#include <JetMatchingTools.h>

Classes
struct	JetConstituent

Public Member Functions
int	generatorId (unsigned fSimTrackId)
	Generator ID. More...

std::vector< const CaloTower * >	getCaloTowers (int fGeneratorId)
	CaloTowers. More...

std::vector< JetConstituent >	getConstituentHits (const CaloTower &fTower)
	get CaloRecHits contributing to the tower More...

std::vector< DetId >	getConstituentIds (const CaloTower &fTower)
	get cells contributing to the tower More...

std::vector< const CaloTower * >	getConstituents (const reco::CaloJet &fJet)
	get towers contributing to CaloJet More...

const EBRecHitCollection *	getEBRecHitCollection ()

const edm::PCaloHitContainer *	getEBSimHitCollection ()

const EERecHitCollection *	getEERecHitCollection ()

const edm::PCaloHitContainer *	getEESimHitCollection ()

const reco::GenParticle *	getGenParticle (int fGeneratorId)
	GenParticle. More...

std::vector< const reco::GenParticle * >	getGenParticles (const reco::CaloJet &fJet, bool fVerbose=true)
	GenParticles for CaloJet. More...

std::vector< const reco::GenParticle * >	getGenParticles (const reco::GenJet &fJet)
	GenParticles for GenJet. More...

const reco::CandidateCollection *	getGenParticlesCollection ()

const HBHERecHitCollection *	getHBHERecHitCollection ()

const edm::PCaloHitContainer *	getHcalSimHitCollection ()

const HFRecHitCollection *	getHFRecHitCollection ()

const HORecHitCollection *	getHORecHitCollection ()

std::vector< const PCaloHit * >	getPCaloHits (DetId fId)
	get PCaloHits contributing to the detId More...

std::vector< const PCaloHit * >	getPCaloHits (int fGeneratorId)
	CaloSimHits. More...

const edm::SimTrackContainer *	getSimTrackCollection ()

const edm::SimVertexContainer *	getSimVertexCollection ()

const SimTrack *	getTrack (unsigned fSimTrackId)
	convert trackId to SimTrack More...

int	getTrackId (const PCaloHit &fHit)
	GEANT track ID. More...

	JetMatchingTools (const edm::Event &fEvent, edm::ConsumesCollector &&iC)

double	lostEnergyFraction (const reco::CaloJet &fJet)
	energy in broken links More...

double	overlapEnergyFraction (const std::vector< const reco::GenParticle * > &fObject, const std::vector< const reco::GenParticle * > &fReference) const
	energy overlap More...

	~JetMatchingTools ()

Private Attributes
edm::EDGetTokenT < reco::CandidateCollection >	input_cands_token_

edm::EDGetTokenT < EBRecHitCollection >	input_ebrechits_token_

edm::EDGetTokenT < EERecHitCollection >	input_eerechits_token_

edm::EDGetTokenT < HBHERecHitCollection >	input_hbherechits_token_

edm::EDGetTokenT < HFRecHitCollection >	input_hfrechits_token_

edm::EDGetTokenT < HORecHitCollection >	input_horechits_token_

edm::EDGetTokenT < edm::PCaloHitContainer >	input_pcalohits_ebcal_token_

edm::EDGetTokenT < edm::PCaloHitContainer >	input_pcalohits_eecal_token_

edm::EDGetTokenT < edm::PCaloHitContainer >	input_pcalohits_hcal_token_

edm::EDGetTokenT < edm::SimTrackContainer >	input_simtrack_token_

edm::EDGetTokenT < edm::SimVertexContainer >	input_simvertex_token_

const EBRecHitCollection *	mEBRecHitCollection

const edm::PCaloHitContainer *	mEBSimHitCollection

const EERecHitCollection *	mEERecHitCollection

const edm::PCaloHitContainer *	mEESimHitCollection

const edm::Event *	mEvent

const reco::CandidateCollection *	mGenParticleCollection

const HBHERecHitCollection *	mHBHERecHitCollection

const edm::PCaloHitContainer *	mHcalSimHitCollection

const HFRecHitCollection *	mHFRecHitCollection

const HORecHitCollection *	mHORecHitCollection

const edm::SimTrackContainer *	mSimTrackCollection

const edm::SimVertexContainer *	mSimVertexCollection

Detailed Description

Definition at line 28 of file JetMatchingTools.h.

Constructor & Destructor Documentation

JetMatchingTools::JetMatchingTools	(	const edm::Event &	fEvent,
		edm::ConsumesCollector &&	iC
	)

Definition at line 36 of file JetMatchingTools.cc.

References input_cands_token_, input_ebrechits_token_, input_eerechits_token_, input_hbherechits_token_, input_hfrechits_token_, input_horechits_token_, input_pcalohits_ebcal_token_, input_pcalohits_eecal_token_, input_pcalohits_hcal_token_, input_simtrack_token_, input_simvertex_token_, and HLT_25ns14e33_v1_cff::InputTag.

   : mEvent (&fEvent),
     mEBRecHitCollection (0),
     mEERecHitCollection (0),
     mHBHERecHitCollection (0),
     mHORecHitCollection (0),
     mHFRecHitCollection (0),
     mEBSimHitCollection (0),
     mEESimHitCollection (0),
     mHcalSimHitCollection (0),
     mSimTrackCollection (0),
     mSimVertexCollection (0),
     mGenParticleCollection (0)
 {
 
   input_ebrechits_token_ =   iC.mayConsume<EBRecHitCollection>(edm::InputTag ("ecalRecHit:EcalRecHitsEB")); 
   input_eerechits_token_ =   iC.mayConsume<EERecHitCollection>(edm::InputTag ("ecalRecHit:EcalRecHitsEE"));       
   input_hbherechits_token_ =     iC.mayConsume<HBHERecHitCollection>(edm::InputTag ("hbhereco"));     
   input_horechits_token_ =   iC.mayConsume<HORecHitCollection>(edm::InputTag ("horeco"));       
   input_hfrechits_token_ =   iC.mayConsume<HFRecHitCollection>(edm::InputTag ("hfreco"));       
   input_pcalohits_ebcal_token_ =  iC.mayConsume<edm::PCaloHitContainer>(edm::InputTag ("g4SimHits:EcalHitsEB"));  
   input_pcalohits_eecal_token_ =  iC.mayConsume<edm::PCaloHitContainer>(edm::InputTag ("g4SimHits:EcalHitsEE"));    
   input_pcalohits_hcal_token_ =  iC.mayConsume<edm::PCaloHitContainer>(edm::InputTag ("g4SimHits:HcalHits"));
   input_simtrack_token_ =    iC.mayConsume<edm::SimTrackContainer>(edm::InputTag ("g4SimHits"));   
   input_simvertex_token_ =   iC.mayConsume<edm::SimVertexContainer>(edm::InputTag ("g4SimHits"));  
   input_cands_token_ =           iC.mayConsume<reco::CandidateCollection>(edm::InputTag ("genParticleCandidates"));
 
 }

JetMatchingTools::~JetMatchingTools ( )

Definition at line 65 of file JetMatchingTools.cc.

65 {}

Member Function Documentation

int JetMatchingTools::generatorId ( unsigned fSimTrackId )

Generator ID.

Definition at line 242 of file JetMatchingTools.cc.

References ecal_dqm_sourceclient-live_cfg::cerr, SimTrack::genpartIndex(), getSimVertexCollection(), getTrack(), SimTrack::noGenpart(), SimVertex::noParent(), SimTrack::noVertex(), SimVertex::parentIndex(), and SimTrack::vertIndex().

Referenced by getGenParticles(), and lostEnergyFraction().

                                                        {
   const SimTrack* track = getTrack (fSimTrackId);
   if (!track) return -1;
   while (track->noGenpart ()) {
     if (track->noVertex ()) {
       std::cerr << "JetMatchingTools::generatorId-> No vertex for track " << *track << std::endl;
       return -1;
     }
     const SimVertex* vertex = &((*getSimVertexCollection ())[track->vertIndex ()]);
     if (vertex->noParent()) {
       std::cerr << "JetMatchingTools::generatorId-> No track for vertex " << *vertex << std::endl;
       return -1;
     }
     track = getTrack (vertex->parentIndex ());
   }
   return track->genpartIndex ();
 }

std::vector<const CaloTower*> JetMatchingTools::getCaloTowers ( int fGeneratorId )

CaloTowers.

std::vector< JetMatchingTools::JetConstituent > JetMatchingTools::getConstituentHits ( const CaloTower & fTower )

get CaloRecHits contributing to the tower

Definition at line 165 of file JetMatchingTools.cc.

References assert(), ecal_dqm_sourceclient-live_cfg::cerr, CaloTower::constituent(), CaloTower::constituentsSize(), DetId::Ecal, EcalBarrel, EcalEndcap, getEBRecHitCollection(), getEERecHitCollection(), getHBHERecHitCollection(), getHFRecHitCollection(), getHORecHitCollection(), DetId::Hcal, HcalBarrel, HcalEndcap, HcalForward, HcalOuter, i, NULL, and query::result.

Referenced by lostEnergyFraction().

                                                                                                        {
   std::vector<JetConstituent> result;
 
   for (unsigned i = 0; i < fTower.constituentsSize(); ++i) {
     DetId id = fTower.constituent (i);
 
     if (id.det () == DetId::Ecal) {
       const EcalRecHit *hit = NULL;
 
       if ((EcalSubdetector) id.subdetId () == EcalBarrel) {
         hit = getHit (*getEBRecHitCollection (), id);
       } 
       else if ((EcalSubdetector) id.subdetId () == EcalEndcap) {
         hit = getHit (*getEERecHitCollection (), id);
       }
 
       assert(hit != NULL);
       if (hit) result.push_back(JetConstituent(*hit));
       else std::cerr << "Can not find rechit for id " << id.rawId () << std::endl;
     } else if (id.det () == DetId::Hcal) {
       const CaloRecHit* hit = NULL;
 
       if ((HcalSubdetector) id.subdetId () == HcalBarrel || (HcalSubdetector) id.subdetId () == HcalEndcap) {
         hit = getHit (*getHBHERecHitCollection (), id);
       }
       else if ((HcalSubdetector) id.subdetId () == HcalOuter) {
         hit = getHit (*getHORecHitCollection (), id);
       }
       if ((HcalSubdetector) id.subdetId () == HcalForward) {
         hit = getHit (*getHFRecHitCollection (), id);
       }
 
       if (hit) result.push_back(JetConstituent(*hit));
       else std::cerr << "Can not find rechit for id " << id.rawId () << std::endl;
     }
   }
 
   return result;
 }

std::vector< DetId > JetMatchingTools::getConstituentIds ( const CaloTower & fTower )

get cells contributing to the tower

Definition at line 206 of file JetMatchingTools.cc.

References CaloTower::constituent(), CaloTower::constituentsSize(), i, and query::result.

Referenced by getGenParticles().

                                                                               {
   std::vector <DetId> result;
   for (unsigned i = 0; i < fTower.constituentsSize(); ++i) {
     DetId id = fTower.constituent (i);
     result.push_back (id);
   }
   return result;
 }

std::vector< const CaloTower * > JetMatchingTools::getConstituents ( const reco::CaloJet & fJet )

get towers contributing to CaloJet

Definition at line 157 of file JetMatchingTools.cc.

References reco::CaloJet::getCaloConstituents(), i, and query::result.

Referenced by getGenParticles(), and lostEnergyFraction().

                                                                                         {
   std::vector <const CaloTower*> result;
   std::vector<CaloTowerPtr> constituents = fJet.getCaloConstituents ();
   for (unsigned i = 0; i < constituents.size(); ++i) result.push_back (&*(constituents[i]));
   return result;
 }

const EBRecHitCollection * JetMatchingTools::getEBRecHitCollection ( )

Definition at line 67 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_ebrechits_token_, mEBRecHitCollection, mEvent, and HLT_25ns14e33_v3_cff::recHits.

Referenced by getConstituentHits().

                                                                    {
   if (!mEBRecHitCollection) {
     edm::Handle<EBRecHitCollection> recHits;
     mEvent->getByToken (input_ebrechits_token_, recHits);
     mEBRecHitCollection = &*recHits;
   }
   return mEBRecHitCollection;
 }

const PCaloHitContainer * JetMatchingTools::getEBSimHitCollection ( )

Definition at line 107 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_pcalohits_ebcal_token_, mEBSimHitCollection, mEvent, and trackerHits::simHits.

Referenced by getPCaloHits().

                                                                   {
   if (!mEBSimHitCollection) {
     edm::Handle<PCaloHitContainer> simHits;
     mEvent->getByToken (input_pcalohits_ebcal_token_, simHits);
     mEBSimHitCollection = &*simHits;
   }
   return mEBSimHitCollection;
 }

const EERecHitCollection * JetMatchingTools::getEERecHitCollection ( )

Definition at line 75 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_eerechits_token_, mEERecHitCollection, mEvent, and HLT_25ns14e33_v3_cff::recHits.

Referenced by getConstituentHits().

                                                                    {
   if (!mEERecHitCollection) {
     edm::Handle<EERecHitCollection> recHits;
     mEvent->getByToken (input_eerechits_token_, recHits);
     mEERecHitCollection = &*recHits;
   }
   return mEERecHitCollection;
 }

const PCaloHitContainer * JetMatchingTools::getEESimHitCollection ( )

Definition at line 115 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_pcalohits_eecal_token_, mEESimHitCollection, mEvent, and trackerHits::simHits.

Referenced by getPCaloHits().

                                                                   {
   if (!mEESimHitCollection) {
     edm::Handle<PCaloHitContainer> simHits;
     mEvent->getByToken (input_pcalohits_eecal_token_, simHits);
     mEESimHitCollection = &*simHits;
   }
   return mEESimHitCollection;
 }

const reco::GenParticle * JetMatchingTools::getGenParticle ( int fGeneratorId )

GenParticle.

Definition at line 261 of file JetMatchingTools.cc.

References ecal_dqm_sourceclient-live_cfg::cerr, reco::GenJet::genParticle(), getGenParticlesCollection(), edm::OwnVector< T, P >::size(), and findQualityFiles::size.

Referenced by getGenParticles().

                                                                          {
   if (fGeneratorId > int (getGenParticlesCollection ()->size())) {
     std::cerr << "JetMatchingTools::getGenParticle-> requested index " << fGeneratorId << " is grater then container size " << getGenParticlesCollection ()->size() << std::endl;
     return 0;
   }
   return reco::GenJet::genParticle ( &(*getGenParticlesCollection ())[fGeneratorId-1]); // knowhow: index is shifted by 1
 }

std::vector< const reco::GenParticle * > JetMatchingTools::getGenParticles	(	const reco::CaloJet &	fJet,
		bool	fVerbose = `true`
	)

GenParticles for CaloJet.

Definition at line 270 of file JetMatchingTools.cc.

References ecal_dqm_sourceclient-live_cfg::cerr, generatorId(), getConstituentIds(), getConstituents(), getGenParticle(), getPCaloHits(), getTrackId(), query::result, and HLT_25ns14e33_v1_cff::towers.

Referenced by IsolatedParticlesGeneratedJets::analyze().

                                                                                                             {
   std::set <const reco::GenParticle*> result;
   // follow the chain
   std::vector <const CaloTower*> towers = getConstituents (fJet) ;
   for (unsigned itower = 0; itower < towers.size (); ++itower) {
     std::vector <DetId> detids = getConstituentIds (*(towers[itower])) ;
     for (unsigned iid = 0; iid < detids.size(); ++iid) {
       std::vector <const PCaloHit*> phits = getPCaloHits (detids[iid]);
       for (unsigned iphit = 0; iphit < phits.size(); ++iphit) {
         int trackId = getTrackId (*(phits[iphit]));
         if (trackId >= 0) {
           int genId = generatorId (trackId);
           if (genId >= 0) {
             const reco::GenParticle* genPart = getGenParticle (genId);
             if (genPart) {
               result.insert (genPart);
             }
             else if (fVerbose) {
               std::cerr << "JetMatchingTools::getGenParticles-> Can not convert genId " << genId << " to GenParticle" << std::endl;
             }
           }
           else if (fVerbose) {
             std::cerr << "JetMatchingTools::getGenParticles-> Can not convert trackId " << trackId << " to genId" << std::endl;
           }
         }
         else if (fVerbose) {
           std::cerr << "JetMatchingTools::getGenParticles-> Unknown trackId for PCaloHit " << *(phits[iphit]) << std::endl;
         }
       }
     }
   }
   return std::vector <const reco::GenParticle*> (result.begin (), result.end());
 }

std::vector< const reco::GenParticle * > JetMatchingTools::getGenParticles ( const reco::GenJet & fJet )

GenParticles for GenJet.

Definition at line 305 of file JetMatchingTools.cc.

References reco::GenJet::getGenConstituents().

                                                                                             {
   return fJet.getGenConstituents ();
 }

const reco::CandidateCollection * JetMatchingTools::getGenParticlesCollection ( )

Definition at line 147 of file JetMatchingTools.cc.

References edm::Event::getByToken(), patZpeak::handle, input_cands_token_, mEvent, and mGenParticleCollection.

Referenced by getGenParticle().

                                                                             {
   if (!mGenParticleCollection) {
     edm::Handle<reco::CandidateCollection> handle;
     mEvent->getByToken (input_cands_token_, handle);
     mGenParticleCollection = &*handle;
   }
   return mGenParticleCollection;
 }

const HBHERecHitCollection * JetMatchingTools::getHBHERecHitCollection ( )

Definition at line 83 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_hbherechits_token_, mEvent, mHBHERecHitCollection, and HLT_25ns14e33_v3_cff::recHits.

Referenced by getConstituentHits().

                                                                        {
   if (!mHBHERecHitCollection) {
     edm::Handle<HBHERecHitCollection> recHits;
     mEvent->getByToken (input_hbherechits_token_, recHits);
     mHBHERecHitCollection = &*recHits;
   }
   return mHBHERecHitCollection;
 }

const PCaloHitContainer * JetMatchingTools::getHcalSimHitCollection ( )

Definition at line 123 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_pcalohits_hcal_token_, mEvent, mHcalSimHitCollection, and trackerHits::simHits.

Referenced by getPCaloHits().

                                                                     {
   if (!mHcalSimHitCollection) {
     edm::Handle<PCaloHitContainer> simHits;
     mEvent->getByToken (input_pcalohits_hcal_token_, simHits);
     mHcalSimHitCollection = &*simHits;
   }
   return mHcalSimHitCollection;
 }

const HFRecHitCollection * JetMatchingTools::getHFRecHitCollection ( )

Definition at line 99 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_hfrechits_token_, mEvent, mHFRecHitCollection, and HLT_25ns14e33_v3_cff::recHits.

Referenced by getConstituentHits().

                                                                    {
   if (!mHFRecHitCollection) {
     edm::Handle<HFRecHitCollection> recHits;
     mEvent->getByToken (input_hfrechits_token_, recHits);
     mHFRecHitCollection = &*recHits;
   }
   return mHFRecHitCollection;
 }

const HORecHitCollection * JetMatchingTools::getHORecHitCollection ( )

Definition at line 91 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_horechits_token_, mEvent, mHORecHitCollection, and HLT_25ns14e33_v3_cff::recHits.

Referenced by getConstituentHits().

                                                                    {
   if (!mHORecHitCollection) {
     edm::Handle<HORecHitCollection> recHits;
     mEvent->getByToken (input_horechits_token_, recHits);
     mHORecHitCollection = &*recHits;
   }
   return mHORecHitCollection;
 }

std::vector< const PCaloHit * > JetMatchingTools::getPCaloHits ( DetId fId )

get PCaloHits contributing to the detId

Definition at line 215 of file JetMatchingTools.cc.

References DetId::det(), DetId::Ecal, EcalBarrel, EcalEndcap, getEBSimHitCollection(), getEESimHitCollection(), getHcalSimHitCollection(), DetId::Hcal, query::result, and DetId::subdetId().

Referenced by getGenParticles(), and lostEnergyFraction().

                                                                      {
   std::vector <const PCaloHit*> result;
   if (fId.det () == DetId::Ecal) {
     if ((EcalSubdetector) fId.subdetId () == EcalBarrel) {
       result = getSimHits (*getEBSimHitCollection (), fId);
     } 
     else if ((EcalSubdetector) fId.subdetId () == EcalEndcap) {
       result = getSimHits (*getEESimHitCollection (), fId);
     }
   }
   else if (fId.det () == DetId::Hcal) {
     result = getSimHits (*getHcalSimHitCollection (), fId);
   }
   return result;
 }

std::vector<const PCaloHit*> JetMatchingTools::getPCaloHits ( int fGeneratorId )

CaloSimHits.

const SimTrackContainer * JetMatchingTools::getSimTrackCollection ( )

Definition at line 131 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_simtrack_token_, mEvent, mSimTrackCollection, and trackerHits::simHits.

Referenced by getTrack().

                                                                   {
   if (!mSimTrackCollection) {
     edm::Handle<SimTrackContainer> simHits;
     mEvent->getByToken (input_simtrack_token_, simHits);
     mSimTrackCollection = &*simHits;
   }
   return mSimTrackCollection;
 }

const SimVertexContainer * JetMatchingTools::getSimVertexCollection ( )

Definition at line 139 of file JetMatchingTools.cc.

References edm::Event::getByToken(), input_simvertex_token_, mEvent, mSimVertexCollection, and trackerHits::simHits.

Referenced by generatorId().

                                                                     {
   if (!mSimVertexCollection) {
     edm::Handle<SimVertexContainer> simHits;
     mEvent->getByToken (input_simvertex_token_, simHits);
     mSimVertexCollection = &*simHits;
   }
   return mSimVertexCollection;
 }

const SimTrack * JetMatchingTools::getTrack ( unsigned fSimTrackId )

convert trackId to SimTrack

Definition at line 235 of file JetMatchingTools.cc.

References getSimTrackCollection(), and i.

Referenced by generatorId().

                                                                 {
   for (unsigned i = 0; i < getSimTrackCollection ()->size (); ++i) {
     if ((*getSimTrackCollection ())[i].trackId() == fSimTrackId) return &(*getSimTrackCollection ())[i];
   }
   return 0;
 }

int JetMatchingTools::getTrackId ( const PCaloHit & fHit )

GEANT track ID.

Definition at line 231 of file JetMatchingTools.cc.

References PCaloHit::geantTrackId().

Referenced by getGenParticles(), and lostEnergyFraction().

                                                       {
   return fHit.geantTrackId ();
 }

double JetMatchingTools::lostEnergyFraction ( const reco::CaloJet & fJet )

energy in broken links

Definition at line 310 of file JetMatchingTools.cc.

References generatorId(), getConstituentHits(), getConstituents(), getPCaloHits(), getTrackId(), HLT_25ns14e33_v3_cff::recHits, and HLT_25ns14e33_v1_cff::towers.

                                                                      {
   double totalEnergy = 0;
   double lostEnergy = 0;
   // follow the chain
   std::vector <const CaloTower*> towers = getConstituents (fJet) ;
   for (unsigned itower = 0; itower < towers.size (); ++itower) {
     std::vector<JetConstituent> recHits = getConstituentHits(*(towers[itower]));
     for (unsigned ihit = 0; ihit < recHits.size(); ++ihit) {
       double foundSimEnergy = 0;
       double lostSimEnergy = 0;
       std::vector <const PCaloHit*> phits = getPCaloHits (recHits[ihit].id);
       for (unsigned iphit = 0; iphit < phits.size(); ++iphit) {
         double simEnergy = phits[iphit]->energy ();
         int trackId = getTrackId (*(phits[iphit]));
         if (trackId < 0 || generatorId (trackId) < 0)   lostSimEnergy += simEnergy;
         else   foundSimEnergy += simEnergy;
       }
       if (foundSimEnergy > 0 || lostSimEnergy > 0) {
         totalEnergy += recHits[ihit].energy;
         lostEnergy += recHits[ihit].energy * lostSimEnergy / (foundSimEnergy + lostSimEnergy);
       }
     }
   }
   return lostEnergy / totalEnergy;
 }

double JetMatchingTools::overlapEnergyFraction	(	const std::vector< const reco::GenParticle * > &	fObject,
		const std::vector< const reco::GenParticle * > &	fReference
	)		const

energy overlap

Definition at line 337 of file JetMatchingTools.cc.

References relval_parameters_module::energy, spr::find(), and i.

                                                                                                             {
   if (fObject.empty()) return 0;
   double totalEnergy = 0;
   double overlapEnergy = 0;
   for (unsigned i = 0; i < fObject.size(); ++i) {
     totalEnergy += fObject [i]->energy();
     if (find (fReference.begin(), fReference.end(), fObject [i]) != fReference.end ()) overlapEnergy += fObject [i]->energy();
   }
   return overlapEnergy / totalEnergy;
 }