genie::DFRKinematicsGenerator Class Reference

Generates kinematics for diffractive reactions. Is a concrete implementation of the EventRecordVisitorI interface. More...

#include <DFRKinematicsGenerator.h>

Inheritance diagram for genie::DFRKinematicsGenerator:

Collaboration diagram for genie::DFRKinematicsGenerator:

Public Member Functions
	DFRKinematicsGenerator ()
	DFRKinematicsGenerator (string config)
	~DFRKinematicsGenerator ()
void	ProcessEventRecord (GHepRecord *event_rec) const
void	Configure (const Registry &config)
void	Configure (string config)
Public Member Functions inherited from genie::EventRecordVisitorI
virtual	~EventRecordVisitorI ()
Public Member Functions inherited from genie::Algorithm
virtual	~Algorithm ()
virtual void	FindConfig (void)
virtual const Registry &	GetConfig (void) const
Registry *	GetOwnedConfig (void)
virtual const AlgId &	Id (void) const
	Get algorithm ID.
virtual AlgStatus_t	GetStatus (void) const
	Get algorithm status.
virtual bool	AllowReconfig (void) const
virtual AlgCmp_t	Compare (const Algorithm *alg) const
	Compare with input algorithm.
virtual void	SetId (const AlgId &id)
	Set algorithm ID.
virtual void	SetId (string name, string config)
const Algorithm *	SubAlg (const RgKey &registry_key) const
void	AdoptConfig (void)
void	AdoptSubstructure (void)
virtual void	Print (ostream &stream) const
	Print algorithm info.

Private Member Functions
void	LoadConfig (void)
double	ComputeMaxXSec (const Interaction *interaction) const

Private Attributes
double	fBeta

Additional Inherited Members
Static Public Member Functions inherited from genie::Algorithm
static string	BuildParamVectKey (const std::string &comm_name, unsigned int i)
static string	BuildParamVectSizeKey (const std::string &comm_name)
static string	BuildParamMatKey (const std::string &comm_name, unsigned int i, unsigned int j)
static string	BuildParamMatRowSizeKey (const std::string &comm_name)
static string	BuildParamMatColSizeKey (const std::string &comm_name)
Protected Member Functions inherited from genie::KineGeneratorWithCache
	KineGeneratorWithCache ()
	KineGeneratorWithCache (string name)
	KineGeneratorWithCache (string name, string config)
	~KineGeneratorWithCache ()
virtual double	ComputeMaxXSec (const Interaction *in, const int nkey) const
virtual double	MaxXSec (GHepRecord *evrec, const int nkey=0) const
virtual double	FindMaxXSec (const Interaction *in, const int nkey=0) const
virtual void	CacheMaxXSec (const Interaction *in, double xsec, const int nkey=0) const
virtual double	Energy (const Interaction *in) const
virtual CacheBranchFx *	AccessCacheBranch (const Interaction *in, const int nkey=0) const
virtual void	AssertXSecLimits (const Interaction *in, double xsec, double xsec_max) const
Protected Member Functions inherited from genie::EventRecordVisitorI
	EventRecordVisitorI ()
	EventRecordVisitorI (string name)
	EventRecordVisitorI (string name, string config)
Protected Member Functions inherited from genie::Algorithm
	Algorithm ()
	Algorithm (string name)
	Algorithm (string name, string config)
void	Initialize (void)
void	DeleteConfig (void)
void	DeleteSubstructure (void)
Registry *	ExtractLocalConfig (const Registry &in) const
Registry *	ExtractLowerConfig (const Registry &in, const string &alg_key) const
	Split an incoming configuration Registry into a block valid for the sub-algo identified by alg_key.
template<class T>
bool	GetParam (const RgKey &name, T &p, bool is_top_call=true) const
template<class T>
bool	GetParamDef (const RgKey &name, T &p, const T &def) const
template<class T>
int	GetParamVect (const std::string &comm_name, std::vector< T > &v, bool is_top_call=true) const
	Handle to load vectors of parameters.
int	GetParamVectKeys (const std::string &comm_name, std::vector< RgKey > &k, bool is_top_call=true) const
template<class T>
int	GetParamMat (const std::string &comm_name, TMatrixT< T > &mat, bool is_top_call=true) const
	Handle to load matrix of parameters.
template<class T>
int	GetParamMatSym (const std::string &comm_name, TMatrixTSym< T > &mat, bool is_top_call=true) const
int	GetParamMatKeys (const std::string &comm_name, std::vector< RgKey > &k, bool is_top_call=true) const
int	AddTopRegistry (Registry *rp, bool owns=true)
	add registry with top priority, also update ownership
int	AddLowRegistry (Registry *rp, bool owns=true)
	add registry with lowest priority, also update ownership
int	MergeTopRegistry (const Registry &r)
int	AddTopRegisties (const vector< Registry * > &rs, bool owns=false)
	Add registries with top priority, also udated Ownerships.
Protected Attributes inherited from genie::KineGeneratorWithCache
const XSecAlgorithmI *	fXSecModel
double	fSafetyFactor
	ComputeMaxXSec -> ComputeMaxXSec * fSafetyFactor.
std::vector< double >	vSafetyFactors
	MaxXSec -> MaxXSec * fSafetyFactors[nkey].
int	fNumOfSafetyFactors
	Number of given safety factors.
std::vector< string >	vInterpolatorTypes
	Type of interpolator for each key in a branch.
int	fNumOfInterpolatorTypes
	Number of given interpolators types.
double	fMaxXSecDiffTolerance
	max{100*(xsec-maxxsec)/.5*(xsec+maxxsec)} if xsec>maxxsec
double	fEMin
	min E for which maxxsec is cached - forcing explicit calc.
bool	fGenerateUniformly
	uniform over allowed phase space + event weight?
Protected Attributes inherited from genie::Algorithm
bool	fAllowReconfig
bool	fOwnsSubstruc
	true if it owns its substructure (sub-algs,...)
AlgId	fID
	algorithm name and configuration set
vector< Registry * >	fConfVect
vector< bool >	fOwnerships
	ownership for every registry in fConfVect
AlgStatus_t	fStatus
	algorithm execution status
AlgMap *	fOwnedSubAlgMp
	local pool for owned sub-algs (taken out of the factory pool)

Detailed Description

Generates kinematics for diffractive reactions. Is a concrete implementation of the EventRecordVisitorI interface.

Author

Costas Andreopoulos <c.andreopoulos \at cern.ch> University of Liverpool

Created:\n Feb 15, 2009

License:\n Copyright (c) 2003-2025, The GENIE Collaboration

For the full text of the license visit http://copyright.genie-mc.org

Definition at line 27 of file DFRKinematicsGenerator.h.

Constructor & Destructor Documentation

DFRKinematicsGenerator() [1/2]

DFRKinematicsGenerator::DFRKinematicsGenerator

(

)

Definition at line 39 of file DFRKinematicsGenerator.cxx.

                                               :
KineGeneratorWithCache("genie::DFRKinematicsGenerator")
{
 
}

References genie::KineGeneratorWithCache::KineGeneratorWithCache().

DFRKinematicsGenerator() [2/2]

DFRKinematicsGenerator::DFRKinematicsGenerator

(

string

config

)

Definition at line 45 of file DFRKinematicsGenerator.cxx.

                                                            :
KineGeneratorWithCache("genie::DFRKinematicsGenerator", config)
{
 
}

References genie::KineGeneratorWithCache::KineGeneratorWithCache().

~DFRKinematicsGenerator()

DFRKinematicsGenerator::~DFRKinematicsGenerator

(

)

Definition at line 51 of file DFRKinematicsGenerator.cxx.

{
 
}

Member Function Documentation

ComputeMaxXSec()

double DFRKinematicsGenerator::ComputeMaxXSec ( const Interaction * interaction ) const

privatevirtual

Implements genie::KineGeneratorWithCache.

Definition at line 250 of file DFRKinematicsGenerator.cxx.

{
// Computes the maximum differential cross section in the requested phase
// space. This method overloads KineGeneratorWithCache::ComputeMaxXSec
// method and the value is cached at a circular cache branch for retrieval
// during subsequent event generation.
// The computed max differential cross section does not need to be the exact
// maximum. The number used in the rejection method will be scaled up by a
// safety factor. But this needs to be fast - do not use a very fine grid.
 
#ifdef __GENIE_LOW_LEVEL_MESG_ENABLED__
  LOG("DFRKinematics", pDEBUG)
      << "Computing max xsec in allowed phase space";
#endif
  double max_xsec = 0.0;
 
  const KPhaseSpace & kps = interaction->PhaseSpace();
  Range1D_t xl  = kps.XLim();
  Range1D_t yl  = kps.YLim();
  Range1D_t Wl  = kps.WLim();
 
  int    Ny      = 20;
  int    Nx      = 20;
  int    Nt      = 10;
  double xmin    = xl.min;
  double xmax    = xl.max;
  double ymin    = yl.min;
  double ymax    = yl.max;
  double dx      = (xmax-xmin)/(Nx-1);
  double dy      = (ymax-ymin)/(Ny-1);
 
 
#ifdef __GENIE_LOW_LEVEL_MESG_ENABLED__
  LOG("DFRKinematics", pDEBUG)
    << "Searching max. in x [" << xmin << ", " << xmax
    << "], y [" << ymin << ", " << ymax << "], z [" << zmin << ", " << zmax << "]";
#endif
  double xseclast_y = -1;
  bool increasing_y;
 
  for(int i=0; i<Ny; i++) {
     double gy = ymin + i*dy;
     interaction->KinePtr()->Sety(gy);
 
#ifdef __GENIE_LOW_LEVEL_MESG_ENABLED__
     LOG("DFRKinematics", pDEBUG) << "y = " << gy;
#endif
     for(int j=0; j<Nx; j++) {
        double gx = xmin + j*dx;
        interaction->KinePtr()->Setx(gx);
        kinematics::UpdateWQ2FromXY(interaction);
        Range1D_t Q2l = kps.Q2Lim_W();
 
        // the t range depends on x and y,
        // and you get NaNs if you try to calculate t
        // for an unphysical (x,y) combination
        bool in_phys = math::IsWithinLimits(interaction->KinePtr()->W(), Wl);
        in_phys = in_phys && math::IsWithinLimits(interaction->KinePtr()->Q2(), Q2l);
        if (!in_phys)
          continue;
 
        // t range depends on x and y
        Range1D_t tl = kps.TLim();
        double tmin    = tl.min;
        double tmax    = tl.max;
        double dt      = (tmax-tmin)/(Nt-1);
        for(int k=0; k<Nt; k++) {
          double gt = tmin + k*dt;
          interaction->KinePtr()->Sett(gt);
 
          double xsec = fXSecModel->XSec(interaction, kPSxytfE);
#ifdef __GENIE_LOW_LEVEL_MESG_ENABLED__
          LOG("DFRKinematics", pINFO)
            << "xsec(y=" << gy << ", x=" << gx << ", t=" << gt << ") = " << xsec;
#endif
          // update maximum xsec
          max_xsec = TMath::Max(xsec, max_xsec);
        } // t
      } // x
    increasing_y = max_xsec-xseclast_y>=0;
    xseclast_y   = max_xsec;
    if(!increasing_y) {
#ifdef __GENIE_LOW_LEVEL_MESG_ENABLED__
      LOG("DFRKinematics", pDEBUG)
        << "d2xsec/dxdy stopped increasing. Exiting y loop";
#endif
      break;
    }
  }// y
 
  // Apply safety factor, since value retrieved from the cache might
  // correspond to a slightly different energy
  max_xsec *= 3;
 
#ifdef __GENIE_LOW_LEVEL_MESG_ENABLED__
  SLOG("DFRKinematics", pDEBUG) << interaction->AsString();
  SLOG("DFRKinematics", pDEBUG) << "Max xsec in phase space = " << max_xsec;
  SLOG("DFRKinematics", pDEBUG) << "Computed using alg = " << *fXSecModel;
#endif
 
  return max_xsec;
}

References genie::Interaction::AsString(), genie::KineGeneratorWithCache::fXSecModel, genie::utils::math::IsWithinLimits(), genie::Interaction::KinePtr(), genie::kPSxytfE, LOG, genie::Range1D_t::max, genie::Range1D_t::min, pDEBUG, genie::Interaction::PhaseSpace(), pINFO, genie::Kinematics::Q2(), genie::KPhaseSpace::Q2Lim_W(), genie::Kinematics::Sett(), genie::Kinematics::Setx(), genie::Kinematics::Sety(), SLOG, genie::KPhaseSpace::TLim(), genie::utils::kinematics::UpdateWQ2FromXY(), genie::Kinematics::W(), genie::KPhaseSpace::WLim(), genie::KPhaseSpace::XLim(), and genie::KPhaseSpace::YLim().

Configure() [1/2]

void DFRKinematicsGenerator::Configure ( const Registry & config )

virtual

Configure the algorithm with an external registry The registry is merged with the top level registry if it is owned, Otherwise a copy of it is added with the highest priority

Reimplemented from genie::Algorithm.

Definition at line 213 of file DFRKinematicsGenerator.cxx.

{
  Algorithm::Configure(config);
  this->LoadConfig();
}

References genie::Algorithm::Configure(), and LoadConfig().

Configure() [2/2]

void DFRKinematicsGenerator::Configure ( string config )

virtual

Configure the algorithm from the AlgoConfigPool based on param_set string given in input An algorithm contains a vector of registries coming from different xml configuration files, which are loaded according a very precise prioriy This methods will load a number registries in order of priority: 1) "Tunable" parameter set from CommonParametes. This is loaded with the highest prioriry and it is designed to be used for tuning procedure Usage not expected from the user. 2) For every string defined in "CommonParame" the corresponding parameter set will be loaded from CommonParameter.xml 3) parameter set specified by the config string and defined in the xml file of the algorithm 4) if config is not "Default" also the Default parameter set from the same xml file will be loaded Effectively this avoids the repetion of a parameter when it is not changed in the requested configuration

Reimplemented from genie::Algorithm.

Definition at line 219 of file DFRKinematicsGenerator.cxx.

{
  Algorithm::Configure(config);
  this->LoadConfig();
}

References genie::Algorithm::Configure(), and LoadConfig().

LoadConfig()

void DFRKinematicsGenerator::LoadConfig ( void )

private

Definition at line 225 of file DFRKinematicsGenerator.cxx.

{
// Reads its configuration data from its configuration Registry and loads them
// in private data members to avoid looking up at the Registry all the time.
 
  //-- Safety factor for the maximum differential cross section
  GetParamDef( "MaxXSec-SafetyFactor", fSafetyFactor, 1.25 ) ;
 
  //-- Minimum energy for which max xsec would be cached, forcing explicit
  //   calculation for lower eneries
  GetParamDef( "Cache-MinEnergy", fEMin, 0.8 ) ;
 
  //-- Maximum allowed fractional cross section deviation from maxim cross
  //   section used in rejection method
  GetParamDef( "MaxXSec-DiffTolerance", fMaxXSecDiffTolerance, 999999. ) ;
  assert(fMaxXSecDiffTolerance>=0);
 
  //-- Generate kinematics uniformly over allowed phase space and compute
  //   an event weight?
  GetParamDef( "UniformOverPhaseSpace", fGenerateUniformly, false ) ;
 
  GetParam( "DFR-Beta", fBeta ) ;
 
}

References fBeta, genie::KineGeneratorWithCache::fEMin, genie::KineGeneratorWithCache::fGenerateUniformly, genie::KineGeneratorWithCache::fMaxXSecDiffTolerance, genie::KineGeneratorWithCache::fSafetyFactor, genie::Algorithm::GetParam(), and genie::Algorithm::GetParamDef().

Referenced by Configure(), and Configure().

ProcessEventRecord()

void DFRKinematicsGenerator::ProcessEventRecord ( GHepRecord * event_rec ) const

virtual

Implements genie::EventRecordVisitorI.

Definition at line 56 of file DFRKinematicsGenerator.cxx.

{
  if(fGenerateUniformly) {
    LOG("DFRKinematics", pNOTICE)
          << "Generating kinematics uniformly over the allowed phase space";
  }
 
  //-- Get the random number generators
  RandomGen * rnd = RandomGen::Instance();
 
  //-- Access cross section algorithm for running thread
  RunningThreadInfo * rtinfo = RunningThreadInfo::Instance();
  const EventGeneratorI * evg = rtinfo->RunningThread();
  fXSecModel = evg->CrossSectionAlg();
 
  //-- Get the interaction
  Interaction * interaction = evrec->Summary();
  interaction->SetBit(kISkipProcessChk);
 
  //-- Get neutrino energy and hit 'nucleon mass'
  const InitialState & init_state = interaction->InitState();
  double Ev  = init_state.ProbeE(kRfHitNucRest);
  double M   = init_state.Tgt().HitNucP4().M(); // can be off m-shell
 
  //-- Get the physical W range
  const KPhaseSpace & kps = interaction->PhaseSpace();
 
  Range1D_t xl = kps.Limits(kKVx);
  Range1D_t yl = kps.Limits(kKVy);
 
  // Note that the t limits used here are NOT the same as what you get from KPhaseSpace::TLim().
  // We use a larger range here because the limits from KPhaseSpace::TLim() depend on x and y,
  // and using the rejection method in a region that's changing depending on some of the
  // values guarantees that some regions will be oversampled.  We want to avoid that.
  Range1D_t tl;
  tl.min = 0;
  tl.max = KPhaseSpace::GetTMaxDFR();
 
  LOG("DFRKinematics", pNOTICE) << "x: [" << xl.min << ", " << xl.max << "]";
  LOG("DFRKinematics", pNOTICE) << "y: [" << yl.min << ", " << yl.max << "]";
  LOG("DFRKinematics", pNOTICE) << "t: [" << tl.min << ", " << tl.max << "]";
 
/*
  Range1D_t W  = kps.Limits(kKVW);
  if(W.max <=0 || W.min>=W.max) {
     LOG("DFRKinematics", pWARN) << "No available phase space";
     evrec->EventFlags()->SetBitNumber(kKineGenErr, true);
     genie::exceptions::EVGThreadException exception;
     exception.SetReason("No available phase space");
     exception.SwitchOnFastForward();
     throw exception;
  }
*/
 
  assert(xl.min>0 && yl.min>0);
 
  //-- For the subsequent kinematic selection with the rejection method:
  //   Calculate the max differential cross section or retrieve it from the
  //   cache. Throw an exception and quit the evg thread if a non-positive
  //   value is found.
  //   If the kinematics are generated uniformly over the allowed phase
  //   space the max xsec is irrelevant
  double xsec_max = (fGenerateUniformly) ? -1 : this->MaxXSec(evrec);
 
  //-- Try to select a valid (x,y,t) triplet using the rejection method
 
  double dx = xl.max - xl.min;
  double dy = yl.max - yl.min;
  double dt = tl.max - tl.min;
  double gx=-1, gy=-1, gt=-1, gW=-1, gQ2=-1, xsec=-1;
 
  unsigned int iter = 0;
  bool accept = false;
  while(true) {
     iter++;
     if(iter > kRjMaxIterations) {
       LOG("DFRKinematics", pWARN)
         << " Couldn't select kinematics after " << iter << " iterations";
       evrec->EventFlags()->SetBitNumber(kKineGenErr, true);
       genie::exceptions::EVGThreadException exception;
       exception.SetReason("Couldn't select kinematics");
       exception.SwitchOnFastForward();
       throw exception;
     }
 
     //-- random x,y,t
     gx = xl.min + dx * rnd->RndKine().Rndm();
     gy = yl.min + dy * rnd->RndKine().Rndm();
     gt = tl.min + dt * rnd->RndKine().Rndm();
 
     interaction->KinePtr()->Setx(gx);
     interaction->KinePtr()->Sety(gy);
     interaction->KinePtr()->Sett(gt);
 
     LOG("DFRKinematics", pDEBUG)
       << "Trying: x = " << gx << ", y = " << gy << ", t = " << gt;
 
     //-- compute the cross section for current kinematics
     xsec = fXSecModel->XSec(interaction, kPSxytfE);
 
     //-- decide whether to accept the current kinematics
     if(!fGenerateUniformly) {
        this->AssertXSecLimits(interaction, xsec, xsec_max);
        double n = xsec_max * rnd->RndKine().Rndm();
        double J = 1;
 
#ifdef __GENIE_LOW_LEVEL_MESG_ENABLED__
        LOG("DFRKinematics", pDEBUG)
              << "xsec= " << xsec << ", J= " << J << ", Rnd= " << n;
#endif
        accept = (n < J*xsec);
     }
     else {
       accept = (xsec>0);
     }
 
     //-- If the generated kinematics are accepted, finish-up module's job
     if(accept) {
         // reset trust bits
         interaction->ResetBit(kISkipProcessChk);
         interaction->ResetBit(kISkipKinematicChk);
 
         // for uniform kinematics, compute an event weight as
         // wght = (phase space volume)*(differential xsec)/(event total xsec)
         if(fGenerateUniformly) {
            double vol     = kinematics::PhaseSpaceVolume(interaction,kPSxytfE);
            double totxsec = evrec->XSec();
            double wght    = (vol/totxsec)*xsec;
            LOG("DFRKinematics", pNOTICE)  << "Kinematics wght = "<< wght;
 
            // apply computed weight to the current event weight
            wght *= evrec->Weight();
            LOG("DFRKinematics", pNOTICE) << "Current event wght = " << wght;
            evrec->SetWeight(wght);
         }
 
         // compute W,Q2 for selected x,y
         kinematics::XYtoWQ2(Ev,M,gW,gQ2,gx,gy);
 
         LOG("DFRKinematics", pNOTICE)
                << "Selected x,y => W = " << gW << ", Q2 = " << gQ2;
 
         // set the cross section for the selected kinematics
         evrec->SetDiffXSec(xsec, kPSxytfE);
 
         // lock selected kinematics & clear running values
         interaction->KinePtr()->SetW (gW,  true);
         interaction->KinePtr()->SetQ2(gQ2, true);
         interaction->KinePtr()->Setx (gx,  true);
         interaction->KinePtr()->Sety (gy,  true);
         interaction->KinePtr()->Sett (gt,  true);
         interaction->KinePtr()->ClearRunningValues();
         return;
     }
  } // iterations
}

References genie::KineGeneratorWithCache::AssertXSecLimits(), genie::Kinematics::ClearRunningValues(), genie::EventGeneratorI::CrossSectionAlg(), genie::GHepRecord::EventFlags(), genie::KineGeneratorWithCache::fGenerateUniformly, genie::KineGeneratorWithCache::fXSecModel, genie::KPhaseSpace::GetTMaxDFR(), gQ2, genie::Target::HitNucP4(), genie::Interaction::InitState(), genie::RandomGen::Instance(), genie::RunningThreadInfo::Instance(), genie::Interaction::KinePtr(), genie::kISkipKinematicChk, genie::kISkipProcessChk, genie::kKineGenErr, genie::kKVx, genie::kKVy, genie::kPSxytfE, genie::kRfHitNucRest, genie::controls::kRjMaxIterations, genie::KPhaseSpace::Limits(), LOG, genie::Range1D_t::max, genie::KineGeneratorWithCache::MaxXSec(), genie::Range1D_t::min, pDEBUG, genie::Interaction::PhaseSpace(), genie::utils::kinematics::PhaseSpaceVolume(), pNOTICE, genie::InitialState::ProbeE(), pWARN, genie::RandomGen::RndKine(), genie::RunningThreadInfo::RunningThread(), genie::GHepRecord::SetDiffXSec(), genie::Kinematics::SetQ2(), genie::exceptions::EVGThreadException::SetReason(), genie::Kinematics::Sett(), genie::Kinematics::SetW(), genie::GHepRecord::SetWeight(), genie::Kinematics::Setx(), genie::Kinematics::Sety(), genie::GHepRecord::Summary(), genie::exceptions::EVGThreadException::SwitchOnFastForward(), genie::InitialState::Tgt(), genie::GHepRecord::Weight(), genie::GHepRecord::XSec(), and genie::utils::kinematics::XYtoWQ2().

Member Data Documentation

fBeta

double genie::DFRKinematicsGenerator::fBeta

private

Definition at line 46 of file DFRKinematicsGenerator.h.

Referenced by LoadConfig().

---

The documentation for this class was generated from the following files:

• DFRKinematicsGenerator.h
• DFRKinematicsGenerator.cxx