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ShowerHandler.h
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ShowerHandler.h
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// -*- C++ -*-
//
// ShowerHandler.h is a part of Herwig - A multi-purpose Monte Carlo event generator
// Copyright (C) 2002-2011 The Herwig Collaboration
//
// Herwig is licenced under version 2 of the GPL, see COPYING for details.
// Please respect the MCnet academic guidelines, see GUIDELINES for details.
//
#ifndef HERWIG_ShowerHandler_H
#define HERWIG_ShowerHandler_H
//
// This is the declaration of the ShowerHandler class.
//
#include "ThePEG/Handlers/EventHandler.h"
#include "ThePEG/Handlers/CascadeHandler.h"
#include "Herwig/Shower/UEBase.h"
#include "Herwig/Shower/Base/Evolver.fh"
#include "Herwig/Shower/Base/ShowerParticle.fh"
#include "Herwig/Shower/Base/ShowerTree.fh"
#include "Herwig/Shower/Base/HardTree.fh"
#include "Herwig/PDF/HwRemDecayer.fh"
#include "ThePEG/EventRecord/RemnantParticle.fh"
#include "ShowerHandler.fh"
#include "Herwig/MatrixElement/Matchbox/Matching/HardScaleProfile.h"
namespace Herwig {
/**
* Typedef for the ShowerTree for the decays
*/
typedef multimap<Energy,ShowerTreePtr,std::greater<Energy> > ShowerDecayMap;
using namespace ThePEG;
/** \ingroup Shower
*
* This class is the main driver of the shower: it is responsible for
* the proper handling of all other specific collaborating classes
* and for the storing of the produced particles in the event record.
*
* @see \ref ShowerHandlerInterfaces "The interfaces"
*
* @see ThePEG::CascadeHandler
* @see MPIHandler
* @see HwRemDecayer
*/
class ShowerHandler: public CascadeHandler {
public:
/** Typedef for a pair of ThePEG::RemnantParticle pointers. */
typedef pair<tRemPPtr, tRemPPtr> RemPair;
/**
* The default constructor.
*/
ShowerHandler();
/**
* Destructor
*/
virtual ~ShowerHandler();
public:
/**
* The main method which manages the multiple interactions and starts
* the shower by calling cascade(sub, lastXC).
*/
virtual void cascade();
/**
* Hook to allow vetoing of event after showering hard sub-process
* as in e.g. MLM merging.
*/
virtual bool showerHardProcessVeto() { return false; };
/**
* Return true, if this cascade handler will perform reshuffling from hard
* process masses.
*/
virtual bool isReshuffling() const { return true; }
public:
/**@name Methods related to PDF freezing */
//@{
/**
* Get the PDF freezing scale
*/
Energy pdfFreezingScale() const {return pdfFreezingScale_;}
//@}
public:
/** @name Functions used by the persistent I/O system. */
//@{
/**
* Function used to write out object persistently.
* @param os the persistent output stream written to.
*/
void persistentOutput(PersistentOStream & os) const;
/**
* Function used to read in object persistently.
* @param is the persistent input stream read from.
* @param version the version number of the object when written.
*/
void persistentInput(PersistentIStream & is, int version);
//@}
/**
* The standard Init function used to initialize the interfaces.
* Called exactly once for each class by the class description system
* before the main function starts or
* when this class is dynamically loaded.
*/
static void Init();
public:
/** @name Functions to access information. */
//@{
/**
* Return true if currently the primary subprocess is showered.
*/
bool firstInteraction() const {
return ( subProcess_ ==
eventHandler()->currentCollision()->primarySubProcess() );
}
/**
* Return the currently used SubProcess.
*/
tSubProPtr currentSubProcess() const {
assert(subProcess_);
return subProcess_;
}
/**
* Return true if multiple parton interactions are switched on
* and can be used for this beam setup.
*/
bool isMPIOn() const {
return MPIHandler_ && MPIHandler_->beamOK();
}
/**
* Return the remnant decayer.
*/
tHwRemDecPtr remnantDecayer() const { return remDec_; }
//@}
/**
* Access to the Evolver
*/
tEvolverPtr evolver() const {return evolver_;}
/**
* Generate hard emissions for CKKW etc
*/
virtual HardTreePtr generateCKKW(ShowerTreePtr tree) const;
/**
* Return true, if the shower handler can generate a truncated
* shower for POWHEG style events generated using Matchbox
*/
virtual bool canHandleMatchboxTrunc() const { return false; }
/**
* The factorization scale factor.
*/
double factorizationScaleFactor() const {
if ( scaleFactorOption_ == 0 || !subProcess_ )
return factorizationScaleFactor_;
if ( scaleFactorOption_ == 1 )
return firstInteraction() ? factorizationScaleFactor_ : 1.0;
if ( scaleFactorOption_ == 2 )
return !firstInteraction() ? factorizationScaleFactor_ : 1.0;
return 1.0;
}
/**
* The renormalization scale factor.
*/
double renormalizationScaleFactor() const {
if ( scaleFactorOption_ == 0 || !subProcess_ )
return renormalizationScaleFactor_;
if ( scaleFactorOption_ == 1 )
return firstInteraction() ? renormalizationScaleFactor_ : 1.0;
if ( scaleFactorOption_ == 2 )
return !firstInteraction() ? renormalizationScaleFactor_ : 1.0;
return 1.0;
}
/**
* The scale factor for the hard scale
*/
double hardScaleFactor() const {
if ( scaleFactorOption_ == 0 || !subProcess_ )
return hardScaleFactor_;
if ( scaleFactorOption_ == 1 )
return firstInteraction() ? hardScaleFactor_ : 1.0;
if ( scaleFactorOption_ == 2 )
return !firstInteraction() ? hardScaleFactor_ : 1.0;
return 1.0;
}
/**
* The option on when to apply the scale factors
*/
int scaleFactorOption() const { return scaleFactorOption_; }
/**
* Return true, if the phase space restrictions of the dipole shower should
* be applied.
*/
bool restrictPhasespace() const { return restrictPhasespace_; }
/**
* Return profile scales
*/
Ptr<HardScaleProfile>::tptr profileScales() const { return hardScaleProfile_; }
/**
* Return the relevant hard scale to be used in the profile scales
*/
virtual Energy hardScale() const;
/**
* Return true if maximum pt should be deduced from the factorization scale
*/
bool hardScaleIsMuF() const { return maxPtIsMuF_; }
protected:
/** @name Clone Methods. */
//@{
/**
* Make a simple clone of this object.
* @return a pointer to the new object.
*/
virtual IBPtr clone() const;
/** Make a clone of this object, possibly modifying the cloned object
* to make it sane.
* @return a pointer to the new object.
*/
virtual IBPtr fullclone() const;
//@}
protected:
/**
* Prepare to shower the given subprocess
*/
void prepareCascade(tSubProPtr sub);
/**
* The main method which manages the showering of a subprocess.
*/
virtual tPPair cascade(tSubProPtr sub, XCPtr xcomb);
/**
* Return the maximum number of attempts for showering
* a given subprocess.
*/
unsigned int maxtry() const { return maxtry_; }
/**
* At the end of the Showering, transform ShowerParticle objects
* into ThePEG particles and fill the event record with them.
* Notice that the parent/child relationships and the
* transformation from ShowerColourLine objects into ThePEG
* ColourLine ones must be properly handled.
*/
void fillEventRecord();
/**
* Find the parton extracted from the incoming particle after ISR
*/
PPtr findFirstParton(tPPtr seed) const;
/**
* Fix Remnant connections after ISR
*/
tPPair remakeRemnant(tPPair oldp);
/**
* Get the remnants from the ThePEG::PartonBinInstance es and
* do some checks.
*/
RemPair getRemnants(PBIPair incbins);
/**
* Make the remnant after the shower
*/
void makeRemnants();
/**
* Reset the PDF's after the hard collision has been showered
*/
void setMPIPDFs();
/**
* Boost all the particles in the collision so that the collision always occurs
* in the rest frame with the incoming particles along the z axis
*/
void boostCollision(bool boost);
/**
* Is a beam particle where hadronic structure is resolved
*/
bool isResolvedHadron(tPPtr);
protected:
/** @name Standard Interfaced functions. */
//@{
/**
* Initialize this object after the setup phase before saving an
* EventGenerator to disk.
* @throws InitException if object could not be initialized properly.
*/
virtual void doinit();
/**
* Initialize this object. Called in the run phase just before
* a run begins.
*/
virtual void doinitrun();
/**
* Called at the end of the run phase.
*/
virtual void dofinish();
//@}
private:
/**
* The assignment operator is private and must never be called.
* In fact, it should not even be implemented.
*/
ShowerHandler & operator=(const ShowerHandler &);
private:
/**
* Access function for the MPIHandler, it should only be called after
* checking with isMPIOn.
*/
tUEBasePtr getMPIHandler() const {
assert(MPIHandler_);
return MPIHandler_;
}
private:
/**
* a MPIHandler to administer the creation of several (semihard)
* partonic interactions.
*/
UEBasePtr MPIHandler_;
/**
* Pointer to the evolver
*/
EvolverPtr evolver_;
/**
* Pointer to the HwRemDecayer
*/
HwRemDecPtr remDec_;
/**
* The PDF for beam particle A. Overrides the particle's own PDF setting.
*/
PDFPtr PDFA_;
/**
* The PDF for beam particle B. Overrides the particle's own PDF setting.
*/
PDFPtr PDFB_;
/**
* The PDF for beam particle A for remnant splitting. Overrides the particle's own PDF setting.
*/
PDFPtr PDFARemnant_;
/**
* The PDF for beam particle B for remnant splitting. Overrides the particle's own PDF setting.
*/
PDFPtr PDFBRemnant_;
/**
* The PDF freezing scale
*/
Energy pdfFreezingScale_;
/**
* Maximum number of attempts for the
* main showering loop
*/
unsigned int maxtry_;
/**
* Maximum number of attempts for the regeneration of an additional
* scattering, before the number of scatters is reduced.
*/
unsigned int maxtryMPI_;
/**
* Maximum number of attempts for the regeneration of an additional
* hard scattering, before this event is vetoed.
*/
unsigned int maxtryDP_;
/**
* PDG codes of the particles which decay during showering
* this is fast storage for use during running
*/
set<long> particlesDecayInShower_;
/**
* PDG codes of the particles which decay during showering
* this is a vector that is interfaced so they can be changed
*/
vector<long> inputparticlesDecayInShower_;
/**
* Whether or not to include spa-cetime distances in the shower
*/
bool includeSpaceTime_;
/**
* The minimum virtuality for the space-time model
*/
Energy2 vMin_;
/**
* The ShowerTree for the hard process
*/
ShowerTreePtr hard_;
/**
* The incoming beam particles for the current collision
*/
tPPair incoming_;
/**
* The ShowerTree for the decays
*/
ShowerDecayMap decay_;
/**
* The ShowerTrees for which the initial shower
*/
vector<ShowerTreePtr> done_;
/**
* Const pointer to the current step
*/
tcStepPtr current_;
/**
* Const pointer to the currently handeled ThePEG::SubProcess
*/
tSubProPtr subProcess_;
/**
* pointer to "this", the current ShowerHandler.
*/
static ShowerHandler * currentHandler_;
/**
* Boost to get back to the lab
*/
LorentzRotation boost_;
/**
* The MPI PDF's to be used for secondary scatters.
*/
pair <PDFPtr, PDFPtr> mpipdfs_;
/**
* The MPI PDF's to be used for secondary scatters.
*/
pair <PDFPtr, PDFPtr> rempdfs_;
/**
* The MPI PDF's to be used for secondary scatters.
*/
pair <PDFPtr, PDFPtr> remmpipdfs_;
/**
* The factorization scale factor.
*/
double factorizationScaleFactor_;
/**
* The renormalization scale factor.
*/
double renormalizationScaleFactor_;
/**
* The scale factor for the hard scale
*/
double hardScaleFactor_;
/**
* The option on when to apply the scale factors
*/
int scaleFactorOption_;
/**
* True, if the phase space restrictions of the dipole shower should
* be applied.
*/
bool restrictPhasespace_;
/**
* True if maximum pt should be deduced from the factorization scale
*/
bool maxPtIsMuF_;
/**
* The profile scales
*/
Ptr<HardScaleProfile>::ptr hardScaleProfile_;
/**
* Whether or not to split into hard and decay trees
*/
bool splitHardProcess_;
public:
/**
* struct that is used to catch exceptions which are thrown
* due to energy conservation issues of additional scatters
*/
struct ExtraScatterVeto {};
/**
* struct that is used to catch exceptions which are thrown
* due to fact that the Shower has been invoked more than
* a defined threshold on a certain configuration
*/
struct ShowerTriesVeto {
/** variable to store the number of attempts */
const int tries;
/** constructor */
ShowerTriesVeto(int t) : tries(t) {}
};
/**
* pointer to "this", the current ShowerHandler.
*/
static const ShowerHandler * currentHandler() {
assert(currentHandler_);
return currentHandler_;
}
protected:
/**
* Set the current handler
*/
void setCurrentHandler() {
currentHandler_ = this;
}
};
}
#endif /* HERWIG_ShowerHandler_H */

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