GSFAndHGCalLinker.cc

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#include "RecoParticleFlow/PFProducer/interface/BlockElementLinkerBase.h"
#include "DataFormats/ParticleFlowReco/interface/PFCluster.h"
#include "DataFormats/ParticleFlowReco/interface/PFBlockElementCluster.h"
#include "DataFormats/ParticleFlowReco/interface/PFBlockElementGsfTrack.h"
#include "RecoParticleFlow/PFClusterTools/interface/LinkByRecHit.h"

class GSFAndHGCalLinker : public BlockElementLinkerBase {
public:
  GSFAndHGCalLinker(const edm::ParameterSet& conf) :
    BlockElementLinkerBase(conf),
    _useKDTree(conf.getParameter<bool>("useKDTree")),
    _debug(conf.getUntrackedParameter<bool>("debug",false)) {}
  
  double testLink 
  ( const reco::PFBlockElement*,
    const reco::PFBlockElement* ) const override;

private:
  bool _useKDTree,_debug;
};

DEFINE_EDM_PLUGIN(BlockElementLinkerFactory, 
          GSFAndHGCalLinker, 
          "GSFAndHGCalLinker");

double GSFAndHGCalLinker::testLink
  ( const reco::PFBlockElement* elem1,
    const reco::PFBlockElement* elem2) const {  
  constexpr reco::PFTrajectoryPoint::LayerType ECALShowerMax =
    reco::PFTrajectoryPoint::ECALShowerMax;
  const reco::PFBlockElementCluster  *hgcalelem(nullptr);
  const reco::PFBlockElementGsfTrack *gsfelem(nullptr);
  double dist(-1.0);
  if( elem1->type() > elem2->type() ) {
    hgcalelem = static_cast<const reco::PFBlockElementCluster*>(elem1);
    gsfelem  = static_cast<const reco::PFBlockElementGsfTrack*>(elem2);
  } else {
    hgcalelem = static_cast<const reco::PFBlockElementCluster*>(elem2);
    gsfelem  = static_cast<const reco::PFBlockElementGsfTrack*>(elem1);
  }
  const reco::PFRecTrack& track = gsfelem->GsftrackPF();
  const reco::PFClusterRef& clusterref = hgcalelem->clusterRef();
  const reco::PFTrajectoryPoint& tkAtECAL =
    track.extrapolatedPoint( ECALShowerMax );
  if( tkAtECAL.isValid() ) {
    dist = LinkByRecHit::computeDist( tkAtECAL.positionREP().eta(),
                      tkAtECAL.positionREP().phi(), 
                      clusterref->positionREP().Eta(), 
                      clusterref->positionREP().Phi() );
    if( dist > 0.3 ) dist = -1.0;
  }
  if ( _debug ) {
    if ( dist > 0. ) {
      std::cout << " Here a link has been established" 
        << " between a GSF track an HGCal with dist  " 
        << dist <<  std::endl;
    } else {
      if( _debug ) std::cout << " No link found " << std::endl;
    }
  }
  
  return dist;
}