/data/refman/pasoursint/CMSSW_5_3_10/src/TopQuarkAnalysis/TopKinFitter/interface/CovarianceMatrix.h

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#ifndef CovarianceMatrix_h
#define CovarianceMatrix_h

#include "FWCore/ParameterSet/interface/ParameterSet.h"

#include "DataFormats/PatCandidates/interface/PATObject.h"
#include "DataFormats/PatCandidates/interface/Electron.h"
#include "DataFormats/PatCandidates/interface/Muon.h"
#include "DataFormats/PatCandidates/interface/Jet.h"
#include "DataFormats/PatCandidates/interface/MET.h"

#include "TopQuarkAnalysis/TopKinFitter/interface/TopKinFitter.h"
#include "TopQuarkAnalysis/TopObjectResolutions/interface/MET.h"
#include "TopQuarkAnalysis/TopObjectResolutions/interface/Jet.h"
#include "TopQuarkAnalysis/TopObjectResolutions/interface/Muon.h"
#include "TopQuarkAnalysis/TopObjectResolutions/interface/Electron.h"

/*
  \class   CovarianceMatrix CovarianceMatrix.h "TopQuarkAnalysis/TopKinFitter/interface/CovarianceMatrix.h"
  
  \brief   Helper class used to setup covariance matrices for given objects and known resolutions

  More details to be added here...
  
**/

class CovarianceMatrix {

 public:

  enum ObjectType{kUdscJet, kBJet, kMuon, kElectron, kMet};
  
  CovarianceMatrix(){};
  CovarianceMatrix(const std::vector<edm::ParameterSet> udscResolutions, const std::vector<edm::ParameterSet> bResolutions,
                   const std::vector<double> jetEnergyResolutionScaleFactors, const std::vector<double> jetEnergyResolutionEtaBinning);
  CovarianceMatrix(const std::vector<edm::ParameterSet> udscResolutions, const std::vector<edm::ParameterSet> bResolutions,
                   const std::vector<edm::ParameterSet> lepResolutions, const std::vector<edm::ParameterSet> metResolutions,
                   const std::vector<double> jetEnergyResolutionScaleFactors, const std::vector<double> jetEnergyResolutionEtaBinning);
  // destructor
  ~CovarianceMatrix(){};

  template <class T>
    TMatrixD setupMatrix(const pat::PATObject<T>& object, const TopKinFitter::Param param, const std::string& resolutionProvider = "");
  TMatrixD setupMatrix(const TLorentzVector& object, const ObjectType objType, const TopKinFitter::Param param);
  double getResolution(const TLorentzVector& object, const ObjectType objType, const std::string& whichResolution = "");
  template <class T>
    double getResolution(const pat::PATObject<T>& object, const std::string& whichResolution, const bool isBJet=false) {
    return getResolution(TLorentzVector(object.px(), object.py(), object.pz(), object.energy()), getObjectType(object, isBJet), whichResolution); }

 private:

  std::vector<std::string> binsUdsc_, binsB_, binsLep_, binsMet_;
  std::vector<std::string> funcEtUdsc_ , funcEtB_ , funcEtLep_ , funcEtMet_;
  std::vector<std::string> funcEtaUdsc_, funcEtaB_, funcEtaLep_, funcEtaMet_;
  std::vector<std::string> funcPhiUdsc_, funcPhiB_, funcPhiLep_, funcPhiMet_;
  const std::vector<double> jetEnergyResolutionScaleFactors_;
  const std::vector<double> jetEnergyResolutionEtaBinning_;

  template <class T>
    ObjectType getObjectType(const pat::PATObject<T>& object, const bool isBJet=false);
  template <class T>
    double getEtaDependentScaleFactor(const pat::PATObject<T>& object);
  double getEtaDependentScaleFactor(const TLorentzVector& object);

};

template <class T>
TMatrixD CovarianceMatrix::setupMatrix(const pat::PATObject<T>& object, const TopKinFitter::Param param, const std::string& resolutionProvider)
{
  // This part is for pat objects with resolutions embedded
  if(object.hasKinResolution()) {
    TMatrixD CovM3 (3,3); CovM3.Zero();
    TMatrixD CovM4 (4,4); CovM4.Zero();
    TMatrixD* CovM = &CovM3;
    switch(param){
    case TopKinFitter::kEtEtaPhi :
      CovM3(0,0) = pow(object.resolEt(resolutionProvider) , 2);
      if( dynamic_cast<const reco::Jet*>(&object) )
        CovM3(0,0)*=getEtaDependentScaleFactor(object); 
      if( dynamic_cast<const reco::MET*>(&object) )
        CovM3(1,1) = pow(9999., 2);
      else
        CovM3(1,1) = pow(object.resolEta(resolutionProvider), 2);
      CovM3(2,2) = pow(object.resolPhi(resolutionProvider), 2);
      CovM = &CovM3;
      break;
    case TopKinFitter::kEtThetaPhi :
      CovM3(0,0) = pow(object.resolEt(resolutionProvider)   , 2);
      if( dynamic_cast<const reco::Jet*>(&object) )
        CovM3(0,0)*=getEtaDependentScaleFactor(object); 
      CovM3(1,1) = pow(object.resolTheta(resolutionProvider), 2);
      CovM3(2,2) = pow(object.resolPhi(resolutionProvider)  , 2);
      CovM = &CovM3;
      break;
    case TopKinFitter::kEMom :
      CovM4(0,0) = pow(1, 2);
      CovM4(1,1) = pow(1, 2);
      CovM4(2,2) = pow(1, 2);
      CovM4(3,3) = pow(1, 2);
      CovM = &CovM4;
      break;
    }
    return *CovM;
  }
  // This part is for objects without resolutions embedded
  else {
    const ObjectType objType = getObjectType(object, (resolutionProvider=="bjets"));
    const TLorentzVector p4(object.px(), object.py(), object.pz(), object.energy());
    return setupMatrix(p4, objType, param);
  }
}

template <class T>
CovarianceMatrix::ObjectType CovarianceMatrix::getObjectType(const pat::PATObject<T>& object, const bool isBJet)
{
  ObjectType objType;
  // jets
  if( dynamic_cast<const reco::Jet*>(&object) ) {
    if(isBJet)
      objType = kBJet;
    else
      objType = kUdscJet;
  }
  // muons
  else if( dynamic_cast<const reco::Muon*>(&object) )
    objType = kMuon;
  // electrons
  else if( dynamic_cast<const reco::GsfElectron*>(&object) ) 
    objType = kElectron;
  // MET
  else if( dynamic_cast<const reco::MET*>(&object) )
    objType = kMet;
  // catch anything else
  else
    throw cms::Exception("UnsupportedObject") << "The object given is not supported!\n";
  return objType;
}

template <class T>
double CovarianceMatrix::getEtaDependentScaleFactor(const pat::PATObject<T>& object)
{
  double etaDependentScaleFactor = 1.;
  for(unsigned int i=0; i<jetEnergyResolutionEtaBinning_.size(); i++){
    if(std::abs(object.eta())>=jetEnergyResolutionEtaBinning_[i] && jetEnergyResolutionEtaBinning_[i]>=0.){
      if(i==jetEnergyResolutionEtaBinning_.size()-1) {
        edm::LogWarning("CovarianceMatrix") << "object eta ("<<std::abs(object.eta())<<") beyond last eta bin ("<<jetEnergyResolutionEtaBinning_[i]<<") using scale factor 1.0!";
        etaDependentScaleFactor=1.;
        break;
      }
      etaDependentScaleFactor=jetEnergyResolutionScaleFactors_[i];
    }
    else
      break;
  }
  return etaDependentScaleFactor;
}

#endif