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

Definition at line 12 of file PFClusterWidthAlgo.cc.

                                                                                      {
   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 auto& PFRecHits = pfclust[icl]->recHitFractions();
  
       for (auto 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->positionREP().phi(), scPhi);
         double dEta = RefPFRecHit->positionREP().eta() - scEta;
         numeratorEtaWidth += energyHit * dEta * dEta;
         numeratorPhiWidth += energyHit * dPhi * dPhi;
       }
     }  // end for ncluster
  
     //for the first cluster (from GSF) computed sigmaEtaEta
     const auto& PFRecHits = pfclust[0]->recHitFractions();
     for (auto it = PFRecHits.begin(); it != PFRecHits.end(); ++it) {
       const auto& RefPFRecHit = it->recHitRef();
       if (!RefPFRecHit.isAvailable())
         return;
       double energyHit = RefPFRecHit->energy();
       if (RefPFRecHit->detId() != SeedDetID) {
         float diffEta = RefPFRecHit->positionREP().eta() - SeedEta;
         sigmaEtaEta_ += (diffEta * diffEta) * (energyHit / SeedClusEnergy);
       }
     }
     if (sigmaEtaEta_ == 0.)
       sigmaEtaEta_ = 0.00000001;
  
     etaWidth_ = std::sqrt(numeratorEtaWidth / denominator);
     phiWidth_ = std::sqrt(numeratorPhiWidth / denominator);
  
   }  // endif ncluster > 0
 }