PFLCNeutralFlowElementCreatorAlgorithm.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
#include "PFLCNeutralFlowElementCreatorAlgorithm.h"
#include "xAODCore/ShallowCopy.h"
#include "xAODCaloEvent/CaloClusterContainer.h"
 
StatusCode PFLCNeutralFlowElementCreatorAlgorithm::initialize(){
 
  ATH_CHECK(m_neutralFEContainerReadHandleKey.initialize());
  ATH_CHECK(m_neutralFELCContainerWriteHandleKey.initialize());
 
  return StatusCode::SUCCESS;
}
 
StatusCode PFLCNeutralFlowElementCreatorAlgorithm::execute(const EventContext& ctx) const {
 
  ATH_MSG_DEBUG("Executing");
 
  /* Create Neutral PFOs from all eflowCaloObjects */
  SG::ReadHandle<xAOD::FlowElementContainer> neutralFEContainerReadHandle(m_neutralFEContainerReadHandleKey,ctx);
 
  xAOD::ShallowCopyResult_t<xAOD::FlowElementContainer> shallowCopyPair =
    xAOD::shallowCopy(*neutralFEContainerReadHandle, ctx);
 
  SG::WriteHandle<xAOD::FlowElementContainer> neutralFELCContainerWriteHandle(m_neutralFELCContainerWriteHandleKey,ctx);
  ATH_CHECK( neutralFELCContainerWriteHandle.record(std::move(shallowCopyPair.first),std::move(shallowCopyPair.second)));
 
  for( unsigned int counter = 0; counter < (*neutralFEContainerReadHandle).size(); counter++){
    const xAOD::FlowElement* thisFE = (*neutralFEContainerReadHandle)[counter];
 
    const static SG::Accessor<ElementLink<xAOD::CaloClusterContainer> > accShowerSubtractedClusterLink("FEShowerSubtractedClusterLink");
    const ElementLink<xAOD::CaloClusterContainer>& clusElementLink = accShowerSubtractedClusterLink(*thisFE);
 
    xAOD::FlowElement* theCopiedFE = (*neutralFELCContainerWriteHandle)[counter];
    //be careful here - cluster p4 methods do not store sign. Thus -ve energy clusters have +ve pt and hence +ve energy
    //we use eta,phi at EM scale for both 4-vectors - standard FE are at EM scale
    theCopiedFE->setP4((*clusElementLink)->pt(), (*clusElementLink)->rawEta(), (*clusElementLink)->rawPhi(), (*clusElementLink)->m());
  }
 
 
  return StatusCode::SUCCESS;
}