JetSecVtxFindingAlg.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
#include "BTagging/JetSecVtxFindingAlg.h"
 
#include "StoreGate/ReadDecorHandle.h"
#include "StoreGate/ReadHandle.h"
 
namespace Analysis {
 
  JetSecVtxFindingAlg::JetSecVtxFindingAlg(const std::string& name, ISvcLocator* pSvcLocator):
    AthReentrantAlgorithm(name,pSvcLocator),
    m_secVertexFinderToolHandle(this)
  {
    //List of the secondary vertex finders in jet to be run
    declareProperty("SecVtxFinder",          m_secVertexFinderToolHandle);
  }
 
  StatusCode JetSecVtxFindingAlg::initialize()
  {
    // This will check that the properties were initialized properly
    // by job configuration.
    m_TracksToTag = m_JetCollectionName.key() + "." + m_TracksToTag.key();
 
    ATH_CHECK( m_JetCollectionName.initialize() );
    ATH_CHECK( m_TracksToTag.initialize() );
    ATH_CHECK( m_VertexCollectionName.initialize() );
    ATH_CHECK( m_VxSecVertexInfoName.initialize() );
 
    /* ----------------------------------------------------------------------------------- */
    /*                        RETRIEVE SERVICES FROM STOREGATE                             */
    /* ----------------------------------------------------------------------------------- */
 
    if ( m_secVertexFinderToolHandle.retrieve().isFailure() ) {
      ATH_MSG_ERROR("#BTAG# Failed to retrieve " << m_secVertexFinderToolHandle);
    } else {
      ATH_MSG_DEBUG("#BTAG# Retrieved " << m_secVertexFinderToolHandle);
    }
 
    return StatusCode::SUCCESS;
  }
 
 
  StatusCode JetSecVtxFindingAlg::execute(const EventContext& ctx) const {
    //retrieve the Jet container
    SG::ReadHandle<xAOD::JetContainer> h_JetCollectionName (m_JetCollectionName, ctx);
    if (!h_JetCollectionName.isValid()) {
      ATH_MSG_ERROR( " cannot retrieve jet container with key " << m_JetCollectionName.key()  );
      return StatusCode::FAILURE;
    }
 
    /* Record the VxSecVertexInfo output container */
    SG::WriteHandle<Trk::VxSecVertexInfoContainer> h_VxSecVertexInfoName (m_VxSecVertexInfoName, ctx);
    ATH_CHECK( h_VxSecVertexInfoName.record(std::make_unique<Trk::VxSecVertexInfoContainer>()));
 
    if (h_JetCollectionName->empty()) {
      ATH_MSG_DEBUG("#BTAG# Empty Jet collection");
      return StatusCode::SUCCESS;
    }
 
    SG::ReadDecorHandle<xAOD::JetContainer, std::vector<ElementLink< xAOD::IParticleContainer> > >
      h_TracksToTag (m_TracksToTag, ctx);
 
    if (!h_TracksToTag.isAvailable()) {
      ATH_MSG_ERROR( "cannot retrieve jet container particle EL decoration with key " << h_TracksToTag.decorKey()  );
      return StatusCode::FAILURE;
    }
 
    const xAOD::Vertex* primaryVertex(nullptr);
 
    //retrieve primary vertex
    SG::ReadHandle<xAOD::VertexContainer> h_VertexCollectionName (m_VertexCollectionName, ctx);
    if (!h_VertexCollectionName.isValid()) {
        ATH_MSG_ERROR( " cannot retrieve primary vertex container with key " << m_VertexCollectionName.key()  );
        return StatusCode::FAILURE;
    }
    unsigned int nVertexes = h_VertexCollectionName->size();
    if (nVertexes == 0) {
      ATH_MSG_DEBUG("#BTAG#  Vertex container is empty");
      return StatusCode::SUCCESS;
    }
    for (const auto *fz : *h_VertexCollectionName) {
      if (fz->vertexType() == xAOD::VxType::PriVtx) {
          primaryVertex = fz;
          break;
      }
    }
 
 
    if (! primaryVertex) {
      ATH_MSG_DEBUG("#BTAG#  No vertex labeled as VxType::PriVtx!");
      xAOD::VertexContainer::const_iterator fz = h_VertexCollectionName->begin();
      primaryVertex = *fz;
        if (primaryVertex->nTrackParticles() == 0) {
          ATH_MSG_DEBUG("#BTAG#  PV==BeamSpot: probably poor tagging");
        }
    }
 
    const xAOD::Vertex& PrimaryVtx = *primaryVertex;
 
    for (const auto *jetIter : *h_JetCollectionName) {
      const xAOD::Jet& jetToTag = *jetIter;
 
      const std::vector<ElementLink< xAOD::IParticleContainer > >& tracksInJet
        = h_TracksToTag(jetToTag);
 
      if(tracksInJet.empty()){
        ATH_MSG_DEBUG("#BTAG# No track in Jet");
        h_VxSecVertexInfoName->push_back(nullptr);
        continue;
      } 
 
      std::vector<const xAOD::IParticle*> inputIParticles;
       
 
      inputIParticles.reserve(tracksInJet.size());
      for (const auto& iparticle : tracksInJet)
        inputIParticles.push_back(*iparticle);
 
      ATH_MSG_DEBUG("#BTAG#  Running " << m_secVertexFinderToolHandle);
 
      Trk::VxSecVertexInfo* myVertexInfo = m_secVertexFinderToolHandle->findSecVertex(PrimaryVtx, jetIter->p4(), inputIParticles);
      ATH_MSG_DEBUG("#BTAG# Number of vertices found: " << myVertexInfo->vertices().size());
      h_VxSecVertexInfoName->push_back(myVertexInfo); 
    }// for loop on jets
 
    return StatusCode::SUCCESS;
  } 
 
} // namespace