#include <PFClusterWidthAlgo.h>

Public Member Functions
	PFClusterWidthAlgo (const std::vector< const reco::PFCluster * > &pfclust)

double	pflowEtaWidth () const

double	pflowPhiWidth () const

double	pflowSigmaEtaEta () const

	~PFClusterWidthAlgo ()

Private Attributes
double	etaWidth_

double	phiWidth_

double	sigmaEtaEta_

Detailed Description

Definition at line 6 of file PFClusterWidthAlgo.h.

Constructor & Destructor Documentation

PFClusterWidthAlgo::PFClusterWidthAlgo ( const std::vector< const reco::PFCluster * > & pfclust )

Definition at line 14 of file PFClusterWidthAlgo.cc.

References reco::deltaPhi(), cuy::denominator, dPhi(), edm::Ref< C, T, F >::isAvailable(), and mathSSE::sqrt().

                                                                                       {
 
 
   double numeratorEtaWidth = 0.;
   double numeratorPhiWidth = 0.;
   double sclusterE = 0.;
   double posX = 0.;
   double posY = 0.;
   double posZ = 0.;
   sigmaEtaEta_ = 0.;
 
   unsigned int nclust= pfclust.size();
   if(nclust == 0 ) {
     etaWidth_ = 0.;
     phiWidth_ = 0.;
     sigmaEtaEta_ = 0.;
   }
   else {
     
     //first loop, compute supercluster position at ecal face, and energy sum from rechit loop
     //in order to be consistent with variance calculation
     for(unsigned int icl=0; icl<nclust; ++icl) {
       const std::vector< reco::PFRecHitFraction >& PFRecHits =  pfclust[icl]->recHitFractions();
       
       for ( std::vector< reco::PFRecHitFraction >::const_iterator it = PFRecHits.begin(); 
             it != PFRecHits.end(); ++it) {
         const PFRecHitRef& RefPFRecHit = it->recHitRef(); 
         //compute rechit energy taking into account fractions
         double energyHit = RefPFRecHit->energy()*it->fraction();
 
         sclusterE += energyHit;
         posX += energyHit*RefPFRecHit->position().X();
         posY += energyHit*RefPFRecHit->position().Y();
         posZ += energyHit*RefPFRecHit->position().Z();
       
       }
     } // end for ncluster    
 
     double denominator = sclusterE;
     
     posX /=sclusterE;
     posY /=sclusterE;
     posZ /=sclusterE;
 
     math::XYZPoint pflowSCPos(posX,posY,posZ);
 
     double scEta    = pflowSCPos.eta();
     double scPhi    = pflowSCPos.phi();    
     
     double SeedClusEnergy = -1.;
     unsigned int SeedDetID = 0;
     double SeedEta = -1.;
 
     //second loop, compute variances
     for(unsigned int icl=0; icl<nclust; ++icl) {
       const std::vector< reco::PFRecHitFraction >& PFRecHits =  pfclust[icl]->recHitFractions();  
       
       for ( std::vector< reco::PFRecHitFraction >::const_iterator it = PFRecHits.begin(); 
         it != PFRecHits.end(); ++it) {
     const PFRecHitRef& RefPFRecHit = it->recHitRef(); 
         //compute rechit energy taking into account fractions
     double energyHit = RefPFRecHit->energy()*it->fraction();
 
     //only for the first cluster (from GSF) find the seed
     if(icl==0) {
       if (energyHit > SeedClusEnergy) {
         SeedClusEnergy = energyHit;
         SeedEta = RefPFRecHit->position().eta();
         SeedDetID = RefPFRecHit->detId();
       }
     }
 
     double dPhi = reco::deltaPhi(RefPFRecHit->position().phi(),scPhi);
     double dEta = RefPFRecHit->position().eta() - scEta;
     numeratorEtaWidth += energyHit * dEta * dEta;
     numeratorPhiWidth += energyHit * dPhi * dPhi;
       }
     } // end for ncluster
 
     //for the first cluster (from GSF) computed sigmaEtaEta
     const std::vector< reco::PFRecHitFraction >& PFRecHits =  pfclust[0]->recHitFractions();
     for ( std::vector< reco::PFRecHitFraction >::const_iterator it = PFRecHits.begin(); 
       it != PFRecHits.end(); ++it) {
       const PFRecHitRef& RefPFRecHit = it->recHitRef(); 
       if(!RefPFRecHit.isAvailable()) 
     return;
       double energyHit = RefPFRecHit->energy();
       if (RefPFRecHit->detId() != SeedDetID) {
     float diffEta =  RefPFRecHit->position().eta() - SeedEta;
     sigmaEtaEta_ += (diffEta*diffEta) * (energyHit/SeedClusEnergy);
       }
     }
     if (sigmaEtaEta_ == 0.) sigmaEtaEta_ = 0.00000001;
 
     etaWidth_ = sqrt(numeratorEtaWidth / denominator);
     phiWidth_ = sqrt(numeratorPhiWidth / denominator);
     
 
   } // endif ncluster > 0
 }