Index: web/trunk/documentation.ihtml =================================================================== --- web/trunk/documentation.ihtml (revision 1738) +++ web/trunk/documentation.ihtml (revision 1739) @@ -1,323 +1,323 @@ #include "applpre.ihtml" Instructions

Using the code

In APPLgrid, each cross section has it's own grid, stored in it's own grid file. For the convolution, you create a grid, specifying which file to use. For instance, a set of jet measurement with 5 different differential cross sections each corresponding to a different rapidity interval, will have 5 separate grids - one for each rapidity interval.

After installing the APPLgrid code itself, everything needed for reproducing a particular cross section is encapsulated in the grid itself - there is no need to download any additional code specific to that cross section.

As a result, unlike the fastNLO package, which requires both a grid file and a separate fortran routine for each cross section, since all information is encoded within the APPLgrid grids themselves it is simply enough to link against the APPLgrid code and call the convolute method for the appropriate grid, 
       // read the grid
       appl::grid grid_eta1("atlas-incljets06-eta1.root");
       
       // perform the convolution
       std::vector< double > xsec_eta1 = grid_eta1.vconvolute( evolvepdf_, alphasqcd_ );
The convolution will use whichever PDF and alphas routines are passed into it. If you have multiple PDFs set up, no additional code modification is required. For multiple grids, simply create new instances, specifying the appropriate grid file in the constructor. For example 
       /// load the grids
       appl::grid grid_eta1("atlas-incljets06-eta1.root");
       appl::grid grid_eta2("atlas-incljets06-eta2.root");
       
       /// perform the convolutions
       std::vector< double > xsec_eta1 = grid_eta1.vconvolute( evolvepdf_, alphasqcd_ );
       std::vector< double > xsec_eta2 = grid_eta2.vconvolute( evolvepdf_, alphasqcd_ );

These latest downloadable grids require no additional scaling and in addition, include the non-perturbative (or additional) bin-by-bin corrections discussed in the relevant papers.

By default, the convolution will return just the NLO cross section without application of the additional bin-by-bin. In order to obtain the complete cross section including the bin-by-bin corrections the class method, eg. for grid grid_eta1 then 

   grid_eta1.setApplyCorrections(true);
should be called before performing the convolution. All subsequent convolutions will also apply the corrections. To disable this for grid grid_eta1 call 
   grid_eta1.setApplyCorrections(false);
and subsequent convolutions will not apply the corrections.

fastNLO interface

There is also an interface for fastNLO grids, however, since these contain multiple different cross sections, the interface returns a vector of grids, that the user is free to call the convolution 
       /// read the fastnlo "scenario"
       fastnlo f( gridname );
       
       /// get the individual grids
       std::vector< appl::grid* > g = f.grids(); 
       
       /// vectopr for the different cross sections
       std::vector< std::vector < double > > xsec(g.size());
       for ( int i=0 ; i < g.size() ; i++ ) xsec[i] = g[i]-> vconvolute(  evolvepdf_, alphasqcd_ );
Besides the usual setting up of LHAPDF if it is being used etc, no additional coding is required. In addition to the methods which return the cross section values as simple vectors, routines also exist to return the cropss section directly as a root TH1D, with the appropriate binning 
       TH1D* hxsec_eta1 = grid_eta1.convolute( evolvepdf_, alphasqcd_ );
As with all root usage, the user should remember to delete the histogram when they have finished with it, should it be required.

Fortran interface

There is a fortran interface, however, since the functionality provided by the APPLgrid code is far more than can be expressed using simple fortran code. For instance, in fortran it is not possible to have multiple instances of complex data types. To get round this obvious limitation, specifying a grid by passing some integer identifer is the solution used in the APPLgrid fortran instance. In fastNLO, this limitation gives rise to the need for different functions for each cross section using fastNLO.

If the user must use fortran, we recommend making their basic data structures used in fortran available to code written in C++ and then writing the APPLgrid access code in C++ rather than use the fortran interface. We recommend this approach, since it is usually preferable for the user to write a wrapper for their own fortran code which will use only basic data types and so they will be free to develop this as they wish, and maintain access to the full, rich APPLgrid functionality, rather than have to request access to existing APPLgrid features that are not implemented in the fortran interface due to limitations or the fortran language.

Examples of how to this might be achieved are available in the full source tree. For addition advice, the user can of course contact us.


Getting Started - compiling the example

Remarks

There is the useful 
       applgrid-config
utility which provides locations of the installation directory, useful include and linking flags etc, eg 
       % applgrid-config --help
       applgrid-config: configuration tool for the APPLgrid
       fast cross section convolution code
       http://projects.hepforge.org/applgrid/
       
       Usage: applgrid-config [[--help|-h] | [--prefix] | [...]]
       Options:
       --help | -h    : this help
       
       --prefix       : installation prefix (cf. autoconf)
       --incdir       : path to the APPLgrid header directory
       --libdir       : path to the APPLgrid library directory
       --cxxflags     : compiler flags for the C preprocessor
       --ldflags      : compiler flags for the linker just for c code
       --ldfflags     : compiler flags for the linker including the fortan interface
       --share        : path to APPLgrid pdf conbination config files
 
       --version      : release version number
For general compilation and linkage with the users own code, the header and library paths can be specifed to the compiler and linker using the applgrid-config utility as follows 
       % applgrid-config --ldflags
       -L/usr/local/lib -lAPPLgrid -lfAPPLgrid
       
       % applgrid-config --cxxflags
       -I/usr/local/include


Renormalization and Factorization Scales

For grids cross sections up to NLO, all cross sections can be computed with and different scale factors for the renormalisation scales, ie muR, 2muR, 4muR etc. Any, arbitrary numerical scaling factor can be specified by the user, although changes to use a different scale, ie pT, rather than \hat{s} etc are not currently possible. For changes to the factorisation scale, again any arbitrary numerical factor can be specified by the user, although in this case, APPLgrid uses the hoppet package, so this needs to be installed before APPLgrid.


Interfacing your own PDF/alphas code

If you wish to interface your own PDF or alphas code, you simply need to define a function with the same specification at the evolvePDF and alphaQCD routines from the LHAPDF package. Remember that since the LHAPDF routines are in fortran, then your PDF and alphas functions should have extern "C" linkage.


If you have any further questions, please contact the authors at: applgrid @ projects.hepforge.org #include "applpost.ihtml" Index: web/trunk/date.txt =================================================================== --- web/trunk/date.txt (revision 1738) +++ web/trunk/date.txt (revision 1739) @@ -1 +1 @@ -Tue 23 Oct 2018 13:25:34 CEST +Sun 28 Oct 2018 16:45:44 CET Index: web/trunk/version.dat =================================================================== --- web/trunk/version.dat (revision 1738) +++ web/trunk/version.dat (revision 1739) @@ -1 +1 @@ -0.0.18 +0.0.19 Index: web/trunk/applbar.ihtml =================================================================== --- web/trunk/applbar.ihtml (revision 1738) +++ web/trunk/applbar.ihtml (revision 1739) @@ -1,57 +1,58 @@ #include "applcolours.ihtml" #define MENU_ITEM_WIDTH 16.6%
Home Downloads Documentation - + + Subversion Nightlies News Links
Index: web/trunk/applsidebar.ihtml =================================================================== --- web/trunk/applsidebar.ihtml (revision 1738) +++ web/trunk/applsidebar.ihtml (revision 1739) @@ -1,169 +1,169 @@ #include "applcolours.ihtml" #include "applversions.ihtml"
Convolution Code Download
-Current version +Current version applgrid-APPLVER
Basic example code - + here
The hoppet code version HOPPETVER for QCD evolution from Gavin Salam and Juan Rojo.

Calculation Code
MCFM: (use standard mcfm code)
- + mcfm-patch (mcfm applgrid patch MCFMVER)
- + mcfm-bridge (version MCFMBRIDGEVER - for mcfm-6.8)
NLOjet++:
- + nlojet++ 4.0.1 (applgrid version NLOVER)
- + nlojet++ lhapdf wrapper 1.0.0 (applgrid version NLHVER)
- + nlojet++ user module (applgrid version JMODVER)
Grid Download
Full details on the Downloads page:
#include "gridsbar.ihtml"
Quick Start Guide
how to run the APPLgrid code

Citation
Please cite the APPLgrid as
Eur Phys J C 66 (2010) 503

Index: web/trunk/downloads.ihtml =================================================================== --- web/trunk/downloads.ihtml (revision 1738) +++ web/trunk/downloads.ihtml (revision 1739) @@ -1,154 +1,154 @@ #include "applpre.ihtml" #include "applversions.ihtml"
Grid Downloads
Here you can download grids for APPLgrid version APPLVER for fast cross section evaluation. These grids are fully differential and should require no additional scaling. Each should include the non-perturbative (and any additional) bin-by-bin corrections or K-factors, the application of which is discussed in the relevant papers - see the Documentation page for more information.

Please note that these grids should be based on the grids that were used for the relevant papers, and were not necessarily created by the the applgrid authors.

In the future, it is hoped that grids will be distributed using the ploughshare project.

#include "grids.ihtml" 		Code Download
Various code for download is available:
  • You can download the latest version (APPLVER) of the standard APPLgrid convolution code - + here .
  • If you wish to use arbitrary factorisation scale variation, you will need to have hoppet installed first, which you can download from here .
  • There are some simple examples which you can download from - + here . These examples requires that you have LHAPDF installed which you can find here .
  • In addition, APPLgrid uses root files for storage, although not internally, so you should also install root which you can find here .

Calculation Code
If you wish to generate your own grids, we currently have NLOjet++ available for jet production at NLO and MCFM for most other processes.

  • For NLOjet++ we have our own custom version 4.0.1 which can be downloaded from - here . + here .
    This requires the nlojet pdf module that you can download from - here . + here .
    The user module can be downloaded from - here + here

  • For MCFM, you should download the standard version of MCFM (6.7 or later). To link with applgrid, before installing MCFM, you should download and install the - + mcfm-bridge code, which you install with the usual ./configure ; make ; make install etc.

    After running this you will need to patch the standard installation using the - patch file which you should untar in + patch file which you should untar in the MCFM base directory and then remove the file 
        src/User/gridwrap.f
    then just build using make. To link with applgrid, before running make, you should set the LDFLAGS enviroment variable to the output from 
        mcfm-bridge --ldflags
    NB: you should not use the standard install script that comes with MCFM.
Other interfaces are being developed and will be released when available.

Downloads Archive
The old downloads directory can be found here (Warning, not for the faint of heart)

#include "applpost.ihtml"