EvtInclusiveDecay.cxx

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//*****************************************************************************
//
// Generators/EvtGen_i/EvtInclusiveDecay.h
//
// EvtInclusiveDecay is a TopAlg that takes HepMC events from StoreGate and
// generates particle decays using EvtGen. Depending on job options either all or
// only a subset of the particles which have decays defined in the EvtGen
// decay files will be handed to EvtGen. Both undecayed particles and particles
// with an existing decay tree can be handled (in the latter case,
// EvtInclusiveDecay will remove the existing decay tree).
//
// Written in February 2006 by Juerg Beringer, based in part on the existing
// EvtDecay module.
//
//*****************************************************************************
 
#include "EvtGen_i/EvtInclusiveDecay.h"
 
#include "EvtGenBase/EvtAbsRadCorr.hh"
#include "EvtGenBase/EvtDecayBase.hh"
#include "EvtGen_i/EvtGenExternal/EvtExternalGenList.hh"
 
#include "EvtGenBase/EvtVector4R.hh"
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtParticleFactory.hh"
#include "EvtGen/EvtGen.hh"
#include "EvtGenBase/EvtRandomEngine.hh"
#include "EvtGenBase/EvtDecayTable.hh"
 
#include "PathResolver/PathResolver.h"
 
#include "AtlasHepMC/GenEvent.h"
#include "AtlasHepMC/GenVertex.h"
#include "AtlasHepMC/GenParticle.h"
#include "TruthUtils/MagicNumbers.h"
#include "TruthUtils/HepMCHelpers.h"
 
#include "GaudiKernel/MsgStream.h"
#include "GaudiKernel/ISvcLocator.h"
#include "GaudiKernel/DataSvc.h"
#include "StoreGate/StoreGateSvc.h"
#include "GeneratorObjects/McEventCollection.h"
 
#include "AthenaKernel/RNGWrapper.h"
#include "CLHEP/Random/RandFlat.h"
#include "CLHEP/Vector/LorentzVector.h"
#include "CxxUtils/checker_macros.h"
 
#include <stdlib.h>
#include <sstream>
#include <map>
 
 
EvtInclusiveDecay::EvtInclusiveDecay(const std::string& name, ISvcLocator* pSvcLocator):
  GenBase( name, pSvcLocator ),
  m_nRepeatedDecays(0) {
 
  // Basic EvtGen configuration: decay and particle definition files, random number stream
  declareProperty("pdtFile", m_pdtFile = "inclusive.pdt");
  declareProperty("decayFile", m_decayFile = "2014inclusive.dec");
  declareProperty("userDecayFile", m_userDecayFile = "");
  declareProperty("randomStreamName", m_randomStreamName = "EVTGEN");
  declareProperty("inputKeyName", m_inputKeyName = "GEN_EVENT");
  declareProperty("outputKeyName",m_outputKeyName = "GEN_EVENT_EVTGEN");
  declareProperty("readExisting",m_readExisting=false);
 
  // Selection of particles to be decayed
  declareProperty("prohibitFinalStateDecay", m_prohibitFinalStateDecay=false);
  declareProperty("prohibitReDecay", m_prohibitReDecay=false);
  declareProperty("prohibitUnDecay", m_prohibitUnDecay=true);
  declareProperty("prohibitRemoveSelfDecay", m_prohibitRemoveSelfDecay=false);
  declareProperty("blackList",m_blackList);
  declareProperty("allowAllKnownDecays", m_allowAllKnownDecays=true);
  declareProperty("allowDefaultBDecays", m_allowDefaultBDecays=true);
  declareProperty("whiteList",m_whiteList);
 
  // Level of output
  declareProperty("printHepMCBeforeEvtGen", m_printHepMCBeforeEvtGen=false);
  declareProperty("printHepMCAfterEvtGen", m_printHepMCAfterEvtGen=false);
  declareProperty("printHepMCHighlighted", m_printHepMCHighlighted=true);
  declareProperty("printHepMCHighLightTopLevelDecays", m_printHepMCHighLightTopLevelDecays=true);
 
  // Optional checks
  declareProperty("checkDecayTree", m_checkDecayTree=false);
  declareProperty("checkDecayChannels", m_checkDecayChannels=false);
 
  // Repeated decays
  declareProperty("maxNRepeatedDecays", m_maxNRepeatedDecays=1);
 
  // User selection
  declareProperty("applyUserSelection", m_applyUserSelection=false);
  declareProperty("userSelRequireOppositeSignedMu", m_userSelRequireOppositeSignedMu=true);
  declareProperty("userSelMu1MinPt", m_userSelMu1MinPt=0.);
  declareProperty("userSelMu2MinPt", m_userSelMu2MinPt=0.);
  declareProperty("userSelMu1MaxEta", m_userSelMu1MaxEta=102.5);
  declareProperty("userSelMu2MaxEta", m_userSelMu2MaxEta=102.5);
  declareProperty("userSelMinDimuMass", m_userSelMinDimuMass=0.);
  declareProperty("userSelMaxDimuMass", m_userSelMaxDimuMass=-1.); // set to negative to not apply cut
  declareProperty("isfHerwig", m_isfHerwig=false);
  declareProperty("setVMtransversePol", m_setVMtransversePol=false);
 
  // We have decided to blacklist Tau decays because we are not sure whether the polarization
  // would be properly passed to EvtGen
  m_blackList.push_back(15);
}
 
 
 
EvtInclusiveDecay::~EvtInclusiveDecay() {
  delete m_myEvtGen;
  delete m_evtAtRndmGen;
}
 
 
 
StatusCode EvtInclusiveDecay::initialize() {
 
  ATH_CHECK( GenBase::initialize() );
  // Get the random number service
  CHECK(m_rndmSvc.retrieve());
 
  msg(MSG::INFO) << "EvtInclusiveDecay initialize" << endmsg;
  msg(MSG::INFO) << "Particle properties definition file = " << m_pdtFile << endmsg;
  msg(MSG::INFO) << "Main decay file                     = " << m_decayFile << endmsg;
  msg(MSG::INFO) << "User decay file                     = " << m_userDecayFile << endmsg;
  msg(MSG::INFO) << "Max number of repeated decays       = " << m_maxNRepeatedDecays << endmsg;
  msg(MSG::INFO) << "EvtInclusiveDecay selection parameters:" << endmsg;
  msg(MSG::INFO) << "* prohibitFinalStateDecay = " << m_prohibitFinalStateDecay << endmsg;
  msg(MSG::INFO) << "* prohibitReDecay         = " << m_prohibitReDecay << endmsg;
  msg(MSG::INFO) << "* prohibitUnDecay         = " << m_prohibitUnDecay << endmsg;
  msg(MSG::INFO) << "* prohibitRemoveSelfDecay = " << m_prohibitRemoveSelfDecay << endmsg;
  msg(MSG::INFO) << "* allowAllKnownDecays     = " << m_allowAllKnownDecays << endmsg;
  msg(MSG::INFO) << "* allowDefaultBDecays     = " << m_allowDefaultBDecays << endmsg;
  msg(MSG::INFO) << "User selection parameters:" << endmsg;
  msg(MSG::INFO) << "* applyUserSelection             = " << m_applyUserSelection << endmsg;
  msg(MSG::INFO) << "* userSelRequireOppositeSignedMu = " << m_userSelRequireOppositeSignedMu << endmsg;
  msg(MSG::INFO) << "* userSelMu1MinPt                = " << m_userSelMu1MinPt << endmsg;
  msg(MSG::INFO) << "* userSelMu2MinPt                = " << m_userSelMu2MinPt << endmsg;
  msg(MSG::INFO) << "* userSelMu1MaxEta               = " << m_userSelMu1MaxEta << endmsg;
  msg(MSG::INFO) << "* userSelMu2MaxEta               = " << m_userSelMu2MaxEta << endmsg;
  msg(MSG::INFO) << "* userSelMinDimuMass             = " << m_userSelMinDimuMass << endmsg;
  msg(MSG::INFO) << "* userSelMaxDimuMass             = " << m_userSelMaxDimuMass << endmsg;
 
  // Initialize and print blackList
  m_blackListSet.insert(m_blackList.begin(),m_blackList.end());
  msg(MSG::INFO) << "* blackList;               = ";
  for (std::set<int>::iterator i = m_blackListSet.begin(); i!=m_blackListSet.end(); ++i)
     msg(MSG::INFO) << (*i) << " ";
  msg(MSG::INFO)<< endmsg;
 
  // Initialize and print whiteList
  m_whiteListSet.insert(m_whiteList.begin(),m_whiteList.end());
  msg(MSG::INFO) << "* whiteList               = ";
  for (std::set<int>::iterator i = m_whiteListSet.begin(); i!=m_whiteListSet.end(); ++i)
    msg(MSG::INFO) << (*i) << " ";
  msg(MSG::INFO) << endmsg;
 
  CLHEP::HepRandomEngine* rndmEngine = getRandomEngineDuringInitialize(m_randomStreamName, m_randomSeed, m_dsid);
  // Obtain random number generator for EvtGen
  m_evtAtRndmGen = new EvtInclusiveAtRndmGen(rndmEngine);
 
  // Create an instance of EvtGen and read particle properties and decay files
  EvtExternalGenList genList(true,xmlpath(),"gamma");
  EvtAbsRadCorr* radCorrEngine = genList.getPhotosModel();
  std::list<EvtDecayBase*> extraModels = genList.getListOfModels();
 
   // Create the EvtGen generator object
  // EvtGen myGenerator("decayFile.dec", "evt.pdl", randomEnginePointer,
  //                    radCorrEngine, &extraModels);
 
 
  m_myEvtGen = new EvtGen( m_decayFile.c_str(), m_pdtFile.c_str(), m_evtAtRndmGen, radCorrEngine, &extraModels);
  if(!m_userDecayFile.empty())
    m_myEvtGen->readUDecay(m_userDecayFile.c_str());
 
  return StatusCode::SUCCESS;
}
 
 
void EvtInclusiveDecay::reseedRandomEngine(const std::string& streamName,
                                           const EventContext& ctx)
{
  long seeds[7];
  ATHRNG::calculateSeedsMC21(seeds, streamName,  ctx.eventID().event_number(), m_dsid, m_randomSeed);
  m_evtAtRndmGen->getEngine()->setSeeds(seeds, 0); // NOT THREAD-SAFE
}
 
 
CLHEP::HepRandomEngine* EvtInclusiveDecay::getRandomEngine(const std::string& streamName, unsigned long int randomSeedOffset,
                                                             const EventContext& ctx) const
{
  ATHRNG::RNGWrapper* rngWrapper = m_rndmSvc->getEngine(this, streamName);
  rngWrapper->setSeed( streamName, ctx.slot(), randomSeedOffset, ctx.eventID().run_number() );
  return rngWrapper->getEngine(ctx);
}
 
 
CLHEP::HepRandomEngine* EvtInclusiveDecay::getRandomEngineDuringInitialize(const std::string& streamName, unsigned long int randomSeedOffset, unsigned int conditionsRun, unsigned int lbn) const
{
  const size_t slot=0;
  EventContext ctx;
  ctx.setSlot( slot );
  ctx.setEventID (EventIDBase (conditionsRun,
               EventIDBase::UNDEFEVT,  // event
               EventIDBase::UNDEFNUM,  // timestamp
               EventIDBase::UNDEFNUM,  // timestamp ns
               lbn));
  Atlas::setExtendedEventContext(ctx,
                                 Atlas::ExtendedEventContext( evtStore()->hiveProxyDict(),
                                                              conditionsRun) );
  return getRandomEngine(streamName, randomSeedOffset, ctx);
}
 
 
StatusCode EvtInclusiveDecay::execute(const EventContext& ctx) {
  ATH_MSG_DEBUG("EvtInclusiveDecay executing");
 
  reseedRandomEngine(m_randomStreamName, ctx);
 
  std::string   key = m_inputKeyName;
  // retrieve event from Transient Store (Storegate)
 
  // Load HepMC info
  // FIXME should be using Read/WriteHandles here
  const McEventCollection* oldmcEvtColl{};
  if(m_readExisting) {
    CHECK(evtStore()->retrieve(oldmcEvtColl, key));
    // Fill the new McEventCollection with a copy of the initial HepMC::GenEvent
    m_mcEvtColl = new McEventCollection(*oldmcEvtColl);
  }
  else {CHECK(evtStore()->retrieve(m_mcEvtColl, key));}
 
  if(m_readExisting) {
    if(m_outputKeyName!=key) {
     CHECK(evtStore()->record( m_mcEvtColl,m_outputKeyName));
    }
  }
 
  McEventCollection::iterator mcItr;
  for( mcItr = m_mcEvtColl->begin(); mcItr != m_mcEvtColl->end(); ++mcItr )   {
    HepMC::GenEvent* hepMC = *mcItr;
 
    // Search HepMC record for particles to be decayed by EvtGen
    // NOTE: In order to ensure repeatability, we use customized a std::set to obtain
    //       an ordered list of particles to be decayed by EvtGen.
    std::set<HepMC::GenVertexPtr> visited;
    std::set<HepMC::GenParticlePtr,ParticleIdCompare> toBeDecayed;
    for (auto p: *hepMC) {
      if ( (!p->production_vertex()) ||
           (p->production_vertex()->particles_in_size() == 0) ) {
        StatusCode sc = traverseDecayTree(std::move(p),false,visited,toBeDecayed);
        if (sc.isFailure())
          return StatusCode::FAILURE;
      }
    }
    // Print HepMC in tree format if desired (before doing anything)
    if (m_printHepMCBeforeEvtGen) {
      msg(MSG::INFO) << "Printing HepMC record at " << hepMC << " BEFORE running EvtGen:" << endmsg;
      if (m_printHepMCHighLightTopLevelDecays)
        printHepMC(hepMC,&toBeDecayed);
      else
        printHepMC(hepMC);
    }
 
 
    // Decay selected particles
    bool eventPassesCuts(false);
    int loopCounter(0);
    while( !eventPassesCuts && loopCounter < m_maxNRepeatedDecays ) {
 
      for (auto p: toBeDecayed) {
        if (p == 0) {
          msg(MSG::ERROR ) << "Overlapping decay tree for particle" << p <<endmsg;
          return StatusCode::FAILURE;
        }
        decayParticle(hepMC,std::move(p));
        HepMC::fillBarcodesAttribute(hepMC);
      }
 
      if(m_applyUserSelection)
        eventPassesCuts = passesUserSelection(hepMC);
      else
        eventPassesCuts = true;
 
      m_nRepeatedDecays++;
      loopCounter++;
    }
 
    // Store the number of decay attempts in event weights std::map, only if repeated decays enabled
 
    if(m_maxNRepeatedDecays > 1) {
      hepMC->weight("nEvtGenDecayAttempts") = loopCounter;
    }
    // Print HepMC in tree format if desired (after finishing all EvtGen decays)
    if (m_printHepMCAfterEvtGen) {
      msg(MSG::INFO)  << "Printing HepMC record at " << hepMC << " AFTER running EvtGen:" << endmsg;
      if (m_printHepMCHighLightTopLevelDecays)
        printHepMC(hepMC,&toBeDecayed);
      else
        printHepMC(hepMC);
    }
  }
 
  if(m_readExisting && m_outputKeyName==key) {
    CHECK(evtStore()->overwrite(m_mcEvtColl, m_outputKeyName));
  }
 
  return StatusCode::SUCCESS;
}
 
 
StatusCode EvtInclusiveDecay::finalize() {
 
  if (m_checkDecayChannels) {
    ATH_MSG_INFO("The following particles were checked and didn't have any decay channels:");
    if (msgLvl(MSG::INFO)) {
      std::cout << std::endl;
      std::cout << " Particle code        # Occurences" << std::endl;
      std::cout << "----------------------------------"  << std::endl;
      for (std::map<int,long>::iterator p = m_noDecayChannels.begin(); p!=m_noDecayChannels.end(); ++p) {
        int id = p->first;
        int count = p->second;
        std::cout << std::setw(14) << id
                  << std::setw(20) << count
                  << std::endl;
      }
      std::cout << std::endl;
    }
  }
  ATH_MSG_INFO("Total number of repeated decays: " << m_nRepeatedDecays);
  ATH_MSG_INFO("EvtInclusiveDecay finalized");
  return StatusCode::SUCCESS;
}
 
 
 
//
// Recursively traverse the decay tree of a particle p, looking for particles to be
// decayed by EvtGen. Care is taken to traverse each particle only once.
// Note that since in each decay tree only the top-most particle will be decayed
// by EvtGen (with its decay tree being deleted beforehand), we cannot use HepMC's
// "descendant" iterator.
//
StatusCode EvtInclusiveDecay::traverseDecayTree(HepMC::GenParticlePtr p,
                                                bool isToBeRemoved,
                                                std::set<HepMC::GenVertexPtr>& visited,
                                                std::set<HepMC::GenParticlePtr,ParticleIdCompare>& toBeDecayed) {
  ATH_MSG_VERBOSE("Inspecting: " << pdgName(p) << " " << p);
  if (!isToBeRemoved) {
    if (isToBeDecayed(p,true)) {
      toBeDecayed.insert(p);
      isToBeRemoved = true;
      ATH_MSG_VERBOSE("Selected particle for decay: " << pdgName(p) << " " << p );
 
      // In principle we could stop the recursion here. However, to prevent
      // pathological cases in certain decay trees (in particular from Herwig),
      // we continue in order to mark all descendants of this particle
      // as visited. Thus none of these descendants can be flagged for further
      // decay, even if it has several mothers.
    }
  }
  auto v = p->end_vertex();
  if (v) {
    if (visited.insert(v).second) {
      if ( isToBeRemoved && (v->particles_in_size()>1) && m_checkDecayTree ) {
        ATH_MSG_WARNING("Found particle to be decayed with vertex with >1 incoming mother particles in decay tree");
        ATH_MSG_WARNING( ([&p, &v](){  std::stringstream ss;   HepMC::Print::line(ss,p); HepMC::Print::line(ss,v);  return ss.str();})());
      }
      for (auto itp: *v) {
        ATH_CHECK(traverseDecayTree(std::move(itp),isToBeRemoved,visited,toBeDecayed) );
      }
 
    }
  }
  return StatusCode::SUCCESS;
}
 
 
 
//
// Remove an existing decay tree
//
void EvtInclusiveDecay::removeDecayTree(HepMC::GenEvent* hepMC, HepMC::GenParticlePtr p) {
  auto v = p->end_vertex();
  if (v) {
    //This is recursive in HepMC3. But explicit deletion is allowed as well.
    hepMC->remove_vertex(std::move(v));
    p->set_status(1);   // For now, flag particle as undecayed (stable)
    ATH_MSG_DEBUG("Removed existing " << pdgName(p) << " " << p  );
  }
}
 
 
 
//
// Decay a particle with EvtGen. Any existing decay tree will be removed.
//
// The following status codes are used:
//
// status == 1     - undecayed particle (also for particles that are not supposed to decay)
// status == 2   - particle decayed by EvtGen
// status == 0   - error, particle was supposed to be decayed by EvtGen, but found no decay channel
//
// Note that if a particle with an existing decay tree but no defined decay channels
// in EvtGen is passed to this routine, the net effect will be to "undecay" this
// particle. The particle will be flagged by status code 899, but MAY BE LOST further
// downstream in the simulation chain. The default job parameters are for routine
// isToBeDecayed() to never enable decays of such particles by EvtGen.
//
void EvtInclusiveDecay::decayParticle(HepMC::GenEvent* hepMC, HepMC::GenParticlePtr part) {
  ATH_MSG_DEBUG("Decaying particle " << pdgName(part) << " " << part);
  if (msgLvl(MSG::VERBOSE)) HepMC::Print::line(std::cout,part);
 
  // Remove existing decay tree, if any, and flag particle as being decayed by EvtGen
  removeDecayTree(hepMC,part);
  part->set_status(0);
 
  // Create EvtGen version of part and have EvtGen decay it.
  // Since EvtGen uses GeV, convert particles momentum from MeV to GeV.
  int id = part->pdg_id();
  EvtId evtId=EvtPDL::evtIdFromStdHep(id);
  double en =(part->momentum()).e()/1000.;
  double px=(part->momentum()).px()/1000.;
  double py=(part->momentum()).py()/1000.;
  double pz=(part->momentum()).pz()/1000.;
  EvtVector4R evtP(en,px,py,pz);
  EvtParticle* evtPart = EvtParticleFactory::particleFactory(evtId,evtP);
  
  // set transverse polarization to vector mesons (relevant for coherent production of J/Psi etc in UPC)
  if(m_setVMtransversePol && (id==113 || id== 443 || id==100443 || id==553 || id==100553 || id==200553) )evtPart->setVectorSpinDensity();
  
  m_myEvtGen->generateDecay(evtPart);
  if (msgLvl(MSG::VERBOSE)) evtPart->printTree();
  double ct_s = part->production_vertex()->position().t();
  double x_s = part->production_vertex()->position().x();
  double y_s = part->production_vertex()->position().y();
  double z_s = part->production_vertex()->position().z();
 
  EvtVector4R treeStart(ct_s,x_s,y_s,z_s);
  // Add new decay tree to hepMC, converting back from GeV to MeV.
  addEvtGenDecayTree(hepMC, part, evtPart, treeStart, 1000.);
  if(evtPart->getNDaug() !=0) part->set_status(2);
  evtPart->deleteTree();
}
 
 
 
void EvtInclusiveDecay::addEvtGenDecayTree(HepMC::GenEvent* hepMC, HepMC::GenParticlePtr part,
                                           EvtParticle* evtPart, EvtVector4R treeStart, double momentumScaleFactor) {
  if(evtPart->getNDaug()!=0) {
    // Add decay vertex, starting from production vertex of particle
    double ct=(evtPart->getDaug(0)->get4Pos()).get(0)+treeStart.get(0);
    double x=(evtPart->getDaug(0)->get4Pos()).get(1)+treeStart.get(1);
    double y=(evtPart->getDaug(0)->get4Pos()).get(2)+treeStart.get(2);
    double z=(evtPart->getDaug(0)->get4Pos()).get(3)+treeStart.get(3);
 
    HepMC::GenVertexPtr end_vtx = HepMC::newGenVertexPtr(HepMC::FourVector(x,y,z,ct));
 
    hepMC->add_vertex(end_vtx);
    end_vtx->add_particle_in(std::move(part));
 
    // Add decay daughter with their own decay trees
    for(uint it=0; it<evtPart->getNDaug(); it++) {
      double e=(evtPart->getDaug(it)->getP4Lab()).get(0) * momentumScaleFactor;
      double px=(evtPart->getDaug(it)->getP4Lab()).get(1) * momentumScaleFactor;
      double py=(evtPart->getDaug(it)->getP4Lab()).get(2) * momentumScaleFactor;
      double pz=(evtPart->getDaug(it)->getP4Lab()).get(3) * momentumScaleFactor;
      int id=EvtPDL::getStdHep(evtPart->getDaug(it)->getId());
      int status=1;
      if(evtPart->getDaug(it)->getNDaug() != 0) status=2;
      HepMC::GenParticlePtr daughter = HepMC::newGenParticlePtr(HepMC::FourVector(px,py,pz,e),id,status);
      end_vtx->add_particle_out(daughter);
      addEvtGenDecayTree(hepMC, std::move(daughter), evtPart->getDaug(it), treeStart, momentumScaleFactor);
    }
  }
}
 
 
 
//
// isToBeDecayed returns true if we want the particle p to be decayed by
// EvtGen based on the job options selected by the user.
// The parameter doCrossChecks is used to prevent double-counting for cross-checks
// if isToBeDecayed is called more than once for the same particle.
//
bool EvtInclusiveDecay::isToBeDecayed(HepMC::ConstGenParticlePtr p, bool doCrossChecks) {
  int id = p->pdg_id();
  int nDaughters = 0;
  auto v = p->end_vertex();
  if (v) nDaughters = v->particles_out_size();
 
  // Ignore documentation lines
  if (p->status() == 3) return false;
  // And any particles that aren't stable or decayed
  if(!m_isfHerwig && !MC::isPhysical(p)) return false;
 
  // Particularly for Herwig, try to ignore particles that really should
  // be flagged as documentation lines
  double m2 = p->momentum().m2();
  if (m2 < -1.0E-3) {
    ATH_MSG_DEBUG("Ignoring particle " << pdgName(std::move(p)) << " with m^2 = " << m2);
    return false;
  }
 
  // Check whether EvtGen has any decay channels defined for this particle
  EvtId evtId = EvtPDL::evtIdFromStdHep(id);
  // std::cout << "EVTID: " << evtId.getId() << " alias " << evtId.getAlias() << std::endl;
  int nModes = 0;
  if (evtId.getId()>=0)
    //    nModes = EvtDecayTable::getNMode(evtId.getAlias());
    nModes = EvtDecayTable::getInstance()->getNMode(evtId.getAlias());
  if (doCrossChecks) {
    ATH_MSG_VERBOSE("Checking particle " << pdgName(p)
        << " (status = " << p->status()
                    <<") -- " << nModes << " decay modes found");
    if (m_checkDecayChannels && nModes==0) {
      std::map<int,long>::iterator pos = m_noDecayChannels.find(id);
      if (pos != m_noDecayChannels.end())
        (pos->second)++;
      else
        m_noDecayChannels[id] = 1;
    }
  }
 
  // Check prohibit* settings
  if (m_prohibitFinalStateDecay && MC::isStable(p)) return false;
  if (m_prohibitReDecay && nDaughters>0) return false;
  if (m_prohibitUnDecay && nModes==0) return false;
  if (m_prohibitRemoveSelfDecay && nDaughters>0) {
    // For now, check only children - this should be sufficient and checking all
    // descendants would be very expensive.
    for (auto  itd: *v) {
      if (std::abs(itd->pdg_id()) == std::abs(id)) return false;
    }
  }
 
  // Check blackList
  if (m_blackListSet.count(std::abs(id))>0) return false;
 
  // Check allow* settings
  if (m_allowAllKnownDecays && nModes>0) return true;
  if (m_allowDefaultBDecays && isDefaultB(id)) return true;
 
  // Check whiteList
  if (m_whiteListSet.count(std::abs(id))>0) return true;
 
  return false;   // Default is NOT to decay through EvtGen
}
 
 
 
//
// The following mimicks the particle selection implemented in EvtDecay.
//
bool EvtInclusiveDecay::isDefaultB(const int pId) const {
  int id = std::abs(pId);
  if ( id == 511   ||
       id == 521   ||
       id == 531   ||
       id == 541   ||
       id == 5122  ||
       id == 5132  ||
       id == 5232  ||
       id == 5112  ||
       id == 5212  ||
       id == 5222 )
    return true;
  else
    return false;
}
 
//
// Function to apply the user selection after repeated decay
// Now the selection is based on di-muon kinematics only
// TODO: to be replaced by something more configurable
//
bool EvtInclusiveDecay::passesUserSelection(HepMC::GenEvent* hepMC) {
  bool passed(false);
  std::vector<HepMC::GenParticlePtr> *muons = new std::vector<HepMC::GenParticlePtr>;
 
  for ( const auto& p:  *hepMC) {
    if( std::abs(p->pdg_id()) == 13 )
      muons->push_back(p);
  }
 
  for (auto muItr1 = muons->begin(); muItr1 != muons->end(); ++muItr1) {
    for (auto muItr2 = muItr1+1; muItr2 != muons->end(); ++muItr2) {
      if( m_userSelRequireOppositeSignedMu && (*muItr1)->pdg_id() * (*muItr2)->pdg_id() > 0)
        continue;
      if( !( (*muItr1)->momentum().perp() > m_userSelMu1MinPt && std::abs((*muItr1)->momentum().pseudoRapidity()) < m_userSelMu1MaxEta &&
             (*muItr2)->momentum().perp() > m_userSelMu2MinPt && std::abs((*muItr2)->momentum().pseudoRapidity()) < m_userSelMu2MaxEta ) &&
          !( (*muItr2)->momentum().perp() > m_userSelMu1MinPt && std::abs((*muItr2)->momentum().pseudoRapidity()) < m_userSelMu1MaxEta &&
             (*muItr1)->momentum().perp() > m_userSelMu2MinPt && std::abs((*muItr1)->momentum().pseudoRapidity()) < m_userSelMu2MaxEta ) )
        continue;
      double dimuMass = invMass((*muItr1),(*muItr2));
      if( !( dimuMass > m_userSelMinDimuMass && (dimuMass < m_userSelMaxDimuMass || m_userSelMaxDimuMass < 0.) ) )
        continue;
      passed = true;
    }
  }
 
  delete muons;
 
  return passed;
}
 
double EvtInclusiveDecay::invMass(HepMC::ConstGenParticlePtr p1, HepMC::ConstGenParticlePtr p2) {
  double p1Px = p1->momentum().px();
  double p1Py = p1->momentum().py();
  double p1Pz = p1->momentum().pz();
  double p1E  = p1->momentum().e();
  double p2Px = p2->momentum().px();
  double p2Py = p2->momentum().py();
  double p2Pz = p2->momentum().pz();
  double p2E  = p2->momentum().e();
  double dimuE = p2E + p1E;
  double dimuPx = p2Px + p1Px;
  double dimuPy = p2Py + p1Py;
  double dimuPz = p2Pz + p1Pz;
  double invMass = std::sqrt(dimuE*dimuE - dimuPx*dimuPx - dimuPy*dimuPy - dimuPz*dimuPz);
 
  return invMass;
}
 
//
// Utility functions to print a HepMC event record in a tree-like format, using
// colors to denote the status of particles and to indicate which particles
// are selected by the job options to be decayed by EvtGen.
//
 
void EvtInclusiveDecay::printHepMC(HepMC::GenEvent* hepMC, std::set<HepMC::GenParticlePtr,ParticleIdCompare>* particleSet) {
  std::set<HepMC::GenVertexPtr> visited;
  unsigned int nParticlesFound = 0;
  unsigned int nTreesFound = 0;
  for (auto p: *hepMC) {
    if ( (!p->production_vertex()) ||
         (p->production_vertex()->particles_in_size() == 0) ) {
      nTreesFound++;
      std::cout << "\n    Found new partial decay tree:\n" << std::endl;
      unsigned int nParticlesVisited = printTree(std::move(p),visited,1,particleSet);
      std::cout << "\n    " << nParticlesVisited << " particles in this subtree" << std::endl;
      nParticlesFound += nParticlesVisited;
    }
  }
  std::cout << "\n    Total of " << nParticlesFound << " particles found in "
            << nTreesFound << " decay subtrees in HepMC event record\n" << std::endl;
}
 
unsigned int EvtInclusiveDecay::printTree(HepMC::GenParticlePtr p, std::set<HepMC::GenVertexPtr>& visited, int level, std::set<HepMC::GenParticlePtr,ParticleIdCompare>* particleSet) {
 
  unsigned int nParticlesVisited = 1;
  for (int i=0; i<level; i++) std::cout << "    ";
  std::cout << pdgName(p,m_printHepMCHighlighted,particleSet);
  auto v = p->end_vertex();
  if (v) {
    if (v->particles_in_size() > 1)
      std::cout << " [interaction: " << v->particles_in_size() << " particles, vertex " << v << "]    -->   ";
    else
      std::cout << "   -->   ";
    if (visited.insert(v).second) {
      for (auto itp: *v) {
        std::cout << pdgName(itp,m_printHepMCHighlighted,particleSet) << "   ";
      }
      std::cout << std::endl;
      for (auto itp: *v) {
        if (itp->end_vertex())
          nParticlesVisited += printTree(std::move(itp), visited, level+1, particleSet);
        else
          nParticlesVisited++;
      }
    } else
      std::cout << "see above" << std::endl;
  } else
    std::cout << "   no decay vertex\n" << std::endl;
  return nParticlesVisited;
}
 
std::string EvtInclusiveDecay::pdgName(HepMC::ConstGenParticlePtr p, bool statusHighlighting, std::set<HepMC::GenParticlePtr,ParticleIdCompare>* particleSet) {
  std::ostringstream buf;
  bool inlist = false;
  if (particleSet) for (const auto& pinl: *particleSet) if (pinl&&p) if (pinl.get() == p.get()) inlist=true;
  if (statusHighlighting) {
    if ( ((particleSet!=0) && (inlist)) ||
         ((particleSet==0) && isToBeDecayed(p,false)) )
      buf << "\033[7m";   // reverse
    if (p and !MC::isStable(p)) {
      if (MC::isDecayed(p))
        buf << "\033[33m";   // yellow
      else
        buf << "\033[31m";   // red
    }
  }
  if (p){
    buf << p->pdg_id();
    if (statusHighlighting) {
      buf << "\033[0m";   // revert color attributes
    }
  }
  return buf.str();
}
 
 
//
// Interface between Athena random number service and EvtGen's EvtRandomEngine class
//
EvtInclusiveAtRndmGen::EvtInclusiveAtRndmGen(CLHEP::HepRandomEngine* engine)
  : m_engine(engine)
{}
 
double EvtInclusiveAtRndmGen::random() {
  return CLHEP::RandFlat::shoot(m_engine);
}

 
std::string EvtInclusiveDecay::xmlpath(){
  return PathResolverFindCalibDirectory( "Pythia8/xmldoc" );
}