GEVGDriver.cxx

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//____________________________________________________________________________
/*
 Copyright (c) 2003-2019, The GENIE Collaboration
 For the full text of the license visit http://copyright.genie-mc.org
 or see $GENIE/LICENSE

 Author: Costas Andreopoulos <costas.andreopoulos \at stfc.ac.uk>
         University of Liverpool & STFC Rutherford Appleton Lab
*/
//____________________________________________________________________________

#include <cassert>
#include <cstdlib>
#include <sstream>

#include <TSystem.h>
#include <TMath.h>

#include "Framework/Algorithm/AlgFactory.h"
#include "Framework/EventGen/XSecAlgorithmI.h"
#include "Framework/Conventions/Controls.h"
#include "Framework/Conventions/Units.h"
#include "Framework/EventGen/GEVGDriver.h"
#include "Framework/EventGen/EventRecord.h"
#include "Framework/EventGen/EventGeneratorList.h"
#include "Framework/EventGen/EventGeneratorI.h"
#include "Framework/EventGen/ToyInteractionSelector.h"
#include "Framework/EventGen/PhysInteractionSelector.h"
#include "Framework/EventGen/EventGeneratorListAssembler.h"
#include "Framework/EventGen/InteractionList.h"
#include "Framework/EventGen/InteractionListGeneratorI.h"
#include "Framework/EventGen/InteractionGeneratorMap.h"
#include "Framework/EventGen//RunningThreadInfo.h"
#include "Framework/GHEP/GHepFlags.h"
#include "Framework/Interaction/Interaction.h"
#include "Framework/Messenger/Messenger.h"
#include "Framework/Numerical/Spline.h"
#include "Framework/ParticleData/PDGCodes.h"
#include "Framework/ParticleData/PDGUtils.h"
#include "Framework/ParticleData/PDGLibrary.h"
#include "Framework/Utils/XSecSplineList.h"
#include "Framework/Utils/PrintUtils.h"

using std::ostringstream;

using namespace genie;
using namespace genie::controls;

//____________________________________________________________________________
namespace genie {
 ostream & operator<< (ostream& stream, const GEVGDriver & driver)
 {
   driver.Print(stream);
   return stream;
 }
}
//___________________________________________________________________________
GEVGDriver::GEVGDriver()
{
  this->Init();
}
//___________________________________________________________________________
GEVGDriver::~GEVGDriver()
{
  this->CleanUp();
}
//___________________________________________________________________________
void GEVGDriver::Init(void)
{
  // initial state for which this driver is configured
  fInitState = 0;

  // current event record (ownership is transfered at GenerateEvent())
  fCurrentRecord = 0;

  // list of Event Generator objects loaded into the driver
  fEvGenList = 0;

  // interaction selector
  fIntSelector = 0;

  // flag instructing the driver whether, for each interaction, to compute
  // cross section by running their corresponding XSecAlgorithm or by
  // evaluating their corresponding xsec spline
  fUseSplines = false;

  // set of event generators to be loaded by this driver
  fEventGenList = "Default";

  // 'depth' counter when entering a recursive mode to re-generate a failed/
  // unphysical event - the driver is not allowed to go into arbitrarily large
  // depths
  fNRecLevel = 0;

  // an "interaction" -> "generator" associative contained built for all
  // simulated interactions (from the loaded Event Generators and for the
  // input initial state)
  fIntGenMap = 0;

  // A spline describing the sum of all interaction cross sections given an
  // initial state (the init state with which this driver was configured).
  // Create it using the CreateXSecSumSpline() method
  // The sum of all interaction cross sections is used, for example, by
  // GMCJDriver for selecting an initial state.
  fXSecSumSpl = 0;

  // Default driver behaviour is to filter out unphysical events
  // If needed, set the fUnphysEventMask bitfield to get pre-selected types of
  // unphysical events (just set to 1 the bit you want ignored from the check).
  // Be warned that the event record for unphysical events might be incomplete
  // depending on the processing step that event generation was stopped.
  fUnphysEventMask = new TBits(GHepFlags::NFlags());
  //fUnphysEventMask->ResetAllBits(true);
  for(unsigned int i = 0; i < GHepFlags::NFlags(); i++) {
   fUnphysEventMask->SetBitNumber(i, true);
  }
  LOG("GEVGDriver", pNOTICE)
    << "Initializing unphysical event mask (bits: " << GHepFlags::NFlags()-1
    << " -> 0) : " << *fUnphysEventMask;
}
//___________________________________________________________________________
void GEVGDriver::CleanUp(void)
{
  if (fUnphysEventMask)  delete fUnphysEventMask;
  if (fInitState)        delete fInitState;
  if (fEvGenList)        delete fEvGenList;
  if (fIntSelector)      delete fIntSelector;
  if (fIntGenMap)        delete fIntGenMap;
  if (fXSecSumSpl)       delete fXSecSumSpl;
}
//___________________________________________________________________________
void GEVGDriver::Reset(void)
{
  this->CleanUp();
  this->Init();
}
//___________________________________________________________________________
void GEVGDriver::Configure(int nu_pdgc, int Z, int A)
{
  Target target(Z, A);
  InitialState init_state(target, nu_pdgc);

  this->Configure(init_state);
}
//___________________________________________________________________________
void GEVGDriver::Configure(const InitialState & is)
{
  InitialState init_state(is.TgtPdg(), is.ProbePdg()); // filter any other init state info

  ostringstream mesg;
  mesg << "Configuring event generation driver for initial state: `"
       << init_state.AsString()
       << "' using event generator list: `"
       << fEventGenList << "'.";

  LOG("GEVGDriver", pNOTICE)
        << utils::print::PrintFramedMesg(mesg.str(), 0, '*');

  this -> BuildInitialState            (init_state);
  this -> BuildGeneratorList           ();
  this -> BuildInteractionGeneratorMap ();
  this -> BuildInteractionSelector     ();

  LOG("GEVGDriver", pINFO) << "Done configuring. \n";
}
//___________________________________________________________________________
void GEVGDriver::BuildInitialState(const InitialState & init_state)
{
  LOG("GEVGDriver", pINFO) << "Setting the initial state";

  if(fInitState) delete fInitState;
  fInitState = new InitialState(init_state);

  this->AssertIsValidInitState();
}
//___________________________________________________________________________
void GEVGDriver::BuildGeneratorList(void)
{
//! Load event generators.
//! The list of event generators is named by fEventGenList.

  LOG("GEVGDriver", pINFO)
    << "Building the event generator list (specified list name: "
    << fEventGenList << ")";

  EventGeneratorListAssembler evglist_assembler(fEventGenList.c_str());
  fEvGenList = evglist_assembler.AssembleGeneratorList();
}
//___________________________________________________________________________
void GEVGDriver::BuildInteractionGeneratorMap(void)
{
//! Map each possible interaction, for the given initial state, to one
//! of the generators loaded up

  LOG("GEVGDriver", pINFO)
         << "Building the interaction -> generator associations...";

  fIntGenMap = new InteractionGeneratorMap;
  fIntGenMap->UseGeneratorList(fEvGenList);
  fIntGenMap->BuildMap(*fInitState);

  string mesgh = "Interaction -> Generator assignments for Initial State: ";

  LOG("GEVGDriver", pDEBUG)
    << utils::print::PrintFramedMesg(mesgh + fInitState->AsString(), 0, '-')
    << *fIntGenMap;
}
//___________________________________________________________________________
void GEVGDriver::BuildInteractionSelector(void)
{
  LOG("GEVGDriver", pINFO) << "Building the interaction selector...";

  AlgFactory * algf = AlgFactory::Instance();

  if(fIntSelector) delete fIntSelector;
  fIntSelector = dynamic_cast<InteractionSelectorI *> (
        algf->AdoptAlgorithm("genie::PhysInteractionSelector","Default"));
}
//___________________________________________________________________________
void GEVGDriver::SetUnphysEventMask(const TBits & mask)
{
  *fUnphysEventMask = mask;

  LOG("GEVGDriver", pNOTICE)
    << "Setting unphysical event mask (bits: " << GHepFlags::NFlags() - 1
    << " -> 0) : " << *fUnphysEventMask;
}
//___________________________________________________________________________
EventRecord * GEVGDriver::GenerateEvent(const TLorentzVector & nu4p)
{
  //-- Build initial state information from inputs
  LOG("GEVGDriver", pINFO) << "Creating the initial state";
  InitialState init_state(*fInitState);
  init_state.SetProbeP4(nu4p);

  //-- Select the interaction to be generated (amongst the entries of the
  //   InteractionList assembled by the EventGenerators) and bootstrap the
  //   event record
  LOG("GEVGDriver", pINFO)
     << "Selecting an Interaction & Bootstraping the EventRecord";
  fCurrentRecord = fIntSelector->SelectInteraction(fIntGenMap, nu4p);

  if(!fCurrentRecord) {
     LOG("GEVGDriver", pWARN)
         << "No interaction could be selected for: "
         << init_state.AsString() << " at E = " << nu4p.E() << " GeV";
     return 0;
  }

  //-- Get a ptr to the interaction summary
  LOG("GEVGDriver", pDEBUG) << "Getting the selected interaction";
  Interaction * interaction = fCurrentRecord->Summary();

  //-- Find the appropriate concrete EventGeneratorI implementation
  //   for generating this event.
  //
  //   The right EventGeneratorI will be selecting by iterating over the
  //   entries of the EventGeneratorList and compare the interaction
  //   against the ValidityContext declared by each EventGeneratorI
  //
  //   (note: use of the 'Chain of Responsibility' Design Pattern)

  LOG("GEVGDriver", pINFO) << "Finding an appropriate EventGenerator";

  const EventGeneratorI * evgen = fIntGenMap->FindGenerator(interaction);
  assert(evgen);

  RunningThreadInfo * rtinfo = RunningThreadInfo::Instance();
  rtinfo->UpdateRunningThread(evgen);

  //-- Generate the selected event
  //
  //   The selected EventGeneratorI subclass will start processing the
  //   event record (by sequentially asking each entry in its list of
  //   EventRecordVisitorI subclasses to visit and process the record).
  //   Most of the actual event generation takes place in this step.
  //
  //   (note: use of the 'Visitor' Design Pattern)

  string mesg = "Requesting from event generation thread: " +
         evgen->Id().Key() + " to generate the selected interaction";

  LOG("GEVGDriver", pNOTICE)
         << utils::print::PrintFramedMesg(mesg,1,'=');

  fCurrentRecord->SetUnphysEventMask(*fUnphysEventMask);
  evgen->ProcessEventRecord(fCurrentRecord);

  //-- Check the generated event flags. The default behaviour is
  //   to reject an unphysical event and enter in recursive mode
  //   and try to regenerate it. If an unphysical event mask has
  //   been set, error conditions may be ignored so that the
  //   requested classes of unphysical events can be passed-through.

  bool unphys = fCurrentRecord->IsUnphysical();
  if(!unphys) {
     LOG("GEVGDriver", pINFO) << "Returning the current event!";
     fNRecLevel = 0;
     return fCurrentRecord; // The client 'adopts' the event record
  } else {
     LOG("GEVGDriver", pWARN) << "An unphysical event was generated...";
     // Check whether the user wants to ignore the err
     bool accept = fCurrentRecord->Accept();
     if(accept) {
       LOG("GEVGDriver", pWARN)
          << "The generated unphysical event is accepted by the user";
       fNRecLevel = 0;
       return fCurrentRecord; // The client 'adopts' the event record

     } else {
       LOG("GEVGDriver", pWARN)
          << "The generated unphysical event is rejected";
       delete fCurrentRecord;
       fCurrentRecord = 0;
       fNRecLevel++; // increase the nested level counter

       if(fNRecLevel<=kRecursiveModeMaxDepth) {
          LOG("GEVGDriver", pWARN)
            << "Attempting to regenerate the event...";
          return this->GenerateEvent(nu4p);
       } else {
          LOG("GEVGDriver", pERROR)
               << "Could not produce a physical event after "
                      << kRecursiveModeMaxDepth << " attempts!";
          delete fCurrentRecord;
          fCurrentRecord = 0;
          fNRecLevel = 0;
          return 0;
//        exit(1);
       }
     }
  }
}
//___________________________________________________________________________
const InteractionList * GEVGDriver::Interactions(void) const
{
// Returns the list of all interactions that can be generated by this driver

  if(!fIntGenMap) {
    LOG("GEVGDriver", pWARN)
       << "Interaction->Generator Map has not being built yet!";
    return 0;
  }

  const InteractionList & ilst = fIntGenMap->GetInteractionList();
  return &ilst;
}
//___________________________________________________________________________
void GEVGDriver::SetEventGeneratorList(string listname)
{
  LOG("GEVGDriver", pNOTICE)
       << "Setting event generator list: " << listname;

  fEventGenList = listname;
}
//___________________________________________________________________________
const EventGeneratorI *
  GEVGDriver::FindGenerator(const Interaction * interaction) const
{
  if(!interaction) {
    LOG("GEVGDriver", pWARN) << "Null interaction!!";
    return 0;
  }
  if(!fIntGenMap) {
    LOG("GEVGDriver", pWARN)
       << "Interaction->Generator Map has not being built yet!";
    return 0;
  }

  const EventGeneratorI * evgen = fIntGenMap->FindGenerator(interaction);
  return evgen;
}
//___________________________________________________________________________
double GEVGDriver::XSecSum(const TLorentzVector & nup4)
{
// Computes the sum of the cross sections for all the interactions that can
// be simulated for the given initial state and for the input neutrino energy
//
  LOG("GEVGDriver", pDEBUG) << "Computing the cross section sum";

  double xsec_sum = 0;

  // Get the list of spline objects
  // Should have been constructed at the job initialization
  XSecSplineList * xssl = XSecSplineList::Instance();

  // Get the list of all interactions that can be generated by this driver
  const InteractionList & ilst = fIntGenMap->GetInteractionList();

  // Loop over all interactions & compute cross sections
  InteractionList::const_iterator intliter;
  for(intliter = ilst.begin(); intliter != ilst.end(); ++intliter) {

     // get current interaction
     Interaction * interaction = new Interaction(**intliter);
     interaction->InitStatePtr()->SetProbeP4(nup4);

     string code = interaction->AsString();
     SLOG("GEVGDriver", pDEBUG)
             << "Compute cross section for interaction: \n" << code;

     // get corresponding cross section algorithm
     const XSecAlgorithmI * xsec_alg =
               fIntGenMap->FindGenerator(interaction)->CrossSectionAlg();
     assert(xsec_alg);

     // compute (or evaluate) the cross section
     double xsec = 0;
     bool spline_exists = xssl->SplineExists(xsec_alg, interaction);
     if (spline_exists && fUseSplines) {
        double E = nup4.Energy();
        xsec = xssl->GetSpline(xsec_alg,interaction)->Evaluate(E);
     } else
        xsec = xsec_alg->Integral(interaction);

     xsec = TMath::Max(0., xsec);

     // sum-up and report
     xsec_sum += xsec;
     LOG("GEVGDriver", pDEBUG)
            << "\nInteraction   = " << code
            << "\nCross Section "
            << (fUseSplines ? "*interpolated*" : "*computed*")
            << " = " << (xsec/units::cm2) << " cm2";

     delete interaction;
  } // loop over event generators

  PDGLibrary * pdglib = PDGLibrary::Instance();
  LOG("GEVGDriver", pINFO)
    << "SumXSec("
    << pdglib->Find(fInitState->ProbePdg())->GetName() << "+"
    << pdglib->Find(fInitState->Tgt().Pdg())->GetName() << "->X, "
    << "E = " << nup4.Energy() << " GeV)"
    << (fUseSplines ? "*interpolated*" : "*computed*")
    << " = " << (xsec_sum/units::cm2) << " cm2";

  return xsec_sum;
}
//___________________________________________________________________________
void GEVGDriver::CreateXSecSumSpline(
                               int nk, double Emin, double Emax, bool inlogE)
{
// This method creates a spline with the *total* cross section vs E (or logE)
// for the initial state that this driver was configured with.
// This spline is used, for example, by the GMCJDriver to select a target
// material out of all the materials in a detector geometry (summing the
// cross sections again and again proved to be expensive...)

  LOG("GEVGDriver", pINFO)
     << "Creating spline (sum-xsec = f(" << ((inlogE) ? "logE" : "E")
     << ") in E = [" << Emin << ", " << Emax << "] using " << nk << " knots";

  if(!fUseSplines) {
     LOG("GEVGDriver", pFATAL) << "You haven't loaded any splines!! ";
  }
  assert(fUseSplines);
  assert(Emin<Emax && Emin>0 && nk>2);

  double logEmin=0, logEmax=0, dE=0;

  double * E    = new double[nk];
  double * xsec = new double[nk];

  if(inlogE) {
    logEmin = TMath::Log(Emin);
    logEmax = TMath::Log(Emax);
    dE = (logEmax-logEmin)/(nk-1);
  } else {
    dE = (Emax-Emin)/(nk-1);
  }

  TLorentzVector p4(0,0,0,0);

  for(int i=0; i<nk; i++) {
    double e = (inlogE) ? TMath::Exp(logEmin + i*dE) : Emin + i*dE;
    p4.SetPxPyPzE(0.,0.,e,e);
    double xs = this->XSecSum(p4);

    E[i]    = e;
    xsec[i] = xs;
  }
  if (fXSecSumSpl) delete fXSecSumSpl;
  fXSecSumSpl = new Spline(nk, E, xsec);
  delete [] E;
  delete [] xsec;
}
//___________________________________________________________________________
const Spline * GEVGDriver::XSecSpline(const Interaction * interaction) const
{
// Returns the cross section spline for the input interaction as was
// computed from the cross section model associated with that interaction.

  if (!fUseSplines) return 0;

  // Get the list of spline objects
  // Should have been constructed at the job initialization
  XSecSplineList * xssl = XSecSplineList::Instance();

  // get corresponding cross section algorithm for the input interaction
  const XSecAlgorithmI * xsec_alg =
               fIntGenMap->FindGenerator(interaction)->CrossSectionAlg();
  assert(xsec_alg);

  const Spline * spl = xssl->GetSpline(xsec_alg,interaction);
  return spl;
}
//___________________________________________________________________________
void GEVGDriver::UseSplines(void)
{
// Instructs the driver to use cross section splines rather than computing
// cross sections by integrating the differential cross section model which
// can be very time-consuming.
// **Note**
// -- If you called GEVGDriver::CreateSplines() already the driver would
//    a) assume that you want to use them and b) would be assured that it
//    has all the splines it needs, so you do not need to call this method.
// -- If you populated the XSecSplineList in another way without this driver
//    knowing about it, eg from an external XML file, do call this method
//    to let the driver know that you want to use the splines. However, note
//    that the driver would **explicitly check** that you have loaded all the
//    splines it needs. If not, then its fiery personality will take over and
//    it will refuse your request, reverting back to not using splines.

  fUseSplines = true;

  // Get the list of spline objects
  // Should have been constructed at the job initialization
  XSecSplineList * xsl = XSecSplineList::Instance();

  // If the user wants to use splines, make sure that all the splines needed
  // have been computed or loaded
  if(fUseSplines) {

    // Get the list of all interactions that can be generated by this driver
    const InteractionList & ilst = fIntGenMap->GetInteractionList();

    // Loop over all interactions & check that all splines have been loaded
    InteractionList::const_iterator intliter;
    for(intliter = ilst.begin(); intliter != ilst.end(); ++intliter) {

       // current interaction
       Interaction * interaction = *intliter;

       // corresponding cross section algorithm
       const XSecAlgorithmI * xsec_alg =
                 fIntGenMap->FindGenerator(interaction)->CrossSectionAlg();
       assert(xsec_alg);

       // spline exists in spline list?
       bool spl_exists = xsl->SplineExists(xsec_alg, interaction);

       // update the 'use splines' flag
       fUseSplines = fUseSplines && spl_exists;

       if(!spl_exists) {
          if(!xsec_alg) {
            LOG("GEVGDriver", pWARN)
              << "Null cross-section algorithm! Can not load cross-section spline.";
            return;
          }
          if(!interaction) {
            LOG("GEVGDriver", pWARN)
              << "Null interaction! Can not load cross-section spline.";
            return;
          }
          LOG("GEVGDriver", pWARN)
             << "*** At least a spline (algorithm: "
             << xsec_alg->Id().Key() << ", interaction: "
             << interaction->AsString() << " doesn't exist. "
             << "Reverting back to not using splines";
          return;
       }
     } // loop over interaction list
  }//use-splines?
}
//___________________________________________________________________________
void GEVGDriver::CreateSplines(int nknots, double emax, bool useLogE)
{
// Creates all the cross section splines that are needed by this driver.
// It will check for pre-loaded splines and it will skip the creation of the
// splines it already finds loaded.

  LOG("GEVGDriver", pINFO)
       << "Creating (missing) splines with [UseLogE: "
                                             << ((useLogE) ? "ON]" : "OFF]");
  // Get the list of spline objects
  XSecSplineList * xsl = XSecSplineList::Instance();
  xsl->SetLogE(useLogE);

  EventGeneratorList::const_iterator evgliter; // event generator list iter
  InteractionList::iterator          intliter; // interaction list iter

  // loop over all EventGenerator objects used in the current job
  for(evgliter = fEvGenList->begin();
                               evgliter != fEvGenList->end(); ++evgliter) {
     // current event generator
     const EventGeneratorI * evgen = *evgliter;
     LOG("GEVGDriver", pINFO)
            << "Querying [" << evgen->Id().Key()
                                            << "] for its InteractionList";

     // ask the event generator to produce a list of all interaction it can
     // generate for the input initial state
     const InteractionListGeneratorI * ilstgen = evgen->IntListGenerator();
     InteractionList * ilst = ilstgen->CreateInteractionList(*fInitState);
     if(!ilst) continue;

     // total cross section algorithm used by the current EventGenerator
     const XSecAlgorithmI * alg = evgen->CrossSectionAlg();

     // get the energy range of the spline from the EventGenerator
     // validity context
     double Emin = TMath::Max(0.001,evgen->ValidityContext().Emin());
     double Emax = evgen->ValidityContext().Emax();

     // if the user set a maximum energy, create the spline up to this
     // energy - otherwise use the upper limit of the validity range of
     // the current generator
     if ( emax > 0 ) {
       if ( emax > Emax ) {
         LOG("GEVGDriver", pWARN)
           << "Refusing to exceed validity range: Emax = " << Emax;
       }
       emax = TMath::Min(emax,Emax); // don't exceed validity range
     } else {
       emax = Emax;
     }

     assert( emax > Emin );

     // number of knots: use specified number. If not set, use 15 knots
     // per decade. Don't use less than 30 knots.
     if ( nknots < 0 ) {
       nknots = (int) (15 * TMath::Log10(emax-Emin));
     }
     nknots = TMath::Max(nknots,30);

     // loop over all interactions that can be generated and ask the
     // appropriate cross section algorithm to compute its cross section
     for(intliter = ilst->begin(); intliter != ilst->end(); ++intliter) {

         // current interaction
         Interaction * interaction = *intliter;
         string code = interaction->AsString();

         SLOG("GEVGDriver", pINFO) << "Need xsec spline for " << code;

         // only create the spline if it does not already exists
         bool spl_exists = xsl->SplineExists(alg, interaction);
         if(!spl_exists) {
             SLOG("GEVGDriver", pDEBUG)
               << "The spline wasn't loaded at initialization. "
               << "I can build it now but it might take a while...";
             xsl->CreateSpline(alg, interaction, nknots, Emin, emax);
         } else {
             SLOG("GEVGDriver", pDEBUG) << "Spline was found";
         }
     } // loop over interaction that can be generated by this generator
     delete ilst;
     ilst = 0;
  } // loop over event generators

  LOG("GEVGDriver", pINFO) << *xsl; // print list of splines

  fUseSplines = true;
}
//___________________________________________________________________________
Range1D_t GEVGDriver::ValidEnergyRange(void) const
{
// loops over all loaded event generation threads, queries for the energy
// range at their validity context and builds the valid energy range for
// this driver

  Range1D_t E;
  E.min =  9999;
  E.max = -9999;

  EventGeneratorList::const_iterator evgliter; // event generator list iter

  // loop over all EventGenerator objects used in the current job
  for(evgliter = fEvGenList->begin();
                               evgliter != fEvGenList->end(); ++evgliter) {
     // current event generator
     const EventGeneratorI * evgen = *evgliter;

     // Emin, Emax as declared in current generator's validity context
     double Emin = TMath::Max(0.001,evgen->ValidityContext().Emin());
     double Emax = evgen->ValidityContext().Emax();

     // combined Emin, Emax
     E.min = TMath::Min(E.min, Emin);
     E.max = TMath::Max(E.max, Emax);
  }
  assert(E.min<E.max && E.min>=0);
  return E;
}
//___________________________________________________________________________
void GEVGDriver::AssertIsValidInitState(void) const
{
  assert(fInitState);
  int ppdgc = fInitState->ProbePdg();
  bool isv = pdg::IsLepton(ppdgc) || pdg::IsDarkMatter(ppdgc);
  assert(isv);
}
//___________________________________________________________________________
void GEVGDriver::Print(ostream & stream) const
{
  stream
    << "\n\n *********************** GEVGDriver ***************************";

  int ppdg   = fInitState->ProbePdg();
  int tgtpdg = fInitState->Tgt().Pdg();

  stream << "\n  |---o Probe PDG-code ......: " << ppdg;
  stream << "\n  |---o Target PDG-code .....: " << tgtpdg;

  stream << "\n  |---o Using cross section splines is turned "
                                << utils::print::BoolAsIOString(fUseSplines);
  stream << "\n  |---o Unphysical event filter mask ("
         << GHepFlags::NFlags() << "->0) = " << *fUnphysEventMask;

  stream << "\n *********************************************************\n";
}
//___________________________________________________________________________