RedoTruthLinksAlg.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
#include "AthenaKernel/errorcheck.h"
 
#include "xAODTruth/TruthEvent.h"
#include "xAODTruth/TruthEventContainer.h"
#include "StoreGate/ReadHandle.h"
#include "StoreGate/WriteHandle.h"
 
#include "RedoTruthLinksAlg.h"
 
 
using namespace std;
 
namespace xAODMaker {
    
    
    RedoTruthLinksAlg::RedoTruthLinksAlg( const string& name, ISvcLocator* svcLoc )
    : AthAlgorithm( name, svcLoc )
    {
    }
    
    
    StatusCode RedoTruthLinksAlg::initialize() {
        
    // initialize handles
    ATH_CHECK(m_truthLinkContainerKey.initialize());
    ATH_CHECK(m_linksOnlyTruthEventContainerKey.initialize());
 
        ATH_MSG_DEBUG("xAOD linksOnlyTruthEventContainer name = " << m_linksOnlyTruthEventContainerKey.key() );
        ATH_MSG_DEBUG("xAOD TruthParticleLinksContainer name = " << m_truthLinkContainerKey.key());
 
 
        return StatusCode::SUCCESS;
    }
    
    
    StatusCode RedoTruthLinksAlg::execute() {
        
    SG::WriteHandle<xAODTruthParticleLinkVector> truthLinkVec(m_truthLinkContainerKey);
    ATH_CHECK(truthLinkVec.record(std::make_unique<xAODTruthParticleLinkVector>()));
        
            
    SG::ReadHandle<xAOD::TruthEventContainer> xTruthEventContainer(m_linksOnlyTruthEventContainerKey);
    // validity check is only really needed for serial running. Remove when MT is only way.
    if (!xTruthEventContainer.isValid()) {
      ATH_MSG_ERROR("Could not retrieve xAOD::TruthEventContainer with key:" << 
            m_linksOnlyTruthEventContainerKey.key());
      return StatusCode::FAILURE;
    } else {
      ATH_MSG_DEBUG( "Retrieved for reading xAOD::TruthEventContainer key: " <<
             m_linksOnlyTruthEventContainerKey.key());
    }
    // Loop over events and particles
    for (const xAOD::TruthEvent* evt : *xTruthEventContainer) {
      for (const auto& par : evt->truthParticleLinks()) {
        if ( !par.isValid() ) {
          // This can happen if particles have been thinned.
          ATH_MSG_VERBOSE("Found invalid particle element link in TruthEvent"); //< @todo Use HepMC evt number?
          continue;
        }
        // Create link between HepMC and xAOD truth
        truthLinkVec->push_back(new xAODTruthParticleLink(HepMcParticleLink(HepMC::barcode(*par), 0, HepMcParticleLink::IS_POSITION, HepMcParticleLink::IS_BARCODE), par)); // FIXME is barcode-based - using barcodes until xAOD::TruthParticle::id() is available
      }
    }
        
        std::stable_sort(truthLinkVec->begin(), truthLinkVec->end(), SortTruthParticleLink());
        ATH_MSG_VERBOSE("Summarizing truth link size: " << truthLinkVec->size() );
        
        return StatusCode::SUCCESS;
    }
        
} // namespace xAODMaker