LArFastShower.cxx

Go to the documentation of this file.

/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
 
#include "LArFastShower.h"
 
#include "GaudiKernel/Bootstrap.h"
#include "GaudiKernel/ISvcLocator.h"
#include "LArG4Code/EnergySpot.h"
 
#include "AtlasHepMC/GenEvent.h"
#include "AtlasHepMC/GenParticle.h"
#include "AtlasHepMC/GenVertex.h"
#include "AtlasHepMC/IO_GenEvent.h"
#include "CLHEP/Random/RandFlat.h"
 
#include <stdexcept>
 
#include "G4Electron.hh"
#include "G4Gamma.hh"
#include "G4Positron.hh"
#include "G4Neutron.hh"
#include "G4PionPlus.hh"
#include "G4PionMinus.hh"
#include "G4VSensitiveDetector.hh"
#include "G4EventManager.hh"
#include "LArG4ShowerLibSvc/ILArG4ShowerLibSvc.h"
#include "IFastSimDedicatedSD.h"
 
#include "GaudiKernel/ConcurrencyFlags.h"
 
#undef _TRACE_FSM_
#undef _TRACE_DOIT_
#undef _TRACE_POSITION_
#undef _INFO_FSM_
 
 
LArFastShower::LArFastShower(const std::string& name, G4Region* region, const FastShowerConfigStruct& config,
                             IFastSimDedicatedSD* fastSimDedicatedSD):
  G4VFastSimulationModel(name, region),
  m_configuration(config),
  m_fastSimDedicatedSD(fastSimDedicatedSD),
  m_showerLibSvc(nullptr),
  m_generate_starting_points(false),
  m_starting_points_file(),
  m_eventNum(0)
{
  /* Starting points, i.e. vertex coordinates, are needed to create 
   * the Frozen Shower library, so they are saved in a hepmc file. 
   * Frozen showers are then simulated from these starting points 
   * in a separate job. To speed up the simulation, 
   * showers will be read from the library instead of being simulated.*/
  m_generate_starting_points = (!m_configuration.m_generated_starting_points_file.empty());
  if (m_generate_starting_points) {
    std::string hepmcFileName = m_configuration.m_generated_starting_points_file;
    
    // In multi-thread run, multiple hepmc files are created.
    // To distinguish between them we add thread_id in their name. 
    if (Gaudi::Concurrency::ConcurrencyFlags::numThreads() > 1)
      {
    auto threadId = std::this_thread::get_id();
    std::stringstream ss;
    ss << threadId;
    hepmcFileName += "."+ss.str();
      }
    m_starting_points_file  = std::make_shared<HepMC3::WriterAscii>(hepmcFileName);
  }
 
  enum DETECTOR { EMB=100000, EMEC=200000, FCAL1=300000, FCAL2=400000,
                  FCAL3=500000, HECLOC=600000, HEC=700000 };
 
  m_detmap["EMB"]=EMB;
  m_detmap["EMEC"]=EMEC;
  m_detmap["FCAL1"]=FCAL1;
  m_detmap["FCAL2"]=FCAL2;
  m_detmap["FCAL3"]=FCAL3;
  m_detmap["HECLOC"]=HECLOC;
  m_detmap["HEC"]=HEC;
}
 
IFastSimDedicatedSD* LArFastShower::fastShowerSD()
{
  if ( !m_fastSimDedicatedSD ) {
    throw std::runtime_error("LArFastShower: no pointer to IFastSimDedicatedSD!");
  }
  return m_fastSimDedicatedSD;
}
 
 
ILArG4ShowerLibSvc* LArFastShower::showerLibSvc()
{
  if ( !m_showerLibSvc ) {
    SmartIF<ILArG4ShowerLibSvc> smartShowerLibSvc{Gaudi::svcLocator()->service(m_configuration.m_showerLibSvcName)};
    if ( smartShowerLibSvc ) { m_showerLibSvc = smartShowerLibSvc.get(); }
    if ( !m_showerLibSvc ) {
      throw std::runtime_error("LArFastShower: cannot retrieve LArG4ShowerLibSvc");
    }
  }
  return m_showerLibSvc;
}
 
 
G4bool LArFastShower::IsApplicable(const G4ParticleDefinition& particleType)
{
#ifdef _TRACE_FSM_
  G4cout << "LArFastShower::IsApplicable" << G4endl;
#endif
 
  /*
   * if ( flag to parameterize is set )
   * && ( (we want to record SPs) || (ShowerLibSvc has a library for this particle) )
   */
  if (m_applicableMap.find(particleType.GetPDGEncoding()) != m_applicableMap.end()) {
    return m_applicableMap.find(particleType.GetPDGEncoding())->second;
  }
  bool rez = false;
  if ( flagToShowerLib(particleType) &&
       ( m_generate_starting_points ||
         showerLibSvc()->checkLibrary( particleType.GetPDGEncoding(),
                                       m_configuration.m_detector_tag ) ))
    rez = true;
  m_applicableMap[particleType.GetPDGEncoding()] = rez;
  return rez;
}
 
G4bool LArFastShower::ModelTrigger(const G4FastTrack& fastTrack)
{
  /* ==========================================================================
     Determine if the particle is to be returned to full Geant4 simulation.
     In the event where the particle is EITHER killed and parameterised OR
     simply killed, this must be done in the appropriate LArFastShower DoIt method.
     This method Checks: 1) Geometry; 2) Energy; 3) (for e+/e-) Containment
     ========================================================================== */
 
#ifdef _TRACE_FSM_
  G4cout << "LArFastShower::commonTrigger" << G4endl;
#endif
 
  // We are in a parameterized volume
 
  // Check if the particle is within energy bounds
  G4double particleEnergy = fastTrack.GetPrimaryTrack()->GetKineticEnergy();
  const G4ParticleDefinition& particleType = *(fastTrack.GetPrimaryTrack()->GetDefinition());
 
  if ( flagToShowerLib(particleType) == true &&
       particleEnergy > minEneToShowerLib(particleType) &&
       particleEnergy < maxEneToShowerLib(particleType) ) {
 
#ifdef _TRACE_FSM_
    G4cout << "Particle has energy (" << particleEnergy << ") for shower lib and shower lib is on! Accept particle!" << G4endl;
#endif
  }  else {
 
#ifdef _TRACE_FSM_
    G4cout << "Particle has energy (" << particleEnergy << ") outside killing, shower lib and parametrisation "
           << "or some features are switched off ... returning it to Geant  " << G4endl;
#endif
 
    return false;
  }
 
  if (ForcedAccept(fastTrack)) return true;
  if (ForcedDeny(fastTrack)) return false;
 
  if (CheckContainment(fastTrack)==false) {
#ifdef _TRACE_FSM_
    G4cout << "LArFastShower::ModelTrigger() particle failed CheckContainment()... will not be parameterised: " << G4endl;
#endif
    return false;
  }
 
#ifdef _TRACE_FSM_
  G4cout << "LArFastShower::ModelTrigger() direction: " << fastTrack.GetPrimaryTrackLocalDirection() << G4endl;
  G4cout << "LArFastShower::ModelTrigger() mom dir:   " << fastTrack.GetPrimaryTrack()->GetMomentumDirection() << G4endl;
#endif
 
  return true;
}
 
 
void LArFastShower::DoIt(const G4FastTrack& fastTrack, G4FastStep& fastStep)
{
#ifdef _TRACE_FSM_
  G4cout << "LArFastShower::Doit()" << G4endl;
#endif
 
  if ( m_generate_starting_points ) {
    if (CLHEP::RandFlat::shoot(G4Random::getTheEngine()) <= m_configuration.m_generated_starting_points_ratio) {
      std::unique_ptr<const HepMC::GenEvent> ge = GetGenEvent(fastTrack);
      generateFSStartingPoint(ge);
    }
    KillParticle( fastTrack, fastStep );
    return;
  }
  this->UseShowerLib( fastTrack, fastStep );
 
#ifdef _TRACE_FSM_
  G4cout << "LArFastShower::Doit() done" << G4endl;
#endif
 
}
 
#ifdef _TRACE_DOIT_
void LArFastShower::KillParticle(const G4FastTrack& fastTrack, G4FastStep& fastStep)
#else
void LArFastShower::KillParticle(const G4FastTrack&, G4FastStep& fastStep)
#endif
{
 
#ifdef _TRACE_DOIT_
  G4cout << "Low energy particle is being killed: " << fastTrack.GetPrimaryTrack()->GetKineticEnergy() << G4endl;
#endif
 
  // Kill the particle
  fastStep.KillPrimaryTrack();
  fastStep.ProposePrimaryTrackPathLength(0.0);
 
  return;
}
 
void LArFastShower::UseShowerLib(const G4FastTrack& fastTrack, G4FastStep& fastStep)
{
  try {
#ifdef _TRACE_DOIT_
    G4cout << "LArFastShower::UseShowerLib()" << G4endl;
#endif
 
    // kill the electron to be parametrised
    KillParticle(fastTrack, fastStep);
 
    // -----------------------------
    // Get Shower from ShowerLibSvc
    // -----------------------------
    const std::vector<EnergySpot> shower =
      showerLibSvc()->getShower(fastTrack, m_configuration.m_detector_tag);
 
#ifdef _TRACE_DOIT_
    G4cout << "Got shower (" << shower.size() << ") from shower lib" << G4endl;
#endif
    const double weight = (m_configuration.m_applyRRWeights) ? fastTrack.GetPrimaryTrack()->GetWeight() : 1.0;
    // loop over hits in shower
    for (const auto& a_spot : shower) {
 
#ifdef _TRACE_DOIT_
      G4cout << "Make Spot: " << a_spot.GetPosition().x() << " "
             << a_spot.GetPosition().y() << " " << a_spot.GetPosition().z()
             << " " << a_spot.GetEnergy() << " " << a_spot.GetTime() << G4endl;
#endif
      fastShowerSD()->ProcessSpot(a_spot, weight);
 
#ifdef _TRACE_DOIT_
      G4cout << "Made Spot" << G4endl;
#endif
 
    }
 
#ifdef _TRACE_FSM_
    G4cout << "LArFastShower::UseShowerLib() Done" << G4endl;
#endif
 
    return;
  }
 
  // FIXME: Catching all exceptions and suppressing them? That's awful!!
  catch (const std::exception & e) {
    G4cout << "FastShower::UseShowerLib ERROR Handling an exception in LArFastShower::" << e.what() << G4endl;
    return;
  }
 
}
 
G4bool LArFastShower::CheckContainment(const G4FastTrack &fastTrack)
{
 
  G4ThreeVector showerDirection = fastTrack.GetPrimaryTrack()->GetMomentumDirection();
  G4ThreeVector initialShowerPosition = fastTrack.GetPrimaryTrack()->GetPosition();
  G4ThreeVector orthoShower = showerDirection.orthogonal();
  G4ThreeVector crossShower = showerDirection.cross(orthoShower);
 
#ifdef _TRACE_FSM_
  G4cout << "LArFastShower::CheckContainment() orthoShower: " << orthoShower << G4endl;
  G4cout << "LArFastShower::CheckContainment() crossShower: " << crossShower << G4endl;
#endif
 
  //Build 5 points at the shower max. edges and far end
  //this picks the points where 99% of the particle energy was already deposited
  /* Short history of containment check:
   * First, it was magic numbers from ShowerParams class
   G4double Zmx    = myParameterisation()->GetAveZmx();
   G4double  R     = myParameterisation()->GetAveR90(); // Easy - just multiply
   G4double  Z     = myParameterisation()->GetAveZ90(); // More convoluted
   * Then, after ShowerParams class was sent to code heaven, the magic numbers were saved from it
   * and stored right here:
   G4double Zmx = 22*mm;
   G4double R   = 1.5*4*cm;
   G4double Z   = 22*2.5*mm;
   * Now, we take it directly from the library
   */
  G4double Z = showerLibSvc()->getContainmentZ(fastTrack,m_configuration.m_detector_tag);
  G4double R = showerLibSvc()->getContainmentR(fastTrack,m_configuration.m_detector_tag);
 
  if (Z == 0.0 && R == 0.0) {
    // no containment check
    return true;
  }
 
  // Here is OUR magic number. Looking on the hit distribution plot,
  // it seems that that way most of hits will be inside
  G4double Zmx = Z / 3;
 
  G4int cosPhi[4] = {1,0,-1,0};
  G4int sinPhi[4] = {0,1,0,-1};
 
#ifdef _TRACE_FSM_
  G4cout << "LArFastShower::CheckContainment() R =          " << R   << G4endl;
  G4cout << "LArFastShower::CheckContainment() Z =          " << Z   << G4endl;
#endif
 
  G4ThreeVector position;
 
  G4VSolid* caloSolid = fastTrack.GetEnvelopeSolid();
  const G4AffineTransform* affineTransformation = fastTrack.GetAffineTransformation();
 
  //Startpoint
  position = initialShowerPosition;
  affineTransformation->ApplyPointTransform(position);
  if(caloSolid->Inside(position) == kOutside)
    return false;
 
  //Longitudinal Endpoint
  position = initialShowerPosition + Z*showerDirection;
  affineTransformation->ApplyPointTransform(position);
  if(caloSolid->Inside(position) == kOutside)
    return false;
 
  //Lateral Spread
  for(int i=0; i<4 ;i++)
    {
      position = initialShowerPosition + Zmx*showerDirection +
                 R*cosPhi[i]*orthoShower + R*sinPhi[i]*crossShower;
      affineTransformation->ApplyPointTransform(position);
      if(caloSolid->Inside(position) == kOutside)
        return false;
    }
 
#ifdef _TRACE_FSM_
  G4cout << "LArFastShower::CheckContainment()  Shower is contained " << G4endl;
#endif
 
  return true;
 
}
 
std::unique_ptr<const HepMC::GenEvent> LArFastShower::GetGenEvent(const G4FastTrack &fastTrack)
{
  const G4ThreeVector showerPos = fastTrack.GetPrimaryTrack()->GetPosition();
  const G4ThreeVector showerMom = fastTrack.GetPrimaryTrack()->GetMomentum();
  const G4double energy = fastTrack.GetPrimaryTrack()->GetKineticEnergy();
 
  G4int pdgcode = fastTrack.GetPrimaryTrack()->GetDefinition()->GetPDGEncoding();
  if (pdgcode < 0) pdgcode = -pdgcode; // hack for positrons. let it be electrons.
 
  HepMC3::Units::MomentumUnit momentumUnit = HepMC3::Units::MEV;
  HepMC3::Units::LengthUnit lengthUnit = HepMC3::Units::MM;
  // new event. Signal processing = 0, event number "next"
  std::unique_ptr<HepMC::GenEvent> ge = std::make_unique<HepMC::GenEvent>(momentumUnit,lengthUnit);
 
  ge->set_event_number(++m_eventNum);
 
  // starting point from which the shower develops, time = 0. 
  HepMC::GenVertexPtr gv = HepMC::newGenVertexPtr(
      HepMC::FourVector(showerPos.x(), showerPos.y(), showerPos.z(), 0) );
  ge->add_vertex(gv);
 
  // input particle (status=4) is always required by HepMC.
  // make it a dummy geantino with 4-mom=0. pdg_id=999.
  HepMC::GenParticlePtr gpi = HepMC::newGenParticlePtr(
      HepMC::FourVector(0.,0.,0.,0.),
      999, 4 );
  gv->add_particle_in(std::move(gpi));
 
  // output particle (status=1) is the FourVector of the shower.
  HepMC::GenParticlePtr gpo = HepMC::newGenParticlePtr(
      HepMC::FourVector(showerMom.x(), showerMom.y(), showerMom.z(), energy),
      pdgcode, 1 );
  gv->add_particle_out(std::move(gpo));
 
  // return auto_pointer. will be deleted automatically
  return ge;
}
 
// Helper methods
bool   LArFastShower::flagToShowerLib( const G4ParticleDefinition& particleType )   const
{
  if ( &particleType == G4Electron::ElectronDefinition() ||
       &particleType == G4Positron::PositronDefinition() ) {
    return m_configuration.m_e_FlagShowerLib;
  } else if ( &particleType == G4Gamma::GammaDefinition() ) {
    return m_configuration.m_g_FlagShowerLib;
  } else if ( &particleType == G4Neutron::NeutronDefinition() ) {
    return m_configuration.m_Neut_FlagShowerLib;
  } else if ( &particleType == G4PionPlus::PionPlusDefinition() ||
              &particleType == G4PionMinus::PionMinusDefinition() ) {
    return m_configuration.m_Pion_FlagShowerLib;
  }
  return false;
}
double LArFastShower::minEneToShowerLib( const G4ParticleDefinition& particleType ) const
{
  if ( &particleType == G4Electron::ElectronDefinition() ||
       &particleType == G4Positron::PositronDefinition() ) {
    return m_configuration.m_e_MinEneShowerLib;
  } else if ( &particleType == G4Gamma::GammaDefinition() ) {
    return m_configuration.m_g_MinEneShowerLib;
  } else if ( &particleType == G4Neutron::NeutronDefinition() ) {
    return m_configuration.m_Neut_MinEneShowerLib;
  } else if ( &particleType == G4PionPlus::PionPlusDefinition() ||
              &particleType == G4PionMinus::PionMinusDefinition() ) {
    return m_configuration.m_Pion_MinEneShowerLib;
  }
  return 0.0;
}
 
double LArFastShower::maxEneToShowerLib( const G4ParticleDefinition& particleType ) const
{
  if ( &particleType == G4Electron::ElectronDefinition() ||
       &particleType == G4Positron::PositronDefinition() ) {
    return m_configuration.m_e_MaxEneShowerLib;
  } else if ( &particleType == G4Gamma::GammaDefinition() ) {
    return m_configuration.m_g_MaxEneShowerLib;
  } else if ( &particleType == G4Neutron::NeutronDefinition() ) {
    return m_configuration.m_Neut_MaxEneShowerLib;
  } else if ( &particleType == G4PionPlus::PionPlusDefinition() ||
              &particleType == G4PionMinus::PionMinusDefinition() ) {
    return m_configuration.m_Pion_MaxEneShowerLib;
  }
  return 0.0;
}
bool LArFastShower::generateFSStartingPoint( std::unique_ptr<const HepMC::GenEvent> &ge ) const
{
  if (!m_generate_starting_points)
    return false;
  m_starting_points_file->write_event(*ge);
  return true;
}
G4bool LArFastShower::ForcedAccept(const G4FastTrack & fastTrack)
{
  G4ThreeVector initialShowerPosition = fastTrack.GetPrimaryTrack()->GetPosition();
 
  // if ( !m_configuration.m_containHigh &&
  //     ( initialShowerPosition.eta()>=m_configuration.m_absHighEta ||
  //       initialShowerPosition.eta()<=-m_configuration.m_absHighEta ) ) return true;
 
  if ( !m_configuration.m_containHigh &&
      ( initialShowerPosition.eta()>m_configuration.m_absHighEta ||
        initialShowerPosition.eta()<-m_configuration.m_absHighEta ) ) return true;
 
  if ( !m_configuration.m_containCrack &&
      ( ( initialShowerPosition.eta()>m_configuration.m_absCrackEta1 &&
          initialShowerPosition.eta()<m_configuration.m_absCrackEta2 ) ||
        ( initialShowerPosition.eta()<-m_configuration.m_absCrackEta1 &&
          initialShowerPosition.eta()>-m_configuration.m_absCrackEta2 ) ) ) return true;
 
  if ( !m_configuration.m_containLow &&
      ( initialShowerPosition.eta()<m_configuration.m_absLowEta ||
        initialShowerPosition.eta()>-m_configuration.m_absLowEta ) ) return true;
  return false;
}
 
G4bool LArFastShower::ForcedDeny  (const G4FastTrack &)
{
  return false;
}