xAODVertexRetriever.cxx

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
 
#include "xAODJiveXML/xAODVertexRetriever.h"
 
#include "xAODTracking/VertexContainer.h"
#include "xAODTracking/VertexAuxContainer.h"
#include "xAODTracking/TrackParticleContainer.h"
#include "xAODTracking/TrackParticleAuxContainer.h"
 
#include "AthenaKernel/Units.h"
using Athena::Units::cm;
 
namespace JiveXML {
 
  xAODVertexRetriever::xAODVertexRetriever(const std::string& type,const std::string& name,const IInterface* parent):
    AthAlgTool(type,name,parent){}
 
 
   StatusCode xAODVertexRetriever::initialize(){
    ATH_CHECK(m_keys.initialize());
    return StatusCode::SUCCESS;
  }
 
  
  StatusCode xAODVertexRetriever::retrieve(ToolHandle<IFormatTool> &FormatTool) {
 
    ATH_MSG_DEBUG("In retrieve()");
 
    // Loop through the keys and retrieve the corresponding data
    for (const auto& key : m_keys) {
      SG::ReadHandle<xAOD::VertexContainer> cont(key);
      if (cont.isValid()) {
    DataMap data = getData(&(*cont));
    if (FormatTool->AddToEvent(dataTypeName(), key.key() + "_xAOD", &data).isFailure()) {
      ATH_MSG_WARNING("Failed to add collection " << key.key());
    } else {
      ATH_MSG_DEBUG(" (" << key.key() << ") retrieved");
    }
      } else {
    ATH_MSG_WARNING("Collection " << key.key() << " not found in SG");
      }
    }
 
    return StatusCode::SUCCESS;
  }
 
  const DataMap xAODVertexRetriever::getData(const xAOD::VertexContainer* cont) {
 
    ATH_MSG_DEBUG("in getData()");
 
    float chi2val = 0.;
 
    DataMap DataMap;
 
    DataVect x;
    DataVect y;
    DataVect z;
    DataVect chi2;
    DataVect vertexType;
    DataVect primVxCand;
    DataVect covMatrix;
    DataVect numTracks;
    DataVect tracks;
    DataVect sgkey;
 
    //Get size of current container
    xAOD::VertexContainer::size_type NVtx = cont->size();
 
    x.reserve(x.size()+NVtx);
    y.reserve(y.size()+NVtx);
    z.reserve(z.size()+NVtx);
    chi2.reserve(chi2.size()+NVtx);
    vertexType.reserve(vertexType.size()+NVtx);
    primVxCand.reserve(primVxCand.size()+NVtx);
    covMatrix.reserve(covMatrix.size()+NVtx);
    numTracks.reserve(numTracks.size()+NVtx);
    tracks.reserve(tracks.size()+NVtx);
    sgkey.reserve(sgkey.size()+NVtx);
 
    int counter = 0;
 
    //Loop over vertices
    xAOD::VertexContainer::const_iterator VertexItr = cont->begin();
    for ( ; VertexItr != cont->end(); ++VertexItr) {
 
      ATH_MSG_DEBUG("  Vertex #" << counter++ << " : x = "  << (*VertexItr)->x()/cm << ", y = "
            << (*VertexItr)->y()/cm << ", z[GeV] = "  << (*VertexItr)->z()/cm
            << ", vertexType = "  << (*VertexItr)->vertexType()
            << ", chiSquared = "  << (*VertexItr)->chiSquared()
            << ", numberDoF = "  << (*VertexItr)->numberDoF());
 
      x.emplace_back(DataType((*VertexItr)->x()/cm));
      y.emplace_back(DataType((*VertexItr)->y()/cm));
      z.emplace_back(DataType((*VertexItr)->z()/cm));
 
      vertexType.emplace_back( DataType((*VertexItr)->vertexType()));
    
      if ((*VertexItr)->vertexType() == 1 ){
    primVxCand.emplace_back( 1 );
      }else{
    primVxCand.emplace_back( 0 );
      }
      sgkey.emplace_back (m_tracksName.value());
 
      covMatrix.emplace_back(DataType("2 -.1 .5 -.01 0.002 .01"));
 
      //degrees of freedom might be zero - beware
      if ( (*VertexItr)->numberDoF()  != 0 ){
    chi2val = (*VertexItr)->chiSquared()/(*VertexItr)->numberDoF() ;
      }else{
    chi2val = -1.;
      }
      chi2.emplace_back(DataType( chi2val ));
 
      // track-vertex association code in xAOD from Nick Styles, Apr14:
      // InnerDetector/InDetRecAlgs/InDetPriVxFinder/InDetVxLinksToTrackParticles
 
      int trkCnt = 0;
      const std::vector< ElementLink< xAOD::TrackParticleContainer > > tpLinks =  (*VertexItr)->trackParticleLinks();
 
      //iterating over the links
      unsigned int tp_size = tpLinks.size();
      numTracks.emplace_back(DataType( tp_size ));
      if(tp_size){ // links exist
    for(unsigned int tp = 0; tp<tp_size; ++tp)
      {
        ElementLink< xAOD::TrackParticleContainer >  tpl = tpLinks.at(tp);
 
        ATH_MSG_DEBUG("  Vertex #" << counter << " track association index: " << tpl.index()
              << ", collection : "  << tpl.key()
              << ", Tracks : " << tp  << " out of " << tp_size << ", own count: " << trkCnt++);
 
        if ( tpl.index() < 1000 ){ // sanity check, this can be huge number
          tracks.emplace_back(DataType( tpl.index() ));
        }else{
          tracks.emplace_back(DataType( 0 ));
        }
      } //links exist
      }//end of track particle collection size check
 
    } // end VertexIterator
 
      // four-vectors
    DataMap["x"] = x;
    DataMap["y"] = y;
    DataMap["z"] = z;
    DataMap["chi2"] = chi2;
    DataMap["vertexType"] = vertexType;
    DataMap["primVxCand"] = primVxCand;
    DataMap["covMatrix multiple=\"6\""] = covMatrix;
    DataMap["numTracks"] = numTracks;
    DataMap["sgkey"] = sgkey;
 
    //This is needed once we know numTracks and associations:
    //If there had been any tracks, add a tag
    if ((numTracks.size()) != 0){
      //Calculate average number of tracks per vertex
      double NTracksPerVertex = tracks.size()*1./numTracks.size();
      std::string tag = "tracks multiple=\"" +DataType(NTracksPerVertex).toString()+"\"";
      DataMap[tag] = tracks;
    }
 
    ATH_MSG_DEBUG(dataTypeName() << " retrieved with " << x.size() << " entries");
 
    return DataMap;
 
  }
 
 
} // JiveXML namespace