveat when
 used in combination with flavor products. If a particle in a flavor product is
 defined as \ttt{polarized}, then all particles ``originating'' from the product will
 act as if they had been declared as \ttt{polarized} --- their polarization will
 be recorded in the generated events. E.g., the example
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 process test = u:d, ubar:dbar => d:u, dbar:ubar, u, ubar
 
 ! insert compilation, cuts and integration here
 
 polarized d, dbar
 simulate (test) {?polarized_events = true}
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 will generate events including helicity information for all final state $d$ and
 $\overline{d}$ quarks, but only for part of the final state $u$ and $\overline{u}$
 quarks. In this case, if you had wanted to keep the helicity information also
 for all $u$ and $\overline{u}$, you would have had to explicitely include them
 into the \ttt{polarized} statement.
 
 
 \section{Cross sections}
 
 Integrating matrix elements over phase space is the core of \whizard's
 activities.  For any process where we want the cross section, distributions,
 or event samples, the cross section has to be determined first.  This is done
 by a doubly adaptive multi-channel Monte-Carlo integration.  The integration,
 in turn, requires a \emph{phase-space setup}, i.e., a collection of
 phase-space \emph{channels}, which are mappings of the unit hypercube onto the
 complete space of multi-particle kinematics.  This phase-space information is
 encoded in the file \emph{xxx}\ttt{.phs}, where \emph{xxx} is the process tag.
 \whizard\ generates the phase-space file on the fly and can reuse it in later
 integrations.
 
 For each phase-space channel, the unit hypercube is binned in each dimension.
 The bin boundaries are allowed to move during a sequence of iterations, each
 with a fixed number of sampled phase-space points, so they adapt to the actual
 phase-space density as far as possible.  In addition to this \emph{intrinsic}
 adaptation, the relative channel weights are also allowed to vary.
 
 All these steps are done automatically when the \ttt{integrate} command is
 executed.  At the end of the iterative adaptation procedure, the program has
 obtained an estimate for the integral of the matrix element over phase space,
 together with an error estimate, and a set of integration \emph{grids} which
 contains all information on channel weights and bin boundaries.  This
 information is stored in a file \emph{xxx}\ttt{.vg}, where \emph{xxx} is the
 process tag, and is used for event generation by the \ttt{simulate}
 command.
 
 
 \subsection{Integration}
 \label{sec:integrate}
 
 Since everything can be handled automatically using default parameters, it
 often suffices to write the command
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   integrate (proc1)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 for integrating the process with name tag \ttt{proc1}, and similarly
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   integrate (proc1, proc2, proc3)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 for integrating several processes consecutively.  Options to the integrate
 command are specified, if not globally, by a local option string
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   integrate (proc1, proc2, proc3) { mH = 200 GeV }
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 (It is possible to place a \ttt{beams} statement inside the option string, if
 desired.)
 
 If the process is configured but not compiled, compilation will be done
 automatically.   If it is not available at all, integration will fail.
 
 The integration method can be specified by the string variable
 \begin{quote}
 \begin{footnotesize}
   \ttt{\$integration\_method = "{\em <method>}"}
 \end{footnotesize}
 \end{quote} %$
 The default method is called \ttt{"vamp"} and uses the \vamp\
 algorithm and code. (At the moment, there is only a single simplistic
 alternative, using the midpoint rule or rectangle method for
 integration, \ttt{"midpoint"}. This is mainly for testing purposes. In
 future versions of \whizard, more methods like e.g. Gauss integration
 will be made available). \vamp, however, is clearly the main
 integration method. It is done in several \emph{passes} (usually two),
 and each pass consists of several \emph{iterations}.  An iteration
 consists of a definite number of \emph{calls} to the matrix-element
 function.
 
 For each iteration, \whizard\ computes an estimate of the integral and an
 estimate of the error, based on the binned sums of matrix element values and
 squares.  It also computes an estimate of the rejection efficiency for
 generating unweighted events, i.e., the ratio of the average sampling function
 value over the maximum value of this function.
 
 After each iteration, both the integration grids (the binnings) and the
 relative weights of the integration channels can be adapted to
 minimize the variance estimate of the integral.  After each pass of several
 iterations, \whizard\ computes an average of the iterations within the pass,
 the corresponding error estimate, and a $\chi^2$ value.  The integral, error,
 efficiency and $\chi^2$ value computed for the most recent integration pass,
 together with the most recent integration grid, are used for any subsequent
 calculation that involves this process, in particular for event generation.
 
 In the default setup, during the first pass(es) both grid binnings and channel
 weights are adapted.  In the final (usually second) pass, only binnings are
 further adapted.  Roughly speaking, the final pass is the actual calculation,
 while the previous pass(es) are used for ``warming up'' the integration grids,
 without using the numerical results. Below, in the section about the
 specification of the iterations, Sec.~\ref{sec:iterations}, we will
 explain how it is possible to change the behavior of adapting grids
 and weights.
 
 Here is an example of the integration output, which illustrates these
 properties.  The \sindarin\ script describes the process $e^+e^-\to q\bar q
 q\bar q$ with $q$ being any light quark, i.e., $W^+W^-$ and $ZZ$ production
 and hadronic decay together will any irreducible background.  We cut on $p_T$
 and energy of jets, and on the invariant mass of jet pairs.  Here is the
 script:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 alias q = d:u:s:c
 alias Q = D:U:S:C
 process proc_4f = e1, E1 => q, Q, q, Q
 
 ms = 0  mc = 0
 sqrts = 500 GeV
 cuts = all (Pt > 10 GeV and E > 10 GeV) [q:Q]
    and all M > 10 GeV [q:Q, q:Q]
 
 integrate (proc_4f)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 After the run is finished, the integration output looks like
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 | Process library 'default_lib': loading
 | Process library 'default_lib': ... success.
 | Integrate: compilation done
 | RNG: Initializing TAO random-number generator
 | RNG: Setting seed for random-number generator to 12511
 | Initializing integration for process proc_4f:
 | ------------------------------------------------------------------------
 | Process [scattering]: 'proc_4f'
 |   Library name  = 'default_lib'
 |   Process index = 1
 |   Process components:
 |     1: 'proc_4f_i1':   e-, e+ => d:u:s:c, dbar:ubar:sbar:cbar,
 |                                  d:u:s:c, dbar:ubar:sbar:cbar [omega]
 | ------------------------------------------------------------------------
 | Beam structure: [any particles]
 | Beam data (collision):
 |   e-  (mass = 5.1099700E-04 GeV)
 |   e+  (mass = 5.1099700E-04 GeV)
 |   sqrts = 5.000000000000E+02 GeV
 | Phase space: generating configuration ...
 | Phase space: ... success.
 | Phase space: writing configuration file 'proc_4f_i1.phs'
 | Phase space: 123 channels, 8 dimensions
 | Phase space: found 123 channels, collected in 15 groves.
 | Phase space: Using 195 equivalences between channels.
 | Phase space: wood
 | Applying user-defined cuts.
 | OpenMP: Using 8 threads
 | Starting integration for process 'proc_4f'
 | Integrate: iterations not specified, using default
 | Integrate: iterations = 10:10000:"gw", 5:20000:""
 | Integrator: 15 chains, 123 channels, 8 dimensions
 | Integrator: Using VAMP channel equivalences
 | Integrator: 10000 initial calls, 20 bins, stratified = T
 | Integrator: VAMP
 |=============================================================================|
 | It      Calls  Integral[fb]  Error[fb]   Err[%]    Acc  Eff[%]   Chi2 N[It] |
 |=============================================================================|
    1       9963  2.3797857E+03  3.37E+02   14.15   14.13*   4.02
    2       9887  2.8307603E+03  9.58E+01    3.39    3.37*   4.31
    3       9815  3.0132091E+03  5.10E+01    1.69    1.68*   8.37
    4       9754  2.9314937E+03  3.64E+01    1.24    1.23*  10.65
    5       9704  2.9088284E+03  3.40E+01    1.17    1.15*  12.99
    6       9639  2.9725788E+03  3.53E+01    1.19    1.17   15.34
    7       9583  2.9812484E+03  3.10E+01    1.04    1.02*  17.97
    8       9521  2.9295139E+03  2.88E+01    0.98    0.96*  22.27
    9       9435  2.9749262E+03  2.94E+01    0.99    0.96   20.25
   10       9376  2.9563369E+03  3.01E+01    1.02    0.99   21.10
 |-----------------------------------------------------------------------------|
   10      96677  2.9525019E+03  1.16E+01    0.39    1.22   21.10    1.15  10
 |-----------------------------------------------------------------------------|
   11      19945  2.9599072E+03  2.13E+01    0.72    1.02   15.03
   12      19945  2.9367733E+03  1.99E+01    0.68    0.96*  12.68
   13      19945  2.9487747E+03  2.03E+01    0.69    0.97   11.63
   14      19945  2.9777794E+03  2.03E+01    0.68    0.96*  11.19
   15      19945  2.9246612E+03  1.95E+01    0.67    0.94*  10.34
 |-----------------------------------------------------------------------------|
   15      99725  2.9488622E+03  9.04E+00    0.31    0.97   10.34    1.05   5
 |=============================================================================|
 | Time estimate for generating 10000 events: 0d:00h:00m:51s
 | Creating integration history display proc_4f-history.ps and proc_4f-history.pdf
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Each row shows the index of a single iteration, the number of matrix element
 calls for that iteration, and the integral and error estimate.  Note
 that the number of calls displayed are the real calls to the matrix
 elements after all cuts and possible rejections. The error
 should be viewed as the $1\sigma$ uncertainty, computed on a statistical
 \begin{figure}
   \centering
   \includegraphics[width=.56\textwidth]{proc_4f-history}
   \caption{\label{fig:inthistory} Graphical output of the convergence
     of the adaptation during the integration of a \whizard\ process.}
 \end{figure}
 basis.  The next two columns display the error in percent, and the
 \emph{accuracy} which is the same error normalized by $\sqrt{n_{\rm calls}}$.
 The accuracy value has the property that it is independent of $n_{\rm calls}$,
 it describes the quality of adaptation of the current grids.  Good-quality
 grids have a number of order one, the smaller the better.  The next column is
 the estimate for the rejection efficiency in percent.  Here, the value should
 be as high as possible, with $100\,\%$ being the possible maximum.
 
 In the example, the grids are adapted over ten iterations, after which the
 accuracy and efficiency have saturated at about $1.0$ and $10\,\%$,
 respectively.  The asterisk in the accuracy column marks those iterations
 where an improvement over the previous iteration is seen.  The average over
 these iterations exhibits an accuracy of $1.22$, corresponding to $0.39\,\%$
 error, and a $\chi^2$ value of $1.15$, which is just right:
 apparently, the phase-space for this process and set of cuts is
 well-behaved.  The subsequent five iterations are used for obtaining
 the final integral, which has an accuracy below one (error $0.3\,\%$),
 while the efficiency settles at about
 $10\,\%$.  In this example, the final $\chi^2$ value happens to be quite
 small, i.e., the individual results are closer together than the error
 estimates would suggest.  One should nevertheless not scale down the error,
 but rather scale it up if the $\chi^2$ result happens to be much larger than
 unity: this often indicates sub-optimally adapted grids, which insufficiently
 map some corner of phase space.
 
 One should note that all values are subject to statistical fluctuations, since
 the number of calls within each iterations is finite.  Typically, fluctuations
 in the efficiency estimate are considerably larger than fluctuations in the
 error/accuracy estimate.  Two subsequent runs of the same script should yield
 statistically independent results which may differ in all quantities, within
 the error estimates, since the seed of the random-number generator will differ
 by default.
 
 It is possible to get exactly reproducible results by setting the
 random-number seed explicitly, e.g.,
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   seed = 12345
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 at any point in the \sindarin\ script.  \ttt{seed} is a predefined intrinsic
 variable.  The value can be any 32bit integer.  Two runs with different seeds
 can be safely taken as statistically independent. In the example
 above, no seed has been set, and the seed has therefore been
 determined internally by \whizard\ from the system clock.
 
 The concluding line with the time estimate applies to a subsequent simulation
 step with unweighted events, which is not actually requested in the current
 example.  It is based on the timing and efficiency estimate of the most recent
 iteration.
 
 As a default, a graphical output of the integration history will be
 produced (if both \LaTeX\ and \metapost\ have been available during
 configuration). Fig.~\ref{fig:inthistory} shows how this looks like,
 and demonstrates how a proper convergence of the integral during the
 adaptation looks like. The generation of these graphical history files
 can be switched off using the command \ttt{?vis\_history = false}.
 
 %%%%%
 
 \subsection{Integration run IDs}
 
 A single \sindarin\ script may contain multiple calls to the
 \ttt{integrate} command with different parameters.  By default,
 files generated for the same process in a subsequent integration will
 overwrite the previous ones.  This is undesirable when the script is
 re-run: all results that have been overwritten have to be recreated.
 
 To avoid this, the user may identify a specific run by a string-valued
 ID, e.g.
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   integrate (foo) { $run_id = "first" }
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This ID will become part of the file name for all files that are
 created specifically for this run.  Often it is useful to create a run
 ID from a numerical value using \ttt{sprintf}, e.g., in this scan:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   scan real mh = (100 => 200 /+ 10) {
     $run_id = sprintf "%e" (mh)
     integrate (h_production)
   }
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 With unique run IDs, a subsequent run of the same \sindarin\ script
 will be able to reuse all previous results, even if there is more than
 a single integration per process.
 
 
 
 
 \subsection{Controlling iterations}
 \label{sec:iterations}
 
 \whizard\ has some predefined numbers of iterations and calls for the first
 and second integration pass, respectively, which depend on the number of
 initial and final-state particles.  They are guesses for values that yield
 good-quality grids and error values in standard situations, where no
 exceptionally strong peaks or loose cuts are present in the integrand.
 Actually, the large number of warmup iterations in the previous example
 indicates some safety margin in that respect.
 
 It is possible, and often advisable, to adjust the iteration and call numbers
 to the particular situation.  One may reduce the default numbers to short-cut
 the integration, if either less accuracy is needed, or CPU time is to be
 saved.  Otherwise, if convergence is bad, the number of iterations or calls
 might be increased.
 
 To set iterations manually, there is the \ttt{iterations} command:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   iterations = 5:50000, 3:100000
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This is a comma-separated list.  Each pair of values corresponds to an
 integration pass.  The value before the colon is the number of iterations for
 this pass, the other number is the number of calls per iteration.
 
 While the default number of passes is two (one for warmup, one for the final
 result), you may specify a single pass
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   iterations = 5:100000
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 where the relative channel weights will \emph{not} be adjusted (because this
 is the final pass).  This is appropriate for well-behaved integrands where
 weight adaptation is not necessary.
 
 You can also define more than two passes.  That might be useful when reusing a
 previous grid file with insufficient quality: specify the previous passes
 as-is, so the previous results will be read in, and then a new pass for
 further adaptation.
 
 In the final pass, the default behavior is to not adapt grids and
 weights anymore. Otherwise, different iterations would be correlated,
 and a final reliable error estimate would not be possible. For all but
 the final passes, the user can decide whether to adapt grids and
 weights by attaching a string specifier to the number of iterations:
 \ttt{"g"} does adapt grids, but not weights, \ttt{"w"} the other way
 round. \ttt{"gw"} or \ttt{"wg"} does adapt both. By the setting
 \ttt{""}, all adaptations are switched off. An example looks like
 this:
 \begin{code}
   iterations = 2:10000:"gw", 3:5000
 \end{code}
 
 Since it is often not known beforehand how many iterations the grid
 adaptation will need, it is generally a good idea to give the first
 pass a large number of iterations.  However, in many cases these turn
 out to be not necessary.  To shortcut iterations, you can set any of
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 accuracy_goal
 error_goal
 relative_error_goal
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 to a positive value.  If this is done, \whizard\ will skip warmup
 iterations once all of the specified goals are reached by the current
 iteration.  The final iterations (without weight adaptation) are
 always performed.
 
 
 \subsection{Phase space}
 
 Before \ttt{integrate} can start its work, it must have a phase-space
 configuration for the process at hand.  The method for the phase-space
 parameterization is determined by the string variable
 \ttt{\$phs\_method}. At the moment there are only two options,
 \ttt{"single"}, for testing purposes, that is mainly used internally,
 and \whizard's traditional method, \ttt{"wood"}. This parameterization
 is particularly adapted and fine-tuned for electroweak processes and
 might not be the ideal for for pure jet cross sections. In future
 versions of \whizard, more options for phase-space parameterizations
 will be made available, e.g. the \ttt{RAMBO} algorithm and its massive
 cousin, and phase-space parameterizations that take care of the
 dipole-like emission structure in collinear QCD (or QED) splittings.
 For the standard method, the phase-space parameterization is laid out
 in an ASCII file \ttt{\textit{<process-name>\_}i\textit{<comp>}.phs}.
 Here, \ttt{{\em <process-name>}} is the process name chosen by the
 user while \ttt{{\em <comp>}} is the number of the process component
 of the corresponding process. This immediately shows that different
 components of processes are getting different phase space setups. This
 is necessary for inclusive processes, e.g. the sum of $pp \to Z + nj$
 and $pp \to W + nj$, or in future versions of \whizard\ for NLO
 processes, where one component is the interference between the virtual
 and the Born matrix element, and another one is the subtraction terms.
 Normally, you do not have to deal with this file, since \whizard\ will
 generate one automatically if it does not find one. (\whizard\ is
 careful to check for consistency of process definition and parameters
 before using an existing file.)
 
 Experts might find it useful to generate a phase-space file and inspect and/or
 modify it before proceeding further.  To this end, there is the parameter
 \verb|?phs_only|.  If you set this \ttt{true}, \whizard\ skips the actual
 integration after the phase-space file has been generated.  There is also a
 parameter \verb|?vis_channels| which can be set independently; if this is
 \ttt{true}, \whizard\ will generate a graphical visualization of the
 phase-space parameterizations encoded in the phase-space file. This
 file has to be taken with a grain of salt because phase space channels
 are represented by sample Feynman diagrams for the corresponding
 channel. This does however {\em not} mean that in the matrix element
 other Feynman diagrams are missing (the default matrix element method,
 \oMega, is not using Feynman-diagrammatic amplitudes at all).
 
 Things might go wrong with the default phase-space generation, or manual
 intervention might be necessary to improve later performance.  There are a few
 parameters that control the algorithm of phase-space generation.  To
 understand their meaning, you should realize that phase-space
 parameterizations are modeled after (dominant) Feynman graphs for the current
 process.
 
 \subsubsection{The main phase space setup {\em wood}}
 
 For the main phase-space parameterization of \whizard, which is called
 \ttt{"wood"}, there are many different parameters and flags that allow
 to tune and customize the phase-space setup for every certain process:
 
 The parameter \verb|phs_off_shell| controls the number of off-shell lines in
 those graphs, not counting $s$-channel resonances and logarithmically enhanced
 $s$- and $t$-channel lines.  The default value is $2$.  Setting it to zero
 will drop everything that is not resonant or logarithmically enhanced.
 Increasing it will include more subdominant graphs.  (\whizard\ increases the
 value automatically if the default value does not work.)
 
 There is a similar parameter \verb|phs_t_channel| which controls
 multiperipheral graphs in the parameterizations.  The default value is $6$, so
 graphs with up to $6$ $t/u$-channel lines are considered.  In particular
 cases, such as $e^+e^-\to n\gamma$, all graphs are multiperipheral, and for
 $n>7$ \whizard\ would find no parameterizations in the default setup.
 Increasing the value of \verb|phs_t_channel| solves this problem.  (This is
 presently not done automatically.)
 
 There are two numerical parameters that describe whether particles are treated
 like massless particles in particular situations.  The value of
 \verb|phs_threshold_s| has the default value $50\;\GeV$.  Hence, $W$ and $Z$
 are considered massive, while $b$ quarks are considered massless.  This
 categorization is used for deciding whether radiation of $b$ quarks can lead
 to (nearly) singular behavior, i.e., logarithmic enhancement, in the infrared
 and collinear regions.  If yes, logarithmic mappings are applied to phase
 space.  Analogously, \verb|phs_threshold_t| decides about potential
 $t$-channel singularities.  Here, the default value is $100\;\GeV$, so
 amplitudes with $W$ and $Z$ in the $t$-channel are considered as
 logarithmically enhanced. For a high-energy hadron collider of 40 or
 100 TeV energy, also $W$ and $Z$ in $s$-channel like situations might
 be necessary to be considered massless.
 
 Such logarithmic mappings need a dimensionful scale as parameter.  There are
 three such scales, all with default value $10\;\GeV$: \verb|phs_e_scale|
 (energy), \verb|phs_m_scale| (invariant mass), and \verb|phs_q_scale|
 (momentum transfer).  If cuts and/or masses are such that energies, invariant
 masses of particle pairs, and momentum transfer values below $10\;\GeV$ are
 excluded or suppressed, the values can be kept.  In special cases they should
 be changed: for instance, if you want to describe $\gamma^*\to\mu^+\mu^-$
 splitting well down to the muon mass, no cuts, you may set
 \verb|phs_m_scale = mmu|.  The convergence of the Monte-Carlo integration
 result will be considerably faster.
 
 There are more flags. These and more details about the phase space
 parameterization will be described in Sec.~\ref{sec:wood}.
 
 
 \subsection{Cuts}
 
 \whizard~2 does not apply default cuts to the integrand.  Therefore, processes
 with massless particles in the initial, intermediate, or final states may not
 have a finite cross section.  This fact will manifest itself in an integration
 that does not converge, or is unstable, or does not yield a reasonable error
 or reweighting efficiency even for very large numbers of iterations or calls
 per iterations.  When doing any calculation, you should verify first that the
 result that you are going to compute is finite on physical grounds.  If not,
 you have to apply cuts that make it finite.
 
 A set of cuts is defined by the \ttt{cuts} statement.  Here is an example
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 cuts = all Pt > 20 GeV [colored]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This implies that events are kept only (for integration and simulation) if the
 transverse momenta of all colored particles are above $20\;\GeV$.
 
 Technically, \ttt{cuts} is a special object, which is unique within a given
 scope, and is defined by the logical expression on the right-hand side of the
 assignment.  It may be defined in global scope, so it is applied to all
 subsequent processes.  It may be redefined by another \ttt{cuts} statement.
 This overrides the first cuts setting: the \ttt{cuts} statement is not
 cumulative.  Multiple cuts should be specified by the logical operators of
 \sindarin, for instance
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 cuts = all Pt > 20 GeV [colored]
   and all E > 5 GeV [photon]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Cuts may also be defined local to an \ttt{integrate} command, i.e., in the
 options in braces.   They will apply only to the processes being integrated,
 overriding any global cuts.
 
 The right-hand side expression in the \ttt{cuts} statement is evaluated at the
 point where it is used by an \ttt{integrate} command (which could be an
 implicit one called by \ttt{simulate}).  Hence, if the logical expression
 contains parameters, such as
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 mH = 120 GeV
 cuts = all M > mH [b, bbar]
 mH = 150 GeV
 integrate (myproc)
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 the Higgs mass value that is inserted is the value in place when
 \ttt{integrate} is evaluated, $150\;\GeV$ in this example.  This same value
 will also be used when the process is called by a subsequent \ttt{simulate};
 it is \ttt{integrate} which compiles the cut expression and stores it among
 the process data.  This behavior allows for scanning over parameters without
 redefining the cuts every time.
 
 The cut expression can make use of all variables and constructs that are
 defined at the point where it is evaluated.  In particular, it can make use of
 the particle content and kinematics of the hard process, as in the example
 above.  In addition to the predefined variables and those defined by the user,
 there are the following variables which depend on the hard process:
 \begin{quote}
 \begin{tabular}{ll}
 integer: & \ttt{n\_in}, \ttt{n\_out}, \ttt{n\_tot} \\
 real: & \ttt{sqrts}, \ttt{sqrts\_hat}
 \end{tabular}
 \end{quote}
 Example:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 cuts = sqrts_hat > 150 GeV
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The constants \ttt{n\_in} etc.\ are sometimes useful if a generic set of cuts
 is defined, which applies to various processes simultaneously.
 
 The user is encouraged to define his/her own set of cuts, if possible in a
 process-independent manner, even if it is not required.  The \ttt{include}
 command allows for storing a set of cuts in a separate \sindarin\ script which
 may be read in anywhere.  As an example, the system directories contain a file
 \verb|default_cuts.sin| which may be invoked by
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 include ("default_cuts.sin")
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 
 \subsection{QCD scale and coupling}
 
 \whizard\ treats all physical parameters of a model, the coefficients in the
 Lagrangian, as constants.  As a leading-order program, \whizard\ does not make
 use of running parameters as they are described by renormalization theory.
 For electroweak interactions where the perturbative expansion is sufficiently
 well behaved, this is a consistent approach.
 
 As far as QCD is concerned, this approach does not yield numerically
 reliable results, even on the validity scale of the tree approximation.
 In \whizard\ttt{2}, it is therefore possible to replace the fixed value of
 $\alpha_s$ (which is accessible as the intrinsic model variable
 \verb|alphas|), by a function of an energy scale $\mu$.
 
 This is controlled by the parameter \verb|?alphas_is_fixed|, which is
 \ttt{true} by default.  Setting it to \ttt{false} enables running~$\alpha_s$.
 The user has then to decide how $\alpha_s$ is calculated.
 
 One option is to set \verb|?alphas_from_lhapdf| (default \ttt{false}).  This
 is recommended if the \lhapdf\ library is used for including structure
 functions, but it may also be set if \lhapdf\ is not invoked.  \whizard\ will
 then use the $\alpha_s$ formula and value that matches the active
 \lhapdf\ structure function set and member.
 
 In the very same way, the $\alpha_s$ running from the PDFs implemented
 intrinsically in \whizard\ can be taken by setting
 \verb|?alphas_from_pdf_builtin| to \ttt{true}. This is the same
 running then the one from \lhapdf, if the intrinsic PDF coincides with
 a PDF chosen from \lhapdf.
 
 If this is not appropriate, there are again two possibilities.  If
 \verb|?alphas_from_mz| is \ttt{true}, the user input value \verb|alphas| is
 interpreted as the running value $\alpha_s(m_Z)$, and for the particular
 event, the coupling is evolved to the appropriate scale $\mu$.  The formula is
 controlled by the further parameters \verb|alphas_order| (default $0$,
 meaning leading-log; maximum $2$) and \verb|alphas_nf| (default $5$).
 
 Otherwise there is the option to set \verb|?alphas_from_lambda_qcd = true|
 in order to evaluate $\alpha_s$ from the scale $\Lambda_{\rm QCD}$,
 represented by the intrinsic variable \verb|lambda_qcd|. The reference
 value for the QCD scale is $\Lambda\_{\rm QCD} = 200$
 MeV. \verb|alphas_order| and \verb|alphas_nf| apply analogously.
 
 Note that for using one of the running options for $\alpha_s$, always
 \ttt{?alphas\_is\_fixed = false} has to be invoked.
 
 In any case, if $\alpha_s$ is not fixed, each event has to be assigned an
 energy scale.  By default, this is $\sqrt{\hat s}$, the partonic invariant
 mass of the event.  This can be replaced by a user-defined scale, the special
 object \ttt{scale}.  This is assigned and used just like the \ttt{cuts}
 object.  The right-hand side is a real-valued expression.  Here is an example:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 scale = eval Pt [sort by -Pt [colored]]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 This selects the $p_T$ value of the first entry in the list of colored
 particles sorted by decreasing $p_T$, i.e., the $p_T$ of the hardest jet.
 
 The \ttt{scale} definition is used not just for running $\alpha_s$ (if
 enabled), but it is also the factorization scale for the \lhapdf\ structure
 functions.
 
 These two values can be set differently by specifying
 \ttt{factorization\_scale} for the scale at which the PDFs are
 evaluated. Analogously, there is a variable
 \ttt{renormalization\_scale} that sets the scale value for the running
 $\alpha_s$. Whenever any of these two values is set, it supersedes the
 \ttt{scale} value.
 
 Just like the \ttt{cuts} expression, the expressions for \ttt{scale},
 \ttt{factorization\_scale} and also \ttt{renormalization\_scale}
 are evaluated at the point where it is read by an explicit or implicit
 \ttt{integrate} command.
 
 
 \subsection{Reweighting factor}
 
 It is possible to reweight the integrand by a user-defined function of the
 event kinematics.  This is done by specifying a \ttt{weight} expression.
 Syntax and usage is exactly analogous to the \ttt{scale} expression.  Example:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 weight = eval (1 + cos (Theta) ^ 2) [lepton]
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 We should note that the phase-space setup is not aware of this reweighting, so
 in complicated cases you should not expect adaptation to achieve as accurate
 results as for plain cross sections.
 
 Needless to say, the default \ttt{weight} is unity.
 
 
 \section{Events}
 
 After the cross section integral of a scattering process is known (or the
 partial-width integral of a decay process), \whizard\ can generate event
 samples.  There are two limiting cases or modes of event generation:
 \begin{enumerate}
 \item
   For a physics simulation, one needs \emph{unweighted} events, so the
   probability of a process and a kinematical configuration in the event sample
   is given by its squared matrix element.
 \item
   Monte-Carlo integration yields \emph{weighted} events, where the probability
   (without any grid adaptation) is uniformly distributed over phase space,
   while the weight of the event is given by its squared matrix element.
 \end{enumerate}
 The choice of parameterizations and the iterative adaptation of the
 integration grids gradually shift the generation mode from option 2 to option
 1, which obviously is preferred since it simulates the actual outcome of an
 experiment.  Unfortunately, this adaptation is perfect only in trivial cases,
 such that the Monte-Carlo integration yields non-uniform probability still
 with weighted events.  Unweighted events are obtained by rejection, i.e.,
 accepting an event with a probability equal to its own weight divided by the
 maximal possible weight.  Furthermore, the maximal weight is never precisely
 known, so this probability can only be estimated.
 
 The default generation mode of \whizard\ is unweighted.  This is controlled by
 the parameter \verb|?unweighted| with default value \ttt{true}.  Unweighted
 events are easy to interpret and can be directly compared with experiment, if
 properly interfaced with detector simulation and analysis.
 
 However, when applying rejection to generate unweighted events, the generator
 discards information, and for a single event it needs, on the average,
 $1/\epsilon$ calls, where the efficiency $\epsilon$ is the ratio of the
 average weight over the maximal weight.  If \verb|?unweighted| is \ttt{false},
 all events are kept and assigned their respective weights in histograms or
 event files.
 
 
 \subsection{Simulation}
 \label{sec:simulation}
 
 The \ttt{simulate} command generates an event sample.  The number of events
 can be set either by specifying the integer variable \verb|n_events|, or by
 the real variable \verb|luminosity|.  (This holds for unweighted events.  If
 weighted events are requested, the luminosity value is ignored.)  The
 luminosity is measured in
 femtobarns, but other units can be used, too.  Since the cross sections for the
 processes are known at that point, the number of events is determined as the
 luminosity multiplied by the cross section.
 
 As usual, both parameters can be set either as global or as local parameters:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   n_events = 10000
   simulate (proc1)
   simulate (proc2, proc3) { luminosity = 100 / 1 pbarn }
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 In the second example, both \verb|n_events| and \verb|luminosity| are set.
 In that case, \whizard\ chooses whatever produces the larger number of events.
 
 If more than one process is specified in the argument of \ttt{simulate},
 events are distributed among the processes with fractions proportional to
 their cross section values.  The processes are mixed randomly, as it would be
 the case for real data.
 
 The raw event sample is written to a file which is named after the first process
 in the argument of \ttt{simulate}.  If the process name is \ttt{proc1}, the
 file will be named \ttt{proc1.evx}.  You can choose another basename by the
 string variable \verb|$sample|.  For instance,
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   simulate (proc1) { n_events = 4000  $sample = "my_events" }
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 will produce an event file \verb|my_events.evx| which contains $4000$ events.
 
 This event file is in a machine-dependent binary format, so it is not of
 immediate use.  Its principal purpose is to serve as a cache: if you re-run
 the same script, before starting simulation, it will look for an existing
 event file that matches the input.  If nothing has changed, it will find the
 file previously generated and read in the events, instead of generating them.
 Thus you can modify the analysis or any further steps without repeating the
 time-consuming task of generating a large event sample.  If you change the
 number of events to generate, the program will make use of the existing event
 sample and generate further events only when it is used up.  If necessary, you
 can suppress the writing/reading of the raw event file by the parameters
 \verb|?write_raw| and \verb|?read_raw|.
 
 If you try to reuse an event file that has been written by a previous version
 of \whizard, you may run into an incompatibility, which will be detected as an
 error.  If this happens, you may enforce a compatibility mode (also for
 writing) by setting \ttt{\$event\_file\_version} to the appropriate version
 string, e.g., \verb|"2.0"|.  Be aware that this may break some more recent
 features in the event analysis.
 
 Generating an event sample can serve several purposes.  First of all,
 it can be analyzed directly, by \whizard's built-in capabilities, to
 produce tables, histograms, or calculate inclusive observables.  The
 basic analysis features of \whizard\ are described below in
 Sec.~\ref{sec:analysis}.  It can be written to an external file in a
 standard format that a human or an external program can understand.
 In Chap.~\ref{chap:events}, you will find a more thorough discussion
 of event generation with \whizard, which also covers in detail the
 available event-file formats.  Finally, \whizard\ can rescan an
 existing event sample.  The event sample may either be the result of a
 previous \ttt{simulate} run or, under certain conditions, an external
 event sample produced by another generator or reconstructed from
 data.
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 rescan "my_events" (proc1) { $pdf_builtin_set = "MSTW2008LO" }
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The rescanning may apply different parameters and recalculate the
 matrix element, it may apply a different event selection, it may
 reweight the events by a different PDF set (as above).  The modified
 event sample can again be analyzed or written to file.  For more
 details, cf.\ Sec.~\ref{sec:rescan}.
 
 %%%%%%%%%%%%%%%
 
 \subsection{Decays}
 \label{sec:decays}
 
 Normally, the events generated by the \ttt{simulate} command will be identical
 in structure to the events that the \ttt{integrate} command generates.  This
 implies that for a process such as $pp\to W^+W^-$, the final-state particles
 are on-shell and stable, so they appear explicitly in the generated event
 files.  If events are desired where the decay products of the $W$ bosons
 appear, one has to generate another process, e.g., $pp\to u\bar d\bar ud$.  In
 this case, the intermediate vector bosons, if reconstructed, are off-shell as
 dictated by physics, and the process contains all intermediate states that are
 possible.  In this example, the matrix element contains also $ZZ$, photon, and
 non-resonant intermediate states.  (This can be restricted via the
 \verb|$restrictions| option, cf.\ \ref{sec:process options}.
 
 Another approach is to factorize the process in production (of $W$ bosons) and
 decays ($W\to q\bar q$).  This is actually the traditional approach, since it
 is much less computing-intensive.  The factorization neglects all off-shell
 effects and irreducible background diagrams that do not have the decaying
 particles as an intermediate resonance.  While \whizard\ is able to deal with
 multi-particle processes without factorization, the needed computing resources
 rapidly increase with the number of external particles. Particularly,
 it is the phase space integration that becomes the true bottleneck for
 a high multiplicity of final state particles.
 
 In order to use the factorized approach, one has to specify particles
 as \ttt{unstable}.  (Also, the \ttt{?allow\_decays} switch must be \ttt{true};
 this is however its default value.)  We give an example for a $pp \to Wj$ final
 state:
 \begin{code}
 process wj  = u, gl => d, Wp
 process wen = Wp => E1, n1
 
 integrate (wen)
 
 sqrts = 7 TeV
 beams = p, p => pdf_builtin
 unstable Wp (wen)
 simulate (wj) { n_events = 1 }
 \end{code}
 This defines a $2 \to 2$ hard scattering process of $W + j$ production
 at the 7 TeV LHC 2011 run. The $W^+$ is marked as unstable, with its
 decay process being $W^+ \to e^+ \nu_e$. In the \ttt{simulate} command
 both processes, the production process \ttt{wj} and the decay process
 \ttt{wen} will be integrated, while the $W$ decays become effective
 only in the final event sample. This event sample will contain final
 states with multiplicity $3$, namely $e^+ \nu_e d$. Note that here
 only one decay process is given, hence the branching ratio for the
 decay will be taken to be $100 \%$ by \whizard.
 
 A natural restriction of the factorized approach is the implied narrow-width
 approximation.  Theoretically, this restriction is necessary since whenever
 the width plays an important role, the usage of the factorized approach will
 not be fully justified.  In particular, all involved matrix elements must be
 evaluated on-shell, or otherwise gauge-invariance issues could spoil the
 calculation.  (There are plans for a future \whizard\ version
 to also include Breit-Wigner or Gaussian distributions when using the
 factorized approach.)
 
 Decays can be concatenated, e.g. for top pair production and
 decay, $e^+ e^- \to t \bar t$ with decay $t \to W^+ b$, and subsequent
 leptonic decay of the $W$ as in $W^+ \to \mu^+ \nu_\mu$:
 \begin{code}
 process eett = e1, E1 => t, tbar
 process t_dec = t => Wp, b
 process W_dec = Wp => E2, n2
 
 unstable t (t_dec)
 unstable Wp (W_dec)
 
 sqrts = 500
 simulate (eett) { n_events = 1 }
 \end{code}
 Note that in this case the final state in the event file will consist
 of $\bar t b \mu^+ \nu_\mu$ because the anti-top is not decayed.
 
 If more than one decay process is being specified like in
 \begin{code}
   process eeww = e1, E1 => Wp, Wm
   process w_dec1 = Wp => E2, n2
   process w_dec2 = Wp => E3, n3
 
   unstable Wp (w_dec1, w_dec2)
 
   sqrts = 500
   simulate (eeww) { n_events = 100 }
 \end{code}
 then \whizard\ takes the integrals of the specified decay processes
 and distributes the decays statistically according to the calculated
 branching ratio. Note that this might not be the true branching ratios
 if decay processes are missing, or loop corrections to partial widths
 give large(r) deviations. In the calculation of the code above,
 \whizard\ will issue an output like
 \begin{code}
 | Unstable particle W+: computed branching ratios:
 |   w_dec1: 5.0018253E-01   mu+, numu
 |   w_dec2: 4.9981747E-01   tau+, nutau
 |   Total width = 4.5496085E-01 GeV (computed)
 |               = 2.0490000E+00 GeV (preset)
 |   Decay options: helicity treated exactly
 \end{code}
 So in this case, \whizard\ uses 50 \% muonic and 50 \% tauonic decays
 of the positively charged $W$, while the $W^-$ appears directly in the
 event file. \whizard\ shows the difference between the preset $W$
 width from the physics model file and the value computed from the two
 decay channels.
 
 Note that a particle in a \sindarin\ input script can be also explictly
 marked as being stable, using the
 \begin{code}
 stable <particle-tag>
 \end{code}
 constructor for the particle \ttt{<particle-tag>}.
 
 
 \subsubsection{Resetting branching fractions}
 \label{sec:br-reset}
 
 As described above, decay processes that appear in a simulation must
 first be integrated by the program, either explicitly via the
 \verb|integrate| command, or implicitly by \verb|unstable|.  In either
 case, \whizard\ will use the computed partial widths in order to
 determine branching fractions.  In the spirit of a purely leading-order
 calculation, this is consistent.
 
 However, it may be desired to rather use different branching-fraction
 values for the decays of a particle, for instance, NLO-corrected
 values.  In fact, after \whizard\ has integrated any process, the
 integration result becomes available as an ordinary
 \sindarin\ variable.  For instance, if a decay process has the ID
 \verb|h_bb|, the integral of this process -- the partial width, in
 this case -- becomes the variable \verb|integral(h_bb)|.  This
 variable may be reset just like any other variable:
 \begin{code}
   integral(h_bb) = 2.40e-3 GeV
 \end{code}
 The new value will be used for all subsequent Higgs branching-ratio
 calculations and decays, if an unstable Higgs appears in a process for
 simulation.
 
 
 \subsubsection{Spin correlations in decays}
 \label{sec:spin-correlations}
 
 By default, \whizard\ applies full spin and color correlations to the
 factorized processes, so it keeps both color and spin coherence between
 productions and decays.  Correlations between decay products of distinct
 unstable particles in the same event are also fully retained.  The program
 sums over all intermediate quantum numbers.
 
 Although this approach obviously yields the optimal description with the
 limits of production-decay factorization, there is support for a simplified
 handling of particle decays.  Essentially, there are four options, taking a
 decay \ttt{W\_ud}: $W^-\to \bar u d$ as an example:
 \begin{enumerate}
 \item
   Full spin correlations: \verb|unstable Wp (W_ud)|
 \item
   Isotropic decay: \verb|unstable Wp (W_ud) { ?isotropic_decay = true }|
 \item
   Diagonal decay matrix:
   \verb|unstable Wp (W_ud) { ?diagonal_decay = true }|
 \item
   Project onto specific helicity:
   \verb|unstable Wp (W_ud) { decay_helicity = -1 }|
 \end{enumerate}
 Here, the isotropic option completely eliminates spin correlations.  The
 diagonal-decays option eliminates just the off-diagonal entries of the $W$
 spin-density matrix.  This is equivalent to a measurement of spin before the
 decay.  As a result, spin correlations are still present in the classical
 sense, while quantum coherence is lost.  The definite-helicity option is
 similar and additional selects only the specified helicity component for the
 decaying particle, so its decay distribution assumes the shape for an
 accordingly polarized particle.  All options apply in the rest frame of the
 decaying particle, with the particle's momentum as the quantization axis.
 
 \subsubsection{Automatic decays}
 
 A convenient option is if the user did not have to specify the decay
 mode by hand, but if they were generated automatically. \whizard\ does
 have this option: the flag \ttt{?auto\_decays} can be set to
 \ttt{true}, and is taking care of that. In that case the list for the
 decay processes of the particle marked as unstable is left empty (we
 take a $W^-$ again as example):
 \begin{code}
 unstable Wm () { ?auto_decays = true }
 \end{code}
 \whizard\ then inspects at the local position within the \sindarin\
 input file where that \ttt{unstable} statement appears the masses of
 all the particles of the active physics model in order to determine
 which decays are possible. It then calculates their partial widths.
 There are a few options to customize the decays. The integer variable
 \ttt{auto\_decays\_multiplicity} allows to set the maximal
 multiplicity of the final states considered in the auto decay
 option. The defaul value of that variable is \ttt{2}; please be quite
 careful when setting this to values larger than that. If you do so,
 the flag \ttt{?auto\_decays\_radiative} allows to specify whether
 final states simply containing additional resolved gluons or photons
 are taken into account or not. For the example above, you almost hit
 the PDG value for the $W$ total width:
 \begin{code}
 | Unstable particle W-: computed branching ratios:
 |   decay_a24_1: 3.3337068E-01   d, ubar
 |   decay_a24_2: 3.3325864E-01   s, cbar
 |   decay_a24_3: 1.1112356E-01   e-, nuebar
 |   decay_a24_4: 1.1112356E-01   mu-, numubar
 |   decay_a24_5: 1.1112356E-01   tau-, nutaubar
 |   Total width = 2.0478471E+00 GeV (computed)
 |               = 2.0490000E+00 GeV (preset)
 |   Decay options: helicity treated exactly
 \end{code}
 
 \subsubsection{Future shorter notation for decays}
 
 {\color{red} In an upcoming \whizard\ version there will be a shorter and more
   concise notation already in the process definition for such decays,
   which, however, is current not yet implemented. The two first examples
   above will then be shorter and have this form:}
   \begin{code}
     process wj = u, gl => (Wp => E1, n1), d
   \end{code}
   {\color{red} as well as }
   \begin{code}
     process eett = e1, E1 => (t => (Wp => E2, n2), b), tbar
   \end{code}
 
 %%%%%
 
 \subsection{Event formats}
 
 As mentioned above, the internal \whizard\ event format is a
 machine-dependent event format. There are a series of human-readable
 ASCII event formats that are supported: very verbose formats intended
 for debugging, formats that have been agreed upon during the Les
 Houches workshops like LHA and LHEF, or formats that are steered
 through external packages like HepMC. More details about event formats
 can be found in Sec.~\ref{sec:eventformats}.
 
 %%%%%%%%%%%%%%%
 
 \section{Analysis and Visualization}
 \label{sec:analysis}
 
 \sindarin\ natively supports basic methods of data analysis and visualization
 which are frequently used in high-energy physics studies.  Data generated
 during script execution, in particular simulated event samples, can be
 analyzed to evaluate further observables, fill histograms, and draw
 two-dimensional plots.
 
 So the user does not have to rely on his/her own external graphical
 analysis method (like e.g. \ttt{gnuplot} or \ttt{ROOT} etc.), but can
 use methods that automatically ship with \whizard. In many cases, the
 user, however, clearly will use his/her own analysis machinery,
 especially experimental collaborations.
 
 In the following sections, we first summarize the available data structures,
 before we consider their graphical display.
 
 
 
 \subsection{Observables}
 
 Analyses in high-energy physics often involve averages of quantities other
 than a total cross section.  \sindarin\ supports this by its \ttt{observable}
 objects.  An \ttt{observable} is a container that collects a single
 real-valued variable with a statistical distribution.  It is declared by a
 command of the form
 \begin{quote}
   \begin{footnotesize}
 \ttt{observable \emph{analysis-tag}}
   \end{footnotesize}
 \end{quote}
 where \ttt{\emph{analysis-tag}} is an identifier that follows the same rules
 as a variable name.
 
 Once the observable has been declared, it can be filled with values.  This is
 done via the \ttt{record} command:
 \begin{quote}
   \begin{footnotesize}
 \ttt{record \emph{analysis-tag} (\emph{value})}
   \end{footnotesize}
 \end{quote}
 To make use of this, after values have been filled, we want to perform the
 actual analysis and display the results.  For an observable, these are the
 mean value and the standard deviation.  There is the command
 \ttt{write\_analysis}:
 \begin{quote}
   \begin{footnotesize}
 \ttt{write\_analysis (\emph{analysis-tag})}
   \end{footnotesize}
 \end{quote}
 
 Here is an example:
 \begin{quote}
   \begin{footnotesize}
 \begin{verbatim}
 observable obs
 record obs (1.2)  record obs (1.3)  record obs (2.1)  record obs (1.4)
 write_analysis (obs)
 \end{verbatim}
   \end{footnotesize}
 \end{quote}
 The result is displayed on screen:
 \begin{quote}
   \begin{footnotesize}
 \begin{verbatim}
 ###############################################################################
 # Observable: obs
 average     =  1.500000000000E+00
 error[abs]  =  2.041241452319E-01
 error[rel]  =  1.360827634880E-01
 n_entries   = 4
 \end{verbatim}
   \end{footnotesize}
 \end{quote}
 
 
 \subsection{The analysis expression}
 \label{subsec:analysis}
 
 The most common application is the computation of event observables -- for
 instance, a forward-backward asymmetry -- during simulation.  To this end,
 there is an \ttt{analysis} expression, which behaves very similar to the
 \ttt{cuts} expression.  It is defined either globally
 \begin{quote}
   \begin{footnotesize}
     \ttt{analysis = \emph{logical-expr}}
   \end{footnotesize}
 \end{quote}
 or as a local option to the \ttt{simulate} or \ttt{rescan} commands which
 generate and handle event samples.  If this expression is defined, it is not
 evaluated immediately, but it is evaluated once for each event in the sample.
 
 In contrast to the \ttt{cuts} expression, the logical value of the
 \ttt{analysis} expression is discarded; the expression form has been chosen
 just by analogy.  To make this useful, there is a variant of the \ttt{record}
 command, namely a \ttt{record} function with exactly the same syntax.  As an
 example, here is a calculation of the forward-backward symmetry in a process
 \ttt{ee\_mumu} with final state $\mu^+\mu^-$:
 \begin{quote}
   \begin{footnotesize}
 \begin{verbatim}
   observable a_fb
   analysis = record a_fb (eval sgn (Pz) ["mu-"])
   simulate (ee_mumu) { luminosity = 1 / 1 fbarn }
 \end{verbatim}
   \end{footnotesize}
 \end{quote}
 The logical return value of \ttt{record} -- which is discarded here -- is
 \ttt{true} if the recording was successful.  In case of histograms (see below)
 it is true if the value falls within bounds, false otherwise.
 
 Note that the function version of \ttt{record} can be used anywhere in
 expressions, not just in the \ttt{analysis} expression.
 
 When \ttt{record} is called for an observable or histogram in simulation mode,
 the recorded value is weighted appropriately.  If \ttt{?unweighted} is true,
 the weight is unity, otherwise it is the event weight.
 
 The \ttt{analysis} expression can involve any other construct
 that can be expressed as an expression in \sindarin.  For instance, this
 records the energy of the 4th hardest jet in a histogram \ttt{pt\_dist}, if it
 is in the central region:
 \begin{quote}
   \begin{footnotesize}
 \begin{verbatim}
   analysis =
     record pt_dist (eval E [extract index 4
                              [sort by - Pt
                                [select if -2.5 < Eta < 2.5 [colored]]]])
 \end{verbatim}
   \end{footnotesize}
 \end{quote}
 Here, if there is no 4th jet in the event which satisfies the criterion, the
 result will be an undefined value which is not recorded.  In that case,
 \ttt{record} evaluates to \ttt{false}.
 
 Selection cuts can be part of the analysis expression:
 \begin{code}
   analysis =
     if any Pt > 50 GeV [lepton] then
       record jet_energy (eval E [collect [jet]])
     endif
 \end{code}
 Alternatively, we can specify a separate selection expression:
 \begin{code}
   selection = any Pt > 50 GeV [lepton]
   analysis = record jet_energy (eval E [collect [jet]])
 \end{code}
 The former version writes all events to file (if requested), but
 applies the analysis expression only to the selected events.  This
 allows for the simultaneous application of different selections to a
 single event sample.  The latter version applies the selection to all
 events before they are analyzed or written to file.
 
 The analysis expression can make use of all variables and constructs that are
 defined at the point where it is evaluated.  In particular, it can make use of
 the particle content and kinematics of the hard process, as in the example
 above.  In addition to the predefined variables and those defined by the user,
 there are the following variables which depend on the hard process.  Some of
 them are constants, some vary event by event:
 \begin{quote}
 \begin{tabular}{ll}
 integer: &\ttt{event\_index} \\
 integer: &\ttt{process\_num\_id} \\
 string: &\ttt{\$process\_id} \\
 integer: &\ttt{n\_in}, \ttt{n\_out}, \ttt{n\_tot} \\
 real: &\ttt{sqrts}, \ttt{sqrts\_hat} \\
 real: &\ttt{sqme}, \ttt{sqme\_ref} \\
 real: &\ttt{event\_weight}, \ttt{event\_excess}
 \end{tabular}
 \end{quote}
 The \ttt{process\_num\_id} is the numeric ID as used by external
 programs, while the process index refers to the current library. By
 default, the two are identical.  The process index itself is not
 available as a predefined observable. The \ttt{sqme} and
 \ttt{sqme\_ref} values indicate the squared matrix element and the
 reference squared matrix element, respectively.  The latter applies
 when comparing with a reference sample (the \ttt{rescan} command).
 
 \ttt{record} evaluates to a logical, so several \ttt{record} functions may
 be concatenated by the logical operators \ttt{and} or \ttt{or}.  However,
 since usually the further evaluation should not depend on the return value of
 \ttt{record}, it is more advisable to concatenate them by the semicolon
 (\ttt{;}) operator.  This is an operator (\emph{not} a statement separator or
 terminator) that connects two logical expressions and evaluates both of them
 in order.  The lhs result is discarded, the result is the value of the rhs:
 \begin{quote}
   \begin{footnotesize}
 \begin{verbatim}
   analysis =
     record hist_pt (eval Pt [lepton]) ; record hist_ct (eval cos (Theta) [lepton])
 \end{verbatim}
   \end{footnotesize}
 \end{quote}
 
 
 \subsection{Histograms}
 \label{sec:histogram}
 
 In \sindarin, a histogram is declared by the command
 \begin{quote}
   \begin{footnotesize}
 \ttt{histogram \emph{analysis-tag} (\emph{lower-bound}, \emph{upper-bound})}
   \end{footnotesize}
 \end{quote}
 This creates a histogram data structure for an (unspecified) observable.  The
 entries are organized in bins between the real values \ttt{\emph{lower-bound}}
 and \ttt{\emph{upper-bound}}.  The number of bins is given by the value of the
 intrinsic integer variable \ttt{n\_bins}, the default value is 20.
 
 The \ttt{histogram} declaration supports an optional argument, so the number
 of bins can be set locally, for instance
 \begin{quote}
   \begin{footnotesize}
 \ttt{histogram pt\_distribution (0 GeV, 500 GeV) \{ n\_bins = 50 \}}
   \end{footnotesize}
 \end{quote}
 Sometimes it is more convenient to set the bin width directly.  This can be
 done in a third argument to the \ttt{histogram} command.
 \begin{quote}
   \begin{footnotesize}
 \ttt{histogram pt\_distribution (0 GeV, 500 GeV, 10 GeV)}
   \end{footnotesize}
 \end{quote}
 If the bin width is specified this way, it overrides the setting of
 \ttt{n\_bins}.
 
 The \ttt{record} command or function fills histograms.  A single call
 \begin{quote}
   \begin{footnotesize}
 \ttt{record (\emph{real-expr})}
   \end{footnotesize}
 \end{quote}
 puts the value of \ttt{\emph{real-expr}} into the appropriate bin.  If
 the call is issued during a simulation where \ttt{unweighted} is false, the
 entry is weighted appropriately.
 
 If the value is outside the range specified in the histogram declaration, it
 is put into one of the special underflow and overflow bins.
 
 The \ttt{write\_analysis} command prints the histogram contents as a table in
 blank-separated fixed columns.  The columns are: $x$ (bin midpoint), $y$ (bin
 contents), $\Delta y$ (error), excess weight, and $n$ (number of entries).
 The output also contains comments initiated by a \verb|#| sign, and following
 the histogram proper, information about underflow and overflow as well as
 overall contents is added.
 
 
 \subsection{Plots}
 \label{sec:plot}
 
 While a histogram stores only summary information about a data set, a
 \ttt{plot} stores all data as $(x,y)$ pairs, optionally with errors.  A plot
 declaration is as simple as
 \begin{quote}
   \begin{footnotesize}
 \ttt{plot \emph{analysis-tag}}
   \end{footnotesize}
 \end{quote}
 Like observables and histograms, plots are filled by the \ttt{record} command
 or expression.  To this end, it can take two arguments,
 \begin{quote}
   \begin{footnotesize}
 \ttt{record (\emph{x-expr}, \emph{y-expr})}
   \end{footnotesize}
 \end{quote}
 or up to four:
 \begin{quote}
   \begin{footnotesize}
 \ttt{record (\emph{x-expr}, \emph{y-expr}, \emph{y-error})}
 \\
 \ttt{record (\emph{x-expr}, \emph{y-expr},
   \emph{y-error-expr}, \emph{x-error-expr})}
   \end{footnotesize}
 \end{quote}
 Note that the $y$ error comes first.  This is because applications will
 demand errors for the $y$ value much more often than $x$ errors.
 
 The plot output, again written by \ttt{write\_analysis} contains the four
 values for each point, again in the ordering $x,y,\Delta y, \Delta x$.
 
 
 \subsection{Analysis Output}
 
 There is a default format for piping information into observables,
 histograms, and plots. In older versions of \whizard\ there was a
 first version of a custom format, which was however rather limited.
 A more versatile custom output format will be coming soon.
 
 \begin{enumerate}
 \item
 By default, the \ttt{write\_analysis} command prints all data to the
 standard output. The data are also written to a default file with the
 name \ttt{whizard\_analysis.dat}.
 Output is redirected to a file with a different name if the
 variable \ttt{\$out\_file} has a nonempty value.  If the file is
 already open, the output will be appended to
 the file, and it will be kept open.  If the file is not open,
 \ttt{write\_analysis} will open the output file by itself, overwriting any
 previous file with the same name, and close it again after data have been
 written.
 
 The command is able to print more than one dataset, following the syntax
 \begin{quote}
   \begin{footnotesize}
   \ttt{write\_analysis (\emph{analysis-tag1}, \emph{analysis-tag2}, \ldots)
   \{ \emph{options} \}}
   \end{footnotesize}
 \end{quote}
 The argument in brackets may also be empty or absent; in this case, all
 currently existing datasets are printed.
 
 The default data format is suitable for compiling analysis data by \whizard's
 built-in \gamelan\ graphics driver (see below and particularly
 Chap.~\ref{chap:visualization}).  Data are written in
 blank-separated fixed columns, headlines and comments are initiated by the
 \verb|#| sign, and each data set is terminated by a blank line.  However,
 external programs often require special formatting.
 
 The internal graphics driver \gamelan\ of \whizard\ is initiated by
 the \ttt{compile\_analysis} command. Its syntax is the same, and it
 contains the \ttt{write\_analysis} if that has not been separately
 called (which is unnecessary). For more details about the \gamelan\
 graphics driver and data visualization within \whizard, confer
 Chap.~\ref{chap:visualization}.
 
 \item
 Custom format. Not yet (re-)implemented in a general form.
 \end{enumerate}
 
 
 \section{Custom Input/Output}
 \label{sec:I/O}
 
 \whizard\ is rather chatty.  When you run examples or your own scripts, you
 will observe that the program echoes most operations (assignments, commands,
 etc.) on the standard output channel, i.e., on screen.  Furthermore, all
 screen output is copied to a log file which by default is named
 \ttt{whizard.log}.
 
 For each integration run, \whizard\ writes additional process-specific
 information to a file \ttt{\var{tag}.log}, where \ttt{\var{tag}} is the
 process name.  Furthermore, the \ttt{write\_analysis} command dumps analysis
 data -- tables for histograms and plots -- to its own set of files, cf.\
 Sec.~\ref{sec:analysis}.
 
 However, there is the occasional need to write data to extra files in a custom
 format.  \sindarin\ deals with that in terms of the following commands:
 
 \subsection{Output Files}
 
 \subsubsection{open\_out}
 \begin{syntax}
 open\_out (\var{filename}) \\
 open\_out (\var{filename}) \{ \var{options} \}
 \end{syntax}
 Open an external file for writing.  If the file exists, it is overwritten
 without warning, otherwise it is created.  Example:
 \begin{code}
 open_out ("my_output.dat")
 \end{code}
 
 
 \subsubsection{close\_out}
 \begin{syntax}
 close\_out (\var{filename}) \\
 close\_out (\var{filename}) \{ \var{options} \}
 \end{syntax}
 Close an external file that is open for writing.  Example:
 \begin{code}
 close_out ("my_output.dat")
 \end{code}
 
 
 \subsection{Printing Data}
 
 \subsubsection{printf}
 \begin{syntax}
 printf \var{format-string-expr} \\
 printf \var{format-string-expr} (\var{data-objects})
 \end{syntax}
 Format \ttt{\var{data-objects}} according to \ttt{\var{format-string-expr}}
 and print the resulting string to standard output if the string variable
 \ttt{\$out\_file} is undefined.  If \ttt{\$out\_file} is defined and the file
 with this name is open for writing, print to this file instead.
 
 Print a newline at the end if \ttt{?out\_advance} is true, otherwise don't
 finish the line.
 
 The \ttt{\var{format-string-expr}} must evaluate to a string.  Formatting
 follows a subset of the rules for the \ttt{printf(3)} command in the \ttt{C}
 language.  The supported rules are:
 \begin{itemize}
 \item All characters are printed as-is, with the exception of embedded
   conversion specifications.
 \item Conversion specifications are initiated by a percent (\verb|%|) sign and
   followed by an optional prefix flag, an optional integer value, an optional
   dot followed by another integer, and a mandatory letter as the conversion
   specifier.
 \item A percent sign immediately followed by another percent sign is
   interpreted as a single percent sign, not as a conversion specification.
 \item The number of conversion specifiers must be equal to the number of data
   objects.  The data types must also match.
 \item The first integer indicates the minimum field width, the second one the
   precision.  The field is expanded as needed.
 \item The conversion specifiers \ttt{d} and \ttt{i} are equivalent, they
   indicate an integer value.
 \item The conversion specifier \ttt{e} indicates a real value that should be
   printed in exponential notation.
 \item The conversion specifier \ttt{f} indicates a real value that should be
   printed in decimal notation without exponent.
 \item The conversion specifier \ttt{g} indicates a real value that should be
   printed either in exponential or in decimal notation, depending on its
   value.
 \item The conversion specifier \ttt{s} indicates a logical or string value
   that should be printed as a string.
 \item Possible prefixes are \verb|#| (alternate form, mandatory decimal point
   for reals), \verb|0| (zero padding), \verb|-| (left adjusted), \verb|+|
   (always print sign), `\verb| |' (print space before a positive number).
 \end{itemize}
 For more details, consult the \verb|printf(3)| manpage.  Note that other
 conversions are not supported and will be rejected by \whizard.
 
 The data arguments are numeric, logical or string variables or expressions.
 Numeric expressions must be enclosed in parantheses.  Logical expressions must
 be enclosed in parantheses prefixed by a question mark \verb|?|.  String
 expressions must be enclosed in parantheses prefixed by a dollar sign
 \verb|$|.  These forms behave as anonymous variables.
 
 Note that for simply printing a text string, you may call \ttt{printf} with
 just a format string and no data arguments.
 
 Examples:
 \begin{code}
 printf "The W mass is %8f GeV" (mW)
 
 int i = 2
 int j = 3
 printf "%i + %i = %i" (i, j, (i+j))
 
 string $directory = "/usr/local/share"
 string $file = "foo.dat"
 printf "File path: %s/%s" ($directory, $file)
 \end{code}
 There is a related \ttt{sprintf} function, cf.~Sec.~\ref{sec:sprintf}.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \section{WHIZARD at next-to-leading order}
 \subsection{Prerequisites}
 A full NLO computation requires virtual matrix elements obtained from
 loop diagrams. Since \oMega\ cannot calculate such diagrams, external
 programs are used.  \whizard\ has a generic interface to matrix-element
 generators that are BLHA-compatible.
 Explicit implementations exist for \gosam, \openloops\ and \recola.
 
 %%%%%
 
 \subsubsection{Setting up \gosam}
 
 The installation of \gosam\ is detailed on the HepForge page
 \url{https://gosam/hepforge.org}.  We mention here some of the steps
 necessary to get it to be linked with \whizard.
 
 {\bf Bug in \gosam\ installation scripts:} In many versions of
 \gosam\ there is a bug in the installation scripts that is only
 relevant if \gosam\ is installed with superuser privileges. Then all
 files in \ttt{\$installdir/share/golem} do not have read privileges
 for normal users. These privileges must be given manually to all files
 in that directory.
 
 Prerequisites for \gosam\ to produce code for one-loop matrix elements
 are the scientific algebra program \ttt{form} and the generator of
 loop topologies and diagrams, \ttt{qgraf}.
 These can be accessed via their respective webpages
 \url{http://www.nikhef.nl/~form/} and
 \url{http://cfif.ist.utl.pt/~paulo/qgraf.html}. Note also that both
 \ttt{Java} and the Java runtime environment have to be installed in
 order for \gosam\ to properly work.  Furthermore, \ttt{libtool}
 needs to be installed.  A more convenient way to install \gosam, is the
 automatic installation script
 \url{https://gosam.hepforge.org/gosam_installer.py}.
 
 %%%%%
 
 \subsubsection{Setting up \openloops}
 \label{sec:openloops-setup}
 
 The installation of \openloops\ is explained in detail on the HepForge
 page \url{https://openloops.hepforge.org}.  In the following, the main
 steps for usage with \whizard\ are summarized.
 
 Please note that at the moment, \openloops\ cannot be installed such
 that in almost all cases the explicit \openloops\ package directory
 has to be set via \ttt{--with-openloops=<openloops\_dir>}.
 
 \openloops\ can be checked out with
 \begin{code}
   git clone https://gitlab.com/openloops/OpenLoops.git
 \end{code}
 Note that \whizard\ only supports \openloops\ version that are at
 least 2.1.1 or newer. Alternatively, one can use the public beta
 version of \openloops, which can be checked out by the command
 \begin{code}
   git clone -b public_beta https://gitlab.com/openloops/OpenLoops.git
 \end{code}
 The program can be build by running \ttt{scons} or \ttt{./scons}, a
 local version that is included in the \openloops\ directory.  This
 produces the script \ttt{./openloops}, which is the main hook for the
 further usage of the program.
 
 \openloops\ works by downloading prebuild process libraries, which have
 to be installed for each individual process. This requires the file
 \ttt{openloops.cfg}, which should contain
 the following content:
 \begin{code}
    [OpenLoops]
    process\_repositories=public, whizard\\
    compile\_extra=1
 \end{code}
 The first line instructs \openloops\ to also look for process libraries
 in an additional lepton collider repository.  The second line triggers
 the inclusion of $N+1$-particle tree-level matrix elements in the
 process directory, so that a complete NLO calculation including real
 amplitudes can be performed only with \openloops.
 
 The libraries can then be installed via
 \begin{code}
    ./openloops libinstall proc_name
 \end{code}
 A list of supported library names can be found on the \openloops\ web
 page.  Note that a process library also includes all possible permutated
 processes.  The process library \ttt{ppllj}, for example, can also be
 used to compute the matrix elements for $e^+ e^- \rightarrow q \bar{q}$
 (massless quarks only).  The massive case of the top quark is handled in
 \ttt{eett}.  Additionally, there are process libraries for top and gauge
 boson decays, \ttt{tbw}, \ttt{vjj}, \ttt{tbln} and \ttt{tbqq}.
 
 Finally, \openloops\ can be linked to \whizard\ during configuration by
 including
 \begin{code}
   --enable-openloops --with-openloops=$OPENLOOPS_PATH,
 \end{code}
 where \ttt{\$OPENLOOPS\_PATH} is the directory the \openloops\
 executable is located in.  \openloops\ one-loop diagrams can then be
 used with the \sindarin\ option
 \begin{code}
   $loop_me_method = "openloops".
 \end{code}
 The functional tests which check the \openloops\ functionality require
 the libraries \ttt{ppllj}, \ttt{eett} and \ttt{tbw} to be installed (note
 that \ttt{eett} is not contained in \ttt{ppll}).  During the
 configuration of \whizard, it is automatically checked that these two
 libraries, as well as the option \ttt{compile\_extra=1}, are present.
 
 \subsubsection{\openloops\ \sindarin\ flags}
 Several \sindarin\ options exist to control the behavior of \openloops.
 \begin{itemize}
   \item \ttt{openloops\_verbosity}:\\
     Decide how much \openloops\ output is printed. Can have values 0, 1
     and 2.
   \item \ttt{?openloops\_use\_cms}:\\
     Activates the complex mass scheme. For computations with decaying
     resonances like the top quark or W or Z bosons, this is the
     preferred option to avoid gauge-dependencies.
   \item \ttt{openloops\_phs\_tolerance}:\\
     Controls the exponent of \ttt{extra psp\_tolerance} in the BLHA
     interface, which is the numerical tolerance for the on-shell
     condition of external particles
   \item \ttt{openloops\_switch\_off\_muon\_yukawa}:\\
     Sets the Yukawa coupling of muons to zero in order to assure
     agreement with \oMega, which is possibly used for other
     components and per default does not take $H\mu\mu$ couplings
     into account.
   \item \ttt{openloops\_stability\_log}:\\
     Creates the directory \ttt{stability\_log}, which contains information
     about the performance of the matrix elements. Possible values are
     \begin{itemize}
     \item 0: No output (default),
     \item 1: On finish() call,
     \item 2: Adaptive,
     \item 3: Always
    \end{itemize}
   \item \ttt{?openloops\_use\_collier}: Use Collier as the reduction
     method (default true).
 \end{itemize}
 
 %%%%%
 
 \subsubsection{Setting up \recola}
 \label{sec:recola-setup}
 
 The installation of \recola\ is explained in detail on the HepForge page
 \url{https://recola.hepforge.org}. In the following the main steps for
 usage with \whizard\ are summarized. The minimal required version number
 of \recola\ is 1.3.0.
 
 \recola\ can be linked to \whizard\ during configuration by including
 \begin{code}
   --enable-recola
 \end{code}
 In case the \recola\ library is not in a standard path or a path
 accessible in the \ttt{LD\_LIBRARY\_PATH} (or
 \ttt{DYLD\_LIBRARY\_PATH}) of the operating system, then the option
 \begin{code}
    --with-recola=$RECOLA_PATH
 \end{code}
 can be set, where \ttt{\$RECOLA\_PATH} is the directory the
 \recola\ library is located in. \recola\ can then be used with the
 \sindarin\ option
 \begin{code}
   $method = "recola"
 \end{code}
 or any other of the matrix element methods.
 
 Note that there might be a clash of the \collier\ libraries when you
 have \collier\ installed both via \recola\ and via \openloops, but
 have compiled them with different \fortran\ compilers.
 
 %%%%%
 
 \subsection{NLO cross sections}
 An NLO computation can be switched on in \sindarin\ with
 \begin{code}
   process proc_nlo = in1, in2 => out1, ..., outN { nlo_calculation = <components> },
 \end{code}
 where the \ttt{nlo\_calculation} can be followed by a list of strings
 specifying the desired NLO-components to be integrated, i.e.
 \ttt{born}, \ttt{real}, \ttt{virtual}, \ttt{dglap}, (for hadron
 collisions) or \ttt{mismatch} (for the soft mismatch in
 resonance-aware computations) and \ttt{full}. The \ttt{full} option
 switches on all components and is required if the total NLO result is
 desired. For example, specifying
 \begin{code}
   nlo_calculation = born, virtual
 \end{code}
 will result in the computation of the Born and virtual component.
 
 The integration can be carried out in two different modes: Combined
 and separate integration.  In the separate integration mode, each
 component is integrated individually, allowing for a good overview of
 their contributions to the total cross section and a fine tuned
 control over the iterations in each component.  In the combined
 integration mode, all components are added up during integration so that
 the sum of them is evaluated.  Here, only one integration will be
 displayed.  The default method is the separate integration.
 
 The convergence of the integration can crucially be influenced by the
 presence of resonances.  A better convergence is in this case achieved
 activating the resonance-aware FKS subtraction,
 \begin{code}
   $fks_mapping_type = "resonances".
 \end{code}
 This mode comes with an additional integration component, the
 so-called soft mismatch.
 
 Note that you can modify the number of iterations in each component with
 the multipliers:
 \begin{itemize}
   \item \ttt{mult\_call\_real} multiplies the number of calls to be used
     in the integration of the real component. A reasonable choice is
     \ttt{10.0} as the real phase-space is more complicated than the Born
     but the matrix elements evaluate faster than the virtuals.
   \item \ttt{mult\_call\_virt} multiplies the number of calls to be used
     in the integration of the virtual component. A reasonable choice is
     \ttt{0.5} to make sure that the fast Born component only contributes
     a negligible MC error compared to the real and virtual components.
   \item \ttt{mult\_call\_dglap} multiplies the number of calls to be used
     in the integration of the DGLAP component.
 \end{itemize}
 
 \subsection{Fixed-order NLO events}
 \label{ss:fixedorderNLOevents}
 Fixed-order NLO events can also be produced in three different modes:
 Combined weighted, combined unweighted and separated weighted.
 \begin{itemize}
   \item \textbf{Combined weighted}\\
     In the combined mode, one single integration grid is produced, from
     which events are generated with the total NLO weight. The
     corresponding event file contains $N$ events with born-like
     kinematics and weight equal to $\mathcal{B} + \mathcal{V} +
     \sum_{\alpha_r} \mathcal{C}_{\alpha_r}$, where $\mathcal{B}$ is the
     Born matrix element, $\mathcal{V}$ is the virtual matrix element and
     $\mathcal{C}_{\alpha_r}$ are the subtraction terms in each singular
     region. For resonance-aware processes, also the mismatch value is
     added. Each born-like event is followed by $N_{\text{phs}}$
     associated events with real kinematics, i.e. events where one
     additional QCD particle is present. The corresponding real
     matrix-elements $\mathcal{R}_\alpha$ form the weight of these events.
     $N_{\text{phs}}$ the number of distinct phase spaces. Two phase spaces
     are distinct if they share the same resonance history but have
     different emitters. So, two $\alpha_r$ can share the same phase
     space index.
 
     The combined event mode is activated by
     \begin{code}
       ?combined_nlo_integration = true
       ?unweighted = false
       ?fixed_order_nlo_events = true
     \end{code}
     Moreover, the process must be specified at next-to-leading-order in its
     definition using \ttt{nlo\_calculation = full}.  \whizard\ then
     proceeds as in the usual simulation mode. I.e. it first checks
     whether integration grids are already present and uses them if they
     fit. Otherwise, it starts an integration.
   \item \textbf{Combined unweighted}\\
     The unweighted combined events can be generated by using the
     \powheg\ mode, cf. also the next subsection, but disabling the
     additional radiation and Sudakov factors with the
     \ttt{?powheg\_disable\_sudakov} switch:
     \begin{code}
       ?combined_nlo_integration = true
       ?powheg_matching = true
       ?powheg_disable_sudakov = true
     \end{code}
     This will produce events with Born kinematics and unit weights (as
     \ttt{?unweighted} is \ttt{true} by default).  The events are
     unweighted by using $\mathcal{B} + \mathcal{V} + \sum_{\alpha_r}
     (\mathcal{C}_{\alpha_r} + \mathcal{R}_{\alpha_r})$.  Of course, this
     only works when these weights are positive over the full
     phase-space, which is not guaranteed for all scales and regions at
     NLO.  However, for many processes perturbation theory works nicely
     and this is not an issue.
 
   \item \textbf{Separate weighted}\\
     In the separate mode, grids and events are generated for each
     individual component of the NLO process. This method is preferable
     for complicated processes, since it allows to individually tune each
     grid generation. Moreover, the grid generation is then trivially
     parallelized.  The event files either contain only Born
     kinematics with weight $\mathcal{B}$ or $\mathcal{V}$ (and mismatch
     in case of a resonance-aware process) or mixed Born and real
     kinematics for the real component like in the combined mode.
     However, the Born events have only the weight $\sum_{\alpha_r}
     \mathcal{C}_{\alpha_r}$ in this case.
 
     The separate event mode is activated by
     \begin{code}
       ?unweighted = false
       ?negative_weights = true
       ?fixed_order_nlo_events = true
     \end{code}
     Note that negative weights have to be switched on because, in contrast
     to the combined mode, the total cross sections of the individual
     components can be negative.
 
     Also, the desired component has to appear in the process NLO
     specification, e.g. using \ttt{nlo\_calculation = real}.
 \end{itemize}
 Weighted fixed-order NLO events are supported by any output format that
 supports weights like the \ttt{HepMC} format and unweighted NLO events
 work with any format. The output can either be written to disk or put
 into a FIFO to interface it to an analysis program without writing
 events to file.
 
 The weights in the real event output, both in the combined and separate
 weighted mode, are divided by a factor $N_{\text{phs}} + 1$. This
 is to account for the fact that we artificially increase the number of
 events in the output file.  Thus, the sum of all event weights correctly
 reproduces the total cross section.
 
 \subsection{\powheg\ matching}
 To match the NLO computation with a parton shower, \whizard\ supports
 the  \powheg\ matching.  It generates a distribution according to
 \begin{align}
   \label{eq:powheg}
   \text{d}\sigma &= \text{d}\Phi_n \,{\bar{B}_{\text{s}}}\,\biggl(
   {\Delta_{\text{s}}}(p_T^{\text{min}}\bigr) +
   \text{d}\Phi_{\text{rad}}\,{\Delta_{\text{s}}}(k_{\text{T}}(\Phi_{\text{rad}})\bigr)
   {\frac{R_{\text{s}}}B}\biggr) \quad \text{where} \\
   {\bar{B}_{\text{s}}} &= {B} + {\mathcal{V}} + \text{d}\Phi_{\text{rad}}\,
     {\mathcal{R}_{\text{s}}} \quad \text{and} \\
   {\Delta_{\text{s}}}(p_T) &= \exp\left[- \int{\text{d}\Phi_{\text{rad}}}
    {\frac{R_{\text{s}}}{B}}\; \theta\left(k_T^2(\Phi_{\text{rad}}) -
    p_T^2\right)\right]\;.
 \end{align}
 The subscript s refers to the singular part of the real component, cf.
 to the next subsection.  Eq.~\eqref{eq:powheg} produces either no or one
 additional emission.  These events can then either be analyzed directly
 or passed on to the parton shower\footnote{E.g. \pythiaeight\ has
 explicit examples for \powheg\ input, see also
 \url{http://home.thep.lu.se/Pythia/pythia82html/POWHEGMerging.html}.}
 for the full simulation.  You activate this with
 \begin{code}
   ?fixed_order_nlo_events = false
   ?combined_nlo_integration = true
   ?powheg_matching = true
 \end{code}
 The $p_T^{\text{min}}$ of Eq.~\eqref{eq:powheg} can be set with
 \ttt{powheg\_pt\_min}.  It sets the minimal scale for the \powheg\
 evolution and should be of order 1 GeV and set accordingly in the
 interfaced shower.  The maximal scale is currently given by \ttt{sqrts}
 but should in the future be changeable with \ttt{powheg\_pt\_min}.
 
 Note that the \powheg\ event generation needs an additional grid for
 efficient event generation that is automatically generated during
 integration.  Further options that steer the efficiency of this grid are
 \ttt{powheg\_grid\_size\_xi} and \ttt{powheg\_grid\_size\_y}.
 
 \subsection{Separation of finite and singular contributions}
 
 For both the pure NLO computations as well as the \powheg\ event
 generation, \whizard\ supports the partitioning of the real into finite
 and singular contributions with the flag
 \begin{code}
   ?nlo_use_real_partition = true
 \end{code}
 The finite contributions, which by definition should not contain soft or
 collinear emissions, will then integrate like a ordinary LO integration
 with one additional particle.  Similarly, the event generation will
 produce only real events without subtraction terms with Born kinematics
 for this additional finite component.  The \powheg\ event generation
 will also only use the singular parts.
 
 The current implementation uses the following parametrization
 \begin{align}
   R                 &= R_{\text{fin}} + R_{\text{sing}} \;,\\
   R_{\text{sing}}     &= R F(\Phi_{n+1}) \;,\\
   R_{\text{fin}}      &= R (1-F(\Phi_{n+1})) \;,\\
   F(\Phi_{n+1})     &=
   \begin{cases}
     1 & \text{if} \quad\exists\,(i,j)\in\mathcal{P}_{\text{FKS}}\quad \text{with} \quad
       \sqrt{(p_i+p_j)^2} < h + m_i + m_j  \\
     0 & \text{else}
   \end{cases} \;.
 \end{align}
 Thus, a point is {singular ($F=1$)}, if {any} of the {FKS tuples}
 forms an {invariant mass} that is {smaller than the hardness scale
 $h$}. This parameter is controlled in \sindarin\ with
 \ttt{real\_partition\_scale}.
 This simplifies in {massless case} to
 \begin{align}
   F(\Phi_{n+1}) =
   \begin{cases}
     1 & \text{if} \;\exists\,(i,j)\in\mathcal{P}_{\text{FKS}}\quad \text{with} \quad
       2 E_i E_j (1-\cos\theta_{ij}) < h^2  \\
     0 & \text{else}
   \end{cases} \;.
 \end{align}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{Random number generators}
 \label{chap:rng}
 
 \section{General remarks}
 \label{sec:rng}
 
 The random number generators (RNG) are one of the crucialer points of Monte
 Carlo calculations, hence, giving those their ``randomness''. A decent
 multipurpose random generator covers
 \begin{itemize}
 \item reproducibility
 \item large period
 \item fast generation
 \item independence
 \end{itemize}
 of the random numbers. Therefore, special care is taken for the choice of the
 RNGs in \whizard{}. It is stated that \whizard{} utilizes \textit{pseudo}-RNGs,
 which are based on one (or more) recursive algorithm(s) and start-seed(s) to have
 reproducible sequences of numbers. In contrast, a genuine random generator relies
 on physical processes.
 
 \whizard\ ships with two completely different random number generators which can be
 selected by setting the \sindarin\ option
 \begin{code}
   $rng_method = "rng_tao"
 \end{code}
 Although, \whizard{} sets a default seed, it is adviced to use a different one
 \begin{code}
   seed = 175368842
 \end{code}
 note that some RNGs do not allow certain seed values (e.g. zero seed).
 
 \section{The TAO Random Number Generator}
 \label{sec:tao}
 
 The TAO (``The Art Of'') random number generator is a lagged Fibonacci
 generator based upon (signed) 32-bit integer arithmetic and was proposed by
 Donald E. Knuth and is implemented in the \vamp\ package.
 The TAO random number generator is the default RNG of \whizard{}, but can additionally
 be set as \sindarin\ option
 \begin{code}
   $rng_method = rng_tao
 \end{code}
 
 The TAO random number generators is a subtractive lagged Fibonacci generator
 \begin{equation*}
   x_{j} = \left( x_{j-k} - x_{j-L} \right) \mod 2^{30}
 \end{equation*}
 with lags $k = 100$ and $l = 37$ and period length $\rho = 2^{30} - 2$.
 
 \section{The RNGStream Generator}
 \label{sec:rngstream}
 
 The RNGStream \cite{L_Ecuyer:2002} was originally implemented in \cpp\ with
 floating point arithmetic and has been ported to \fortranOThree{}. The RNGstream
 can be selected by the \sindarin\ option
 \begin{code}
   $rng_method = "rng_stream"
 \end{code}
 
 The RNGstream supports multiple independent streams and substreams of random
 numbers which can be directly accessed.
 
 The main advantage of the RNGStream lies in the domain of parallelization where
 different worker have to access different parts of the random number stream to
 ensure numerical reproducibility. The RNGstream provides exactly this property with its
 (sub)stream-driven model.
 
 Unfortunately, the RNGStream can only be used in combination with \vamptwo{}.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{Integration Methods}
 
 \section{The Monte-Carlo integration routine: \ttt{VAMP}}
 \label{sec:vamp}
 
 \vamp\ \cite{Ohl:1998jn}
 is a multichannel extension of the \vegas\ \cite{Lepage:1980dq}
 algorithm. For all possible singularities in the integrand, suitable
 maps and integration channels are chosen which are then weighted and
 superimposed to build the phase space parameterization. Both grids and
 weights are modified in the adaption phase of the integration.
 
 The multichannel integration algorithm is implemented as a
 \fortranNinetyFive\ library with the task of mapping out the integrand
 and finding suitable parameterizations being completely delegated to
 the calling program (\whizard\ core in this case). This makes the
 actual \vamp\ library completely agnostic of the model under
 consideration.
 
 \section{The next generation integrator: \ttt{VAMP2}}
 \label{sec:vamp2}
 
 \vamptwo\ is a modern implementation of the integrator package \vamp\ written
 in \fortranOThree\, providing the same features. The backbone integrator is
 still \vegas\ \cite{Lepage:1980dq}, although implemented differently as in
 \vamp{}.
 
 The main advantage over \vamp\ is the overall faster integration due to the usage
 of \fortranOThree{}, the possible usage of different random number generators
 and the complete parallelization of \vegas\ and the multichannel integration.
 
 \vamptwo{} can be set by the \sindarin{} option
 \begin{code}
   $integration_method = "vamp2"
 \end{code}
 
 It is said that the generated grids between \vamp{} and \vamptwo{} are
 incompatible.
 
 \subsection{Multichannel integration}
 \label{sec:multi-channel}
 
 The usual matrix elements do not factorise with respect to their integration
 variables, thus making an direct integration ansatz with VEGAS
 unfavorable.\footnote{One prerequisite for the VEGAS algorithm is that the
   integral factorises, and such produces only the best results for those.} Instead, we
 apply the multichannel ansatz and let VEGAS integrate each channel in a
 factorising mapping.
 
 The different structures of the matrix element are separated by a partition of
 unity and the respective mappings, such that each structure factorise at least
 once. We define the mappings $\phi_i : U \mapsto \Omega$, where $U$ is the unit
 hypercube and $\Omega$ the physical phase space. We refer to each mapping as a
 \textit{channel}. Each channel then gives rise to a probability density $g_i : U
 \mapsto [0, \infty)$, normalised to unity
 \begin{equation*}
   \int_0^1 g_i(\phi_i^{-1}(p)) \left| \frac{\partial \phi_i^{-1}}{\partial p} \right| \mathrm{d}\mu(p) = 1, \quad g_i(\phi_i^{-1}(p)) \geq 0,
 \end{equation*}
 written for a phase space point $p$ using the mapping $\phi_i$.
 The \textit{a-priori} channel weights $\alpha_i$ are defined as partition of
 unity by $\sum_{i\in I} \alpha_i = 1$ and $0 \leq \alpha_i \leq 1$. The overall
 probability density $g$ of a random sample is then obtained by
 \begin{equation*}
   g(p) = \sum_{i \in I} \alpha_i g_i(\phi_i^{-1}(p)) \left| \frac{\partial \phi_i^{-1}}{\partial p} \right|,
 \end{equation*}
 which is also a non-negative and normalized probability density.
 
 We reformulate the integral
 \begin{equation*}
   I(f) = \sum_{i \in I} \alpha_i \int_\Omega g_i(\phi_i^{-1}(p)) \left| \frac{\partial \phi_i^{-1}}{\partial p} \right| \frac{f(p)}{g(p)} \mathrm{d}\mu(p).
 \end{equation*}
 The actual integration of each channel is then done by VEGAS, which shapes the $g_i$.
 
 \subsection{VEGAS}
 \label{sec:vegas}
 
 VEGAS is an adaptive and iterative Monte Carlo algorithm for integration using
 importance sampling. After each iteration, VEGAS adapts the probability density
 $g_i$ using information collected while sampling. For independent
 integration variables, the probability density factorises $g_i = \prod_{j =
   1}^{d} g_{i,j}$ for each integration axis and each (independent) $g_{i,j}$ is
 defined by a normalised step function
 \begin{equation*}
   g_{i,j} (x_j) = \frac{1}{N\Delta x_{j,k}}, \quad x_{j,k} - \Delta x_{j,k} \leq x_{j} < x_{j,k},
 \end{equation*}
 where the steps are $0 = x_{j, 0} < \cdots < x_{j,k} < \cdots < x_{j,N} = 1$ for
 each dimension $j$.
 The algorithm randomly selects for each dimension a bin and a position inside
 the bin and calculates the respective $g_{i,j}$.
 
 \subsection{Channel equivalences}
 \label{sec:equivalences}
 
 The automated mulitchannel phasespace configuration can lead to a surplus of
 degrees of freedom, e.g. for a highly complex process with a large number of
 channels (VBS). In order to marginalize the redundant degrees of freedom of
 phasespace configuration, the adaptation distribution of the grids are aligned in accordance to their
 phasespace relation, hence the binning of the grids is equialized. These equivalences are activated by
 default for \vamp{} and \vamptwo{}, but can be steered by:
 
 \begin{code}
   ?use_vamp_equivalences = true
 \end{code}
 
 Be aware, that the usage of equivalences are currently only possible for LO
 processes.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{Phase space parameterizations}
 
 \section{General remarks}
 
 \whizard\ as a default performs an adaptive multi-channel Monte-Carlo
 integration. Besides its default phase space algorithm, \ttt{wood}, to
 be detailed in Sec.~\ref{sec:wood}, \whizard\ contains a phase space
 method \ttt{phs\_none} which is a dummy method that is intended for
 setups of processes where no phase space integration is needed, but
 the program flow needs a (dummy) integrator for internal
 consistency. Then, for testing purposes, there is a single-channel
 phase space integrator, \ttt{phs\_single}. From version 2.6.0 of
 \whizard\ on, there is also a second implementation of the \ttt{wood}
 phase space algorithm, called \ttt{fast\_wood},
 cf. Sec.~\ref{sec:fast_wood}, whose implementation differs technically
 and which therefore solves certain technical flaws of the \ttt{wood}
 implementation.
 Additionally, \whizard\ supports single-channel, flat phase-space using RAMBO
 (on diet).
 
 %%%
 
 \section{The flat method: \ttt{rambo}}
 \label{sec:rambo}
 
 The \ttt{RAMBO} algorithm produces a flat phase-space with constant volume for
 massless particles. \ttt{RAMBO} was originally published in
 \cite{Kleiss:1985gy}. We use the slim version, called \ttt{RAMBO} on diet,
 published in \cite{Platzer:2013esa}.
 The overall weighting efficiency of the algorithm is unity for massless
 final-state particles. For the massive case, the weighting efficiency of unity will
 decrease rendering the algorithm less efficient. But in most cases, the
 invariants are in regions of phase space where they are much larger than the
 masses of the final-state particles.
 
 We provide the \ttt{RAMBO} mainly for cross checking our
 implementation and do not recommend it for real world application,
 even though it can be used as one.  The \ttt{RAMBO} method becomes
 useful as a fall-back option if the standard algorithm fails for
 physical reasons, see, e.g., Sec.~\ref{sec:ps_anomalous}.
 
 %%%
 
 \section{The default method: \ttt{wood}}
 \label{sec:wood}
 
 The \ttt{wood} algorithm classifies different phase space channels
 according to their importance for a full scattering or decay process
 following heuristic rules. For that purpose, \whizard\ investigates
 the kinematics of the different channels depending on the total
 center-of-mass energy (or the mass of the decaying particle) and the
 masses of the final-state particles.
 
 The \ttt{wood} phase space inherits its name from the naming schemes
 of structures of increasing complexities, namely trees, forests and
 groves. Simply stated, a phase-space forest is a collection of
 phase-space trees. A phase-space tree is a parameterization for a
 valid channel in the multi-channel adaptive integration, and each
 variable in the a tree corresponds to an integration dimension,
 defined by an appropriate mapping of the $(0,1)$ interval of the unit
 hypercube to the allowed range of the corresponding integration
 variable. The whole set of these phase-space trees, collected in a
 phase-space forest object hence contains all parameterizations of the
 phase space that \whizard\ will use for a single hard process. Note
 that processes might contain flavor sums of particles in the final
 state. As \whizard\ will use the same phase space parameterization for
 all channels for this set of subprocesses, all particles in those
 flavor sums have to have the same mass. E.g. in the definition of a
 "light" jet consisting of the first five quarks and antiquarks,
 \begin{code}
   alias jet = u:d:s:c:b:U:D:S:C:B
 \end{code}
 all quarks including strange, charm and bottom have to be massless for
 the phase-space integration. \whizard\ can treat processes with
 subprocesses having final-state particles with different masses in an
 "additive" way, where each subprocess will become a distinct component
 of the whole process. Each process component will get its own
 phase-space parameterization, such that they can allow for different
 masses. E.g. in a 4-flavor scheme for massless $u,d,s,c$ quarks one
 can write
 \begin{code}
   alias jet = u:d:s:c:U:D:S:C
   process eeqq = e1, E1 => (jet, jet) + (b, B)
 \end{code}
 In that case, the parameterizations will be for massless final state
 quarks for the first subprocess, and for massive $b$ quarks for the
 second subprocess. In general, for high-energy lepton colliders, the
 difference would not matter much, but performing the integration
 e.g. for $\sqrt{s} = 11$ GeV, the difference will be
 tremendous. \whizard\ avoids inconsistent phase-space
 parameterizations in that way.
 
 As a multi-particle process will contain hundred or thousands of
 different channels, the different integration channels (trees) are
 grouped into so called {\em groves}. All channels/trees in the same
 grove share a common weight for the phase-space integration, following
 the assumption that they are related by some approximate symmetry. The
 \vamp\ adaptive multi-channel integrator (cf. Sec.~\ref{sec:vamp})
 allows for equivalences between different integration channels. This
 means that trees/channels that are related by an exact symmetry are
 connected by an array of these equivalences.
 
 The phase-space setup, i.e. the detailed structure of trees and
 forests, are written by \whizard\ into a phase-space file that has the
 same name as the corresponding process (or process component) with the
 suffix \ttt{.phs}. For the \ttt{wood} phase-space method this file is
 written by a \fortran\ module which constructs a similar tree-like
 structure as the directed acyclical graphs (DAGs) in the
 \oMega\ matrix element generator but in a less efficient way.
 
 In some very rare cases with externally generated models
 (cf. Chapter~\ref{chap:extmodels}) the phase-space generation has been
 reported to fail as \whizard\ could not find a valid phase-space
 channel. Such pathological cases cannot occur for the hard-coded model
 implementations inside \whizard. They can only happen if there are in
 principle two different Feynman diagrams contributing to the same
 phase-space channel and \whizard\ considers the second one as
 extremely subleading (and would hence drop it). If for some reason
 however the first Feynman diagram is then absent, no phase-space
 channel could be found. This problem cannot occur with the
 \ttt{fast\_wood} implementation discussed in the next section,
 cf.~\ref{sec:fast_wood}.
 
 The \ttt{wood} algorithms orders the different groves of phase-space
 channels according to a heuristic importance depending on the
 kinematic properties of the different phase-space channels in the
 groves. A phase-space (\ttt{.phs}) file looks typically like this:
 \begin{code}
  process sm_i1
 
 ! List of subprocesses with particle bincodes:
 !  8  4      1   2
 ! e+ e- => mu+ mu-
 !  8  4      1   2
 
    md5sum_process    = "1B3B7A30C24664A73D3D027382CFB4EF"
    md5sum_model_par  = "7656C90A0B2C4325AD911301DACF50EB"
    md5sum_phs_config = "6F72D447E8960F50FDE4AE590AD7044B"
    sqrts         =  1.000000000000E+02
    m_threshold_s =  5.000000000000E+01
    m_threshold_t =  1.000000000000E+02
    off_shell = 2
    t_channel = 6
    keep_nonresonant = T
 
  ! Multiplicity = 2, no resonances,  0 logs,  0 off-shell,  s-channel graph
  grove #1
  ! Channel #1
    tree  3
 
  ! Multiplicity = 1, 1 resonance,   0 logs,  0 off-shell,  s-channel graph
  grove #2
  ! Channel #2
    tree  3
    map   3 s_channel      23 ! Z
 \end{code}
 The first line contains the process name, followed by a list of
 subprocesses with the external particles and their binary codes. Then
 there are three lines of MD5 check sums, used for consistency
 checks. \whizard\ (unless told otherwise) will check for the existence
 of a phase-space file, and if the check sum matches, it will reuse the
 existing file and not generate it again. Next, there are several
 kinematic parameters, namely the center-of-mass energy of the process,
 \ttt{sqrts}, and two mass thresholds, \ttt{m\_threshold\_s} and
 \ttt{m\_threshold\_t}. The latter two are kinematical thresholds,
 below which \whizard\ will consider $s$-channel and $t$-channel-like
 kinematic configurations as effectively massless, respectively. The
 default values shown in the example have turned out to be optimal
 values for Standard Model particles. The two integers \ttt{off\_shell}
 and \ttt{t\_channel} give the number of off-shell lines and of
 $t$-channel lines that \whizard\ will allow for finding valid
 phase-space channels, respectively. This neglects extremley multi-peripheral
 background-like diagram constellations which are very subdominamnt
 compared to resonant signal processes. The final flag specifies
 whether \whizard\ will keep non-resonant phase-space channels
 (default), or whether it will focus only on resonant situations.
 
 After this header, there is a list of all groves, i.e. collections of
 phase-space channels which are connected by quasi-symmetries, together
 with the corresponding multiplicity of subchannels in that
 grove. In the phase-space file behind the multiplicity,
 \whizard\ denotes the number of (massive) resonances, logarithmcally
 enhanced kinematics (e.g. collinear regions), and number of off-shell
 lines, respectively. The final entry in the grove header notifies
 whether the diagrams in that grove have $s$-channel topologies, or
 count the number of corresponding $t$-channel lines.
 
 Another example is shown here,
 \begin{code}
  ! Multiplicity = 3, no resonances,  2 logs,  0 off-shell,  1 t-channel line
  grove #1
  ! Channel #1
    tree  3 12
    map   3 infrared       22 ! A
    map  12 t_channel       2 ! u
  ! Channel #2
    tree  3 11
    map   3 infrared       22 ! A
    map  11 t_channel       2 ! u
  ! Channel #3
    tree  3 20
    map   3 infrared       22 ! A
    map  20 t_channel       2 ! u
  ! Channel #4
    tree  3 19
    map   3 infrared       22 ! A
    map  19 t_channel       2 ! u
 \end{code}
 where \whizard\ notifies in different situations a photon exchange as
 \ttt{infrared}. So it detects a possible infrared singularity where a
 particle can become arbitrarily soft. Such a situation can tell the
 user that there might be a cut necessary in order to get a meaningful
 integration result.
 
 The phase-space setup that is generated and used by the \ttt{wood}
 phase-space method can be visualized using the \sindarin\ option
 \begin{code}
   ?vis_channels = true
 \end{code}
 
 The \ttt{wood} phase-space method can be invoked with the
 \sindarin\ command
 \begin{code}
   $phs_method = "wood"
 \end{code}
 Note that this line is unnecessary, as \ttt{wood} is the default
 phase-space method of \whizard.
 
 %%%%%
 
 \section{A new method: \ttt{fast\_wood}}
 \label{sec:fast_wood}
 
 This method (which is available from version 2.6.0 on) is an
 alternative implementation of the \ttt{wood} phase-space algorithm. It
 uses the recursive structures inside the \oMega\ matrix element
 generator to generate all the structures needed for the different
 phase-space channels. In that way, it can avoid some of the
 bottlenecks of the \ttt{wood} \fortran\ implementation of the
 algorithm. On the other hand, it is only available if the
 \oMega\ matrix element generator has been enabled (which is the
 default for \whizard). The \ttt{fast\_wood} method is then invoked via
 \begin{code}
   ?omega_write_phs_output = true
   $phs_method = "fast_wood"
 \end{code}
 The first option is necessary in order to tell \oMega\ to write out
 the output needed for the \ttt{fast\_wood} parser in order to generate
 the phase-space file. This is not enabled by default in order not to
 generate unnecessary files in case the default method \ttt{wood} is
 used.
 
 So the \ttt{fast\_wood} implementation of the \ttt{wood} phase-space
 algorithm parses the tree-like represenation of the recursive set of
 one-particle off-shell wave functions that make up the whole amplitude
 inside \oMega\ in the form of a directed acyclical graph (DAG) in
 order to generate the phase-space (\ttt{.phs}) file
 (cf. Sec.~\ref{sec:wood}). In that way, the algorithm makes sure that
 only phase-space channels are generated for which there are indeed
 (sub)amplitudes in the matrix elements, and this also allows to
 exclude vetoed channels due to restrictions imposed on the matrix
 elements from the phase-space setup (cf. next
 Sec.~\ref{sec:ps_restrictions}).
 
 %%%%%
 
 \section{Phase space respecting restrictions on subdiagrams}
 \label{sec:ps_restrictions}
 
 The \fortran\ implementation of the \ttt{wood} phase-space does not
 know anything about possible restrictions that maybe imposed on the
 \oMega\ matrix elements, cf. Sec.~\ref{sec:process options}.
 Consequently, the \ttt{wood} phase space also generates phase-space
 channels that might be absent when restrictions are imposed. This is
 not a principal problem, as in the adaptation of the phase-space
 channels \whizard's integrator \vamp\ will recognize that there is
 zero weight in that channel and will drop the channel (stop sampling
 in that channel) after some iterations. However, this is a waste of
 ressources as it is in principle known that this channel is
 absent. Using the \ttt{fast\_wood} phase-space algorithm
 (cf. Sec.~\ref{sec:fast_wood} will take restrictions into account, as
 \oMega\ will not generate trees for channels that are removed with the
 restrictions command. So it advisable for the user in the case of very
 complicated processes with restrictions to use the \ttt{fast\_wood}
 phase-space method to make \whizard\ generation and integration of the
 phase space less cumbersome.
 
 %%%%%
 
 \section{Phase space for processes forbidden at tree level}
 \label{sec:ps_anomalous}
 
 The phase-space generators \ttt{wood} and \ttt{fast\_wood} are
 intended for tree-level processes with their typical patterns of
 singularities, which can be read off from Feynman graphs.  They can
 and should be used for loop-induced or for externally provided matrix
 elements as long as \whizard\ does not provide a dedicated phase-space
 module.
 
 Some scattering processes do not occur at tree level but become
 allowed if loop effects are included in the calculation.  A simple
 example is the elastic QED process
 \begin{displaymath}
   A\quad A \longrightarrow A\quad A
 \end{displaymath}
 which is mediated by a fermion loop.  Similarly, certain applications
 provide externally provided or hand-taylored matrix-element code that
 replaces the standard \oMega\ code.
 
 Currently, \whizard's phase-space parameterization is nevertheless
 tied to the \oMega\ generator, so for tree-level forbidden processes
 the phase-space construction process will fail.
 
 There are two possible solutions for this problem:
 \begin{enumerate}
 \item
   It is possible to provide the phase-space parameterization
   information externally, by supplying an appropriately formatted
   \ttt{.phs} file, bypassing the automatic algorithm.  Assuming that
   this phase-space file has been named \ttt{my\_phase\_space.phs}, the
   \sindarin\ code should contain the following: 
   \begin{code}
     ?rebuild_phase_space = false
     $phs_file = "my_phase_space.phs"
   \end{code}
   Regarding the contents of this file, we recommend to generate an
   appropriate \ttt{.phs} for a similar setup, using the standard
   algorithm.  The generated file can serve as a template, which can be
   adapted to the particular case.  
 
   In detail, the \ttt{.phs} file consists of entries that specify the
   process, then a standard header which contains MD5 sums and such --
   these variables must be present but their values are irrelevant for
   the present case --, and finally at least one \ttt{grove} with
   \ttt{tree} entries that specify the parameterization.  Individual
   parameterizations are built from the final-state and initial-state
   momenta (in this order) which we label in binary form as
   $1,2,4,8,\dots$.  The actual tree consists of iterative fusions of
   those external lines.  Each fusion is indicated by the number that
   results from adding the binary codes of the external momenta that
   contribute to it.
 
   For instance, a valid phase-space tree for the process $AA\to AA$ is
   given by the simple entry
   \begin{code}
     tree 3
   \end{code}
   which indicates that the final-state momenta $1$ and $2$ are
   combined to a fusion $1+2=3$.  The setup is identical to a process
   such as $e^+e^-\to\mu^+\mu^-$ below the $Z$ threshold.  Hence, we
   can take the \ttt{.phs} file for the latter process, replace the
   process tag, and use it as an external phase-space file.
 \item
   For realistic applications of \whizard\ together with one-loop
   matrix-element providers, the actual number of final-state particles may be
   rather small, say $2,3,4$.  Furthermore, one-loop processes which are
   forbidden at tree level do not contain soft or collinear
   singularities.  In this situation, the \ttt{RAMBO}
   phase-space integration method, cf.\ Sec.~\ref{sec:rambo} is a
   viable alternative which does not suffer from the problem.
 \end{enumerate}
 
 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{Methods for Hard Interactions}
 \label{chap:hardint}
 
 The hard interaction process is the core of any physics simulation
 within an MC event generator. One tries to describe the dominant
 particle interaction in the physics process of interest at a given
 order in perturbation theory, thereby making use of field-theoretic
 factorization theorems, especially for QCD, in order to separate
 non-perturbative physics like parton distribution functions (PDFs) or
 fragmentation functions from the perturbative part. Still, it is in
 many cases not possible to describe the perturbative part completely
 by means of fixed-order hard matrix elements: in soft and/or collinear
 regions of phase space, multiple emission of gluons and quarks (in
 general QCD jets) and photons necessitates a resummation, as large
 logarithms accompany the perturbative coupling constants and render
 fixed-order perturbation theory unreliable. The resummation of these
 large logarithms can be done analytically or (semi-)numerically,
 however, usually only for very inclusive quantities. At the level of
 exclusive events, these phase space regions are the realm of (QCD and
 also QED) parton showers that approximate multi-leg matrix elements
 from the hard perturbative into to the soft-/collinear regime.
 
 The hard matrix elements are then the core building blocks of the
 physics description inside the MC event generator. \whizard\ generates
 these hard matrix elements at tree-level (or sometimes for
 loop-induced processes using effective operators as insertions) as
 leading-order processes. This is done by the \oMega\ subpackage that
 is automatically called by \whizard. Besides these physical matrix
 elements, there exist a couple of methods to generate dummy matrix
 elements for testing purposes, or for generating beam profiles and
 using them with externally linked special matrix elements.
 
 Especially for one-loop processes (next-to-leading order for
 tree-allowed processes or leading-order for loop-induced processes),
 \whizard\ allows to use matrix elements from external providers, so
 called OLP programs (one-loop providers). Of course, all of these
 external packages can also generate tree-level matrix elements, which
 can then be used as well in \whizard.
 
 We start the discussion with the two different options for test matrix
 elements, internal test matrix elements with no generated compiled code
 in Sec.~\ref{sec:test_me} and so called template matrix elements with
 actual \fortran\ code that is compiled and linked, and can also be
 modified by the user in Sec.~\ref{sec:template_me}. Then, we move to
 the main matrix element method by the matrix element generator
 \oMega\ in Sec.~\ref{sec:omega_me}. Matrix elements from the external
 matrix element generators are discussed in the order of which
 interfaces for the external tools have been implemented: \gosam\ in
 Sec.~\ref{sec:gosam_me}, \openloops\ in Sec.~\ref{sec:openloops_me},
 and \recola\ in Sec.~\ref{sec:recola_me}.
 
 %%%%%
 
 \section{Internal test matrix elements}
 \label{sec:test_me}
 
 This method is merely for internal consistency checks inside \whizard,
 and is not really intended to be utilized by the user. The method is
 invoked by
 \begin{code}
   $method = "unit_test"
 \end{code}
 This particular method is only applicable for the internal test model
 \ttt{Test.mdl}, which just contains a Higgs boson and a top
 quark. Technically, it will also works within model specifications
 for the Standard Model, or the Minimal Supersymmetric Standard Model
 (MSSM), or all models which contain particles named as \ttt{H} and
 \ttt{t} with PDG codes 25 and 6, respectively. So, the models
 \ttt{QED} and {QCD} will not work. Irrespective of what is given in
 the \sindarin\ file as a scattering input process, \whizard\ will
 always take the process
 \begin{code}
   model = SM
   process <proc_name>= H, H => H, H
 \end{code}
 or for the test model:
 \begin{code}
   model = Test
   process <proc_name>= s, s => s, s
 \end{code}
 as corresponding process. (This is the same process, just with
 differing nomenclature in the different models). No matrix element
 code is generated and compiled, the matrix element is completely
 internal, included in the \whizard\ executable (or library), with a
 unit value for the squared amplitude. The integration will always be
 performed for this particularly process, even if the user provides a
 different process for that method. Hence, the result will always be
 the volume of the relativistic two-particle phase space. The only two
 parameters that influence the result are the collider energy,
 \ttt{sqrts}, and the mass of the Higgs particle with PDG code 25 (this
 mass parameter can be changed in the model \ttt{Test} as \ttt{ms},
 while it would be \ttt{mH} in the Standard Model \ttt{SM}.
 
 It is also possible to use a test matrix element, again internal, for
 decay processes, where again \whizard\ will take a predefined process:
 \begin{code}
   model = SM
   process <proc_name> = H => t, tbar
 \end{code}
 in the \ttt{SM} model or
 \begin{code}
   model = Test
   process <proc_name> = s => f, fbar
 \end{code}
 Again, this is the same process with PDG codes $25 \to 6 \; -6$ in the
 corresponding models. Note that in the model \ttt{SM} the mass of the
 quark is set via the variable \ttt{mtop}, while it is \ttt{mf} in the
 model \ttt{Test}.
 
 Besides the fact that the user always gets a fixed process and cannot
 modify any matrix element code by hand, one can do all things as for a
 normal process like generating events, different weights, testing
 rebuild flags, using different setups and reweight events
 accordingly. Also factorized processes with production and decay can
 be tested that way.
 
 In order to avoid confusion, it is highly recommended to use this
 method \ttt{unit\_test} only with the test model setup, model
 \ttt{Test}.
 
 On the technical side, the method \ttt{unit\_test} does not produce a
 process library (at least not an externally linked one), and also not
 a makefile in order to modify any process files (which anyways do not
 exist for that method). Except for the logfiles and the phase space
 file, all files are internal.
 
 %%%%%
 
 \section{Template matrix elements}
 \label{sec:template_me}
 
 Much more versatile for the user than the previous matrix element
 method in~\ref{sec:test_me}, are two different methods with constant
 template matrix elements. These are written out as \fortran\ code by
 the \whizard\ main executable (or library), providing an interface
 that is (almost) identical to the matrix element code produced by the
 \oMega\ generator (cf. the next section,
 Sec.~\ref{sec:omega_me}. There are actually two different methods for
 that purpose, providing matrix elements with different normalizations:
 \begin{code}
   $method = "template"
 \end{code}
 generates matrix elements which give after integration over phase
 space exactly one. Of course, for multi-particle final states the
 integration can fluctuate numerically and could then give numbers that
 are only close to one but not exactly one. Furthermore, the
 normalization is not exact if any of the external particles have
 non-zero masses, or there are any cuts involved. But otherwise, the
 integral from \whizard\ should give unity irrespective of the number
 of final state particles.
 
 In contrast to this, the second method,
 \begin{code}
   $method = "template_unity"
 \end{code}
 gives a unit matrix elements, or rather a matrix element that contains
 helicity and color averaging factors for the initial state and the
 square root of the factorials of identical final state particles in
 the denominator. Hence, integration over the final state momentum
 configuration gives a cross section that corresponds to the volume of
 the $n$-particle final state phase space, divided by the corresponding
 flux factor, resulting in
 \begin{equation}
   \sigma(s, 2 \to 2,0) = \frac{3.8937966\cdot 10^{11}}{16\pi} \cdot
   \frac{1}{s \text{[GeV]}^2} \; \text{fb}
 \end{equation}
 for the massless case and
 \begin{equation}
   \sigma(s, 2 \to 2,m_i) = \frac{3.8937966\cdot 10^{11}}{16\pi} \cdot
   \sqrt{\frac{\lambda (s,m_3^2,m_4^2)}{\lambda (s,m_1^2,m_2^2)}}
   \cdot \frac{1}{s \text{[GeV]}^2} \; \text{fb}
 \end{equation}
 for the massive case. Here, $m_1$ and $m_2$ are the masses of the
 incoming, $m_3$ and $m_4$ the masses of the outgoing particles, and
 $\lambda(x,y,z) = x^2 + y^2 + z^2 - 2xy - 2xz - 2yz$.
 
 For the general massless case with no cuts, the integral should be
 exactly
 \begin{equation}
   \sigma(s, 2\to n, 0) = \frac{(2\pi)^4}{2 s}\Phi_n(s)
   = \frac{1}{16\pi s}\,\frac{\Phi_n(s)}{\Phi_2(s)},
 \end{equation}
 where the volume of the massless $n$-particle phase space is
 given by
 \begin{equation}\label{phi-n}
   \Phi_n(s) = \frac{1}{4(2\pi)^5} \left(\frac{s}{16\pi^2}\right)^{n-2}
   \frac{1}{(n-1)!(n-2)!}.
 \end{equation}
 For $n\neq2$ the phase space volume is dimensionful, so the
 units of the integral are $\fb\times\GeV^{2(n-2)}$. (Note that for
 physical matrix elements this is compensated by momentum factors from
 wave functions, propagators, vertices and possibly dimensionful
 coupling constants, but here the matrix element is just equal to
 unity.)
 
 Note that the phase-space integration for the \ttt{template} and
 \ttt{template\_unity} matrix element methods is organized in the same
 way as it would be for the real $2\to n$ process.  Since such a phase
 space parameterization is not optimized for the constant matrix
 element that is supplied instead, good convergence is not guaranteed.
 (Setting \ttt{?stratified = true} may be helpful here.)
 
 The possibility to call a dummy matrix element with this method allows
 to histogram spectra or structure functions: Choose a trivial process
 such as $uu\to dd$, select the \ttt{template\_unity} method, switch
 on structure functions for one (or both) beams, and generate events.
 The distribution of the final-state mass squared reflects the $x$
 dependence of the selected structure function.
 
 Furthermore, the constant in the source code of the unit matrix
 elements can be easily modified by the user with their \fortran\ code
 in order to study customized matrix elements. Just rerun
 \whizard\ with the \ttt{--recompile} option after the modification of
 the matrix element code.
 
 Both methods, \ttt{template} and \ttt{template\_unity} will also work
 even if no \ocaml\ compiler is found or used and consequently the
 \oMega\ matrix elemente generator (cf. Sec.~\ref{sec:omega_me} is
 disable. The methods produce a process library for their corresponding
 processes, and a makefile, by  which \whizard\ steers compilation and
 linking of the process source code.
 
 %%%%%
 
 \section{The O'Mega matrix elements}
 \label{sec:omega_me}
 
 \oMega\ is a subpackage of \whizard, written in \ocaml, which can
 produce matrix elements for a wide class of implemented physics models
 (cf. Sec.~\ref{sec:smandfriends} and \ref{sec:bsmmodels} for a list of
 all implemented physics models), and even almost arbitrary models when
 using external Lagrange level tools, cf. Chap.~\ref{chap:extmodels}.
 There are two different variants for matrix elements from \oMega:
 the first one is invoked as
 \begin{code}
   $method = "omega"
 \end{code}
 and is the default method for \whizard. It produces matrix element as
 \fortran\ code which is then compiled and linked. An alternative
 method, which for the moment is only available for the Standard Model
 and its variants as well models which are quite similar to the SM,
 e.g. the Two-Higgs doublet model or the Higgs-singlet extension. This
 method is taken when setting
 \begin{code}
   $method = "ovm"
 \end{code}
 The acronym \ttt{ovm} stands for \oMega\ Virtual Machine (OVM). The
 first (default) method (\ttt{omega}) of \oMega\ matrix elements
 produces \fortran\ code for the matrix elements,that is compiled by
 the same compiler with which \whizard\ has been compiled. The OVM
 method (\ttt{ovm}) generates an \ttt{ASCII} file with so called op
 code for operations. These are just numbers which tell what numerical
 operations are to be performed on momenta, wave functions and vertex
 expression in order to yield a complex number for the amplitude. The
 op codes are interpreted by the OVM in the same as a Java Virtual
 Machine. In both cases, a compiled \fortran\ is generated which for
 the \ttt{omega} method contains the full expression for the matrix
 element as \fortran\ code, while for the \ttt{ovm} method this is the
 driver file of the OVM. Hence, for the \ttt{ovm} method this file
 always has roughly the same size irrespective of the complexity of the
 process. For the \ttt{ovm} method, there will also be the \ttt{ASCII}
 file that contains the op codes, which has a name with an \ttt{.hbc}
 suffix: \ttt{<process\_name>.hbc}.
 
 For both \oMega\ methods, there will be a process library created as
 for the template matrix elements (cf. Sec.~\ref{sec:template_me})
 named \ttt{default\_lib.f90} which can be given a user-defined name
 using the \ttt{library = "<library>"} command. Again, for both methods
 \ttt{omega} and \ttt{ovm}, a makefile named
 \ttt{<library>\_lib.makefile} is generated by which \whizard\ steers
 compilation, linking and clean-up of the process sources. This
 makefile can handily be adapted by the user in case she or he wants to
 modify the source code for the process (in the case of the source code
 method).
 
 Note that \whizard's default ME method via \oMega\ allows the user to
 specify many different options either globally for all processes in
 the \sindarin, or locally for each process separately in curly
 brackets behind the corresponding process definition. Examples are
 \begin{itemize}
 \item
   Restrictions for the matrix elements like the exclusion of
   intermediate resonances, the appearance of specific vertices or
   coupling constants in the matrix elments. For more details on this
   cf. Sec.~\ref{subsec:restrictions}.
 \item
   Choice of a specific scheme for the width of massive intermediate
   resonances, whether to use constant width, widths only in
   $s$-channel like kinematics (this is the default), a fudged-width
   scheme or the complex-mass scheme. The latter is actually steered as
   a specific scheme of the underlying model and not with a specific
   \oMega\ command.
 \item
   Choice of the electroweak gauge for the amplitude. The default is
   the unitary gauge.
 \end{itemize}
 With the exception of the restrictions steered by the
 \ttt{\$restrictions = "<restriction>"} string expression, these options
 have to be set in their specific \oMega\ syntax verbatim via the
 string command \ttt{\$omega\_flags = "<expr>"}.
 
 
 
 %%%%%
 
 \section{Interface to GoSam}
 \label{sec:gosam_me}
 
 One of the supported methods for automated matrix elements from
 external providers is for the \gosam\ package. This program package
 which is a combination of \python\ scripts and \fortran\ libraries,
 allows both for tree and one-loop matrix elements (which is leading or
 next-to-leading order, depending on whether the corresponding process
 is allowed at the tree level or not). In principle, the advanced
 version of \gosam\ also allows for the evaluation of two-loop virtual
 matrix elements, however, this is currently not supported in
 \whizard. This method is invoked via the command
 \begin{code}
   $method = "gosam"
 \end{code}
 Of course, this will only work correctly of \gosam\ with all its
 subcomponents has been correctly found during configuration of
 \whizard\ and then subsequently correctly linked.
 
 In order to generate the tables for spin, flavor and color states for
 the  corresponding process, first \oMega\ is called to provide
 \fortran\ code for the interfaces to all the metadata for the
 process(es) to be evaluated. Next, the \gosam\ \python\ script is
 automatically invoked that first checks for the necessary ingredients
 to produce, compile and link the \gosam\ matrix elements. These are
 the the \ttt{Qgraf} topology generator for the diagrams, \ttt{Form} to
 perform algebra, the \ttt{Samurai}, \ttt{AVHLoop}, \ttt{QCDLoop} and
 \ttt{Ninja} libraries for Passarino-Veltman reduction, one-loop tensor
 integrals etc. As a next step, \gosam\ automatically writes and
 executes a \ttt{configure} script, and then it exchanges the Binoth
 Les Houches accord (BLHA) contract files between \whizard\ and
 itself~\cite{Binoth:2010xt,Alioli:2013nda} to check whether it
 actually generate code for the demanded process at the given
 order. Note that the contract and answer files do not have to be
 written by the user by hand, but are generated automatically within
 the program work flow initiated by the original
 \sindarin\ script. \gosam\ then generates \fortran\ code for the
 different components of the processes, compiles it and links it into a
 library, which is then automatically accessible (as an external
 process library) from inside \whizard. The phase space setup and the
 integration as well as the LO (and NLO) event generation work then in
 exactly the same way as for \oMega\ matrix elements.
 
 As an NLO calculation consists of different components for the Born,
 the real correction, the virtual correction, the subtraction part and
 possible further components depending on the details of the
 calculation, there is the possible to separately choose the matrix
 element method for those components via the keywords
 \ttt{\$loop\_me\_method}, \ttt{\$real\_tree\_me\_method},
 \ttt{\$correlation\_me\_method}  etc. These
 keywords overwrite the master switch of the \ttt{\$method} keyword.
 
 For more information on the switches and details of the functionality
 of \gosam, cf. \url{http://gosam.hepforge.org}.
 
 %%%%%
 
 \section{Interface to Openloops}
 \label{sec:openloops_me}
 
 Very similar to the case of \gosam, cf. Sec.~\ref{sec:gosam_me}, is
 the case for \openloops\ matrix elements. Also here, first \oMega\ is
 called in order to provide an interface for the spin, flavor and color
 degrees of freedom for the corresponding process. Information exchange
 between \whizard\ and \openloops\ then works in the same automatic way
 as for \gosam\ via the BLHA interface. This matrix element method is
 invoked via
 \begin{code}
   $method = "openloops"
 \end{code}
 This again is the master switch that will tell \whizard\ to use
 \openloops\ for all components, while there are special keywords to
 tailor-make the setup for the different components of an NLO
 calculation (cf. Sec.~\ref{sec:gosam_me}.
 
 The main difference between \openloops\ and \gosam\ is that for
 \openloops\ there is no process code to be generated, compiled and
 linked for a process, but a precompiled library is called and linked,
 e.g. \ttt{ppllj} for the Drell-Yan process. Of course, this library has
 to be installed on the system, but if that is not the case, the user
 can execute the \openloops\ script in the source directory of
 \openloops\ to download, compile and link the corresponding dynamic
 library. This limits (for the moment) the usage of \openloops\ to
 processes where pre-existint libraries for that specific processes
 have been generated by the \openloops\ authors. A new improved
 generator for general process libraries for \openloops\ will get rid
 of that restriction.
 
 For more information on the installation, switches and details of the
 functionality of \openloops, cf. \url{http://openloops.hepforge.org}.
 
 %%%%%
 
 \section{Interface to Recola}
 \label{sec:recola_me}
 
 The third one-loop provider (OLP) for external matrix elements that
 is supported by \whizard, is \recola. In contrast to \gosam,
 cf. Sec.~\ref{sec:gosam_me}, and \openloops,
 cf. Sec.~\ref{sec:openloops_me}, \recola\ does not use a BLHA
 interface to exchange information with \whizard, but its own
 tailor-made C interoperable library interface to communicate to the
 Monte Carlo side. \recola\ matrix elements are called for via
 \begin{code}
   $method = "recola"
 \end{code}
 \recola\ uses a highly efficient algorithm to generate process code
 for LO and NLO SM amplitudes in a fully recursive manner. At the
 moment, the setup of the interface within \whizard\ does not allow to
 invoke more than one different process in \recola: this would lead to
 a repeated initialization of the main setup of \recola\ and would
 consequently crash it. It is foreseen in the future to have a
 safeguard mechanism inside \whizard\ in order to guarantee
 initialization of \recola\ only once, but this is not yet
 implemented.
 
 Further information on the installation, details and parameters of
 \recola\ can be found at \url{http://recola.hepforge.org}.
 
 %%%%%
 
 \section{Special applications}
 \label{sec:special_me}
 
 There are also special applications with combinations of matrix
 elements from different sources for dedicated purposes like e.g. for
 the matched top--anti-top threshold in $e^+e^-$. For this special
 application which depending on the order of the matching takes only
 \oMega\ matrix elements or at NLO combines amplitudes from \oMega\ and
 \openloops, is invoked by the method:
 \begin{code}
   $method = "threshold"
 \end{code}
 
 
 \newpage
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{Implemented physics}
 \label{chap:physics}
 
 %%%%%
 
 \section{The hard interaction models}
 
 In this section, we give a brief overview over the different
 incarnations of models for the description of the realm of subatomic
 particles and their interactions inside \whizard. In
 Sec.~\ref{sec:smandfriends}, the Standard Model (SM) itself and
 straightforward extensions and modifications thereof in the gauge,
 fermionic and Higgs sector are described. Then,
 Sec.~\ref{sec:bsmmodels} gives a list and short description of all
 genuine beyond the SM models (BSM) that are currently implemented in
 \whizard\ and its matrix element generator \oMega. Additional models
 beyond that can be integrated and handled via the interfaces to
 external tools like \sarah\ and \FeynRules, or the universal model
 format \UFO, cf. Chap.~\ref{chap:extmodels}.
 
 %%%%%%%%%%%%%%%
 
 \subsection{The Standard Model and friends}
 \label{sec:smandfriends}
 
 
 %%%%
 
 \subsection{Beyond the Standard Model}
 \label{sec:bsmmodels}
 
 \begin{table}
         \begin{center}
            \begin{tabular}{|l|l|l|}
              \hline
              MODEL TYPE & with CKM matrix & trivial CKM \\
              \hline\hline
              Yukawa test model & \tt{---} & \tt{Test} \\
              \hline
              QED with $e,\mu,\tau,\gamma$ & \tt{---} &  \tt{QED} \\
              QCD with $d,u,s,c,b,t,g$ & \tt{---} &  \tt{QCD} \\
              Standard Model        & \tt{SM\_CKM} & \tt{SM} \\
              SM with anomalous gauge couplings &  \tt{SM\_ac\_CKM} &
              \tt{SM\_ac} \\
              SM with $Hgg$, $H\gamma\gamma$, $H\mu\mu$, $He^+e^-$ &
              \tt{SM\_Higgs\_CKM} & \tt{SM\_Higgs} \\
              SM with bosonic dim-6 operators &  \tt{---} &
              \tt{SM\_dim6} \\
              SM with charge 4/3 top &  \tt{---} &
              \tt{SM\_top} \\
              SM with anomalous top couplings &  \tt{---} &
              \tt{SM\_top\_anom} \\
              SM with anomalous Higgs couplings &  \tt{---} &
              \tt{SM\_rx}/\tt{NoH\_rx}/\tt{SM\_ul} \\\hline
              SM extensions for $VV$ scattering & \tt{---} &
              \tt{SSC}/\tt{AltH}/\tt{SSC\_2}/\tt{SSC\_AltT} \\\hline
              SM with $Z'$ & \tt{---} & \tt{Zprime} \\
              \hline
              Two-Higgs Doublet Model & \tt{THDM\_CKM} & \tt{THDM} \\ \hline\hline
              MSSM &   \tt{MSSM\_CKM} & \tt{MSSM} \\
              \hline
              MSSM with gravitinos &   \tt{---} & \tt{MSSM\_Grav} \\
              \hline
              NMSSM &   \tt{NMSSM\_CKM} & \tt{NMSSM} \\
              \hline
              extended SUSY models &   \tt{---} & \tt{PSSSM} \\
              \hline\hline
              Littlest Higgs &  \tt{---} & \tt{Littlest} \\
              \hline
              Littlest Higgs with ungauged $U(1)$ &  \tt{---} &
              \tt{Littlest\_Eta} \\
              \hline
              Littlest Higgs with $T$ parity &  \tt{---} &
              \tt{Littlest\_Tpar} \\
              \hline
              Simplest Little Higgs (anomaly-free) &  \tt{---} &
              \tt{Simplest} \\
              \hline
              Simplest Little Higgs (universal) &  \tt{---} &
              \tt{Simplest\_univ} \\
              \hline\hline
              SM with graviton & \tt{---} & \tt{Xdim} \\
              \hline
              UED & \tt{---} & \tt{UED} \\
              \hline
              ``SQED'' with gravitino & \tt{---} & \tt{GravTest} \\
              \hline
              Augmentable SM template & \tt{---} & \tt{Template} \\
              \hline
            \end{tabular}
          \end{center}
   \caption{\label{tab:models} List of models available in
           \whizard. There are pure test models or models implemented
           for theoretical investigations, a long list of SM variants
           as well as a large number of BSM models.}
 \end{table}
 
 \subsubsection{Strongly Interacting Models and Composite Models}
 
 Higgsless models have been studied extensively before the Higgs boson
 discovery at the LHC Run I in 2012 in order to detect possible
 loopholes in the electroweak Higgs sector discovery potential of this
 collider. The Threesite Higgsless Model is one of the simplest
 incarnations of these models, and was one of the first BSM models
 beyond SUSY and Little Higgs models that have been implemented in
 \whizard~\cite{Speckner:2010zi}. It is also called the Minimal
 Higgsless Model (MHM)~\cite{Chivukula:2006cg} is a  minimal
 deconstructed Higgsless model which contains only the first resonance
 in  the tower of Kaluza-Klein modes of a Higgsless extra-dimensional
 model. It is a non-renormalizable, effective theory whose
 gauge group is an extension of the SM with an extra $SU(2)$ gauge
 group.  The breaking of the extended electroweak gauge symmetry is
 accomplished by a set of nonlinear sigma fields which represent the
 effects of physics at a higher scale and make the theory
 nonrenormalizable. The physical vector boson spectrum contains the
 usual photon, $W^\pm$ and $Z$ bosons as well as a $W'^\pm$ and $Z'$
 boson.  Additionally, a new set of heavy fermions are introduced to
 accompany the new gauge group ``site'' which mix to form the physical
 eigenstates.  This mixing is controlled by the small mixing parameter
 $\epsilon_L$ which is adjusted to satisfy constraints from precision
 observables, such as the S parameter~\cite{Chivukula:2005xm}.
 Here, additional weak gauge boson production at the LHC was
 one of the focus of the studies with \whizard~\cite{Ohl:2008ri}.
 
 
 \subsubsection{Supersymmetric Models}
 
 \whizard/\oMega\ was the first multi-leg matrix-element/event
 generator to include the full Minimal Supersymmetric Standard Model
 (MSSM), and also the NMSSM. The SUSY implementations in \whizard\ have
 been extensively tested~\cite{Ohl:2002jp,Reuter:2009ex}, and have been
 used for many theoretical and experimental studies (some prime
 examples
 being~\cite{Kalinowski:2008fk,Robens:2008sa,Hagiwara:2005wg}.
 
 \subsubsection{Little Higgs Models}
 
 \subsubsection{Inofficial models}
 
 There have been several models that have been included within the
 \whizard/\oMega\ framework but never found their way into the official
 release series. One famous example is the non-commutative extension of
 the SM, the NCSM. There have been several studies, e.g. simulations on
 the $s$-channel production of a $Z$ boson at the photon collider
 option of the ILC~\cite{Ohl:2004tn}. Also, the production of
 electroweak gauge bosons at the LHC in the framework of the NCSM have
 been studied~\cite{Ohl:2010zf}.
 
 
 %%%%%%%%%%%%%%%
 
 \section{The SUSY Les Houches Accord (SLHA) interface}
 \label{sec:slha}
 
 
 To be filled in
 ...~\cite{Skands:2003cj,AguilarSaavedra:2005pw,Allanach:2008qq}.
 
 The neutralino sector deserves special attention. After
 diagonalization of the mass matrix expresssed in terms
 of the gaugino and higgsino eigenstates, the resulting mass
 eigenvalues may be either negative or positive. In this case, two
 procedures can be followed.  Either the masses are rendered
 positive and the associated mixing matrix gets purely imaginary
 entries or the masses are kept signed, the mixing matrix in this case
 being real.  According to the SLHA agreement, the second option is
 adopted. For a specific eigenvalue, the phase is absorbed into the
 definition of the relevant eigenvector, rendering the mass
 negative. However, \whizard\ has not yet officially tested for
 negative masses. For external SUSY models
 (cf.~Chap.~\ref{chap:extmodels}) this means, that one must be careful
 using a SLHA file with explicit factors of
 the complex unity in the mixing matrix, and on the other hand,
 real and positive masses for the neutralinos. For the hard-coded SUSY
 models, this is completely handled internally. Especially
 Ref.~\cite{Hagiwara:2005wg} discusses the details of the neutralino
 (and chargino) mixing matrix.
 
 %%%%%%%%%%%%%%%%
 
 \section{Lepton Collider Beam Spectra}
 \label{sec:beamspectra}
 
 For the simulation of lepton collider beam spectra there are two
 dedicated tools, \circeone\ and \circetwo\ that have been written as
 in principle independent tools. Both attempt to describe the
 details of electron (and positron) beams in a realistic lepton
 collider environment. Due to the quest for achieving high peak
 luminosities at $e^+e^-$ machines, the goal is to make the spatial
 extension of the beam as small as possible but keeping the area of the
 beam roughly constant. This is achieved by forcing the beams in the
 final focus into the shape of a quasi-2D bunch. Due to the high charge
 density in that bunch, the bunch electron distribution is modified by
 classical electromagnetic radiation, so called {\em beamstrahlung}.
 The two \circe\ packages are intended to perform a simulation of this
 beamstrahlung and its consequences on the electron beam spectrum as
 realistic as possible. More details about the two packages can be
 found in their stand-alone documentations. We will discuss the basic
 features of lepton-collider beam simulations in the next two sections,
 including the technicalities of passing simulations of the machine
 beam setup to \whizard. This will be followed by a section on the
 simulation of photon collider spectra, included for historical
 reasons.
 
 %%%%%
 
 \subsection{\circeone}
 
 While the bunches in a linear collider cross only once, due to their
 small size they experience a strong beam-beam effect. There is a
 code to simulate the impact of this effect on luminosity and
 background, called
 \ttt{GuineaPig++}~\cite{Schulte:1998au,Schulte:1999tx,Schulte:2007zz}.
 This takes into account the details of the accelerator, the final
 focus etc. on the structure of the beam and the main features of the
 resulting energy spectrum of the electrons and positrons. It offers
 the state-of-the-art simulation of lepton-collider beam spectra as
 close as possible to reality. However, for many high-luminosity
 simulations, event files produced with \ttt{GuineaPig++} are usually
 too small, in the sense that not enough independent events are
 available for physics simulations. Lepton collider beam spectra do
 peak at the nominal beam energy ($\sqrt{s}/2$) of the collider, and
 feature very steeply falling tails. Such steeply falling distributions
 are very poorly mapped by histogrammed distributions with fixed bin
 widths.
 
 The main working assumption to handle such spectra are being followed
 within \circeone:
 \begin{enumerate}
 \label{circe1_assumptions}
 \item The beam spectra for the two beams $P_1$ and $P_2$ factorize
   (here $x_1$ and $x_2$ are the energy fractions of the two beams,
   respectively):
   \begin{equation*}
     D_{P_1P_2} (x_1, x_2) = D_{P_1} (x_1) \cdot D_{P_2} (x_2)
   \end{equation*}
 
 \item
   The peak is described with a delta distribution, and the tail with a
   power law:
   \begin{equation*}
     D(x) = d \cdot \delta(1-x) \; + \; c \cdot x^\alpha \, (1-x)^\beta
   \end{equation*}
 \end{enumerate}
 The two powers $\alpha$ and $\beta$ are the main coefficients that can
 be tuned in order to describe the spectrum with \circeone\ as close as
 possible as the original \ttt{GuineaPig++} spectrum. More details
 about how \circeone\ works and what it does can be found in its own
 write-up in \ttt{circe1/share/doc}.
 
 \subsection{\circetwo}
 
 The two conditions listed in \ref{circe1_assumptions} are too
 restrictive and hence insufficient to describe more complicated
 lepton-collider beam spectra, as they e.g. occur in the CLIC
 drive-beam design. Here, the two beams are highly correlated and also
 a power-law description does not give good enough precision for the
 tails. To deal with these problems, \circetwo\ starts with a
 two-dimensional histogram featuring factorized, but variable bin
 widths in order to simulate the steep parts of the
 distributions. The limited statistics from too small
 \ttt{GuineaPig++} event output files leads to correlated
 fluctuations that would leave strange artifacts in the
 distributions. To abandon them, Gaussian filters are applied to smooth
 out the correlated fluctuations. Here care has to be taken when going
 from the continuum in $x$ momentum fraction space to the corresponding
 \begin{figure}
   \centering
   \includegraphics{circe2-smoothing}
   \caption{\label{fig:circe2-smoothing}
     Smoothing the bin at the $x_{e^+} = 1$ boundary with Gaussian
     filters of 3 and 10 bins width compared to no smoothing.}
 \end{figure}
 boundaries: separate smoothing procedures are being applied to the
 bins in the continuum region and those in the boundary in order to
 avoid artificial unphysical beam energy
 spreads. Fig.~\ref{fig:circe2-smoothing} shows the smoothing of the
 distribution for the bin at the $x_{e^+} = 1$ boundary. The blue dots
 show the direct \ttt{GuineaPig++} output comprising the
 fluctuations due to the low statistics. Gaussian filters with widths
 of 3 and 10 bins, respectively, have been applied (orange and green
 dots, resp.). While there is still considerable fluctuation for 3 bin
 width Gaussian filtering, the distribution is perfectly smooth for 10
 bin width. Hence, five bin widths seem a reasonable compromise for
 histograms with a total of 100 bins. Note that the bins are not
 equidistant, but shrink with a power law towards the $x_{e^-} = 1$
 boundary on the right hand side of Fig.~\ref{fig:circe2-smoothing}.
 
 \whizard\ ships (inside its subpackage \circetwo) with prepared beam
 spectra ready to be used within \circetwo\ for the ILC beam spectra
 used in the ILC
 TDR~\cite{Behnke:2013xla,Baer:2013cma,Adolphsen:2013jya,Adolphsen:2013kya,Behnke:2013lya}. These
 comprise the designed staging energies of 200 GeV, 230 GeV, 250 GeV,
 350 GeV, and 500 GeV. Note that all of these spectra up to now do not
 take polarization of the original beams on the beamstrahlung into
 account, but are polarization-averaged. For backwards compatibility,
 also the 500 GeV spectra for the TESLA
 design~\cite{AguilarSaavedra:2001rg,Richard:2001qm}, here both for
 polarized and polarization-averaged cases, are included. Correlated
 spectra for CLIC staging energies like 350 GeV, 1400 GeV and 3000 GeV
 are not yet (as of version 2.2.4) included in the \whizard\
 distribution.
 
 In the following we describe how to obtain such files with the tools
 included in \whizard (resp. \circetwo). The procedure is equivalent to
 the so-called \ttt{lumi-linker} construction used by Timothy
 Barklow (SLAC) together with the legacy version \whizard\ttt{ 1.95}.
 The workflow to produce such files is to run \ttt{GuineaPig++} with
 the following input parameters:
 \begin{Code}
   do_lumi = 7;
   num_lumi = 100000000;
   num_lumi_eg = 100000000;
   num_lumi_gg = 100000000;
 \end{Code}
 This demands from \ttt{GuineaPig++} the generation of distributions
 for the $e^-e^+$, $e^\mp \gamma$, and $\gamma\gamma$ components of the
 beamstrahlung's spectrum, respectively. These are the files
 \ttt{lumi.ee.out}, \ttt{lumi.eg.out}, \ttt{lumi.ge.out}, and
 \ttt{lumi.gg.out}, respectively. These contain pairs $(E_1, E_2)$
 of beam energies, {\em not} fractions of the original beam
 energy. Huge event numbers are out in here, as \ttt{GuineaPig++}
 will produce only a small fraction due to a very low generation
 efficiency.
 
 The next step is to transfer these output files from
 \ttt{GuineaPig++} into input files used with \circetwo. This is
 done by means of the tool \ttt{circe\_tool.opt} that is installed
 together with the \whizard\ main binary and libraries. The user should
 run this executable with the following input file:
 \begin{Code}
 { file="ilc500/ilc500.circe"                   # to be loaded by WHIZARD
   { design="ILC" roots=500 bins=100 scale=250 # E in [0,1]
     { pid/1=electron pid/2=positron pol=0     # unpolarized e-/e+
       events="ilc500/lumi.ee.out" columns=2   # <= Guinea-Pig
       lumi = 1564.763360                      # <= Guinea-Pig
       iterations = 10                         # adapting bins
       smooth = 5 [0,1) [0,1)                  # Gaussian filter 5 bins
       smooth = 5 [1] [0,1) smooth = 5 [0,1) [1] } } }
 \end{Code}
 The first line defines the output file, that later can be read in into
 the beamstrahlung's description of \whizard\ (cf. below). Then, in the
 second line the design of the collider (here: ILC for 500 GeV
 center-of-mass energy, with the number of bins) is specified. The next
 line tells the tool to take the unpolarized case, then the
 \ttt{GuineaPig++} parameters (event file and luminosity) are
 set. In the last three lines, details concerning the adaptation of the
 simulation as well as the smoothing procedure are being specified: the
 number of iterations in the adaptation procedure, and for the
 smoothing with the Gaussian filter first in the continuum and then at
 the two edges of the spectrum. For more details confer the
 documentation in the \circetwo\ subpackage.
 
 This produces the corresponding input files that can be used within
 \whizard\ to describe beamstrahlung for lepton colliders, using a
 \sindarin\ input file like:
 \begin{Code}
         beams = e1, E1 => circe2
         $circe2_file = "ilc500.circe"
         $circe2_design = "ILC"
         ?circe2_polarized = false
 \end{Code}
 
 
 %%%%%
 
 \subsection{Photon Collider Spectra}
 
 For details confer the complete write-up of the \circetwo\
 subpackage.
 
 %%%%%
 
 \section{Transverse momentum for ISR photons}
 \label{sec:isr-photon-handler}
 
 The structure functions that describe the splitting of a beam particle
 into a particle pair, of which one enters the hard interaction and the
 other one is radiated, are defined and evaluated in the strict
 collinear approximation.  In particular, this holds for the ISR
 structure function which describes the radiation of photons off a
 charged particle in the initial state.
 
 The ISR structure function that is used by \whizard\ is understood to
 be inclusive, i.e., it implicitly contains an integration over
 transverse momentum.  This approach is to be used for computing a
 total cross section via \ttt{integrate}.  In \whizard, it is possible
 to unfold this integration, as a transformation that is applied by
 \ttt{simulate} step, event by event.  The resulting modified events
 will show a proper logarithmic momentum-transfer ($Q^2$) distribution
 for the radiated photons.  The recoil is applied to the
 hard-interaction system, such that four-momentum and $\sqrt{\hat s}$
 are conserved.  The distribution is cut off by $Q_{\text{max}}^2$
 (cf. \ttt{isr\_q\_max}) for large momentum transfer, and smoothly by
 the parton mass (cf.\ \ttt{isr\_mass}) for small momentum transfer.
 
 To activate this modification, set
 \begin{Code}
   ?isr_handler = true
   $isr_handler_mode = "recoil"
 \end{Code}
 before, or as an option to, the \ttt{simulate} command.
 
 Limitations: the current implementation of the $p_T$ modification
 works only for the symmetric double-ISR case, i.e., both beams have to
 be charged particles with identical mass (e.g., $e^+e^-$).  The mode
 \ttt{recoil} generates exactly one photon per beam, i.e., it modifies
 the momentum of the single collinear photon that the ISR structure
 function implementation produces, for each beam.  (It is foreseen that
 further modes or options will allow to generate multiple photons.
 Alternatively, the \pythia\ shower can be used to simulate multiple
 photons radiated from the initial state.)
 
 %%%%%
 
 \section{Transverse momentum for the EPA approximation}
 \label{sec:epa-beam-handler}
 
 For the equivalent-photon approximation (EPA), which is also defined
 in the collinear limit, recoil momentum can be inserted into generated
 events in an entirely analogous way.  The appropriate settings are
 \begin{Code}
   ?epa_handler = true
   $epa_handler_mode = "recoil"
 \end{Code}
 
 Limitations: as for ISR, the current implementation of the $p_T$
 modification works only for the symmetric double-EPA case.  Both
 incoming particles of the hard process must be photons, while both
 beams must be charged particles with identical mass (e.g., $e^+e^-$).
 Furthermore, the current implementation does not respect the
 kinematical limit parameter \verb|epa_q_min|, it has to be set to
 zero. In effect, the lower $Q^2$ cutoff is determined by the
 beam-particle mass \verb|epa_mass|, and the upper cutoff is either
 given by $Q_{\text{max}}$ (the parameter
 \verb|epa_q_max|), or by the limit $\sqrt{s}$ if this is not set.
 
 It is possible to combine the ISR and EPA handlers, for processes
 where ISR is active for one of the beams, EPA for the other beam.  For
 this scenario to work, both handler switches must be on, and both mode
 strings must coincide.  The parameters are set separately for ISR and
 EPA, as described above.
 
 %%%%%
 
 \section{Resonances and continuum}
 
 \subsection{Complete matrix elements}
 
 Many elementary physical processes are composed of contributions that can be
 qualified as (multiply) \emph{resonant} or \emph{continuum}.  For instance,
 the amplitude for the process $e^+e^-\to q\bar q q\bar q$, evaluated at tree
 level in perturbation theory, contains Feynman diagrams with zero, one, or two
 $W$ and $Z$ bosons as virtual lines.  If the kinematical constraints allow
 this, two vector bosons can become simultaneously on-shell in part of phase
 space.  To a first approximation, this situation is understood as $W^+W^-$ or
 $ZZ$ production with subsequent decay.  The kinematical distributions show
 distinct resonances in the quark-pair spectra.  Other graphs contain only one
 s-channel $W/Z$ boson, or none at all, such as graphs with $q\bar q$
 production and subsequent gluon radiation, splitting into another $q\bar q$
 pair.
 
 A \whizard\ declaration of the form
 \begin{Code}
         process q4 = e1, E1 => u, U, d, D
 \end{Code}
 produces the full set of graphs for the selected final state, which after
 squaring and integrating yields the exact tree-level result for the process.
 The result contains all doubly and singly resonant parts, with correct
 resonance shapes, as well as the continuum contribution and all interference.
 This is, to given order in perturbation theory, the best possible
 approximation to the true result.
 
 \subsection{Processes restricted to resonances}
 
 For an intuitive separation of a two-boson ``signal'' contribution, it is
 possible to restrict the set of graphs to a certain intermediate state.  For
 instance, the declaration
 \begin{Code}
   process q4_zz = e1, E1 => u, U, d, D { $restrictions = "3+4~Z && 5+6~Z" }
 \end{Code}
 generates an amplitude that contains only those Feynman graphs where the
 specified quarks are connected to a $Z$ virtual line.  The result may be
 understood as $ZZ$ production with subsequent decay, where the $Z$ resonances
 exhibit a Breit-Wigner shape.  Combining this with the
 analogous $W^+W^-$ restricted process, the user can generate ``signal''
 processes.
 
 Adding both ``signal'' cross sections $WW$ and $ZZ$ will result in a
 reasonable approximation to the exact tree-level cross section.  The amplitude
 misses the single-resonant and continuum contributions, and the squared
 amplitude misses the interference terms, however.  More importantly, the
 restricted processes as such are not gauge-invariant (with respect to the
 electroweak gauge group), and they are no longer dominant away from resonant
 kinematics.  We therefore strongly recommend that such restricted processes
 are always accompanied by a cut setup that restricts the kinematics to an
 approximately on-shell pattern for both resonances.  For instance:
 \begin{Code}
   cuts = all 85 GeV < M < 95 GeV [u:U]
      and all 85 GeV < M < 95 GeV [d:D]
 \end{Code}
 In this region, the gauge-dependent and continuum contributions are strictly
 subdominant.  Away from the resonance(s), the results for a restricted process
 are meaningless, and the full process has to be computed instead.
 
 \subsection{Factorized processes}
 
 Another method for obtaining the signal contribution is a proper factorization
 into resonance production and decay.  We would have to generate a production
 process and two decay processes:
 \begin{Code}
         process z_uu = Z => u, U
         process z_dd = Z => d, D
         process zz = e1, E1 => Z, Z
 \end{Code}
 All three processes must be integrated.  The integration results are partial
 decay widths and the $ZZ$ production cross section, respectively.  (Note that
 cut expressions in \sindarin\ apply to all integrations, so make sure that
 no production-process cuts are active when integrating the decay
 processes.)
 
 During a later event-generation step, the $Z$ decays can then be activated by declaring the $Z$ as
 unstable,
 \begin{Code}
         unstable Z (z_uu, z_dd)
 \end{Code}
 and then simulating the production process
 \begin{Code}
         simulate (zz)
 \end{Code}
 The generated events will consist of four-fermion final states, including all
 combinations of both decay modes.  It is important to note that in this setup,
 the invariant $u\bar u$ and $d\bar d$ masses will be always \emph{exactly}
 equal to the $Z$ mass.  There is no Breit-Wigner shape involved.  However, in
 this approximation the results are gauge-invariant, as there is no off-shell
 contribution involved.
 
 For further details on factorized processes and spin correlations,
 cf.\ Sec.~\ref{sec:spin-correlations}.
 
 
 \subsection{Resonance insertion in the event record}
 
 From the above discussion, we may conclude that it is always preferable to
 compute the complete process for a given final state, as long as this is
 computationally feasible.  However, in the simulation step this approach also
 has a drawback.  Namely, if a parton-shower module (see below) is switched on,
 the parton-shower algorithm relies on event details in order to determine the
 radiation pattern of gluons and further splitting.  In the generated event
 records, the full-process events carry the signature of non-resonant continuum
 production with no intermediate resonances.  The parton shower will thus start
 the evolution at the process energy scale, the total available energy.  By
 contrast, for an electroweak production and decay process, the evolution
 should start only at the vector boson mass, $m_Z$.  In effect, even though the
 resonant contribution of $WW$ and $ZZ$ constitutes the bulk of the cross
 section, the radiation pattern follows the dynamics of four-quark continuum
 production.  In general, the number of radiated hadrons will be too high.
 
 
 \begin{figure}
   \begin{center}
     \includegraphics[width=.41\textwidth]{resonance_e_gam}
     \includegraphics[width=.41\textwidth]{resonance_n_charged} \\
     \includegraphics[width=.41\textwidth]{resonance_n_hadron}
     \includegraphics[width=.41\textwidth]{resonance_n_particles} \\
     \includegraphics[width=.41\textwidth]{resonance_n_photons}
     \includegraphics[width=.41\textwidth]{resonance_n_visible}
   \end{center}
   \caption{The process $e^+e^- \to jjjj$ at 250 GeV center-of-mass
     energy is compared transferring the partonic events naively to the
     parton shower, i.e. without respecting any intermediate resonances
     (red lines). The blue lines show the process factorized into $WW$
     production and decay, where the shower knows the origin of the two
     jet pairs. The orange and dark green lines show the resonance
     treatment as mentioned in the text, with
     \ttt{resonance\_on\_shell\_limit = 1} and \ttt{= 4},
     respectively. \pythiasix\ parton shower and hadronization with the
     OPAL tune have been used. The observables are: photon energy
     distribution and number of charged tracks (upper line left/right,
     number of hadrons and total number of particles (middle
     left/right), and number of photons and neutral particles (lower
     line left/right).}
 \end{figure}
 
 To overcome this problem, there is a refinement of the process description
 available in \whizard.  By modifying the process declaration to
 \begin{Code}
   ?resonance_history = true
   resonance_on_shell_limit = 4
   process q4 = e1, E1 => u, U, d, D
 \end{Code}
 we advise the program to produce not just the complete matrix element, but
 also all possible restricted matrix elements containing resonant intermediate
 states.  This has no effect at all on the integration step, and thus on the
 total cross section.
 
 However, when subsequently events are generated with this setting, the program
 checks, for each event, the kinematics and determines the set of potentially
 resonant contributions.  The criterion is whether the off-shellness of a
 particular would-be resonance is less than the resonance width multiplied by
 the value of \verb|resonance_on_shell_limit| (default value $=4$).  For the
 set of resonance histories which pass this criterion (which can be empty),
 their respective squared matrix element is related to the full-process matrix
 element.  The ratio is interpreted as a probability.  The random-number
 generator then selects one or none of the resonance histories, and modifies
 the event record accordingly.  In effect, for an appropriate fraction of the
 events, depending on the kinematics, the parton-shower module is provided with
 resonance information, so it can adjust the radiation pattern accordingly.
 
 It has to be mentioned that generating the matrix-element code for all
 possible resonance histories takes additional computing resources.  In the
 current default setup, this feature is switched off.  It has to be explicitly
 activated via the \verb|?resonance_history| flag.
 
 Also, the feature can be activated or deactivated individually for
 each process, such as in
 \begin{Code}
   ?resonance_history = true
   process q4_with_res = e1, E1 => u, U, d, D  { ?resonance_history = true }
   process q4_wo_res   = e1, E1 => u, U, d, D  { ?resonance_history = false }
 \end{Code}
 If the flag is \verb|false| for a process, no resonance code will be
 generated.  Similarly, the flag has to be globally or locally active
 when \verb|simulate| is called, such that the feature takes effect for
 event generation.
 
 There are two additional parameters that can fine-tune the conditions for
 resonance insertion in the event record.  Firstly, the parameter
 \verb|resonance_on_shell_turnoff|, if nonzero, enables a Gaussian suppression
 of the probability for resonance insertion.  For instance, setting
 \begin{Code}
   ?resonance_history = true
   resonance_on_shell_turnoff = 4
   resonance_on_shell_limit = 8
 \end{Code}
 will reduce the probability for the event to be qualified as resonant by
 $e^{-1}= 37\,\%$ if the kinematics is off-shell by four units of the width,
 and by $e^{-4}=2\,\%$ at eight units of the width.  Beyond this point, the
 setting of the \verb|resonance_on_shell_limit| parameter eliminates resonance
 insertion altogether.  In effect, the resonance-background transition is
 realized in a smooth way.  Secondly, within the resonant-kinematics range the
 probability for qualifying the event as background can be reduced by the
 parameter \verb|resonance_background_factor| (default value $=1$) to a number
 between zero and one.  Setting this to zero means that the event will be
 necessarily qualified as resonant, if it falls within the resonant-kinematics
 range.
 
 Note that if an event, by the above mechanism, is identified as following a
 certain resonance history, the assigned color flow will be chosen to match the
 resonance history, not the complete matrix element.  This may result in a
 reassignment of color flow with respect to the original partonic event.
 
 Finally, we mention the order of execution: any additional
 matrix element code is compiled and linked when \verb|compile| is
 executed for the processes in question.  If this command is omitted,
 the \verb|simulate| command will trigger compilation.
 
 
 \section{Parton showers and Hadronization}
 
 In order to produce sensible events, final state QCD (and also QED)
 radiation has to be considered as well as the binding of strongly
 interacting partons into mesons and baryons. Furthermore, final state
 hadronic resonances undergo subsequent decays into those particles
 showing up in (or traversing) the detector. The latter are mostly
 pions, kaons, photons, electrons and muons.
 
 The physics associated with these topics can be divided into the
 perturbative part which is the regime of the parton shower, and the
 non-perturbative part which is the regime for the
 hadronization. \whizard\ comes with its own two different parton
 shower implementations, an analytic and a so-called $k_T$-ordered
 parton shower that will be detailed in the next section.
 
 Note that in general it is not advisable to use different shower and
 hadronization methods, or in other words, when using shower and
 hadronization methods from different programs these would have to be
 tuned together again with the corresponding data.
 
 Parton showers are approximations to full matrix elements taking only
 the leading color flow into account, and neglecting all interferences
 between different amplitudes leading to the same exclusive final
 state. They rely on the QCD (and QED) splitting functions to describe
 the emissions of partons off other partons. This is encoded in the
 so-called Sudakov form factor~\cite{Sudakov:1954sw}:
 \begin{equation*}
   \Delta( t_1, t_2) = \exp \left[ \int\limits_{t_1}^{t_2} \mbox{d} t
     \int\limits_{z_-}^{z_+} \mbox{d} z \frac{\alpha_s}{2 \pi t} P(z)
     \right]
 \end{equation*}
 This gives the probability for a parton to evolve from scale $t_2$ to
 $t_1$ without any further emissions of partons. $t$ is the evolution
 parameter of the shower, which can be a parton energy, an emission
 angle, a virtuality, a transverse momentum etc. The variable $z$
 relates the two partons after the branching, with the most common
 choice being the ratio of energies of the parton after and before the
 branching. For final-state radiation brachings occur after the hard
 interaction, the evolution of the shower starts at the scale of the
 hard interaction, $t \sim \hat{s}$, down to a cut-off scale $t =
 t_{\text{cut}}$ that marks the transition to the non-perturbative
 regime of hadronization. In the space-like evolution for the
 initial-state shower, the evolution is from a cut-off representing the
 factorization scale for the parton distribution functions (PDFs) to the
 inverse of the hard process scale, $-\hat{s}$. Technically, this
 evolution is then backwards in (shower) time~\cite{Sjostrand:1985xi},
 leading to the necessity to include the PDFs in the Sudakov factors.
 
 The main switches for the shower and hadronization which are realized
 as transformations on the partonic events within \whizard\ are
 \ttt{?allow\_shower} and \ttt{?allow\_hadronization}, which are
 true by default and only there for technical reasons. Next, different
 shower and hadronization methods can be chosen within \whizard:
 \begin{code}
   $shower_method = "WHIZARD"
   $hadronization_method = "PYTHIA6"
 \end{code}
 The snippet above shows the default choices in \whizard\, namely
 \whizard's intrinsic parton shower, but \pythiasix\ as hadronization
 tool. (Note that \whizard\ does not have its own hadronization module
 yet.)  The usage of \pythiasix\ for showering and hadronization will
 be explained in Sec.~\ref{sec:pythia6}, while the two different
 implementations of the \whizard\ homebrew parton showers are discussed
 in Sec.~\ref{sec:ktordered} and~\ref{sec:analytic}, respectively.
 
 %%%%%
 
 \subsection{The $k_T$-ordered parton shower}
 \label{sec:ktordered}
 
 %%%%%
 
 \subsection{The analytic parton shower}
 \label{sec:analytic}
 
 %%%%%
 
 \subsection{Parton shower and hadronization from \pythiasix}
 \label{sec:pythia6}
 
 Development of the \pythiasix\ generator for parton shower and
 hadronization (the \fortran\ version) has been discontinued by the
 authors several years ago. Hence, the final release of that program is
 frozen. This allowed to ship this final version, v6.427, with the
 \whizard\ distribution without the need of updating it all the
 time. One of the main reasons for that inclusion -- besides having the
 standard tool for showering and hadronization for decays at hand -- is
 to allow for backwards validation within \whizard\ particularly for
 the event samples generated for the development of linear collider
 physics: first for TESLA, JLC and NLC, and later on for the Conceptual
 and Technical Design Report for ILC, for the Conceptual Design Report
 for CLIC as well as for the Letters of Intent for the LC detectors,
 ILD and SiD.
 
 Usually, an external parton shower and hadronization program (PS) is
 steered via the transfer of event files that are given to the PS via
 LHE events, while the PS program then produces hadron level events,
 usually in HepMC format. These can then be directed towards a full or
 fast detector simulation program. As \pythiasix\ has been completely
 integrated inside the \whizard\ framework, the showered or more
 general hadron level events can be returned to and kept inside
 \whizard's internal event record, and hence be used in \whizard's
 internal event analysis. In that way, the events can be also written
 out in event formats that are not supported by \pythiasix,
 e.g. \ttt{LCIO} via the output capabilities of \whizard.
 
 There are several switches to directly steer \pythiasix\ (the values
 in brackets correspond to the \pythiasix\ variables):
 \begin{code}
   ps_mass_cutoff = 1 GeV                  [PARJ(82)]
   ps_fsr_lambda = 0.29 GeV                [PARP(72)]
   ps_isr_lambda = 0.29 GeV                [PARP(61)]
   ps_max_n_flavors = 5                    [MSTJ(45)]
   ?ps_isr_alphas_running = true           [MSTP(64)]
   ?ps_fsr_alphas_running = true           [MSTJ(44)]
   ps_fixed_alphas = 0.2                   [PARU(111)]
   ?ps_isr_angular_ordered = true          [MSTP(62)]
   ps_isr_primordial_kt_width = 1.5 GeV    [PARP(91)]
   ps_isr_primordial_kt_cutoff = 5.0 GeV   [PARP(93)]
   ps_isr_z_cutoff = 0.999                 [1-PARP(66)]
   ps_isr_minenergy = 2 GeV                [PARP(65)]
   ?ps_isr_only_onshell_emitted_partons =
         true                              [MSTP(63)]
 \end{code}
 The values given above are the default values. The first value
 corresponds to the \pythiasix\ parameter \ttt{PARJ(82)}, its
 squared being the minimal virtuality that is allowed for the parton
 shower, i.e. the cross-over to the hadronization. The same parameter
 is used also for the \whizard\ showers. \ttt{ps\_fsr\_lambda} is
 the equivalent of \ttt{PARP(72)} and is the $\Lambda_{\text{QCD}}$
 for the final state shower. The corresponding variable for the initial
 state shower is called \ttt{PARP(61)} in \pythiasix. By the next
 variable (\ttt{MSTJ(45)}), the maximal number of flavors produced
 in splittings in the shower is given, together with the number of
 active flavors in the running of
 $\alpha_s$. \ttt{?ps\_isr\_alphas\_running} which corresponds to
 \ttt{MSTP(64)} in \pythiasix\ determines whether or net a running
 $\alpha_s$ is taken in the space-like initial state showers. The same
 variable for the final state shower is \ttt{MSTJ(44)}. For fixed
 $\alpha_s$, the default value is given by \ttt{ps\_fixed\_alpha},
 corresponding to \ttt{PARU(111)}. \ttt{MSTP(62)} determines
 whether the ISR shower is angular order, i.e. whether angles are
 increasing towards the hard interaction. This is per default true, and
 set in the variable \ttt{?ps\_isr\_angular\_ordered}. The width of
 the distribution for the primordial (intrinsic) $k_T$ distribution
 (which is a non-perturbative quantity) is the \pythiasix\ variable
 \ttt{PARP(91)}, while in \whizard\ it is given by
 \ttt{pythia\_isr\_primordial\_kt\_width}. The next variable
 (\ttt{PARP(93}) gives the upper cutoff for that distribution, which
 is 5 GeV per default. For splitting in space-like showers, there is a
 cutoff on the $z$ variable named \ttt{ps\_isr\_z\_cutoff} in
 \whizard. This corresponds to one minus the value of the
 \pythiasix\ parameter \ttt{PARP(66)}. \ttt{PARP(65)}, on the
 other hand, gives the minimal (effective) energy for a time-like or
 on-shell emitted parton on a space-like QCD shower, given by the
 \sindarin\ parameter \ttt{ps\_isr\_minenergy}. Whether or not
 partons emitted from space-like showers are allowed to be only
 on-shell is given by
 \ttt{?ps\_isr\_only\_onshell\_emitted\_partons}, \ttt{MSTP(63)}
 in \pythiasix\ language.
 For more details confer the
 \pythiasix\ manual~\cite{Sjostrand:2006za}.
 
 Any other non-standard \pythiasix\ parameter can be fed into the
 parton shower via the string variable
 \begin{code}
   $ps_PYTHIA_PYGIVE = "...."
 \end{code}
 Variables set here get preference over the ones set explicitly by
 dedicated \sindarin\ commands. For example, the OPAL tune for hadronic
 final states can be set via:
 \begin{code}
   $ps_PYTHIA_PYGIVE = "MSTJ(28)=0; PMAS(25,1)=120.; PMAS(25,2)=0.3605E-02; MSTJ(41)=2;
    MSTU(22)=2000; PARJ(21)=0.40000; PARJ(41)=0.11000; PARJ(42)=0.52000; PARJ(81)=0.25000;
    PARJ(82)=1.90000; MSTJ(11)=3; PARJ(54)=-0.03100; PARJ(55)=-0.00200; PARJ(1)=0.08500;
    PARJ(3)=0.45000; PARJ(4)=0.02500; PARJ(2)=0.31000; PARJ(11)=0.60000; PARJ(12)=0.40000;
    PARJ(13)=0.72000; PARJ(14)=0.43000; PARJ(15)=0.08000; PARJ(16)=0.08000;
    PARJ(17)=0.17000; MSTP(3)=1;MSTP(71)=1"
 \end{code}
 
 \vspace{0.5cm}
 
 A very common error that appears quite often when using
 \pythiasix\ for SUSY or any other model having a stable particle that
 serves as a possible Dark Matter candidate, is the following
 warning/error message:
 \begin{Code}
      Advisory warning type 3 given after        0 PYEXEC calls:
      (PYRESD:) Failed to decay particle  1000022 with mass   15.000
 ******************************************************************************
 ******************************************************************************
 *** FATAL ERROR: Simulation: failed to generate valid event after 10000 tries
 ******************************************************************************
 ******************************************************************************
 \end{Code}
 In that case, \pythiasix\ gets a stable particle (here the lightest
 neutralino with the PDG code 1000022) handed over and does not know
 what to do with it. Particularly, it wants to treat it as a heavy
 resonance which should be decayed, but does not know how do
 that. After a certain number of tries (in the example abobe 10k),
 \whizard\ ends with a fatal error telling the user that the event
 transformation for the parton shower in the simulation has failed
 without producing a valid event. The solution to work around that
 problem is to let \pythiasix\ know that the neutralino (or any other
 DM candidate) is stable by means of
 \begin{code}
   $ps_PYTHIA_PYGIVE = "MDCY(C1000022,1)=0"
 \end{code}
 Here, 1000022 has to be replaced by the stable dark matter candidate
 or long-lived particle in the user's favorite model. Also note that
 with other options being passed to \pythiasix\, the \ttt{MDCY}
 option above has to be added to an existing
 \ttt{\$ps\_PYTHIA\_PYGIVE} command separated by a semicolon.
 
 %%%%%
 
 \subsection{Parton shower and hadronization from \pythiaeight}
 
 \subsection{Other tools for parton shower and hadronization}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{More on Event Generation}
 \label{chap:events}
 
 In order to perform a physics analysis with \whizard\ one has to
 generate events. This seems to be a trivial statement, but as there
 have been any questions like "My \whizard\ does not produce plots --
 what has gone wrong?" we believe that repeating that rule is
 worthwile. Of course, it is not mandatory to use \whizard's own analysis
 set-up, the user can always choose to just generate events and use
 his/her own analysis package like \ttt{ROOT}, or \ttt{TopDrawer}, or
 you name it for the analysis.
 
 Accordingly, we first start to describe how to generate events and
 what options there are -- different event formats, renaming output
 files, using weighted or unweighted events with different
 normalizations. How to re-use and manipulate already generated event
 samples, how to limit the number of events per file, etc. etc.
 
 \section{Event generation}
 
 To explain how event generation works, we again take our favourite
 example, $e^+e^- \to \mu^+ \mu^-$,
 \begin{verbatim}
   process eemm = e1, E1 => e2, E2
 \end{verbatim}
 The command to trigger generation of events is \ttt{simulate
   (<proc\_name>) \{ <options> \}}, so in our case -- neglecting any
 options for now -- simply:
 \begin{verbatim}
   simulate (eemm)
 \end{verbatim}
 When you run this \sindarin\ file you will experience a fatal error:
 \ttt{FATAL ERROR: Colliding beams: sqrts is zero (please set
 sqrts)}. This is because \whizard\ needs to compile and integrate the
 process \ttt{eemm} first before event simulation, because it needs the
 information of the corresponding cross section, phase space
 parameterization and grids. It does both automatically, but you have
 to provide \whizard\ with the beam setup, or at least with the
 center-of-momentum energy.  A corresponding \ttt{integrate} command
 like
 \begin{verbatim}
   sqrts = 500 GeV
   integrate (eemm) { iterations = 3:10000 }
 \end{verbatim}
 obviously has to appear {\em before} the corresponding \ttt{simulate}
 command (otherwise you would be punished by the same error message as
 before). Putting things in the correct order results in an output
 like:
 \begin{footnotesize}
 \begin{verbatim}
 | Reading model file '/usr/local/share/whizard/models/SM.mdl'
 | Preloaded model: SM
 | Process library 'default_lib': initialized
 | Preloaded library: default_lib
 | Reading commands from file 'bla.sin'
 | Process library 'default_lib': recorded process 'eemm'
 sqrts =  5.000000000000E+02
 | Integrate: current process library needs compilation
 | Process library 'default_lib': compiling ...
 | Process library 'default_lib': keeping makefile
 | Process library 'default_lib': keeping driver
 | Process library 'default_lib': active
 | Process library 'default_lib': ... success.
 | Integrate: compilation done
 | RNG: Initializing TAO random-number generator
 | RNG: Setting seed for random-number generator to 29912
 | Initializing integration for process eemm:
 | ------------------------------------------------------------------------
 | Process [scattering]: 'eemm'
 |   Library name  = 'default_lib'
 |   Process index = 1
 |   Process components:
 |     1: 'eemm_i1':   e-, e+ => mu-, mu+ [omega]
 | ------------------------------------------------------------------------
 | Beam structure: [any particles]
 | Beam data (collision):
 |   e-  (mass = 5.1099700E-04 GeV)
 |   e+  (mass = 5.1099700E-04 GeV)
 |   sqrts = 5.000000000000E+02 GeV
 | Phase space: generating configuration ...
 | Phase space: ... success.
 | Phase space: writing configuration file 'eemm_i1.phs'
 | Phase space: 2 channels, 2 dimensions
 | Phase space: found 2 channels, collected in 2 groves.
 | Phase space: Using 2 equivalences between channels.
 | Phase space: wood
 Warning: No cuts have been defined.
 | OpenMP: Using 8 threads
 | Starting integration for process 'eemm'
 | Integrate: iterations = 3:10000
 | Integrator: 2 chains, 2 channels, 2 dimensions
 | Integrator: Using VAMP channel equivalences
 | Integrator: 10000 initial calls, 20 bins, stratified = T
 | Integrator: VAMP
 |=============================================================================|
 | It      Calls  Integral[fb]  Error[fb]   Err[%]    Acc  Eff[%]   Chi2 N[It] |
 |=============================================================================|
    1       9216  4.2833237E+02  7.14E-02    0.02    0.02*  40.29
    2       9216  4.2829071E+02  7.08E-02    0.02    0.02*  40.29
    3       9216  4.2838304E+02  7.04E-02    0.02    0.02*  40.29
 |-----------------------------------------------------------------------------|
    3      27648  4.2833558E+02  4.09E-02    0.01    0.02   40.29    0.43   3
 |=============================================================================|
 | Time estimate for generating 10000 events: 0d:00h:00m:04s
 | Creating integration history display eemm-history.ps and eemm-history.pdf
 | Starting simulation for process 'eemm'
 | Simulate: using integration grids from file 'eemm_m1.vg'
 | RNG: Initializing TAO random-number generator
 | RNG: Setting seed for random-number generator to 29913
 | OpenMP: Using 8 threads
 | Simulation: requested number of events = 0
 |             corr. to luminosity [fb-1] =   0.0000E+00
 | Events: writing to raw file 'eemm.evx'
 | Events: generating 0 unweighted, unpolarized events ...
 | Events: event normalization mode '1'
 |         ... event sample complete.
 | Events: closing raw file 'eemm.evx'
 | There were no errors and    1 warning(s).
 | WHIZARD run finished.
 |=============================================================================|
 \end{verbatim}
 \end{footnotesize}
 
 So, \whizard\ tells you that it has entered simulation mode, but besides
 this, it has not done anything. The next step is that you have to
 demand event generation -- there are two ways to do this: you could
 either specify a certain number, say 42, of events you want to have
 generated by \whizard, or you could provide a number for an integrated
 luminosity of some experiment. (Note, that if you choose to take both
 options, \whizard\ will take the one which gives the larger event
 sample. This, of course, depends on the given process(es) -- as well
 as cuts -- and its corresponding cross section(s).) The first of these
 options is set with the command: \ttt{n\_events = <number>}, the
 second with \ttt{luminosity = <number> <opt. unit>}.
 
 Another important point already stated several times in the manual is
 that \whizard\ follows the commands in the steering \sindarin\ file in a
 chronological order. Hence, a given number of events or luminosity
 {\em after} a \ttt{simulate} command will be ignored -- or are
 relevant only for any \ttt{simulate} command potentially following
 further down in the \sindarin\ file. So, in our case, try:
 \begin{verbatim}
  n_events = 500
  luminosity = 10
  simulate (eemm)
 \end{verbatim}
 Per default, numbers for integrated luminosity are understood as
 inverse femtobarn. So, for the cross section above this would
 correspond to 4283 events, clearly superseding the demand for 500
 events. After reducing the luminosity number from ten to one inverse
 femtobarn, 500 is the larger number of events taken by \whizard\ for
 event generation. Now \whizard\ tells you:
 \begin{verbatim}
 | Simulation: requested number of events = 500
 |             corr. to luminosity [fb-1] =   1.1673E+00
 | Events: reading from raw file 'eemm.evx'
 | Events: reading 500 unweighted, unpolarized events ...
 | Events: event normalization mode '1'
 | ... event file terminates after 0 events.
 | Events: appending to raw file 'eemm.evx'
 | Generating remaining  500 events ...
 |         ... event sample complete.
 | Events: closing raw file 'eemm.evx'
 \end{verbatim}
 I.e., it evaluates the luminosity to which the sample of 500 events
 would correspond to, which is now, of course, bigger than the $1
 \fb^{-1}$ explicitly given for the luminosity. Furthermore, you can
 read off that a file \ttt{whizard.evx} has been generated, containing
 the demanded 500 events. (It was there before containing zero events,
 because to \ttt{n\_events} or \ttt{luminosity} value had been
 set. \whizard\ then tried to get the events first from file before
 generating new ones). Files with the suffix \ttt{.evx} are binary
 format event files, using a machine-dependent \whizard-specific
 event file format. Before we list the event formats supported by
 \whizard, the next two sections will tell you more about unweighted and
 weighted events as well as different possibilities to normalize events
 in \whizard.
 
 As already explained for the libraries, as well as the phase space and
 grid files in Chap.~\ref{chap:sindarin}, \whizard\ is trying to re-use
 as much information as possible. This is of course also true for the
 event files. There are special MD5 check sums testing the integrity
 and compatibility of the event files. If you demand for a process for
 which an event file already exists (as in the example above, though it
 was empty) equally many or less events than generated before,
 \whizard\ will not generate again but re-use the existing events (as
 already explained, the events are stored in a \whizard-own
 binary event format, i.e. in a so-called \ttt{.evx} file. If you
 suppress generation of that file, as will be described in subsection
 \ref{sec:eventformats} then \whizard\ has to generate events all the
 time). From version v2.2.0 of \whizard\ on, the program is also able
 to read in event from different event formats. However, most event
 formats do not contain as many information as \whizard's internal
 format, and a complete reconstruction of the events might not be
 possible. Re-using event files is very practical for doing several
 different analyses with the same data, especially if there are many
 and big data samples. Consider
 the case, there is an event file with 200 events, and you now ask
 \whizard\ to generate 300 events, then it will re-use the 200 events
 (if MD5 check sums are OK!), generate the remaining 100 events and
 append them to the existing file. If the user for some reason,
 however, wants to regenerate events (i.e. ignoring possibly existing
 events), there is the command option \ttt{whizard --rebuild-events}.
 
 %%%%%%%%%
 
 \section{Unweighted and weighted events}
 
 \whizard\ is able to generate unweighted events, i.e. events that are
 distributed uniformly and each contribute with the same event weight
 to the whole sample. This is done by mapping out the phase space of
 the process under consideration according to its different phase space
 channels (which each get their own weights), and then unweighting the
 sample of weighted events. Only a sample of unweighted events could in
 principle be compared to a real data sample from some experiment. The
 seventh column in the \whizard\ iteration/adaptation procedure tells you
 about the efficiency of the grids, i.e. how well the phase space is
 mapped to a flat function. The better this is achieved, the higher the
 efficiency becomes, and the closer the weights of the different phase
 space channels are to uniformity. This means, for higher efficiency
 less weighted events ("calls") are needed to generate a single
 unweighted event. An efficiency of 10 \% means that ten weighted
 events are needed to generate one single unweighted event. After the
 integration is done, \whizard\ uses the duration of calls during the
 adaptation to estimate a time interval needed to generate 10,000
 unweighted events. The ability of the adaptive multi-channel Monte
 Carlo decreases with the number of integrations, i.e. with the number
 of final state particles. Adding more and more final state particles
 in general also increases the complexity of phase space, especially
 its singularity structure. For a $2 \to 2$ process the efficiency is
 roughly of the order of several tens of per cent. As a rule of thumb,
 one can say that with every additional pair of final state particle
 the average efficiency one can achieve decreases by a factor of five
 to ten.
 
 The default of \whizard\ is to generate {\em unweighted} events. One can
 use the logical variable \ttt{?unweighted = false} to disable
 unweighting and generate weighted events. (The command
 \ttt{?unweighted = true} is a tautology, because \ttt{true} is the
 default for this variable.) Note that again this command has to appear
 {\em before} the corresponding \ttt{simulate} command, otherwise it will
 be ignored or effective only for any \ttt{simulate} command appearing
 later in the \sindarin\ file.
 
 In the unweighted procedure, \whizard\ is keeping track of the highest
 weight that has been appeared during the adaptation, and the
 efficiency for the unweighting has been estimated from the average
 value of the sampling function compared to the maximum value. In
 principle, during event generation no events should be generated whose
 sampling function value exceeds the maximum function value encountered
 during the grid adaptation. Sometimes, however, there are numerical
 fluctuations and such events are happening. They are called {\em
 excess events}. \whizard\ does keep track of these excess events
 during event generation and will report about them, e.g.:
 \begin{code}
 Warning: Encountered events with excess weight: 9 events (  0.090 %)
 | Maximum excess weight = 6.083E-01
 | Average excess weight = 2.112E-04
 \end{code}
 Whenever in an event generation excess events appear, this shows that
 the adaptation of the sampling function has not been perfect. When the
 number of excess weights is a finite number of percent, you should
 inspect the phase-space setup and try to improve its settings to get a
 better adaptation.
 
 Generating \emph{weighted} events is, of course, much faster if the
 same number of events is requested.  Each event carries a weight
 factor which is taken into account for any internal analysis
 (histograms), and written to file if an external file format has been
 selected.  The file format must support event weights.
 
 In a weighted event sample, there is typically a fraction of events
 which effectively have weight zero, namely those that have been
 created by the phase-space sampler but do not pass the requested
 cuts.  In the default setup, those events are silently dropped, such
 that the events written to file or available for analysis all have
 nonzero weight.  However, dropping such events affects the overall
 normalization.  If this has happened, the program will issue a warning
 of the form
 \begin{code}
 | Dropped events (weight zero) = 1142 (total 2142)
 Warning: All event weights must be rescaled by f = 4.66853408E-01
 \end{code}
 This factor has to be applied by hand to any external event files (and
 to internally generated histograms).  The program cannot include the
 factor in the event records, because it is known only after all events
 have been generated.  To avoid this problem, there is the logical flag
 \ttt{?keep\_failed\_events} which tells \whizard\ not to drop events with
 weight zero.  The normalization will be correct, but the event sample
 will include invalid events which have to be vetoed by their zero
 weight, before any operations on the event record are performed.
 
 
 %%%%%%%%%
 
 \section{Choice on event normalizations}
 
 There are basically four different choices to normalize event weights
 ($\braket{\ldots}$ denotes the average):
 \begin{enumerate}
 \item $\braket{w_i} = 1$, \qquad\qquad $\Braket{\sum_i w_i} = N$
 \item $\braket{w_i} = \sigma$, \qquad\qquad $\Braket{\sum_i w_i} = N
   \times \sigma$
 \item $\braket{w_i} = 1/N$, \quad\qquad $\Braket{\sum_i w_i} = 1$
 \item $\braket{w_i} = \sigma/N$, \quad\qquad $\Braket{\sum_i w_i} = \sigma$
 \end{enumerate}
 So the four options are to have the average weight equal to unity, to
 the cross section of the corresponding process, to one over the number
 of events, or the cross section over the event calls. In these four
 cases, the event weights sum up to the event number, the event number
 times the cross section, to unity, and to the cross section,
 respectively. Note that neither of these really guarantees that all
 event weights individually lie in the interval $0 \leq w_i \leq 1$.
 
 The user can steer the normalization of events by using in \sindarin\
 input files the string variable \ttt{\$sample\_normalization}. The default is
 \ttt{\$sample\_normalization = "auto"}, which uses option 1 for
 unweighted and 2 for weighted events, respectively. Note that this is
 also what the Les Houches Event Format (LHEF) demands for both types
 of events. This is \whizard's preferred mode, also for the reason, that
 event normalizations are independent from the number of events. Hence,
 event samples can be cut or expanded without further need to adjust
 the normalization. The unit normalization (option 1) can be switched
 on also for weighted events by setting the event normalization
 variable equal to \ttt{"1"}. Option 2 can be demanded
 by setting \ttt{\$sample\_normalization = "sigma"}. Options 3 and 4 can
 be set by \ttt{"1/n"} and \ttt{"sigma/n"}, respectively. \whizard\
 accepts small and capital letters for these expressions.
 
 In the following section we show some examples when discussing the
 different event formats available in \whizard.
 
 %%%%%%%%%
 
 \section{Event selection}
 
 The \ttt{selection} expression (cf.\ Sec.~\ref{subsec:analysis})
 reduces the event sample during generation or rescanning, selecting
 only events for which the expression evaluates to \ttt{true}.  Apart
 from internal analysis, the selection also applies to writing external
 files.  For instance, the following code generates a $e^+e^-\to
 W^+W^-$ sample with longitudinally polarized $W$ bosons only:
 \begin{footnotesize}
 \begin{verbatim}
 process ww = "e+", "e-" => "W-", "W+"
 polarized "W+"
 polarized "W-"
 ?polarized_events = true
 sqrts = 500
 selection = all Hel == 0 ["W+":"W-"]
 simulate (ww) { n_events = 1000 }
 \end{verbatim}
 \end{footnotesize}
 The number of events that end up in the sample on file is equal to the
 number of events with longitudinally polarized $W$s in the generated
 sample, so the file will contain less than 1000 events.
 
 
 %%%%%%%%%
 
 \section{Supported event formats}
 \label{sec:eventformats}
 
 Event formats can either be distinguished whether they are plain
 text (i.e. ASCII) formats or binary formats. Besides this, one can
 classify event formats according to whether they are natively
 supported by \whizard\ or need some external program or library to be
 linked. Table~\ref{tab:eventformats} gives a complete list of all
 event formats available in \whizard. The second column shows whether
 these are ASCII or binary formats, the third column contains brief
 remarks about the corresponding format, while the last column tells
 whether external programs or libraries are needed (which is the case
 only for the HepMC formats).
 
 \begin{table}
   \begin{center}
     \begin{tabular}{|l||l|l|r|}\hline
       Format & Type & remark & ext. \\\hline
       ascii & ASCII & \whizard\ verbose format & no
       \\
       Athena & ASCII & variant of HEPEVT & no
       \\
       debug & ASCII & most verbose \whizard\ format & no
       \\
       evx   & binary & \whizard's home-brew & no
       \\
       HepMC & ASCII & HepMC format & yes
       \\
       HEPEVT & ASCII & \whizard~1 style & no
       \\
       LCIO & ASCII & LCIO format & yes
       \\
       LHA  & ASCII & \whizard~1/old Les Houches style &no
       \\
       LHEF & ASCII & Les Houches accord compliant & no
       \\
       long & ASCII & variant of HEPEVT & no
       \\
       mokka & ASCII & variant of HEPEVT & no
       \\
       short & ASCII & variant of HEPEVT & no
       \\
       StdHEP (HEPEVT) & binary & based on HEPEVT common block  & no
       \\
       StdHEP (HEPRUP/EUP) & binary & based on HEPRUP/EUP common block
       & no \\
       Weight stream & ASCII & just weights & no \\
       \hline
     \end{tabular}
   \end{center}
   \caption{\label{tab:eventformats}
     Event formats supported by \whizard, classified according to
     ASCII/binary formats and whether an external program or library is
     needed to generate a file of this format. For both the HEPEVT and
     the LHA format there is a more verbose variant.
   }
 \end{table}
 The "\ttt{.evx}'' is \whizard's native binary event format. If you
 demand event generation and do not specify anything further, \whizard\
 will write out its events exclusively in this binary format. So in the
 examples discussed in the previous chapters (where we omitted all
 details about event formats), in all cases this and only this internal
 binary format has been generated. The generation of this raw format
 can be suppressed (e.g. if you want to have only one specific event
 file type) by setting the variable \verb|?write_raw = false|. However,
 if the raw event file is not present, \whizard\ is not able to re-use
 existing events (e.g. from an ASCII file) and will regenerate events
 for a given process. Note that from version v2.2.0 of \whizard\ on,
 the program is able to (partially) reconstruct complete events also
 from other formats than its internal format (e.g. LHEF), but this is
 still under construction and not yet complete.
 
 Other event formats can be written out by setting the variable
 \ttt{sample\_format = <format>}, where \ttt{<format>} can be any of
 the following supported variables:
 \begin{itemize}
 \item \ttt{ascii}: a quite verbose ASCII format which contains lots of
   information (an example is shown in the appendix). \newline
   Standard suffix: \ttt{.evt}
 \item \ttt{debug}: an even more verbose ASCII format intended for
   debugging which prints out also information about the internal data
   structures \newline
   Standard suffix: \ttt{.debug}
 \item \ttt{hepevt}: ASCII format that writes out a specific
   incarnation of the HEPEVT common block (\whizard~1
   back-compatibility) \newline
   Standard suffix: \ttt{.hepevt}
 \item \ttt{hepevt\_verb}: more verbose version of \ttt{hepevt} (\whizard~1
   back-compatibility) \newline
   Standard suffix: \ttt{.hepevt.verb}
 \item \ttt{short}: abbreviated variant of the previous HEPEVT (\whizard\
   1 back-compatibility)  \newline
   Standard suffix: \ttt{.short.evt}
 \item \ttt{long}: HEPEVT variant that contains a little bit more
   information than the short format but less than HEPEVT (\whizard\
   1 back-compatibility)  \newline
   Standard suffix: \ttt{.long.evt}
 \item \ttt{athena}: HEPEVT variant suitable for read-out in the ATLAS
   ATHENA software environment (\whizard\
   1 back-compatibility)  \newline
   Standard suffix: \ttt{.athena.evt}
 \item \ttt{mokka}: HEPEVT variant suitable for read-out in the MOKKA
   ILC software environment \newline
   Standard suffix: \ttt{.mokka.evt}
 \item \ttt{lcio}: LCIO ASCII format (only available if LCIO is
   installed and correctly linked) \newline
   Standard suffix: \ttt{.lcio}
 \item \ttt{lha}: Implementation of the Les Houches Accord as it was in
   the old MadEvent and \whizard~1 \newline
   Standard suffix: \ttt{.lha}
 \item \ttt{lha\_verb}: more verbose version of \ttt{lha} \newline
   Standard suffix: \ttt{.lha.verb}
 \item \ttt{lhef}: Formatted Les Houches Accord implementation that
   contains the XML headers \newline
   Standard suffix: \ttt{.lhe}
 \item \ttt{hepmc}: HepMC ASCII format (only available if HepMC is
   installed and correctly linked) \newline
   Standard suffix: \ttt{.hepmc}
 \item \ttt{stdhep}: StdHEP binary format based on the HEPEVT common
   block
   \newline
   Standard suffix: \ttt{.hep}
 \item \ttt{stdhep\_up}: StdHEP binary format based on the HEPRUP/HEPEUP
   common blocks
   \newline
   Standard suffix: \ttt{.up.hep}
 \item \ttt{stdhep\_ev4}: StdHEP binary format based on the HEPEVT/HEPEV4
   common blocks
   \newline
   Standard suffix: \ttt{.ev4.hep}
 \item \ttt{weight\_stream}: Format that prints out only the event
   weight (and maybe alternative ones) \newline
   Standard suffix: \ttt{.weight.dat}
 \end{itemize}
 Of course, the variable \ttt{sample\_format} can contain more than one
 of the above identifiers, in which case more  than one different event
 file format is generated. The list above also shows the standard
 suffixes for these event formats (remember, that the native binary
 format of \whizard\ does have the suffix \ttt{.evx}). (The suffix of
 the different event formats can even be changed by the user by setting
 the corresponding variable \ttt{\$extension\_lhef = "foo"} or
 \ttt{\$extension\_ascii\_short = "bread"}. The dot is automatically
 included.)
 
 The name of the corresponding event sample is taken to be the string
 of the name of the first process in the \ttt{simulate}
 statement. Remember, that conventionally the events for all processes
 in one \ttt{simulate} statement will be written into one single event
 file. So \ttt{simulate (proc1, proc2)} will write events for the two
 processes \ttt{proc1} and \ttt{proc2} into one single event file with
 name \ttt{proc1.evx}. The name can be changed by the user with the
 command \ttt{\$sample = "<name>"}.
 
 The commands \ttt{\$sample} and \ttt{sample\_format} are both accepted
 as optional arguments of a \ttt{simulate} command, so e.g.
 \ttt{simulate (proc) \{ \$sample = "foo" sample\_format = hepmc \}}
 generates an event sample in the HepMC format for the process
 \ttt{proc} in the file \ttt{foo.hepmc}.
 
 Examples for event formats, for specifications of the
 event formats correspond the different accords and publicatios:
 
 {\bf HEPEVT:}
 
 The HEPEVT is an ASCII event format that does not contain an event
 file header. There is a one-line header for each single event,
 containing four entries. The number of particles in the event
 (\ttt{ISTHEP}), which is four for a fictitious example process $hh\to
 hh$, but could be larger if e.g. beam remnants are demanded to be included in the
 event. The second entry and third entry are the number of outgoing
 particles and beam remnants, respectively. The event weight is the
 last entry. For each particle in the event there are three lines:
 the first one is the status according to the HEPEVT format,
 \ttt{ISTHEP}, the second one the PDG code, \ttt{IDHEP}, then there are
 the one or two possible mother particle, \ttt{JMOHEP}, the first and
 last possible daughter particle, \ttt{JDAHEP}, and the polarization.
 The second line contains the three momentum components, $p_x$, $p_y$,
 $p_z$, the particle energy $E$, and its mass, $m$.
 The last line contains the position of the vertex in the event
 reconstruction.
 
 \begin{scriptsize}
   \begin{verbatim}
  4 2 0  3.0574068604E+08
  2 25 0 0 3 4 0
   0.0000000000E+00  0.0000000000E+00  4.8412291828E+02  5.0000000000E+02  1.2500000000E+02
   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
  2 25 0 0 3 4 0
   0.0000000000E+00  0.0000000000E+00 -4.8412291828E+02  5.0000000000E+02  1.2500000000E+02
   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
  1 25 1 2 0 0 0
  -1.4960220911E+02 -4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02
   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
  1 25 1 2 0 0 0
   1.4960220911E+02  4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02
   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
   \end{verbatim}
 \end{scriptsize}
 
 {\bf ASCII SHORT:}
 
 This is basically the same as the HEPEVT standard, but very much
 abbreviated. The header line for each event is identical, but the first
 line per particle does only contain the PDG and the polarization,
 while the vertex information line is omitted.
 
 \begin{scriptsize}
   \begin{verbatim}
  4 2 0  3.0574068604E+08
  25 0
   0.0000000000E+00  0.0000000000E+00  4.8412291828E+02  5.0000000000E+02  1.2500000000E+02
  25 0
   0.0000000000E+00  0.0000000000E+00 -4.8412291828E+02  5.0000000000E+02  1.2500000000E+02
  25 0
  -1.4960220911E+02 -4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02
  25 0
   1.4960220911E+02  4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02
   \end{verbatim}
 \end{scriptsize}
 
 {\bf ASCII LONG:}
 
 Identical to the ASCII short format, but after each event there is a
 line containg two values: the value of the sample function to be
 integrated over phase space, so basically the squared matrix element
 including all normalization factors, flux factor, structure functions
 etc.
 
 \begin{scriptsize}
   \begin{verbatim}
  4 2 0  3.0574068604E+08
  25 0
   0.0000000000E+00  0.0000000000E+00  4.8412291828E+02  5.0000000000E+02  1.2500000000E+02
  25 0
   0.0000000000E+00  0.0000000000E+00 -4.8412291828E+02  5.0000000000E+02  1.2500000000E+02
  25 0
  -1.4960220911E+02 -4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02
  25 0
   1.4960220911E+02  4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02
   1.0000000000E+00  1.0000000000E+00
   \end{verbatim}
 \end{scriptsize}
 
 {\bf ATHENA:}
 
 Quite similar to the HEPEVT ASCII format. The header line, however,
 does contain only two numbers: an event counter, and the number of
 particles in the event. The first line for each particle lacks the
 polarization information (irrelevant for the ATHENA environment), but
 has as leading entry an ordering number counting the particles in the
 event. The vertex information line has only the four relevant position
 entries.
 
 
 \begin{scriptsize}
   \begin{verbatim}
  0 4
  1 2 25 0 0 3 4
   0.0000000000E+00  0.0000000000E+00  4.8412291828E+02  5.0000000000E+02  1.2500000000E+02
   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
  2 2 25 0 0 3 4
   0.0000000000E+00  0.0000000000E+00 -4.8412291828E+02  5.0000000000E+02  1.2500000000E+02
   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
  3 1 25 1 2 0 0
  -1.4960220911E+02 -4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02
   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
  4 1 25 1 2 0 0
   1.4960220911E+02  4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02
   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
   \end{verbatim}
 \end{scriptsize}
 
 {\bf MOKKA:}
 
 Quite similar to the ASCII short format, but the event entries are the
 particle status, the PDG code, the first and last daughter, the
 three spatial components of the momentum, as well as the mass.
 
 \begin{scriptsize}
 \begin{verbatim}
  4 2 0  3.0574068604E+08
  2 25 3 4  0.0000000000E+00  0.0000000000E+00  4.8412291828E+02  1.2500000000E+02
  2 25 3 4  0.0000000000E+00  0.0000000000E+00 -4.8412291828E+02  1.2500000000E+02
  1 25 0 0 -1.4960220911E+02 -4.6042825611E+02  0.0000000000E+00  1.2500000000E+02
  1 25 0 0  1.4960220911E+02  4.6042825611E+02  0.0000000000E+00  1.2500000000E+02
 \end{verbatim}
 \end{scriptsize}
 
 {\bf LHA:}
 
 This is the implementation of the Les Houches Accord, as it was used
 in \whizard\ 1 and the old MadEvent. There is a first line containing
 six entries: 1. the number of particles in the event, \ttt{NUP},
 2. the subprocess identification index, \ttt{IDPRUP}, 3. the event
 weight, \ttt{XWGTUP}, 4. the scale of the process, \ttt{SCALUP},
 5. the value or status of $\alpha_{QED}$, \ttt{AQEDUP}, 6. the value
 for $\alpha_s$, \ttt{AQCDUP}. The next seven lines contain as many
 entries as there are particles in the event: the first one has the PDG
 codes, \ttt{IDUP}, the next two the first and second mother of the particles,
 \ttt{MOTHUP}, the fourth and fifth line the two color indices,
 \ttt{ICOLUP}, the next one the status of the particle, \ttt{ISTUP},
 and the last line the polarization information, \ttt{ISPINUP}.
 At the end of the event there are as lines for each particles with the
 counter in the event and the four-vector of the particle. For more
 information on this event format confer~\cite{LesHouches}.
 
 \begin{scriptsize}
   \begin{verbatim}
  25 25  5.0000000000E+02  5.0000000000E+02 -1 -1 -1 -1 3 1
   1.0000000000E-01  1.0000000000E-03  1.0000000000E+00 42
      4     1  3.0574068604E+08  1.000000E+03 -1.000000E+00 -1.000000E+00
     25    25    25    25
      0     0     1     1
      0     0     2     2
      0     0     0     0
      0     0     0     0
     -1    -1     1     1
      9     9     9     9
      1  5.0000000000E+02  0.0000000000E+00  0.0000000000E+00  4.8412291828E+02
      2  5.0000000000E+02  0.0000000000E+00  0.0000000000E+00 -4.8412291828E+02
      3  5.0000000000E+02 -1.4960220911E+02 -4.6042825611E+02  0.0000000000E+00
      4  5.0000000000E+02  1.4960220911E+02  4.6042825611E+02  0.0000000000E+00
   \end{verbatim}
 \end{scriptsize}
 
 {\bf LHEF:}
 
 This is the modern version of the Les Houches accord event format
 (LHEF), for the details confer the corresponding publication~\cite{LHEF}.
 
 \begin{scriptsize}
   \begin{verbatim}
 <LesHouchesEvents version="1.0">
 <header>
   <generator_name>WHIZARD</generator_name>
   <generator_version>2.8.3</generator_version>
 </header>
 <init>
  25 25  5.0000000000E+02  5.0000000000E+02 -1 -1 -1 -1 3 1
   1.0000000000E-01  1.0000000000E-03  1.0000000000E+00 42
 </init>
 <event>
  4 42  3.0574068604E+08  1.0000000000E+03 -1.0000000000E+00 -1.0000000000E+00
  25 -1 0 0 0 0  0.0000000000E+00  0.0000000000E+00  4.8412291828E+02  5.0000000000E+02  1.2500000000E+02  0.0000000000E+00  9.0000000000E+00
  25 -1 0 0 0 0  0.0000000000E+00  0.0000000000E+00 -4.8412291828E+02  5.0000000000E+02  1.2500000000E+02  0.0000000000E+00  9.0000000000E+00
  25 1 1 2 0 0 -1.4960220911E+02 -4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02  0.0000000000E+00  9.0000000000E+00
  25 1 1 2 0 0  1.4960220911E+02  4.6042825611E+02  0.0000000000E+00  5.0000000000E+02  1.2500000000E+02  0.0000000000E+00  9.0000000000E+00
 </event>
 </LesHouchesEvents>
   \end{verbatim}
 \end{scriptsize}
 
 Note that for the LHEF format, there are different versions according
 to the different stages of agreement. They can be addressed from
 within the \sindarin\ file by setting the string variable
 \ttt{\$lhef\_version} to one of (at the moment) three values:
 \ttt{"1.0"}, \ttt{"2.0"}, or \ttt{"3.0"}. The examples above
 corresponds (as is indicated in the header) to the version \ttt{"1.0"}
 of the LHEF format. Additional information in form of alternative
 squared matrix elements or event weights in the event are the most
 prominent features of the other two more advanced versions. For more
 details confer the literature.
 
 \vspace{.5cm}
 
 Sample files for the default ASCII format as well as for the debug
 event format are shown in the appendix.
 
 %%%%%%%%%
 
 \section[Interfaces to Parton Showers, Matching and
 Hadronization]{Interfaces to Parton Showers, Matching\\and
   Hadronization}
 
 This section describes the interfaces to the internal parton shower as
 well as the parton shower and hadronization routines from
 \pythia. Moreover, our implementation of the MLM matching making use
 of the parton showers is described. Sample \sindarin\ files are
 located in the \ttt{share/examples} directory.
 All input files come in two versions, one using the internal shower,
 ending in \ttt{W.sin}, and one using \pythia's shower, ending in
 \ttt{P.sin}. Thus we state all file names as ending with \ttt{X.sin},
 where \ttt{X} has to be replaced by either \ttt{W} or \ttt{P}.
 The input files include \ttt{EENoMatchingX.sin} and
 \ttt{DrellYanNoMatchingX.sin} for $e^+ e^- \to hadrons$ and $p\bar{p}
 \to Z$ without matching. The corresponding \sindarin\ files with
 matching enabled are \ttt{EEMatching2X.sin} to \ttt{EEMatching5X.sin}
 for $e^+ e^- \to hadrons$ with a different number of partons included
 in the matrix element and \ttt{DrallYanMatchingX.sin} for Drell-Yan
 with one matched emission.
 
 \subsection{Parton Showers and Hadronization}
 
 From version 2.1 onwards, \whizard\ contains an implementation of an
 analytic parton shower as presented in \cite{Kilian:2011ka}, providing
 the opportunity to perform the parton shower from whithin
 \whizard. Moreover, an interface to \pythia\ is included, which can be
 used to delegate the parton shower to \pythia. The same interface can
 be used to hadronize events using the generated events using \pythia's
 hadronization routines. Note that by \pythia's default, when
 performing initial-state radiation multiple interactions are included
 and when performing the hadronization hadronic decays are included. If
 required, these additional steps have to be switched off using the
 corresponding arguments for \pythia's \ttt{PYGIVE} routine vie the
 \ttt{\$ps\_PYTHIA\_PYGIVE} string.
 
 Note that from version 2.2.4 on the earlier flag
 \ttt{--enable-shower} flag has been abandoned, and there is only a
 flag to either compile or not compile the interally attached
 \pythia\ttt{6} package (\ttt{--enable-pythia6}) last release of
 the \fortran\ \pythia, v6.427) as well as the interface. It can be
 invoked by the following \sindarin\ keywords:\\[2ex]
 %
 \centerline{\begin{tabular}{|l|l|}
 \hline\ttt{?ps\_fsr\_active = true} & master switch for final-state
 parton showers\\\hline
 \ttt{?ps\_isr\_active = true} & master switch for initial-state parton
 showers\\\hline
 \ttt{?ps\_taudec\_active = true} & master switch for $\tau$ decays (at
 the moment only via \ttt{TAUOLA}\\\hline
 \ttt{?hadronization\_active = true} & master switch to enable
 hadronization\\\hline
 \ttt{\$shower\_method = "PYTHIA6"} & switch to use \pythiasix's parton
 shower instead of \\ &
  \whizard's own shower\\\hline
 \end{tabular}}\mbox{}
 
 \vspace{4mm}
 
 If either \ttt{?ps\_fsr\_active} or \ttt{?ps\_isr\_active} is set to \verb|true|, the
 event will be transferred to the internal shower routines or the \pythia\ data structures,
 and the chosen shower steps (initial- and final-state radiation) will be
 performed. If hadronization is enabled via the \ttt{?hadronization\_active} switch, \whizard\ will call \pythia's hadronization routine.
 The hadron\-ization can be applied to events showered using the internal shower or showered using \pythia's shower routines, as well as unshowered events.
 Any necessary transfer of event data to \pythia\ is automatically taken care of within \whizard's shower interface.
 The resulting (showered and/or hadronized) event will be transferred back to \whizard,
 the former final particles will be marked as intermediate. The
 analysis can be applied to a showered and/or hadronized event just
 like in the unshowered/unhadronized case. Any event file can be used
 and will contain the showered/hadronized event.
 
 Settings for the internal analytic parton shower are set via the following \sindarin\ variables:\\[2ex]
 \begin{description}
 \item[\ttt{ps\_mass\_cutoff}] The cut-off in virtuality, below
   which, partons are assumed to radiate no more. Used for both ISR and
   FSR. Given in $\mbox{GeV}$. (Default = 1.0)
 \item[\ttt{ps\_fsr\_lambda}] The value for $\Lambda$ used in
   calculating the value of the running coupling constant $\alpha_S$
   for Final State Radiation. Given in $\mbox{GeV}$. (Default = 0.29)
 \item[\ttt{ps\_isr\_lambda}] The value for $\Lambda$ used in
   calculating the value of the running coupling constant $\alpha_S$
   for Initial State Radiation. Given in $\mbox{GeV}$. (Default = 0.29)
 \item[\ttt{ps\_max\_n\_flavors}] Number of quark flavours taken
   into account during shower evolution. Meaningful choices are 3 to
   include $u,d,s$-quarks, 4 to include $u,d,s,c$-quarks and 5 to
   include $u,d,s,c,b$-quarks. (Default = 5)
 \item[\ttt{?ps\_isr\_alphas\_running}] Switch to decide between a
   constant $\alpha_S$, given by \ttt{ps\_fixed\_alphas}, and a
   running $\alpha_S$, calculated using \ttt{ps\_isr\_lambda} for
   ISR. (Default = true)
 \item[\ttt{?ps\_fsr\_alphas\_running}] Switch to decide between a
   constant $\alpha_S$, given by \ttt{ps\_fixed\_alphas}, and a
   running $\alpha_S$, calculated using \ttt{ps\_fsr\_lambda} for
   FSR. (Default = true)
 \item[\ttt{ps\_fixed\_alphas}] Fixed value of $\alpha_S$ for the
   parton shower. Used if either one of the variables
   \ttt{?ps\_fsr\_alphas\_running}
   or \ttt{?ps\_isr\_alphas\_running} are set to
   \verb|false|. (Default = 0.0)
 \item[\ttt{?ps\_isr\_angular\_ordered}] Switch for angular ordered
   ISR. (Default = true )\footnote{The FSR is always simulated with
     angular ordering enabled.}
 \item[\ttt{ps\_isr\_primordial\_kt\_width}] The width in
   $\mbox{GeV}$ of the Gaussian assumed to describe the transverse
   momentum of partons inside the proton. Other shapes are not yet
   implemented. (Default = 0.0)
 \item[\ttt{ps\_isr\_primordial\_kt\_cutoff}] The maximal transverse
   momentum in $\mbox{GeV}$ of a parton inside the proton. Used as a
   cut-off for the Gaussian. (Default = 5.0)
 \item[\ttt{ps\_isr\_z\_cutoff}] Maximal $z$-value in initial state
   branchings. (Default = 0.999)
 \item[\ttt{ps\_isr\_minenergy}] Minimal energy in $\mbox{GeV}$ of
   an emitted timelike or final parton. Note that the energy is not
   calculated in the labframe but in the center-of-mas frame of the two
   most initial partons resolved so far, so deviations may
   occur. (Default = 1.0)
 \item[\ttt{ps\_isr\_tscalefactor}] Factor for the starting scale in
   the initial state shower evolution. ( Default = 1.0 )
 \item[\ttt{?ps\_isr\_only\_onshell\_emitted\_partons}] Switch to
   allow only for on-shell emitted partons, thereby rejecting all
   possible final state parton showers starting from partons emitted
   during the ISR. (Default = false)
 \end{description}
 
 Settings for the \pythia\ are transferred using the following
 \sindarin\ variables:\\[2ex]
 \centerline{\begin{tabular}{|l|l|}
 \hline\ttt{?ps\_PYTHIA\_verbose} & if set to false, output from
 \pythia\ will be suppressed\\\hline
 \ttt{\$ps\_PYTHIA\_PYGIVE} & a string containing settings transferred
 to \pythia's \ttt{PYGIVE} subroutine.\\ & The format is explained in
 the \pythia\ manual. The limitation to 100 \\ & characters mentioned
 there does not apply here, the string is split \\ & appropriately
 before being transferred to \pythia.\\\hline
 \end{tabular}}\mbox{}
 
 \vspace{4mm}
 
 Note that the included version of \pythia\ uses \lhapdf\ for initial state
 radiation whenever this is available, but the PDF set has to be set
 manually in that case using the keyword \ttt{ps\_PYTHIA\_PYGIVE}.
 
 \subsection{Parton shower -- Matrix Element Matching}
 
 Along with the inclusion of the parton showers, \whizard\ includes an
 implementation of the MLM matching procedure. For a detailed
 description of the implemented steps see \cite{Kilian:2011ka}. The
 inclusion of MLM matching still demands some manual settings in the
 \sindarin\ file. For a given base process and a matching of $N$
 additional jets, all processes that can be obtained by attaching up to
 $N$ QCD splittings, either a quark emitting a gluon or a gluon
 splitting into two quarks ar two gluons, have to be manually specified
 as additional processes. These additional processes need to be
 included in the \ttt{simulate} statement along with the original
 process. The \sindarin\ variable \ttt{mlm\_nmaxMEjets} has to be
 set to the maximum number of additional jets $N$. Moreover additional
 cuts have to be specified for the additional processes.
 \begin{verbatim}
   alias quark = u:d:s:c
   alias antiq = U:D:S:C
   alias j = quark:antiq:g
 
   ?mlm_matching = true
   mlm_ptmin = 5 GeV
   mlm_etamax = 2.5
   mlm_Rmin = 1
 
   cuts = all Dist > mlm_Rmin [j, j]
          and all Pt > mlm_ptmin [j]
          and all abs(Eta) < mlm_etamax [j]
 \end{verbatim}
 Note that the variables \ttt{mlm\_ptmin}, \ttt{mlm\_etamax} and
 \ttt{mlm\_Rmin} are used by the matching routine. Thus, replacing the
 variables in the \ttt{cut} expression and omitting the assignment
 would destroy the matching procedure.
 
 The complete list of variables introduced to steer the matching procedure is as follows:
 \begin{description}
 \item[\ttt{?mlm\_matching\_active}] Master switch to enable MLM
   matching. (Default = false)
 \item[\ttt{mlm\_ptmin}] Minimal transverse momentum, also used in
   the definition of a jet
 \item[\ttt{mlm\_etamax}] Maximal absolute value of pseudorapidity
   $\eta$, also used in defining a jet
 \item[\ttt{mlm\_Rmin}] Minimal $\eta-\phi$ distance $R_{min}$
 \item[\ttt{mlm\_nmaxMEjets}] Maximum number of jets $N$
 \item[\ttt{mlm\_ETclusfactor}] Factor to vary the jet
   definition. Should be $\geq 1$ for complete coverage of phase
   space. (Default = 1)
 \item[\ttt{mlm\_ETclusminE}] Minimal energy in the variation of the
   jet definition
 \item[\ttt{mlm\_etaclusfactor}] Factor in the variation of the jet
   definition. Should be $\leq 1$ for complete coverage of phase
   space. (Default = 1)
 \item[\ttt{mlm\_Rclusfactor}] Factor in the variation of the jet
   definition. Should be $\ge 1$ for complete coverage of phase
   space. (Default = 1)
 \end{description}
 The variation of the jet definition is a tool to asses systematic
 uncertainties introduced by the matching procedure (See section 3.1 in
 \cite{Kilian:2011ka}).
 
 
 %%%%%%%%%
 
 \section{Rescanning and recalculating events}
 \label{sec:rescan}
 
 In the simplest mode of execution, \whizard\ handles its events at the
 point where they are generated.  It can apply event transforms such as
 decays or shower (see above), it can analyze the events, calculate and
 plot observables, and it can output them to file.  However, it is also
 possible to apply two different operations to those events in
 parallel, or to reconsider and rescan an event sample that has been
 previously generated.
 
 We first discuss the possibilities that \ttt{simulate} offers.  For
 each event, \whizard\ calculates the matrix element for the hard
 interaction, supplements this by Jacobian and phase-space factors in
 order to obtain the event weight, optionally applies a rejection step
 in order to gather uniformly weighted events, and applies the
 cuts and analysis setup.  We may ask about the event matrix element or
 weight, or the analysis result, that we would have obtained for a
 different setting.  To this end, there is an \ttt{alt\_setup} option.
 
 This option allows us to recalculate, event by event, the matrix
 element, weight, or analysis contribution with a different parameter
 set but identical kinematics.  For instance, we may evaluate a
 distribution for both zero and non-zero anomalous coupling \ttt{fw}
 and enter some observable in separate histograms:
 
 \begin{footnotesize}
 \begin{verbatim}
   simulate (some_proc) {
       fw = 0
       analysis = record hist1 (eval Pt [H])
     alt_setup = {
        fw = 0.01
        analysis = record hist2 (eval Pt [H])
     }
   }
 \end{verbatim}
 \end{footnotesize}
 
 In fact, the \ttt{alt\_setup} object is not restricted to a single
 code block (enclosed in curly braces) but can take a list of those,
 \begin{footnotesize}
 \begin{verbatim}
   alt_setup = { fw = 0.01 }, { fw = 0.02 }, ...
 \end{verbatim}
 \end{footnotesize}
 Each block provides the environment for a separate evaluation of the
 event data.  The generation of these events, i.e., their kinematics,
 is still steered by the primary environment.
 
 The \ttt{alt\_setup} blocks may modify various settings that affect the
 evaluation of an event, including physical parameters, PDF choice,
 cuts and analysis, output format, etc.  This must not (i.e., cannot)
 affect the kinematics of an event, so don't modify particle masses.
 When applying cuts, they can only reduce the generated event sample,
 so they apply on top of the primary cuts for the simulation.
 
 Alternatively, it is possible to \ttt{rescan} a sample that has been
 generated by a previous \ttt{simulate} command:
 \begin{footnotesize}
 \begin{verbatim}
   simulate (some_proc) { $sample = "my_events"
     analysis = record hist1 (eval Pt [H])
   }
   ?update_sqme = true
   ?update_weight = true
   rescan "my_events" (some_proc) {
     fw = 0.01
     analysis = record hist2 (eval Pt [H])
   }
   rescan "my_events" (some_proc) {
     fw = 0.05
     analysis = record hist3 (eval Pt [H])
   }
 \end{verbatim}
 \end{footnotesize}
 In more complicated situation, rescanning is more transparent and
 offers greater flexibility than doing all operations at the very point
 of event generation.
 
 Combining these features with the \ttt{scan} looping construct, we
 already cover a considerable range of applications.  (There are
 limitations due to the fact that \sindarin\ doesn't provide array
 objects, yet.)  Note that the \ttt{rescan} construct also allows
 for an \ttt{alt\_setup} option.
 
 You may generate a new sample by rescanning, for which you may choose
 any output format:
 \begin{footnotesize}
 \begin{verbatim}
   rescan "my_events" (some_proc) {
     selection = all Pt > 100 GeV [H]
     $sample = "new_events"
     sample_format = lhef
   }
 \end{verbatim}
 \end{footnotesize}
 
 The event sample that you rescan need not be an internal raw \whizard\
 file, as above.  You may rescan a LHEF file,
 \begin{footnotesize}
 \begin{verbatim}
   rescan "lhef_events" (proc) {
     $rescan_input_format = "lhef"
   }
 \end{verbatim}
 \end{footnotesize}
 This file may have any origin, not necessarily from \whizard.  To
 understand such an external file, \whizard\ must be able to
 reconstruct the hard process and match it to a process with a known
 name (e.g., \ttt{proc}), that has been defined in the \sindarin\ script
 previously.
 
 Within its limits, \whizard\ can thus be used for translating an event
 sample from one format to another format.
 
 There are three important switches that control the rescanning
 behavior.  They can be set or unset independently.
 \begin{itemize}
 \item \ttt{?update\_sqme} (default: false).
   If true, \whizard\ will recalculate the hard matrix element for each
   event.  When applying an analysis, the recalculated squared matrix
   element (averaged and summed over quantum numbers as usual) is
   available as the variable \ttt{sqme\_prc}.  This may be related to
   \ttt{sqme\_ref}, the corresponding
   value in the event file, if available.  (For the \ttt{alt\_env}
   option, this switch is implied.)
 \item \ttt{?update\_weight} (default: false).
   If true, \whizard\ will recalculate the event weight according to
   the current environment and apply this to the event.  In particular,
   the user may apply a \ttt{reweight} expression.  In an
   analysis, the new weight value is available as \ttt{weight\_prc}, to
   be related
   to \ttt{weight\_ref} from the sample.  The updated weight will be
   applied for histograms and averages.  An unweighted event sample
   will thus be transformed into a weighted event sample.  (This switch
   is also implied for the \ttt{alt\_env} option.)
 \item \ttt{?update\_event} (default: false).
   If true, \whizard\ will generate a new decay chain etc., if
   applicable.  That is, it reuses just the particles in the hard
   process.  Otherwise, the complete event is kept as it is written to
   file.
 \end{itemize}
 For these options to make sense, \whizard\ must have access to a full
 process object, so the \sindarin\ script must contain not just a
 definition but also a \ttt{compile} command for the matrix elements in
 question.
 
 If an event file (other than raw format) contains several processes as
 a mixture, they must be identifiable by a numeric ID.  \whizard\ will
 recognize the processes if their respective \sindarin\ definitions
 contain appropriate \ttt{process\_num\_id} options, such as
 \begin{footnotesize}
 \begin{verbatim}
   process foo = u, ubar => d, dbar { process_num_id = 42 }
 \end{verbatim}
 \end{footnotesize}
 
 Certain event-file formats, such as LHEF, support alternative
 matrix-element values or weights.  \whizard\ can thus write both
 original and
 recalculated matrix-element and weight values.
 Other formats support only a single
 event weight, so the \ttt{?update\_weight} option is necessary for a
 visible effect.
 
 External event files in formats such as LHEF, HepMC, or LCIO, also may
 carry information about the value of the strong coupling $\alpha_s$
 and the energy scale of each event.  This information will also be
 provided by \whizard\ when writing external event files.  When such an
 event file is rescanned, the user has the choice to either user the
 $\alpha_s$ value that \whizard\ defines in the current context (or the
 method for obtaining an event-specific running $\alpha_s$ value), or
 override this for each event by using the value in the event file.
 The corresponding parameter is \ttt{?use\_alphas\_from\_file}, which
 is false by default.  Analogously, the parameter
 \ttt{?use\_scale\_from\_file} may be set to override the scale
 definition in the current context.  Obviously, these settings
 influence matrix-element recalculation and therefore require
 \ttt{?update\_sqme} to be set in order to become operational.
 
 %%%%%%%%%
 
 \section{Negative weight events}
 For usage at NLO refer to Subsection~\ref{ss:fixedorderNLOevents}.
 In case, you have some other mechanism to produce events with negative
 weights (e.g. with the \ttt{weight = {\em <expr>}} command), keep in
 mind that you should activate \ttt{?negative\_weights = true} and
 \ttt{unweighted = false}.  The generation of unweighted events with
 varying sign (also known as events and counter events) is currently not
 supported.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \chapter{User Code Plug-Ins}
 \label{chap:user}
 
 {\color{red}
 Note that the user-code plug-in mechanism has been currently (for
 version 2.2.0) disabled, as the huge refactoring of the code between
 versions 2.1.X and 2.2.X has completely changed many of the
 interfaces. We plan to bring the interface for user code for spectra,
 structure functions and event shapes, cuts and observables back online
 as soon as possible, at latest for version 2.4.0.
 }
 
 \vspace{2cm}
 
 
 \section{The plug-in mechanism}
 
 The capabilities of \whizard\ and its \sindarin\ command
 language are not always sufficient to adapt to all users' needs.  To
 make the program more versatile, there are several spots in the
 workflow where the user may plug in his/her own code, to enhance or
 modify the default behavior.
 
 User code can be injected, without touching \whizard's source code, in
 the following places:
 \begin{itemize}
 \item
   Cuts, weights, analysis, etc.:
   \begin{itemize}
   \item
     Cut functions that operate on a whole subevent.
   \item
     Observable (e.g., event shapes) calculated from a whole subevent.
   \item
     Observable calculated for a particle or particle pair.
   \end{itemize}
 \item
   Spectra and structure functions.
 \end{itemize}
 Additional plug-in locations may be added in the future.
 
 User code is loaded dynamically by \whizard.  There are two
 possibilities:
 \begin{enumerate}
 \item
   The user codes the required procedures in one or more Fortran source
   files that are present in the working directory of the \whizard\
   program.  \whizard\ is called with the \ttt{-u} flag:
   \begin{quote}
     \ttt{whizard -u --user-src=\emph{user-source-code-file}} \ldots
   \end{quote}
   The file must have the extension \ttt{.f90}, and the file name must
   be specified without extension.
 
   There may be an arbitrary number of user source-code files.  The
   compilation is done in order of appearance.  If the name of the user
   source-code file is \ttt{user.f90}, the flag \ttt{--user-src} can
   be omitted.
 
   This tells the program to compile and dynamically link the code at
   runtime.  The basename of the linked library is \ttt{user}.
 
   If a compiled (shared) library with that name already exists, it is taken
   as-is.  If the
   user code changes or the library becomes invalid for other reasons,
   recompilation of the user-code files can be forced by the flag
   \ttt{--rebuild-user} or by the generic \ttt{-r} flag.
 \item
   The user codes and compiles the required procedures him/herself.
   They should be provided in form of a library, where the interfaces of
   the individual procedures follow C calling conventions and exactly
   match the required interfaces as described in the following
   sections.  The library must be compiled in such a way that it can be
   dynamically linked.  If the calling conventions are met, the actual
   user code may be written in any programming language.  E.g., it may
   be coded in Fortran, C, or C++ (with \ttt{extern(C)} specifications).
 
   \whizard\ is called with the \ttt{-u} flag and is
   given the name of the user library as
   \begin{quote}
     \ttt{whizard -u --user-lib=\emph{user-library-file}} \ldots
   \end{quote}
 \end{enumerate}
 The library file should either be a dynamically loadable (shared)
 library with appropriate extension (\ttt{.so} on Linux), or a libtool
 archive (\ttt{.la}).
 
 The user-provided procedures may have arbitrary names; the user just
 has to avoid clashes with procedures from the Fortran runtime library
 or from the operating-system environment.
 
 
 \section{Data Types Used for Communication}
 \label{sec:c_prt}
 
 Since the user-code interface is designed to be interoperable with C,
 it communicates with \whizard\ only via C-interoperable data types.
 The basic data types (Fortran: integer and real kinds) \ttt{c\_int}
 and \ttt{c\_double} are usually identical with the default kinds on
 the Fortran side.  If necessary, explicit conversion may be inserted.
 
 For transferring particle data, we are using a specific derived type
 \ttt{c\_prt\_t} which has the following content:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
   type, bind(C) :: c_prt_t
      integer(c_int) :: type
      integer(c_int) :: pdg
      integer(c_int) :: polarized
      integer(c_int) :: h
      real(c_double) :: pe
      real(c_double) :: px
      real(c_double) :: py
      real(c_double) :: pz
      real(c_double) :: p2
   end type c_prt_t
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The meaning of the entries is as follows:
 \begin{description}
 \item[\ttt{type}:] The type of the particle.  The common type
   codes are 1=incoming, 2=outgoing, and 3=composite.  A composite
   particle in a subevent is created from a combination of individual
   particle momenta, e.g., in jet clustering.  If the status code is
   not defined, it is set to zero.
 \item[\ttt{pdg}:] The particle identification code as proposed by the
   Particle Data Group.  If undefined, it is zero.
 \item[\ttt{polarized}:] If nonzero, the particle is polarized.  The
   only polarization scheme supported at this stage is helicity.  If
   zero, particle polarization is ignored.
 \item[\ttt{h}:] If the particle is polarized, this is the helicity.  $0$
   for a scalar, $\pm 1$ for a spin-1/2 fermion, $-1,0,1$ for a spin-1
   boson.
 \item[\ttt{pe}:] The energy in GeV.
 \item[\ttt{px}/\ttt{py}:] The transversal momentum components in GeV.
 \item[\ttt{pz}:] The longitudinal momentum component in GeV.
 \item[\ttt{p2}:] The invariant mass squared of the actual momentum in GeV$^2$.
 \end{description}
 \whizard\ does not provide tools for manipulating \ttt{c\_prt\_t}
 objects directly.  However, the four-momentum can be used in
 Lorentz-algebra calculations from the \ttt{lorentz} module.  To this
 end, this module defines the transformational functions
 \ttt{vector4\_from\_c\_prt} and \ttt{vector4\_to\_c\_prt}.
 
 
 \section{User-defined Observables and Functions}
 \subsection{Cut function}
 Instead of coding a cut expression in \sindarin, it may be coded in
 Fortran, or in any other language with a C-compatible interface.  A
 user-defined cut expression is referenced in \sindarin\ as follows:
 \begin{quote}
 \begin{footnotesize}
   \ttt{cuts = user\_cut (\emph{name-string}) [\emph{subevent}]}
 \end{footnotesize}
 \end{quote}
 The \ttt{\emph{name-string}} is an expression that evaluates to
 string, the name of the function to call in the user code.  The
 \emph{subevent} is a subevent expression, analogous to the built-in
 cut definition syntax.  The result of the \ttt{user\_cut} function is
 a logical value in \sindarin.  It is true if the event passes the cut,
 false otherwise.
 
 If coded in Fortran, the actual user-cut function in the user-provided
 source code has the following form:
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 function user_cut_fun (prt, n_prt) result (iflag) bind(C)
    use iso_c_binding
    use c_particles
    type(c_prt_t), dimension(*), intent(in) :: prt
    integer(c_int), intent(in) :: n_prt
    integer(c_int) :: iflag
    ! ... code that evaluates iflag
 end function user_cut_fun
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 Here, \ttt{user\_cut\_fun} can be replaced by an arbitrary name by
 which the function is referenced as \ttt{\emph{name-string}} above.
 The \ttt{bind(C)} attribute in the function declaration is mandatory.
 
 The argument \ttt{prt} is an array of objects of type \ttt{c\_prt\_t},
 as described above.  The integer \ttt{n\_prt} is the number of entries
 in the array.  It is passed separately in order to determine the
 actual size of the assumed-size \ttt{prt} array.
 
 The result \ttt{iflag} is an integer.  A nonzero value indicates
 \ttt{true} (i.e., the event passes the cut), zero value indicates
 \ttt{false}.  (We do not use boolean values in the interface because
 their interoperability might be problematic on some systems.)
 
 \subsection{Event-shape function}
 
 An event-shape function is similar to a cut function.  It takes a
 subevent as argument and returns a real (i.e., C double) variable.  It
 can be used for defining subevent observables, event weights, or the
 event scale, as in
 \begin{quote}
 \begin{footnotesize}
   \ttt{analysis = record \emph{hist-id} (user\_event\_fun (\emph{name-string}) [\emph{subevent}])}
 \end{footnotesize}
 \end{quote}
 or
 \begin{quote}
 \begin{footnotesize}
   \ttt{scale = user\_event\_fun (\emph{name-string}) [\emph{subevent}]}
 \end{footnotesize}
 \end{quote}
 The corresponding Fortran source code has the form
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 function user_event_fun (prt, n_prt) result (rval) bind(C)
    use iso_c_binding
    use c_particles
    type(c_prt_t), dimension(*), intent(in) :: prt
    integer(c_int), intent(in) :: n_prt
    real(c_double) :: rval
    ! ... code that evaluates rval
 end function user_event_fun
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 with \ttt{user\_event\_fun} replaced by \ttt{\emph{name-string}}.
 
 \subsection{Observable}
 
 In \sindarin, an observable-type function is a function of one or two
 particle objects that returns a real value.  The particle objects
 result from scanning over subevents.  In the \sindarin\ code, the
 observable is used like a variable; the particle-object arguments are
 implictly assigned.
 
 A user-defined observable is used analogously, e.g.,
 \begin{quote}
 \begin{footnotesize}
   \ttt{cuts = all user\_obs (\emph{name-string}) > 0 [\emph{subevent}]}
 \end{footnotesize}
 \end{quote}
 The user observable is defined, as Fortran code, as either a unary or
 as a binary C-double-valued function of \ttt{c\_prt\_t} objects.  The
 use in \sindarin\ (unary or binary) must match the definition.
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 function user_obs_unary (prt1) result (rval) bind(C)
   use iso_c_binding
   use c_particles
   type(c_prt_t), intent(in) :: prt1
   real(c_double) :: rval
   ! ... code that evaluates rval
 end function user_obs_unary
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 or
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 function user_obs_binary (prt1, prt2) result (rval) bind(C)
   use iso_c_binding
   use c_particles
   type(c_prt_t), intent(in) :: prt1, prt2
   real(c_double) :: rval
   ! ... code that evaluates rval
 end function user_obs_binary
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 with \ttt{user\_obs\_unary}/\ttt{binary} replaced by
 \ttt{\emph{name-string}}.
 
 \subsection{Examples}
 
 For an example, we implement three different ways of computing the
 transverse momentum of a particle.  This observable is actually
 built into \whizard, so the examples are not particularly useful.  However,
 implementing kinematical functions that are not supported (yet) by
 \whizard\ (and not easily computed via \sindarin\ expressions)
 proceeds along the same lines.
 
 \subsubsection{Cut}
 The first function is a complete cut which can be used as
 \begin{quote}
   \begin{footnotesize}
     \ttt{cuts = user\_cut("ptcut") [\emph{subevt}]}
   \end{footnotesize}
 \end{quote}
 It is equivalent to
 \begin{quote}
   \begin{footnotesize}
     \ttt{cuts = all Pt $>$ 50 [\emph{subevt}]}
   \end{footnotesize}
 \end{quote}
 The implementation reads
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 function ptcut (prt, n_prt) result (iflag) bind(C)
   use iso_c_binding
   use c_particles
   use lorentz
   type(c_prt_t), dimension(*), intent(in) :: prt
   integer(c_int), intent(in) :: n_prt
   integer(c_int) :: iflag
   logical, save :: first = .true.
   if (all (transverse_part (vector4_from_c_prt (prt(1:n_prt))) > 50)) then
      iflag = 1
   else
      iflag = 0
   end if
 end function ptcut
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 The procedure makes use of the kinematical functions in the
 \ttt{lorentz} module, after transforming the particles into a
 \ttt{vector4} array.
 
 \subsubsection{Event Shape}
 Similar functionality can be achieved by implementing an event-shape
 function.  The function computes the minimum $p_T$ among all particles
 in the subevent.  The \sindarin\ expression reads
 \begin{quote}
   \begin{footnotesize}
     \ttt{cuts = user\_event\_shape("pt\_min") [\emph{subevt}] $>$ 50}
   \end{footnotesize}
 \end{quote}
 and the function is coded as
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 function pt_min (prt, n_prt) result (rval) bind(C)
   use iso_c_binding
   use c_particles
   use lorentz
   type(c_prt_t), dimension(*), intent(in) :: prt
   integer(c_int), intent(in) :: n_prt
   real(c_double) :: rval
   rval = minval (transverse_part (vector4_from_c_prt (prt(1:n_prt))))
 end function pt_min
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 \subsubsection{Observable}
 The third (and probably simplest) user implementation of the $p_T$ cut
 computes a single-particle observable.  Here, the usage is
 \begin{quote}
   \begin{footnotesize}
     \ttt{cuts = all user\_obs("ptval") $>$ 50 [\emph{subevt}]}
   \end{footnotesize}
 \end{quote}
 and the subroutine reads
 \begin{quote}
 \begin{footnotesize}
 \begin{verbatim}
 function ptval (prt1) result (rval) bind(C)
   use iso_c_binding
   use c_particles
   use lorentz
   type(c_prt_t), intent(in) :: prt1
   real(c_double) :: rval
   rval = transverse_part (vector4_from_c_prt (prt1))
 end function ptval
 \end{verbatim}
 \end{footnotesize}
 \end{quote}
 
 \section{User Code and Static Executables}
 
 In Sec.~\ref{sec:static} we describe how to build a static executable that can
 be submitted to batch jobs, e.g., on the grid, where a compiler may not be
 available.
 
 If there is user plug-in code, it would require the same setup of
 libtool, compiler and linker on the target host, as physical process
 code.  To avoid this, it is preferable to link the user code
 statically with the executable, which is then run as a monolithic
 program.
 
 This is actually simple.  Two conditions have to be met:
 \begin{enumerate}
 \item
   The \whizard\ job that creates the executable has to be given the appropriate
   options (\ttt{-u}, \ttt{--user-src}, \ttt{--user-lib}) such that
   the user code is dynamically compiled and linked.
 \item
   The compile command in the \sindarin\ script which creates the
   executable takes options that list the procedures which the
   stand-alone program should access:
   \begin{quote}
     \begin{footnotesize}
 \ttt{%
 compile as "\emph{executable-name}" \{ \\
 \hspace*{2em}  \$user\_procs\_cut          = "\emph{cut-proc-names}"\\
 \hspace*{2em}  \$user\_procs\_event\_shape = "\emph{event-shape-proc-names}"\\
 \hspace*{2em}  \$user\_procs\_obs1         = "\emph{obs1-proc-names}"\\
 \hspace*{2em}  \$user\_procs\_obs2         = "\emph{obs2-proc-names}"\\
 \hspace*{2em}  \$user\_procs\_sf           = "\emph{strfun-names}"\\
 \}}
     \end{footnotesize}
   \end{quote}
   The values of these option variables are comma-separated lists of procedure
   names, grouped by their nature.  \ttt{obs1} and \ttt{obs2} refer to unary
   and binary observables, respectively.  The \ttt{strfun-names} are
   the names of the user-defined spectra or structure functions as they
   would appear in the \sindarin\ file which uses them.
 \end{enumerate}
 With these conditions met, the stand-alone executable will have the
 user code statically linked, and it will be able to use exactly those
 user-defined routines that have been listed in the various option
 strings.  (It is possible nevertheless, to plug in additional user code
 into the stand-alone executable, using the same options as for the
 original \whizard\ program.)
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \chapter{Data Visualization}
 \label{chap:visualization}
 
 \section{GAMELAN}
 
 The data values and tables that we have introduced in the previous section can
 be visualized using built-in features of \whizard.  To be precise,
 \whizard\ can write \LaTeX\ code which incorporates code in the graphics
 language GAMELAN to produce a pretty-printed account of observables,
 histograms, and plots.
 
 GAMELAN is a macro package for MetaPost, which is part of the
 \TeX/\LaTeX\ family.  MetaPost, a derivative of Knuth's MetaFont language for
 font design, is usually bundled with the \TeX\ distribution, but might need a
 separate switch for installation.  The GAMELAN macros are contained in a
 subdirectory of the \whizard\ package.  Upon installation, they will be
 installed in the appropriate directory, including the \ttt{gamelan.sty} driver
 for \LaTeX.  \whizard\ uses a subset of GAMELAN's graphics macros
 directly, but it allows for access to the full package if desired.
 
 An (incomplete) manual for GAMELAN can be found in the \ttt{share/doc}
 subdirectory of the \whizard\ system.  \whizard\ itself uses a subset of the
 GAMELAN capabilities, interfaced by \sindarin\ commands and parameters.  They
 are described in this chapter.
 
 To process analysis output beyond writing tables to file, the
 \ttt{write\_analysis} command described in the previous section should be
 replaced by \ttt{compile\_analysis}, with the same syntax:
 \begin{quote}
   \begin{footnotesize}
     \ttt{compile\_analysis (\emph{analysis-tags}) \{ \ttt{\emph{options}} \}}
   \end{footnotesize}
 \end{quote}
 where \ttt{\emph{analysis-tags}}, a comma-separated list of analysis objects,
 is optional.  If there are no tags, all analysis objects are processed.  The
 \ttt{\emph{options}} script of local commands is also optional, of course.
 
 This command will perform the following actions:
 \begin{enumerate}
 \item
   It writes a data file in default format, as \ttt{write\_analysis} would do.
   The file name is given by \ttt{\$out\_file}, if nonempty.  The file must not
   be already open, since the command needs a self-contained file, but the name
   is otherwise arbitrary.  If the value of \ttt{\$out\_file} is empty, the
   default file name is \ttt{whizard\_analysis.dat}.
 \item
   It writes a driver file for the chosen datasets, whose name is derived from
   the data file by replacing the file extension of the data file with the
   extension \ttt{.tex}.  The driver file is a \LaTeX\ source file which
   contains embedded GAMELAN code that handles the selected graphics data.  In
   the \LaTeX\ document, there is a separate section for each contained
   dataset. Furthermore, a process-/analysis-specific makefile with the
   name \ttt{<process\_name>\_ana.makefile} is created that can be used
   to generate postscript or PDF output from the \LaTeX\ source. If the
   steering flag \ttt{?analysis\_file\_only} is set to \ttt{true}, then
   the \LaTeX\ file and the makefile are only written, but no execution
   of the makefile resulting in compilation of the \LaTeX\ code (see
   the next item) is invoked.
 \item
   As mentioned above, if the flag \ttt{?analysis\_file\_only} is set
   to \ttt{false} (which is the default), the driver file is processed
   by \LaTeX (invoked by calling the makefile with the name
   \ttt{<process\_name>\_ana.makefile}), which generates an appropriate
   GAMELAN source file with extension \ttt{.mp}.  This code is executed
   (calling GAMELAN/MetaPost, and again \LaTeX\ for typesetting embedded
   labels).  There is a second \LaTeX\ pass (automatically done by the
   makefile) which collects the results, and finally conversion to
   PostScript and PDF formats.
 \end{enumerate}
 
 The resulting PostScript or PDF file -- the file name is the name of the data
 file with the extension replaced by \ttt{.ps} or \ttt{.pdf}, respectively
 -- can be printed or viewed with an appropriate viewer such as \ttt{gv}.  The
 viewing command is not executed automatically by \whizard.
 
 Note that \LaTeX\ will write further files with extensions \ttt{.log},
 \ttt{.aux}, and \ttt{.dvi}, and GAMELAN will produce auxiliary files with
 extensions \ttt{.ltp} and \ttt{.mpx}. The log file in particular, could
 overwrite \whizard's log file if the basename is identical.  Be careful to use
 a value for \ttt{\$out\_file} which is not likely to cause name clashes.
 
 
 \subsection{User-specific changes}
 
 In the case, that the \sindarin\ \ttt{compile\_analysis} command is
 invoked and the flag named \ttt{?analysis\_file\_only} is not changed
 from its default value \ttt{false}, \whizard\ calls the
 process-/analysis-specific makefile triggering the compilation of the
 \LaTeX\ code and the GAMELAN plots and histograms. If the user wants
 to edit the analysis output, for example changing captions, headlines,
 labels, properties of the plots, graphs and histograms using GAMELAN
 specials etc., this is possible and the output can be regenerated
 using the makefile. The user can also directly invoke the GAMELAN
 script, \ttt{whizard-gml}, that is installed in the binary directly
 along with the \whizard\ binary and other scripts. Note however, that
 the \LaTeX\ environment for the specific style files have to be set by
 hand (the command line invocation in the makefile does this
 automatically). Those style files are generally written into
 \ttt{share/texmf/whizard/} directory. The user can execute the
 commands in the same way as denoted in the process-/analysis-specific
 makefile by hand.
 
 
 %%%%%
 
 \section{Histogram Display}
 
 
 %%%%%
 
 \section{Plot Display}
 
 
 \section{Graphs}
 \label{sec:graphs}
 
 Graphs are an additional type of analysis object.  In contrast to histograms
 and plots, they do not collect data directly, but they rather act as
 containers for graph elements, which are copies of existing histograms and
 plots.  Their single purpose is to be displayed by the GAMELAN driver.
 
 Graphs are declared by simple assignments such as
 \begin{quote}
   \begin{footnotesize}
     \ttt{graph g1 = hist1}
 \\
     \ttt{graph g2 = hist2 \& hist3 \& plot1}
   \end{footnotesize}
 \end{quote}
 The first declaration copies a single histogram into the graph, the second one
 copies two histograms and a plot.  The syntax for collecting analysis objects
 uses the \ttt{\&} concatenation operator, analogous to string concatenation.
 In the assignment, the rhs must contain only histograms and plots.  Further
 concatenating previously declared graphs is not supported.
 
 After the graph has been declared, its contents can be written to file
 (\ttt{write\_analysis}) or, usually, compiledd by the \LaTeX/GAMELAN driver
 via the \ttt{compile\_analysis} command.
 
 The graph elements on the right-hand side of the graph assignment are copied
 with their current data content.  This implies a well-defined order of
 statements: first, histograms and plots are declared, then they are filled via
 \ttt{record} commands or functions, and finally they can be collected for
 display by graph declarations.
 
 A simple graph declaration without options as above is possible, but usually
 there are option which affect the graph display.  There are two kinds of
 options: graph options and drawing options.  Graph options apply to the graph
 as a whole (title, labels, etc.) and are placed in braces on the lhs of the
 assigment.  Drawing options apply to the individual graph elements
 representing the contained histograms and plots, and are placed together with
 the graph element on the rhs of the assignment.  Thus, the complete syntax for
 assigning multiple graph elements is
 \begin{quote}
   \begin{footnotesize}
     \ttt{graph \emph{graph-tag} \{ \emph{graph-options} \}}
 \\
     \ttt{= \emph{graph-element-tag1} \{ \emph{drawing-options1} \}}
 \\
     \ttt{\& \emph{graph-element-tag2} \{ \emph{drawing-options2} \}}
 \\
      \ldots
   \end{footnotesize}
 \end{quote}
 This form is recommended, but graph and drawing options can also be set as
 global parameters, as usual.
 
 We list the supported graph and drawing options in
 Tables~\ref{tab:graph-options} and \ref{tab:drawing-options}, respectively.
 
 \begin{table}
   \caption{Graph options.  The content of strings of type \LaTeX\ must be
     valid \LaTeX\ code (containing typesetting commands such as math mode).
     The content of strings of type GAMELAN must be valid GAMELAN code.
     If a graph bound is kept \emph{undefined}, the actual graph bound is
     determined such as not to crop the graph contents in the selected
     direction.}
   \label{tab:graph-options}
 
   \begin{center}
     \begin{tabular}{|l|l|l|l|}
       \hline
       Variable & Default & Type & Meaning
       \\
       \hline\hline
       \ttt{\$title}  & \ttt{""} & \LaTeX &
         Title of the graph = subsection headline
       \\
       \hline
       \ttt{\$description}  & \ttt{""} &  \LaTeX &
         Description text for the graph
       \\
       \hline
       \ttt{\$x\_label} & \ttt{""} & \LaTeX &
         $x$-axis label
       \\
       \hline
       \ttt{\$y\_label} & \ttt{""} & \LaTeX &
         $y$-axis label
       \\
       \hline
       \ttt{graph\_width\_mm} & 130 & Integer &
         graph width (on paper) in mm
       \\
       \hline
       \ttt{graph\_height\_mm} & 90 & Integer &
         graph height (on paper) in mm
       \\
       \hline
       \ttt{?x\_log} & false & Logical &
         Whether the $x$-axis scale is linear or logarithmic
       \\
       \hline
       \ttt{?y\_log} & false & Logical &
         Whether the $y$-axis scale is linear or logarithmic
       \\
       \hline
       \ttt{x\_min} & \emph{undefined} & Real &
         Lower bound for the $x$ axis
       \\
       \hline
       \ttt{x\_max} & \emph{undefined} & Real &
         Upper bound for the $x$ axis
       \\
       \hline
       \ttt{y\_min} & \emph{undefined} & Real &
         Lower bound for the $y$ axis
       \\
       \hline
       \ttt{y\_max} & \emph{undefined} & Real &
         Upper bound for the $y$ axis
       \\
       \hline
       \ttt{gmlcode\_bg} & \ttt{""} & GAMELAN &
          Code to be executed before drawing
       \\
       \hline
       \ttt{gmlcode\_fg} & \ttt{""} & GAMELAN &
          Code to be executed after drawing
       \\
       \hline
     \end{tabular}
   \end{center}
 \end{table}
 
 \begin{table}
   \caption{Drawing options.  The content of strings of type GAMELAN must be
     valid GAMELAN code.  The behavior w.r.t. the flags with \emph{undefined}
     default value depends on the type of graph element.  Histograms: draw
     baseline, piecewise, fill area, draw curve, no errors, no symbols;  Plots:
     no baseline, no fill, draw curve, no errors, no symbols.}
   \label{tab:drawing-options}
 
   \begin{center}
     \begin{tabular}{|l|l|l|l|}
       \hline
       Variable & Default & Type & Meaning
       \\
       \hline\hline
       \ttt{?draw\_base}  & \emph{undefined} & Logical &
         Whether to draw a baseline for the curve
       \\
       \hline
       \ttt{?draw\_piecewise}  & \emph{undefined} & Logical &
         Whether to draw bins separately (histogram)
       \\
       \hline
       \ttt{?fill\_curve}  & \emph{undefined} & Logical &
         Whether to fill area between baseline and curve
       \\
       \hline
       \ttt{\$fill\_options} & \ttt{""} & GAMELAN &
         Options for filling the area
       \\
       \hline
       \ttt{?draw\_curve} & \emph{undefined} & Logical &
         Whether to draw the curve as a line
       \\
       \hline
       \ttt{\$draw\_options} & \ttt{""} & GAMELAN &
         Options for drawing the line
       \\
       \hline
       \ttt{?draw\_errors} & \emph{undefined} & Logical &
         Whether to draw error bars for data points
       \\
       \hline
       \ttt{\$err\_options} & \ttt{""} & GAMELAN &
         Options for drawing the error bars
       \\
       \hline
       \ttt{?draw\_symbols} & \emph{undefined} & Logical &
         Whether to draw symbols at data points
       \\
       \hline
       \ttt{\$symbol} & Black dot & GAMELAN &
         Symbol to be drawn
       \\
       \hline
       \ttt{gmlcode\_bg} & \ttt{""} & GAMELAN &
          Code to be executed before drawing
       \\
       \hline
       \ttt{gmlcode\_fg} & \ttt{""} & GAMELAN &
          Code to be executed after drawing
       \\
       \hline
     \end{tabular}
   \end{center}
 \end{table}
 
 
 \section{Drawing options}
 
 The options for coloring lines, filling curves, or choosing line styles make
 use of macros in the GAMELAN language.  At this place, we do not intend to
 give a full account of the possiblities, but we rather list a few basic
 features that are likely to be useful for drawing graphs.
 
 
 \subsubsection{Colors}
 
 GAMELAN knows about basic colors identified by name:
 \begin{center}
   \ttt{black}, \ttt{white}, \ttt{red}, \ttt{green}, \ttt{blue}, \ttt{cyan},
   \ttt{magenta}, \ttt{yellow}
 \end{center}
 More generically, colors in GAMELAN are RGB triplets of numbers (actually,
 numeric expressions) with values between 0 and 1, enclosed in brackets:
 \begin{center}
   \ttt{(\emph{r}, \emph{g}, \emph{b})}
 \end{center}
 
 To draw an object in color, one should apply the construct \ttt{withcolor
   \emph{color}} to its drawing code.  The default color is always black.
 Thus, this will make a plot drawn in blue:
 \begin{quote}
   \begin{footnotesize}
     \ttt{\$draw\_options = "withcolor blue"}
   \end{footnotesize}
 \end{quote}
 and this will fill the drawing area of some histogram with an RGB color:
 \begin{quote}
   \begin{footnotesize}
     \ttt{\$fill\_options = "withcolor (0.8, 0.7, 1)"}
   \end{footnotesize}
 \end{quote}
 
 
 \subsubsection{Dashes}
 
 By default, lines are drawn continuously.  Optionally, they can be drawn using
 a \emph{dash pattern}.  Predefined dash patterns are
 \begin{center}
   \ttt{evenly}, \ttt{withdots}, \ttt{withdashdots}
 \end{center}
 Going beyond the predefined patterns, a generic dash pattern has the syntax
 \begin{center}
   \ttt{dashpattern (on \emph{l1} off \emph{l2} on} \ldots \ttt{)}
 \end{center}
 with an arbitrary repetition of \ttt{on} and \ttt{off} clauses.  The numbers
 \ttt{\emph{l1}}, \ttt{\emph{l2}}, \ldots\ are lengths measured in pt.
 
 To apply a dash pattern, the option syntax \ttt{dashed \emph{dash-pattern}}
 should be used.  Options strings can be concatenated.  Here is how to draw in
 color with dashes:
 \begin{quote}
   \begin{footnotesize}
     \ttt{\$draw\_options = "withcolor red dashed evenly"}
   \end{footnotesize}
 \end{quote}
 and this draws error bars consisting of intermittent dashes and
 dots:
 \begin{quote}
   \begin{footnotesize}
     \ttt{\$err\_options = "dashed (withdashdots scaled 0.5)"}
   \end{footnotesize}
 \end{quote}
 The extra brackets ensure that the scale factor $1/2$ is applied only the dash
 pattern.
 
 
 \subsubsection{Hatching}
 
 Areas (e.g., below a histogram) can be filled with plain colors by the
 \ttt{withcolor} option.  They can also be hatched by stripes, optionally
 rotated by some angle.  The syntax is completely analogous to dashes.  There
 are two predefined \emph{hatch patterns}:
 \begin{center}
    \ttt{withstripes}, \ttt{withlines}
 \end{center}
 and a generic hatch pattern is written
 \begin{center}
   \ttt{hatchpattern (on \emph{w1} off \emph{w2} on} \ldots \ttt{)}
 \end{center}
 where the numbers \ttt{\emph{l1}}, \ttt{\emph{l2}}, \ldots\ determine the
 widths of the stripes, measured in pt.
 
 When applying a hatch pattern, the pattern may be rotated by some angle (in
 degrees) and scaled.  This looks like
 \begin{quote}
   \begin{footnotesize}
     \ttt{\$fill\_options = "hatched (withstripes scaled 0.8 rotated 60)"}
   \end{footnotesize}
 \end{quote}
 
 
 \subsubsection{Smooth curves}
 
 Plot points are normally connected by straight lines.  If data are acquired by
 statistical methods, such as Monte Carlo integration, this is usually
 recommended.  However, if a plot is generated using an analytic mathematical
 formula, or with sufficient statistics to remove fluctuations, it might be
 appealing to connect lines by some smooth interpolation.  GAMELAN can switch
 on spline interpolation by the specific drawing option \ttt{linked smoothly}.
 Note that the results can be surprising if the data points do have sizable
 fluctuations or sharp kinks.
 
 
 \subsubsection{Error bars}
 
 Plots and histograms can be drawn with error bars.  For histograms, only
 vertical error bars are supported, while plot points can have error bars in
 $x$ and $y$ direction.  Error bars are switched on by the \ttt{?draw\_errors}
 flag.
 
 There is an option to draw error bars with ticks: \ttt{withticks} and an
 alternative option to draw arrow heads: \ttt{witharrows}.  These can be used
 in the \ttt{\$err\_options} string.
 
 
 \subsubsection{Symbols}
 
 To draw symbols at plot points (or histogram midpoints), the flag
 \ttt{?draw\_symbols} has to be switched on.
 
 
 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{User Interfaces for WHIZARD}
 \label{chap:userint}
 
 \section{Command Line and \sindarin\ Input Files}
 \label{sec:cmdline-options}
 
 The standard way of using \whizard\ involves a command script written
 in \sindarin.  This script is executed by \whizard\ by mentioning it
 on the command line:
 \begin{interaction}
   whizard script-name.sin
 \end{interaction}
 You may specify several script files on the command line; they will be
 executed consecutively.
 
 If there is no script file, \whizard\ will read commands from standard
 input.  Hence, this is equivalent:
 \begin{interaction}
   cat script-name.sin | whizard
 \end{interaction}
 
 When executed from the command line, \whizard\ accepts several options.
 They are given in long form, i.e., they begin with two dashes.  Values
 that belong to options follow the option string, separated either by
 whitespace or by an equals sign.  Hence, \ttt{--prefix /usr} and
 \ttt{--prefix=/usr} are equivalent.  Some options are also available
 in short form, a single dash with a single letter.  Short-form options
 can be concatenated, i.e., a dash followed by several option letters.
 
 The first set of options is intended for normal operation.
 \begin{description}
 \item[\ttt{--debug AREA}]: Switch on debug output for \ttt{AREA}.
   \ttt{AREA} can be one of \whizard's source directories or \ttt{all}.
 \item[\ttt{--debug2 AREA}]: Switch on more verbose debug output for \ttt{AREA}.
 \item[\ttt{--single-event}]: Only compute one phase-space point (for debugging).
 \item[\ttt{--execute COMMANDS}]:  Execute \ttt{COMMANDS} as a script
-  before the script file.  Short version: \ttt{-e}
+  before the script file (see below).  Short version: \ttt{-e}
+\item[\ttt{--file CMDFILE}]:  Execute commands in \ttt{CMDFILE} before the
+  main script file (see below).  Short version: \ttt{-f} 
 \item[\ttt{--help}]:  List the available options and exit.  Short version:
   \ttt{-h}
 \item[\ttt{--interactive}]:  Run \whizard\ interactively.  See
   Sec.~\ref{sec:whish}.  Short version: \ttt{-i}.
 \item[\ttt{--library LIB}]:  Preload process library \ttt{LIB}
   (instead of the default \ttt{processes}).  Short version: \ttt{-l}.
 \item[\ttt{--localprefix DIR}]:  Search in \ttt{DIR} for local
   models.  Default is \ttt{\$HOME/.whizard}.
 \item[\ttt{--logfile \ttt{FILE}}]: Write log to \ttt{FILE}.  Default is
   \ttt{whizard.log}.  Short version: \ttt{-L}.
 \item[\ttt{--logging}]: Start logging on startup (default).
 \item[\ttt{--model MODEL}]: Preload model \ttt{MODEL}.  Default is the
   Standard Model \ttt{SM}.  Short version: \ttt{-m}.
 \item[\ttt{--no-banner}]: Do not display banner at startup.
 \item[\ttt{--no-library}]: Do not preload a library.
 \item[\ttt{--no-logfile}]: Do not write a logfile.
 \item[\ttt{--no-logging}]: Do not issue information into the logfile.
 \item[\ttt{--no-model}]: Do not preload a specific physics model.
 \item[\ttt{--no-rebuild}]: Do not force a rebuild.
 \item[\ttt{--query VARIABLE}]: Display documentation of \ttt{VARIABLE}.
   Short version: \ttt{-q}.
 \item[\ttt{--rebuild}]: Do not preload a process library and do all
   calculations from scratch, even if results exist.  This combines all
   rebuild options.  Short version: \ttt{-r}.
 \item[\ttt{--rebuild-library}]: Rebuild the process library, even if code
   exists.
 \item[\ttt{--rebuild-phase-space}]: Rebuild the phase space setup, even if
   it exists.
 \item[\ttt{--rebuild-grids}]: Redo the integration, even if previous grids
   and results exist.
 \item[\ttt{--rebuild-events}]: Redo event generation, discarding previous
   event files.
 \item[\ttt{--show-config}]: Show build-time configuration.
 \item[\ttt{--version}]: Print version information and exit.  Short version:
   \ttt{-V}.
 \item[-]: Any further options are interpreted as file names.
 \end{description}
 The second set of options refers to the configuration.  They are
 relevant when dealing with a relocated \whizard\ installation, e.g.,
 on a batch systems.
 \begin{description}
 \item[\ttt{--prefix DIR}]: Specify the actual location of the \whizard\
   installation, including all subdirectories.
 \item[\ttt{--exec-prefix DIR}]:  Specify the actual location of the
   machine-specific parts of the \whizard\ installation (rarely needed).
 \item[\ttt{--bindir DIR}]:  Specify the actual location of the
   executables contained in the \whizard\ installation (rarely needed).
 \item[\ttt{--libdir DIR}]:  Specify the actual location of the
   libraries contained in the \whizard\ installation (rarely needed).
 \item[\ttt{--includedir DIR}]:  Specify the actual location of the
   include files contained in the \whizard\ installation (rarely needed).
 \item[\ttt{--datarootdir DIR}]:  Specify the actual location of the
   data files contained in the \whizard\ installation (rarely needed).
 \item[\ttt{--libtool LOCAL\_LIBTOOL}]:  Specify the actual location and
   name of the \ttt{libtool} script that should be used by \whizard.
 \item[\ttt{--lhapdfdir DIR}]:  Specify the actual location and
   of the \lhapdf\ installation that should be used by \whizard.
 \end{description}
 
+The \ttt{--execute} and \ttt{--file} options allow for fine-tuning the command
+flow.  The \whizard\ main program will concatenate all commands given in
+\ttt{--execute} commands together with all commands contained in \ttt{--file}
+options, in the order they are encountered, as a contiguous command stream
+that is executed \emph{before} the main script (in the example above,
+\ttt{script-name.sin}).
+
+Regarding the \ttt{--execute} option, commands that contain blanks must be
+enclosed in matching single- or double-quote characters since the individual
+tokens would otherwise be intepreted as separate option strings.
+Unfortunately, a Unix/Linux shell interpreter will strip quotes before handing
+the command string over to the program.  In that situation, the
+quote-characters must be quoted themselves, or the string must be enclosed in
+quotes twice.  Either version should work as a command line interpreted by
+the shell:
+\begin{interaction}
+  whizard --execute \'int my_flag = 1\' script-name.sin
+  whizard --execute "'int my_flag = 1'" script-name.sin
+\end{interaction}
 
 
 \section{WHISH -- The \whizard\ Shell/Interactive mode}
 \label{sec:whish}
 
 \whizard\ can be also run in the interactive mode using its own shell
 environment. This is called the \whizard\ Shell (WHISH). For this
 purpose, one starts with the command
 \begin{interaction}
   /home/user$ whizard --interactive
 \end{interaction}
 or
 \begin{interaction}
   /home/user$ whizard -i
 \end{interaction}
 \whizard\ will preload the Standard Model and display a command
 prompt:
 \begin{interaction}
   whish?
 \end{interaction}
 You now can enter one or more \sindarin\ commands, just as if they
 were contained in a script file.  The commands are compiled and
 executed after you hit the ENTER key.  When done, you get a new
 prompt.  The WHISH can be closed by the \ttt{quit} command:
 \begin{verbatim}
   whish? quit
 \end{verbatim}
 Obviously, each input must be self-contained: commands must be
 complete, and conditionals or scans must be closed on the same line.
 
 If \whizard\ is run without options and without a script file, it
 also reads commands interactively, from standard input.  The
 difference is that in this case, interactive input is multi-line,
 terminated by \ttt{Ctrl-D}, the script is then compiled and
 executed as a whole, and \whizard\ terminates.
 
 In WHISH mode, each input line is compiled and executed individually.
 Furthermore, fatal errors are masked, so in case of error the program
 does not terminate but returns to the WHISH command line.  (The
 attempt to recover may fail in some circumstances, however.)
 
 
 \section{Graphical user interface}
 
 \emph{This is still experimental.}
 
 \whizard\ ships with a graphical interface that can be steered in a
 browser of your choice. It is located in \ttt{share/gui}.  To use it,
 you have to run \ttt{npm install} (which will install javascript
 libraries locally in that folder) and \ttt{npm start} (which will start
 a local web server on your machine) in that folder.  More technical
 details and how to get \ttt{npm} is discussed in
 \ttt{share/gui/README.md}.  When it is running, you can access the GUI
 by entering \ttt{localhost:3000} as address in your browser.  The GUI is
 separated into different tabs for basic settings, integration,
 simulation, cuts, scans, NLO and beams.  You can select and enter what
 you are interested in and the GUI will produce a \sindarin\ file.  You
 can use the GUI to run WHIZARD with that \sindarin\ or just produce it
 with the GUI and then tweak it further with an editor.  In case you run
 it in the GUI, the log file will be updated in the browser as it is
 produced.  Any \sindarin\ features that are not supported by the GUI can
 be added directly as "Additional Code".
 
 \section{WHIZARD as a library}
 
 \emph{This is planned, but not implemented yet.}
 %%%%%
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{Examples}
 \label{chap:examples}
 
 In this chapter we discuss the running and steering of \whizard\ with
 the help of several examples. These examples can be found in the
 \ttt{share/examples} directory of your installation. All of these
 examples are also shown on the \whizard\ Wiki page:
 \url{https://whizard.hepforge.org/trac/wiki}.
 
 
 \section{$Z$ lineshape at LEP I}
 
 By this example, we demonstrate how a scan over collision energies
 works, using as example the measurement of the $Z$ lineshape at LEP I
 in 1989. The \sindarin\ script for this example, \ttt{Z-lineshape.sin}
 can be found in the \ttt{share/examples} folder of the \whizard\
 installation.
 
 We first use the Standard model as physics model:
 \begin{code}
 model = SM
 \end{code}
 Aliases for electron, muon and their antiparticles as leptons and
 those including the photon as particles in general are introduced:
 \begin{code}
 alias lep = e1:E1:e2:E2
 alias prt = lep:A
 \end{code}
 Next, the two processes are defined, \eemm, and the same with an
 explicit QED photon: $e^+e^- \to \mu^+\mu^-\gamma$,
 \begin{code}
 process bornproc = e1, E1 => e2, E2
 process rc = e1, E1 => e2, E2, A
 compile
 \end{code}
 and the processes are compiled. Now, we define some very loose cuts to
 avoid singular regions in phase space, name an infrared cutoff of 100
 MeV for all particles, a cut on the angular separation from the beam
 axis and a di-particle invariant mass cut which regularizes collinear
 singularities:
 \begin{code}
 cuts = all E >= 100 MeV [prt]
    and all abs (cos(Theta)) <= 0.99 [prt]
    and all M2 >= (1 GeV)^2 [prt, prt]
 \end{code}
 For the graphical analysis, we give a description and labels for the
 $x$- and $y$-axis in \LaTeX\ syntax:
 \begin{code}
 $description = "A WHIZARD Example"
 $x_label = "$\sqrt{s}$/GeV"
 $y_label = "$\sigma(s)$/pb"
 \end{code}
 We define two plots for the lineshape of the \eemm\ process between 88
 and 95 GeV,
 \begin{code}
 $title = "The Z Lineshape in $e^+e^-\to\mu^+\mu^-$"
 plot lineshape_born { x_min = 88 GeV  x_max = 95 GeV }
 \end{code}
 and the same for the radiative process with an additional photon:
 \begin{code}
 $title = "The Z Lineshape in $e^+e^-\to\mu^+\mu^-\gamma$"
 plot lineshape_rc { x_min = 88 GeV  x_max = 95 GeV }
 \end{code}
 %$
 The next part of the \sindarin\ file actually performs the scan:
 \begin{code}
 scan sqrts = ((88.0 GeV => 90.0 GeV /+ 0.5 GeV),
               (90.1 GeV => 91.9 GeV /+ 0.1 GeV),
               (92.0 GeV => 95.0 GeV /+ 0.5 GeV)) {
   beams = e1, E1
   integrate (bornproc) { iterations = 2:1000:"gw", 1:2000 }
   record lineshape_born (sqrts, integral (bornproc) / 1000)
   integrate (rc)   { iterations = 5:3000:"gw", 2:5000 }
   record lineshape_rc (sqrts, integral (rc) / 1000)
 }
 \end{code}
 So from 88 to 90 GeV, we go in 0.5 GeV steps, then from 90 to 92 GeV
 in tenth of GeV, and then up to 95 GeV again in half a GeV steps. The
 partonic beam definition is redundant. Then, the born process is
 integrated, using a certain specification of calls with adaptation of
 grids and weights, as well as a final pass. The lineshape of the Born
 process is defined as a \ttt{record} statement, generating tuples of
 $\sqrt{s}$ and the Born cross section (converted from femtobarn to
 picobarn). The same happens for the radiative $2\to3$ process with a
 bit more iterations because of the complexity, and the definition of
 the corresponding lineshape record.
 
 If you run the \sindarin\ script, you will find an output like:
 \begin{scriptsize}
 \begin{Verbatim}[frame=single]
            | Process library 'default_lib': loading
            | Process library 'default_lib': ... success.
            $description = "A WHIZARD Example"
            $x_label = "$\sqrt{s}$/GeV"
            $y_label = "$\sigma(s)$/pb"
            $title = "The Z Lineshape in $e^+e^-\to\mu^+\mu^-$"
            x_min =  8.800000000000E+01
            x_max =  9.500000000000E+01
            $title = "The Z Lineshape in $e^+e^-\to\mu^+\mu^-\gamma$"
            x_min =  8.800000000000E+01
            x_max =  9.500000000000E+01
            sqrts =  8.800000000000E+01
            | RNG: Initializing TAO random-number generator
            | RNG: Setting seed for random-number generator to 10713
            | Initializing integration for process bornproc:
            | ------------------------------------------------------------------------
            | Process [scattering]: 'bornproc'
            |   Library name  = 'default_lib'
            |   Process index = 1
            |   Process components:
            |     1: 'bornproc_i1':   e-, e+ => mu-, mu+ [omega]
            | ------------------------------------------------------------------------
            | Beam structure: e-, e+
            | Beam data (collision):
            |   e-  (mass = 5.1099700E-04 GeV)
            |   e+  (mass = 5.1099700E-04 GeV)
            |   sqrts = 8.800000000000E+01 GeV
            | Phase space: generating configuration ...
            | Phase space: ... success.
            | Phase space: writing configuration file 'bornproc_i1.phs'
            | Phase space: 1 channels, 2 dimensions
            | Phase space: found 1 channel, collected in 1 grove.
            | Phase space: Using 1 equivalence between channels.
            | Phase space: wood
            | Applying user-defined cuts.
            | OpenMP: Using 8 threads
            | Starting integration for process 'bornproc'
            | Integrate: iterations = 2:1000:"gw", 1:2000
            | Integrator: 1 chains, 1 channels, 2 dimensions
            | Integrator: Using VAMP channel equivalences
            | Integrator: 1000 initial calls, 20 bins, stratified = T
            | Integrator: VAMP
            |=============================================================================|
            | It      Calls  Integral[fb]  Error[fb]   Err[%]    Acc  Eff[%]   Chi2 N[It] |
            |=============================================================================|
               1        800  2.5881432E+05  1.85E+03    0.72    0.20*  48.97
               2        800  2.6368495E+05  9.25E+02    0.35    0.10*  28.32
            |-----------------------------------------------------------------------------|
               2       1600  2.6271122E+05  8.28E+02    0.32    0.13   28.32    5.54   2
            |-----------------------------------------------------------------------------|
               3       1988  2.6313791E+05  5.38E+02    0.20    0.09*  35.09
            |-----------------------------------------------------------------------------|
               3       1988  2.6313791E+05  5.38E+02    0.20    0.09   35.09
            |=============================================================================|
            | Time estimate for generating 10000 events: 0d:00h:00m:05s
            [.......]
 \end{Verbatim}
 \end{scriptsize} %$
 and then the integrations for the other energy points of the scan will
 \begin{figure}
   \centering
   \includegraphics[width=.47\textwidth]{Z-lineshape_1}
   \includegraphics[width=.47\textwidth]{Z-lineshape_2}
 \caption{\label{fig:zlineshape} $Z$ lineshape in the dimuon final
   state (left), and with an additional photon (right)}
 \end{figure}
 follow, and finally the same is done for the radiative process as
 well. At the end of the \sindarin\ script we compile the graphical
 \whizard\ analysis and direct the data for the plots into the file
 \ttt{Z-lineshape.dat}:
 \begin{code}
 compile_analysis { $out_file = "Z-lineshape.dat" }
 \end{code}
 %$
 In this case there is no event generation, but simply the cross
 section values for the scan are dumped into a data file:
 \begin{scriptsize}
 \begin{Verbatim}[frame=single]
            $out_file = "Z-lineshape.dat"
            | Opening file 'Z-lineshape.dat' for output
            | Writing analysis data to file 'Z-lineshape.dat'
            | Closing file 'Z-lineshape.dat' for output
            | Compiling analysis results display in 'Z-lineshape.tex'
 \end{Verbatim}
 \end{scriptsize}
 %$
 Fig.~\ref{fig:zlineshape} shows the graphical \whizard\ output of the
 $Z$ lineshape in the dimuon final state from the scan on the left, and
 the same for the radiative process with an additional photon on the
 right.
 
 %%%%%%%%%%%%%%%
 
 \section{$W$ pairs at LEP II}
 
 This example which can be found as file \ttt{LEP\_cc10.sin} in the
 \ttt{share/examples} directory, shows $W$ pair production in the
 semileptonic mode at LEP II with its final energy of 209 GeV. Because
 there are ten contributing Feynman diagrams, the process has been
 dubbed CC10: charged current process with 10 diagrams. We work within
 the Standard Model:
 \begin{code}
   model = SM
 \end{code}
 Then the process is defined, where no flavor summation is done for the
 jets here:
 \begin{code}
   process cc10 = e1, E1 => e2, N2, u, D
 \end{code}
 A compilation statement is optional, and then we set the muon mass to
 zero:
 \begin{code}
   mmu = 0
 \end{code}
 The final LEP center-of-momentum energy of 209 GeV is set:
 \begin{code}
   sqrts = 209 GeV
 \end{code}
 Then, we integrate the process:
 \begin{code}
   integrate (cc10) { iterations = 12:20000 }
 \end{code}
 Running the \sindarin\ file up to here, results in the output:
 \begin{scriptsize}
 \begin{Verbatim}[frame=single]
           | Process library 'default_lib': loading
           | Process library 'default_lib': ... success.
           SM.mmu =  0.000000000000E+00
           sqrts =  2.090000000000E+02
           | RNG: Initializing TAO random-number generator
           | RNG: Setting seed for random-number generator to 31255
           | Initializing integration for process cc10:
           | ------------------------------------------------------------------------
           | Process [scattering]: 'cc10'
           |   Library name  = 'default_lib'
           |   Process index = 1
           |   Process components:
           |     1: 'cc10_i1':   e-, e+ => mu-, numubar, u, dbar [omega]
           | ------------------------------------------------------------------------
           | Beam structure: [any particles]
           | Beam data (collision):
           |   e-  (mass = 5.1099700E-04 GeV)
           |   e+  (mass = 5.1099700E-04 GeV)
           |   sqrts = 2.090000000000E+02 GeV
           | Phase space: generating configuration ...
           | Phase space: ... success.
           | Phase space: writing configuration file 'cc10_i1.phs'
           | Phase space: 25 channels, 8 dimensions
           | Phase space: found 25 channels, collected in 7 groves.
           | Phase space: Using 25 equivalences between channels.
           | Phase space: wood
           Warning: No cuts have been defined.
           | OpenMP: Using 8 threads
           | Starting integration for process 'cc10'
           | Integrate: iterations = 12:20000
           | Integrator: 7 chains, 25 channels, 8 dimensions
           | Integrator: Using VAMP channel equivalences
           | Integrator: 20000 initial calls, 20 bins, stratified = T
           | Integrator: VAMP
           |=============================================================================|
           | It      Calls  Integral[fb]  Error[fb]   Err[%]    Acc  Eff[%]   Chi2 N[It] |
           |=============================================================================|
              1      19975  6.4714908E+02  2.17E+01    3.36    4.75*   2.33
              2      19975  7.3251876E+02  2.45E+01    3.34    4.72*   2.17
              3      19975  6.7746497E+02  2.39E+01    3.52    4.98    1.77
              4      19975  7.2075198E+02  2.41E+01    3.34    4.72*   1.76
              5      19975  6.5976152E+02  2.26E+01    3.43    4.84    1.46
              6      19975  6.6633310E+02  2.26E+01    3.39    4.79*   1.43
              7      19975  6.7539385E+02  2.29E+01    3.40    4.80    1.43
              8      19975  6.6754027E+02  2.11E+01    3.15    4.46*   1.41
              9      19975  7.3975817E+02  2.52E+01    3.40    4.81    1.53
             10      19975  7.2284275E+02  2.39E+01    3.31    4.68*   1.47
             11      19975  6.5476917E+02  2.18E+01    3.33    4.71    1.33
             12      19975  7.2963866E+02  2.54E+01    3.48    4.92    1.46
           |-----------------------------------------------------------------------------|
             12     239700  6.8779583E+02  6.69E+00    0.97    4.76    1.46    2.18  12
           |=============================================================================|
           | Time estimate for generating 10000 events: 0d:00h:01m:16s
           | Creating integration history display cc10-history.ps and cc10-history.pdf
 \end{Verbatim}
 \end{scriptsize}
 \begin{figure}
   \centering
   \includegraphics[width=.6\textwidth]{cc10_1}
   \\\vspace{5mm}
   \includegraphics[width=.6\textwidth]{cc10_2}
   \caption{Histogram of the dijet invariant mass from the CC10 $W$
     pair production at LEP II, peaking around the $W$ mass (upper
     plot), and of the muon energy (lower plot).}
   \label{fig:cc10}
 \end{figure}
 The next step is event generation. In order to get smooth
 distributions, we set the integrated luminosity to 10
 fb${}^{-1}$. (Note that LEP II in its final year 2000 had an
 integrated luminosity of roughly 0.2 fb${}^{-1}$.)
 \begin{code}
   luminosity = 10
 \end{code}
 With the simulated events corresponding to those 10 inverse femtobarn
 we want to perform a \whizard\ analysis: we are going to plot the
 dijet invariant mass, as well as the energy of the outgoing muon. For
 the plot of the analysis, we define a description and label the $y$
 axis:
 \begin{code}
 $description =
   "A WHIZARD Example.
    Charged current CC10 process from LEP 2."
 $y_label = "$N_{\textrm{events}}$"
 \end{code}
 We also use \LaTeX-syntax for the title of the first plot and the
 $x$-label, and then define the histogram of the dijet invariant mass
 in the range around the $W$ mass from 70 to 90 GeV in steps of half a
 GeV:
 \begin{code}
 $title = "Di-jet invariant mass $M_{jj}$ in $e^+e^- \to \mu^- \bar\nu_\mu u \bar d$"
 $x_label = "$M_{jj}$/GeV"
 histogram m_jets (70 GeV, 90 GeV, 0.5 GeV)
 \end{code}
 And we do the same for the second histogram of the muon energy:
 \begin{code}
 $title = "Muon energy $E_\mu$ in $e^+e^- \to \mu^- \bar\nu_\mu u \bar d$"
 $x_label = "$E_\mu$/GeV"
 histogram e_muon (0 GeV, 209 GeV, 4)
 \end{code}
 Now, we define the \ttt{analysis} consisting of two \ttt{record}
 statements initializing the two observables that are plotted as
 histograms:
 \begin{code}
 analysis = record m_jets (eval M [u,D]);
            record e_muon (eval E [e2])
 \end{code}
 At the very end, we perform the event generation
 \begin{code}
 simulate (cc10)
 \end{code}
 and finally the writing and compilation of the analysis in a named
 data file:
 \begin{code}
 compile_analysis { $out_file = "cc10.dat" }
 \end{code}
 This event generation part screen output looks like this:
 \begin{scriptsize}
 \begin{Verbatim}[frame=single]
           luminosity =  1.000000000000E+01
           $description = "A WHIZARD Example.
              Charged current CC10 process from LEP 2."
           $y_label = "$N_{\textrm{events}}$"
           $title = "Di-jet invariant mass $M_{jj}$ in $e^+e^- \to \mu^- \bar\nu_\mu u \bar d$"
           $x_label = "$M_{jj}$/GeV"
           $title = "Muon energy $E_\mu$ in $e^+e^- \to \mu^- \bar\nu_\mu u \bar d$"
           $x_label = "$E_\mu$/GeV"
           | Starting simulation for process 'cc10'
           | Simulate: using integration grids from file 'cc10_m1.vg'
           | RNG: Initializing TAO random-number generator
           | RNG: Setting seed for random-number generator to 9910
           | OpenMP: Using 8 threads
           | Simulation: using n_events as computed from luminosity value
           | Events: writing to raw file 'cc10.evx'
           | Events: generating 6830 unweighted, unpolarized events ...
           | Events: event normalization mode '1'
           |         ... event sample complete.
           Warning: Encountered events with excess weight: 39 events (  0.571 %)
           | Maximum excess weight = 1.027E+00
           | Average excess weight = 6.764E-04
           | Events: closing raw file 'cc10.evx'
           $out_file = "cc10.dat"
           | Opening file 'cc10.dat' for output
           | Writing analysis data to file 'cc10.dat'
           | Closing file 'cc10.dat' for output
           | Compiling analysis results display in 'cc10.tex'
 \end{Verbatim}
 \end{scriptsize} %$
 Then comes the \LaTeX\ output of the compilation of the graphical
 analysis. Fig.~\ref{fig:cc10} shows the two histograms as the are
 produced as result of the \whizard\ internal graphical analysis.
 
 %%%%%%%%%%%%%%%
 
 \section{Higgs search at LEP II}
 
 This example can be found under the name \ttt{LEP\_higgs.sin} in the
 \ttt{share/doc} folder of \whizard. It displays different search
 channels for a very light would-be SM Higgs boson of mass 115 GeV at
 the LEP II machine at its highest energy it finally achieved, 209 GeV.
 First, we use the Standard Model:
 \begin{code}
 model = SM
 \end{code}
 Then, we define aliases for neutrinos, antineutrinos, light quarks and
 light anti-quarks:
 \begin{code}
 alias n = n1:n2:n3
 alias N = N1:N2:N3
 alias q = u:d:s:c
 alias Q = U:D:S:C
 \end{code}
 Now, we define the signal process, which is Higgsstrahlung,
 \begin{code}
 process zh = e1, E1 => Z, h
 \end{code}
 the missing-energy channel,
 \begin{code}
 process nnbb = e1, E1 => n, N, b, B
 \end{code}
 and finally the 4-jet as well as dilepton-dijet channels:
 \begin{code}
 process qqbb = e1, E1 => q, Q, b, B
 process bbbb = e1, E1 => b, B, b, B
 process eebb = e1, E1 => e1, E1, b, B
 process qqtt = e1, E1 => q, Q, e3, E3
 process bbtt = e1, E1 => b, B, e3, E3
 
 compile
 \end{code}
 and we compile the code. We set the center-of-momentum energy to the
 highest energy LEP II achieved,
 \begin{code}
 sqrts = 209 GeV
 \end{code}
 For the Higgs boson, we take the values of a would-be SM Higgs boson
 with mass of 115 GeV, which would have had a width of a bit more than
 3 MeV:
 \begin{code}
 mH = 115 GeV
 wH = 3.228 MeV
 \end{code}
 We take a running $b$ quark mass to take into account NLO corrections
 to the $Hb\bar b$ vertex, while all other fermions are massless:
 \begin{code}
 mb = 2.9 GeV
 me = 0
 ms = 0
 mc = 0
 \end{code}
 \begin{scriptsize}
 \begin{Verbatim}[frame=single]
            | Process library 'default_lib': loading
            | Process library 'default_lib': ... success.
            sqrts =  2.090000000000E+02
            SM.mH =  1.150000000000E+02
            SM.wH =  3.228000000000E-03
            SM.mb =  2.900000000000E+00
            SM.me =  0.000000000000E+00
            SM.ms =  0.000000000000E+00
            SM.mc =  0.000000000000E+00
 \end{Verbatim}
 \end{scriptsize}
 To avoid soft-collinear singular phase-space regions, we apply an
 invariant mass cut on light quark pairs:
 \begin{code}
 cuts = all M >= 10 GeV [q,Q]
 \end{code}
 Now, we integrate the signal process as well as the combined signal
 and background processes:
 \begin{code}
 integrate (zh) { iterations = 5:5000}
 
 integrate(nnbb,qqbb,bbbb,eebb,qqtt,bbtt) { iterations = 12:20000 }
 \end{code}
 \begin{scriptsize}
 \begin{Verbatim}[frame=single]
            | RNG: Initializing TAO random-number generator
            | RNG: Setting seed for random-number generator to 21791
            | Initializing integration for process zh:
            | ------------------------------------------------------------------------
            | Process [scattering]: 'zh'
            |   Library name  = 'default_lib'
            |   Process index = 1
            |   Process components:
            |     1: 'zh_i1':   e-, e+ => Z, H [omega]
            | ------------------------------------------------------------------------
            | Beam structure: [any particles]
            | Beam data (collision):
            |   e-  (mass = 0.0000000E+00 GeV)
            |   e+  (mass = 0.0000000E+00 GeV)
            |   sqrts = 2.090000000000E+02 GeV
            | Phase space: generating configuration ...
            | Phase space: ... success.
            | Phase space: writing configuration file 'zh_i1.phs'
            | Phase space: 1 channels, 2 dimensions
            | Phase space: found 1 channel, collected in 1 grove.
            | Phase space: Using 1 equivalence between channels.
            | Phase space: wood
            | Applying user-defined cuts.
            | OpenMP: Using 8 threads
            | Starting integration for process 'zh'
            | Integrate: iterations = 5:5000
            | Integrator: 1 chains, 1 channels, 2 dimensions
            | Integrator: Using VAMP channel equivalences
            | Integrator: 5000 initial calls, 20 bins, stratified = T
            | Integrator: VAMP
            |=============================================================================|
            | It      Calls  Integral[fb]  Error[fb]   Err[%]    Acc  Eff[%]   Chi2 N[It] |
            |=============================================================================|
               1       4608  1.6114109E+02  5.52E-04    0.00    0.00*  99.43
               2       4608  1.6114220E+02  5.59E-04    0.00    0.00   99.43
               3       4608  1.6114103E+02  5.77E-04    0.00    0.00   99.43
               4       4608  1.6114111E+02  5.74E-04    0.00    0.00*  99.43
               5       4608  1.6114103E+02  5.66E-04    0.00    0.00*  99.43
            |-----------------------------------------------------------------------------|
               5      23040  1.6114130E+02  2.53E-04    0.00    0.00   99.43    0.82   5
            |=============================================================================|
            [.....]
 \end{Verbatim}
 \end{scriptsize}
 \begin{figure}
   \centering
   \includegraphics[width=.48\textwidth]{lep_higgs_1}
   \includegraphics[width=.48\textwidth]{lep_higgs_2}
   \\\vspace{5mm}
   \includegraphics[width=.48\textwidth]{lep_higgs_3}
   \caption{Upper line: final state $bb + E_{miss}$, histogram of
     the invisible mass distribution (left), and of the di-$b$
     distribution (right). Lower plot: light dijet distribution in the
     $bbjj$ final state.}
   \label{fig:lep_higgs}
 \end{figure}
 Because the other integrations look rather similar, we refrain from
 displaying them here, too. As a next step, we define titles,
 descriptions and axis labels for the histograms we want to
 generate. There are two of them, one os the invisible mass
 distribution, the other is the di-$b$-jet invariant mass. Both
 histograms are taking values between 70 and 130 GeV with
 bin widths of half a GeV:
 \begin{code}
 $description =
   "A WHIZARD Example. Light Higgs search at LEP. A 115 GeV pseudo-Higgs
     has been added. Luminosity enlarged by two orders of magnitude."
 $y_label = "$N_{\textrm{events}}$"
 
 $title = "Invisible mass distribution in $e^+e^- \to \nu\bar\nu b \bar b$"
 $x_label = "$M_{\nu\nu}$/GeV"
 histogram m_invisible (70 GeV, 130 GeV, 0.5 GeV)
 
 $title = "$bb$ invariant mass distribution in $e^+e^- \to \nu\bar\nu b \bar b$"
 $x_label = "$M_{b\bar b}$/GeV"
 histogram m_bb (70 GeV, 130 GeV, 0.5 GeV)
 \end{code}
 The analysis is initialized by defining the two records for the
 invisible mass and the invariant mass of the two $b$ jets:
 \begin{code}
 analysis = record m_invisible (eval M [n,N]);
            record m_bb (eval M [b,B])
 \end{code}
 In order to have enough statistics, we enlarge the LEP integrated
 luminosity at 209 GeV by more than two orders of magnitude:
 \begin{code}
 luminosity = 10
 \end{code}
 We start event generation by simulating the process with two $b$ jets
 and two neutrinos in the final state:
 \begin{code}
 simulate (nnbb)
 \end{code}
 As a third histogram, we define the dijet invariant mass of two light
 jets:
 \begin{code}
 $title = "Dijet invariant mass distribution in $e^+e^- \to q \bar q b \bar b$"
 $x_label = "$M_{q\bar q}$/GeV"
 histogram m_jj (70 GeV, 130 GeV, 0.5 GeV)
 \end{code}
 Then we simulate the 4-jet process defining the light-dijet
 distribution as a local record:
 \begin{code}
 simulate (qqbb) { analysis = record m_jj (eval M / 1 GeV [combine [q,Q]]) }
 \end{code}
 Finally, we compile the analysis,
 \begin{code}
 compile_analysis { $out_file = "lep_higgs.dat" }
 \end{code}
 \begin{scriptsize}
 \begin{Verbatim}[frame=single]
            | Starting simulation for process 'nnbb'
            | Simulate: using integration grids from file 'nnbb_m1.vg'
            | RNG: Initializing TAO random-number generator
            | RNG: Setting seed for random-number generator to 21798
            | OpenMP: Using 8 threads
            | Simulation: using n_events as computed from luminosity value
            | Events: writing to raw file 'nnbb.evx'
            | Events: generating 1070 unweighted, unpolarized events ...
            | Events: event normalization mode '1'
            |         ... event sample complete.
            Warning: Encountered events with excess weight: 207 events ( 19.346 %)
            | Maximum excess weight = 1.534E+00
            | Average excess weight = 4.909E-02
            | Events: closing raw file 'nnbb.evx'
            $title = "Dijet invariant mass distribution in $e^+e^- \to q \bar q b \bar b$"
            $x_label = "$M_{q\bar q}$/GeV"
            | Starting simulation for process 'qqbb'
            | Simulate: using integration grids from file 'qqbb_m1.vg'
            | RNG: Initializing TAO random-number generator
            | RNG: Setting seed for random-number generator to 21799
            | OpenMP: Using 8 threads
            | Simulation: using n_events as computed from luminosity value
            | Events: writing to raw file 'qqbb.evx'
            | Events: generating 4607 unweighted, unpolarized events ...
            | Events: event normalization mode '1'
            |         ... event sample complete.
            Warning: Encountered events with excess weight: 112 events (  2.431 %)
            | Maximum excess weight = 8.875E-01
            | Average excess weight = 4.030E-03
            | Events: closing raw file 'qqbb.evx'
            $out_file = "lep_higgs.dat"
            | Opening file 'lep_higgs.dat' for output
            | Writing analysis data to file 'lep_higgs.dat'
            | Closing file 'lep_higgs.dat' for output
            | Compiling analysis results display in 'lep_higgs.tex'
 \end{Verbatim}
 \end{scriptsize}
 The graphical analysis of the events generated by \whizard\ are shown
 in Fig.~\ref{fig:lep_higgs}. In the upper left, the invisible mass
 distribution in the $b\bar b + E_{miss}$ state is shown, peaking
 around the $Z$ mass. The upper right shows the $M(b\bar b)$
 distribution in the same final state, while the lower plot has the
 invariant mass distribution of the two non-$b$-tagged (light) jets in
 the $bbjj$ final state. The latter shows only the $Z$
 peak, while the former exhibits the narrow would-be 115 GeV Higgs
 state.
 
 %%%%%%%%%%%%%%%
 
 \section{Deep Inelastic Scattering at HERA}
 
 %%%%%%%%%%%%%%%
 
 \section{$W$ endpoint at LHC}
 
 %%%%%%%%%%%%%%%
 
 \section{SUSY Cascades at LHC}
 
 %%%%%%%%%%%%%%%
 
 \section{Polarized $WW$ at ILC}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{Technical details -- Advanced Spells}
 \label{chap:tuning}
 
 \section{Efficiency and tuning}
 
 Since massless fermions and vector bosons (or almost massless states
 in a certain approximation) lead to restrictive selection rules for
 allowed helicity combinations in the initial and final state. To make
 use of this fact for the efficiency of the \whizard\ program, we are
 applying some sort of heuristics: \whizard\ dices events into all
 combinatorially possible helicity configuration during a warm-up
 phase. The user can specify a helicity threshold which sets the number
 of zeros \whizard\ should have got back from a specific helicity
 combination in order to ignore that combination from now on. By that
 mechanism, typically half up to more than three quarters of all
 helicity combinations are discarded (and hence the corresponding
 number of matrix element calls). This reduces calculation time up to
 more than one order of magnitude. \whizard\ shows at the end of the
 integration those helicity combinations which finally contributed to
 the process matrix element.
 
 Note that this list -- due to the numerical heuristics -- might very
 well depend on the number of calls for the matrix elements per
 iteration, and also on the corresponding random number seed.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{New External Physics Models}
 \label{chap:extmodels}
 
 It is never possible to include all incarnations of physics models that
 can be described by the maybe weirdest form of a quantum field theory
 in a tailor-made implementation within a program like \whizard. Users
 clearly want to be able to use their own special type of model; in
 order to do so there are external tools to translate models described
 by their field content and Lagrangian densities into Feynman rules and
 make them available in an event generator like \whizard. In this
 chapter, we describe the interfaces to two such external models,
 \sarah\ and \FeynRules.
 
 The \FeynRules\ interface had been started already for the legacy
 version \whizard\ttt{1} (where it had to be downloaded from
 \url{https://whizard.hepforge.org} as a separate package), but
 for the \whizard\ttt{two} release series it has been included in the
 \FeynRules\ package (from their version v1.6.0 on). Note that there
 was a regression for the usage of external models (from either \sarah\
 or \FeynRules) in the first release of series v2.2, v2.2.0. This has
 been fixed in all upcoming versions.
 
 Besides using \sarah\ or \FeynRules\ via their interfaces, there is
 now a much easier way to let those programs output model files in the
 "Universal FeynRules Output" (or \UFO). This option does not have any
 principle limitations for models, and also does not rely on the never
 truly constant interfaces between two different tools. Their usage is
 described in Sec.~\ref{sec:ufo}.
 
 %%%%%%%%%%%%%%%
 
 \section{New physics models via \sarah}
 \sarah~\cite{Staub:2008uz,Staub:2009bi,Staub:2010jh,Staub:2012pb,Staub:2013tta}
 is a \Mathematica~\cite{mathematica} package which
 derives for a given model the
 minimum conditions of the vacuum, the mass matrices, and vertices at tree-level
 as well as expressions for the one-loop corrections for all masses and the
 full two-loop renormalization group equations (RGEs). The vertices can be exported
 to be used with \whizard/\oMega. All other information can be used to generate
 \fortran\ source code for the RGE solution tool and spectrum generator
 \spheno~\cite{Porod:2003um,Porod:2011nf}  to get a spectrum generator
 for any model. The
 advantage is that \spheno\ calculates a consistent set of parameters (couplings,
 masses, rotation matrices, decay widths) which can be used as input for \whizard.
 \sarah\ and \spheno\ can be also downloaded from the \ttt{HepForge} server:
 \begin{center}
 \url{https://sarah.hepforge.org} \\
 \url{https://spheno.hepforge.org}
 \end{center}
 
 
 \subsection{\whizard/\oMega\ model files from \sarah}
 
 \subsubsection{Generating the model files}
 
 Here we are giving only the information relevant to generate models
 for \whizard. For more details about the installation of \sarah\ and
 an exhaustion documentation about its usage, confer the \sarah\
 manual.
 
 To generate the model files for \whizard/\oMega\ with \sarah, a
 new \Mathematica\ session has to be started. \sarah\ is loaded via
 \begin{code}
 <<SARAH-4.2.1/SARAH.m;
 \end{code}
 if \sarah\ has been stored in the applications directory of
 \Mathematica. Otherwise, the full path has to be given
 \begin{code}
 <<[Path_to_SARAH]/SARAH.m;
 \end{code}
 To get an overview which models are delivered with \sarah, the command \verb"ShowModels"
 can be used. As an example, we use in the following the triplet
 extended MSSM (TMSSM) and initialize it in \sarah\ via
 \begin{code}
 Start["TMSSM"];
 \end{code}
 Finally, the output intended for \whizard/\oMega\ is started via
 \begin{code}
 MakeWHIZARD[Options]
 \end{code}
 The possible options of the \verb"MakeWHIZARD" command are
 \begin{enumerate}
   \item \verb"WriteOmega", with values: \verb"True" or \verb"False", default:
     \verb"True" \\
     Defines if the model files for \oMega\ should be written
   \item \verb"WriteWHIZARD", with values: \verb"True" or \verb"False",
     default: \verb"True" \\
     Defines if the model files for \whizard\ should be written
   \item \verb"Exclude", with values: list of generic type, Default:
     \verb"{SSSS}" \\
     Defines which generic vertices are {\em not} exported to the model
     file
   \item \verb"WOModelName", with values: string, default: name of the
     model in \sarah\ followed by \verb"_sarah"  \\
     Gives the possibility to change the model name
   \item \verb"MaximalCouplingsPerFile", with values: integer, default:
     \ttt{150} \\
     Defines the maximal number of couplings written per file
   \item \verb"Version", with values: formatted number, Default:
     \verb"2.2.1"~\footnote{Due to a regression in \whizard\ version
       v2.2.0, \sarah\ models cannot be successfully linked within
       that version. Hence, the default value here has been set to
       version number 2.2.1}, \\
     Defines the version of \whizard\ for which the model file is generated
 \end{enumerate}
 All options and the default values are also shown in the
 \Mathematica\ session via \newline\verb"Options[MakeWHIZARD]".
 
 \subsubsection{Using the generated model files with \whizard}
 
 After the interface has completed evaluation, the generated files can
 be found in the subdirectory \verb"WHIZARD_Omega" of {\sarah}s output
 directory. In order to use it the generated code must be compiled and
 installed. For this purpose, open a terminal, enter the output directory
 \begin{code}
 <PATH_to_SARAH>/Output/TMSSM/EWSB/WHIZARD_Omega/
 \end{code}
 and run
 %
 \begin{code}
 ./configure
 make install
 \end{code}
 %
 By default, the last command installs the compiled model into \verb".whizard"
 in current user's home directory where it is automatically picked up by
 \whizard. Alternative installation paths can be specified using the
 \verb"--prefix" option to \whizard.
 %
 \begin{code}
 ./configure --prefix=/path/to/installation/prefix
 \end{code}
 %
 If the files are installed into the \whizard\
 installation prefix, the program will also pick them up automatically, while
 {\whizard}'s \verb"--localprefix" option must be used to communicate any other
 choice to \whizard. In case \whizard\ is not available in the binary search
 path, the \verb"WO_CONFIG" environment variable can be used to point
 \verb"configure" to the binaries
 %
 \begin{code}
 ./configure WO_CONFIG=/path/to/whizard/binaries
 \end{code}
 %
 More information on the available options and their syntax can be obtained with
 the
 \verb"--help" option.
 
 After the model is compiled it can be used in \whizard\ as
 \begin{code}
 model = tmssm_sarah
 \end{code}
 
 
 
 \subsection{Linking \spheno\ and \whizard}
 As mentioned above, the user can also use \spheno\ to generate spectra
 for its models. This is done by means of \fortran\ code for \spheno,
 exported from \sarah.  To do so, the user has to apply the command
 \verb"MakeSPheno[]". For more details
 about the options of this command and how to compile and use the \spheno\ output,
 we refer to the \sarah\ manual. \\
 As soon as the \spheno\ version for the given model is ready it can be used to
 generate files with all necessary numerical values for the parameters in a format
 which is understood by \whizard. For this purpose, the corresponding flag in the
 Les Houches input file of \spheno\ has to be turned on:
 \begin{code}
 Block SPhenoInput   # SPheno specific input
 ...
 75 1               # Write WHIZARD files
 \end{code}
 Afterwards, \spheno\ returns not only the spectrum file in the
 standard SUSY Les Houches accord (SLHA) format (for more details about
 the SLHA and the \whizard\ SLHA interface cf. Sec.~\ref{sec:slha}),
 but also an additional file called \verb"WHIZARD.par.TMSSM" for our example.
 This file can be used
 in the \sindarin\ input file via
 \begin{code}
 include ("WHIZARD.par.TMSSM")
 \end{code}
 
 %%%%%
 
 \subsection{BSM Toolbox}
 
 A convenient way to install \sarah\ together with \whizard, \spheno\
 and some  other codes are the \ttt{BSM Toolbox} scripts
 \footnote{Those script have been published
 under the name SUSY Toolbox but \sarah\ is with version 4 no longer
 restricted to SUSY models}~\cite{Staub:2011dp}. These scripts are
 available at
 \begin{center}
  \url{https://sarah.hepforge.org/Toolbox.html}
 \end{center}
 The \ttt{Toolbox} provides two scripts. First, the \verb"configure" script is
 used via
 \begin{code}
 toolbox-src-dir> mkdir build
 toolbox-src-dir> cd build
 toolbox-src-dir> ../configure
 \end{code}
 %
 The  \verb"configure" script checks for the requirements of the
 different packages and downloads all codes. All downloaded archives will
 be placed in the \verb"tarballs" subdirectory of the directory containing the
 \verb"configure" script.
 Command line options can be used to disable specific packages and to point the
 script to custom locations of compilers and of the \Mathematica\ kernel; a full
 list of those can be obtained by calling \verb"configure" with the \verb"--help"
 option.
 
 After \verb"configure" finishes successfully, \verb"make" can be called to build
 all configured packages
 %
 \begin{code}
 toolbox-build-dir> make
 \end{code}
 
 \verb"configure" creates also the second script which automates the implementation
 of a new model into all packages. The \verb"butler" script takes as argument the
 name of the model in \sarah, e.g.
 \begin{code}
 > ./butler TMSSM
 \end{code}
 The \verb"butler" script runs \sarah\ to get the output in the same
 form as the \whizard/\oMega\
 model files and the code for \spheno. Afterwards, it installs the
 model in all packages and compiles the new \whizard/\oMega\ model
 files as well as the new \spheno\ module.
 
 %%%%%
 \newpage
 
 \section{New physics models via \FeynRules}
 
 In this section, we present the interface between the external tool
 \FeynRules\ \cite{Christensen:2008py,Christensen:2009jx,Duhr:2011se}
 and \whizard. \FeynRules\ is a
 \Mathematica~\cite{mathematica} package that allows to derive
 Feynman rules from any perturbative quantum field theory-based Lagrangian
 in an automated way. It can be downloaded from
 \begin{center}
   \url{http://feynrules.irmp.ucl.ac.be/}
 \end{center}
 The input provided by the user is threefold and consists
 of the Lagrangian defining the model, together with the definitions of
 all the
 particles and parameters that appear in the model.
 Once this information is provided, \FeynRules\ can perform basic checks
 on the sanity of the implementation (e.g. hermiticity, normalization
 of the quadratic terms), and finally computes all the interaction
 vertices associated  with the model and store them in an internal
 format for later processing. After the Feynman rules have been
 obtained, \FeynRules\ can export the interaction vertices to \whizard\
 via a dedicated interface~\cite{Christensen:2010wz}. The interface
 checks whether all the vertices are compliant with the structures
 supported by \whizard's
 matrix element generator \oMega, and discard them in the case
 they are not supported. The output of the interface consists of a set
 of files organized in a single directory which can be injected into
 \whizard/\oMega\ and used as any other built-in models. Together with
 the model files, a framework is created which allows to communicate
 the new models to \whizard\ in a well defined way, after which
 step the model can be used exactly like the built-in ones.
 This specifically means that the user is not required to
 manually modify the code of \whizard/\oMega, the models created by the
 interface can be used directly without any further user intervention.
 We first describe the installation and general usage of the interface,
 and then list the general properties like the supported particle
 types, color quantum numbers and Lorentz structures as well as types
 of gauge interactions.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \subsection{Installation and Usage of the \whizard-\FeynRules\ interface}
 \label{sec:interface-usage}
 
 \paragraph{{\bf Installation and basic usage:}}
 %
 From \FeynRules\ version 1.6.0 onward, the interface to \whizard\ is
 part of the \FeynRules\ distribution\footnote{Note that though the
   main interface of \FeynRules\ to \whizard\ is for the most recent
   \whizard\ release, but also the legacy branch
   \whizard\ttt{1} is supported.}. In addition, the latest version
 of the interface can be downloaded from the \whizard\ homepage on
 \ttt{HepForge}. There you can also find an installer that can be used
 to inject the interface into an existing \FeynRules\
 installation (which allows to use the interface with the \FeynRules\
 release series1.4.x where it is not part of the package).
 
 Once installed, the interface can be called and used in the same way
 \FeynRules' other interfaces described
 in~\cite{Christensen:2008py}. The details of how to install and use
 \FeynRules\ itself can be found
 there,~\cite{Christensen:2008py,Christensen:2009jx,Duhr:2011se}. Here,
 we only describe how to use the interface to inject new models into
 \whizard.  For example, once the  \FeynRules\ environment has been
 initialized and a model has been loaded, the command
 \begin{code}
   WriteWOOutput[L]
 \end{code}
 will call the \ttt{FeynmanRules} command to extract the Feynman
 rules from the Lagrangian \ttt{L}, translate them together with the
 model data and finally write the files necessary for using the model
 within \whizard\ to an output directory (the name of which is inferred
 from the model name by default). Options can be added for further
 control over the translation process (see
 Sec.~\ref{app:interface-options}). Instead of using a Lagrangian, it
 is also possible to call the interface on a pure vertex list. For
 example, the following command
 \begin{code}
   WriteWOOutput[Input -> list]
 \end{code}
 will directly translate the vertex list \ttt{list}. Note that this
 vertex list must be given in flavor-expanded form in order for the
 interface to process it correctly.
 
 The interface also supports the \ttt{WriteWOExtParams} command
 described in~\cite{Christensen:2008py}. Issuing
 \begin{code}
   WriteWOExtParams[filename]
 \end{code}
 will write a list of all the external parameters to
 \ttt{filename}. This is done in the form of a \sindarin\
 script. The only option accepted by the command above is the target
 version of \whizard, set by the option \ttt{WOWhizardVersion}.
 
 During execution, the interface will print out a series of
 messages. It is highly advised to carefully read through this output
 as it not only summarizes the settings and the location of the output
 files, but also contains information on any skipped vertices or
 potential incompatibilities of the model with \whizard.
 
 After the interface has run successfully and written the model files to the
 output directory, the model must be imported into \whizard. For doing
 so, the model files have to be compiled and can then be installed
 independently of \whizard. In the simplest scenario, assuming that the
 output directory is the current working directory and that the
 \whizard\ binaries can be found in the current \ttt{\$\{PATH\}},
 the installation is performed by simply executing
 \begin{code}
 ./configure~\&\&~make clean~\&\&~make install
 \end{code}
 
 This will compile the model and install it into the directory
 \ttt{\$\{HOME\}/.whizard}, making it fully available to \whizard\
 without any further intervention. The build system can be adapted to
 more complicated cases through several options to the
 \ttt{configure} which are listed in the \ttt{INSTALL} file
 created in the output directory. A detailed explanation of all options
 can be found in Sec.~\ref{app:interface-options}.
 
 \paragraph{\bf Supported fields and vertices:}
 
 The following fields are currently supported by the interface:
 scalars, Dirac and Majorana fermions, vectors and symmetric tensors.
 The set of accepted operators, the full list of which can be found in
 Tab.~\ref{tab-operators}, is a subset of all the operators supported
 by \oMega. While still limited, this list is sufficient for a large
 number of BSM models. In addition, a future version of
 \whizard/\oMega\ will support the definition of completely general
 Lorentz structures in the model, allowing the interface to
 translate all interactions handled by \FeynRules. This will be done by
 means of a parser within \oMega\ of the \ttt{UFO} file format for
 model files from \FeynRules.
 
 \begin{table*}[!t]
 \centerline{\begin{tabular}{|c|c|}
 \hline Particle spins & Supported Lorentz structures \\\hline\hline
 FFS & \parbox{0.7\textwidth}{\raggedright
    All operators of dimension four are supported.
 \strut}\\\hline
 FFV & \parbox[t]{0.7\textwidth}{\raggedright
    All operators of dimension four are
    supported.
 \strut}\\\hline
 SSS & \parbox{0.7\textwidth}{\raggedright
    All dimension three interactions are supported.
 \strut}\\\hline
 SVV & \parbox[t]{0.7\textwidth}{\raggedright
    Supported operators:\\
    \mbox{}\hspace{5ex}$\begin{aligned}
       \text{dimension 3:} & \quad\mathcal{O}_3 = V_1^\mu V_{2\mu}\phi \mbox{}\\
       \text{dimension 5:} & \quad\mathcal{O}_5 = \phi
          \left(\partial^\mu V_1^\nu - \partial^\nu V_1^\mu\right)
          \left(\partial_\mu V_{2\nu} - \partial_\nu V_{2\mu}\right)
    \end{aligned}$\\
 Note that $\mathcal{O}_5$ generates the effective gluon-gluon-Higgs couplings obtained by integrating out heavy quarks.
 \strut}\\\hline
 SSV & \parbox[t]{0.7\textwidth}{\raggedright
    $\left(\phi_1\partial^\mu\phi_2 - \phi_2\partial^\mu\phi_1\right)V_\mu\;$
    type interactions are supported.
 \strut}\\\hline
 SSVV & \parbox{0.7\textwidth}{\raggedright
    All dimension four interactions are supported.
 \strut}\\\hline
 SSSS & \parbox{0.7\textwidth}{\raggedright
    All dimension four interactions are supported.
 \strut}\\\hline
 VVV & \parbox[t]{0.7\textwidth}{\raggedright
    All parity-conserving dimension four operators are supported, with
    the restriction that non-gauge interactions may be split into
    several vertices and can only be handled if all three fields are
    mutually different.\strut
 \strut}\\\hline
 VVVV & \parbox[t]{0.7\textwidth}{\raggedright
    All parity conserving dimension four operators are supported.
 \strut}\\\hline
 TSS, TVV, TFF & \parbox[t]{0.7\textwidth}{\raggedright
    The three point couplings in the Appendix of Ref.\
    \cite{Han:1998sg} are supported.
 \strut}\\\hline
 \end{tabular}}
 \caption{All Lorentz structures currently supported by the
   \whizard-\FeynRules\ interface, sorted with respect to the spins of
   the particles. ``S'' stands for scalar, ``F'' for fermion (either
   Majorana or Dirac) and ``V'' for vector.}
 \label{tab-operators}
 \end{table*}
 
 \paragraph{\bf Color:}
 %
 Color is treated in \oMega\ in the color flow decomposition,
 with the flow structure being implicitly determined from
 the representations of the particles present at the vertex. Therefore, the
 interface has to strip the color structure from the vertices derived by
 \FeynRules\ before writing them out to the model files.
 While this process is straightforward for all color structures which
 correspond only to a single flow assignment, vertices with several
 possible flow configurations must be treated with care in order to
 avoid mismatches between the flows assigned by \oMega\ and those
 actually encoded in the couplings. To this end, the interface derives
 the color flow decomposition from the color structure determined by
 \FeynRules\ and rejects all vertices which would lead to a wrong flow
 assignment by \oMega\ (these rejections are accompanied by warnings
 from the interface)\footnote{For the old \whizard\ttt{1} legacy
   branch, there was a maximum number of external color flows that had
   to explicitly specified. Essentially, this is $n_8 - \frac{1}{2}n_3$
   where $n_8$ is the maximum number of external color octets and $n_3$
   is the maximum number of external triplets and antitriplets. This
   can be set in the \whizard/\FeynRules\ interface by the
   \ttt{WOMaxNcf} command, whose default is \ttt{4}.}.
 
 At the moment, the $SU(3)_C$ representations supported by
 both \whizard\ and the interface are singlets ($1$), triplets ($3$),
 antitriplets ($\bar{3}$) and octets ($8$). Tab.~\ref{tab:su3struct}
 shows all combinations of these representations which can
 form singlets together with the support status of the respective color
 structures in \whizard\ and the interface. Although the supported
 color structures do not comprise all possible singlets, the list is
 sufficient for a large number of SM extensions. Furthermore, a future
 revision of \whizard/\oMega\ will allow for explicit color flow
 assignments, thus removing most of the current restrictions.
 
 \begin{table*}
 \centerline{\begin{tabular}{|c|c|}
 \hline $SU(3)_C$ representations &
    Support status
 \\\hline\hline
 \parbox[t]{0.2\textwidth}{
    \centerline{\begin{tabular}[t]{lll}
    $111,\quad$ & $\bar{3}31,\quad$ & $\bar{3}38,$ \\
    $1111,$ & $\bar{3}311,$ & $\bar{3}381$
    \end{tabular}}} &
 \parbox[t]{0.7\textwidth}{\raggedright\strut Fully supported by the interface\strut}
 \\\hline
 $888,\quad 8881$ &
 \parbox{0.7\textwidth}{\raggedright\strut Supported only if at least two of the octets
 are identical particles.\strut}
 \\\hline
 $881,\quad 8811$ &
 \parbox{0.7\textwidth}{\raggedright\strut Fully supported by the
   interface\footnote{%
     Not available in version 1.95 and earlier. Note that in order to
     use such couplings in 1.96/97, the
     \oMega\ option \ttt{2g} must be added to the process definition
     in \ttt{whizard.prc}.}.\strut}
 \\\hline
 $\bar{3}388$ &
 \parbox{0.7\textwidth}{\raggedright\strut Supported only if the octets
   are identical
 particles.\strut}
 \\\hline
 $8888$ &
 \parbox{0.7\textwidth}{\raggedright\strut The only supported flow structure is
 \begin{equation*}
 \parbox{21mm}{\includegraphics{flow4}}\cdot\;\Gamma(1,2,3,4)
    \quad+\quad \text{all acyclic permutations}
 \end{equation*}
 where $\Gamma(1,2,3,4)$ represents the Lorentz structure associated with the
 first flow.\strut}
 \\\hline
 \parbox[t]{0.2\textwidth}{
    \centerline{\begin{tabular}[t]{lll}
    $333,\quad$ & $\bar{3}\bar{3}\bar{3},\quad$ & $3331$\\
    $\bar{3}\bar{3}\bar{3}1,$ & $\bar{3}\bar{3}33$
    \end{tabular}}} &
 \parbox[t]{0.7\textwidth}{\raggedright\strut Unsupported (at the
   moment)\strut}
 \\\hline
 \end{tabular}}
 \caption{All possible combinations of three or four $SU(3)_C$
 representations supported by \FeynRules\ which can be used to build singlets,
 together with the support status of the corresponding color structures in
 \whizard\ and the interface.}
 \label{tab:su3struct}
 \end{table*}
 
 \paragraph{\bf Running $\alpha_S$:}
 
 While a running strong coupling is fully supported by the interface, a
 choice has to be made which quantities are to be reevaluated when the
 strong coupling is evolved. By default \ttt{aS}, \ttt{G} (see
 Ref.~\cite{Christensen:2008py} for the nomenclature regarding
 the QCD coupling) and any vertex factors depending on them are evolved.
 The list of internal parameters that are to be recalculated (together
 with the vertex factors depending on them) can be
 extended (beyond \ttt{aS} and \ttt{G}) by using
 the option \ttt{WORunParameters} when calling the
 interface~\footnote{As the legacy branch, \whizard\ttt{1}, does not
   support a running strong coupling, this is also vetoed by the
   interface when using \whizard \ttt{1.x}.}.
 
 \paragraph{\bf Gauge choices:}
 \label{sec:gauge-choices}
 
 The interface supports the unitarity, Feynman and $R_\xi$ gauges. The choice of
 gauge must be communicated to the interface via the option \ttt{WOGauge}.
 Note that massless gauge bosons are always treated in Feynman gauge.
 
 If the selected gauge is Feynman or $R_\xi$, the interface can
 automatically assign the proper masses to the Goldstone bosons. This behavior is
 requested by using the \ttt{WOAutoGauge} option. In the $R_\xi$
 gauges, the symbol representing the gauge $\xi$ must be communicated to the
 interface by using the \ttt{WOGaugeSymbol} option (the symbol is
 automatically introduced into the list of external
 parameters if \ttt{WOAutoGauge} is
 selected at the same time). This feature can be used to automatically extend
 models implemented in Feynman gauge to the $R_\xi$ gauges.
 
 Since \whizard\ (at least until the release series 2.3) is a
 tree-level tool working with helicity amplitudes, the ghost sector is
 irrelevant for \whizard\ and hence dropped by the interface.
 
 \subsection{Options of the \whizard-\FeynRules\ interface}
 \label{app:interface-options}
 
 In the following we present a comprehensive list of all the options accepted by
 \ttt{WriteWOOutput}. Additionally, we note that all options of the
 \FeynRules\ command \ttt{FeynmanRules} are accepted by
 \ttt{WriteWOOutput}, which passes them on to \ttt{FeynmanRules}.
 
 \begin{description}
 \item[\ttt{Input}]\mbox{}\\
 An optional vertex list to use instead of a Lagrangian (which can then be
 omitted).
 %
 \item[\ttt{WOWhizardVersion}]\mbox{}\\
 Select the \whizard\ version for which code is to be generated.
 The currently available choices are summarized in
 Tab.~\ref{tab-wowhizardversion}.
 %%
 \begin{table}
 \centerline{\begin{tabular}{|l|l|}
 \hline \ttt{WOWhizardVersion} & \whizard\ versions supported
 \\\hline\hline
 \ttt{"2.0.3"} (default) & 2.0.3+ \\\hline
 \ttt{"2.0"} & 2.0.0 -- 2.0.2 \\\hline\hline
 \ttt{"1.96"} & 1.96+ \qquad (deprecated) \\\hline
 \ttt{"1.93"} & 1.93 -- 1.95 \qquad (deprecated) \\\hline
 \ttt{"1.92"} & 1.92 \qquad (deprecated) \\\hline
 \end{tabular}}
 \caption{Currently available choices for the \ttt{WOWhizardVersion} option,
 together with the respective \whizard\ versions supported by them.}
 \label{tab-wowhizardversion}
 \end{table}
 %%
 This list  will expand as the program evolves. To get a summary
 of all choices available in a particular version of the interface, use
 the command
 \ttt{?WOWhizardVersion}.
 %
 \item[\ttt{WOModelName}]\mbox{}\\
 The name under which the model will be known to
 \whizard\footnote{For versions 1.9x, model names must start
   with ``\ttt{fr\_}'' if they are to be picked up by \whizard\
   automatically.}. The default is determined from the \FeynRules\
 model name.
 %
 \item[\ttt{Output}]\mbox{}\\
 The name of the output directory. The default is determined from the
 \FeynRules\ model name.
 %
 \item[\ttt{WOGauge}]\mbox{}\\
 Gauge choice (\emph{cf.} Sec.~\ref{sec:gauge-choices}).
 Possible values are: \ttt{WOUnitarity} (default),
 \ttt{WOFeynman}, \ttt{WORxi}
 %
 \item[\ttt{WOGaugeParameter}]\mbox{}\\
 The external or internal parameter representing the gauge $\xi$ in
 the $R_\xi$ gauges (\emph{cf.} Sec.~\ref{sec:gauge-choices}). Default:
 \ttt{Rxi}
 %
 \item[\ttt{WOAutoGauge}]\mbox{}\\
 Automatically assign the Goldstone boson masses in the Feynman and $R_\xi$
 gauges and automatically append the symbol for $\xi$ to the parameter list in
 the $R_\xi$ gauges. Default: \ttt{False}
 %
 \item[\ttt{WORunParameters}]\mbox{}\\
 The list of all internal parameters which will be recalculated if $\alpha_S$ is
 evolved (see above)\footnote{Not available for versions older than
   2.0.0}. Default: \mbox{\ttt{\{aS, G\}}}
 %
 \item[\ttt{WOFast}]\mbox{}\\
 If the interface drops vertices which are supported, this option can be
 set to \ttt{False} to enable some more time consuming checks which might aid
 the identification. Default: \ttt{True}
 %
 \item[\ttt{WOMaxCouplingsPerFile}]\mbox{}\\
 The maximum number of couplings that are written to a single \fortran\
 file. If compilation takes too long or fails, this can be
 lowered. Default: \ttt{500}
 %
 \item[\ttt{WOVerbose}]\mbox{}\\
 Enable verbose output and in particular more extensive information on any
 skipped vertices. Default: \ttt{False}
 \end{description}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \subsection{Validation of the interface}
 
 The output of the interface has been extensively
 validated. Specifically, the integrated cross sections for all
 possible $2\rightarrow 2$ processes in the \FeynRules\ SM, the MSSM
 and the Three-Site Higgsless Model have been compared between
 \whizard, \madgraph, and \CalcHep, using the respective \FeynRules\
 interfaces as well as the in-house implementations of these models
 (the Three-Site Higgsless model not being available in \madgraph).
 Also, different gauges have been checked for \whizard\ and \CalcHep.
 In all comparisons, excellent agreement within the Monte Carlo errors
 was achieved. The detailed comparison including examples of the
 comparison tables can be found in~\cite{Christensen:2010wz}.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \subsection{Examples for the \whizard-/\FeynRules\ interface}
 
 Here, we will use the Standard Model, the MSSM and the Three-Site
 Higgsless Model as prime examples to explain the usage of the
 interface. Those are the models that have been used in the validation
 of the interface in~\cite{Christensen:2010wz}. The examples are
 constructed to show the application of the different options of the
 interface and to serve as a starting point for the generation of the
 user's own \whizard\ versions of other \FeynRules\ models.
 
 \subsubsection{\whizard-\FeynRules\ example: Standard
   Model}\label{sec:usageSM}
 
 To start off, we will create {\sc Whizard} 2 versions of the Standard
 Model as implemented in \FeynRules\ for different gauge choices.
 
 \paragraph{SM: Unitarity Gauge}
 
 In order to invoke \FeynRules, we change to the corresponding
 directory and load the program in \Mathematica\ via
 \begin{code}
 $FeynRulesPath =
      SetDirectory["<path-to-FeynRules>"];
 <<FeynRules`
 \end{code}
 %$
 The model is loaded by
 \begin{code}
 LoadModel["Models/SM/SM.fr"];
 FeynmanGauge = False;
 \end{code}
 Note that the second line is required to switch the Standard
 Model to Unitarity gauge as opposed to Feynman gauge (which is the default).
 Generating a \whizard\ model is now simply done by
 \begin{code}
 WriteWOOutput[LSM];
 \end{code}
 After invokation, the interface first gives a short summary of the setup
 \begin{code}
 Short model name is "fr_standard_model"
 Gauge: Unitarity
 Generating code for WHIZARD / O'Mega
                         version 2.0.3
 Maximum number of couplings per FORTRAN
                            module: 500
 Extensive lorentz structure checks disabled.
 \end{code}
 
 Note that, as we have not changed any options, those settings represent the
 defaults. The output proceeds with the calculation of the Feynman rules from the
 Standard Model Lagrangian \verb?LSM?. After the rules have been derived, the
 interface starts generating output and tries to match the vertices to
 their \whizard/\oMega\ counterparts.
 \begin{code}
    10 of 75 vertices processed...
    20 of 75 vertices processed...
    30 of 75 vertices processed...
    40 of 75 vertices processed...
    50 of 75 vertices processed...
    60 of 75 vertices processed...
    70 of 75 vertices processed...
 processed a total of 75 vertices, kept 74
    of them and threw away 1, 1 of which
    contained ghosts or goldstone bosons.
 \end{code}
 The last line of the above output is particularily interesting, as it informs us
 that everything worked out correctly: the interface was able to match all
 vertices, and the only discarded vertex was the QCD ghost interaction.
 After the interface has finished running, the model files in the output
 directory are ready to use and can be compiled using the procedure described in
 the previous section.
 
 %%%%%
 
 \paragraph{SM: Feynman and $R_\xi$ gauges}
 
 As the Standard Model as implemented in \FeynRules\ also supports Feynman
 gauge, we can use the program to generate a Feynman gauge version of the model.
 Loading \FeynRules\ and the model proceeds as above, with the only
 difference being the change
 \begin{code}
 FeynmanGauge = True;
 \end{code}
 In order to inform the interface about the modified gauge, we have to
 add the option \verb?WOGauge?
 \begin{code}
 WriteWOOutput[LSM, WOGauge -> WOFeynman];
 \end{code}
 The modified gauge is reflected in the output of the interface
 \begin{code}
 Short model name is "fr_standard_model"
 Gauge: Feynman
 Generating code for WHIZARD / O'Mega
                         version 2.0.3
 Maximum number of couplings per FORTRAN
                            module: 500
 Extensive lorentz structure checks disabled.
 \end{code}
 The summary of the vertex identification now takes the following form
 \begin{code}
 processed a total of 163 vertices, kept 139
    of them and threw away 24, 24 of which
    contained ghosts.
 \end{code}
 Again, this line tells us that there were no problems --- the only
 discarded interactions involved the ghost sector which is irrelevant
 for the tree-level part of \whizard.
 
 For a tree-level calculation, the only difference between the
 different gauges from the perspective of the interface are the gauge
 boson propagators and the Goldstone boson masses. Therefore, the
 interface can automatically convert a model in Feynman gauge to a
 model in $R_\xi$ gauge. To this end, the call to the interface must be
 changed to
 \begin{code}
 WriteWOOutput[LSM, WOGauge -> WORxi,
                WOAutoGauge -> True];
 \end{code}
 The \verb?WOAutoGauge? argument instructs the interface to
 automatically
 \begin{enumerate}
 \item Introduce a symbol for the gauge parameter $\xi$ into the
 list of external parameters
 \item Generate the Goldstone boson masses from those of the associated
   gauge bosons (ignoring the values provided by \FeynRules)
 \end{enumerate}
 The modified setup is again reflected in the interface output
 \begin{code}
 Short model name is "fr_standard_model"
 Gauge: Rxi
 Gauge symbol: "Rxi"
 Generating code for WHIZARD / O'Mega
                        version 2.0.3
 Maximum number of couplings per FORTRAN
                          module: 500
 Extensive lorentz structure checks disabled.
 \end{code}
 Note the default choice \verb?Rxi? for the name of the $\xi$ parameter
 -- this can be modified via the option \verb?WOGaugeParameter?.
 
 While the \verb?WOAutoGauge? feature allows to generate $R_\xi$ gauged models
 from models implemented in Feynman gauge, it is of course also possible to use
 models genuinely implemented in $R_\xi$ gauge by setting this parameter to
 \verb?False?. Also, note that the choice of gauge only affects the propagators
 of massive fields. Massless gauge bosons are always treated in Feynman
 gauge.
 
 \paragraph{Compilation and usage}
 
 In order to compile and use the freshly generated model files, change to the
 output directory which can be determined from the interface output (in this
 example, it is \verb?fr_standard_model-WO?). Assuming that \whizard\ is
 available in the binary search path, compilation and installation proceeds as
 described above by executing
 \begin{code}
 ./configure && make && make install
 \end{code}
 The model is now ready and can be used similarly to the builtin
 \whizard\ models. For example, a minimal \whizard\ input file for
 calculating the $e^+e^- \longrightarrow W^+W^-$ scattering cross
 section in the freshly generated model would look like
 \begin{code}
 model = fr_standard_model
 process test = "e+", "e-" -> "W+", "W-"
 sqrts = 500 GeV
 integrate (test)
 \end{code}
 
 %%%%%
 
 \subsubsection{\whizard/\FeynRules\ example: MSSM}
 In this Section, we illustrate the usage of the interface between {\sc
 FeynRules} and {\sc Whizard} in the context of the MSSM. All the
 parameters of the model are then ordered in Les Houches blocks and
 counters following the SUSY Les Houches Accord (SLHA)
 \cite{Skands:2003cj,AguilarSaavedra:2005pw,Allanach:2008qq} (cf. also
 Sec.~\ref{sec:slha}).
 
 After having downloaded the model
 from the \FeynRules\ website, we store it in a new directory, labelled
 \verb"MSSM", of the model library of the local installation of
 \FeynRules. The model can then be loaded in \Mathematica\ as in the
 case of the SM example above
 \begin{code}
 $FeynRulesPath =
         SetDirectory["<path-to-FeynRules>"];
 <<FeynRules`
 LoadModel["Models/MSSM/MSSM.fr"];
 FeynmanGauge = False;
 \end{code}
 %$
 We are again adopting unitarity gauge.
 
 The number of vertices associated to supersymmetric Lagrangians is in general
 very large (several thousands). For such models with many interactions,
 it is recommended to first extract all the Feynman rules of the theory before
 calling the interface between \whizard\ and \FeynRules.
 The reason is related to the efficiency of the interface  which takes
 a lot of time in the extraction of the interaction vertices. In the
 case one wishes to study the phenomenology of several benchmark
 scenarios, this procedure, which is illustrated below,
 allows to use the interface in the best way. The Feynman rules
 are derived from the Lagrangian once and for all and then reused by the
 interface for each set of \whizard\ model files to be produced,
 considerably  speeding up the generation of multiple model files
 issued from a single Lagrangian. In addition, the scalar potential of
 supersymmetric theories contains a large set of four scalar
 interactions, in general irrelevant for collider phenomenology. These
 vertices can be neglected with the help of the
 \verb"Exclude4Scalars->True" option of both interface commands
 \verb"FeynmanRules" and \verb"WriteWOOutput". The Feynman
 rules of the MSSM are then computed within the \Mathematica\ notebook
 by
 \begin{code}
 rules = FeynmanRules[lag,
    Exclude4Scalars->True, FlavorExpand->True];
 \end{code}
 where \verb'lag' is the variable containing the Lagrangian.
 
 By default, all the parameters of the model are set to the value of
 \ttt{1}. A complete parameter \ttt{{\em <slha\_params>}.dat} file
 must therefore be loaded. Such a parameter file can be downloaded from
 the \FeynRules\ website or created by hand by the user, and loaded
 into \FeynRules\ as
 \begin{code}
 ReadLHAFile[Input -> "<slha_params>.dat"];
 \end{code}
 This command does not reduce the size of the model output by removing
 vertices with vanishing couplings.  However, if desired, this task
 could be done with the  \ttt{LoadRestriction} command (see Ref.\
 \cite{Fuks:2012im} for details).
 
 The vertices are exported to \whizard\ by the command
 \begin{code}
 WriteWOOutput[Input -> rules];
 \end{code}
 Note that the numerical values of the parameters of the model can be
 modified directly from \whizard, without having to generate a second
 time the \whizard\ model files from \FeynRules. A \sindarin\ script is
 created by the interface with the help of the instruction
 \begin{code}
 WriteWOExtParams["parameters.sin"];
 \end{code}
 and can be further modified according to the needs of the user.
 
 \subsubsection{\whizard-\FeynRules\ example: Three-Site Higgsless Model}
 
 
 The Three-Site Higgsless model or Minimal Higgsless model (MHM) has
 been implemented into \ttt{LanHEP}~\cite{He:2007ge}, \FeynRules\
 and independently into \whizard~\cite{Speckner:2010zi},
 and the collider phenomenology has been studied by making use of these
 implementations \cite{He:2007ge,Ohl:2010zf,Speckner:2010zi}.
 Furthermore, the independent implementations in \FeynRules\ and
 directly into {\sc Whizard} have been compared and found to
 agree~\cite{Christensen:2010wz}. After the discovery of a Higgs boson
 at the LHC in 2012, such a model is not in good agreement with
 experimental data any more. Here, we simply use it as a guinea pig to
 describe the handling of a model with non-renormalizable interactions
 with the \FeynRules\ interface, and discuss how to generate \whizard\
 model files for it. The model has been implemented in Feynman gauge as
 well as unitarity gauge and contains the variable \verb|FeynmanGauge|
 which can be set to \verb|True|  or \verb|False|. When set to
 \verb|True|, the option \verb|WOGauge-> WOFeynman| must be used, as
 explained in~\cite{Christensen:2010wz}. $R_\xi$ gauge can also be
 accomplished with this model by use of the options
 \verb|WOGauge -> WORxi| and \verb?WOAutoGauge -> True?.
 
 Since this model makes use of a nonlinear sigma field of the form
 \begin{equation}
 \Sigma = 1 + i\pi - \frac{1}{2}\pi^2+\cdots
 \end{equation}
 many higher dimensional operators are included in the model which are
 not currently not supported by \whizard. Even for a future release of
 \whizard\ containing general Lorentz structures in interaction
 vertices, the user would be forced to expand the series only up to a
 certain order. Although \whizard\ can reject these vertices
 and print a warning message to the user, it is preferable to remove
 the vertices right away in the interface by the option
 \verb|MaxCanonicalDimension->4|. This is passed to the command
 \verb|FeynmanRules| and restricts the Feynman rules to those of
 dimension four and smaller\footnote{\ttt{MaxCanonicalDimension} is an
   option of the \ttt{FeynmanRules} function rather than of the
   interface, itself. In fact, the interface accepts all the options of
   {\tt FeynmanRules} and simply passes them on to the latter.}.
 
 As the use of different gauges was already illustrated in the SM
 example, we discuss the model only in Feynman gauge here. We load
 \FeynRules:
 \begin{code}
 $FeynRulesPath =
      SetDirectory["<path-to-FeynRules>"];
 <<FeynRules`
 \end{code}
 %$
 The MHM model itself is then loaded by
 \begin{code}
 SetDirectory["<path-to-MHM>"];
 LoadModel["3-Site-particles.fr",
    "3-Site-parameters.fr",
    "3-Site-lagrangian.fr"];
 FeynmanGauge = True;
 \end{code}
 where \verb|<path-to-MHM>| is the path to the directory where the MHM
 model files are stored and where the output of the \whizard\
 interface will be written. The \whizard\ interface is then initiated:
 \begin{code}
 WriteWOOutput[LGauge, LGold, LGhost, LFermion,
    LGoldLeptons, LGoldQuarks,
    MaxCanonicalDimension->4,
    WOGauge->WOFeynman, WOModelName->"fr_mhm"];
 \end{code}
 where we have also made use of the option \verb|WOModelName| to change
 the name of the model as seen by \whizard. As in the case of the SM,
 the interface begins by writing a short informational message:
 \begin{code}
 Short model name is "fr_mhm"
 Gauge: Feynman
 Generating code for WHIZARD / O'Mega
                        version 2.0.3
 Automagically assigning Goldstone
                         boson masses...
 Maximum number of couplings per FORTRAN
                         module: 500
 Extensive lorentz structure checks disabled.
 \end{code}
 After calculating the Feynman rules and processing the vertices, the
 interface gives a summary:
 \begin{code}
 processed a total of 922 vertices, kept 633
   of them and threw away 289, 289 of which
   contained ghosts.
 \end{code}
 showing that no vertices were missed.  The files are stored in the
 directory \verb|fr_mhm| and are ready to be installed and used with
 \whizard.
 
 %%%%%%%%%%%%%%%
 
 \section{New physics models via the \UFO\ file format}
 \label{sec:ufo}
 
 In this section, we describe how to use the {\em Universal FeynRules
 Output} (\UFO, \cite{Degrande:2011ua}) format for physics models
 inside \whizard. Please refer the manuals of e.g.~\FeynRules\ manual
 for details on how to generate a \UFO\ file for your favorite physics
 model. \UFO\ files are a collection of \ttt{Python} scripts that
 encode the particles, the couplings, the Lorentz structures, the
 decays, as well as parameters, vertices and propagators of the
 corresponding model. They reside in a directory of the exact name of
 the model they have been created from.
 
 If the user wants to generate events for processes from a physics
 model from a \UFO\ file, then this directory of scripts generated by
 \FeynRules\ is immediately available if it is a subdirectory of the working
 directory of \whizard.  The directory name will be taken as the model
 name. (The \UFO-model file name must not start with a
   non-letter character, i.e. especially not a number.  In case such a
   file name wants to be used at all costs, the model name in the
   \sindarin\ script has to put in quotation marks, but this is not
   guaranteed to always work.)  Then, a \UFO\ model named, e.g.,
 \ttt{test\_model} is accessed by an extra \ttt{ufo} tag in the model
 assignment:
 \begin{Code}
   model = test_model (ufo)
 \end{Code}
 
 If desired, \whizard\ can access a directory of \UFO\ files elsewhere
 on the file system.  For instance, if \FeynRules\ output resides in
 the subdirectory \ttt{MyMdl} of
 \ttt{/home/users/john/ufo}, \whizard\ can use the model
 named \ttt{MyMdl} as follows
 \begin{Code}
   model = MyMdl (ufo ('/home/users/john/my_ufo_models'))
 \end{Code}
 that is, the \sindarin\ keyword \ttt{ufo} can take an argument.  Note
 however, that the latter approach can backfire --- in case just the working
 directory is packed and archived for future reference.
 
 %%%%%%%%%%%%%%%
 
 
 
 \clearpage
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \appendix
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \chapter{\sindarin\ Reference}
 
 In the \sindarin\ language, there are certain pre-defined constructors or
 commands that cannot be used in different context by the user, which
 are e.g. \ttt{alias}, \ttt{beams}, \ttt{integrate}, \ttt{simulate} etc.
 A complete list will be given below. Also units are fixed, like
 \ttt{degree}, \ttt{eV}, \ttt{keV},
 \ttt{MeV}, \ttt{GeV}, and \ttt{TeV}. Again, these tags are locked and
 not user-redefinable. Their functionality will be listed in detail
 below, too. Furthermore, a variable with a preceding
 question mark, ?, is a logical, while a preceding dollar, \$, denotes a
 character string variable.  Also, a lot of unary and binary operators
 exist, \ttt{+ - $\backslash$ , = : => < > <= >= \^ \;  () [] \{\} }
 \url{==}, as well as quotation marks, ". Note that the
 different parentheses and brackets fulfill different purposes, which
 will be explained below. Comments in a line can either be marked by a
 hash, \#, or an exclamation mark, !.
 
 \section{Commands and Operators}
 We begin the \sindarin\ reference with all commands, operators, functions
 and constructors.
 The list of variables (which can be set to change behavior of \whizard) can
 be found in the next section.
 \begin{itemize}
 \item
 \ttt{+} \newline
 1) Arithmetic operator for addition of integers, reals and complex
 numbers. Example: \ttt{real mm = mH + mZ} (cf. also \ttt{-}, \ttt{*},
 \ttt{/}, \ttt{\^{}}). 2) It also adds different particles for inclusive
 process containers: \ttt{process foo = e1, E1 => (e2, E2) + (e3,
   E3)}. 3) It also serves as a shorthand notation for the
 concatenation of ($\to$) \ttt{combine} operations on
 particles/subevents, e.g. \ttt{cuts = any 170 GeV < M < 180 GeV [b +
   lepton + invisible]}.
 %%%%%
 \item
 \ttt{-} \newline
 Arithmetic operator for subtraction of integers, reals and complex
 numbers. Example: \ttt{real foo = 3.1 - 5.7} (cf. also \ttt{+}, \ttt{*},
 \ttt{/}, \ttt{\^{}}).
 %%%%%
 \item
 \ttt{/} \newline
 Arithmetic operator for division of integers, reals and complex
 numbers. Example: \ttt{scale = mH / 2} (cf. also \ttt{+}, \ttt{*},
 \ttt{-}, \ttt{\^{}}).
 %%%%%
 \item
 \ttt{*} \newline
 Arithmetic operator for multiplication of integers, reals and complex
 numbers. Example: \ttt{complex z = 2 * I} (cf. also \ttt{+}, \ttt{/},
 \ttt{-}, \ttt{\^{}}).
 %%%%%
 \item
 \ttt{\^{}} \newline
 Arithmetic operator for exponentiation of integers, reals and complex
 numbers. Example: \ttt{real z = x\^{}2 + y\^{}2} (cf. also \ttt{+},
 \ttt{/}, \ttt{-}, \ttt{\^{}}).
 %%%%%
 \item
 \ttt{<} \newline
 Arithmetic comparator between values that checks for ordering
 of two values: \ttt{{\em <val1>} < {\em <val2>}} tests whether
 \ttt{{\em val1}} is smaller than \ttt{{\em val2}}. Allowed for
 integer and real values. Note that this is an exact comparison if
 \ttt{tolerance} is set to zero. For a finite value of \ttt{tolerance}
 it is a ``fuzzy'' comparison. (cf. also \ttt{tolerance}, \ttt{<>},
 \ttt{==}, \ttt{>}, \ttt{>=}, \ttt{<=})
 %%%%%
 \item
 \ttt{>} \newline
 Arithmetic comparator between values that checks for ordering
 of two values: \ttt{{\em <val1>} > {\em <val2>}} tests whether
 \ttt{{\em val1}} is larger than \ttt{{\em val2}}. Allowed for
 integer and real values. Note that this is an exact comparison if
 \ttt{tolerance} is set to zero. For a finite value of \ttt{tolerance}
 it is a ``fuzzy'' comparison. (cf. also \ttt{tolerance}, \ttt{<>},
 \ttt{==}, \ttt{>}, \ttt{>=}, \ttt{<=})
 %%%%%
 \item
 \ttt{<=} \newline
 Arithmetic comparator between values that checks for ordering
 of two values: \ttt{{\em <val1>} <= {\em <val2>}} tests whether
 \ttt{{\em val1}} is smaller than or equal \ttt{{\em val2}}. Allowed for
 integer and real values. Note that this is an exact comparison if
 \ttt{tolerance} is set to zero. For a finite value of \ttt{tolerance}
 it is a ``fuzzy'' comparison. (cf. also \ttt{tolerance}, \ttt{<>},
 \ttt{==}, \ttt{>}, \ttt{<}, \ttt{>=})
 %%%%%
 \item
 \ttt{>=} \newline
 Arithmetic comparator between values that checks for ordering
 of two values: \ttt{{\em <val1>} >= {\em <val2>}} tests whether
 \ttt{{\em val1}} is larger than or equal \ttt{{\em val2}}. Allowed for
 integer and real values. Note that this is an exact comparison if
 \ttt{tolerance} is set to zero. For a finite value of \ttt{tolerance}
 it is a ``fuzzy'' comparison. (cf. also \ttt{tolerance}, \ttt{<>},
 \ttt{==}, \ttt{>}, \ttt{<}, \ttt{>=})
 %%%%%
 \item
 \ttt{==} \newline
 Arithmetic comparator between values that checks for identity
 of two values: \ttt{{\em <val1>} == {\em <val2>}}. Allowed for
 integer and real values. Note that this is an exact comparison if
 \ttt{tolerance} is set to zero. For a finite value of \ttt{tolerance}
 it is a ``fuzzy'' comparison. (cf. also \ttt{tolerance}, \ttt{<>},
 \ttt{>}, \ttt{<}, \ttt{>=}, \ttt{<=})
 %%%%%
 \item
 \ttt{<>} \newline
 Arithmetic comparator between values that checks for
 two values being unequal: \ttt{{\em <val1>} <> {\em <val2>}}. Allowed for
 integer and real values. Note that this is an exact comparison if
 \ttt{tolerance} is set to zero. For a finite value of \ttt{tolerance}
 it is a ``fuzzy'' comparison. (cf. also \ttt{tolerance}, \ttt{==},
 \ttt{>}, \ttt{<}, \ttt{>=}, \ttt{<=})
 %%%%%
 \item
 \ttt{!} \newline
 The exclamation mark tells \sindarin\ that everything that follows in
 that line should be treated as a comment. It is the same as ($\to$)
 \ttt{\#}.
 %%%%%
 \item
 \ttt{\#} \newline
 The hash tells \sindarin\ that everything that follows in
 that line should be treated as a comment. It is the same as ($\to$)
 \ttt{!}.
 %%%%%
 \item
 \ttt{\&} \newline
 Concatenates two or more particle lists/subevents and hence acts in
 the same way as the subevent function ($\to$) \ttt{join}: \ttt{let
 @visible = [photon] \& [colored] \& [lepton] in ...}. (cf. also
 \ttt{join}, \ttt{combine}, \ttt{collect}, \ttt{extract}, \ttt{sort}).
 %%%%%
 \item
 \ttt{\$} \newline
 Constructor at the beginning of a variable name,
 \ttt{\${\em <string\_var>}}, that specifies a string variable.
 %%%%%
 \item
 \ttt{@} \newline
 Constructor at the beginning of a variable name, \ttt{@{\em
 <subevt\_var>}}, that specifies a subevent variable, e.g. \ttt{let
 @W\_candidates = combine ["mu-", "numubar"] in ...}.
 %%%%%
 \item
 \ttt{=} \newline
 Binary constructor to appoint values to commands, e.g. \ttt{{\em <command>}
   = {\em <expr>}} or \newline \ttt{{\em <command>} {\em <var\_name>} =
   {\em <expr>}}.
 %%%%%
 \item
 \ttt{\%} \newline
 Constructor that gives the percentage of a number, so in
 principle multiplies a real number by \ttt{0.01}. Example: \ttt{1.23
   \%} is equal to \ttt{0.0123}.
 %%%%%
 \item
 \ttt{:} \newline
 Separator in alias expressions for particles, e.g. \ttt{alias neutrino
   = n1:n2:n3:N1:N2:N3}. (cf. also \ttt{alias})
 %%%%%
 \item
 \ttt{;} \newline
 Concatenation operator for logical expressions: \ttt{{\em lexpr1} ;
   {\em lexpr2}}. Evaluates \ttt{{\em lexpr1}} and throws the result
 away, then evaluates \ttt{{\em lexpr2}} and returns that result. Used
 in analysis expressions. (cf. also \ttt{analysis}, \ttt{record})
 %%%%%
 \item
 \ttt{/+} \newline
 Incrementor for ($\to$) \ttt{scan} ranges, that increments additively,
 \ttt{scan {\em <num\_spec> <num>} = ({\em <lower val>} => {\em <upper
     val>} /+ {\em <step
 size>})}. E.g. \ttt{scan int i = (1 => 5 /+ 2)} scans over the values \ttt{1},
 \ttt{3}, \ttt{5}. For real ranges, it divides the interval between
 upper and lower bound into as many intervals as the incrementor
 provides, e.g. \ttt{scan real r = (1 => 1.5 /+ 0.2)} runs over
 \ttt{1.0}, \ttt{1.333}, \ttt{1.667}, \ttt{1.5}.
 %%%%%
 \item
 \ttt{/+/} \newline
 Incrementor for ($\to$) \ttt{scan} ranges, that increments additively,
 but the number after the incrementor is the number of steps, not the
 step size: \ttt{scan {\em <num\_spec> <num>} = ({\em <lower val>} =>
   {\em <upper val>}
 /+/ {\em <steps>})}. It is only available for real scan ranges, and divides
 the interval \ttt{{\em <upper val>} - {\em <lower val>}} into
 \ttt{{\em <steps>}} steps,
 e.g. \ttt{scan real r = (1 => 1.5 /+/ 3)} runs over \ttt{1.0},
 \ttt{1.25}, \ttt{1.5}.
 %%%%%
 \item
 \ttt{/-} \newline
 Incrementor for ($\to$) \ttt{scan} ranges, that increments subtractively,
 \ttt{scan {\em <num\_spec>} {\em <num>} = ({\em <lower val>} => {\em <upper val>} /- {\em <step
 size>})}. E.g. \ttt{scan int i = (9 => 0 /+ 3)} scans over the values \ttt{9},
 \ttt{6}, \ttt{3}, \ttt{0}. For real ranges, it divides the interval
 between upper and lower bound into as many intervals as the incrementor
 provides, e.g. \ttt{scan real r = (1 => 0.5 /- 0.2)} runs over
 \ttt{1.0}, \ttt{0.833}, \ttt{0.667}, \ttt{0.5}.
 %%%%%
 \item
 \ttt{/*} \newline
 Incrementor for ($\to$) \ttt{scan} ranges, that increments multiplicatively,
 \ttt{scan {\em <num\_spec>} {\em <num>} = ({\em <lower val>} => {\em <upper val>} /* {\em <step
 size>})}. E.g. \ttt{scan int i = (1 => 4 /* 2)} scans over the values \ttt{1},
 \ttt{2}, \ttt{4}. For real ranges, it divides the interval
 between upper and lower bound into as many intervals as the incrementor
 provides, e.g. \ttt{scan real r = (1 => 5 /* 2)} runs over
 \ttt{1.0}, \ttt{2.236} (i.e. $\sqrt{5}$), \ttt{5.0}.
 %%%%%
 \item
 \ttt{/*/} \newline
 Incrementor for ($\to$) \ttt{scan} ranges, that increments multiplicatively,
 but the number after the incrementor is the number of steps, not the
 step size: \ttt{scan {\em <num\_spec>} {\em <num>} = ({\em <lower val>} => {\em <upper val>}
 /*/ {\em <steps>})}. It is only available for real scan ranges, and divides
 the interval \ttt{{\em <upper val>} - {\em <lower val>}} into \ttt{{\em <steps>}} steps,
 e.g. \ttt{scan real r = (1 => 9 /*/ 4)} runs over \ttt{1.000},
 \ttt{2.080}, \ttt{4.327}, \ttt{9.000}.
 %%%%%
 \item
 \ttt{//} \newline
 Incrementor for ($\to$) \ttt{scan} ranges, that increments by division,
 \ttt{scan {\em <num\_spec>} {\em <num>} = ({\em <lower val>} => {\em <upper val>} // {\em <step
 size>})}. E.g. \ttt{scan int i = (13 => 0 // 3)} scans over the values \ttt{13},
 \ttt{4}, \ttt{1}, \ttt{0}. For real ranges, it divides the interval
 between upper and lower bound into as many intervals as the incrementor
 provides, e.g. \ttt{scan real r = (5 => 1 // 2)} runs over
 \ttt{5.0}, \ttt{2.236} (i.e. $\sqrt{5}$), \ttt{1.0}.
 %%%%%
 \item
 \ttt{=>} \newline
 Binary operator that is used in several different contexts: 1) in
 process declarations between the particles specifying the
 initial and final state, e.g. \ttt{process {\em <proc\_name>} = {\em <in1>}, {\em <in2>}
 => {\em <out1>}, ....}; 2) for the specification of beams when
 structure functions are applied to the beam particles, e.g. \ttt{beams
 = p, p => pdf\_builtin}; 3) for the specification of the scan range in
 the \ttt{scan {\em <var>} {\em <var\_name>} = ({\em <scan\_start>} => {\em <scan\_end>}
   {\em <incrementor>})} (cf. also \ttt{process}, \ttt{beams}, \ttt{scan})
 %%%%%
 \item
 \ttt{\%d} \newline
 Format specifier in analogy to the \ttt{C} language for the print out
 on screen by the ($\to$) \ttt{printf} or into strings by the ($\to$)
 \ttt{sprintf} command. It is used for decimal integer numbers,
 e.g. \ttt{printf "one = \%d" (i)}. The difference between \ttt{\%i}
 and \ttt{\%d} does not play a role here. (cf. also \ttt{printf}, \ttt{sprintf},
 \ttt{\%i}, \ttt{\%e}, \ttt{\%f}, \ttt{\%g}, \ttt{\%E}, \ttt{\%F},
 \ttt{\%G}, \ttt{\%s})
 %%%%%
 \item
 \ttt{\%e} \newline
 Format specifier in analogy to the \ttt{C} language for the print out
 on screen by the ($\to$) \ttt{printf} or into strings by the ($\to$)
 \ttt{sprintf} command. It is used for floating-point numbers in
 standard form \ttt{[-]d.ddd e[+/-]ddd}. Usage e.g. \ttt{printf "pi =
 \%e" (PI)}.  (cf. also \ttt{printf}, \ttt{sprintf},
 \ttt{\%d}, \ttt{\%i}, \ttt{\%f}, \ttt{\%g}, \ttt{\%E}, \ttt{\%F},
 \ttt{\%G}, \ttt{\%s})
 %%%%%
 \item
 \ttt{\%E} \newline
 Same as ($\to$) \ttt{\%e}, but using upper-case letters.  (cf. also
 \ttt{printf}, \ttt{sprintf}, \ttt{\%d}, \ttt{\%i}, \ttt{\%e}, \ttt{\%f},
 \ttt{\%g}, \ttt{\%F}, \ttt{\%G}, \ttt{\%s})
 %%%%%
 \item
 \ttt{\%f} \newline
 Format specifier in analogy to the \ttt{C} language for the print out
 on screen by the ($\to$) \ttt{printf} or into strings by the ($\to$)
 \ttt{sprintf} command. It is used for floating-point numbers in
 fixed-point form. Usage e.g. \ttt{printf "pi =
 \%f" (PI)}.  (cf. also \ttt{printf}, \ttt{sprintf},
 \ttt{\%d}, \ttt{\%i}, \ttt{\%e}, \ttt{\%g}, \ttt{\%E}, \ttt{\%F},
 \ttt{\%G}, \ttt{\%s})
 %%%%%
 \item
 \ttt{\%F} \newline
 Same as ($\to$) \ttt{\%f}, but using upper-case letters.  (cf. also
 \ttt{printf}, \ttt{sprintf}, \ttt{\%d}, \ttt{\%i}, \ttt{\%e}, \ttt{\%f},
 \ttt{\%g}, \ttt{\%E}, \ttt{\%G}, \ttt{\%s})
 %%%%%
 \item
 \ttt{\%g} \newline
 Format specifier in analogy to the \ttt{C} language for the print out
 on screen by the ($\to$) \ttt{printf} or into strings by the ($\to$)
 \ttt{sprintf} command. It is used for floating-point numbers in
 normal or exponential notation, whichever is more approriate. Usage
 e.g. \ttt{printf "pi = \%g" (PI)}.  (cf. also \ttt{printf}, \ttt{sprintf},
 \ttt{\%d}, \ttt{\%i}, \ttt{\%e}, \ttt{\%f}, \ttt{\%E}, \ttt{\%F},
 \ttt{\%G}, \ttt{\%s})
 %%%%%
 \item
 \ttt{\%G} \newline
 Same as ($\to$) \ttt{\%g}, but using upper-case letters.  (cf. also
 \ttt{printf}, \ttt{sprintf}, \ttt{\%d}, \ttt{\%i}, \ttt{\%e}, \ttt{\%f},
 \ttt{\%g}, \ttt{\%E}, \ttt{\%F}, \ttt{\%s})
 %%%%%
 \item
 \ttt{\%i} \newline
 Format specifier in analogy to the \ttt{C} language for the print out
 on screen by the ($\to$) \ttt{printf} or into strings by the ($\to$)
 \ttt{sprintf} command. It is used for integer numbers,
 e.g. \ttt{printf "one = \%i" (i)}. The difference between \ttt{\%i}
 and \ttt{\%d} does not play a role here. (cf. \ttt{printf}, \ttt{sprintf},
 \ttt{\%d}, \ttt{\%e}, \ttt{\%f}, \ttt{\%g}, \ttt{\%E}, \ttt{\%F},
 \ttt{\%G}, \ttt{\%s})
 %%%%%
 \item
 \ttt{\%s} \newline
 Format specifier in analogy to the \ttt{C} language for the print out
 on screen by the ($\to$) \ttt{printf} or into strings by the ($\to$)
 \ttt{sprintf} command. It is used for logical or string variables
 e.g. \ttt{printf "foo = \%s" (\$method)}. (cf. \ttt{printf}, \ttt{sprintf},
 \ttt{\%d}, \ttt{\%i}, \ttt{\%e}, \ttt{\%f}, \ttt{\%g}, \ttt{\%E}, \ttt{\%F},
 \ttt{\%G})
 %%%%%
 \item
 \ttt{abarn} \newline
 Physical unit, stating that a number is in attobarns ($10^{-18}$
 barn). (cf. also \ttt{nbarn}, \ttt{fbarn}, \ttt{pbarn})
 %%%%%
 \item
 \ttt{abs} \newline
 Numerical function that takes the absolute value of its argument:
 \ttt{abs ({\em <num\_val>})} yields \ttt{|{\em
 <num\_val>}|}. (cf. also \ttt{conjg}, \ttt{sgn}, \ttt{mod}, \ttt{modulo})
 %%%%%
 \item
 \ttt{acos} \newline
 Numerical function \ttt{asin ({\em <num\_val>})} that calculates the
 arccosine trigonometric function (inverse of \ttt{cos}) of real and
 complex numerical numbers or variables. (cf. also \ttt{sin},
 \ttt{cos}, \ttt{tan}, \ttt{asin}, \ttt{atan})
 %%%%%
 \item
 \ttt{alias} \newline
 This allows to define a collective expression for a class of
 particles, e.g. to define a generic expression for leptons, neutrinos
 or a jet as \ttt{alias lepton = e1:e2:e3:E1:E2:E3}, \ttt{alias
 neutrino = n1:n2:n3:N1:N2:N3}, and \ttt{alias jet =
 u:d:s:c:U:D:S:C:g}, respectively.
 %%%%%
 \item
 \ttt{all} \newline
 \ttt{all} is a function that works on a logical expression and a list,
 \ttt{all {\em <log\_expr>} [{\em <list>}]}, and returns \ttt{true} if and only if
 \ttt{log\_expr} is fulfilled for {\em all} entries in \ttt{list}, and
 \ttt{false} otherwise. Examples: \ttt{all Pt > 100 GeV [lepton]}
 checks whether all leptons are harder than 100 GeV, \ttt{all Dist > 2
   [u:U, d:D]} checks whether all pairs of corresponding quarks
 are separated in $R$ space by more than 2. Logical expressions with
 \ttt{all} can be logically combined with \ttt{and} and
 \ttt{or}. (cf. also \ttt{any}, \ttt{and}, \ttt{no}, and \ttt{or})
 %%%%%
 \item
 \ttt{alt\_setup} \newline
 This command allows to specify alternative setups for a process/list
 of processes, \ttt{alt\_setup = \{ {\em <setup1>} \} [, \{ {\em <setup2>} \} ,
   ...]}. An alternative setup can be a resetting of a coupling
 constant, or different cuts etc. It can be particularly used in a
 ($\to$) \ttt{rescan} procedure.
 %%%%%
 \item
 \ttt{analysis} \newline
 This command, \ttt{analysis = {\em <log\_expr>}}, allows to define an
 analysis as a logical expression, with a syntax similar to the ($\to$)
 \ttt{cuts} or ($\to$) \ttt{selection} command. Note that a ($\to$)
 formally is a logical expression.
 %%%%%
 \item
 \ttt{and} \newline
 This is the standard two-place logical connective that has the value
 true if both of its operands are true, otherwise a value of false. It
 is applied to logical values, e.g. cut expressions. (cf. also
 \ttt{all}, \ttt{no}, \ttt{or}).
 %%%%%
 \item
 \ttt{any} \newline
 \ttt{any} is a function that works on a logical expression and a list,
 \ttt{any {\em <log\_expr>} [{\em <list>}]}, and returns \ttt{true} if
 \ttt{log\_expr} is fulfilled for any entry in \ttt{list}, and
 \ttt{false} otherwise. Examples: \ttt{any PDG == 13 [lepton]} checks
 whether any lepton is a muon, \ttt{any E > 2 * mW [jet]} checks
 whether any jet has an energy of twice the $W$ mass. Logical
 expressions with \ttt{any} can be logically combined with \ttt{and}
 and \ttt{or}. (cf. also \ttt{all}, \ttt{and}, \ttt{no}, and \ttt{or})
 %%%%%
 \item
 \ttt{as} \newline
 cf. \ttt{compile}
 %%%%%
 \item
 \ttt{ascii} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the standard \whizard\ verbose/debug ASCII event
 files. (cf. also \ttt{\$sample}, \ttt{\$sample\_normalization},
 \ttt{sample\_format})
 %%%%%
 \item
 \ttt{asin} \newline
 Numerical function \ttt{asin ({\em <num\_val>})} that calculates the
 arcsine trigonometric function (inverse of \ttt{sin}) of real and
 complex numerical numbers or variables. (cf. also \ttt{sin},
 \ttt{cos}, \ttt{tan}, \ttt{acos}, \ttt{atan})
 %%%%%
 \item
 \ttt{atan} \newline
 Numerical function \ttt{atan ({\em <num\_val>})} that calculates the
 arctangent trigonometric function (inverse of \ttt{tan}) of real and
 complex numerical numbers or variables. (cf. also \ttt{sin},
 \ttt{cos}, \ttt{tan}, \ttt{asin}, \ttt{acos})
 %%%%%
 \item
 \ttt{athena} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the ATHENA variant for HEPEVT ASCII event
 files. (cf. also \ttt{\$sample}, \ttt{\$sample\_normalization},
 \ttt{sample\_format})
 %%%%%
 \item
 \ttt{beam} \newline
 Constructor that specifies a particle (in a subevent) as beam particle. It is
 used in cuts, analyses or selections, e.g. \ttt{cuts = all Theta > 20
 degree [beam lepton, lepton]}. (cf. also \ttt{incoming}, \ttt{outgoing},
 \ttt{cuts}, \ttt{analysis}, \ttt{selection}, \ttt{record})
 %%%%%
 \item
 \ttt{beam\_events} \newline
 Beam structure specifier to read in lepton collider beamstrahlung's
 spectra from external files as pairs of energy fractions: \ttt{beams:
   e1, E1 => beam\_events}. Note that this is a pair spectrum that has to
 be applied to both beams simultaneously. (cf. also \ttt{beams},
 \ttt{\$beam\_events\_file}, \ttt{?beam\_events\_warn\_eof})
 %%%%%
 \item
 \ttt{beams} \newline
 This specifies the contents and structure of the beams: \ttt{beams =
   {\em <prt1>}, {\em <prt2>} [ => {\em <str\_fun1>} ....]}. If this
 command is absent in the input file, \whizard\ automatically takes the
 two incoming partons (or one for decays) of the corresponding process
 as beam particles, and no structure functions are applied. Protons and
 antiprotons as beam particles are predefined as \ttt{p} and
 \ttt{pbar}, respectively. A structure function, like \ttt{pdf\_builtin},
 \ttt{ISR}, \ttt{EPA} and so on are switched on as e.g. \ttt{beams = p,
 p => lhapdf}. Structure functions can be specified for one of the two
 beam particles only, of the structure function is not a
 spectrum. (cf. also \ttt{beams\_momentum}, \ttt{beams\_theta},
 \ttt{beams\_phi}, \ttt{beams\_pol\_density},
 \ttt{beams\_pol\_fraction}, \ttt{beam\_events}, \ttt{circe1},
 \ttt{circe2}, \ttt{energy\_scan}, \ttt{epa}, \ttt{ewa}, \ttt{isr},
 \ttt{lhapdf}, \ttt{pdf\_builtin}).
 %%%%%
 \item
 \ttt{beams\_momentum} \newline
 Command to set the momenta (or energies) for the two beams of a
 scattering process: \ttt{beams\_momentum = {\em <mom1>}, {\em <mom2>}} to allow
 for asymmetric beam setups (e.g. HERA: \ttt{beams\_momentum = 27.5
   GeV, 920 GeV}). Two arguments must be present
 for a scattering process, but the command can be used with one
 argument to integrate and simulate a decay of a moving
 particle. (cf. also \ttt{beams}, \ttt{beams\_theta},
 \ttt{beams\_phi}, \ttt{beams\_pol\_density},
 \ttt{beams\_pol\_fraction})
 %%%%%
 \item
 \ttt{beams\_phi} \newline
 Same as ($\to$) \ttt{beams\_theta}, but to allow for a non-vanishing
 beam azimuth angle, too. (cf. also \ttt{beams}, \ttt{beams\_theta},
 \ttt{beams\_momentum}, \ttt{beams\_pol\_density},
 \ttt{beams\_pol\_fraction})
 %%%%%
 \item
 \ttt{beams\_pol\_density} \newline
 This command allows to specify the initial state for polarized beams
 by the syntax: \ttt{beams\_pol\_density = @({\em <pol\_spec\_1>}),
   @({\em <pol\_spec\_2>})}. Two polarization specifiers are mandatory for
 scattering, while one can be used for decays from polarized
 probes. The specifier \ttt{{\em <pol\_spec\_i>}} can be empty (no
 polarization), has one entry (for a definite helicity/spin
 orientation), or ranges of entries of a spin density matrix. The
 command can be used globally, or as a local argument of the
 \ttt{integrate} command. For detailed information, see
 Sec.~\ref{sec:initialpolarization}. It is also possible to use
 variables as placeholders in the specifiers. Note that polarization is
 assumed to be complete, for partial polarization use ($\to$)
 \ttt{beams\_pol\_fraction}. (cf. also \ttt{beams}, \ttt{beams\_theta},
 \ttt{beams\_phi}, \ttt{beams\_momentum}, \ttt{beams\_pol\_fraction})
 %%%%%
 \item
 \ttt{beams\_pol\_fraction} \newline
 This command allows to specify the amount of polarization when using
 polarized beams ($\to$ \ttt{beams\_pol\_density}). The syntax is:
 \ttt{beams\_pol\_fraction = {\em <frac\_1>}, {\em <frac\_2>}}. Two fractions must
 be present for scatterings, being real numbers between \ttt{0} and
 \ttt{1}. A specification with percentage is also possible,
 e.g. \ttt{beams\_pol\_fraction = 80\%, 40\%}. (cf. also \ttt{beams},
 \ttt{beams\_theta}, \ttt{beams\_phi}, \ttt{beams\_momentum},
 \ttt{beams\_pol\_density})
 %%%%%
 \item
 \ttt{beams\_theta} \newline
 Command to set a crossing angle (with respect to the $z$ axis) for one
 or both of the beams of a
 scattering process: \ttt{beams\_theta = {\em <angle1>}, {\em <angle2>}} to allow
 for asymmetric beam setups (e.g. \ttt{beams\_angle = 0, 10
 degree}). Two arguments must be present for a scattering process, but
 the command can be used with one argument to integrate and simulate a
 decay of a moving particle. (cf. also \ttt{beams}, \ttt{beams\_phi},
 \ttt{beams\_momentum}, \ttt{beams\_pol\_density},
 \ttt{beams\_pol\_fraction})
 %%%%%
 \item
 \ttt{by} \newline
 Constructor that replaces the default sorting criterion (according to
 PDG codes) of the ($\to$) \ttt{sort} function on particle
 lists/subevents by one given by a unary or binary particle observable:
 \ttt{sort by {\em <observable>} [{\em <particles>} [, {\em
 <ref\_particles>}] ]}. (cf. also \ttt{sort}, \ttt{extract}, \ttt{join},
 \ttt{collect}, \ttt{combine}, \ttt{+})
 %%%%%
 \item
 \ttt{ceiling} \newline
 This is a function \ttt{ceiling ({\em <num\_val>})} that gives the
 least integer greater than or equal to \ttt{{\em <num\_val>}},
 e.g. \ttt{int i = ceiling (4.56789)} gives \ttt{i = 5}. (cf. also
 \ttt{int}, \ttt{nint}, \ttt{floor})
 %%%%%
 \item
 \ttt{circe1} \newline
 Beam structure specifier for the \circeone\ structure function for
 beamstrahlung at a linear lepton collider: \ttt{beams = e1, E1 =>
 circe1}. Note that this is a pair spectrum, so the specifier acts for
 both beams simultaneously. (cf. also \ttt{beams}, \ttt{?circe1\_photons},
 \ttt{?circe1\_photon2}, \ttt{circe1\_sqrts},
 \ttt{?circe1\_generate}, \ttt{?circe1\_map},
 \ttt{circe1\_eps}, \newline \ttt{circe1\_mapping\_slope}, \ttt{circe1\_ver},
 \ttt{circe1\_rev}, \ttt{\$circe1\_acc}, \ttt{circe1\_chat})
 %%%%%
 \item
 \ttt{circe2} \newline
 Beam structure specifier for the lepton-collider structure function
 for photon spectra, \circetwo: \ttt{beams = A, A => circe2}. Note that
 this is a pair spectrum, an application to only one beam is not
 possible. (cf. also \ttt{beams}, \ttt{?circe2\_polarized},
 \ttt{\$circe2\_file}, \ttt{\$circe2\_design})
 %%%%%
 \item
 \ttt{clear} \newline
 This command allows to clear a variable set before: \ttt{clear
 ({\em <clearable var.>})} resets the variable \ttt{{\em <clearable var.>}} which
 could be the \ttt{beams}, the \ttt{unstable} settings, \ttt{sqrts},
 any kind of \ttt{cuts} or \ttt{scale} expressions, any user-set
 variable etc. The syntax of the command is completely analogous to
 ($\to$) \ttt{show}.
 %%%%%
 \item
 \ttt{close\_out} \newline
 With the command, \ttt{close\_out ("{\em <out\_file">})} user-defined
 information like data or ($\to$) \ttt{printf} statements can be
 written out to a user-defined file. The command closes an I/O stream to
 an external file \ttt{{\em <out\_file>}}. (cf. also \ttt{open\_out},
 \ttt{\$out\_file}, \ttt{printf})
 %%%%%
 \item
 \ttt{cluster} \newline
 Command that allows to cluster all particles in a subevent to a set of
 jets: \ttt{cluster [{\em<particles>}]}. It also to cluster particles
 subject to a certain boolean condition, \ttt{cluster if
   {\em<condition>} [{\em<particles>}]}. At the moment only available
 if the \fastjet\ package is linked.
 (cf. also \ttt{jet\_r}, \ttt{combine}, \ttt{jet\_algorithm},
 \ttt{kt\_algorithm}, \newline \ttt{cambridge\_[for\_passive\_]algorithm},
 \ttt{antikt\_algorithm}, \ttt{plugin\_algorithm}, \newline
 \ttt{genkt\_[for\_passive\_]algorithm},
 \ttt{ee\_kt\_algorithm}, \ttt{ee\_genkt\_algorithm},
 \ttt{?keep\_flavors\_when\_clustering})
 %%%%%
 \item
 \ttt{collect} \newline
 The \ttt{collect [{\em <list>}]} operation collects all particles in
 the list \ttt{{\em <list>}} into a one-entry subevent with a
 four-momentum of the sum of all four-momenta of non-overlapping
 particles in \ttt{{\em <list>}}. (cf. also \ttt{combine},
 \ttt{select}, \ttt{extract}, \ttt{sort})
 %%%%%
 \item
 \ttt{complex} \newline
 Defines a complex variable. The syntax is e.g. \ttt{complex x = 2 + 3
   * I}. (cf.~also \ttt{int}, \ttt{real})
 %%%%%
 \item
 \ttt{combine} \newline
 The \ttt{combine [{\em <list1>}, {\em <list2>}]} operation makes a particle list
 whose entries are the result of adding (the momenta of) each pair of
 particles in the two input lists \ttt{list1}, {list2}. For example,
 \ttt{combine [incoming lepton, lepton]} constructs all mutual pairings
 of an incoming lepton with an outgoing lepton (an alias for the
 leptons has to be defined, of course). (cf. also \ttt{collect},
 \ttt{select}, \ttt{extract}, \ttt{sort}, \ttt{+})
 %%%%%
 \item
 \ttt{compile} \newline
 The \ttt{compile ()} command has no arguments (the parentheses can
 also been left out: /\ttt{compile ()}. The command is optional, it
 invokes the compilation of the process(es) (i.e. the matrix element
 file(s)) to be compiled as a shared library. This shared object file
 has the standard name \ttt{default\_lib.so} and resides in the
 \ttt{.libs} subdirectory of the corresponding user workspace. If the
 user has defined a different library name \ttt{lib\_name} with the
 \ttt{library} command, then WHIZARD compiles this as the shared object
 \ttt{.libs/lib\_name.so}. (This allows to split process classes and to
 avoid too large libraries.)
 Another possibility is to use the command \ttt{compile as
   "static\_name"}. This will compile and link the process library in a
 static way and create the static executable \ttt{static\_name} in the
 user workspace. (cf. also \ttt{library})
 %%%%%
 \item
 \ttt{compile\_analysis} \newline
 The \ttt{compile\_analysis} statement does the same as
 the \ttt{write\_analysis} command, namely to tell \whizard\ to write
 the analysis setup by the user for the \sindarin\ input file under
 consideration. If no \ttt{\$out\_file} is provided, the histogram
 tables/plot data etc. are written to the default file
 \ttt{whizard\_analysis.dat}. In addition to \ttt{write\_analysis},
 \ttt{compile\_analysis} also invokes the \whizard\ \LaTeX routines for
 producing postscript or PDF output of the data (unless the flag
 $\rightarrow$ \ttt{?analysis\_file\_only} is set to \ttt{true}).
 (cf. also \ttt{\$out\_file}, \ttt{write\_analysis},
 \ttt{?analysis\_file\_only})
 %%%%%
 \item
 \ttt{conjg} \newline
 Numerical function that takes the complex conjugate of its argument:
 \ttt{conjg ({\em <num\_val>})} yields \ttt{{\em
 <num\_val>}$^\ast$}. (cf. also \ttt{abs}, \ttt{sgn}, \ttt{mod}, \ttt{modulo})
 %%%%%
 \item
 \ttt{cos} \newline
 Numerical function \ttt{cos ({\em <num\_val>})} that calculates the
 cosine trigonometric function of real and complex numerical numbers or
 variables. (cf. also \ttt{sin}, \ttt{tan}, \ttt{asin}, \ttt{acos},
 \ttt{atan})
 %%%%%
 \item
 \ttt{cosh} \newline
 Numerical function \ttt{cosh ({\em <num\_val>})} that calculates the
 hyperbolic cosine function of real and complex numerical numbers or
 variables. Note that its inverse function is part of the
 \ttt{Fortran2008} status and hence not realized. (cf. also \ttt{sinh},
 \ttt{tanh})
 %%%%%
 \item
 \ttt{count} \newline
 Subevent function that counts the number of particles or particle
 pairs in a subevent: \ttt{count [{\em <particles\_1>} [, {\em
 <particles\_2>}]]}. This can also be a counting subject to a
 condition: \ttt{count if {\em <condition>} [{\em <particles\_1>} [,
 {\em <particles\_2>}]]}.
 %%%%%
 \item
 \ttt{cuts} \newline
 This command defines the cuts to be applied to certain processes. The
 syntax is: \ttt{cuts = {\em <log\_class>} {\em <log\_expr>} [{\em <unary or binary
   particle (list) arg>}]}, where the cut expression must be initialized
 with a logical classifier \ttt{log\_class} like \ttt{all}, \ttt{any},
 \ttt{no}. The logical expression \ttt{log\_expr} contains the cut to
 be evaluated. Note that this need not only be a kinematical cut
 expression like \ttt{E > 10  GeV} or \ttt{5 degree < Theta < 175 degree},
 but can also be some sort of trigger expression or event selection.
 Whether the expression is evaluated on particles or pairs
 of particles depends on whether the discriminating variable is unary or
 binary, \ttt{Dist} being obviously binary, \ttt{Pt} being unary. Note that
 some variables are both unary and binary, e.g. the invariant mass $M$. Cut
 expressions can be connected by the logical  connectives \ttt{and} and
 \ttt{or}. The \ttt{cuts} statement acts on all subsequent process
 integrations and analyses until a new \ttt{cuts} statement appears.
 (cf. also \ttt{all}, \ttt{any},
 \ttt{Dist}, \ttt{E}, \ttt{M},
 \ttt{no}, \ttt{Pt}).
 %%%%%
 \item
 \ttt{debug} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the very verbose \whizard\ ASCII event
 file format intended for debugging. (cf. also \ttt{\$sample},
 \ttt{sample\_format}, \ttt{\$sample\_normalization})
 %%%%%
 \item
 \ttt{degree} \newline
 Expression specifying the physical unit of degree for angular
 variables, e.g. the cut expression function \ttt{Theta}. (if no unit is
 specified for angular variables, radians are used; cf. \ttt{rad}, \ttt{mrad}).
 %%%%
 \item
 \ttt{Dist} \newline
 Binary observable specifier, that gives the $\eta$-$\phi$-
 (pseudorapidity-azimuth) distance $R = \sqrt{(\Delta \eta)^2 +
 (\Delta\phi)^2}$ between the momenta of the two particles: \ttt{eval
 Dist [jet, jet]}. (cf. also \ttt{eval}, \ttt{cuts}, \ttt{selection},
 \ttt{Theta}, \ttt{Eta}, \ttt{Phi})
 %%%%%
 \item
 \ttt{dump} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the intrinsic \whizard\ event record format
 (output of the \ttt{particle\_t} type container). (cf. also
 \ttt{\$sample}, \ttt{sample\_format}, \ttt{\$sample\_normalization}
 %%%%%
 \item
 \ttt{E} \newline
 Unary (binary) observable specifier for the energy of a single
 (two) particle(s), e.g. \ttt{eval E ["W+"]}, \ttt{all E > 200 GeV [b,
   B]}. (cf. \ttt{eval}, \ttt{cuts}, \ttt{selection})
 %%%%%
 \item
 \ttt{else} \label{sindarin_else}\newline
 Constructor for providing an alternative in a conditional clause:
 \ttt{if {\em <log\_expr>} then {\em <expr 1>} else {\em <expr 2>} endif}. (cf. also
 \ttt{if}, \ttt{elsif}, \ttt{endif}, \ttt{then}).
 %%%%%
 \item
 \ttt{elsif} \newline
 Constructor for concatenating more than one conditional clause with
 each other: \ttt{if {\em <log\_expr 1>} then {\em <expr 1>} elsif {\em <log\_expr 2>}
 then {\em <expr 2>} \ldots endif}. (cf. also \ttt{if}, \ttt{else},
 \ttt{endif}, \ttt{then}).
 %%%%%
 \item
 \ttt{endif} \newline
 Mandatory constructor to conclude a conditional clause: \ttt{if
   {\em <log\_expr>} then \ldots endif}. (cf. also \ttt{if},
 \ttt{else}, \ttt{elsif}, \ttt{then}).
 %%%%%
 \item
 \ttt{energy\_scan} \newline
 Beam structure specifier for the energy scan structure function:
 \ttt{beams = e1, E1 => energy\_scan}. This pair spectrum that has to
 be applied to both beams simultaneously can be used to scan over a
 range of collider energies without using the \ttt{scan} command.
 (cf. also \ttt{beams}, \ttt{scan}, \ttt{?energy\_scan\_normalize})
 %%%%%
 \item
 \ttt{epa} \newline
 Beam structure specifier for the equivalent-photon approximation
 (EPA), i.e the Weizs\"acker-Williams structure function:
 e.g. \ttt{beams = e1, E1 => epa} (applied to both beams), or
 e.g. \ttt{beams = e1, u => epa, none} (applied to only one
 beam). (cf. also \ttt{beams}, \ttt{epa\_alpha}, \ttt{epa\_x\_min},
 \ttt{epa\_mass}, \ttt{epa\_q\_max}, \ttt{epa\_q\_min},
 \ttt{?epa\_recoil}, \ttt{?epa\_keep\_energy})
 %%%%%
 \item
 \ttt{Eta} \newline
 Unary and also binary observable specifier, that as a unary observable
 gives the pseudorapidity of a particle momentum. The pseudorapidity is
 given by $\eta = - \log \left[ \tan (\theta/2) \right]$, where
 $\theta$ is the angle with the beam direction. As a binary
 observable, it gives the pseudorapidity difference between the momenta
 of two particles, where $\theta$ is the enclosed angle: \ttt{eval Eta
 [e1]},  \ttt{all abs (Eta) < 3.5 [jet, jet]}. (cf. also \ttt{eval},
 \ttt{cuts}, \ttt{selection}, \ttt{Rap}, \ttt{abs})
 %%%%%
 \item
 \ttt{eV} \newline
 Physical unit, stating that the corresponding number is in electron
 volt. (cf. also \ttt{keV}, \ttt{meV}, \ttt{MeV}, \ttt{GeV}, \ttt{TeV})
 %%%%%
 \item
 \ttt{eval} \newline
 Evaluator that tells \whizard\ to evaluate the following expr:
 \ttt{eval {\em <expr>}}. Examples are: \ttt{eval Rap [e1]}, \ttt{eval
   M / 1 GeV [combine [q,Q]]} etc. (cf. also \ttt{cuts},
 \ttt{selection}, \ttt{record})
 %%%%%
 \item
 \ttt{ewa} \newline
 Beam structure specifier for the equivalent-photon approximation
 (EWA): e.g. \ttt{beams = e1, E1 => ewa} (applied to both beams), or
 e.g. \ttt{beams = e1, u => ewa, none} (applied to only one
 beam). (cf. also \ttt{beams}, \ttt{ewa\_x\_min}, \ttt{ewa\_pt\_max},
 \ttt{ewa\_mass}, \ttt{?ewa\_keep\_energy},
 \ttt{?ewa\_recoil})
 %%%%%
 \item
 \ttt{exec} \newline
 Constructor \ttt{exec ("{\em <cmd\_name>}")} that demands WHIZARD to
 execute/run the command \ttt{cmd\_name}. For this to work that
 specific command must be present either in the path of the operating
 system or as a command in the user workspace.
 %%%%%
 \item
 \ttt{exit} \newline
 Command to finish the \whizard\ run (and not execute any further code
 beyond the appearance of \ttt{exit} in the \sindarin\ file. The command
 (which is the same as $\to$ \ttt{quit}) allows for an argument,
 \ttt{exit ({\em <expr>})}, where the expression can be executed, e.g. a
 screen message or an exit code.
 %%%%%
 \item
 \ttt{exp} \newline
 Numerical function \ttt{exp ({\em <num\_val>})} that calculates the
 exponential of real and complex numerical numbers or
 variables. (cf. also \ttt{sqrt}, \ttt{log}, \ttt{log10})
 %%%%%
 \item
 \ttt{expect} \newline
 The binary function \ttt{expect} compares two numerical expressions
 whether they fulfill a certain ordering condition or are equal up
 to a specific uncertainty or tolerance which can bet set by the
 specifier \ttt{tolerance}, i.e. in principle it checks whether a
 logical expression is true. The \ttt{expect} function does actually
 not just check a value for correctness, but also records its result.
 If failures are present when the program terminates, the exit code is
 nonzero. The syntax is  \ttt{expect ({\em <num1>} {\em
 <log\_comp>} {\em <num2>})}, where \ttt{{\em <num1>}} and
 \ttt{{\em <num2>}} are two numerical values (or
 corresponding variables) and  \ttt{{\em <log\_comp>}} is one of the following
 logical comparators: \ttt{<}, \ttt{>}, \ttt{<=},  \ttt{>=}, \ttt{==},
 \ttt{<>}.
 (cf. also \ttt{<}, \ttt{>}, \ttt{<=},  \ttt{>=}, \ttt{==}, \ttt{<>},
 \ttt{tolerance}).
 %%%%%
 \item
 \ttt{extract} \newline
 Subevent function that either extracts the first element of a
 particle list/subevent: \ttt{extract [ {\em <particles>}]}, or the
 element at position \ttt{<index\_value>} of the particle list:
 \ttt{extract {\em index <index\_value>} [ {\em
     <particles>}]}. Negative index values count from the end of the
 list. (cf. also \ttt{sort}, \ttt{combine},
 \ttt{collect}, \ttt{+}, \ttt{index})
 %%%%%
 \item
 \ttt{factorization\_scale} \newline
 This is a command, \ttt{factorization\_scale = {\em <expr>}}, that sets
 the factorization scale of a process or list of processes. It
 overwrites a possible scale set by the ($\to$) \ttt{scale} command.
 \ttt{{\em <expr>}} can be any kinematic expression that leads to a result of
 momentum dimension one, e.g. \ttt{100 GeV}, \ttt{eval
 Pt [e1]}. (cf. also \ttt{renormalization\_scale}).
 %%%%%
 \item
 \ttt{false} \newline
 Constructor stating that a logical expression or variable is false,
 e.g. \ttt{?{\em <log\_var>} = false}. (cf. also \ttt{true}).
 %%%%%
 \item
 \ttt{fbarn} \newline
 Physical unit, stating that a number is in femtobarns ($10^{-15}$
 barn). (cf. also \ttt{nbarn}, \ttt{abarn}, \ttt{pbarn})
 %%%%%
 \item
 \ttt{floor} \newline
 This is a function \ttt{floor ({\em <num\_val>})} that gives the
 greatest integer less than or equal to \ttt{{\em <num\_val>}},
 e.g. \ttt{int i = floor (4.56789)} gives \ttt{i = 4}. (cf. also
 \ttt{int}, \ttt{nint}, \ttt{ceiling})
 %%%%%
 \item
 \ttt{gaussian} \newline
 Beam structure specifier that imposes a Gaussian energy distribution,
 separately for each beam.  The $\sigma$ values are set by
 \ttt{gaussian\_spread1} and \ttt{gaussian\_spread2}, respectively.
 %%%%%
 \item
 \ttt{GeV} \newline
 Physical unit, energies in $10^9$ electron volt. This is the default
 energy unit of WHIZARD. (cf. also \ttt{eV}, \ttt{keV}, \ttt{MeV}, \ttt{meV},
 \ttt{TeV})
 %%%%%
 \item
 \ttt{graph} \newline
 This command defines the necessary information regarding producing
 a graph of a function in \whizard's internal graphical \gamelan\
 output. The syntax is: \ttt{graph {\em <record\_name>} \{ {\em <optional
 arguments>} \}}. The record with name \ttt{{\em <record\_name>}} has to be
 defined, either before or after the graph definition. Possible optional
 arguments of the \ttt{graph} command are the minimal and maximal values
 of the axes (\ttt{x\_min}, \ttt{x\_max}, \ttt{y\_min}, \ttt{y\_max}).
 (cf. \ttt{plot}, \ttt{histogram}, \ttt{record})
 %%%%%
 \item
 \ttt{Hel} \newline
 Unary observable specifier that allows to specify the helicity of a
 particle, e.g. \ttt{all Hel == -1 [e1]} in a selection. (cf. also
 \ttt{eval}, \ttt{cuts}, \ttt{selection})
 %%%%%
 \item
 \ttt{hepevt} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of HEPEVT ASCII event files. (cf. also \ttt{\$sample},
 \ttt{sample\_format})
 %%%%%
 \item
 \ttt{hepevt\_verb} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the extended or verbose version of HEPEVT ASCII event
 files. (cf. also \ttt{\$sample}, \ttt{sample\_format})
 %%%%%
 \item
 \ttt{hepmc} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of HepMC ASCII event files. Note that this is only
 available if the HepMC package is installed and correctly
 linked. (cf. also \ttt{\$sample}, \ttt{sample\_format},
 \ttt{?hepmc\_output\_cross\_section})
 %%%%%
 \item
 \ttt{histogram} \newline
 This command defines the necessary information regarding plotting data
 as a histogram, in the form of: \ttt{histogram {\em <record\_name>} \{
 {\em <optional arguments>} \}}. The record with name \ttt{{\em <record\_name>}} has to be
 defined, either before or after the histogram definition. Possible optional
 arguments of the \ttt{histogram} command are the minimal and maximal values
 of the axes (\ttt{x\_min}, \ttt{x\_max}, \ttt{y\_min}, \ttt{y\_max}).
 (cf. \ttt{graph}, \ttt{plot}, \ttt{record})
 %%%%%
 \item
 \ttt{if} \newline
 Conditional clause with the construction \ttt{if {\em <log\_expr>} then
 {\em <expr>} [else {\em <expr>} \ldots] endif}. Note that there must be an
 \ttt{endif}  statement. For more complicated expressions it is better
 to use expressions in parentheses: \ttt{if ({\em <log\_expr>}) then
 \{{\em <expr>}\} else \{{\em <expr>}\} endif}. Examples are a selection of up quarks
 over down quarks depending on a logical variable: \ttt{if ?ok then u
   else d}, or the setting of an integer variable depending on the
 rapidity of some particle: \ttt{if (eta > 0) then \{ a = +1\} else
 \{ a = -1\}}. (cf. also \ttt{elsif}, \ttt{endif}, \ttt{then})
 %%%%%
 \item
 \ttt{in} \newline
 Second part of the constructor to let a variable be local to an
 expression. It has the syntax \ttt{let {\em <var>} = {\em <value>} in
 {\em <expression>}}.  E.g. \ttt{let int a = 3 in let int b = 4 in
 {\em <expression>}} (cf. also \ttt{let})
 %%%%%
 \item
 \ttt{include} \newline
 The \ttt{include} statement, \ttt{include ("file.sin")} allows to
 include external \sindarin\ files \ttt{file.sin} into the main WHIZARD
 input file. A standard example is the inclusion of the standard cut
 file \ttt{default\_cuts.sin}.
 %%%%%
 \item
 \ttt{incoming} \newline
 Constructor that specifies particles (or subevents) as incoming. It is
 used in cuts, analyses or selections, e.g. \ttt{cuts = all Theta > 20
 degree [incoming lepton, lepton]}. (cf. also \ttt{beam}, \ttt{outgoing},
 \ttt{cuts}, \ttt{analysis}, \ttt{selection}, \ttt{record})
 %%%%%
 \item
 \ttt{index} \newline
 Specifies the position of the element of a particle to be extracted by
 the subevent function ($\to$) \ttt{extract}: \ttt{extract {\em index
 <index\_value>} [ {\em <particles>}]}. Negative index values count
 from the end of the list. (cf. also \ttt{extract}, \ttt{sort}, \ttt{combine},
 \ttt{collect}, \ttt{+})
 %%%%%
 \item
 \ttt{int} \newline
 1) This is a constructor to specify integer constants in the input
 file. Strictly speaking, it is a unary function setting the value
 \ttt{int\_val} of the integer variable \ttt{int\_var}:
 \ttt{int {\em <int\_var>} = {\em <int\_val>}}. Note that is mandatory for all
 user-defined variables. (cf. also \ttt{real} and \ttt{complex})
 2) It is a function \ttt{int ({\em <num\_val>})} that converts real and
 complex numbers (here their real parts) into integers. (cf. also
 \ttt{nint}, \ttt{floor}, \ttt{ceiling})
 %%%%%
 \item
 \ttt{integrate} \newline
 The \ttt{integrate ({\em <proc\_name>}) \{ {\em <integrate\_options>} \}} command
 invokes the integration (phase-space generation and Monte-Carlo
 sampling) of the process \ttt{proc\_name} (which can also be a list of
 processes) with the integration options
 \ttt{{\em <integrate\_options>}}. Possible options are (1) via
 \ttt{\$integration\_method = "{\em <intg. method>}"} the integration
 method (the default being VAMP), (2) the number of iterations and
 calls per integration during the Monte-Carlo phase-space integration
 via the \ttt{iterations} specifier; (3) goal for the
 accuracy, error or relative error (\ttt{accuracy\_goal},
 \ttt{error\_goal}, \ttt{relative\_error\_goal}). (4) Invoking only
 phase space generation (\ttt{?phs\_only = true}), (5) making test
 calls of the matrix element. (cf. also \ttt{iterations},
 \ttt{accuracy\_goal}, \ttt{error\_goal}, \ttt{relative\_error\_goal},
 \ttt{error\_threshold})
 %%%%%
 \item
 \ttt{isr} \newline
 Beam structure specifier for the lepton-collider/QED initial-state
 radiation (ISR) structure function: e.g. \ttt{beams = e1, E1 => isr}
 (applied to both beams), or e.g. \ttt{beams = e1, u => isr, none}
 (applied to only one beam). (cf. also \ttt{beams}, \ttt{isr\_alpha},
 \ttt{isr\_q\_max}, \ttt{isr\_mass}, \ttt{isr\_order},
 \ttt{?isr\_recoil}, \ttt{?isr\_keep\_energy})
 %%%%%
 \item
 \ttt{iterations} \qquad (default: internal heuristics) \newline
 Option to set the number of iterations and calls per iteration during
 the Monte-Carlo phase-space integration process. The syntax is
 \ttt{iterations = {\em <n\_iterations>}:{\em <n\_calls>}}. Note that this can be
 also a list, separated by colons, which breaks up the integration
 process into passes of the specified number of integrations and calls
 each. It works for all integration methods. For VAMP, there is the
 additional option to specify whether grids and channel weights should
 be adapted during iterations (\ttt{"g"}, \ttt{"w"},
 \ttt{"gw"} for both, or \ttt{""} for no adaptation).   (cf. also
 \ttt{integrate}, \ttt{accuracy\_goal}, \ttt{error\_goal},
 \ttt{relative\_error\_goal}, \ttt{error\_threshold}).
 %%%%%
 \item
 \ttt{join} \newline
 Subevent function that concatenates two particle lists/subevents if
 there is no overlap: \ttt{join [{\em <particles>}, {\em
 <new\_particles>}]}. The joining of the two lists can also be made
 depending on a condition: \ttt{join if {\em <condition>} [{\em
 <particles>}, {\em <new\_particles>}]}. (cf. also \ttt{\&},
 \ttt{collect}, \ttt{combine}, \ttt{extract}, \ttt{sort}, \ttt{+})
 %%%%%
 \item
 \ttt{keV} \newline
 Physical unit, energies in $10^3$ electron volt. (cf. also \ttt{eV},
 \ttt{meV}, \ttt{MeV}, \ttt{GeV}, \ttt{TeV})
 %%%%%
 \item
 \ttt{kT} \newline
 Binary particle observable that represents a jet $k_T$ clustering
 measure: \ttt{kT [j1, j2]} gives the following kinematic expression:
 $2 \min(E_{j1}^2, E_{j2}^2) / Q^2 \times (1 - \cos\theta_{j1,j2})$. At the
 moment, $Q^2 = 1$.
 %%%%%
 \item
 \ttt{let} \newline
 This allows to let a variable be local to an expression. It has the
 syntax \ttt{let {\em <var>} = {\em <value>} in {\em <expression>}}.
 E.g. \ttt{let int a = 3 in let int b = 4 in {\em <expression>}}
 (cf. also \ttt{in})
 %%%%%
 \item
 \ttt{lha} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the \whizard\ version 1 style (deprecated) LHA ASCII event
 format files. (cf. also \ttt{\$sample}, \newline
 \ttt{sample\_format})
 %%%%%
 \item
 \ttt{lhapdf} \newline
 This is a beams specifier to demand calling \lhapdf\ parton densities as
 structure functions to integrate processes in hadron collisions. Note
 that this only works if the external \lhapdf\ library is present and
 correctly linked. (cf. \ttt{beams}, \ttt{\$lhapdf\_dir},
 \ttt{\$lhapdf\_file}, \ttt{lhapdf\_photon},
 \ttt{\$lhapdf\_photon\_file}, \ttt{lhapdf\_member},
 \ttt{lhapdf\_photon\_scheme})
 %%%%%
 \item
 \ttt{lhapdf\_photon} \newline
 This is a beams specifier to demand calling \lhapdf\ parton densities as
 structure functions to integrate processes in hadron collisions with a
 photon as initializer of the hard scattering process. Note
 that this only works if the external \lhapdf\ library is present and
 correctly linked. (cf. \ttt{beams}, \ttt{lhapdf}, \ttt{\$lhapdf\_dir},
 \ttt{\$lhapdf\_file}, \ttt{\$lhapdf\_photon\_file},
 \ttt{lhapdf\_member}, \ttt{lhapdf\_photon\_scheme})
 %%%%%
 \item
 \ttt{lhef} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the Les Houches Accord (LHEF) event format files, with
 XML headers. There are several different versions of this format,
 which can be selected via the \ttt{\$lhef\_version} specifier
 (cf. also \ttt{\$sample}, \ttt{sample\_format}, \ttt{\$lhef\_version},
 \ttt{\$lhef\_extension}, \ttt{?lhef\_write\_sqme\_prc},
 \newline \ttt{?lhef\_write\_sqme\_ref}, \ttt{?lhef\_write\_sqme\_alt})
 %%%%%
 \item
 \ttt{library} \newline
 The command \ttt{library = "{\em <lib\_name>}"} allows to specify a separate
 shared object library archive \ttt{lib\_name.so}, not using the
 standard library \ttt{default\_lib.so}. Those libraries (when using
 shared libraries) are located in the \ttt{.libs} subdirectory of the
 user workspace. Specifying a separate library is useful for splitting
 up large lists of processes, or to restrict a larger number of
 different loaded model files to one specific process library.
 (cf. also \ttt{compile}, \ttt{\$library\_name})
 %%%%%
 \item
 \ttt{log} \newline
 Numerical function \ttt{log ({\em <num\_val>})} that calculates the
 natural logarithm of real and complex numerical numbers or
 variables. (cf. also \ttt{sqrt}, \ttt{exp}, \ttt{log10})
 %%%%%
 \item
 \ttt{log10} \newline
 Numerical function \ttt{log10 ({\em <num\_val>})} that calculates the
 base 10 logarithm of real and complex numerical numbers or
 variables. (cf. also \ttt{sqrt}, \ttt{exp}, \ttt{log})
 %%%%%
 \item
 \ttt{long} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the long variant of HEPEVT ASCII event
 files. (cf. also \ttt{\$sample},
 \ttt{sample\_format})
 %%%%%
 \item
 \ttt{M} \newline
 Unary (binary) observable specifier for the (signed) mass of a single
 (two) particle(s), e.g. \ttt{eval M [e1]}, \ttt{any M = 91 GeV [e2,
   E2]}. (cf. \ttt{eval}, \ttt{cuts}, \ttt{selection})
 %%%%%
 \item
 \ttt{M2} \newline
 Unary (binary) observable specifier for the mass squared of a single
 (two) particle(s), e.g. \ttt{eval M2 [e1]}, \ttt{all M2 > 2*mZ [e2,
   E2]}. (cf. \ttt{eval}, \ttt{cuts}, \ttt{selection})
 %%%%%
 \item
 \ttt{max} \newline
 Numerical function with two arguments \ttt{max ({\em <var1>}, {\em
 <var2>})} that gives the maximum of the two arguments: $\max (var1,
 var2)$. It can act on all combinations of integer and real
 variables. Example: \ttt{real heavier\_mass = max (mZ, mH)}. (cf. also
 \ttt{min})
 %%%%%
 \item
 \ttt{meV} \newline
 Physical unit, stating that the corresponding number is in $10^{-3}$
 electron volt. (cf. also \ttt{eV}, \ttt{keV}, \ttt{MeV}, \ttt{GeV},
 \ttt{TeV})
 %%%%%
 \item
 \ttt{MeV} \newline
 Physical unit, energies in $10^6$ electron volt. (cf. also \ttt{eV},
 \ttt{keV}, \ttt{meV}, \ttt{GeV}, \ttt{TeV})
 %%%%%
 \item
 \ttt{min} \newline
 Numerical function with two arguments \ttt{min ({\em <var1>}, {\em
 <var2>})} that gives the minimum of the two arguments: $\min (var1,
 var2)$. It can act on all combinations of integer and real
 variables. Example: \ttt{real lighter\_mass = min (mZ, mH)}. (cf. also
 \ttt{max})
 %%%%%
 \item
 \ttt{mod} \newline
 Numerical function for integer and real numbers \ttt{mod (x, y)} that
 computes the remainder of the division of \ttt{x} by \ttt{y} (which
 must not be zero). (cf. also
 \ttt{abs}, \ttt{conjg}, \ttt{sgn}, \ttt{modulo})
 %%%%%
 \item
 \ttt{model} \qquad (default: \ttt{SM}) \newline
 With this specifier, \ttt{model = {\em <model\_name>}}, one sets the hard
 interaction physics model for the processes defined after this model
 specification. The list of available models can be found in Table
 \ref{tab:models}. Note that the model specification can appear
 arbitrarily often in a \sindarin\ input file, e.g. for compiling and
 running processes defined in different physics models. (cf. also
 \ttt{\$model\_name})
 %%%%%
 \item
 \ttt{modulo} \newline
 Numerical function for integer and real numbers \ttt{modulo (x, y)} that
 computes the value of $x$ modulo $y$. (cf. also
 \ttt{abs}, \ttt{conjg}, \ttt{sgn}, \ttt{mod})
 %%%%%
 \item
 \ttt{mokka} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the MOKKA variant for HEPEVT ASCII event
 files. (cf. also \ttt{\$sample},
 \ttt{sample\_format})
 %%%%%
 \item
 \ttt{mrad} \newline
 Expression specifying the physical unit of milliradians for angular
 variables. This default in \whizard\ is \ttt{rad}. (cf. \ttt{degree}, \ttt{rad}).
 %%%%%
 \item
 \ttt{nbarn} \newline
 Physical unit, stating that a number is in nanobarns ($10^{-9}$
 barn). (cf. also \ttt{abarn}, \ttt{fbarn}, \ttt{pbarn})
 %%%%%
 \item
 \ttt{n\_in} \newline
 Integer variable that accesses the number of incoming particles of a
 process. It can be used in cuts or in an analysis. (cf. also
 \ttt{sqrts\_hat}, \ttt{cuts}, \ttt{record}, \ttt{n\_out}, \ttt{n\_tot})
 %%%%%
 \item
 \ttt{Nacl} \newline
 Unary observable specifier that returns the total number of open anticolor lines
 of a particle or subevent (i.e., composite particle).  Defined only if
 \ttt{?colorize\_subevt} is true.. (cf. also
 \ttt{Ncol}, \ttt{?colorize\_subevt})
 %%%%%
 \item
 \ttt{Ncol} \newline
 Unary observable specifier that returns the total number of open color lines
 of a particle or subevent (i.e., composite particle).  Defined only if
 \ttt{?colorize\_subevt} is true.. (cf. also
 \ttt{Nacl}, \ttt{?colorize\_subevt})
 %%%%%
 \item
 \ttt{nint} \newline
 This is a function \ttt{nint ({\em <num\_val>})} that converts real
 numbers into the closest integer, e.g. \ttt{int i = nint (4.56789)}
 gives \ttt{i = 5}. (cf. also
 \ttt{int}, \ttt{floor}, \ttt{ceiling})
 %%%%%
 \item
 \ttt{no} \newline
 \ttt{no} is a function that works on a logical expression and a list,
 \ttt{no {\em <log\_expr>} [{\em <list>}]}, and returns \ttt{true} if and only if
 \ttt{log\_expr} is fulfilled for {\em none} of the entries in
 \ttt{list}, and \ttt{false} otherwise. Examples: \ttt{no Pt < 100 GeV
   [lepton]} checks whether no lepton is softer than 100 GeV. It is the
 logical opposite of the function \ttt{all}. Logical expressions with
 \ttt{no} can be logically combined with \ttt{and} and
 \ttt{or}. (cf. also \ttt{all}, \ttt{any}, \ttt{and}, and \ttt{or})
 %%%%%
 \item
 \ttt{none} \newline
 Beams specifier that can used to explicitly {\em not} apply a
 structure function to a beam, e.g. in HERA physics: \ttt{beams = e1, P
   => none, pdf\_builtin}. (cf. also \ttt{beams})
 %%%%%
 \item
 \ttt{not} \newline
 This is the standard logical negation that converts true into false
 and vice versa. It is applied to logical values, e.g. cut
 expressions. (cf. also \ttt{and}, \ttt{or}).
 %%%%%
 \item
 \ttt{n\_out} \newline
 Integer variable that accesses the number of outgoing particles of a
 process. It can be used in cuts or in an analysis. (cf. also
 \ttt{sqrts\_hat}, \ttt{cuts}, \ttt{record}, \ttt{n\_in}, \ttt{n\_tot})
 %%%%%
 \item
 \ttt{n\_tot} \newline
 Integer variable that accesses the total number of particles (incoming
 plus outgoing) of a process. It can be used in cuts or in an
 analysis. (cf. also \ttt{sqrts\_hat}, \ttt{cuts}, \ttt{record},
 \ttt{n\_in}, \ttt{n\_out})
 %%%%%
 \item
 \ttt{observable} \newline
 With this, \ttt{observable = {\em <obs\_spec>}}, the user is able to define
 a variable specifier \ttt{obs\_spec} for observables. These can be
 reused in the analysis, e.g. as a \ttt{record}, as functions of the
 fundamental kinematical variables of the processes.
 (cf. \ttt{analysis}, \ttt{record})
 %%%%%
 \item
 \ttt{open\_out} \newline
 With the command, \ttt{open\_out ("{\em <out\_file">})} user-defined
 information like data or ($\to$) \ttt{printf} statements can be
 written out to a user-defined file. The command opens an I/O stream to
 an external file \ttt{{\em <out\_file>}}. (cf. also \ttt{close\_out},
 \ttt{\$out\_file}, \ttt{printf})
 %%%%%
 \item
 \ttt{or} \newline
 This is the standard two-place logical connective that has the value
 true if one of its operands is true, otherwise a value of false. It
 is applied to logical values, e.g. cut expressions. (cf. also
 \ttt{and}, \ttt{not}).
 %%%%%
 \item
 \ttt{outgoing} \newline
 Constructor that specifies particles (or subevents) as outgoing. It is
 used in cuts, analyses or selections, e.g. \ttt{cuts = all Theta > 20
 degree [incoming lepton, outgoing lepton]}. Note that the \ttt{outgoing}
 keyword is redundant and included only for completeness: \ttt{outgoing lepton}
 has the same meaning as \ttt{lepton}.  (cf. also \ttt{beam},
 \ttt{incoming},
 \ttt{cuts}, \ttt{analysis}, \ttt{selection}, \ttt{record})
 %%%%%
 \item
 \ttt{P} \newline
 Unary (binary) observable specifier for the spatial momentum
 $\sqrt{\vec{p}^2}$ of a single (two) particle(s), e.g. \ttt{eval P
 ["W+"]}, \ttt{all P > 200 GeV [b, B]}. (cf. \ttt{eval}, \ttt{cuts},
 \ttt{selection})
 %%%%%
 \item
 \ttt{pbarn} \newline
 Physical unit, stating that a number is in picobarns ($10^{-12}$
 barn). (cf. also \ttt{abarn}, \ttt{fbarn}, \ttt{nbarn})
 %%%%%
 \item
 \ttt{pdf\_builtin} \newline
 This is a beams specifier for \whizard's internal PDF structure
 functions to integrate processes in hadron collisions.
 (cf. \ttt{beams}, \ttt{pdf\_builtin\_photon},
 \ttt{\$pdf\_builtin\_file})
 %%%%%
 \item
 \ttt{pdf\_builtin\_photon} \newline
 This is a beams specifier for \whizard's internal PDF structure
 functions to integrate processes in hadron collisions with a photon as
 initializer of the hard scattering process.
 (cf. \ttt{beams}, \ttt{\$pdf\_builtin\_file})
 %%%%%
 \item
 \ttt{PDG} \newline
 Unary observable specifier that allows to specify the PDG code of a
 particle, e.g. \ttt{eval PDG [e1]}, giving \ttt{11}. (cf. also
 \ttt{eval}, \ttt{cuts}, \ttt{selection})
 %%%%%
 \item
 \ttt{Phi} \newline
 Unary and also binary observable specifier, that as a unary observable
 gives the azimuthal angle of a particle's momentum in the detector
 frame (beam into $+z$ direction). As a binary observable, it gives the
 azimuthal difference between the momenta of two particles: \ttt{eval
 Phi [e1]},  \ttt{all Phi > Pi [jet, jet]}. (cf. also \ttt{eval},
 \ttt{cuts}, \ttt{selection}, \ttt{Theta})
 %%%%%
 \item
 \ttt{photon\_isolation} \newline
 Logical function \ttt{photon\_isolation if {\em <condition>} [{\em
 <list1>} , {\em <list2>}]} that cuts out event where the photons in 
 \ttt{{\em <list1>}} do not fulfill the condition \ttt{{\em
 <condition>}} and are not isolated from hadronic (and electromagnetic)
 activity, i.e. the photon fragmentation. (cf. also \ttt{cluster},
 \ttt{collect}, \ttt{combine}, \ttt{extract}, \ttt{select},
 \ttt{sort}, \ttt{+})
 %%%%%
 \item
 \ttt{Pl} \newline
 Unary (binary) observable specifier for the longitudinal momentum
 ($p_z$ in the c.m. frame) of a single (two) particle(s),
 e.g. \ttt{eval Pl ["W+"]}, \ttt{all Pl > 200 GeV [b,
 B]}. (cf. \ttt{eval}, \ttt{cuts}, \ttt{selection})
 %%%%%
 \item
 \ttt{plot} \newline
 This command defines the necessary information regarding plotting data
 as a graph, in the form of: \ttt{plot {\em <record\_name>} \{ {\em <optional
 arguments>} \}}. The record with name \ttt{{\em <record\_name>}} has to be
 defined, either before or after the plot definition. Possible optional
 arguments of the \ttt{plot} command are the minimal and maximal values
 of the axes (\ttt{x\_min}, \ttt{x\_max}, \ttt{y\_min}, \ttt{y\_max}).
 (cf. \ttt{graph}, \ttt{histogram}, \ttt{record})
 %%%%%
 \item
 \ttt{polarized} \newline
 Constructor to instruct \whizard\ to retain polarization of the
 corresponding particles in the generated events: \ttt{polarized {\em <prt1>}
   [, {\em <prt2>} , ...]}. (cf. also \ttt{unpolarized}, \ttt{simulate},
 \ttt{?polarized\_events})
 %%%%%
 \item
 \ttt{printf} \newline
 Command that allows to print data as screen messages, into logfiles or
 into user-defined output files: \ttt{printf "{\em <string\_expr>}"}. There
 exist format specifiers, very similar to the \ttt{C} command
 \ttt{printf}, e.g. \ttt{printf "\%i" (123)}. (cf. also
 \ttt{open\_out}, \ttt{close\_out}, \ttt{\$out\_file},
 \ttt{?out\_advance}, \ttt{sprintf}, \ttt{\%d}, \ttt{\%i}, \ttt{\%e},
 \ttt{\%f}, \ttt{\%g}, \ttt{\%E}, \ttt{\%F}, \ttt{\%G}, \ttt{\%s})
 %%%%%
 \item
 \ttt{process} \newline
 Allows to set a hard interaction process, either for a decay process
 with name \ttt{{\em <decay\_proc>}} as \ttt{process {\em
 <decay\_proc>} = {\em <mother>} => {\em <daughter1>}, {\em
 <daughter2>}, ...}, or for a scattering process
 with name \ttt{{\em <scat\_proc}} as \ttt{process {\em <scat\_proc>} =
 {\em <in1>}, {\em <in2>} => {\em <out1>}, {\em <out2>}, ...}. Note
 that there can be arbitrarily many processes to be defined in a
 \sindarin\ input file. There are two options for particle/process sums: flavor sums:
 \ttt{{\em <prt1>}:{\em <prt2>}:...}, where all masses have to be identical, and
 inclusive sums, \ttt{{\em <prt1>} + {\em <prt2>} + ...}. The latter can be done on
 the level of individual particles, or sums over whole final
 states. Here, masses can differ, and terms will be translated into
 different process components. The \ttt{process} command also allows for
 optional arguments, e.g. to specify a numerical identifier
 (cf. \ttt{process\_num\_id}), the method how to generate the code for
 the matrix element(s): \ttt{\$method}, possible methods are either
 with the \oMega\ matrix element generator, using template matrix
 elements with different normalizations, or completely internal matrix
 element; for \oMega\ matrix elements there is also the possibility to
 specify possible restrictions (cf. \ttt{\$restrictions}).
 %%%%%
 \item
 \ttt{Pt} \newline
 Unary (binary) observable specifier for the transverse momentum
 ($\sqrt{p_x^2 + p_y^2}$ in the c.m. frame) of a single (two)
 particle(s), e.g. \ttt{eval Pt ["W+"]}, \ttt{all Pt > 200 GeV [b,
 B]}. (cf. \ttt{eval}, \ttt{cuts}, \ttt{selection})
 %%%%%
 \item
 \ttt{Px} \newline
 Unary (binary) observable specifier for the $x$-component of the
 momentum of a single (two) particle(s), e.g. \ttt{eval Px ["W+"]},
 \ttt{all Px > 200 GeV [b, B]}. (cf. \ttt{eval}, \ttt{cuts},
 \ttt{selection})
 %%%%%
 \item
 \ttt{Py} \newline
 Unary (binary) observable specifier for the $y$-component of the
 momentum of a single (two) particle(s), e.g. \ttt{eval Py ["W+"]},
 \ttt{all Py > 200 GeV [b, B]}. (cf. \ttt{eval}, \ttt{cuts},
 \ttt{selection})
 %%%%%
 \item
 \ttt{Pz} \newline
 Unary (binary) observable specifier for the $z$-component of the
 momentum of a single (two) particle(s), e.g. \ttt{eval Pz ["W+"]},
 \ttt{all Pz > 200 GeV [b, B]}. (cf. \ttt{eval}, \ttt{cuts},
 \ttt{selection})
 %%%%%
 \item
 \ttt{quit} \newline
 Command to finish the \whizard\ run (and not execute any further code
 beyond the appearance of \ttt{quit} in the \sindarin\ file. The command
 (which is the same as $\to$ \ttt{exit}) allows for an argument,
 \ttt{quit ({\em <expr>})}, where the expression can be executed, e.g. a
 screen message or an quit code.
 %%%%%
 \item
 \ttt{rad} \newline
 Expression specifying the physical unit of radians for angular
 variables. This is the default in \whizard. (cf. \ttt{degree}, \ttt{mrad}).
 %%%%%
 \item
 \ttt{Rap} \newline
 Unary and also binary observable specifier, that as a unary observable
 gives the rapidity of a particle momentum. The rapidity is given by $y
 = \frac12 \log \left[ (E + p_z)/(E-p_z) \right]$. As a binary
 observable, it gives the rapidity difference between the momenta of
 two particles: \ttt{eval Rap [e1]},  \ttt{all abs (Rap) < 3.5 [jet,
   jet]}. (cf. also \ttt{eval}, \ttt{cuts}, \ttt{selection}, \ttt{Eta},
 \ttt{abs})
 %%%%%
 \item
 \ttt{read\_slha} \newline
 Tells \whizard\ to read in an input file in the SUSY Les Houches accord
 (SLHA), as \ttt{read\_slha ("slha\_file.slha")}. Note that the files
 for the use in \whizard\ should have the suffix \ttt{.slha}.
 (cf. also \ttt{write\_slha}, \ttt{?slha\_read\_decays},
 \ttt{?slha\_read\_input}, \ttt{?slha\_read\_spectrum})
 %%%%%
 \item
 \ttt{real} \newline
 This is a constructor to specify real constants in the input
 file. Strictly speaking, it is a unary function setting the value
 \ttt{real\_val} of the real variable \ttt{real\_var}:
 \ttt{real {\em <real\_var>} = {\em <real\_val>}}. (cf. also \ttt{int} and
 \ttt{complex})
 %%%%%
 \item
 \ttt{real\_epsilon}\\
 Predefined real; the relative uncertainty intrinsic to the floating
 point type of the \fortran\ compiler with which \whizard\ has been
 built.
 %%%%%
 \item
 \ttt{real\_precision}\\
 Predefined integer; the decimal precision of the floating point type
 of the \fortran\ compiler with which \whizard\ has been built.
 %%%%%
 \item
 \ttt{real\_range}\\
 Predefined integer; the decimal range of the floating point type of
 the \fortran\ compiler with which \whizard\ has been built.
 %%%%%
 \item
 \ttt{real\_tiny}\\
 Predefined real; the smallest number which can be represented by the
 floating point type of the \fortran\ compiler with which \whizard\ has
 been built.
 %%%%%
 \item
 \ttt{record} \newline
 The \ttt{record} constructor provides an internal data structure in
 \sindarin\ input files. Its syntax is in general \ttt{record
   {\em <record\_name>} ({\em <cmd\_expr>})}. The \ttt{{\em <cmd\_expr>}} could be the
 definition of a tuple of points for a histogram or an \ttt{eval}
 constructor that tells \whizard\ e.g. by which rule to calculate an
 observable to be stored in the record \ttt{record\_name}. Example:
 \ttt{record h (12)} is a record for a histogram defined under the name
 \ttt{h} with the single data point (bin) at value 12; \ttt{record rap1
 (eval Rap [e1])} defines a record with name \ttt{rap1} which has an
 evaluator to calculate the rapidity (predefined \whizard\ function) of
 an outgoing electron.
 (cf. also \ttt{eval}, \ttt{histogram}, \ttt{plot})
 %%%%%
 \item
 \ttt{renormalization\_scale} \newline
 This is a command, \ttt{renormalization\_scale = {\em <expr>}}, that sets
 the renormalization scale of a process or list of processes. It
 overwrites a possible scale set by the ($\to$) \ttt{scale} command.
 \ttt{{\em <expr>}} can be any kinematic expression that leads to a result of
 momentum dimension one, e.g. \ttt{100 GeV}, \ttt{eval
 Pt [e1]}. (cf. also \ttt{factorization\_scale}).
 %%%%%
 \item
 \ttt{rescan} \newline
 This command allows to rescan event samples with modified model
 parameter, beam structure etc. to recalculate (analysis) observables,
 e.g.: \newline
 \ttt{rescan "{\em <event\_file>}" ({\em <proc\_name>}) \{ {\em <rescan\_setup>}\}}.
 \newline
 \ttt{"{\em <event\_file>}"} is the name of the event file and
 \ttt{{\em <proc\_name>}} is the process whose (existing) event
 file of arbitrary size that is to be rescanned. Several flags allow to
 reconstruct the beams ($\to$ \ttt{?recover\_beams}), to reuse only the
 hard process but rebuild the full events ($\to$
 \ttt{?update\_event}), to recalculate the matrix element ($\to$
 \ttt{?update\_sqme}) or to recalculate the individual event weight ($\to$
 \ttt{?update\_weight}). Further rescan options are redefining model
 parameter input, or defining a completely new alternative setup ($\to$
 \ttt{alt\_setup}) (cf. also \ttt{\$rescan\_input\_format})
 %%%%%
 \item
 \ttt{results} \newline
 Only used in the combination \ttt{show (results)}. Forces \whizard\ to
 print out a results summary for the integrated processes.
 (cf. also \ttt{show})
 %%%%%
 \item
 \ttt{reweight} \newline
 The \ttt{reweight = {\em <expr>}} command allows to give for a process or
 list of processes an alternative weight, given by any kind of scalar
 expression \ttt{{\em <expr>}}, e.g. \ttt{reweight = 0.2} or \ttt{reweight =
 (eval M2 [e1, E1]) / (eval M2 [e2, E2])}. (cf. also \ttt{alt\_setup},
 \ttt{weight}, \ttt{rescan})
 %%%%%
 \item
 \ttt{sample\_format} \newline
 Variable that allows the user to specify additional event formats
 beyond the \whizard\ native binary event format. Its syntax is
 \ttt{sample\_format = {\em <format>}}, where \ttt{{\em <format>}} can be any of
 the following specifiers: \ttt{hepevt}, \ttt{hepevt\_verb}, \ttt{ascii},
 \ttt{athena}, \ttt{debug}, \ttt{long}, \ttt{short}, \ttt{hepmc},
 \ttt{lhef}, \ttt{lha}, \ttt{lha\_verb}, \ttt{stdhep}, \ttt{stdhep\_up}.
 (cf. also \ttt{\$sample}, \ttt{simulate}, \ttt{hepevt}, \ttt{ascii},
 \ttt{athena}, \ttt{debug}, \ttt{long}, \ttt{short}, \ttt{hepmc},
 \ttt{lhef}, \ttt{lha}, \ttt{stdhep}, \ttt{stdhep\_up}, \newline
 \ttt{\$sample\_normalization}, \ttt{?sample\_pacify},
 \ttt{sample\_max\_tries}, \ttt{sample\_split\_n\_evt},
 \ttt{sample\_split\_n\_kbytes})
 %%%%%
 \item
 \ttt{scale} \newline
 This is a command, \ttt{scale = {\em <expr>}}, that sets the kinematic scale
 of a process or list of processes. Unless overwritten explicitly by
 ($\to$) \ttt{factorization\_scale} and/or ($\to$)
 \ttt{renormalization\_scale} it sets both scales. \ttt{{\em <expr>}} can be
 any kinematic expression that leads to a result of momentum dimension
 one, e.g. \ttt{scale = 100 GeV}, \ttt{scale = eval Pt [e1]}.
 %%%%%
 \item
 \ttt{scan} \newline
 Constructor to perform loops over variables or scan over processes in
 the integration procedure. The syntax is \ttt{scan {\em <var>} {\em <var\_name>}
   ({\em <value list>} or  {\em <value\_init>} => {\em <value\_fin>} /{\em <incrementor>}
   {\em <increment>}) \{ {\em <scan\_cmd>} \}}. The variable \ttt{var} can be
 specified if it is not a real, e.g. an integer. \ttt{var\_name} is the
 name of the variable which is also allowed to be a predefined one like
 \ttt{seed}. For the scan, one can either specify an explicit list of
 values \ttt{value list}, or use an initial and final value and a
 rule to increment. The \ttt{scan\_cmd}  can either be just a
 \ttt{show} to print out the scanned variable or the integration of a process.
 Examples are: \ttt{scan seed (32 => 1 // 2) \{ show (seed\_value) \}
 }, which runs the seed down in steps 32, 16, 8, 4, 2, 1 (division by
 two). \ttt{scan mW (75 GeV, 80 GeV => 82 GeV /+ 0.5 GeV,  83 GeV => 90
 GeV /* 1.2) \{ show (sw) \} } scans over the $W$ mass for the values
 75, 80, 80.5, 81, 81.5, 82, 83 GeV, namely one discrete value, steps
 by adding 0.5 GeV, and increase by 20 \% (the latter having no effect
 as it already exceeds the final value). It prints out the
 corresponding value of the effective mixing angle which is defined as
 a dependent variable in the model input file(s). \ttt{scan sqrts (500 GeV =>
   600 GeV /+ 10 GeV) \{ integrate (proc) \} } integrates the process
 \ttt{proc} in eleven increasing 10 GeV steps in center-of-mass energy
 from 500 to 600 GeV. (cf. also \ttt{/+}, \ttt{/+/}, \ttt{/-},
 \ttt{/*}, \ttt{/*/}, \ttt{//})
 %%%%%
 \item
 \ttt{select} \newline
 Subevent function \ttt{select if {\em <condition>} [{\em <list1>} [ ,
   {\em <list2>}]]} that selects all particles in \ttt{{\em <list1>}}
 that satisfy the condition \ttt{{\em <condition>}}. The second
 particle list \ttt{{\em <list2>}} is for conditions that depend on
 binary observables. (cf. also \ttt{collect},
 \ttt{combine}, \ttt{extract}, \ttt{sort}, \ttt{+})
 %%%%%
 \item
 \ttt{select\_b\_jet} \newline
 Subevent function \ttt{select if {\em <condition>} [{\em <list1>} [ ,
   {\em <list2>}]]} that selects all particles in \ttt{{\em <list1>}}
 that are $b$ jets and satisfy the condition \ttt{{\em
 <condition>}}. The second particle list \ttt{{\em <list2>}} is for
 conditions that depend on binary observables. (cf. also \ttt{cluster},
 \ttt{collect}, \ttt{combine}, \ttt{extract}, \ttt{select},
 \ttt{sort}, \ttt{+})
 %%%%%
 \item
 \ttt{select\_c\_jet} \newline
 Subevent function \ttt{select if {\em <condition>} [{\em <list1>} [ ,
   {\em <list2>}]]} that selects all particles in \ttt{{\em <list1>}}
 that are $c$ jets (but {\em not} $b$ jets) and satisfy the condition
 \ttt{{\em <condition>}}. The second particle list \ttt{{\em <list2>}}
 is for conditions that depend on binary observables. (cf. also
 \ttt{cluster}, \ttt{collect}, \ttt{combine}, \ttt{extract},
 \ttt{select}, \ttt{sort}, \ttt{+})
 %%%%%
 \item
 \ttt{select\_light\_jet} \newline
 Subevent function \ttt{select if {\em <condition>} [{\em <list1>} [ ,
   {\em <list2>}]]} that selects all particles in \ttt{{\em <list1>}}
 that are light(-flavor) jets and satisfy the condition
 \ttt{{\em <condition>}}. The second particle list \ttt{{\em <list2>}}
 is for conditions that depend on binary observables. (cf. also
 \ttt{cluster}, \ttt{collect}, \ttt{combine}, \ttt{extract},
 \ttt{select}, \ttt{sort}, \ttt{+})
 %%%%%
 \item
 \ttt{select\_non\_b\_jet} \newline
 Subevent function \ttt{select if {\em <condition>} [{\em <list1>} [ ,
 {\em <list2>}]]} that selects all particles in \ttt{{\em <list1>}}
 that are {\em not} $b$ jets ($c$ and light jets) and satisfy the
 condition \ttt{{\em <condition>}}. The second particle list \ttt{{\em
 <list2>}} is for conditions that depend on binary
 observables. (cf. also \ttt{cluster}, \ttt{collect}, \ttt{combine},
 \ttt{extract}, \ttt{select}, \ttt{sort}, \ttt{+})
 %%%%%
 \item
 \ttt{selection} \newline
 Command that allows to select particular final states in an analysis
 selection, \ttt{selection = {\em <log\_expr>}}. The term \ttt{log\_expr} can
 be any kind of logical expression. The syntax matches exactly
 the one of the ($\to$) \ttt{cuts} command. E.g. \ttt{selection = any
 PDG == 13} is an electron selection in a lepton sample.
 %%%%%
 \item
 \ttt{sgn} \newline
 Numerical function for integer and real numbers that gives the sign of
 its argument: \ttt{sgn ({\em <num\_val>})} yields $+1$ if \ttt{{\em
 <num\_val>}} is positive or zero, and $-1$ otherwise. (cf. also
 \ttt{abs}, \ttt{conjg}, \ttt{mod}, \ttt{modulo})
 %%%%%
 \item
 \ttt{short} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of the short variant of HEPEVT ASCII event
 files. (cf. also \ttt{\$sample}, \ttt{sample\_format})
 %%%%%
 \item
 \ttt{show} \newline
 This is a unary function that is operating on specific constructors in
 order to print them out in the \whizard\ screen output as well as the
 log file \ttt{whizard.log}. Examples are \ttt{show({\em <parameter\_name>})}
 to issue a specific parameter from a model or a constant defined in a
 \sindarin\ input file, \ttt{show(integral({\em <proc\_name>}))},
 \ttt{show(library)}, \ttt{show(results)}, or \ttt{show({\em <var>})} for any
 arbitrary variable. Further possibilities are \ttt{show(real)},
 \ttt{show(string)}, \ttt{show(logical)} etc. to allow to show all
 defined real, string, logical etc. variables, respectively.
 (cf. also \ttt{library}, \ttt{results})
 %%%%%
 \item
 \ttt{simulate} \newline
 This command invokes the generation of events for the process
 \ttt{proc} by means of \ttt{simulate ({\em <proc>})}.
 Optional arguments: \ttt{\$sample}, \ttt{sample\_format},
 \ttt{checkpoint} (cf. also \ttt{integrate}, \ttt{luminosity},
 \ttt{n\_events}, \ttt{\$sample}, \ttt{sample\_format},
 \ttt{checkpoint}, \ttt{?unweighted}, \ttt{safety\_factor},
 \ttt{?negative\_weights}, \ttt{sample\_max\_tries},
 \ttt{sample\_split\_n\_evt}, \ttt{sample\_split\_n\_kbytes})
 %%%%%
 \item
 \ttt{sin} \newline
 Numerical function \ttt{sin ({\em <num\_val>})} that calculates the
 sine trigonometric function of real and complex numerical numbers or
 variables. (cf. also \ttt{cos}, \ttt{tan}, \ttt{asin}, \ttt{acos},
 \ttt{atan})
 %%%%%
 \item
 \ttt{sinh} \newline
 Numerical function \ttt{sinh ({\em <num\_val>})} that calculates the
 hyperbolic sine function of real and complex numerical numbers or
 variables. Note that its inverse function is part of the
 \ttt{Fortran2008} status and hence not realized. (cf. also \ttt{cosh},
 \ttt{tanh})
 %%%%%
 \item
 \ttt{sort} \newline
 Subevent function that allows to sort a particle list/subevent either
 by increasing PDG code: \ttt{sort [{\em <particles>}]} (particles
 first, then antiparticles). Alternatively, it can sort according to a
 unary or binary particle observable (in that case there is a second
 particle list, where the first particle is taken as a reference):
 \ttt{sort by {\em <observable>} [{\em <particles>} [, {\em
 <ref\_particles>}]]}. (cf. also \ttt{extract}, \ttt{combine},
 \ttt{collect}, \ttt{join}, \ttt{by}, \ttt{+})
 %%%%%
 \item
 \ttt{sprintf} \newline
 Command that allows to print data into a string variable: \ttt{sprintf
 "{\em <string\_expr>}"}. There exist format specifiers, very similar
 to the \ttt{C} command \ttt{sprintf}, e.g. \ttt{sprintf "\%i"
 (123)}. (cf. \ttt{printf}, \ttt{\%d}, \ttt{\%i}, \ttt{\%e},
 \ttt{\%f}, \ttt{\%g}, \ttt{\%E}, \ttt{\%F}, \ttt{\%G}, \ttt{\%s})
 %%%%%
 \item
 \ttt{sqrt} \newline
 Numerical function \ttt{sqrt ({\em <num\_val>})} that calculates the
 square root of real and complex numerical numbers or
 variables. (cf. also \ttt{exp}, \ttt{log}, \ttt{log10})
 %%%%%
 \item
 \ttt{sqrts\_hat} \newline
 Real variable that accesses the partonic energy of a hard-scattering
 process. It can be used in cuts or in an analysis, e.g. \ttt{cuts =
 sqrts\_hat > {\em <num>} [ {\em <phys\_unit>} ]}. The physical unit
 can be one of the following \ttt{eV}, \ttt{keV}, \ttt{MeV}, \ttt{GeV},
 and \ttt{TeV}. (cf. also \ttt{sqrts}, \ttt{cuts}, \ttt{record})
 %%%%%
 \item
 \ttt{stable} \newline
 This constructor allows particles in the final states of processes in
 decay cascade set-up to be set as stable, and not letting them
 decay. The syntax is \ttt{stable {\em <prt\_name>}} (cf. also \ttt{unstable})
 %%%%%
 \item
 \ttt{stdhep} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of binary StdHEP event files based on the HEPEVT common
 block. (cf. also \ttt{\$sample}, \ttt{sample\_format})
 %%%%%
 \item
 \ttt{stdhep\_up} \newline
 Specifier for the \ttt{sample\_format} command to demand the
 generation of binary StdHEP event files based on the HEPRUP/HEPEUP common
 blocks. (cf. also \ttt{\$sample}, \ttt{sample\_format})
 %%%%%
 \item
 \ttt{tan} \newline
 Numerical function \ttt{tan ({\em <num\_val>})} that calculates the
 tangent trigonometric function of real and complex numerical numbers or
 variables. (cf. also \ttt{sin}, \ttt{cos}, \ttt{asin}, \ttt{acos},
 \ttt{atan})
 %%%%%
 \item
 \ttt{tanh} \newline
 Numerical function \ttt{tanh ({\em <num\_val>})} that calculates the
 hyperbolic tangent function of real and complex numerical numbers or
 variables. Note that its inverse function is part of the
 \ttt{Fortran2008} status and hence not realized. (cf. also \ttt{cosh},
 \ttt{sinh})
 %%%%%
 \item
 \ttt{TeV} \newline
 Physical unit, for energies in $10^{12}$ electron volt. (cf. also
 \ttt{eV}, \ttt{keV}, \ttt{MeV}, \ttt{meV}, \ttt{GeV})
 %%%%
 \item
 \ttt{then} \newline
 Mandatory phrase in a conditional clause: \ttt{if {\em <log\_expr>} then
   {\em <expr 1>} \ldots endif}. (cf. also \ttt{if}, \ttt{else}, \ttt{elsif},
 \ttt{endif}).
 %%%%%
 \item
 \ttt{Theta} \newline
 Unary and also binary observable specifier, that as a unary observable
 gives the angle between a particle's momentum and the beam axis ($+z$
 direction). As a binary observable, it gives the angle enclosed
 between the momenta of the two particles: \ttt{eval Theta [e1]},
 \ttt{all Theta > 30 degrees [jet, jet]}. (cf. also \ttt{eval},
 \ttt{cuts}, \ttt{selection}, \ttt{Phi}, \ttt{Theta\_star})
 %%%%%
 \item
 \ttt{Theta\_star} \newline
 Binary observable specifier, that gives the polar angle enclosed
 between the momenta of the two particles in the rest frame of the
 mother particle (momentum sum of the two particle): \ttt{eval
 Theta\_star [jet, jet]}. (cf. also \ttt{eval},
 \ttt{cuts}, \ttt{selection}, \ttt{Theta})
 %%%%%
 \item
 \ttt{true} \newline
 Constructor stating that a logical expression or variable is true,
 e.g. \ttt{?{\em <log\_var>} = true}. (cf. also \ttt{false}).
 %%%%%
 \item
 \ttt{unpolarized} \newline
 Constructor to force \whizard\ to discard polarization of the
 corresponding particles in the generated events: \ttt{unpolarized {\em <prt1>}
   [, {\em <prt2>} , ...]}. (cf. also \ttt{polarized}, \ttt{simulate},
 \ttt{?polarized\_events})
 %%%%%
 \item
 \ttt{unstable} \newline
 This constructor allows to let final state particles of the hard
 interaction undergo a subsequent (cascade) decay (in the on-shell
 approximation). For this the user has to define the list of desired
 \begin{figure}
   \begin{Verbatim}[frame=single]
     process zee =   Z => e1, E1
     process zuu =   Z => u, U
     process zz = e1, E1 => Z, Z
     compile
     integrate (zee) { iterations = 1:100 }
     integrate (zuu) { iterations = 1:100 }
     sqrts = 500 GeV
     integrate (zz) { iterations = 3:5000, 2:5000 }
     unstable Z (zee, zuu)
  \end{Verbatim}
   \caption{\label{fig:ex_unstable} \sindarin\ input file for unstable
     particles and inclusive decays.}
 \end{figure}
 decay channels as \ttt{unstable {\em <mother>} ({\em <decay1>}, {\em <decay2>}, ....)},
 where \ttt{mother} is the mother particle, and the argument is a list
 of decay channels. Note that -- unless the \ttt{?auto\_decays = true}
 flag has been set -- these decay channels have to be provided by the
 user as  in the example in Fig. \ref{fig:ex_unstable}. First, the $Z$
 decays to electrons and up quarks are generated, then $ZZ$ production
 at a 500 GeV ILC is called, and then both $Z$s are decayed according
 to the probability distribution of the two generated decay matrix
 elements. This obviously allows also for inclusive decays.
 (cf. also \ttt{stable}, \ttt{?auto\_decays})
 %%%%%
 \item
 \ttt{weight} \newline
 This is a command, \ttt{weight = {\em <expr>}}, that allows to specify a
 weight for a process or list of processes. \ttt{{\em <expr>}} can be
 any expression that leads to a scalar result, e.g. \ttt{weight = 0.2},
 \ttt{weight = eval Pt [jet]}.  (cf. also \ttt{rescan},
 \ttt{alt\_setup}, \ttt{reweight})
 %%%%%
 \item
 \ttt{write\_analysis} \newline
 The \ttt{write\_analysis} statement tells \whizard\ to write the
 analysis setup by the user for the \sindarin\ input file under
 consideration. If no \ttt{\$out\_file} is provided, the histogram
 tables/plot data etc. are written to the default file
 \ttt{whizard\_analysis.dat}. Note that the related command
 \ttt{compile\_analysis} does the same as \ttt{write\_analysis} but in
 addition invokes the \whizard\ \LaTeX routines for producing
 postscript or PDF output of the data.
 (cf. also \ttt{\$out\_file}, \ttt{compile\_analysis})
 %%%%%
 \item
 \ttt{write\_slha} \newline
 Demands \whizard\ to write out a file in the SUSY Les Houches accord
 (SLHA) format. (cf. also \ttt{read\_slha}, \ttt{?slha\_read\_decays},
 \ttt{?slha\_read\_input}, \ttt{?slha\_read\_spectrum})
 %%%%%
 \end{itemize}
 \section{Variables}
 \subsection{Rebuild Variables}
 \begin{itemize}
 \item
 \ttt{?rebuild\_events} \qquad (default: \ttt{false}) \newline
 This logical variable, if set \ttt{true} triggers \whizard\ to newly
 create an event sample, even if nothing seems to have changed,
 including the MD5 checksum. This can be used when manually
 manipulating some settings. (cf also \ttt{?rebuild\_grids},
 \ttt{?rebuild\_library}, \ttt{?rebuild\_phase\_space})
 %%%%%
 \item
 \ttt{?rebuild\_grids} \qquad (default: \ttt{false}) \newline
 The logical variable \ttt{?rebuild\_grids} forces \whizard\ to newly
 create the VAMP grids when using VAMP as an integration method, even
 if they are already present. (cf. also \ttt{?rebuild\_events},
 \ttt{?rebuild\_library}, \ttt{?rebuild\_phase\_space})
 %%%%%
 \item
 \ttt{?rebuild\_library} \qquad (default: \ttt{false}) \newline
 The logical variable \ttt{?rebuild\_library = true/false} specifies
 whether the library(-ies) for the matrix element code for processes is
 re-generated (incl. possible Makefiles etc.) by the corresponding ME
 method (e.g. if the process has been changed, but not its name). This
 can also be set as a command-line option \ttt{whizard --rebuild}. The
 default is \ttt{false}, i.e. code is never re-generated if it is
 present and the MD5 checksum is valid.
 (cf. also \ttt{?recompile\_library}, \ttt{?rebuild\_grids},
 \ttt{?rebuild\_phase\_space})
 %%%%%
 \item
 \ttt{?rebuild\_phase\_space} \qquad (default: \ttt{false}) \newline
 This logical variable, if set \ttt{true}, triggers recreation of the
 phase space file by \whizard\. (cf. also \ttt{?rebuild\_events},
 \ttt{?rebuild\_grids}, \ttt{?rebuild\_library})
 %%%%%
 \item
 \ttt{?recompile\_library} \qquad (default: \ttt{false}) \newline
 The logical variable \ttt{?recompile\_library = true/false} specifies
 whether the library(-ies) for the matrix element code for processes is
 re-compiled (e.g. if the process code has been manually modified by
 the user). This can also be set as a command-line option \ttt{whizard
   --recompile}. The default is \ttt{false}, i.e. code is never
 re-compiled if its corresponding object file is present. (cf. also
 \ttt{?rebuild\_library})
 %%%%%
 \end{itemize}
 \subsection{Standard Variables}
 \begin{itemize}
 \input{variables}
 \end{itemize}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \clearpage
 \section*{Acknowledgements}
 
 We would like to thank E.~Boos, R.~Chierici, K.~Desch, M.~Kobel,
 F.~Krauss, P.M.~Manakos, N.~Meyer, K.~M\"onig, H.~Reuter, T.~Robens,
 S.~Rosati, J.~Schumacher, M.~Schumacher, and C.~Schwinn who
 contributed to \whizard\ by their suggestions, bits of codes and
 valuable remarks and/or used several versions of the program for
 real-life applications and thus helped a lot in debugging and
 improving the code.  Special thanks go to A.~Vaught and J.~Weill for
 their continuos efforts on improving the g95 and gfortran compilers,
 respectively.
 
 %\end{fmffile}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%% References
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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 %\cite{Alioli:2013nda}
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   %%CITATION = doi:10.1016/j.cpc.2013.10.020;%%
 
 %\cite{Speckner:2010zi}
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   C.~Speckner,
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 %\cite{Chivukula:2006cg}
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   R.~S.~Chivukula, B.~Coleppa, S.~Di Chiara, E.~H.~Simmons, H.~-J.~He,
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   %%CITATION = HEP-PH/0607124;%%
 
 %\cite{Chivukula:2005xm}
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   %%CITATION = HEP-PH/0504114;%%
 
 %\cite{Ohl:2008ri}
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   %%CITATION = ARXIV:0809.0023;%%
 
 %\cite{Ohl:2002jp}
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   %%CITATION = HEP-TH/0212224;%%
 
 %\cite{Reuter:2009ex}
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 %\cite{Kalinowski:2008fk}
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   %%CITATION = ARXIV:0809.3997;%%
 
 %\cite{Robens:2008sa}
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   %%CITATION = ARXIV:0803.4161;%%
 
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   %%CITATION = HEP-PH/0411213;%%
 
 %\cite{Kilian:2006eh}
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   %%CITATION = HEP-PH/0609119;%%
 
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   %%CITATION = HEP-PH/0406098;%%
 
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 %%%%% FeynRules %%%%%
 
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 %%%%% WHIZARD NLO %%%%%
 
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 \end{thebibliography}
 
 \end{document}
Index: trunk/tests/functional_tests/cmdline_1.sh
===================================================================
--- trunk/tests/functional_tests/cmdline_1.sh	(revision 0)
+++ trunk/tests/functional_tests/cmdline_1.sh	(revision 8347)
@@ -0,0 +1,12 @@
+#!/bin/sh
+### Check WHIZARD control structures
+echo "Running script $0"
+script=`basename @script@`
+./run_whizard.sh @script@ \
+    -e "'int i = 1'" \
+    -f ${script}_a.sin \
+    --execute \'i = 4  a = 12\' \
+    --file ${script}_b.sin \
+    -e \"int q = 3\" \
+    --no-logging --no-model --no-library
+diff ref-output/$script.ref $script.log
Index: trunk/tests/functional_tests/Makefile.am
===================================================================
--- trunk/tests/functional_tests/Makefile.am	(revision 8346)
+++ trunk/tests/functional_tests/Makefile.am	(revision 8347)
@@ -1,790 +1,797 @@
 ## Makefile.am -- Makefile for executable WHIZARD test scripts
 ##
 ## Process this file with automake to produce Makefile.in
 ##
 ########################################################################
 #
 # Copyright (C) 1999-2019 by
 #     Wolfgang Kilian <kilian@physik.uni-siegen.de>
 #     Thorsten Ohl <ohl@physik.uni-wuerzburg.de>
 #     Juergen Reuter <juergen.reuter@desy.de>
 #     with contributions from
 #     cf. main AUTHORS file
 #
 # WHIZARD is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 2, or (at your option)
 # any later version.
 #
 # WHIZARD is distributed in the hope that it will be useful, but
 # WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 #
 ########################################################################
 
 WHIZARD_DRIVER = run_whizard.sh
 
 TESTS_DEFAULT = \
     empty.run \
     fatal.run \
+    cmdline_1.run \
     structure_1.run \
     structure_2.run \
     structure_3.run \
     structure_4.run \
     structure_5.run \
     structure_6.run \
     structure_7.run \
     structure_8.run \
     vars.run \
     extpar.run \
     testproc_1.run \
     testproc_2.run \
     testproc_3.run \
     testproc_4.run \
     testproc_5.run \
     testproc_6.run \
     testproc_7.run \
     testproc_8.run \
     testproc_9.run \
     testproc_10.run \
     testproc_11.run \
     testproc_12.run \
     template_me_1.run \
     template_me_2.run \
     model_scheme_1.run \
     rebuild_1.run \
     rebuild_4.run \
     susyhit.run \
     helicity.run \
     libraries_4.run \
     job_id_1.run \
     pack_1.run
 
 XFAIL_TESTS_DEFAULT =
 
 TESTS_REQ_FASTJET = \
     analyze_4.run \
     bjet_cluster.run \
     openloops_12.run \
     openloops_13.run
 
 TESTS_REQ_OCAML = \
     libraries_1.run \
     libraries_2.run \
     libraries_3.run \
     rebuild_2.run \
     rebuild_3.run \
     rebuild_5.run \
     defaultcuts.run \
     cuts.run \
     model_change_1.run \
     model_change_2.run \
     model_change_3.run \
     model_test.run \
     job_id_2.run \
     job_id_3.run \
     job_id_4.run \
     qedtest_1.run \
     qedtest_2.run \
     qedtest_3.run \
     qedtest_4.run \
     qedtest_5.run \
     qedtest_6.run \
     qedtest_7.run \
     qedtest_8.run \
     qedtest_9.run \
     qedtest_10.run \
     rambo_vamp_1.run \
     rambo_vamp_2.run \
     beam_setup_1.run \
     beam_setup_2.run \
     beam_setup_3.run \
     beam_setup_4.run \
     beam_setup_5.run \
     qcdtest_1.run \
     qcdtest_2.run \
     qcdtest_3.run \
     qcdtest_4.run \
     qcdtest_5.run \
     qcdtest_6.run \
     observables_1.run \
     observables_2.run \
     event_weights_1.run \
     event_weights_2.run \
     event_eff_1.run \
     event_eff_2.run \
     event_dump_1.run \
     event_dump_2.run \
     reweight_1.run \
     reweight_2.run \
     reweight_3.run \
     reweight_4.run \
     reweight_5.run \
     reweight_6.run \
     reweight_7.run \
     reweight_8.run \
     analyze_1.run \
     analyze_2.run \
     analyze_5.run \
     analyze_6.run \
     colors.run \
     colors_2.run \
     colors_hgg.run \
     alphas.run \
     jets_xsec.run \
     lhef_1.run \
     lhef_2.run \
     lhef_3.run \
     lhef_4.run \
     lhef_5.run \
     lhef_6.run \
     lhef_7.run \
     lhef_8.run \
     lhef_9.run \
     lhef_10.run \
     lhef_11.run \
     stdhep_1.run \
     stdhep_2.run \
     stdhep_3.run \
     stdhep_4.run \
     stdhep_5.run \
     stdhep_6.run \
     select_1.run \
     select_2.run \
     fatal_beam_decay.run \
     smtest_1.run \
     smtest_2.run \
     smtest_3.run \
     smtest_4.run \
     smtest_5.run \
     smtest_6.run \
     smtest_7.run \
     smtest_8.run \
     smtest_9.run \
     smtest_10.run \
     smtest_11.run \
     smtest_12.run \
     smtest_13.run \
     smtest_14.run \
     smtest_15.run \
     smtest_16.run \
     photon_isolation_1.run \
     photon_isolation_2.run \
     resonances_1.run \
     resonances_2.run \
     resonances_3.run \
     resonances_4.run \
     resonances_5.run \
     resonances_6.run \
     resonances_7.run \
     resonances_8.run \
     resonances_9.run \
     resonances_10.run \
     resonances_11.run \
     resonances_12.run \
     mssmtest_1.run \
     mssmtest_2.run \
     mssmtest_3.run \
     sm_cms_1.run \
     ufo_1.run \
     ufo_2.run \
     ufo_3.run \
     ufo_4.run \
     nlo_1.run \
     nlo_2.run \
     nlo_3.run \
     nlo_4.run \
     nlo_5.run \
     nlo_6.run \
     nlo_decay_1.run \
     real_partition_1.run \
     fks_res_1.run \
     fks_res_2.run \
     fks_res_3.run \
     openloops_1.run \
     openloops_2.run \
     openloops_3.run \
     openloops_4.run \
     openloops_5.run \
     openloops_6.run \
     openloops_7.run \
     openloops_8.run \
     openloops_9.run \
     openloops_10.run \
     openloops_11.run \
     recola_1.run \
     recola_2.run \
     recola_3.run \
     recola_4.run \
     recola_5.run \
     recola_6.run \
     recola_7.run \
     recola_8.run \
     powheg_1.run \
     spincor_1.run \
     show_1.run \
     show_2.run \
     show_3.run \
     show_4.run \
     show_5.run \
     method_ovm_1.run \
     multi_comp_1.run \
     multi_comp_2.run \
     multi_comp_3.run \
     multi_comp_4.run \
     flvsum_1.run \
     br_redef_1.run \
     decay_err_1.run \
     decay_err_2.run \
     decay_err_3.run \
     polarized_1.run \
     pdf_builtin.run \
     ep_1.run \
     ep_2.run \
     ep_3.run \
     circe1_1.run \
     circe1_2.run \
     circe1_3.run \
     circe1_4.run \
     circe1_5.run \
     circe1_6.run \
     circe1_7.run \
     circe1_8.run \
     circe1_9.run \
     circe1_10.run \
     circe1_photons_1.run \
     circe1_photons_2.run \
     circe1_photons_3.run \
     circe1_photons_4.run \
     circe1_photons_5.run \
     circe1_errors_1.run \
     circe2_1.run \
     circe2_2.run \
     circe2_3.run \
     ewa_1.run \
     ewa_2.run \
     ewa_3.run \
     ewa_4.run \
     isr_1.run \
     isr_2.run \
     isr_3.run \
     isr_4.run \
     isr_5.run \
     epa_1.run \
     epa_2.run \
     isr_epa_1.run \
     ilc.run \
     gaussian_1.run \
     gaussian_2.run \
     beam_events_1.run \
     beam_events_2.run \
     beam_events_3.run \
     beam_events_4.run \
     energy_scan_1.run \
     restrictions.run \
     process_log.run \
     shower_err_1.run \
     parton_shower_1.run \
     parton_shower_2.run \
     hadronize_1.run \
     mlm_matching_fsr.run \
     user_cuts.run \
     user_prc_threshold_1.run \
     cascades2_phs_1.run \
     user_prc_threshold_2.run \
     vamp2_1.run \
     vamp2_2.run
 
 XFAIL_TESTS_REQ_OCAML = \
     colors_hgg.run \
     hadronize_1.run \
     user_cuts.run
 
 TESTS_REQ_HEPMC = \
     hepmc_1.run \
     hepmc_2.run \
     hepmc_3.run \
     hepmc_4.run \
     hepmc_5.run \
     hepmc_6.run \
     hepmc_7.run \
     hepmc_8.run \
     hepmc_9.run \
     hepmc_10.run
 XFAIL_TESTS_REQ_HEPMC =
 
 TESTS_REQ_LCIO = \
     lcio_1.run \
     lcio_2.run \
     lcio_3.run \
     lcio_4.run \
     lcio_5.run \
     lcio_6.run \
     lcio_7.run \
     lcio_8.run \
     lcio_9.run \
     lcio_10.run
 XFAIL_TESTS_REQ_LCIO =
 
 TESTS_REQ_LHAPDF5 = \
     lhapdf5.run
 TESTS_REQ_LHAPDF6 = \
     lhapdf6.run
 XFAIL_TESTS_REQ_LHAPDF5 =
 XFAIL_TESTS_REQ_LHAPDF6 =
 
 TESTS_STATIC = \
     static_1.run \
     static_2.run
 XFAIL_TESTS_STATIC =
 
 TESTS_REQ_PYTHIA6 = \
     pythia6_1.run \
     pythia6_2.run \
     pythia6_3.run \
     pythia6_4.run \
     tauola_1.run \
     tauola_2.run \
     isr_5.run \
     mlm_pythia6_isr.run \
     mlm_matching_isr.run
 XFAIL_TESTS_REQ_PYTHIA6 =
 
 TESTS_REQ_PYTHIA8 =
 #    pythia8_1.run \
 #    pythia8_2.run
 XFAIL_TESTS_REQ_PYTHIA8 =
 
 TESTS_REQ_EV_ANA = \
     analyze_3.run
 XFAIL_TESTS_REQ_EV_ANA =
 
 TESTS_REQ_GAMELAN = \
     analyze_3.run
 
 TEST_DRIVERS_RUN = \
     $(TESTS_DEFAULT) \
     $(TESTS_REQ_OCAML) \
     $(TESTS_REQ_LHAPDF5) \
     $(TESTS_REQ_LHAPDF6) \
     $(TESTS_REQ_HEPMC) \
     $(TESTS_REQ_LCIO) \
     $(TESTS_REQ_FASTJET) \
     $(TESTS_REQ_PYTHIA6) \
     $(TESTS_REQ_EV_ANA) \
     $(TESTS_STATIC)
 
 TEST_DRIVERS_SH = $(TEST_DRIVERS_RUN:.run=.sh)
 
 ########################################################################
 
 TESTS = 
 XFAIL_TESTS =
 TESTS_SRC =
 
 TESTS += $(TESTS_DEFAULT)
 XFAIL_TESTS += $(XFAIL_TESTS_DEFAULT)
 
 TESTS += $(TESTS_REQ_OCAML)
 XFAIL_TESTS += $(XFAIL_TESTS_REQ_OCAML)
 
 TESTS += $(TESTS_REQ_HEPMC)
 XFAIL_TESTS += $(XFAIL_TESTS_REQ_HEPMC)
 
 TESTS += $(TESTS_REQ_LCIO)
 XFAIL_TESTS += $(XFAIL_TESTS_REQ_LCIO)
 
 TESTS += $(TESTS_REQ_FASTJET)
 XFAIL_TESTS += $(XFAIL_TESTS_REQ_FASTJET)
 
 TESTS += $(TESTS_REQ_LHAPDF5)
 XFAIL_TESTS += $(XFAIL_TESTS_REQ_LHAPDF5)
 
 TESTS += $(TESTS_REQ_LHAPDF6)
 XFAIL_TESTS += $(XFAIL_TESTS_REQ_LHAPDF6)
 
 TESTS += $(TESTS_REQ_PYTHIA6)
 XFAIL_TESTS += $(XFAIL_TESTS_REQ_PYTHIA6)
 
 TESTS += $(TESTS_REQ_PYTHIA8)
 XFAIL_TESTS += $(XFAIL_TESTS_REQ_PYTHIA8)
 
 TESTS += $(TESTS_REQ_EV_ANA)
 XFAIL_TESTS += $(XFAIL_TESTS_REQ_EV_ANA)
 
 TESTS += $(TESTS_STATIC)
 XFAIL_TESTS += $(XFAIL_TESTS_STATIC)
 
 
 EXTRA_DIST = $(TEST_DRIVERS_SH) \
     $(TESTS_SRC)
 
 ########################################################################
 
 VPATH = $(srcdir)
 
 SUFFIXES = .sh .run
 
 .sh.run:
 	@rm -f $@
 	@if test -f $(top_builddir)/share/tests/functional_tests/$*.sin; then \
 		$(SED) 's|@script@|$(top_builddir)/share/tests/functional_tests/$*|g' $< > $@; \
 	elif test -f $(top_srcdir)/share/tests/functional_tests/$*.sin; then \
 		$(SED) 's|@script@|$(top_srcdir)/share/tests/functional_tests/$*|g' $< > $@; \
 	else \
 		echo "$*.sin not found!" 1>&2; \
 		exit 2; \
 	fi
 	@chmod +x $@
 
+cmdline_1.run: cmdline_1_a.sin cmdline_1_b.sin
+cmdline_1_a.sin: $(top_builddir)/share/tests/functional_tests/cmdline_1_a.sin
+	cp $< $@
+cmdline_1_b.sin: $(top_builddir)/share/tests/functional_tests/cmdline_1_b.sin
+	cp $< $@
+
 structure_2.run: structure_2_inc.sin
 structure_2_inc.sin: $(top_builddir)/share/tests/functional_tests/structure_2_inc.sin
 	cp $< $@
 
 testproc_3.run: testproc_3.phs
 testproc_3.phs: $(top_builddir)/share/tests/functional_tests/testproc_3.phs
 	cp $< $@
 
 static_1.run: static_1.exe.sin
 static_1.exe.sin: $(top_builddir)/share/tests/functional_tests/static_1.exe.sin
 	cp $< $@
 static_2.run: static_2.exe.sin
 static_2.exe.sin: $(top_builddir)/share/tests/functional_tests/static_2.exe.sin
 	cp $< $@
 
 susyhit.run: susyhit.in
 user_cuts.run: user_cuts.f90
 user_cuts.f90: $(top_builddir)/share/tests/functional_tests/user_cuts.f90
 	cp $< $@
 
 model_test.run: tdefs.$(FC_MODULE_EXT) tglue.$(FC_MODULE_EXT) \
 	threeshl.$(FC_MODULE_EXT) tscript.$(FC_MODULE_EXT)
 tdefs.mod: $(top_builddir)/src/models/threeshl_bundle/tdefs.$(FC_MODULE_EXT)
 	cp $< $@
 tglue.mod: $(top_builddir)/src/models/threeshl_bundle/tglue.$(FC_MODULE_EXT)
 	cp $< $@
 tscript.mod: $(top_builddir)/src/models/threeshl_bundle/tscript.$(FC_MODULE_EXT)
 	cp $< $@
 threeshl.mod: $(top_builddir)/src/models/threeshl_bundle/threeshl.$(FC_MODULE_EXT)
 	cp $< $@
 
 WT_OCAML_NATIVE_EXT=opt
 
 if OCAML_AVAILABLE
 OMEGA_QED = $(top_builddir)/omega/bin/omega_QED.$(WT_OCAML_NATIVE_EXT)
 OMEGA_QCD = $(top_builddir)/omega/bin/omega_QCD.$(WT_OCAML_NATIVE_EXT)
 OMEGA_MSSM = $(top_builddir)/omega/bin/omega_MSSM.$(WT_OCAML_NATIVE_EXT)
 
 omega_MSSM.$(WT_OMEGA_CACHE_SUFFIX): $(OMEGA_MSSM)
 	$(OMEGA_MSSM) -initialize .
 
 UFO_TAG_FILE = __init__.py
 UFO_MODELPATH = ../models/UFO
 
 ufo_1.run: ufo_1_SM/$(UFO_TAG_FILE)
 ufo_2.run: ufo_2_SM/$(UFO_TAG_FILE)
 ufo_3.run: ufo_3_models/ufo_3_SM/$(UFO_TAG_FILE)
 ufo_4.run: ufo_4_models/ufo_4_SM/$(UFO_TAG_FILE)
 
 ufo_1_SM/$(UFO_TAG_FILE): $(UFO_MODELPATH)/SM/$(UFO_TAG_FILE)
 	mkdir -p ufo_1_SM
 	cp $(UFO_MODELPATH)/SM/*.py ufo_1_SM
 ufo_2_SM/$(UFO_TAG_FILE): $(UFO_MODELPATH)/SM/$(UFO_TAG_FILE)
 	mkdir -p ufo_2_SM
 	cp $(UFO_MODELPATH)/SM/*.py ufo_2_SM
 ufo_3_models/ufo_3_SM/$(UFO_TAG_FILE): $(UFO_MODELPATH)/SM/$(UFO_TAG_FILE)
 	mkdir -p ufo_3_models/ufo_3_SM
 	cp $(UFO_MODELPATH)/SM/*.py ufo_3_models/ufo_3_SM
 ufo_4_models/ufo_4_SM/$(UFO_TAG_FILE): $(UFO_MODELPATH)/SM/$(UFO_TAG_FILE)
 	mkdir -p ufo_4_models/ufo_4_SM
 	cp $(UFO_MODELPATH)/SM/*.py ufo_4_models/ufo_4_SM
 
 $(UFO_MODELPATH)/SM/$(UFO_TAG_FILE): $(top_srcdir)/omega/tests/UFO/SM/$(UFO_TAG_FILE)
 	$(MAKE) -C $(UFO_MODELPATH)/SM all
 
 endif OCAML_AVAILABLE
 
 if MPOST_AVAILABLE
 $(TESTS_REQ_GAMELAN): gamelan.sty
 gamelan.sty: $(top_builddir)/src/gamelan/gamelan.sty
 	cp $< $@
 
 $(top_builddir)/src/gamelan/gamelan.sty:
 	$(MAKE) -C $(top_builddir)/src/gamelan gamelan.sty
 endif
 
 noinst_PROGRAMS = 
 
 if OCAML_AVAILABLE
 noinst_PROGRAMS += resonances_1_count
 resonances_1_count_SOURCES = resonances_1_count.f90
 resonances_1.run: resonances_1_count
 
 noinst_PROGRAMS += resonances_2_count
 resonances_2_count_SOURCES = resonances_2_count.f90
 resonances_2.run: resonances_2_count
 
 noinst_PROGRAMS += resonances_3_count
 resonances_3_count_SOURCES = resonances_3_count.f90
 resonances_3.run: resonances_3_count
 
 noinst_PROGRAMS += resonances_4_count
 resonances_4_count_SOURCES = resonances_4_count.f90
 resonances_4.run: resonances_4_count
 
 noinst_PROGRAMS += resonances_9_count
 resonances_9_count_SOURCES = resonances_9_count.f90
 resonances_9.run: resonances_9_count
 
 noinst_PROGRAMS += resonances_10_count
 resonances_10_count_SOURCES = resonances_10_count.f90
 resonances_10.run: resonances_10_count
 
 noinst_PROGRAMS += resonances_11_count
 resonances_11_count_SOURCES = resonances_11_count.f90
 resonances_11.run: resonances_11_count
 
 noinst_PROGRAMS += epa_2_count
 epa_2_count_SOURCES = epa_2_count.f90
 epa_2.run: epa_2_count
 
 noinst_PROGRAMS += isr_epa_1_count
 isr_epa_1_count_SOURCES = isr_epa_1_count.f90
 isr_epa_1.run: isr_epa_1_count
 
 noinst_PROGRAMS += analyze_6_check
 analyze_6_check_SOURCES = analyze_6_check.f90
 analyze_6.run: analyze_6_check
 
 endif
 
 if HEPMC_AVAILABLE
 TESTS_SRC += $(hepmc_6_rd_SOURCES)
 noinst_PROGRAMS += hepmc_6_rd
 if HEPMC_IS_VERSION3
 hepmc_6_rd_SOURCES = hepmc3_6_rd.cpp
 else
 hepmc_6_rd_SOURCES = hepmc2_6_rd.cpp
 endif
 hepmc_6_rd_CXXFLAGS = $(HEPMC_INCLUDES) $(AM_CXXFLAGS)
 hepmc_6_rd_LDADD = $(LDFLAGS_HEPMC)
 hepmc_6.run: hepmc_6_rd
 endif
 
 if LCIO_AVAILABLE
 TESTS_SRC += $(lcio_rd_SOURCES)
 noinst_PROGRAMS += lcio_rd
 lcio_rd_SOURCES = lcio_rd.cpp
 lcio_rd_CXXFLAGS = $(LCIO_INCLUDES) $(AM_CXXFLAGS)
 lcio_rd_LDADD = $(LDFLAGS_LCIO)
 lcio_1.run: lcio_rd
 lcio_2.run: lcio_rd
 lcio_3.run: lcio_rd
 lcio_4.run: lcio_rd
 lcio_5.run: lcio_rd
 lcio_10.run: lcio_rd
 endif
 
 stdhep_4.run: stdhep_rd
 stdhep_5.run: stdhep_rd
 stdhep_6.run: stdhep_rd
 polarized_1.run: stdhep_rd
 tauola_1.run: stdhep_rd
 tauola_2.run: stdhep_rd
 stdhep_rd: $(top_builddir)/src/xdr/stdhep_rd
 	cp $< $@
 
 susyhit.in: $(top_builddir)/share/tests/functional_tests/susyhit.in
 	cp $< $@
 
 BUILT_SOURCES = \
     TESTFLAG  \
     HEPMC2_FLAG \
     HEPMC3_FLAG \
     LCIO_FLAG \
     FASTJET_FLAG \
     LHAPDF5_FLAG \
     LHAPDF6_FLAG \
     GAMELAN_FLAG \
     MPI_FLAG \
     EVENT_ANALYSIS_FLAG \
     OCAML_FLAG \
     PYTHIA6_FLAG \
     PYTHIA8_FLAG \
     OPENLOOPS_FLAG \
     RECOLA_FLAG \
     GZIP_FLAG \
     STATIC_FLAG \
     ref-output
 
 # If this file is found in the working directory, WHIZARD
 # will use the paths for the uninstalled version (source/build tree),
 # otherwise it uses the installed version
 TESTFLAG:
 	touch $@
 
 FASTJET_FLAG:
 if FASTJET_AVAILABLE
 	touch $@
 endif
 
 HEPMC2_FLAG:
 if HEPMC2_AVAILABLE
 	touch $@
 endif
 
 HEPMC3_FLAG:
 if HEPMC3_AVAILABLE
 	touch $@
 endif
 
 LCIO_FLAG:
 if LCIO_AVAILABLE
 	touch $@
 endif
 
 LHAPDF5_FLAG:
 if LHAPDF5_AVAILABLE
 	touch $@
 endif
 
 LHAPDF6_FLAG:
 if LHAPDF6_AVAILABLE
 	touch $@
 endif
 
 GAMELAN_FLAG:
 if MPOST_AVAILABLE
 	touch $@
 endif
 
 MPI_FLAG:
 if FC_USE_MPI
 	touch $@
 endif
 
 OCAML_FLAG:
 if OCAML_AVAILABLE
 	touch $@
 endif
 
 PYTHIA6_FLAG:
 if PYTHIA6_AVAILABLE
 	touch $@
 endif
 
 PYTHIA8_FLAG:
 if PYTHIA8_AVAILABLE
 	touch $@
 endif
 
 OPENLOOPS_FLAG:
 if OPENLOOPS_AVAILABLE
 	touch $@
 endif
 
 RECOLA_FLAG:
 if RECOLA_AVAILABLE
 	touch $@
 endif
 
 EVENT_ANALYSIS_FLAG:
 if EVENT_ANALYSIS_AVAILABLE
 	touch $@
 endif
 
 GZIP_FLAG:
 if GZIP_AVAILABLE
 	touch $@
 endif
 
 STATIC_FLAG:
 if STATIC_AVAILABLE
 	touch $@
 endif
 
 # The reference output files are in the source directory.  Copy them here.
 if FC_QUAD
 ref-output: $(top_srcdir)/share/tests/functional_tests/ref-output
 	mkdir -p ref-output
 	for f in $</*.ref; do cp $$f $@; done
 	for f in $</../ref-output-prec/*.ref; do cp $$f $@; done
 	for f in $</../ref-output-quad/*.ref; do cp $$f $@; done
 else
 if FC_EXT
 ref-output: $(top_srcdir)/share/tests/functional_tests/ref-output
 	mkdir -p ref-output
 	for f in $</*.ref; do cp $$f $@; done
 	for f in $</../ref-output-prec/*.ref; do cp $$f $@; done
 	for f in $</../ref-output-ext/*.ref; do cp $$f $@; done
 else
 ref-output: $(top_srcdir)/share/tests/functional_tests/ref-output
 	mkdir -p ref-output
 	for f in $</*.ref; do cp $$f $@; done
 	for f in $</../ref-output-double/*.ref; do cp $$f $@; done
 endif
 endif
 
 ## installcheck runs the test scripts with the TESTFLAG removed.
 installcheck-local: notestflag check-am
 notestflag:
 	rm -f TESTFLAG
 .PHONY: notestflag
 
 ### Remove DWARF debug information on MAC OS X
 clean-macosx:
 	-rm -rf hepmc_6_rd.dSYM
 	-rm -rf lcio_rd.dSYM
 	-rm -rf static_1.exe.dSYM
 	-rm -rf static_2.exe.dSYM
 .PHONY: clean-macosx
 
 ## Remove generated files
 clean-local: clean-macosx
 	rm -f gamelan.sty
 	rm -f TESTFLAG GAMELAN_FLAG MPI_FLAG RECOLA_FLAG
 	rm -f OCAML_FLAG OPENLOOPS_FLAG FASTJET_FLAG HEPMC2_FLAG HEPMC3_FLAG
 	rm -f LCIO_FLAG EVENT_ANALYSIS_FLAG PYTHIA6_FLAG PYTHIA8_FLAG 
 	rm -f LHAPDF5_FLAG LHAPDF6_FLAG 
 	rm -f GZIP_FLAG STATIC_FLAG static_1.exe static_2.exe
 	rm -f *.run *.log slha_test.out *_check.out
 	rm -f core* stdhep_rd
 	rm -f *.f90 *.f90.in *.c *.$(FC_MODULE_EXT) *.o *.la
 	rm -f *_count.out
 	rm -f *.makefile
 	rm -f *.grid
 	rm -rf err-output
 	rm -rf ref-output
 	rm -f *.sin *.hbc *_fks_regions.out
 	rm -f *.olc *.olp *.olp_parameters output.rcl
 	rm -f *.phs *.vg *.vg2 *.vgx2 *.pg *.vgb *.evt *.evx *.lhe *.hepmc *.dat *.debug *.fds
 	rm -f *.tmp *.hepevt *.hepevt.verb *.lha *.lha.verb *.slcio
 	rm -f prc_omega_diags_1_p_i1_diags.out prc_omega_diags_1_p_i1_diags.toc
 	rm -rf pack_1.1 pack_1.2 pack_1.3 pack_1.4
 	rm -rf pack_1.1.tgz pack_1.2.tgz pack_1.3.tgz pack_1.4.tgz
 	rm -f *.hep *.up.hep *.[1-9] *.[1-9][0-9] *.[1-9][0-9][0-9] 
 	rm -f *.tex *.mp *.mpx *.t[1-9] *.t[1-9][0-9] *.t[1-9][0-9][0-9] 
 	rm -f *.ltp *.aux *.dvi *.ps *.pdf so_test.*
 	rm -f *.tbl sps1ap_decays.slha bar structure_6[a-b].out 
 	rm -f slhaspectrum.in suspect2.out suspect2_lha.out 
 	rm -f susyhit.in susyhit_slha.out suspect2_lha.in
 	rm -rf job_id_3_x.8001 job_id_4_x.8001
 	rm -rf ufo_1_SM ufo_2_SM ufo_3_models ufo_4_models
 	rm -f ufo_1_SM.ufo.mdl ufo_2_SM.ufo.mdl
 	rm -f ufo_3_SM.ufo.mdl ufo_4_SM.ufo.mdl
 	rm -f *.$(WT_OMEGA_CACHE_SUFFIX)
 	rm -rf output_cll
 	rm -rf *.dSYM
 if FC_SUBMODULES
 	rm -f *.smod
 endif
 
 ## Remove backup files
 maintainer-clean-local: maintainer-clean-fc
 	-rm -f *~
 .PHONY: maintainer-clean-local
Index: trunk/ChangeLog
===================================================================
--- trunk/ChangeLog	(revision 8346)
+++ trunk/ChangeLog	(revision 8347)
@@ -1,1953 +1,1954 @@
 ChangeLog -- Summary of changes to the WHIZARD package
 
 Use svn log to see detailed changes.
 
 	Version 2.8.3
 
 2020-01-09
 	RELEASE: version 2.8.3
 
 2019-11-19
 	Bug fix: resonance histories now work also with UFO models
 	Fix in numerical precision of ASCII VAMP2 grids
+	Allow quoted -e argument, implemented -f option
 
 2019-11-06
 	Add squared matrix elements to the LCIO event header
 
 2019-11-05
 	Do not include RNG state in MD5 sum for CIRCE1/2
 
 2019-11-04
 	Full CIRCE2 ILC 250 and 500 GeV beam spectra added
 	Minor update on LCIO event header information
 
 2019-10-30
 	NLO QCD for final states completed
 	When using Openloops, v2.1.1+ mandatory
 
 2019-10-25
 	Binary grid files for VAMP2 integrator
 
 ##################################################################
 
 2019-10-24
 	RELEASE: version 2.8.2
 
 2019-10-20
 	Bug fix for HepMC linker flags
 
 2019-10-19
 	Support for spin-2 particles from UFO files
 
 2019-09-27
 	LCIO event format allows rescan and alternate weights
 
 2019-09-24
 	Compatibility fix for OCaml v4.08.0+
 
 ##################################################################
 
 2019-09-21
 	RELEASE: version 2.8.1
 
 2019-09-19
 	Carriage return characters in UFO models can be parsed
 	Mathematica symbols in UFO models possible
 	Unused/undefined parameters in UFO models handled
 
 2019-09-13
 	New extended NLO test suite for ee and pp processes
 
 2019-09-09
 	Photon isolation (separation of perturbative and fragmentation
 	   part a la Frixione)
 
 2019-09-05
 	Major progress on NLO QCD for hadron collisions:
 	- correctly assign flavor structures for alpha regions
 	- fix crossing of particles for initial state splittings
 	- correct assignment for PDF factors for real subtractions
 	- fix kinematics for collinear splittings
 	- bug fix for integrated virtual subtraction terms
 
 2019-09-03
 	b and c jet selection in cuts and analysis
 
 2019-08-27
 	Support for Intel MPI
 
 2019-08-20
 	Complete (preliminary) HepMC3 support (incl.
 	   backwards HepMC2 write/read mode)
 
 2019-08-08
 	Bug fix: handle carriage returns in UFO files (non-Unix OS)
 
 ##################################################################
 
 2019-08-07
 	RELEASE: version 2.8.0
 
 2019-07-31
 	Complete WHIZARD UFO interface:
 	- general Lorentz structures
 	- matrix element support for general color factors
 	- missing features: Majorana fermions and SLHA
 
 2019-07-20
 	Make WHIZARD compatible with OCaml 4.08.0+
 
 2019-07-19
 	Fix version testing for LHAPDF 6.2.3 and newer
 	Minimal required OCaml version is now 4.02.3.
 
 2019-04-18
 	Correctly generate ordered FKS tuples for alpha regions
 	   from all possible underlying Born processes
 
 2019-04-08
 	Extended O'Mega/Recola matrix element test suite
 
 2019-03-29
 	Correct identical particle symmetry factors for FKS subtraction
 
 2019-03-28
 	Correct assertion of spin-correlated matrix
 	   elements for hadron collisions
 
 2019-03-27
 	Bug fix for cut-off parameter delta_i for
 	   collinear plus/minus regions
 
 ##################################################################
 
 2019-03-27
 	RELEASE: version 2.7.1
 
 2019-02-19
 	Further infrastructure for HepMC3 interface (v3.01.00)
 
 2019-02-07
 	Explicit configure option for using debugging options
 	Bug fix for performance by removing unnecessary debug operations
 
 2019-01-29
 	Bug fix for DGLAP remnants with cut-off parameter delta_i
 
 2019-01-24
 	Radiative decay neu2 -> neu1 A added to MSSM_Hgg model
 
 ##################################################################
 
 2019-01-21
 	RELEASE: version 2.7.0
 
 2018-12-18
 	Support RECOLA for integrated und unintegrated subtractions
 
 2018-12-11
 	FCNC top-up sector in model SM_top_anom
 
 2018-12-05
 	Use libtirpc instead of SunRPC on Arch Linux etc.
 
 2018-11-30
 	Display rescaling factor for weighted event samples with cuts
 
 2018-11-29
 	Reintroduce check against different masses in flavor sums
 	Bug fix for wrong couplings in the Littlest Higgs model(s)
 
 2018-11-22
 	Bug fix for rescanning events with beam structure
 
 2018-11-09
 	Major refactoring of internal process data
 
 2018-11-02
 	PYTHIA8 interface
 
 2018-10-29
         Flat phase space parametrization with RAMBO (on diet) implemented
 
 2018-10-17
 	Revise extended test suite
 
 2018-09-27
 	Process container for RECOLA processes
 
 2018-09-15
 	Fixes by M. Berggren for PYTHIA6 interface
 
 2018-09-14
 	First fixes after HepForge modernization
 
 ##################################################################
 
 2018-08-23
 	RELEASE: version 2.6.4
 
 2018-08-09
 	Infrastructure to check colored subevents
 
 2018-07-10
 	Infrastructure for running WHIZARD in batch mode
 
 2018-07-04
 	MPI available from distribution tarball
 
 2018-06-03
 	Support Intel Fortran Compiler under MAC OS X
 
 2018-05-07
 	FKS slicing parameter delta_i (initial state) implementend
 
 2018-05-03
 	Refactor structure function assignment for NLO
 
 2018-05-02
 	FKS slicing parameter xi_cut, delta_0 implemented
 
 2018-04-20
 	Workspace subdirectory for process integration (grid/phs files)
 	Packing/unpacking of files at job end/start
 	Exporting integration results from scan loops
 
 2018-04-13
 	Extended QCD NLO test suite
 
 2018-04-09
 	Bug fix for Higgs Singlet Extension model
 
 2018-04-06
 	Workspace subdirectory for process generation and compilation
 	--job-id option for creating job-specific names
 
 2018-03-20
 	Bug fix for color flow matching in hadron collisions
 	   with identical initial state quarks
 
 2018-03-08
 	Structure functions quantum numbers correctly assigned for NLO
 
 2018-02-24
 	Configure setup includes 'pgfortran' and 'flang'
 
 2018-02-21
 	Include spin-correlated matrix elements in interactions
 
 2018-02-15
 	Separate module for QED ISR structure functions
 
 ##################################################################
 
 2018-02-10
 	RELEASE: version 2.6.3
 
 2018-02-08
 	Improvements in memory management for PS generation
 
 2018-01-31
 	Partial refactoring: quantum number assigment NLO
 	Initial-state QCD splittings for hadron collisions
 
 2018-01-25
 	Bug fix for weighted events with VAMP2
 
 2018-01-17
 	Generalized interface for Recola versions 1.3+  and 2.1+
 
 2018-01-15
 	Channel equivalences also for VAMP2 integrator
 
 2018-01-12
 	Fix for OCaml compiler 4.06 (and newer)
 
 2017-12-19
 	RECOLA matrix elements with flavor sums can be integrated
 
 2017-12-18
 	Bug fix for segmentation fault in empty resonance histories
 
 2017-12-16
 	Fixing a bug in PYTHIA6 PYHEPC routine by omitting CMShowers
 	  from transferral between PYTHIA and WHIZARD event records
 
 2017-12-15
 	Event index for multiple processes in event file correct
 
 ##################################################################
 
 2017-12-13
 	RELEASE: version 2.6.2
 
 2017-12-07
 	User can set offset in event numbers
 
 2017-11-29
 	Possibility to have more than one RECOLA process in one file
 
 2017-11-23
 	Transversal/mixed (and unitarized) dim-8 operators
 
 2017-11-16
 	epa_q_max replaces epa_e_max (trivial factor 2)
 
 2017-11-15
 	O'Mega matrix element compilation silent now
 
 2017-11-14
 	Complete expanded P-wave form factor for top threshold
 
 2017-11-10
 	Incoming particles can be accessed in SINDARIN
 
 2017-11-08
 	Improved handling of resonance insertion, additional parameters
 
 2017-11-04
 	Added Higgs-electron coupling (SM_Higgs)
 
 ##################################################################
 
 2017-11-03
 	RELEASE: version 2.6.1
 
 2017-10-20
 	More than 5 NLO components possible at same time
 
 2017-10-19
 	Gaussian cutoff for shower resonance matching
 
 2017-10-12
 	Alternative (more efficient) method to generate
 	   phase space file
 
 2017-10-11
 	Bug fix for shower resonance histories for processes
 	   with multiple components
 
 2017-09-25
 	Bugfix for process libraries in shower resonance histories
 
 2017-09-21
 	Correctly generate pT distribution for EPA remnants
 
 2017-09-20
 	Set branching ratios for unstable particles also by hand
 
 2017-09-14
 	Correctly generate pT distribution for ISR photons
 
 ##################################################################
 
 2017-09-08
 	RELEASE: version 2.6.0
 
 2017-09-05
 	Bug fix for initial state NLO QCD flavor structures
 	Real and virtual NLO QCD hadron collider processes
 	   work with internal interactions
 
 2017-09-04
 	Fully validated MPI integration and event generation
 
 2017-09-01
 	Resonance histories for shower: full support
 	Bug fix in O'Mega model constraints
 	O'Mega allows to output a parsable form of the DAG
 
 2017-08-24
 	Resonance histories in events for transferral
 	   to parton shower (e.g. in ee -> jjjj)
 
 2017-08-01
 	Alpha version of HepMC v3 interface
 	   (not yet really functional)
 
 2017-07-31
 	Beta version for RECOLA OLP support
 
 2017-07-06
 	Radiation generator fix for LHC processes
 
 2017-06-30
 	Fix bug for NLO with structure
 	   functions and/or polarization
 
 2017-06-23
 	Collinear limit for QED corrections works
 
 2017-06-17
 	POWHEG grids generated already during integration
 
 2017-06-12
 	Soft limit for QED corrections works
 
 2017-05-16
 	Beta version of full MPI parallelization (VAMP2)
 	Check consistency of POWHEG grid files
 	Logfile config-summary.log for configure summary
 
 2017-05-12
 	Allow polarization in top threshold
 
 2017-05-09
 	Minimal demand automake 1.12.2
 	Silent rules for make procedures
 
 2017-05-07
 	Major fix for POWHEG damping
 	Correctly initialize FKS ISR phasespace
 
 ##################################################################
 
 2017-05-06
 	RELEASE: version 2.5.0
 
 2017-05-05
 	Full UFO support (SM-like models)
 	Fixed-beam ISR FKS phase space
 
 2017-04-26
 	QED splittings in radiation generator
 
 2017-04-10
 	Retire deprecated O'Mega vertex cache files
 
 ##################################################################
 
 2017-03-24
 	RELEASE: version 2.4.1
 
 2017-03-16
 	Distinguish resonance charge in phase space channels
 	Keep track of resonance histories in phase space
 	Complex mass scheme default for OpenLoops amplitudes
 
 2017-03-13
 	Fix helicities for polarized OpenLoops calculations
 
 2017-03-09
 	Possibility to advance RNG state in rng_stream
 
 2017-03-04
 	General setup for partitioning real emission
 	   phase space
 
 2017-03-06
 	Bugfix on rescan command for converting event files
 
 2017-02-27
 	Alternative multi-channel VEGAS implementation
 	   VAMP2: serial backbone for MPI setup
 	Smoothstep top threshold matching
 
 2017-02-25
 	Single-beam structure function with
 	   s-channel mapping supported
 	Safeguard against invalid process libraries
 
 2017-02-16
 	Radiation generator for photon emission
 
 2017-02-10
 	Fixes for NLO QCD processes (color correlations)
 
 2017-01-16
 	LCIO variable takes precedence over LCIO_DIR
 
 2017-01-13
 	Alternative random number generator
 	   rng_stream (cf. L'Ecuyer et al.)
 
 2017-01-01
 	Fix for multi-flavor BLHA tree
 	   matrix elements
 
 2016-12-31
 	Grid path option for VAMP grids
 
 2016-12-28
 	Alpha version of Recola OLP support
 
 2016-12-27
 	Dalitz plots for FKS phase space
 
 2016-12-14
 	NLO multi-flavor events possible
 
 2016-12-09
 	LCIO event header information added
 
 2016-12-02
 	Alpha version of RECOLA interface
 	Bugfix for generator status in LCIO
 
 ##################################################################
 
 2016-11-28
 	RELEASE: version 2.4.0
 
 2016-11-24
 	Bugfix for OpenLoops interface: EW scheme
 	   is set by WHIZARD
 	Bugfixes for top threshold implementation
 
 2016-11-11
 	Refactoring of dispatching
 
 2016-10-18
 	Bug fix for LCIO output
 
 2016-10-10
 	First implementation for collinear soft terms
 
 2016-10-06
 	First full WHIZARD models from UFO files
 
 2016-10-05
 	WHIZARD does not support legacy gcc 4.7.4 any longer
 
 2016-09-30
 	Major refactoring of process core and NLO components
 
 2016-09-23
 	WHIZARD homogeneous entity: discarding subconfigures
 	  for CIRCE1/2, O'Mega, VAMP subpackages; these are
 	  reconstructable by script projectors
 
 2016-09-06
 	Introduce main configure summary
 
 2016-08-26
 	Fix memory leak in event generation
 
 ##################################################################
 
 2016-08-25
 	RELEASE: version 2.3.1
 
 2016-08-19
 	Bug fix for EW-scheme dependence of gluino propagators
 
 2016-08-01
 	Beta version of complex mass scheme support
 
 2016-07-26
 	Fix bug in POWHEG damping for the matching
 
 ##################################################################
 
 2016-07-21
 	RELEASE: version 2.3.0
 
 2016-07-20
 	UFO file support (alpha version) in O'Mega
 
 2016-07-13
 	New (more) stable of WHIZARD GUI
 	Support for EW schemes for OpenLoops
 	Factorized NLO top decays for threshold model
 
 2016-06-15
 	Passing factorization scale to PYTHIA6
 	Adding charge and neutral observables
 
 2016-06-14
 	Correcting angular distribution/tweaked kinematics in
 	   non-collinear structure functions splittings
 
 2016-05-10
 	Include (Fortran) TAUOLA/PHOTOS for tau decays via PYTHIA6
 	   (backwards validation of LC CDR/TDR samples)
 
 2016-04-27
 	Within OpenLoops virtuals: support for Collier library
 
 2016-04-25
 	O'Mega vertex tables only loaded at first usage
 
 2016-04-21
 	New CJ15 PDF parameterizations added
 
 2016-04-21
 	Support for hadron collisions at NLO QCD
 
 2016-04-05
 	Support for different (parameter) schemes in model files
 
 2016-03-31
 	Correct transferral of lifetime/vertex from PYTHIA/TAUOLA
 	  into the event record
 
 2016-03-21
 	New internal implementation of polarization
 	  via Bloch vectors, remove pointer constructions
 
 2016-03-13
 	Extension of cascade syntax for processes:
 	  exclude propagators/vertices etc. possible
 
 2016-02-24
 	Full support for OpenLoops QCD NLO matrix
 	  elements, inclusion in test suite
 
 2016-02-12
 	Substantial progress on QCD NLO support
 
 2016-02-02
 	Automated resonance mapping for FKS subtraction
 
 2015-12-17
 	New BSM model WZW for diphoton resonances
 
 ##################################################################
 
 2015-11-22
 	RELEASE: version 2.2.8
 
 2015-11-21
 	Bugfix for fixed-order NLO events
 
 2015-11-20
 	Anomalous FCNC top-charm vertices
 
 2015-11-19
 	StdHEP output via HEPEVT/HEPEV4 supported
 
 2015-11-18
 	Full set of electroweak dim-6 operators included
 
 2015-10-22
 	Polarized one-loop amplitudes supported
 
 2015-10-21
 	Fixes for event formats for showered events
 
 2015-10-14
 	Callback mechanism for event output
 
 2015-09-22
 	Bypass matrix elements in pure event sample rescans
 	StdHep frozen final version v5.06.01 included internally
 
 2015-09-21
 	configure option --with-precision to
 	  demand 64bit, 80bit, or 128bit Fortran
 	  and bind C precision types
 
 2015-09-07
 	More extensive tests of NLO
 	   infrastructure and POWHEG matching
 
 2015-09-01
 	NLO decay infrastructure
 	User-defined squared matrix elements
 	Inclusive FastJet algorithm plugin
 	Numerical improvement for small boosts
 
 ##################################################################
 
 2015-08-11
 	RELEASE: version 2.2.7
 
 2015-08-10
 	Infrastructure for damped POWHEG
 	Massive emitters in POWHEG
 	Born matrix elements via BLHA
 	GoSam filters via SINDARIN
 	Minor running coupling bug fixes
 	Fixed-order NLO events
 
 2015-08-06
 	CT14 PDFs included (LO, NLO, NNLL)
 
 2015-07-07
 	Revalidation of ILC WHIZARD-PYTHIA event chain
 	Extended test suite for showered events
 	Alpha version of massive FSR for POWHEG
 
 2015-06-09
 	Fix memory leak in interaction for long cascades
 	Catch mismatch between beam definition and CIRCE2 spectrum
 
 2015-06-08
 	Automated POWHEG matching: beta version
 	Infrastructure for GKS matching
 	Alpha version of fixed-order NLO events
 	CIRCE2 polarization averaged spectra with
 	   explicitly polarized beams
 
 2015-05-12
 	Abstract matching type: OO structure for matching/merging
 
 2015-05-07
 	Bug fix in event record WHIZARD-PYTHIA6 transferral
 	Gaussian beam spectra for lepton colliders
 
 ##################################################################
 
 2015-05-02
 	RELEASE: version 2.2.6
 
 2015-05-01
 	Models for (unitarized) tensor resonances in VBS
 
 2015-04-28
 	Bug fix in channel weights for event generation.
 
 2015-04-18
 	Improved event record transfer WHIZARD/PYTHIA6
 
 2015-03-19
 	POWHEG matching: alpha version
 
 ##################################################################
 
 2015-02-27
 	RELEASE: version 2.2.5
 
 2015-02-26
 	Abstract types for quantum numbers
 
 2015-02-25
 	Read-in of StdHEP events, self-tests
 
 2015-02-22
 	Bugfix for mother-daughter relations in
 	   showered/hadronized events
 
 2015-02-20
 	Projection on polarization in intermediate states
 
 2015-02-13
 	Correct treatment of beam remnants in
 	   event formats (also LC remnants)
 
 ##################################################################
 
 2015-02-06
 	RELEASE: version 2.2.4
 
 2015-02-06
 	Bugfix in event output
 
 2015-02-05
 	LCIO event format supported
 
 2015-01-30
 	Including state matrices in WHIZARD's internal IO
 	Versioning for WHIZARD's internal IO
 	Libtool update from 2.4.3 to 2.4.5
 	LCIO event output (beta version)
 
 2015-01-27
 	Progress on NLO integration
 	Fixing a bug for multiple processes in a single
 	   event file when using beam event files
 
 2015-01-19
 	Bug fix for spin correlations evaluated in the rest
 	   frame of the mother particle
 
 2015-01-17
 	Regression fix for statically linked processes
 	   from SARAH and FeynRules
 
 2015-01-10
 	NLO: massive FKS emitters supported (experimental)
 
 2015-01-06
 	MMHT2014 PDF sets included
 
 2015-01-05
 	Handling mass degeneracies in auto_decays
 
 2014-12-19
 	Fixing bug in rescan of event files
 
 ##################################################################
 
 2014-11-30
 	RELEASE: version 2.2.3
 
 2014-11-29
 	Beta version of LO continuum/NLL-threshold
 	matched top threshold model for e+e- physics
 
 2014-11-28
 	More internal refactoring: disentanglement of module
 	   dependencies
 
 2014-11-21
 	OVM: O'Mega Virtual Machine, bytecode instructions
 	   instead of compiled Fortran code
 
 2014-11-01
 	Higgs Singlet extension model included
 
 2014-10-18
 	Internal restructuring of code; half-way
 	  WHIZARD main code file disassembled
 
 2014-07-09
 	Alpha version of NLO infrastructure
 
 ##################################################################
 
 2014-07-06
 	RELEASE: version 2.2.2
 
 2014-07-05
 	CIRCE2: correlated LC beam spectra and
 	  GuineaPig Interface to LC machine parameters
 
 2014-07-01
 	Reading LHEF for decayed/factorized/showered/
 	   hadronized events
 
 2014-06-25
 	Configure support for GoSAM/Ninja/Form/QGraf
 
 2014-06-22
 	LHAPDF6 interface
 
 2014-06-18
 	Module for automatic generation of
 	  radiation and loop infrastructure code
 
 2014-06-11
 	Improved internal directory structure
 
 ##################################################################
 
 2014-06-03
 	RELEASE: version 2.2.1
 
 2014-05-30
 	Extensions of internal PDG arrays
 
 2014-05-26
 	FastJet interface
 
 2014-05-24
 	CJ12 PDFs included
 
 2014-05-20
 	Regression fix for external models (via SARAH
 	    or FeynRules)
 
 ##################################################################
 
 2014-05-18
 	RELEASE: version 2.2.0
 
 2014-04-11
 	Multiple components: inclusive process definitions,
 	   syntax: process A + B + ...
 
 2014-03-13
 	Improved PS mappings for e+e- ISR
 	ILC TDR and CLIC spectra included in CIRCE1
 
 2014-02-23
 	New models: AltH w\ Higgs for exclusion purposes,
 	  SM_rx for Dim 6-/Dim-8 operators, SSC for
 	  general strong interactions (w/ Higgs), and
 	  NoH_rx (w\ Higgs)
 
 2014-02-14
 	Improved s-channel mapping, new on-shell
 	  production mapping (e.g. Drell-Yan)
 
 2014-02-03
 	PRE-RELEASE: version 2.2.0_beta
 
 2014-01-26
 	O'Mega: Feynman diagram generation possible (again)
 
 2013-12-16
 	HOPPET interface for b parton matching
 
 2013-11-15
 	PRE-RELEASE: version 2.2.0_alpha-4
 
 2013-10-27
 	LHEF standards 1.0/2.0/3.0 implemented
 
 2013-10-15
 	PRE-RELEASE: version 2.2.0_alpha-3
 
 2013-10-02
 	PRE-RELEASE: version 2.2.0_alpha-2
 
 2013-09-25
 	PRE-RELEASE: version 2.2.0_alpha-1
 
 2013-09-12
 	PRE-RELEASE: version 2.2.0_alpha
 
 2013-09-03
 	General 2HDM implemented
 
 2013-08-18
 	Rescanning/recalculating events
 
 2013-06-07
 	Reconstruction of complete event
 	  from 4-momenta possible
 
 2013-05-06
 	Process library stacks
 
 2013-05-02
 	Process stacks
 
 2013-04-29
 	Single-particle phase space module
 
 2013-04-26
 	Abstract interface for random
 	  number generator
 
 2013-04-24
 	More object-orientation on modules
 	Midpoint-rule integrator
 
 2013-04-05
 	Object-oriented integration and
 	  event generation
 
 2013-03-12
 	Processes recasted object-oriented:
 	  MEs, scales, structure functions
 	First infrastructure for general Lorentz
 	  structures
 
 2013-01-17
 	Object-orientated reworking of library and
 	   process core, more variable internal structure,
 	   unit tests
 
 2012-12-14
 	Update Pythia version to 6.4.27
 
 2012-12-04
 	Fix the phase in HAZ vertices
 
 2012-11-21
 	First O'Mega unit tests, some infrastructure
 
 2012-11-13
 	Bugfix in anom. HVV Lorentz structures
 
 ##################################################################
 
 2012-09-18
 	RELEASE: version 2.1.1
 
 2012-09-11
 	Model MSSM_Hgg with Hgg and HAA vertices
 
 2012-09-10
 	First version of implementation of multiple
 	   interactions in WHIZARD
 
 2012-09-05
 	Infrastructure for internal CKKW matching
 
 2012-09-02
 	C, C++, Python API
 
 2012-07-19
 	Fixing particle numbering in HepMC format
 
 ##################################################################
 
 2012-06-15
 	RELEASE: version 2.1.0
 
 2012-06-14
 	Analytical and kT-ordered shower officially
 	  released
 	PYTHIA interface officially released
 
 2012-05-09
 	Intrisince PDFs can be used for showering
 
 2012-05-04
 	Anomalous Higgs couplings a la hep-ph/9902321
 
 ##################################################################
 
 2012-03-19
 	RELEASE: version 2.0.7
 
 2012-03-15
 	Run IDs are available now
 	More event variables in analysis
 	Modified raw event format (compatibility mode exists)
 
 2012-03-12
 	Bugfix in decay-integration order
 	MLM matching steered completely internally now
 
 2012-03-09
 	Special phase space mapping for narrow resonances
 	  decaying to 4-particle final states with far off-shell
 	  intermediate states
 	Running alphas from PDF collaborations with
 	  builtin PDFs
 
 2012-02-16
 	Bug fix in cascades decay infrastructure
 
 2012-02-04
 	WHIZARD documentation compatible with TeXLive 2011
 
 2012-02-01
 	Bug fix in FeynRules interface with --prefix flag
 
 2012-01-29
 	Bug fix with name clash of O'Mega variable names
 
 2012-01-27
 	Update internal PYTHIA to version 6.4.26
 	Bug fix in LHEF output
 
 2012-01-21
 	Catching stricter automake 1.11.2 rules
 
 2011-12-23
 	Bug fix in decay cascade setup
 
 2011-12-20
 	Bug fix in helicity selection rules
 
 2011-12-16
 	Accuracy goal reimplemented
 
 2011-12-14
 	WHIZARD compatible with TeXLive 2011
 
 2011-12-09
 	Option --user-target added
 
 ##################################################################
 
 2011-12-07
 	RELEASE: version 2.0.6
 
 2011-12-07
 	Bug fixes in SM_top_anom
 	Added missing entries to HepMC format
 
 2011-12-06
 	Allow to pass options to O'Mega
 	Bug fix for HEPEVT block for showered/hadronized events
 
 2011-12-01
 	Reenabled user plug-in for external code for
 	   cuts, structure functions, routines etc.
 
 2011-11-29
 	Changed model SM_Higgs for Higgs phenomenology
 
 2011-11-25
 	Supporting a Y, (B-L) Z' model
 
 2011-11-23
 	Make WHIZARD compatible for MAC OS X Lion/XCode 4
 
 2011-09-25
 	WHIZARD paper published: Eur.Phys.J. C71 (2011) 1742
 
 2011-08-16
 	Model SM_QCD: QCD with one EW insertion
 
 2011-07-19
 	Explicit output channel for dvips avoids printing
 
 2011-07-10
 	Test suite for WHIZARD unit tests
 
 2011-07-01
 	Commands for matrix element tests
 	More OpenMP parallelization of kinematics
 	Added unit tests
 
 2011-06-23
 	Conversion of CIRCE2 from F77 to F90, major
 	  clean-up
 
 2011-06-14
 	Conversion of CIRCE1 from F77 to F90
 
 2011-06-10
 	OpenMP parallelization of channel kinematics
 		(by Matthias Trudewind)
 
 2011-05-31
 	RELEASE: version 1.97
 
 2011-05-24
 	Minor bug fixes: update grids and elsif statement.
 
 ##################################################################
 
 2011-05-10
 	RELEASE: version 2.0.5
 
 2011-05-09
 	Fixed bug in final state flavor sums
 	Minor improvements on phase-space setup
 
 2011-05-05
 	Minor bug fixes
 
 2011-04-15
 	WHIZARD as a precompiled 64-bit binary available
 
 2011-04-06
 	Wall clock instead of cpu time for time estimates
 
 2011-04-05
 	Major improvement on the phase space setup
 
 2011-04-02
 	OpenMP parallelization for helicity loop in O'Mega
 	   matrix elements
 
 2011-03-31
 	Tools for relocating WHIZARD and use in batch
 	environments
 
 2011-03-29
 	Completely static builds possible, profiling options
 
 2011-03-28
 	Visualization of integration history
 
 2011-03-27
 	Fixed broken K-matrix implementation
 
 2011-03-23
 	Including the GAMELAN manual in the distribution
 
 2011-01-26
 	WHIZARD analysis can handle hadronized event files
 
 2011-01-17
 	MSTW2008 and CT10 PDF sets included
 
 2010-12-23
 	Inclusion of NMSSM with Hgg couplings
 
 2010-12-21
 	Advanced options for integration passes
 
 2010-11-16
 	WHIZARD supports CTEQ6 and possibly other PDFs
 	directly; data files included in the distribution
 
 ##################################################################
 
 2010-10-26
 	RELEASE: version 2.0.4
 
 2010-10-06
 	Bug fix in MSSM implementation
 
 2010-10-01
 	Update to libtool 2.4
 
 2010-09-29
 	Support for anomalous top couplings (form factors etc.)
 	Bug fix for running gauge Yukawa SUSY couplings
 
 2010-09-28
 	RELEASE: version 1.96
 
 2010-09-21
 	Beam remnants and pT spectra for lepton collider re-enabled
 	Restructuring subevt class
 
 2010-09-16
 	Shower and matching are disabled by default
 	PYTHIA as a conditional on these two options
 
 2010-09-14
 	Possibility to read in beam spectra re-enabled (e.g. Guinea
 	   Pig)
 
 2010-09-13
 	Energy scan as (pseudo-) structure functions re-implemented
 
 2010-09-10
 	CIRCE2 included again in WHIZARD 2 and validated
 
 2010-09-02
 	Re-implementation of asymmetric beam energies and collision
 	  angles, e-p collisions work, inclusion of a HERA DIS test
 	  case
 
 ##################################################################
 
 2010-10-18
 	RELEASE: version 2.0.3
 
 2010-08-08
 	Bug in CP-violating anomalous triple TGCs fixed
 
 2010-08-06
 	Solving backwards compatibility problem with O'Caml 3.12.0
 
 2010-07-12
 	Conserved quantum numbers speed up O'Mega code generation
 
 2010-07-07
 	Attaching full ISR/FSR parton shower and MPI/ISR
 	   module
 	Added SM model containing Hgg, HAA, HAZ vertices
 
 2010-07-02
 	Matching output available as LHEF and STDHEP
 
 2010-06-30
 	Various bug fixes, missing files, typos
 
 2010-06-26
 	CIRCE1 completely re-enabled
 	Chaining structure functions supported
 
 2010-06-25
 	Partial support for conserved quantum numbers in
 	   O'Mega
 
 2010-06-21
 	Major upgrade of the graphics package: error bars,
 	   smarter SINDARIN steering, documentation, and all that...
 
 2010-06-17
 	MLM matching with PYTHIA shower included
 
 2010-06-16
 	Added full CIRCE1 and CIRCE2 versions including
 	full documentation and miscellanea to the trunk
 
 2010-06-12
 	User file management supported, improved variable
 	and command structure
 
 2010-05-24
 	Improved handling of variables in local command lists
 
 2010-05-20
 	PYTHIA interface re-enabled
 
 2010-05-19
 	ASCII file formats for interfacing ROOT and gnuplot in
 	   data analysis
 
 ##################################################################
 
 2010-05-18
 	RELEASE: version 2.0.2
 
 2010-05-14
 	Reimplementation of visualization of phase space
 	   channels
 	Minor bug fixes
 
 2010-05-12
 	Improved phase space - elimination of redundancies
 
 2010-05-08
 	Interface for polarization completed: polarized beams etc.
 
 2010-05-06
 	Full quantum numbers appear in process log
 	Integration results are usable as user variables
 	Communication with external programs
 
 2010-05-05
 	Split module commands into commands, integration,
 	   simulation modules
 
 2010-05-04
 	FSR+ISR for the first time connected to the WHIZARD 2 core
 
 ##################################################################
 
 2010-04-25
 	RELEASE: version 2.0.1
 
 2010-04-23
 	Automatic compile and integrate if simulate is called
 	Minor bug fixes in O'Mega
 
 2010-04-21
 	Checkpointing for event generation
 	Flush statements to use WHIZARD inside a pipe
 
 2010-04-20
 	Reimplementation of signal handling in WGIZARD 2.0
 
 2010-04-19
 	VAMP is now a separately configurable and installable unit of
 	   WHIZARD, included VAMP self-checks
 	Support again compilation in quadruple precision
 
 2010-04-06
 	Allow for logarithmic plots in GAMELAN, reimplement the
 	   possibility to set the number of bins
 
 2010-04-15
 	Improvement on time estimates for event generation
 
 ##################################################################
 
 2010-04-12
 	RELEASE: version 2.0.0
 
 2010-04-09
 	Per default, the code for the amplitudes is subdivided to allow
 	  faster compiler optimization
 	More advanced and unified and straightforward command language
 	  syntax
 	Final bug fixes
 
 2010-04-07
 	Improvement on SINDARIN syntax; printf, sprintf function
 	  thorugh a C interface
 
 2010-04-05
 	Colorizing DAGs instead of model vertices: speed boost
 	  in colored code generation
 
 2010-03-31
 	Generalized options for normalization of weighted and
 	  unweighted events
 	Grid and weight histories added again to log files
 	Weights can be used in analyses
 
 2010-03-28
 	Cascade decays completely implemented including color and
 	   spin correlations
 
 2010-03-07
 	Added new WHIZARD header with logo
 
 2010-03-05
 	Removed conflict in O'Mega amplitudes between flavour sums
 	   and cascades
 	StdHEP interface re-implemented
 
 2010-03-03
 	RELEASE: version 2.0.0rc3
 	Several bug fixes for preventing abuse in input files
 	OpenMP support for amplitudes
 	Reimplementation of WHIZARD 1 HEPEVT ASCII event formats
 	FeynRules interface successfully passed MSSM test
 
 2010-02-26
 	Eliminating ghost gluons from multi-gluon amplitudes
 
 2010-02-25
 	RELEASE: version 1.95
 	HEPEVT format from WHIZARD 1 re-implemented in WHIZARD 2
 
 2010-02-23
 	Running alpha_s implemented in the FeynRules interface
 
 2010-02-19
 	MSSM (semi-) automatized self-tests finalized
 
 2010-02-17
 	RELEASE: version 1.94
 
 2010-02-16
 	Closed memory corruption in WHIZARD 1
 	Fixed problems of old MadGraph and CompHep drivers
 	   with modern compilers
 	Uncolored vertex selection rules for colored amplitudes in
 	   O'Mega
 
 2010-02-15
 	Infrastructure for color correlation computation in O'Mega
 	   finished
 	Forbidden processes are warned about, but treated as non-fatal
 
 2010-02-14
 	Color correlation computation in O'Mega finalized
 
 2010-02-10
 	Improving phase space mappings for identical particles in
 	initial and final states
 	Introduction of more extended multi-line error message
 
 2010-02-08
 	First O'Caml code for computation of color correlations in
 	O'Mega
 
 2010-02-07
 	First MLM matching with e+ e- -> jets
 
 ##################################################################
 
 2010-02-06
 	RELEASE: version 2.0.0rc2
 
 2010-02-05
 	Reconsidered the Makefile structure and more extended tests
 	Catch a crash between WHIZARD and O'Mega for forbidden processes
 	Tensor products of arbitrary color structures in jet definitions
 
 2010-02-04
 	Color correlation computation in O'Mega finalized
 
 ##################################################################
 
 2010-02-03
 	RELEASE: version 2.0.0rc1
 
 ##################################################################
 
 2010-01-31
 	Reimplemented numerical helicity selection rules
 	Phase space functionality of version 1 restored and improved
 
 2009-12-05
 	NMSSM validated with FeynRules in WHIZARD 1 (Felix Braam)
 
 2009-12-04
 	RELEASE: version 2.0.0alpha
 
 ##################################################################
 
 2009-04-16
 	RELEASE: version 1.93
 
 2009-04-15
 	Clean-up of Makefiles and configure scripts
 	Reconfiguration of BSM model implementation
 	extended supersymmetric models
 
 2008-12-23
 	New model NMSSM	(Felix Braam)
 	SLHA2 added
 	Bug in LHAPDF interface fixed
 
 2008-08-16
 	Bug fixed in K matrix implementation
 	Gravitino option in the MSSM added
 
 2008-03-20
 	Improved color and flavor sums
 
 ##################################################################
 
 2008-03-12
 	RELEASE: version 1.92
 	LHEF (Les Houches Event File) format added
 	Fortran 2003 command-line interface (if supported by the compiler)
 	Automated interface to colored models
 	More bug fixes and workarounds for compiler compatibility
 
 ##################################################################
 
 2008-03-06
 	RELEASE: version 1.91
 	New model K-matrix (resonances and anom. couplings in WW scattering)
 	EWA spectrum
 	Energy-scan pseudo spectrum
 	Preliminary parton shower module (only from final-state quarks)
 	Cleanup and improvements of configure process
 	Improvements for O'Mega parameter files
 	Quadruple precision works again
 	More plotting options: lines, symbols, errors
 	Documentation with PDF bookmarks enabled
 	Various bug fixes
 
 2007-11-29
 	New model UED
 
 ##################################################################
 
 2007-11-23
 	RELEASE: version 1.90
 	O'Mega now part of the WHIZARD tree
 	Madgraph/CompHEP disabled by default (but still usable)
 	Support for LHAPDF (preliminary)
 	Added new models: SMZprime, SM_km, Template
 	Improved compiler recognition and compatibility
 	Minor bug fixes
 
 ##################################################################
 
 2006-06-15
 	RELEASE: version 1.51
 	Support for anomaly-type Higgs couplings (to gluon and photon/Z)
 	Support for spin 3/2 and spin 2
 	New models: Little Higgs (4 versions), toy models for extra dimensions
           and gravitinos
 	Fixes to the whizard.nw source documentation to run through LaTeX
 	Intel 9.0 bug workaround (deallocation of some arrays)
 
 2006-05-15
 	O'Mega RELEASE: version 0.11
 	merged JRR's O'Mega extensions
 
 ##################################################################
 
 2006-02-07
 	RELEASE: version 1.50
         To avoid confusion: Mention outdated manual example in BUGS file
         O'Mega becomes part of the WHIZARD generator
 
 2006-02-02   [bug fix update]
 	Bug fix: spurious error when writing event files for weighted events
 	Bug fix: 'r' option for omega produced garbage for some particle names
 	Workaround for ifort90 bug (crash when compiling whizard_event)
 	Workaround for ifort90 bug (crash when compiling hepevt_common)
 
 2006-01-27
 	Added process definition files for MSSM 2->2 processes
 	Included beam recoil for EPA (T.Barklow)
 	Updated STDHEP byte counts (for STDHEP 5.04.02)
 	Fixed STDHEP compatibility (avoid linking of incomplete .so libs)
 	Fixed issue with comphep requiring Xlibs on Opteron
 	Fixed issue with ifort 8.x on Opteron (compiling 'signal' interface)
 	Fixed color-flow code: was broken for omega with option 'c' and 'w'
 	Workaround hacks for g95 compatibility
 
 2005-11-07
 	O'Mega RELEASE: version 0.10
 	O'Mega, merged JRR's and WK's color hack for WHiZard
         O'Mega, EXPERIMENTAL: cache fusion tables (required for colors
 	  a la JRR/WK)
         O'Mega, make JRR's MSSM official
 
 ##################################################################
 
 2005-10-25
 	RELEASE: version 1.43
 	Minor fixes in MSSM couplings (Higgs/3rd gen squarks).
 	  This should be final, since the MSSM results agree now completely
           with Madgraph and Sherpa
 	User-defined lower and upper limits for split event file count
 	Allow for counters (events, bytes) exceeding $2^{31}$
 	Revised checksum treatment and implementation (now MD5)
         Bug fix: missing process energy scale in raw event file
 
 ##################################################################
 
 2005-09-30
 	RELEASE: version 1.42
 	Graphical display of integration history ('make history')
 	Allow for switching off signals even if supported (configure option)
 
 2005-09-29
 	Revised phase space generation code, in particular for flavor sums
 	Negative cut and histogram codes use initial beams instead of
 	  initial parton momenta.  This allows for computing, e.g., E_miss
 	Support constant-width and zero-width options for O'Mega
 	Width options now denoted by w:X (X=f,c,z).  f option obsolescent
 	Bug fix: colorized code: flipped indices could screw up result
 	Bug fix: O'Mega with 'c' and 'w:f' option together (still some problem)
 	Bug fix: dvips on systems where dvips defaults to lpr
 	Bug fix: integer overflow if too many events are requested
 
 2005-07-29
 	Allow for 2 -> 1 processes (if structure functions are on)
 
 2005-07-26
 	Fixed and expanded the 'test' matrix element:
 	  Unit matrix element with option 'u' / default: normalized phase space
 
 ##################################################################
 
 2005-07-15
 	RELEASE: version 1.41
 	Bug fix: no result for particle decay processes with width=0
 	Bug fix: line breaks in O'Mega files with color decomposition
 
 2005-06-02
 	New self-tests (make test-QED / test-QCD / test-SM)
 	  check lists of 2->2 processes
 	Bug fix: HELAS calling convention for wwwwxx and jwwwxx (4W-Vertex)
 
 2005-05-25
 	Revised Makefile structure
 	Eliminated obsolete references to ISAJET/SUSY (superseded by SLHA)
 
 2005-05-19
 	Support for color in O'Mega (using color flow decomposition)
 	New model QCD
 	Parameter file changes that correspond to replaced SM module in O'Mega
 	Bug fixes in MSSM (O'Mega) parameter file
 
 2005-05-18
 	New event file formats, useful for LHC applications:
           ATHENA and Les Houches Accord (external fragmentation)
         Naive (i.e., leading 1/N) color factor now implemented both for
           incoming and outgoing partons
 
 2005-01-26
 	include missing HELAS files for bundle
 	pgf90 compatibility issues [note: still internal error in pgf90]
 
 ##################################################################
 
 2004-12-13
 	RELEASE: version 1.40
 	compatibility fix: preprocessor marks in helas code now commented out
 	minor bug fix: format string in madgraph source
 
 2004-12-03
 	support for arbitray beam energies and directions
 	allow for pT kick in structure functions
 	bug fix: rounding error could result in zero cross section
 	  (compiler-dependent)
 
 2004-10-07
 	simulate decay processes
 	list fraction (of total width/cross section) instead of efficiency
           in process summary
 	new cut/analysis parameters AA, AAD, CTA: absolute polar angle
 
 2004-10-04
 	Replaced Madgraph I by Madgraph II.  Main improvement: model no
           longer hardcoded
 	introduced parameter reset_seed_each_process (useful for debugging)
         bug fix: color initialization for some processes was undefined
 
 2004-09-21
 	don't compile unix_args module if it is not required
 
 ##################################################################
 
 2004-09-20
 	RELEASE: version 1.30
 	g95 compatibility issues resolved
 	some (irrelevant) memory leaks closed
 	removed obsolete warning in circe1
 	manual update (essentially) finished
 
 2004-08-03
 	O'Mega RELEASE: version 0.9
 	O'Mega, src/trie.mli, src/trie.ml: make interface compatible with
           the O'Caml 3.08 library (remains compatible with older
           versions).  Implementation of unused functions still
           incomplete.
 
 2004-07-26
 	minor fixes and improvements in make process
 
 2004-06-29
 	workarounds for new Intel compiler bugs ...
 	no rebuild of madgraph/comphep executables after 'make clean'
 	bug fix in phase space routine:
           wrong energy for massive initial particles
         bug fix in (new) model interface: name checks for antiparticles
         pre-run checks for comphep improved
         ww-strong model file extended
         Model files particle name fixes, chep SM vertices included
 
 2004-06-22
 	O'Mega RELEASE: version 0.8
 	O'Mega MSSM: sign of W+/W-/A and W+/W-/Z couplings
 
 2004-05-05
 	Fixed bug in PDFLIB interface: p+pbar was initialized as p+p (ThO)
 	NAG compiler: set number of continuation lines to 200 as default
 	Extended format for cross section summary; appears now in whizard.out
 	Fixed 'bundle' feature
 
 2004-04-28
 	Fixed compatibility with revised O'Mega SM_ac model
 	Fixed problem with x=0 or x=1 when calling PDFLIB (ThO)
 	Fixed bug in comphep module: Vtb was overlooked
 
 ##################################################################
 
 2004-04-15
 	RELEASE: version 1.28
         Fixed bug: Color factor was missing for O'Mega processes with
           four quarks and more
         Manual partially updated
 
 2004-04-08
 	Support for grid files in binary format
 	New default value show_histories=F (reduce output file size)
 	Revised phase space switches: removed annihilation_lines,
 	  removed s_channel_resonance, changed meaning of
 	  extra_off_shell_lines, added show_deleted_channels
 	Bug fixed which lead to omission of some phase space channels
 	Color flow guessed only if requested by guess_color_flow
 
 2004-03-10
 	New model interface: Only one model name specified in whizard.prc
         All model-dependent files reside in conf/models (modellib removed)
 
 2004-03-03
 	Support for input/output in SUSY Les Houches Accord format
 	Split event files if requested
 	Support for overall time limit
 	Support for CIRCE and CIRCE2 generator mode
 	Support for reading beam events from file
 
 2004-02-05
 	Fixed compiler problems with Intel Fortran 7.1 and 8.0
 	Support for catching signals
 
 ##################################################################
 
 2003-08-06
 	RELEASE: version 1.27
 	User-defined PDF libraries as an alternative to the standard PDFLIB
 
 2003-07-23
 	Revised phase space module: improved mappings for massless particles,
 	  equivalences of phase space channels are exploited
 	Improved mapping for PDF (hadron colliders)
 	Madgraph module: increased max number of color flows from 250 to 1000
 
 ##################################################################
 
 2003-06-23
 	RELEASE: version 1.26
 	CIRCE2 support
 	Fixed problem with 'TC' integer kind [Intel compiler complained]
 
 2003-05-28
 	Support for drawing histograms of grids
 	Bug fixes for MSSM definitions
 
 ##################################################################
 
 2003-05-22
 	RELEASE: version 1.25
 	Experimental MSSM support with ISAJET interface
 	Improved capabilities of generating/analyzing weighted events
 	Optional drawing phase space diagrams using FeynMF
 
 ##################################################################
 
 2003-01-31
 	RELEASE: version 1.24
 	A few more fixes and workarounds (Intel and Lahey compiler)
 
 2003-01-15
 	Fixes and workarounds needed for WHIZARD to run with Intel compiler
 	Command-line option interface for the Lahey compiler
 
 	Bug fix: problem with reading whizard.phs
 
 ##################################################################
 
 2002-12-10
 	RELEASE: version 1.23
 
 	Command-line options (on some systems)
 
 	Allow for initial particles in the event record, ordered:
           [beams, initials] - [remnants] - outgoing partons
 
 	Support for PYTHIA 6.2: Les Houches external process interface
 	String pythia_parameters can be up to 1000 characters long
 	Select color flow states in (internal) analysis
 	Bug fix in color flow content of raw event files
 
 	Support for transversal polarization of fermion beams
 	Cut codes: PHI now for absolute azimuthal angle, DPHI for distance
 	'Test' matrix elements optionally respect polarization
 
 	User-defined code can be inserted for spectra, structure functions
           and fragmentation
 
 	Time limits can be specified for adaptation and simulation
 	User-defined file names and file directory
         Initial weights in input file no longer supported
 
         Bug fix in MadGraph (wave function counter could overflow)
 
 	Bug fix: Gamelan (graphical analysis) was not built if noweb absent
 
 ##################################################################
 
 2002-03-16
 	RELEASE: version 1.22
 	Allow for beam remnants in the event record
 
 2002-03-01
         Handling of aliases in whizard.prc fixed (aliases are whole tokens)
 
 2002-02-28
 	Optimized phase space handling routines
 	  (total execution time reduced by 20-60%, depending on process)
 
 ##################################################################
 
 2002-02-26
 	RELEASE: version 1.21
 	Fixed ISR formula (ISR was underestimated in previous versions).
           New version includes ISR in leading-log approximation up to
           third order.  Parameter ISR_sqrts renamed to ISR_scale.
 
 ##################################################################
 
 2002-02-19
 	RELEASE: version 1.20
 	New process-generating method 'test' (dummy matrix element)
 	Compatibility with autoconf 2.50 and current O'Mega version
 
 2002-02-05
 	Prevent integration channels from being dropped (optionally)
 	New internal mapping for structure functions improves performance
 	Old whizard.phx file deleted after recompiling (could cause trouble)
 
 2002-01-24
 	Support for user-defined cuts and matrix element reweighting
 	STDHEP output now written by write_events_format=20 (was 3)
 
 2002-01-16
 	Improved structure function handling; small changes in user interface:
           new parameter structured_beams in &process_input
           parameter fixed_energy in &beam_input removed
 	Support for multiple initial states
 	Eta-phi (cone) cut possible (hadron collider applications)
 	Fixed bug: Whizard library was not always recompiled when necessary
 	Fixed bug: Default cuts were insufficient in some cases
 	Fixed bug: Unusable phase space mappings generated in some cases
 
 2001-12-06
 	Reorganized document source
 
 2001-12-05
 	Preliminary CIRCE2 support (no functionality yet)
 
 2001-11-27
 	Intel compiler support (does not yet work because of compiler bugs)
 	New cut and analysis mode cos-theta* and related
 	Fixed circular jetset_interface dependency warning
 	Some broadcast routines removed (parallel support disabled anyway)
 	Minor shifts in cleanup targets (Makefiles)
         Modified library search, check for pdflib8*
 
 2001-08-06
 	Fixed bug: I/O unit number could be undefined when reading phase space
 	Fixed bug: Unitialized variable could cause segfault when
                    event generation was disabled
 	Fixed bug: Undefined subroutine in CIRCE replacement module
 	Enabled feature: TGCs in O'Mega (not yet CompHEP!) matrix elements
 		   (CompHEP model sm-GF #5, O'Mega model SM_ac)
 	Fixed portability issue: Makefile did rely on PWD environment variable
 	Fixed portability issue: PYTHIA library search ambiguity resolved
 
 2001-08-01
 	Default whizard.prc and whizard.in depend on activated modules
 	Fixed bug: TEX=latex was not properly enabled when making plots
 
 2001-07-20
 	Fixed output settings in PERL script calls
 	Cache enabled in various configure checks
 
 2001-07-13
 	Support for multiple processes in a single WHIZARD run.  The
           integrations are kept separate, but the generated events are mixed
 	The whizard.evx format has changed (incompatible), including now
 	  the color flow information for PYTHIA fragmentation
 	Output files are now process-specific, except for the event file
 	Phase space file whizard.phs (if present) is used only as input,
 	  program-generated phase space is now in whizard.phx
 
 2001-07-10
 	Bug fix: Undefined parameters in parameters_SM_ac.f90 removed
 
 2001-07-04
 	Bug fix: Compiler options for the case OMEGA is disabled
 	Small inconsistencies in whizard.out format fixed
 
 2001-07-01
 	Workaround for missing PDFLIB dummy routines in PYTHIA library
 
 ##################################################################
 
 2001-06-30
 	RELEASE: version 1.13
 	Default path /cern/pro/lib in configure script
 
 2001-06-20
 	New fragmentation option: Interface for PYTHIA with full color flow
           information, beam remnants etc.
 
 2001-06-18
 	Severe bug fixed in madgraph interface: 3-gluon coupling was missing
 	Enabled color flow information in madgraph
 
 2001-06-11
 	VAMP interface module rewritten
 	Revised output format: Multiple VAMP iterations count as one WHIZARD
           iteration in integration passes 1 and 3
 	Improved message and error handling
 	Bug fix in VAMP: handle exceptional cases in rebinning_weights
 
 2001-05-31
 	new parameters for grid adaptation: accuracy_goal and efficiency_goal
 
 ##################################################################
 
 2001-05-29
 	RELEASE: version 1.12
 	bug fixes (compilation problems): deleted/modified unused functions
 
 2001-05-16
 	diagram selection improved and documented
 
 2001-05-06
         allow for disabling packages during configuration
 
 2001-05-03
 	slight changes in whizard.out format; manual extended
 
 ##################################################################
 
 2001-04-20
 	RELEASE: version 1.11
 	fixed some configuration and compilation problems (PDFLIB etc.)
 
 2001-04-18
 	linked PDFLIB: support for quark/gluon structure functions
 
 2001-04-05
 	parameter interface written by PERL script
 	SM_ac model file: fixed error in continuation line
 
 2001-03-13
 	O'Mega, O'Caml 3.01: incompatible changes
 	O'Mega, src/trie.mli: add covariance annotation to T.t
 	  This breaks O'Caml 3.00, but is required for O'Caml 3.01.
 	O'Mega, many instances: replace `sig include Module.T end' by
 	  `Module.T', since the bug is fixed in O'Caml 3.01
 
 2001-02-28
 	O'Mega, src/model.mli:
             new field Model.vertices required for model functors, will
 	    retire Model.fuse2, Model.fuse3, Model.fusen soon.
 
 ##################################################################
 
 2001-03-27
 	RELEASE: version 1.10
 	reorganized the modules as libraries
 	linked PYTHIA: support for parton fragmentation
 
 2000-12-14
 	fixed some configuration problems (if noweb etc. are absent)
 
 ##################################################################
 
 2000-12-01
 	RELEASE of first public version: version 1.00beta