HepMCHelper.icc

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/*
  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
*/
 
// STL includes
#include <set>
 
// @TODO: probably replace this by an enum some day
#define ISF_UNDEF_CHARGE -99999.
 
#include "AtlasHepMC/GenEvent.h"
#include "AtlasHepMC/IteratorRange.h"
#include "AtlasHepMC/Relatives.h"
/** constructor */
ISF::HepMCHelper::HepMCHelper() {
}
 
/** emtpy destructor */
ISF::HepMCHelper::~HepMCHelper() {
}
 
 
HepMC::IteratorRange ISF::HepMCHelper::convertIteratorRange( int intItRange ) {
  if      (intItRange==0) return ( HepMC::parents   );
  else if (intItRange==1) return ( HepMC::family    );
  else if (intItRange==2) return ( HepMC::ancestors );
  else if (intItRange==3) return ( HepMC::relatives );
  else                    return ( HepMC::parents   );
}
 
#ifdef HEPMC3
HepMC::ConstGenParticlePtr ISF::HepMCHelper::findRealtiveWithPDG( HepMC::ConstGenParticlePtr& genParticle,
        const HepMC::IteratorRange &relation,
        const std::set<int> &relativesPDG     ) {
    // get range of relative particles
    std::vector<HepMC::ConstGenParticlePtr> relativesRng;
    switch(relation) {
    case  HepMC::parents:                   {
        if (genParticle->production_vertex()) relativesRng= genParticle->production_vertex()->particles_in();
        break;
    }
    case  HepMC::family:                    {
        if (genParticle->production_vertex()) relativesRng= genParticle->production_vertex()->particles_in();
        std::vector<HepMC::ConstGenParticlePtr> temp;
        if (genParticle->end_vertex()) temp=genParticle->end_vertex()->particles_out();
        relativesRng.insert(relativesRng.end(),temp.begin(),temp.end());
        break;
    }
    case  HepMC::ancestors:                 {
        relativesRng= HepMC::ancestor_particles(genParticle);
        break;
    }
    case  HepMC::relatives:               {
        relativesRng= HepMC::ancestor_particles(genParticle);
        std::vector<HepMC::ConstGenParticlePtr> temp=HepMC::descendant_particles(genParticle);
        relativesRng.insert(relativesRng.end(),temp.begin(),temp.end());
        break;
    }
    default:                            {
        if (genParticle->production_vertex()) relativesRng= genParticle->production_vertex()->particles_in();
        break;
    }
    }
    // loop over relatives
    for (auto curRelative:  relativesRng)  {
        if (relativesPDG.count( curRelative->pdg_id() ) != 0) return curRelative;
    }
 
    return nullptr;
}
#else
HepMC::ConstGenParticlePtr ISF::HepMCHelper::findRealtiveWithPDG( HepMC::ConstGenParticlePtr& genParticle,
                                                                  const HepMC::IteratorRange &relation,
                                                                  const std::set<int> &relativesPDG     ) {
 
  if (!genParticle) return 0;
  // get range of relative particles
  HepMC::ConstGenParticleProductionRange relativesRng = genParticle->particles_in( relation );
 
  // loop over relatives
  HepMC::GenVertex::particle_iterator       partIt  = relativesRng.begin();
  const HepMC::GenVertex::particle_iterator partEnd = relativesRng.end();
  HepMC::ConstGenParticlePtr curRelative{};
  bool  found = false;
  for ( ; (!found) && (partIt!=partEnd) ; ++partIt) {
    curRelative = (*partIt) ;
    // check if current relative particle PDG ID is found in the set
    found = relativesPDG.count( curRelative->pdg_id() ) != 0;
  }
 
  return (found ? curRelative : 0);
}
#endif