CMSSW_4_4_3_patch1/src/SimTracker/TrackAssociation/src/TrackAssociatorByHits.cc

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//
//
#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Framework/interface/ESHandle.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "DataFormats/Common/interface/Ref.h"
#include "SimTracker/TrackAssociation/interface/TrackAssociatorByHits.h"
#include "SimTracker/TrackerHitAssociation/interface/TrackerHitAssociator.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "FWCore/Utilities/interface/Exception.h"

//reco track
#include "DataFormats/TrackReco/interface/TrackFwd.h"
#include "DataFormats/TrackReco/interface/Track.h"
#include "DataFormats/TrackingRecHit/interface/TrackingRecHit.h"
//TrackingParticle
#include "SimDataFormats/TrackingAnalysis/interface/TrackingParticle.h"
#include "SimDataFormats/TrackingAnalysis/interface/TrackingParticleFwd.h"
#include "SimDataFormats/EncodedEventId/interface/EncodedEventId.h"
//##---new stuff
#include "Geometry/CommonDetUnit/interface/GeomDetUnit.h"
#include "DataFormats/DetId/interface/DetId.h"
#include "Geometry/TrackerGeometryBuilder/interface/TrackerGeometry.h"
#include "DataFormats/SiStripDetId/interface/StripSubdetector.h"
#include "DataFormats/SiPixelDetId/interface/PixelSubdetector.h"
#include "DataFormats/SiStripDetId/interface/TECDetId.h" 
#include "DataFormats/SiStripDetId/interface/TIBDetId.h" 
#include "DataFormats/SiStripDetId/interface/TIDDetId.h"
#include "DataFormats/SiStripDetId/interface/TOBDetId.h" 
#include "DataFormats/SiPixelDetId/interface/PXBDetId.h"
#include "DataFormats/SiPixelDetId/interface/PXFDetId.h"
using namespace reco;
using namespace std;

/* Constructor */
TrackAssociatorByHits::TrackAssociatorByHits (const edm::ParameterSet& conf) :  
  conf_(conf),
  AbsoluteNumberOfHits(conf_.getParameter<bool>("AbsoluteNumberOfHits")),
  SimToRecoDenominator(denomnone),
  quality_SimToReco(conf_.getParameter<double>("Quality_SimToReco")),
  purity_SimToReco(conf_.getParameter<double>("Purity_SimToReco")),
  cut_RecoToSim(conf_.getParameter<double>("Cut_RecoToSim")),
  UsePixels(conf_.getParameter<bool>("UsePixels")),
  UseGrouped(conf_.getParameter<bool>("UseGrouped")),
  UseSplitting(conf_.getParameter<bool>("UseSplitting")),
  ThreeHitTracksAreSpecial(conf_.getParameter<bool>("ThreeHitTracksAreSpecial"))
{
  std::string tmp = conf_.getParameter<string>("SimToRecoDenominator");
  if (tmp=="sim") {
    SimToRecoDenominator = denomsim;
  } else if (tmp == "reco") {
    SimToRecoDenominator = denomreco;
  } 

  if (SimToRecoDenominator == denomnone) {
    throw cms::Exception("TrackAssociatorByHits") << "SimToRecoDenominator not specified as sim or reco";
  }

}


/* Destructor */
TrackAssociatorByHits::~TrackAssociatorByHits()
{
  //do cleanup here
}

//
//---member functions
//

RecoToSimCollection  
TrackAssociatorByHits::associateRecoToSim(const edm::RefToBaseVector<reco::Track>& tC, 
                                          const edm::RefVector<TrackingParticleCollection>& TPCollectionH,
                                          const edm::Event * e,
                                          const edm::EventSetup *setup ) const{

  //edm::LogVerbatim("TrackAssociator") << "Starting TrackAssociatorByHits::associateRecoToSim - #tracks="<<tC.size()<<" #TPs="<<TPCollectionH.size();
  int nshared = 0;
  float quality=0;//fraction or absolute number of shared hits
  std::vector< SimHitIdpr> SimTrackIds;
  std::vector< SimHitIdpr> matchedIds; 
  RecoToSimCollection  outputCollection;
  
  TrackerHitAssociator * associate = new TrackerHitAssociator(*e, conf_);
  
  TrackingParticleCollection tPC;
  if (TPCollectionH.size()!=0)  tPC = *const_cast<TrackingParticleCollection*>(TPCollectionH.product());

  //get the ID of the recotrack  by hits 
  int tindex=0;
  for (edm::RefToBaseVector<reco::Track>::const_iterator track=tC.begin(); track!=tC.end(); track++, tindex++){
    matchedIds.clear();
    int ri=0;//valid rechits
    //LogTrace("TrackAssociator") << "\nNEW TRACK - track number " << tindex <<" with pt =" << (*track)->pt() << " # valid=" << (*track)->found(); 
    getMatchedIds<trackingRecHit_iterator>(matchedIds, SimTrackIds, ri, (*track)->recHitsBegin(), (*track)->recHitsEnd(), associate);

    //LogTrace("TrackAssociator") << "MATCHED IDS LIST BEGIN" ;
    //for(size_t j=0; j<matchedIds.size(); j++){
    //  LogTrace("TrackAssociator") << "matchedIds[j].first=" << matchedIds[j].first;
    //}
    //LogTrace("TrackAssociator") << "MATCHED IDS LIST END" ;
    //LogTrace("TrackAssociator") << "#matched ids=" << matchedIds.size() << " #tps=" << tPC.size();

    //save id for the track
    std::vector<SimHitIdpr> idcachev;
    if(!matchedIds.empty()){

      int tpindex =0;
      for (TrackingParticleCollection::iterator t = tPC.begin(); t != tPC.end(); ++t, ++tpindex) {
        //int nsimhit = t->trackPSimHit(DetId::Tracker).size(); 
        //LogTrace("TrackAssociator") << "TP number " << tpindex << " pdgId=" << t->pdgId() << " with number of PSimHits: "  << nsimhit;
        idcachev.clear();
        nshared = getShared(matchedIds, idcachev, t);

        //if electron subtract double counting
        if (abs(t->pdgId())==11&&(t->g4Track_end()-t->g4Track_begin())>1){
          nshared-=getDoubleCount<trackingRecHit_iterator>((*track)->recHitsBegin(), (*track)->recHitsEnd(), associate, t);
        }

        if (AbsoluteNumberOfHits) quality = static_cast<double>(nshared);
        else if(ri!=0) quality = (static_cast<double>(nshared)/static_cast<double>(ri));
        else quality = 0;
        //cut on the fraction
        //float purity = 1.0*nshared/ri;
        if(quality > cut_RecoToSim && !(ThreeHitTracksAreSpecial && ri==3 && nshared<3)){
          //if a track has just 3 hits we require that all 3 hits are shared
          outputCollection.insert(tC[tindex],
                                  std::make_pair(edm::Ref<TrackingParticleCollection>(TPCollectionH, tpindex),
                                                 quality));
//          LogTrace("TrackAssociator") << "reco::Track number " << tindex  << " with #hits=" << ri <<" pt=" << (*track)->pt() 
//                                      << " associated to TP (pdgId, nb segments, p) = " 
//                                      << (*t).pdgId() << " " << (*t).g4Tracks().size() 
//                                      << " " << (*t).momentum() << " #hits=" << nsimhit
//                                      << " TP index=" << tpindex<< " with quality =" << quality;
        } else {
//          LogTrace("TrackAssociator") <<"reco::Track number " << tindex << " with #hits=" << ri 
//                                      << " NOT associated with quality =" << quality;
        }
      }//TP loop
    }
  }
  //LogTrace("TrackAssociator") << "% of Assoc Tracks=" << ((double)outputCollection.size())/((double)tC.size());
  delete associate;
  outputCollection.post_insert();
  return outputCollection;
}


SimToRecoCollection  
TrackAssociatorByHits::associateSimToReco(const edm::RefToBaseVector<reco::Track>& tC, 
                                          const edm::RefVector<TrackingParticleCollection>& TPCollectionH,
                                          const edm::Event * e,
                                          const edm::EventSetup *setup ) const{
//  edm::LogVerbatim("TrackAssociator") << "Starting TrackAssociatorByHits::associateSimToReco - #tracks="<<tC.size()<<" #TPs="<<TPCollectionH.size();
  float quality=0;//fraction or absolute number of shared hits
  int nshared = 0;
  std::vector< SimHitIdpr> SimTrackIds;
  std::vector< SimHitIdpr> matchedIds; 
  SimToRecoCollection  outputCollection;

  TrackerHitAssociator * associate = new TrackerHitAssociator(*e, conf_);
  
  TrackingParticleCollection tPC;
  if (TPCollectionH.size()!=0)  tPC = *const_cast<TrackingParticleCollection*>(TPCollectionH.product());

  //for (TrackingParticleCollection::const_iterator t = tPC.begin(); t != tPC.end(); ++t) {
  //  LogTrace("TrackAssociator") << "NEW TP DUMP";
  //  for (TrackingParticle::g4t_iterator g4T = t -> g4Track_begin();g4T !=  t -> g4Track_end(); ++g4T) {
  //    LogTrace("TrackAssociator") << "(*g4T).trackId()=" <<(*g4T).trackId() ;
  //  }
  //}
  
  //get the ID of the recotrack  by hits 
  int tindex=0;
  for (edm::RefToBaseVector<reco::Track>::const_iterator track=tC.begin(); track!=tC.end(); track++, tindex++){
    //LogTrace("TrackAssociator") << "\nNEW TRACK - hits of track number " << tindex <<" with pt =" << (*track)->pt() << " # valid=" << (*track)->found(); 
    int ri=0;//valid rechits
    getMatchedIds<trackingRecHit_iterator>(matchedIds, SimTrackIds, ri, (*track)->recHitsBegin(), (*track)->recHitsEnd(), associate);

    //save id for the track
    std::vector<SimHitIdpr> idcachev;
    if(!matchedIds.empty()){
        
      int tpindex =0;
      for (TrackingParticleCollection::iterator t = tPC.begin(); t != tPC.end(); ++t, ++tpindex) {
        idcachev.clear();
        std::vector<PSimHit> trackerPSimHit( t->trackPSimHit(DetId::Tracker) );
        //int nsimhit = trackerPSimHit.size();
        float totsimhit = 0; 
        std::vector<PSimHit> tphits;
        //LogTrace("TrackAssociator") << "TP number " << tpindex << " pdgId=" << t->pdgId() << " with number of PSimHits: "  << nsimhit;

        nshared = getShared(matchedIds, idcachev, t);

        //for(std::vector<PSimHit>::const_iterator TPhit = t->trackerPSimHit_begin(); TPhit != t->trackerPSimHit_end(); TPhit++){
        //  unsigned int detid = TPhit->detUnitId();
        //  DetId detId = DetId(TPhit->detUnitId());
        //  LogTrace("TrackAssociator") <<  " hit trackId= " << TPhit->trackId() << " det ID = " << detid 
        //                                    << " SUBDET = " << detId.subdetId() << " layer = " << LayerFromDetid(detId); 
        //}

        if (nshared!=0) {//do not waste time recounting when it is not needed!!!!

          //count the TP simhit
          //LogTrace("TrackAssociator") << "recounting of tp hits";
          for(std::vector<PSimHit>::const_iterator TPhit = trackerPSimHit.begin(); TPhit != trackerPSimHit.end(); TPhit++){
            DetId dId = DetId(TPhit->detUnitId());
          
            unsigned int subdetId = static_cast<unsigned int>(dId.subdetId());
            if (!UsePixels && (subdetId==PixelSubdetector::PixelBarrel || subdetId==PixelSubdetector::PixelEndcap) )
              continue;

            //unsigned int dRawId = dId.rawId();
            SiStripDetId* stripDetId = 0;
            if (subdetId==SiStripDetId::TIB||subdetId==SiStripDetId::TOB||
                subdetId==SiStripDetId::TID||subdetId==SiStripDetId::TEC)
              stripDetId= new SiStripDetId(dId);
            //LogTrace("TrackAssociator") << "consider hit SUBDET = " << subdetId
            //                            << " layer = " << LayerFromDetid(dId) 
            //                            << " id = " << dId.rawId();
            bool newhit = true;
            for(std::vector<PSimHit>::const_iterator TPhitOK = tphits.begin(); TPhitOK != tphits.end(); TPhitOK++){
              DetId dIdOK = DetId(TPhitOK->detUnitId());
              //unsigned int dRawIdOK = dIdOK.rawId();
              //LogTrace("TrackAssociator") << "\t\tcompare with SUBDET = " << dIdOK.subdetId()
              //                            << " layer = " << LayerFromDetid(dIdOK)
              //                            << " id = " << dIdOK.rawId();
              //no grouped, no splitting
              if (!UseGrouped && !UseSplitting)
                if (LayerFromDetid(dId)==LayerFromDetid(dIdOK) &&
                    dId.subdetId()==dIdOK.subdetId()) newhit = false;
              //no grouped, splitting
              if (!UseGrouped && UseSplitting)
                if (LayerFromDetid(dId)==LayerFromDetid(dIdOK) &&
                    dId.subdetId()==dIdOK.subdetId() &&
                    (stripDetId==0 || stripDetId->partnerDetId()!=dIdOK.rawId()))
                  newhit = false;
              //grouped, no splitting
              if (UseGrouped && !UseSplitting)
                if (LayerFromDetid(dId)==LayerFromDetid(dIdOK) &&
                    dId.subdetId()==dIdOK.subdetId() &&
                    stripDetId!=0 && stripDetId->partnerDetId()==dIdOK.rawId())
                  newhit = false;
              //grouped, splitting
              if (UseGrouped && UseSplitting)
                newhit = true;
            }
            if (newhit) {
              //LogTrace("TrackAssociator") << "\t\tok";
              tphits.push_back(*TPhit);
            }
            //else LogTrace("TrackAssociator") << "\t\tno";
            delete stripDetId;
          }
          totsimhit = tphits.size();
        }

        if (AbsoluteNumberOfHits) quality = static_cast<double>(nshared);
        else if(SimToRecoDenominator == denomsim && totsimhit!=0) quality = ((double) nshared)/((double)totsimhit);
        else if(SimToRecoDenominator == denomreco && ri!=0) quality = ((double) nshared)/((double)ri);
        else quality = 0;
        //LogTrace("TrackAssociator") << "Final count: nhit(TP) = " << nsimhit << " re-counted = " << totsimhit 
        //<< " nshared = " << nshared << " nrechit = " << ri;
        
        float purity = 1.0*nshared/ri;
        if (quality>quality_SimToReco && !(ThreeHitTracksAreSpecial && totsimhit==3 && nshared<3) && (AbsoluteNumberOfHits||(purity>purity_SimToReco))) {
          //if a track has just 3 hits we require that all 3 hits are shared
          outputCollection.insert(edm::Ref<TrackingParticleCollection>(TPCollectionH, tpindex), 
                                  std::make_pair(tC[tindex],quality));
//          LogTrace("TrackAssociator") << "TrackingParticle number " << tpindex << " with #hits=" << nsimhit 
//                                      << " re-counted = "  << totsimhit << " nshared = " << nshared 
//                                      << " associated to track number " << tindex << " with pt=" << (*track)->pt() 
//                                      << " with hit quality =" << quality ;
        } else {
//          LogTrace("TrackAssociator") << "TrackingParticle number " << tpindex << " with #hits=" << nsimhit 
//                                      << " re-counted = "  << totsimhit << " nshared = " << nshared 
//                                      << " NOT associated with quality =" << quality;
        }
      }
    }
  }
  //LogTrace("TrackAssociator") << "% of Assoc TPs=" << ((double)outputCollection.size())/((double)TPCollectionH.size());
  delete associate;
  outputCollection.post_insert();
  return outputCollection;
}

int TrackAssociatorByHits::LayerFromDetid(const DetId& detId ) const
{
  int layerNumber=0;
  unsigned int subdetId = static_cast<unsigned int>(detId.subdetId()); 
  if ( subdetId == StripSubdetector::TIB) 
    { 
      TIBDetId tibid(detId.rawId()); 
      layerNumber = tibid.layer();
    }
  else if ( subdetId ==  StripSubdetector::TOB )
    { 
      TOBDetId tobid(detId.rawId()); 
      layerNumber = tobid.layer();
    }
  else if ( subdetId ==  StripSubdetector::TID) 
    { 
      TIDDetId tidid(detId.rawId());
      layerNumber = tidid.wheel();
    }
  else if ( subdetId ==  StripSubdetector::TEC )
    { 
      TECDetId tecid(detId.rawId()); 
      layerNumber = tecid.wheel(); 
    }
  else if ( subdetId ==  PixelSubdetector::PixelBarrel ) 
    { 
      PXBDetId pxbid(detId.rawId()); 
      layerNumber = pxbid.layer();  
    }
  else if ( subdetId ==  PixelSubdetector::PixelEndcap ) 
    { 
      PXFDetId pxfid(detId.rawId()); 
      layerNumber = pxfid.disk();  
    }
  else
    LogTrace("TrackAssociator") << "Unknown subdetid: " <<  subdetId;
  
  return layerNumber;
} 

RecoToSimCollectionSeed  
TrackAssociatorByHits::associateRecoToSim(edm::Handle<edm::View<TrajectorySeed> >& seedCollectionH,
                                          edm::Handle<TrackingParticleCollection>&  TPCollectionH,     
                                          const edm::Event * e,
                                          const edm::EventSetup *setup ) const{

  edm::LogVerbatim("TrackAssociator") << "Starting TrackAssociatorByHits::associateRecoToSim - #seeds="
                                      <<seedCollectionH->size()<<" #TPs="<<TPCollectionH->size();
  int nshared = 0;
  float quality=0;//fraction or absolute number of shared hits
  std::vector< SimHitIdpr> SimTrackIds;
  std::vector< SimHitIdpr> matchedIds; 
  RecoToSimCollectionSeed  outputCollection;
  
  TrackerHitAssociator * associate = new TrackerHitAssociator(*e, conf_);
  
  const TrackingParticleCollection tPC   = *(TPCollectionH.product());

  const edm::View<TrajectorySeed> sC = *(seedCollectionH.product()); 
  
  //get the ID of the recotrack  by hits 
  int tindex=0;
  for (edm::View<TrajectorySeed>::const_iterator seed=sC.begin(); seed!=sC.end(); seed++, tindex++) {
    matchedIds.clear();
    int ri=0;//valid rechits
    int nsimhit = seed->recHits().second-seed->recHits().first;
    LogTrace("TrackAssociator") << "\nNEW SEED - seed number " << tindex << " # valid=" << nsimhit;
    getMatchedIds<edm::OwnVector<TrackingRecHit>::const_iterator>(matchedIds, SimTrackIds, ri, seed->recHits().first, seed->recHits().second, associate );

    //save id for the track
    std::vector<SimHitIdpr> idcachev;
    if(!matchedIds.empty()){

      int tpindex =0;
      for (TrackingParticleCollection::const_iterator t = tPC.begin(); t != tPC.end(); ++t, ++tpindex) {
        LogTrace("TrackAssociator") << "TP number " << tpindex << " pdgId=" << t->pdgId() << " with number of PSimHits: "  << nsimhit;
        idcachev.clear();
        nshared = getShared(matchedIds, idcachev, t);

        //if electron subtract double counting
        if (abs(t->pdgId())==11&&(t->g4Track_end()-t->g4Track_begin())>1){
          nshared-=getDoubleCount<edm::OwnVector<TrackingRecHit>::const_iterator>(seed->recHits().first, seed->recHits().second, associate, t);
        }
        
        if (AbsoluteNumberOfHits) quality = static_cast<double>(nshared);
        else if(ri!=0) quality = (static_cast<double>(nshared)/static_cast<double>(ri));
        else quality = 0;
        //cut on the fraction
        if(quality > cut_RecoToSim && !(ThreeHitTracksAreSpecial && ri==3 && nshared<3) ){
          //if a track has just 3 hits we require that all 3 hits are shared
          outputCollection.insert(edm::RefToBase<TrajectorySeed>(seedCollectionH,tindex), 
                                  std::make_pair(edm::Ref<TrackingParticleCollection>(TPCollectionH, tpindex),quality));
          LogTrace("TrackAssociator") << "Seed number " << tindex << " with #hits=" << ri
                                      << "associated to TP (pdgId, nb segments, p) = " 
                                      << (*t).pdgId() << " " << (*t).g4Tracks().size() 
                                      << " " << (*t).momentum() <<" number " << tpindex << " with quality =" << quality;
        } else {
          LogTrace("TrackAssociator") <<"Seed number " << tindex << " with #hits=" << ri << " NOT associated with quality =" << quality;
        }
      }//TP loop
    }
  }
  LogTrace("TrackAssociator") << "% of Assoc Seeds=" << ((double)outputCollection.size())/((double)seedCollectionH->size());
  delete associate;
  outputCollection.post_insert();
  return outputCollection;
}


SimToRecoCollectionSeed
TrackAssociatorByHits::associateSimToReco(edm::Handle<edm::View<TrajectorySeed> >& seedCollectionH,
                                          edm::Handle<TrackingParticleCollection>& TPCollectionH, 
                                          const edm::Event * e,
                                          const edm::EventSetup *setup ) const{

  edm::LogVerbatim("TrackAssociator") << "Starting TrackAssociatorByHits::associateSimToReco - #seeds="
                                      <<seedCollectionH->size()<<" #TPs="<<TPCollectionH->size();
  float quality=0;//fraction or absolute number of shared hits
  int nshared = 0;
  std::vector< SimHitIdpr> SimTrackIds;
  std::vector< SimHitIdpr> matchedIds; 
  SimToRecoCollectionSeed  outputCollection;

  TrackerHitAssociator * associate = new TrackerHitAssociator(*e, conf_);
  
  TrackingParticleCollection tPC =*const_cast<TrackingParticleCollection*>(TPCollectionH.product());

  const edm::View<TrajectorySeed> sC = *(seedCollectionH.product()); 

  //get the ID of the recotrack  by hits 
  int tindex=0;
  for (edm::View<TrajectorySeed>::const_iterator seed=sC.begin(); seed!=sC.end(); seed++, tindex++) {
    int ri=0;//valid rechits
    LogTrace("TrackAssociator") << "\nNEW SEED - seed number " << tindex << " # valid=" << seed->recHits().second-seed->recHits().first;
    getMatchedIds<edm::OwnVector<TrackingRecHit>::const_iterator>(matchedIds, SimTrackIds, ri, seed->recHits().first, seed->recHits().second, associate );

    //save id for the track
    std::vector<SimHitIdpr> idcachev;
    if(!matchedIds.empty()){
      int tpindex =0;
      for (TrackingParticleCollection::iterator t = tPC.begin(); t != tPC.end(); ++t, ++tpindex) {
        idcachev.clear();
        int nsimhit = t->trackPSimHit(DetId::Tracker).size(); 
        LogTrace("TrackAssociator") << "TP number " << tpindex << " pdgId=" << t->pdgId() << " with number of PSimHits: "  << nsimhit;
        nshared = getShared(matchedIds, idcachev, t);
        
        if (AbsoluteNumberOfHits) quality = static_cast<double>(nshared);
        else if(ri!=0) quality = ((double) nshared)/((double)ri);
        else quality = 0;
        //LogTrace("TrackAssociator") << "Final count: nhit(TP) = " << nsimhit 
        //<< " nshared = " << nshared 
        //<< " nrechit = " << ri;
        if(quality > quality_SimToReco && !(ThreeHitTracksAreSpecial && ri==3 && nshared<3) ){
          outputCollection.insert(edm::Ref<TrackingParticleCollection>(TPCollectionH, tpindex), 
                                  std::make_pair(edm::RefToBase<TrajectorySeed>(seedCollectionH,tindex), quality));
          LogTrace("TrackAssociator") << "TrackingParticle number " << tpindex << " with #hits=" << nsimhit
                                      << " associated to seed number " << tindex << " with #hits=" << ri 
                                      << " with hit quality =" << quality ;
        }
        else {
          LogTrace("TrackAssociator") << "TrackingParticle number " << tpindex << " with #hits=" << nsimhit << " NOT associated with quality =" << quality;
        }
      }
    }
  }
  LogTrace("TrackAssociator") << "% of Assoc TPs=" << ((double)outputCollection.size())/((double)TPCollectionH->size());
  delete associate;
  outputCollection.post_insert();
  return outputCollection;
}

template<typename iter>
void TrackAssociatorByHits::getMatchedIds(std::vector<SimHitIdpr>& matchedIds, 
                                          std::vector<SimHitIdpr>& SimTrackIds, 
                                          int& ri, 
                                          iter begin,
                                          iter end,
                                          TrackerHitAssociator* associate ) const {
    matchedIds.clear();
    ri=0;//valid rechits
    for (iter it = begin;  it != end; it++){
      const TrackingRecHit *hit=getHitPtr(it);
      if (hit->isValid()){
        ri++;
        uint32_t t_detID=  hit->geographicalId().rawId();
        SimTrackIds.clear();      
        associate->associateHitId(*hit, SimTrackIds);
        //save all the id of matched simtracks
        if(!SimTrackIds.empty()){
         for(size_t j=0; j<SimTrackIds.size(); j++){
           LogTrace("TrackAssociator") << " hit # " << ri << " valid=" << hit->isValid() 
                                       << " det id = " << t_detID << " SimId " << SimTrackIds[j].first 
                                       << " evt=" << SimTrackIds[j].second.event() 
                                       << " bc=" << SimTrackIds[j].second.bunchCrossing();  
           matchedIds.push_back(SimTrackIds[j]);                        
         }
        }
        //****to be used when the crossing frame is in the event and with flag TrackAssociatorByHitsESProducer.associateRecoTracks = false
        //std::vector<PSimHit> tmpSimHits = associate->associateHit(*getHitPtr(it));
        //for(size_t j=0; j<tmpSimHits.size(); j++) {
        //  LogTrace("TrackAssociator") << " hit # " << ri << " valid=" << getHitPtr(it)->isValid()
        //                              << " det id = " << t_detID << " SimId " << SimTrackIds[j].first
        //                              << " evt=" << SimTrackIds[j].second.event()
        //                              << " bc=" << SimTrackIds[j].second.bunchCrossing()
        //                              << " process=" << tmpSimHits[j].processType()
        //                              << " eloss=" << tmpSimHits[j].energyLoss()
        //                              << " part type=" << tmpSimHits[j].particleType()
        //                              << " pabs=" << tmpSimHits[j].pabs()
        //                              << " trId=" << tmpSimHits[j].trackId();
        //}
      }else{
        LogTrace("TrackAssociator") <<"\t\t Invalid Hit On "<<hit->geographicalId().rawId();
      }
    }//trackingRecHit loop
}


int TrackAssociatorByHits::getShared(std::vector<SimHitIdpr>& matchedIds, 
                                     std::vector<SimHitIdpr>& idcachev,
                                     TrackingParticleCollection::const_iterator t) const {
  int nshared = 0;
  if (t->trackPSimHit().size()==0) return nshared;//should use trackerPSimHit but is not const

  for(size_t j=0; j<matchedIds.size(); j++){
    //LogTrace("TrackAssociator") << "now matchedId=" << matchedIds[j].first;
    if(find(idcachev.begin(), idcachev.end(),matchedIds[j]) == idcachev.end() ){
      //only the first time we see this ID 
      idcachev.push_back(matchedIds[j]);
      
      for (TrackingParticle::g4t_iterator g4T = t -> g4Track_begin(); g4T !=  t -> g4Track_end(); ++g4T) {
//      LogTrace("TrackAssociator") << " TP   (ID, Ev, BC) = " << (*g4T).trackId() 
//                                  << ", " << t->eventId().event() << ", "<< t->eventId().bunchCrossing()
//                                  << " Match(ID, Ev, BC) = " <<  matchedIds[j].first
//                                  << ", " << matchedIds[j].second.event() << ", "
//                                  << matchedIds[j].second.bunchCrossing() ;
                                    //<< "\t G4  Track Momentum " << (*g4T).momentum() 
                                    //<< " \t reco Track Momentum " << track->momentum();             
        if((*g4T).trackId() == matchedIds[j].first && t->eventId() == matchedIds[j].second){
                int countedhits = std::count(matchedIds.begin(), matchedIds.end(), matchedIds[j]);
                nshared += countedhits;

//              LogTrace("TrackAssociator") << "hits shared by this segment : " << countedhits;
//              LogTrace("TrackAssociator") << "hits shared so far : " << nshared;
        }
      }//g4Tracks loop
    }
  }
  return nshared;
}


template<typename iter>
int TrackAssociatorByHits::getDoubleCount(iter begin,
                                          iter end,
                                          TrackerHitAssociator* associate,
                                          TrackingParticleCollection::const_iterator t) const {
  int doublecount = 0 ;
  std::vector<SimHitIdpr> SimTrackIdsDC;
  //  cout<<begin-end<<endl;
  for (iter it = begin;  it != end; it++){
    int idcount = 0;
    SimTrackIdsDC.clear();
    associate->associateHitId(*getHitPtr(it), SimTrackIdsDC);
    //    cout<<SimTrackIdsDC.size()<<endl;
    if(SimTrackIdsDC.size()>1){
      //     cout<<(t->g4Track_end()-t->g4Track_begin())<<endl;
      for (TrackingParticle::g4t_iterator g4T = t -> g4Track_begin(); g4T !=  t -> g4Track_end(); ++g4T) {
        if(find(SimTrackIdsDC.begin(), SimTrackIdsDC.end(),SimHitIdpr((*g4T).trackId(), SimTrackIdsDC.begin()->second)) != SimTrackIdsDC.end() ){
          idcount++;
        }
      }
    }
    if (idcount>1) doublecount+=(idcount-1);
  }
  return doublecount;
}