InputConverter.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
// class header include
#include "InputConverter.h"
 
#include <memory>
 
// framework
#include "GaudiKernel/IPartPropSvc.h"
#include "GaudiKernel/PhysicalConstants.h"
 
// ISF_HepMC include
#include "ISF_Event/TruthBinding.h"
#include "ISF_HepMC_Interfaces/IGenParticleFilter.h"
// ISF_Event include
#include "ISF_Event/ISFParticle.h"
#include "ISF_Event/ISFParticleContainer.h"
#include "ISF_Event/ISFParticleContainer.h"
#include "ISF_Event/ParticleUserInformation.h"
// MCTruth includes
#include "MCTruth/PrimaryParticleInformation.h"
#include "MCTruth/AtlasG4EventUserInfo.h"
// McEventCollection
#include "GeneratorObjects/McEventCollection.h"
// Geant4 includes
#include "G4PrimaryParticle.hh"
#include "G4Event.hh"
#include "G4Geantino.hh"
#include "G4ChargedGeantino.hh"
#include "G4ParticleTable.hh"
#include "G4LorentzVector.hh"
#include "G4TransportationManager.hh"
// HepMC includes
#include "AtlasHepMC/GenParticle.h"
#include "AtlasHepMC/GenEvent.h"
#include "AtlasHepMC/GenVertex.h"
// CLHEP includes
#include "CLHEP/Geometry/Point3D.h"
#include "CLHEP/Geometry/Vector3D.h"
#include "CLHEP/Units/SystemOfUnits.h"
// HepPDT
#include "HepPDT/ParticleID.hh"
#include "HepPDT/DecayData.hh"
#include "HepPDT/ParticleDataTable.hh"
#include "TruthUtils/HepMCHelpers.h"
 
ISF::InputConverter::InputConverter(const std::string& name, ISvcLocator* svc)
  : base_class(name, svc)
  , m_particlePropSvc("PartPropSvc",name)
  , m_particleDataTable(nullptr)
  , m_useGeneratedParticleMass(false)
  , m_genParticleFilters(this)
  , m_quasiStableParticlesIncluded(false)
{
  // particle mass from particle data table?
  declareProperty("UseGeneratedParticleMass",
                  m_useGeneratedParticleMass,
                  "Use particle mass assigned to GenParticle.");
  // particle filters
  declareProperty("GenParticleFilters",
                  m_genParticleFilters,
                  "Tools for filtering out GenParticles.");
  // the particle property service
  declareProperty("ParticlePropertyService",
                  m_particlePropSvc,
                  "ParticlePropertyService to retrieve the PDT.");
  declareProperty("QuasiStableParticlesIncluded", m_quasiStableParticlesIncluded);
}
 
 
ISF::InputConverter::~InputConverter()
{
}
 
 
// Athena algtool's Hooks
StatusCode
ISF::InputConverter::initialize()
{
  ATH_MSG_VERBOSE("initialize() begin");
 
  // setup PDT if requested (to get particle masses later on)
  if (!m_useGeneratedParticleMass) {
    ATH_CHECK(m_particlePropSvc.retrieve());
    m_particleDataTable = m_particlePropSvc->PDT();
    if (!m_particleDataTable) {
      ATH_MSG_FATAL( "Could not get ParticleDataTable from " << m_particlePropSvc << ". Abort" );
      return StatusCode::FAILURE;
    }
  }
 
  if (!m_genParticleFilters.empty()) {
    ATH_CHECK(m_genParticleFilters.retrieve());
  }
 
  ATH_MSG_VERBOSE("initialize() successful");
  return StatusCode::SUCCESS;
}
 
 
StatusCode
ISF::InputConverter::finalize()
{
  ATH_MSG_DEBUG("Finalizing ...");
  return StatusCode::SUCCESS;
}
 
 
StatusCode
ISF::InputConverter::convert(McEventCollection& inputGenEvents,
                             ISF::ISFParticleContainer& simParticles) const
{
  for ( auto eventPtr : inputGenEvents ) {
    // skip empty events
    if (eventPtr == nullptr) { continue; }
 
    ATH_MSG_DEBUG("Starting conversion of GenEvent with"
                  " signal_process_id=" << HepMC::signal_process_id(eventPtr) <<
                  " and event_number=" << eventPtr->event_number() );
 
    // new collection containing all gen particles that passed filters
    bool legacyOrdering = true; // FIXME: this is only to keep the same order of particles
                                //        as the prior 'StackFiller' implementation
                                // TODO:  remove this functionality from the
                                //        getSelectedParticles function once
                                //        happy with the results
    const auto passedGenParticles = getSelectedParticles(*eventPtr, legacyOrdering);
 
    for ( auto& genPartPtr : passedGenParticles ) {
      ATH_MSG_VERBOSE("Picking up following GenParticle for conversion to ISFParticle: " <<  genPartPtr);
      auto simParticlePtr = convertParticle(genPartPtr);
      if (!simParticlePtr) {
        ATH_MSG_ERROR("Error while trying to convert input generator particles. Aborting.");
        return StatusCode::FAILURE;
      }
      // add to collection that will be returned
      simParticles.push_back(simParticlePtr);
 
    } // loop over passed gen particles
 
  } // loop over gen events
 
  ATH_MSG_DEBUG( "Created initial simulation particle collection with size " << simParticles.size() );
 
  return StatusCode::SUCCESS;
}
 
StatusCode ISF::InputConverter::convertHepMCToG4Event(McEventCollection& inputGenEvents,
                                                      G4Event*& outputG4Event, McEventCollection& shadowGenEvents) const
{
  ISF::ISFParticleContainer simParticleList{}; // particles for ISF simulation
  ATH_CHECK(this->convert(inputGenEvents, simParticleList));
  //Convert from ISFParticleContainer to ConstISFParticleVector
  ISF::ISFParticleVector simParticleVector{
    std::make_move_iterator(std::begin(simParticleList)),
      std::make_move_iterator(std::end(simParticleList))
      };
  if (!shadowGenEvents.empty()) {
    outputG4Event = this->ISF_to_G4Event(simParticleVector, inputGenEvents.back(), shadowGenEvents.back());
  }
  else{
    outputG4Event = this->ISF_to_G4Event(simParticleVector, inputGenEvents.back(), nullptr);
  }
  return StatusCode::SUCCESS;
}
 
 
StatusCode ISF::InputConverter::convertHepMCToG4EventLegacy(McEventCollection& inputGenEvents,
                                                            G4Event*& outputG4Event) const
{
  ISF::ISFParticleContainer simParticleList{}; // particles for ISF simulation
  ATH_CHECK(this->convert(inputGenEvents, simParticleList));
  //Convert from ISFParticleContainer to ConstISFParticleVector
  ISF::ISFParticleVector simParticleVector{
    std::make_move_iterator(std::begin(simParticleList)),
      std::make_move_iterator(std::end(simParticleList))
      };
  outputG4Event = this->ISF_to_G4Event(simParticleVector, inputGenEvents.back(), nullptr);
  return StatusCode::SUCCESS;
}
 
 
#ifdef HEPMC3
std::vector<HepMC::GenParticlePtr>
ISF::InputConverter::getSelectedParticles(HepMC::GenEvent& evnt, bool legacyOrdering) const {
  auto allGenPartBegin = evnt.particles().begin();
  auto allGenPartEnd = evnt.particles().end();
 
  // reserve destination container with maximum size, i.e. number of particles in input event
  std::vector<HepMC::GenParticlePtr> passedGenParticles{};
  size_t maxParticles = std::distance(allGenPartBegin, allGenPartEnd);
  passedGenParticles.reserve(maxParticles);
 
  if (m_useShadowEvent) {
    if (legacyOrdering) {
      // FIXME: remove this block and the 'legacyOrdering' flag
      //        once we don't need the legacy order any longer
      for (auto vtx: evnt.vertices() ) {
        std::copy_if (vtx->particles_out().begin(),
                      vtx->particles_out().end(),
                      std::back_inserter(passedGenParticles),
                      [](HepMC::GenParticlePtr p){return p->attribute<HepMC3::IntAttribute>("ShadowParticleId");});
      }
    }
    else {
      std::copy_if (allGenPartBegin,
                    allGenPartEnd,
                    std::back_inserter(passedGenParticles),
                    [](HepMC::GenParticlePtr p){return p->attribute<HepMC3::IntAttribute>("ShadowParticleId");});
    }
  }
  else {
    if (legacyOrdering) {
      // FIXME: remove this block and the 'legacyOrdering' flag
      //        once we don't need the legacy order any longer
      for (auto vtx: evnt.vertices() ) {
        std::copy_if (vtx->particles_out().begin(),
                      vtx->particles_out().end(),
                      std::back_inserter(passedGenParticles),
                      [this](HepMC::GenParticlePtr p){return this->passesFilters(std::const_pointer_cast<const HepMC3::GenParticle>(p));});
      }
    }
    else {
      std::copy_if (allGenPartBegin,
                    allGenPartEnd,
                    std::back_inserter(passedGenParticles),
                    [this](HepMC::GenParticlePtr p){return this->passesFilters(std::const_pointer_cast<const HepMC3::GenParticle>(p));});
    }
  }
 
  passedGenParticles.shrink_to_fit();
 
  return passedGenParticles;
}
#else
std::vector<HepMC::GenParticlePtr>
ISF::InputConverter::getSelectedParticles(HepMC::GenEvent& evnt, bool legacyOrdering) const {
  auto allGenPartBegin = evnt.particles_begin();
  auto allGenPartEnd = evnt.particles_end();
 
  // reserve destination container with maximum size, i.e. number of particles in input event
  std::vector<HepMC::GenParticlePtr> passedGenParticles{};
  size_t maxParticles = std::distance(allGenPartBegin, allGenPartEnd);
  passedGenParticles.reserve(maxParticles);
 
  if (legacyOrdering) {
    // FIXME: remove this block and the 'legacyOrdering' flag
    //        once we don't need the legacy order any longer
    auto vtxIt = evnt.vertices_begin();
    auto vtxItEnd = evnt.vertices_end();
    for ( ; vtxIt != vtxItEnd; ++vtxIt ) {
      const auto vtxPtr = *vtxIt;
      std::copy_if (vtxPtr->particles_begin(HepMC::children),
                    vtxPtr->particles_end(HepMC::children),
                    std::back_inserter(passedGenParticles),
                    [this](HepMC::GenParticlePtr p){return this->passesFilters(*p);});
    }
  }
  else {
    std::copy_if (allGenPartBegin,
                  allGenPartEnd,
                  std::back_inserter(passedGenParticles),
                  [this](HepMC::GenParticlePtr p){return this->passesFilters(*p);});
  }
 
  passedGenParticles.shrink_to_fit();
 
  return passedGenParticles;
}
#endif
 
 
ISF::ISFParticle*
ISF::InputConverter::convertParticle(const HepMC::GenParticlePtr& genPartPtr) const {
  if (!genPartPtr) { return nullptr; }
 
  auto  pVertex = genPartPtr->production_vertex();
  if (!pVertex) {
    ATH_MSG_ERROR("Unable to convert following generator particle due to missing production vertex for: " << genPartPtr);
    return nullptr;
  }
  auto parentEvent = genPartPtr->parent_event();
  if (!parentEvent) {
    ATH_MSG_ERROR("Cannot convert a GenParticle without a parent GenEvent into an ISFParticle!!!");
    return nullptr;
  }
 
  const Amg::Vector3D pos(pVertex->position().x(), pVertex->position().y(), pVertex->position().z());
  const auto& pMomentum(genPartPtr->momentum());
  const Amg::Vector3D mom(pMomentum.px(), pMomentum.py(), pMomentum.pz());
#ifdef HEPMC3
  const double pMass = this->getParticleMass(genPartPtr);
#else
  const double pMass = this->getParticleMass(*genPartPtr);
#endif
  double e=pMomentum.e();
  if (e>1) { //only test for >1 MeV in momentum
    double px=pMomentum.px();
    double py=pMomentum.py();
    double pz=pMomentum.pz();
    double teste=std::sqrt(px*px + py*py + pz*pz + pMass*pMass);
    if (std::abs(e-teste)>0.01*e) {
      ATH_MSG_WARNING("Difference in energy for: " << genPartPtr<<" Morg="<<pMomentum.m()<<" Mmod="<<pMass<<" Eorg="<<e<<" Emod="<<teste);
    }
    if (MC::isDecayed(genPartPtr) && pVertex && genPartPtr->end_vertex()) { //check for possible changes of gamma for quasi stable particles
      const auto& prodVtx = genPartPtr->production_vertex()->position();
      const auto& endVtx = genPartPtr->end_vertex()->position();
      CLHEP::Hep3Vector dist3D(endVtx.x()-prodVtx.x(), endVtx.y()-prodVtx.y(), endVtx.z()-prodVtx.z());
 
      if (dist3D.mag()>1*Gaudi::Units::mm) {
        CLHEP::HepLorentzVector mom( pMomentum.x(), pMomentum.y(), pMomentum.z(), pMomentum.t() );
        double gamma_org=mom.gamma();
        mom.setE(teste);
        double gamma_new=mom.gamma();
 
        if (std::abs(gamma_new-gamma_org)/(gamma_new+gamma_org)>0.001) {
          ATH_MSG_WARNING("Difference in boost gamma for Quasi stable particle "<<genPartPtr);
          ATH_MSG_WARNING("  gamma(m="<<mom.m()<<")="<<gamma_org<<" gamma(m="<<pMass<<")="<<gamma_new);
        } else {
          ATH_MSG_VERBOSE("Quasi stable particle "<<genPartPtr);
          ATH_MSG_VERBOSE("  gamma(m="<<mom.m()<<")="<<gamma_org<<" gamma(m="<<pMass<<")="<<gamma_new);
        }
      }
    }
  }
 
  const int pPdgId = genPartPtr->pdg_id();
  const double charge = HepPDT::ParticleID(pPdgId).charge();
  const double pTime = pVertex->position().t() / Gaudi::Units::c_light;
  DetRegionSvcIDPair origin(AtlasDetDescr::fUndefinedAtlasRegion, ISF::fEventGeneratorSimID);
  const auto pBarcode = HepMC::barcode(genPartPtr);
  const auto particleID = HepMC::uniqueID(genPartPtr);
  auto tBinding = std::make_unique<ISF::TruthBinding>(genPartPtr);
 
  auto hmpl = std::make_unique<HepMcParticleLink>(particleID, parentEvent->event_number(), HepMcParticleLink::IS_EVENTNUM, HepMcParticleLink::IS_ID);
 
  auto sParticle = std::make_unique<ISF::ISFParticle>( std::move(pos),
                                                       std::move(mom),
                                                       pMass,
                                                       charge,
                                                       pPdgId,
                                                       genPartPtr->status(),
                                                       pTime,
                                                       origin,
                                                       particleID,
                                                       pBarcode,
                                                       tBinding.release(),
                                                       hmpl.release() );
  return sParticle.release();
}
 
 
#ifdef HEPMC3
double
ISF::InputConverter::getParticleMass(const HepMC::ConstGenParticlePtr& part) const{
  // default value: generated particle mass
  double mass = part->generated_mass();
  ATH_MSG_VERBOSE("part->generated_mass, mass="<<mass);
 
  // 1. use PDT mass?
  if ( !m_useGeneratedParticleMass ) {
    const int absPDG = std::abs(part->pdg_id());
    HepPDT::ParticleData const *pData = (m_particleDataTable)
      ? m_particleDataTable->particle(absPDG)
      : nullptr;
    if (pData) {
      mass = pData->mass();
      ATH_MSG_VERBOSE("using pData mass, mass="<<mass);
    }
    else {
      ATH_MSG_WARNING( "Unable to find mass of particle with PDG ID '" << absPDG << "' in ParticleDataTable. Will set mass to generated_mass: " << mass);
    }
  }
  return mass;
}
#else
double
ISF::InputConverter::getParticleMass(const HepMC::GenParticle &part) const
{
  // default value: generated particle mass
  double mass = part.generated_mass();
  ATH_MSG_VERBOSE("part.generated_mass, mass="<<mass);
 
  // 1. use PDT mass?
  if ( !m_useGeneratedParticleMass ) {
    const int absPDG = std::abs(part.pdg_id());
    HepPDT::ParticleData const *pData = (m_particleDataTable)
      ? m_particleDataTable->particle(absPDG)
      : nullptr;
    if (pData) {
      mass = pData->mass();
      ATH_MSG_VERBOSE("using pData mass, mass="<<mass);
    }
    else {
      ATH_MSG_WARNING( "Unable to find mass of particle with PDG ID '" << absPDG << "' in ParticleDataTable. Will set mass to generated_mass: " << mass);
    }
  }
  return mass;
}
#endif
 
 
#ifdef HEPMC3
bool
ISF::InputConverter::passesFilters(const HepMC::ConstGenParticlePtr& part) const
{
  // TODO: implement this as a std::find_if with a lambda function
  for ( const auto& filter : m_genParticleFilters ) {
    // determine if the particle passes current filter
    bool passFilter = filter->pass(part);
    ATH_MSG_VERBOSE("GenParticleFilter '" << filter.typeAndName() << "' returned: "
                    << (passFilter ? "true, will keep particle."
                        : "false, will remove particle."));
    const auto& momentum = part->momentum();
    ATH_MSG_VERBOSE("Particle: ("
                    <<momentum.px()<<", "
                    <<momentum.py()<<", "
                    <<momentum.pz()<<"), pdgCode: "
                    <<part->pdg_id() );
 
    if (!passFilter) {
      return false;
    }
  }
 
  return true;
}
#else
bool
ISF::InputConverter::passesFilters(const HepMC::GenParticle& part) const
{
  // TODO: implement this as a std::find_if with a lambda function
  for ( const auto& filter : m_genParticleFilters ) {
    // determine if the particle passes current filter
    bool passFilter = filter->pass(part);
    ATH_MSG_VERBOSE("GenParticleFilter '" << filter.typeAndName() << "' returned: "
                    << (passFilter ? "true, will keep particle."
                        : "false, will remove particle."));
    const auto& momentum = part.momentum();
    ATH_MSG_VERBOSE("Particle: ("
                    <<momentum.px()<<", "
                    <<momentum.py()<<", "
                    <<momentum.pz()<<"), pdgCode: "
                    <<part.pdg_id() );
 
    if (!passFilter) {
      return false;
    }
  }
 
  return true;
}
#endif
 
 
//________________________________________________________________________
G4Event* ISF::InputConverter::ISF_to_G4Event(const ISF::ISFParticleVector& ispVector, HepMC::GenEvent *genEvent, HepMC::GenEvent *shadowGenEvent, bool useHepMC) const
{
  const int eventID(1);
  G4Event *g4evt = new G4Event(eventID);
 
  // retrieve world solid (volume)
  const G4VSolid *worldSolid = G4TransportationManager::GetTransportationManager()->GetNavigatorForTracking()->GetWorldVolume()->GetLogicalVolume()->GetSolid();
 
  for ( ISF::ISFParticle *ispPtr: ispVector ) {
    ISF::ISFParticle &isp = *ispPtr;
    if ( !isInsideG4WorldVolume(isp, worldSolid) ) {
      ATH_MSG_WARNING("Unable to convert ISFParticle to G4PrimaryParticle!");
      ATH_MSG_WARNING(" ISFParticle: " << isp );
      if (worldSolid) {
        ATH_MSG_WARNING(" is outside Geant4 world volume: ");
        worldSolid->DumpInfo();
        G4cout << std::flush;
      }
      else {
        ATH_MSG_WARNING(" is outside Geant4 world volume.");
      }
      continue;
    }
    this->addG4PrimaryVertex(g4evt,isp,useHepMC,shadowGenEvent);
  }
 
  AtlasG4EventUserInfo *atlasG4EvtUserInfo=new AtlasG4EventUserInfo();
  atlasG4EvtUserInfo->SetLastProcessedTrackID(0); // TODO Check if it is better to set this to -1 initially
  atlasG4EvtUserInfo->SetLastProcessedStep(0); // TODO Check if it is better to set this to -1 initially
  atlasG4EvtUserInfo->SetHepMCEvent(genEvent);
  g4evt->SetUserInformation(atlasG4EvtUserInfo);
 
  return g4evt;
}
 
//________________________________________________________________________
const G4ParticleDefinition* ISF::InputConverter::getG4ParticleDefinition(int pdgcode) const
{
  if (pdgcode==998) {
    return G4ChargedGeantino::Definition();
  }
  if (pdgcode==999) {
    return G4Geantino::GeantinoDefinition();
  }
  G4ParticleTable *ptable = G4ParticleTable::GetParticleTable();
  if (ptable) {
    return ptable->FindParticle(pdgcode);
  }
  ATH_MSG_ERROR("getG4ParticleDefinition - Failed to retrieve G4ParticleTable!");
  return nullptr;
}
 
double SetProperTimeFromDetectorFrameDecayLength(G4PrimaryParticle& g4particle,const double GeneratorDecayLength)
{
  //particle with velocity v travels distance l in time t=l/v
  //proper time: c^2 tau^2 = c^2 t^2 - l^2 = l^2/c^2 * (1/beta^2 -1)
  //beta^2 = p^2/E^2 with particle momentum p and energy E; E^2=m^2 + p^2
  //tau^2 = l^2/c^2 * m^2/p^2
  const double p2=std::pow(g4particle.GetTotalMomentum(),2); //magnitude of particle momentum squared
  const double m2=std::pow(g4particle.GetMass(),2);          //mass^2 of particle
  const double l2=std::pow(GeneratorDecayLength,2);          //distance^2 of particle decay length
  const double tau2=l2*m2/p2/CLHEP::c_squared;
  const double tau=std::sqrt(tau2);
  g4particle.SetProperTime( tau );
  return tau;
}
 
//________________________________________________________________________
#ifdef HEPMC3
G4PrimaryParticle* ISF::InputConverter::getDaughterG4PrimaryParticle(const HepMC::GenParticlePtr& genpart, bool makeLinkToTruth) const{
  ATH_MSG_VERBOSE("Creating G4PrimaryParticle from GenParticle.");
 
  const G4ParticleDefinition *particleDefinition = this->getG4ParticleDefinition(genpart->pdg_id());
 
  if (particleDefinition==nullptr) {
    ATH_MSG_ERROR("ISF_to_G4Event particle conversion failed. ISF_Particle PDG code = " << genpart->pdg_id() <<
                  "\n This usually indicates a problem with the evgen step.\n" <<
                  "Please report this to the Generators group, mentioning the release and generator used for evgen and the PDG code above." );
    return nullptr;
  }
 
  // create new primaries and set them to the vertex
  //  G4double mass =  particleDefinition->GetPDGMass();
  auto &genpartMomentum = genpart->momentum();
  G4double px = genpartMomentum.x();
  G4double py = genpartMomentum.y();
  G4double pz = genpartMomentum.z();
 
  std::unique_ptr<G4PrimaryParticle> g4particle = std::make_unique<G4PrimaryParticle>(particleDefinition,px,py,pz);
 
  if (genpart->end_vertex()) {
    // Set the lifetime appropriately - this is slow but rigorous, and we
    //  don't want to end up with something like vertex time that we have
    //  to validate for every generator on earth...
    const auto& prodVtx = genpart->production_vertex()->position();
    const auto& endVtx = genpart->end_vertex()->position();
    //const G4LorentzVector lv0 ( prodVtx.x(), prodVtx.y(), prodVtx.z(), prodVtx.t() );
    //const G4LorentzVector lv1 ( endVtx.x(), endVtx.y(), endVtx.z(), endVtx.t() );
    //Old calculation, not taken because vertex information is not sufficiently precise
    //g4particle->SetProperTime( (lv1-lv0).mag()/Gaudi::Units::c_light );
 
    CLHEP::Hep3Vector dist3D(endVtx.x()-prodVtx.x(), endVtx.y()-prodVtx.y(), endVtx.z()-prodVtx.z());
    double tau=SetProperTimeFromDetectorFrameDecayLength(*g4particle,dist3D.mag());
 
    if (msgLvl(MSG::VERBOSE)) {
      double pmag2=g4particle->GetTotalMomentum(); //magnitude of particle momentum
      pmag2*=pmag2;                                //magnitude of particle momentum squared
      double e2=g4particle->GetTotalEnergy();      //energy of particle
      e2*=e2;                                      //energy of particle squared
      double beta2=pmag2/e2;                       //beta^2=v^2/c^2 for particle
      double tau2=dist3D.mag2()*(1/beta2-1)/Gaudi::Units::c_light/Gaudi::Units::c_light;
      ATH_MSG_VERBOSE("lifetime tau(beta)="<<std::sqrt(tau2)<<" tau="<<tau);
    }
    if (m_quasiStableParticlesIncluded) {
      ATH_MSG_VERBOSE( "Detected primary particle with end vertex." );
      ATH_MSG_VERBOSE( "Will add the primary particle set on." );
      ATH_MSG_VERBOSE( "Primary Particle: " << genpart );
      ATH_MSG_VERBOSE( "Number of daughters: " << genpart->end_vertex()->particles_out().size()<<" at position "<<genpart->end_vertex() );
    }
    else {
      ATH_MSG_WARNING( "Detected primary particle with end vertex." );
      ATH_MSG_WARNING( "Will add the primary particle set on." );
      ATH_MSG_WARNING( "Primary Particle: " << genpart );
      ATH_MSG_WARNING( "Number of daughters : " << genpart->end_vertex()->particles_out().size()<<" at position "<<genpart->end_vertex() );
    }
    // Add all necessary daughter particles
    for ( auto daughter: genpart->end_vertex()->particles_out() ) {
      if (m_quasiStableParticlesIncluded) {
        ATH_MSG_VERBOSE ( "Attempting to add daughter particle : " << daughter );
      }
      else {
        ATH_MSG_WARNING ( "Attempting to add daughter particle: " << daughter );
      }
      G4PrimaryParticle *daughterG4Particle = this->getDaughterG4PrimaryParticle( daughter, makeLinkToTruth );
      if (!daughterG4Particle) {
        ATH_MSG_ERROR("Bailing out of loop over daughters of particle: "<<
                      " due to errors - will not return G4Particle.");
        return nullptr;
      }
      g4particle->SetDaughter( daughterG4Particle );
    }
  }
 
  if (makeLinkToTruth) {
    // Set the user information for this primary to point to the HepMcParticleLink...
    std::unique_ptr<PrimaryParticleInformation> primaryPartInfo = std::make_unique<PrimaryParticleInformation>(genpart);
    primaryPartInfo->SetRegenerationNr(0);
    g4particle->SetUserInformation(primaryPartInfo.release());
    ATH_MSG_VERBOSE("Making primary down the line with barcode " << primaryPartInfo->GetParticleUniqueID());
  }
 
  return g4particle.release();
}
 
//________________________________________________________________________
G4PrimaryParticle* ISF::InputConverter::getDaughterG4PrimaryParticle(const HepMC::ConstGenParticlePtr& genpart) const{
  ATH_MSG_VERBOSE("Creating G4PrimaryParticle from GenParticle.");
 
  const G4ParticleDefinition *particleDefinition = this->getG4ParticleDefinition(genpart->pdg_id());
 
  if (particleDefinition==nullptr) {
    ATH_MSG_ERROR("ISF_to_G4Event particle conversion failed. ISF_Particle PDG code = " << genpart->pdg_id() <<
                  "\n This usually indicates a problem with the evgen step.\n" <<
                  "Please report this to the Generators group, mentioning the release and generator used for evgen and the PDG code above." );
    return nullptr;
  }
 
  // create new primaries and set them to the vertex
  //  G4double mass =  particleDefinition->GetPDGMass();
  auto &genpartMomentum = genpart->momentum();
  G4double px = genpartMomentum.x();
  G4double py = genpartMomentum.y();
  G4double pz = genpartMomentum.z();
 
  std::unique_ptr<G4PrimaryParticle> g4particle = std::make_unique<G4PrimaryParticle>(particleDefinition,px,py,pz);
 
  if (genpart->end_vertex()) {
    // Set the lifetime appropriately - this is slow but rigorous, and we
    //  don't want to end up with something like vertex time that we have
    //  to validate for every generator on earth...
    const auto& prodVtx = genpart->production_vertex()->position();
    const auto& endVtx = genpart->end_vertex()->position();
    //const G4LorentzVector lv0 ( prodVtx.x(), prodVtx.y(), prodVtx.z(), prodVtx.t() );
    //const G4LorentzVector lv1 ( endVtx.x(), endVtx.y(), endVtx.z(), endVtx.t() );
    //Old calculation, not taken because vertex information is not sufficiently precise
    //g4particle->SetProperTime( (lv1-lv0).mag()/Gaudi::Units::c_light );
 
    CLHEP::Hep3Vector dist3D(endVtx.x()-prodVtx.x(), endVtx.y()-prodVtx.y(), endVtx.z()-prodVtx.z());
    double tau=SetProperTimeFromDetectorFrameDecayLength(*g4particle,dist3D.mag());
 
    if (msgLvl(MSG::VERBOSE)) {
      double pmag2=g4particle->GetTotalMomentum(); //magnitude of particle momentum
      pmag2*=pmag2;                                //magnitude of particle momentum squared
      double e2=g4particle->GetTotalEnergy();      //energy of particle
      e2*=e2;                                      //energy of particle squared
      double beta2=pmag2/e2;                       //beta^2=v^2/c^2 for particle
      double tau2=dist3D.mag2()*(1/beta2-1)/Gaudi::Units::c_light/Gaudi::Units::c_light;
      ATH_MSG_VERBOSE("lifetime tau(beta)="<<std::sqrt(tau2)<<" tau="<<tau);
    }
    if (m_quasiStableParticlesIncluded) {
      ATH_MSG_VERBOSE( "Detected primary particle with end vertex." );
      ATH_MSG_VERBOSE( "Will add the primary particle set on." );
      ATH_MSG_VERBOSE( "Primary Particle: " << genpart );
      ATH_MSG_VERBOSE( "Number of daughters : " << genpart->end_vertex()->particles_out().size()<<" at position "<<genpart->end_vertex() );
    }
    else {
      ATH_MSG_WARNING( "Detected primary particle with end vertex." );
      ATH_MSG_WARNING( "Will add the primary particle set on." );
      ATH_MSG_WARNING( "Primary Particle: " << genpart );
      ATH_MSG_WARNING( "Number of daughters: " << genpart->end_vertex()->particles_out().size()<<" at position "<<genpart->end_vertex() );
    }
    // Add all necessary daughter particles
    for ( auto daughter: genpart->end_vertex()->particles_out() ) {
      if (m_quasiStableParticlesIncluded) {
        ATH_MSG_VERBOSE ( "Attempting to add daughter particle: " << daughter );
      }
      else {
        ATH_MSG_WARNING ( "Attempting to add daughter particle: " << daughter );
      }
      G4PrimaryParticle *daughterG4Particle = this->getDaughterG4PrimaryParticle( daughter );
      if (!daughterG4Particle) {
        ATH_MSG_ERROR("Bailing out of loop over daughters of particle due to errors - will not return G4Particle.");
        return nullptr;
      }
      g4particle->SetDaughter( daughterG4Particle );
    }
  }
 
  return g4particle.release();
}
#else
G4PrimaryParticle* ISF::InputConverter::getDaughterG4PrimaryParticle(HepMC::GenParticle& genpart, bool makeLinkToTruth) const
{
  ATH_MSG_VERBOSE("Creating G4PrimaryParticle from GenParticle.");
 
  const G4ParticleDefinition *particleDefinition = this->getG4ParticleDefinition(genpart.pdg_id());
 
  if (particleDefinition==nullptr) {
    ATH_MSG_ERROR("ISF_to_G4Event particle conversion failed. ISF_Particle PDG code = " << genpart.pdg_id() <<
                  "\n This usually indicates a problem with the evgen step.\n" <<
                  "Please report this to the Generators group, mentioning the release and generator used for evgen and the PDG code above." );
    return nullptr;
  }
 
  // create new primaries and set them to the vertex
  //  G4double mass =  particleDefinition->GetPDGMass();
  auto &genpartMomentum = genpart.momentum();
  G4double px = genpartMomentum.x();
  G4double py = genpartMomentum.y();
  G4double pz = genpartMomentum.z();
 
  std::unique_ptr<G4PrimaryParticle> g4particle = std::make_unique<G4PrimaryParticle>(particleDefinition,px,py,pz);
 
  if (genpart.end_vertex()) {
    // Set the lifetime appropriately - this is slow but rigorous, and we
    //  don't want to end up with something like vertex time that we have
    //  to validate for every generator on earth...
    const auto& prodVtx = genpart.production_vertex()->position();
    const auto& endVtx = genpart.end_vertex()->position();
    //const G4LorentzVector lv0 ( prodVtx.x(), prodVtx.y(), prodVtx.z(), prodVtx.t() );
    //const G4LorentzVector lv1 ( endVtx.x(), endVtx.y(), endVtx.z(), endVtx.t() );
    //Old calculation, not taken because vertex information is not sufficiently precise
    //g4particle->SetProperTime( (lv1-lv0).mag()/Gaudi::Units::c_light );
 
    CLHEP::Hep3Vector dist3D(endVtx.x()-prodVtx.x(), endVtx.y()-prodVtx.y(), endVtx.z()-prodVtx.z());
    double tau=SetProperTimeFromDetectorFrameDecayLength(*g4particle,dist3D.mag());
 
    if (msgLvl(MSG::VERBOSE)) {
      double pmag2=g4particle->GetTotalMomentum(); //magnitude of particle momentum
      pmag2*=pmag2;                                //magnitude of particle momentum squared
      double e2=g4particle->GetTotalEnergy();      //energy of particle
      e2*=e2;                                      //energy of particle squared
      double beta2=pmag2/e2;                       //beta^2=v^2/c^2 for particle
      double tau2=dist3D.mag2()*(1/beta2-1)/Gaudi::Units::c_light/Gaudi::Units::c_light;
      ATH_MSG_VERBOSE("lifetime tau(beta)="<<std::sqrt(tau2)<<" tau="<<tau);
    }
    if (m_quasiStableParticlesIncluded) {
      ATH_MSG_VERBOSE( "Detected primary particle with end vertex." );
      ATH_MSG_VERBOSE( "Will add the primary particle set on." );
      ATH_MSG_VERBOSE( "Primary Particle: " << genpart );
      ATH_MSG_VERBOSE( "Number of daughters: " << genpart.end_vertex()->particles_out_size()<<" at position "<<genpart.end_vertex());
    }
    else {
      ATH_MSG_WARNING( "Detected primary particle with end vertex." );
      ATH_MSG_WARNING( "Will add the primary particle set on." );
      ATH_MSG_WARNING( "Primary Particle: " << genpart );
      ATH_MSG_WARNING( "Number of daughters: " << genpart.end_vertex()->particles_out_size()<<" at position "<<genpart.end_vertex() );
    }
    // Add all necessary daughter particles
    for ( auto daughterIter=genpart.end_vertex()->particles_out_const_begin();
          daughterIter!=genpart.end_vertex()->particles_out_const_end(); ++daughterIter ) {
      if (m_quasiStableParticlesIncluded) {
        ATH_MSG_VERBOSE ( "Attempting to add daughter particle: " << **daughterIter );
      }
      else {
        ATH_MSG_WARNING ( "Attempting to add daughter particle: " << **daughterIter );
      }
      G4PrimaryParticle *daughterG4Particle = this->getDaughterG4PrimaryParticle( **daughterIter, makeLinkToTruth );
      if (!daughterG4Particle) {
        ATH_MSG_ERROR("Bailing out of loop over daughters of particle due to errors - will not return G4Particle.");
        return nullptr;
      }
      g4particle->SetDaughter( daughterG4Particle );
    }
  }
 
  if (makeLinkToTruth) {
    // Set the user information for this primary to point to the HepMcParticleLink...
    std::unique_ptr<PrimaryParticleInformation> primaryPartInfo = std::make_unique<PrimaryParticleInformation>(&genpart);
    primaryPartInfo->SetRegenerationNr(0);
    g4particle->SetUserInformation(primaryPartInfo.release());
    ATH_MSG_VERBOSE("Making primary down the line with barcode " << primaryPartInfo->GetParticleUniqueID());
  }
 
  return g4particle.release();
}
#endif
 
//________________________________________________________________________
bool ISF::InputConverter::matchedGenParticles(const HepMC::ConstGenParticlePtr& p1,
                                              const HepMC::ConstGenParticlePtr& p2) const // TODO Helper method?
{
  return (HepMC::barcode(p1) == HepMC::barcode(p2))
    && (p1->status() == p2->status())
    && (p1->pdg_id() == p2->pdg_id())
    && ((p1->momentum().px()) == (p2->momentum().px()))
    && ((p1->momentum().py()) == (p2->momentum().py()))
    && ((p1->momentum().pz()) == (p2->momentum().pz()))
    && (float(p1->momentum().m()) == float(p2->momentum().m()));
}
 
//________________________________________________________________________
HepMC::GenParticlePtr ISF::InputConverter::findShadowParticle(const HepMC::ConstGenParticlePtr& genParticle, HepMC::GenEvent *shadowGenEvent) const // TODO Helper method?
{
  if (!shadowGenEvent) {
    ATH_MSG_FATAL ("Found status==2 GenParticle with no end vertex and shadow GenEvent is missing - something is wrong here!");
    abort();
  }
#ifdef HEPMC3
  // TODO in the future switch to using an Attribute which stores the shadow GenParticlePtr directly.
  const int shadowId = genParticle->attribute<HepMC3::IntAttribute>("ShadowParticleId")->value();
  for (auto& shadowParticle : shadowGenEvent->particles()) {
    if (shadowParticle->id() == shadowId && matchedGenParticles(genParticle, shadowParticle) ) { return shadowParticle; }
  }
  return std::make_shared<HepMC::GenParticle>();
#else
  for (HepMC::GenEvent::particle_iterator pitr=shadowGenEvent->particles_begin(); pitr != shadowGenEvent->particles_end(); ++pitr) {
    HepMC::GenParticlePtr shadowParticle = (*pitr);
    if (matchedGenParticles(genParticle, shadowParticle) ) { return shadowParticle; }
  }
  return nullptr;
#endif
 
}
 
#ifdef HEPMC3
//________________________________________________________________________
void ISF::InputConverter::processPredefinedDecays(const HepMC::ConstGenParticlePtr& genpart, ISF::ISFParticle& isp, G4PrimaryParticle* g4particle) const
{
  const auto& prodVtx = genpart->production_vertex()->position();
  const auto& endVtx = genpart->end_vertex()->position();
 
  CLHEP::Hep3Vector dist3D(endVtx.x()-prodVtx.x(), endVtx.y()-prodVtx.y(), endVtx.z()-prodVtx.z());
  double tau=SetProperTimeFromDetectorFrameDecayLength(*g4particle,dist3D.mag());
 
  if (msgLvl(MSG::VERBOSE)) {
    double pmag2=g4particle->GetTotalMomentum(); //magnitude of particle momentum
    pmag2*=pmag2;                                //magnitude of particle momentum squared
    double e2=g4particle->GetTotalEnergy();      //energy of particle
    e2*=e2;                                      //energy^2 of particle
    double beta2=pmag2/e2;                       //beta^2=v^2/c^2 for particle
    double mass2=g4particle->GetMass();          //mass of particle
    mass2*=mass2;                                //mass^2 of particle
 
    double tau2=dist3D.mag2()*(1/beta2-1)/Gaudi::Units::c_squared;
 
    const G4LorentzVector lv0( prodVtx.x(), prodVtx.y(), prodVtx.z(), prodVtx.t() );
    const G4LorentzVector lv1( endVtx.x(), endVtx.y(), endVtx.z(), endVtx.t() );
    //Old calculation, not taken because vertex information is not sufficiently precise
    //g4particle->SetProperTime( (lv1-lv0).mag()/Gaudi::Units::c_light );
    G4LorentzVector dist4D(lv1);
    dist4D-=lv0;
 
    double dist4Dgamma=std::numeric_limits<double>::infinity();
    if (dist4D.t()>0 && dist4D.mag2()>0) {
      dist4Dgamma=dist4D.gamma();
    } else {
      ATH_MSG_VERBOSE( "dist4D t="<<dist4D.t()<<" mag2="<<dist4D.mag2());
    }
 
    G4LorentzVector fourmom(g4particle->GetMomentum(),g4particle->GetTotalEnergy());
    double fourmomgamma=std::numeric_limits<double>::infinity();
    if (fourmom.t()>0 && fourmom.mag2()>0) {
      fourmomgamma=fourmom.gamma();
    } else {
      ATH_MSG_VERBOSE( "fourmom t="<<fourmom.t()<<" mag2="<<fourmom.mag2());
    }
 
    ATH_MSG_VERBOSE( "gammaVertex="<<dist4Dgamma<<" gammamom="<<fourmomgamma<<" gamma(beta)="<<1/std::sqrt(1-beta2)<<" lifetime tau(beta)="<<std::sqrt(tau2)<<" lifetime tau="<<tau);
  }
  if (m_quasiStableParticlesIncluded) {
    ATH_MSG_VERBOSE( "Detected primary particle with end vertex." );
    ATH_MSG_VERBOSE( "Will add the primary particle set on." );
    ATH_MSG_VERBOSE( "ISF Particle: " << isp );
    ATH_MSG_VERBOSE( "Primary Particle: " << genpart );
    ATH_MSG_VERBOSE( "Number of daughters: " << genpart->end_vertex()->particles_out().size() << " at position "<< genpart->end_vertex() );
  }
  else {
    ATH_MSG_WARNING( "Detected primary particle with end vertex. This should only be the case if" );
    ATH_MSG_WARNING( "you are running with quasi-stable particle simulation enabled.  This is not" );
    ATH_MSG_WARNING( "yet validated - you'd better know what you're doing.  Will add the primary" );
    ATH_MSG_WARNING( "particle set on." );
    ATH_MSG_WARNING( "ISF Particle: " << isp );
    ATH_MSG_WARNING( "Primary Particle: " << genpart );
    ATH_MSG_VERBOSE( "Number of daughters: " << genpart->end_vertex()->particles_out().size() );
  }
  // Add all necessary daughter particles
  for ( auto daughter: *(genpart->end_vertex())) {
    if (m_quasiStableParticlesIncluded) {
      ATH_MSG_VERBOSE ( "Attempting to add daughter particle" << daughter );
    }
    else {
      ATH_MSG_WARNING ( "Attempting to add daughter particle: " << daughter );
    }
    G4PrimaryParticle *daughterG4Particle = this->getDaughterG4PrimaryParticle( daughter );
    if (!daughterG4Particle) {
      ATH_MSG_FATAL("Bailing out of loop over daughters due to errors.");
    }
    g4particle->SetDaughter( daughterG4Particle );
  }
}
#endif
 
//________________________________________________________________________
void ISF::InputConverter::processPredefinedDecays(const HepMC::GenParticlePtr& genpart, ISF::ISFParticle& isp, G4PrimaryParticle* g4particle, bool makeLinkToTruth) const
{
  const auto& prodVtx = genpart->production_vertex()->position();
  const auto& endVtx = genpart->end_vertex()->position();
 
  CLHEP::Hep3Vector dist3D(endVtx.x()-prodVtx.x(), endVtx.y()-prodVtx.y(), endVtx.z()-prodVtx.z());
  double tau=SetProperTimeFromDetectorFrameDecayLength(*g4particle,dist3D.mag());
 
  if (msgLvl(MSG::VERBOSE)) {
    double pmag2=g4particle->GetTotalMomentum(); //magnitude of particle momentum
    pmag2*=pmag2;                                //magnitude of particle momentum squared
    double e2=g4particle->GetTotalEnergy();      //energy of particle
    e2*=e2;                                      //energy^2 of particle
    double beta2=pmag2/e2;                       //beta^2=v^2/c^2 for particle
    double mass2=g4particle->GetMass();          //mass of particle
    mass2*=mass2;                                //mass^2 of particle
 
    double tau2=dist3D.mag2()*(1/beta2-1)/Gaudi::Units::c_squared;
 
    const G4LorentzVector lv0( prodVtx.x(), prodVtx.y(), prodVtx.z(), prodVtx.t() );
    const G4LorentzVector lv1( endVtx.x(), endVtx.y(), endVtx.z(), endVtx.t() );
    //Old calculation, not taken because vertex information is not sufficiently precise
    //g4particle->SetProperTime( (lv1-lv0).mag()/Gaudi::Units::c_light );
    G4LorentzVector dist4D(lv1);
    dist4D-=lv0;
 
    double dist4Dgamma=std::numeric_limits<double>::infinity();
    if (dist4D.t()>0 && dist4D.mag2()>0) {
      dist4Dgamma=dist4D.gamma();
    } else {
      ATH_MSG_VERBOSE( "dist4D t="<<dist4D.t()<<" mag2="<<dist4D.mag2());
    }
 
    G4LorentzVector fourmom(g4particle->GetMomentum(),g4particle->GetTotalEnergy());
    double fourmomgamma=std::numeric_limits<double>::infinity();
    if (fourmom.t()>0 && fourmom.mag2()>0) {
      fourmomgamma=fourmom.gamma();
    } else {
      ATH_MSG_VERBOSE( "fourmom t="<<fourmom.t()<<" mag2="<<fourmom.mag2());
    }
 
    ATH_MSG_VERBOSE( "gammaVertex="<<dist4Dgamma<<" gammamom="<<fourmomgamma<<" gamma(beta)="<<1/std::sqrt(1-beta2)<<" lifetime tau(beta)="<<std::sqrt(tau2)<<" lifetime tau="<<tau);
  }
  if (m_quasiStableParticlesIncluded) {
    ATH_MSG_VERBOSE( "Detected primary particle with end vertex." );
    ATH_MSG_VERBOSE( "Will add the primary particle set on." );
    ATH_MSG_VERBOSE( "ISF Particle: " << isp );
    ATH_MSG_VERBOSE( "Primary Particle: " << genpart );
    ATH_MSG_VERBOSE( "Number of daughters: " << genpart->end_vertex()->particles_out_size() << " at position "<< genpart->end_vertex() );
  }
  else {
    ATH_MSG_WARNING( "Detected primary particle with end vertex. This should only be the case if" );
    ATH_MSG_WARNING( "you are running with quasi-stable particle simulation enabled.  This is not" );
    ATH_MSG_WARNING( "yet validated - you'd better know what you're doing.  Will add the primary" );
    ATH_MSG_WARNING( "particle set on." );
    ATH_MSG_WARNING( "ISF Particle: " << isp );
    ATH_MSG_WARNING( "Primary Particle: " << genpart );
    ATH_MSG_WARNING( "Number of daughters: " << genpart->end_vertex()->particles_out_size() );
  }
  // Add all necessary daughter particles
  for ( auto daughter: *(genpart->end_vertex())) {
    if (m_quasiStableParticlesIncluded) {
      ATH_MSG_VERBOSE ( "Attempting to add daughter particle: " << daughter );
    }
    else {
      ATH_MSG_WARNING ( "Attempting to add daughter particle: " << daughter );
    }
#ifdef HEPMC3
    G4PrimaryParticle *daughterG4Particle = this->getDaughterG4PrimaryParticle( daughter, makeLinkToTruth );
#else
    G4PrimaryParticle *daughterG4Particle = this->getDaughterG4PrimaryParticle( *daughter, makeLinkToTruth );
#endif
    if (!daughterG4Particle) {
      ATH_MSG_FATAL("Bailing out of loop over daughters due to errors.");
    }
    g4particle->SetDaughter( daughterG4Particle );
  }
}
 
G4PrimaryParticle* ISF::InputConverter::getG4PrimaryParticle(ISF::ISFParticle& isp, bool useHepMC, HepMC::GenEvent *shadowGenEvent) const
{
  ATH_MSG_VERBOSE("Creating G4PrimaryParticle from ISFParticle.");
 
  auto* truthBinding = isp.getTruthBinding();
  if (!truthBinding) {
    G4ExceptionDescription description;
    description << G4String("getG4PrimaryParticle: ") + "No ISF::TruthBinding associated with ISParticle (" << isp <<")";
    G4Exception("iGeant4::TransportTool", "NoISFTruthBinding", FatalException, description);
    return nullptr; //The G4Exception call above should abort the job, but Coverity does not seem to pick this up.
  }
  HepMC::GenParticlePtr currentGenPart = truthBinding->getCurrentGenParticle();
  HepMC::GenParticlePtr primaryGenpart = truthBinding->getPrimaryGenParticle();
 
  const G4ParticleDefinition *particleDefinition = this->getG4ParticleDefinition(isp.pdgCode());
 
  if (particleDefinition==nullptr) {
    ATH_MSG_ERROR("ISF_to_G4Event particle conversion failed. ISF_Particle PDG code = " << isp.pdgCode() <<
                  "\n This usually indicates a problem with the evgen step.\n" <<
                  "Please report this to the Generators group, mentioning the release and generator used for evgen and the PDG code above." );
    return nullptr;
  }
 
  // create new primaries and set them to the vertex
  //  G4double mass =  particleDefinition->GetPDGMass();
  G4double px(0.0);
  G4double py(0.0);
  G4double pz(0.0);
  if (useHepMC && currentGenPart) {
    auto &currentGenPartMomentum = currentGenPart->momentum();
    px = currentGenPartMomentum.x();
    py = currentGenPartMomentum.y();
    pz = currentGenPartMomentum.z();
  }
  else {
    auto &ispMomentum = isp.momentum();
    px = ispMomentum.x();
    py = ispMomentum.y();
    pz = ispMomentum.z();
  }
 
  std::unique_ptr<G4PrimaryParticle> g4particle = std::make_unique<G4PrimaryParticle>(particleDefinition,px,py,pz);
  // UserInformation
  std::unique_ptr<PrimaryParticleInformation> primaryPartInfo = std::make_unique<PrimaryParticleInformation>(primaryGenpart,&isp);
 
  const int regenerationNr = HepMC::StatusBased::generations(&isp);
  if (HepMC::BarcodeBased::generations(&isp) != regenerationNr) {
    ATH_MSG_WARNING ("StatusBased::generations() = " << regenerationNr << ", BarcodeBased::generations()  = " << HepMC::BarcodeBased::generations(&isp) << ", isp: " << isp);
  }
  primaryPartInfo->SetRegenerationNr(regenerationNr);
 
  if ( currentGenPart ) {
    if (currentGenPart->end_vertex()) {
      // Old approach particle had an end vertex - predefined decays taken from the main GenEvent
      // No longer supported
      ATH_MSG_ERROR ( "getG4PrimaryParticle(): GenParticle has a valid end GenVertexPtr!" );
      ATH_MSG_ERROR ( "getG4PrimaryParticle(): currentGenPart: " << currentGenPart << ", barcode: " << HepMC::barcode(currentGenPart) );
      ATH_MSG_ERROR ( "getG4PrimaryParticle(): currentGenPart->end_vertex(): " << currentGenPart->end_vertex() << ", barcode: " << HepMC::barcode(currentGenPart->end_vertex()) );
      ATH_MSG_FATAL ( "getG4PrimaryParticle(): Passing GenParticles with a valid end GenVertexPtr as input is no longer supported." );
      abort();
    }
    else if (MC::isDecayed(currentGenPart) // Some assumptions about main GenEvent here
             && !currentGenPart->end_vertex()) {
      // New approach - predefined decays taken from shadow GenEvent
      // Find the matching particle in the shadowGenEvent
#ifdef HEPMC3
      auto A_part = currentGenPart->attribute<HepMC::ShadowParticle>("ShadowParticle");
      HepMC::ConstGenParticlePtr shadowPart = (A_part) ? A_part->value() : findShadowParticle(currentGenPart, shadowGenEvent);
#else
      HepMC::GenParticlePtr shadowPart = findShadowParticle(currentGenPart, shadowGenEvent);
#endif
      if (!shadowPart) {
        ATH_MSG_FATAL ("Found a GenParticle with no matching GenParticle in the shadowGenEvent - something is wrong here!");
        abort();
      }
      if (!shadowPart->end_vertex()) {
        ATH_MSG_FATAL ("Found status==2 shadow GenParticle with no end vertex - something is wrong here!");
        abort();
      }
#ifdef HEPMC3
      processPredefinedDecays(shadowPart, isp, g4particle.get());
#else
      processPredefinedDecays(shadowPart, isp, g4particle.get(), false); // false to avoid truth-links to the shadow GenEvent
#endif
    }
 
    double px,py,pz;
    const double pmass = g4particle->GetMass();
    CLHEP::Hep3Vector gpv = g4particle->GetMomentum();
    double g4px=g4particle->GetMomentum().x();
    double g4py=g4particle->GetMomentum().y();
    double g4pz=g4particle->GetMomentum().z();
    if (useHepMC) {
      //Code adapted from TruthHepMCEventConverter::TransformHepMCParticle
      px=g4px;
      py=g4py;
      pz=g4pz;
    } else {
      //Take mass from g4particle, put keep momentum as in currentGenPart
      px=currentGenPart->momentum().px();
      py=currentGenPart->momentum().py();
      pz=currentGenPart->momentum().pz();
      //Now a dirty hack to keep backward compatibility in the truth:
      //When running AtlasG4 or FullG4 between 21.0.41 and 21.0.111, the currentGenPart 3-momentum and mass was reset to the values from the g4particle
      //together with the mass of the g4particle after the 1st initialization of the g4particle from the genevent. This is done for a consistent mass
      //value in the truth record compared to the used g4 mass. Since g4particles don't store the 3-momentum directly, but rather a
      //unit direction vector, the mass and the kinetic energy, this reduces the numeric accuracy.
      //For backward compatibility, if all 3-momentum components agree to the g4particle momentum within 1 keV, we keep
      //this old method. This comparison is needed, since in ISF this code could be rerun after the ID or CALO simulation, where
      //real energy was lost in previous detectors and hence currentGenPart should NOT be changed to some g4particle values!
      //TODO: find a way to implement this in a backward compatible way in ISF::InputConverter::convertParticle(HepMC::GenParticlePtr genPartPtr)
      if (std::abs(px-g4px)<CLHEP::keV && std::abs(py-g4py)<CLHEP::keV && std::abs(pz-g4pz)<CLHEP::keV) {
        px=g4px;
        py=g4py;
        pz=g4pz;
      }
    }
    const double mag2=px*px + py*py + pz*pz;
    const double pe = std::sqrt(mag2 + pmass*pmass);  // this does only change for boosts, etc.
 
    double originalEnergy=currentGenPart->momentum().e();
    if (originalEnergy>0.01) { //only test for >1 MeV in momentum
      if ((originalEnergy-pe)/originalEnergy>0.01) {
        double genpx=currentGenPart->momentum().px();
        double genpy=currentGenPart->momentum().py();
        double genpz=currentGenPart->momentum().pz();
        double genp=sqrt(genpx*genpx + genpy*genpy + genpz*genpz);
        ATH_MSG_WARNING("Truth change in energy for: " << currentGenPart<<" Morg="<<currentGenPart->momentum().m()<<" Mmod="<<pmass<<" Eorg="<<originalEnergy<<" Emod="<<pe<<" porg="<<genp<<" pmod="<<gpv.mag());
      }
    }
 
#ifdef HEPMC3
    auto& currentGenPart_nc = currentGenPart;
#else
    auto* currentGenPart_nc = currentGenPart;
#endif
    currentGenPart_nc->set_momentum(HepMC::FourVector(px,py,pz,pe));
  } // Truth was detected
 
  ATH_MSG_VERBOSE("PrimaryParticleInformation:");
  ATH_MSG_VERBOSE("     GetParticleUniqueID = " << primaryPartInfo->GetParticleUniqueID());
  ATH_MSG_VERBOSE("     GetRegenerationNr = " << primaryPartInfo->GetRegenerationNr());
  ATH_MSG_VERBOSE("     GetHepMCParticle = " << primaryPartInfo->GetHepMCParticle());
  ATH_MSG_VERBOSE("     GetISFParticle = " << primaryPartInfo->GetISFParticle());
  g4particle->SetUserInformation(primaryPartInfo.release());
 
  return g4particle.release();
}
 
//________________________________________________________________________
void ISF::InputConverter::addG4PrimaryVertex(G4Event* g4evt, ISF::ISFParticle& isp, bool useHepMC, HepMC::GenEvent *shadowGenEvent) const
{
  /*
    see conversion from PrimaryParticleInformation to TrackInformation in
    http://acode-browser.usatlas.bnl.gov/lxr/source/atlas/Simulation/G4Atlas/G4AtlasAlg/src/AthenaStackingAction.cxx#0044
 
    need to check with
    http://acode-browser.usatlas.bnl.gov/lxr/source/atlas/Simulation/G4Atlas/G4AtlasAlg/src/TruthHepMCEventConverter.cxx#0151
 
    that we don't miss something
  */
 
  G4PrimaryParticle *g4particle = this->getG4PrimaryParticle( isp, useHepMC, shadowGenEvent );
  if (!g4particle) {
    ATH_MSG_ERROR("Failed to create G4PrimaryParticle for ISParticle (" << isp <<")");
    return;
  }// Already printed a warning
 
  // create a new vertex
  G4PrimaryVertex *g4vertex = new G4PrimaryVertex(isp.position().x(),
                                                  isp.position().y(),
                                                  isp.position().z(),
                                                  isp.timeStamp());
  g4vertex->SetPrimary( g4particle );
  ATH_MSG_VERBOSE("Print G4PrimaryVertex: ");
  if (msgLevel(MSG::VERBOSE)) { g4vertex->Print(); }
  g4evt->AddPrimaryVertex( g4vertex );
  return;
}
 
//________________________________________________________________________
bool ISF::InputConverter::isInsideG4WorldVolume(const ISF::ISFParticle& isp, const G4VSolid* worldSolid) const
{
 
  const Amg::Vector3D &pos = isp.position();
  const G4ThreeVector g4Pos( pos.x(), pos.y(), pos.z() );
  EInside insideStatus = worldSolid->Inside( g4Pos );
 
  bool insideWorld = insideStatus != kOutside;
  return insideWorld;
}