RegressionHelper.cc

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#include "Geometry/Records/interface/CaloTopologyRecord.h"
#include "CondFormats/DataRecord/interface/GBRWrapperRcd.h"

#include "RecoEgamma/EgammaElectronAlgos/interface/RegressionHelper.h"
#include "RecoEcal/EgammaCoreTools/interface/EcalClusterTools.h"
#include "RecoEgamma/EgammaTools/interface/EcalRegressionData.h"
#include "DataFormats/Math/interface/deltaR.h"
#include "TVector2.h"
#include "TFile.h"

RegressionHelper::RegressionHelper( const Configuration & config):
  cfg_(config),ecalRegressionInitialized_(false),combinationRegressionInitialized_(false),
  caloTopologyCacheId_(0), caloGeometryCacheId_(0),regressionCacheId_(0)
{;}

RegressionHelper::~RegressionHelper(){;}

void RegressionHelper::applyEcalRegression(reco::GsfElectron & ele,
                       const edm::Handle<reco::VertexCollection>& vertices,
                       const edm::Handle<EcalRecHitCollection>& rechitsEB,
                       const edm::Handle<EcalRecHitCollection>& rechitsEE) const {
  double cor, err;
  getEcalRegression(*ele.superCluster(), vertices, rechitsEB, rechitsEE, cor, err);
  ele.setCorrectedEcalEnergy(cor * ele.superCluster()->correctedEnergy());
  ele.setCorrectedEcalEnergyError( err * ele.superCluster()->correctedEnergy());    

}

void RegressionHelper::checkSetup(const edm::EventSetup & es) {

  // Topology 
  unsigned long long newCaloTopologyCacheId 
    = es.get<CaloTopologyRecord>().cacheIdentifier() ;
  if (!caloTopologyCacheId_ || ( caloTopologyCacheId_ != newCaloTopologyCacheId ) )
    {
      caloTopologyCacheId_ = newCaloTopologyCacheId;
      edm::ESHandle<CaloTopology> caloTopo;
      es.get<CaloTopologyRecord>().get(caloTopo);
      caloTopology_ = &(*caloTopo);
    }
    
  // Geometry
  unsigned long long newCaloGeometryCacheId
    = es.get<CaloGeometryRecord>().cacheIdentifier() ;
  if (!caloGeometryCacheId_ || ( caloGeometryCacheId_ != newCaloGeometryCacheId ) ) 
    {
      caloGeometryCacheId_ = newCaloGeometryCacheId;
      edm::ESHandle<CaloGeometry> caloGeom;
      es.get<CaloGeometryRecord>().get(caloGeom);
      caloGeometry_ = &(*caloGeom);
    }

  // Ecal regression 
  
  // if at least one of the set of weights come from the DB
  if(cfg_.ecalWeightsFromDB)
    {
      unsigned long long newRegressionCacheId
    = es.get<GBRWrapperRcd>().cacheIdentifier() ;
      if ( !regressionCacheId_ || (newRegressionCacheId != regressionCacheId_ ) ) {
    
    const GBRWrapperRcd& gbrRcd = es.get<GBRWrapperRcd>();

    // ECAL barrel
    edm::ESHandle<GBRForest> ecalRegBarrelH;
    gbrRcd.get(cfg_.ecalRegressionWeightLabels[0].c_str(),ecalRegBarrelH);
    ecalRegBarrel_ = &(*ecalRegBarrelH);
    
    // ECAL endcaps
    edm::ESHandle<GBRForest> ecalRegEndcapH;
    gbrRcd.get(cfg_.ecalRegressionWeightLabels[1].c_str(),ecalRegEndcapH);
    ecalRegEndcap_= &(*ecalRegEndcapH);
    
    // ECAL barrel error
    edm::ESHandle<GBRForest> ecalRegErrorBarrelH;
    gbrRcd.get(cfg_.ecalRegressionWeightLabels[2].c_str(),ecalRegErrorBarrelH);
    ecalRegErrorBarrel_ = &(*ecalRegErrorBarrelH);
    
    // ECAL endcap error
    edm::ESHandle<GBRForest> ecalRegErrorEndcapH;
    gbrRcd.get(cfg_.ecalRegressionWeightLabels[3].c_str(),ecalRegErrorEndcapH);
    ecalRegErrorEndcap_ = &(*ecalRegErrorEndcapH);
    
    ecalRegressionInitialized_ = true;
      }
    }
  if( cfg_.combinationWeightsFromDB) 
    {

    // Combination
    if(cfg_.combinationWeightsFromDB) 
      {
        unsigned long long newRegressionCacheId
          = es.get<GBRWrapperRcd>().cacheIdentifier() ;
        if ( !regressionCacheId_ || (newRegressionCacheId != regressionCacheId_ ) ) {

          const GBRWrapperRcd& gbrRcd = es.get<GBRWrapperRcd>();

          edm::ESHandle<GBRForest> combinationRegH;
          gbrRcd.get(cfg_.combinationRegressionWeightLabels[0].c_str(),combinationRegH);
          combinationReg_ = &(*combinationRegH);
          
          combinationRegressionInitialized_ = true;
        }
      }
    }

  // read weights from file - for debugging. Even if it is one single files, 4 files should b set in the vector
  if(!cfg_.ecalWeightsFromDB && !ecalRegressionInitialized_ &&
     !cfg_.ecalRegressionWeightFiles.empty() ) {
    TFile file0 (edm::FileInPath(cfg_.ecalRegressionWeightFiles[0].c_str()).fullPath().c_str());
    ecalRegBarrel_ = (const GBRForest*)file0.Get(cfg_.ecalRegressionWeightLabels[0].c_str());
    file0.Close();
    TFile file1 (edm::FileInPath(cfg_.ecalRegressionWeightFiles[1].c_str()).fullPath().c_str());
    ecalRegEndcap_ = (const GBRForest*)file1.Get(cfg_.ecalRegressionWeightLabels[1].c_str());
    file1.Close();
    TFile file2 (edm::FileInPath(cfg_.ecalRegressionWeightFiles[2].c_str()).fullPath().c_str());
    ecalRegErrorBarrel_ = (const GBRForest*)file2.Get(cfg_.ecalRegressionWeightLabels[2].c_str());
    file2.Close();
    TFile file3 (edm::FileInPath(cfg_.ecalRegressionWeightFiles[3].c_str()).fullPath().c_str());
    ecalRegErrorEndcap_ = (const GBRForest*)file3.Get(cfg_.ecalRegressionWeightLabels[3].c_str());
    ecalRegressionInitialized_ = true;
    file3.Close();
  }
  
  if(!cfg_.combinationWeightsFromDB && !combinationRegressionInitialized_ && 
     !cfg_.combinationRegressionWeightFiles.empty() ) 
    {
      TFile file0 (edm::FileInPath(cfg_.combinationRegressionWeightFiles[0].c_str()).fullPath().c_str());
      combinationReg_ = (const GBRForest*)file0.Get(cfg_.combinationRegressionWeightLabels[0].c_str());
      combinationRegressionInitialized_ = true;
      file0.Close();
    }
  
}

void RegressionHelper::readEvent( const edm::Event &) {;}

void RegressionHelper::getEcalRegression(const reco::SuperCluster & sc,
                     const edm::Handle<reco::VertexCollection>& vertices,
                     const edm::Handle<EcalRecHitCollection>& rechitsEB,
                     const edm::Handle<EcalRecHitCollection>& rechitsEE,
                     double & energyFactor, double & errorFactor) const {
  
  energyFactor = -999.;
  errorFactor = -999.;

  std::vector<float> rInputs;
  EcalRegressionData regData;
  regData.fill(sc,rechitsEB.product(),rechitsEE.product(),caloGeometry_,caloTopology_,vertices.product());
  regData.fillVec(rInputs);
  if(sc.seed()->hitsAndFractions()[0].first.subdetId()==EcalBarrel){
    energyFactor = ecalRegBarrel_->GetResponse(&rInputs[0]);
    errorFactor = ecalRegErrorBarrel_->GetResponse(&rInputs[0]);
  }else if(sc.seed()->hitsAndFractions()[0].first.subdetId()==EcalEndcap){  
    energyFactor = ecalRegEndcap_->GetResponse(&rInputs[0]);
    errorFactor = ecalRegErrorEndcap_->GetResponse(&rInputs[0]);
  }else{
    throw cms::Exception("RegressionHelper::calculateRegressedEnergy")
      << "Supercluster seed is either EB nor EE!" << std::endl;
  }

}

void RegressionHelper::applyCombinationRegression(reco::GsfElectron & ele) const
{
  float energy = ele.correctedEcalEnergy();
  float energyError = ele.correctedEcalEnergyError();
  float momentum = ele.trackMomentumAtVtx().R();
  float momentumError = ele.trackMomentumError();
  int elClass = -.1;
  
  switch (ele.classification()) {
  case reco::GsfElectron::GOLDEN:
    elClass = 0;
    break;
  case reco::GsfElectron::BIGBREM:
    elClass = 1;
    break;
  case reco::GsfElectron::BADTRACK:
    elClass = 2;
    break;
  case  reco::GsfElectron::SHOWERING:
    elClass = 3;
    break;
  case reco::GsfElectron::GAP:
    elClass = 4;
    break;
  default:
    elClass = -1;
  }


  bool isEcalDriven = ele.ecalDriven();
  bool isTrackerDriven =  ele.trackerDrivenSeed();
  bool isEB = ele.isEB();
  
  // compute relative errors and ratio of errors
  float energyRelError = energyError / energy;
  float momentumRelError = momentumError / momentum;
  float errorRatio = energyRelError / momentumRelError;

  // calculate E/p and corresponding error
  float eOverP = energy / momentum;  
  float eOverPerror = eOverP*std::hypot(energyRelError,momentumRelError);
  
  // fill input variables
  std::vector<float> regressionInputs ;
  regressionInputs.resize(11,0.);
  
  regressionInputs[0]  = energy;
  regressionInputs[1]  = energyRelError;
  regressionInputs[2]  = momentum;
  regressionInputs[3]  = momentumRelError;
  regressionInputs[4]  = errorRatio;
  regressionInputs[5]  = eOverP;
  regressionInputs[6]  = eOverPerror;
  regressionInputs[7]  = static_cast<float>(isEcalDriven);
  regressionInputs[8]  = static_cast<float>(isTrackerDriven);
  regressionInputs[9]  = static_cast<float>(elClass);
  regressionInputs[10] = static_cast<float>(isEB);
  
  // retrieve combination weight
  float weight = 0.;
  if(eOverP>0.025 
     &&fabs(momentum-energy)<15.*sqrt(momentumError*momentumError + energyError*energyError)
     ) // protection against crazy track measurement
    {
      weight = combinationReg_->GetResponse(regressionInputs.data());
      if(weight>1.) weight = 1.;
      else if(weight<0.) weight = 0.;
    }
  
  float combinedMomentum = weight*momentum + (1.-weight)*energy;
  float combinedMomentumError = sqrt(weight*weight*momentumError*momentumError + (1.-weight)*(1.-weight)*energyError*energyError);
  
  // FIXME : pure tracker electrons have track momentum error of 999.
  // If the combination try to combine such electrons then the original combined momentum is kept
  if(momentumError!=999. || weight==0.)
    {
      math::XYZTLorentzVector oldMomentum = ele.p4() ;
      math::XYZTLorentzVector newMomentum(oldMomentum.x()*combinedMomentum/oldMomentum.t(),
                      oldMomentum.y()*combinedMomentum/oldMomentum.t(),
                      oldMomentum.z()*combinedMomentum/oldMomentum.t(),
                      combinedMomentum);
      
      ele.setP4(reco::GsfElectron::P4_COMBINATION,newMomentum,combinedMomentumError,true);
    }  
}