TRT_ToT_dEdx.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
#include "TRT_ToT_dEdx.h"
#include "TRT_ElectronPidTools/TRT_ToT_Corrections.h"
 
#include "GaudiKernel/MsgStream.h"
#include "GaudiKernel/IToolSvc.h"
 
#include "InDetIdentifier/TRT_ID.h"
#include "InDetRIO_OnTrack/TRT_DriftCircleOnTrack.h"
 
#include "TrkSurfaces/Surface.h"
 
#include "GaudiKernel/IChronoStatSvc.h"
 
#include "TF1.h"
 
#include "StoreGate/DataHandle.h"
#include "StoreGate/ReadHandle.h"
#include "StoreGate/ReadCondHandle.h"
#include "StoreGate/ReadDecorHandle.h"
#include <cmath>
#include <limits>
 
namespace{
  bool
    inRange(const double val, const double lo, const double hi){
    return (val>lo) and (val<hi);
  }
}
 
// constructor
TRT_ToT_dEdx::TRT_ToT_dEdx(const std::string& t, const std::string& n, const IInterface* p) : AthAlgTool(t,n,p)
{
  declareInterface<ITRT_ToT_dEdx>(this);
}
 
 
// destructor
TRT_ToT_dEdx::~TRT_ToT_dEdx() = default;
 
 
 
// initialize
StatusCode TRT_ToT_dEdx::initialize()
{
 
  MsgStream log(msgSvc(), name());
 
  // retrieve TRT-ID helper
 
  StatusCode sc = detStore()->retrieve(m_trtId, "TRT_ID");
  if (sc.isFailure()){
    ATH_MSG_ERROR ( "Could not get TRT_ID helper !" );
    return StatusCode::FAILURE;
  }
 
  // Initialize ReadHandleKey and ReadCondHandleKey
  ATH_CHECK(m_rdhkEvtInfo.initialize());
  ATH_CHECK(m_ReadKey.initialize());
  ATH_CHECK(m_assoTool.retrieve());
  ATH_CHECK( m_localOccTool.retrieve() );
  ATH_CHECK(m_TRTStrawSummaryTool.retrieve());
 
  if (m_useTrackPartWithGasType > EGasType::kUnset ||
      m_useTrackPartWithGasType < EGasType::kXenon) {
    ATH_MSG_ERROR("Property TRT_dEdx_useTrackPartWithGasType has an invalid "
                  << "value: " << m_useTrackPartWithGasType);
    return StatusCode::FAILURE;
  }
 
  return StatusCode::SUCCESS;
}
 
bool
TRT_ToT_dEdx::isGoodHit(const EventContext& ctx,
                        const Trk::TrackStateOnSurface* trackState,
                        bool useHitsHT,
                        double& length) const
{
  const Trk::MeasurementBase* trkM = trackState->measurementOnTrack();
  if (!trkM)  {
    return false;
  }
 
  // Check if this is RIO on track
  // and if yes check if is TRT Drift Circle
  // then set the ptr
  const InDet::TRT_DriftCircleOnTrack* driftcircle = nullptr;
  if (trkM->type(Trk::MeasurementBaseType::RIO_OnTrack)) {
    const Trk::RIO_OnTrack* tmpRio = static_cast<const Trk::RIO_OnTrack*>(trkM);
    if (tmpRio->rioType(Trk::RIO_OnTrackType::TRT_DriftCircle)) {
      driftcircle = static_cast<const InDet::TRT_DriftCircleOnTrack*>(tmpRio);
    }
  }
 
  if (!driftcircle) {
    return false;
  }
 
  const Trk::TrackParameters* trkP = trackState->trackParameters();
  if(trkP==nullptr)return false;
 
  double Trt_Rtrack = std::abs(trkP->parameters()[Trk::locR]);
  double Trt_RHit = std::abs(driftcircle->localParameters()[Trk::driftRadius]);
  double error = std::sqrt(driftcircle->localCovariance()(Trk::driftRadius,Trk::driftRadius));
 
  if (trackState->type(Trk::TrackStateOnSurface::Outlier)) return false; //Outliers
  if (m_useZeroRHitCut && Trt_RHit==0 && error>1.) return false;    //Select precision hits only
  if ((Trt_Rtrack >= m_trackConfig_maxRtrack) || (Trt_Rtrack <= m_trackConfig_minRtrack)) return false; // drift radius close to wire or wall
 
  length = calculateTrackLengthInStraw(trackState, m_trtId);
 
  if (m_divideByL and length < 1.7) return false; // Length in the straw
 
  if (!useHitsHT) {
    int TrtHl = driftcircle->highLevel();
    if (TrtHl==1) return false;
  }
 
  if (m_useTrackPartWithGasType != kUnset) { // don't preselect hits
    if(m_useTrackPartWithGasType != gasTypeInStraw(ctx,trackState)) return false;
  }
 
  if (driftcircle->prepRawData()->timeOverThreshold()==0.) return false; // If ToT for this hit equal 0, skip it.
 
  return true;
}
 
double
TRT_ToT_dEdx::dEdx(const EventContext& ctx,
                   const Trk::Track* track,
                   bool useHitsHT,
                   std::optional<float> localOccupancy) const
{
  ATH_MSG_DEBUG("dEdx()");
 
  double nVtx=-1.;
  // Event information
  SG::ReadDecorHandle<xAOD::EventInfo,float> eventInfoDecor(m_rdhkEvtInfo,ctx);
  if(!eventInfoDecor.isPresent()) {
    REPORT_MESSAGE(MSG::FATAL) << "EventInfo decoration not available!";
    return 0;
  }
 
  //    Average interactions per crossing for the current BCID
  // TODO: we should really not hard-code a mu to nVtx conversion
  double mu = eventInfoDecor(0);
  if(m_isData) {
    nVtx = 1.3129 + 0.716194*mu + (-0.00475074)*mu*mu;
  }
  else {
    nVtx = 1.0897 + 0.748287*mu + (-0.00421788)*mu*mu;
  }
 
  if (!track) {
    return 0;
  }
  const Trk::TrackStates* vtsos = track->trackStateOnSurfaces();
  if (!vtsos) {
    return 0;
  }
 
  EGasType gasType;
  Trk::TrackStates::const_iterator itr  = vtsos->begin();
  Trk::TrackStates::const_iterator itre = vtsos->end();
  size_t vtos_size = vtsos->size();
  double correctionFactor = 1.;
 
  if (m_toolScenario==kAlgStandard) {
    std::vector<double> vecToT;
    vecToT.reserve(vtos_size);
    double ToTsum = 0;
 
    for ( ; itr!=itre ; ++itr) {
      double length = 0;
      if ( isGoodHit(ctx,(*itr), useHitsHT, length)) {
          double ToT_correct = correctToT_corrRZ(ctx,*itr, length);
          if (m_correctionType == kHitBased){
            correctionFactor = hitOccupancyCorrection(ctx,*itr);
            ToT_correct*=correctionFactor;
          }
        vecToT.push_back(ToT_correct);
      }
    }
 
    sort(vecToT.begin(), vecToT.end());
    size_t nhits = vecToT.size();
 
    if (m_divideByL) {
      nhits-=m_nTrunkateHits;
    }
 
    // Boost speed
    if (nhits<1) return 0.0;
 
    ToTsum = std::accumulate(vecToT.begin(), vecToT.end(), 0);
    if (m_correctionType == kTrackBased) {
      correctionFactor=trackOccupancyCorrection(ctx,track, useHitsHT,localOccupancy);
    } else {
      correctionFactor=correctNormalization(ctx,nVtx);
    }
    ToTsum*=correctionFactor;
    return ToTsum/nhits;
  }
 
  if(m_toolScenario==kAlgReweight || m_toolScenario==kAlgReweightTrunkOne) {
    std::vector<double> vecToT_Xe;
    vecToT_Xe.reserve(vtos_size/2);
    std::vector<double> vecToT_Ar;
    vecToT_Ar.reserve(vtos_size/2);
    std::vector<double> vecToT_Kr;
 
    if(m_useTrackPartWithGasType!=kUnset) {
      ATH_MSG_WARNING(
        "dEdX_Estimator():: Using m_toolScenario="
        << m_toolScenario << " scenario m_useTrackPartWithGasType is set to"
        << m_useTrackPartWithGasType
        << ", but kUnset is requiered. Check you tool configuration.");
    }
 
    for ( ; itr!=itre ; ++itr) {
      double length=0;
      if (isGoodHit(ctx,(*itr), useHitsHT, length)) {
        gasType=gasTypeInStraw(ctx,*itr);
          double ToT_correct = correctToT_corrRZ(ctx,*itr, length);
          if (m_correctionType == kHitBased) {
          correctionFactor = hitOccupancyCorrection(ctx,*itr);
        }
          ToT_correct*=correctionFactor;
        if(gasType==kXenon) {
          vecToT_Xe.push_back(ToT_correct);
        } else if (gasType==kArgon) {
            vecToT_Ar.push_back(ToT_correct);
        } else if (gasType==kKrypton) {
            vecToT_Kr.push_back(ToT_correct);
        } else {
          ATH_MSG_ERROR("dEdX_Estimator():: During scenario kAlgReweight variable gasTypeInStraw got value kUnset.");
        }
      }
    }
 
    sort(vecToT_Xe.begin(), vecToT_Xe.end());
    sort(vecToT_Ar.begin(), vecToT_Ar.end());
    sort(vecToT_Kr.begin(), vecToT_Kr.end());
 
    size_t nhitsXe = vecToT_Xe.size();
    size_t nhitsAr = vecToT_Ar.size();
    size_t nhitsKr = vecToT_Kr.size();
 
    if (m_divideByL) {
      if(m_toolScenario==kAlgReweight){
        if (nhitsXe>=m_nTrunkateHits) nhitsXe-=m_nTrunkateHits;
        if (nhitsAr>=m_nTrunkateHits) nhitsAr-=m_nTrunkateHits;
        if (nhitsKr>=m_nTrunkateHits) nhitsKr-=m_nTrunkateHits;
      } else {// kAlgReweightTrunkOne
        int trunkGas = kUnset;
        double maxToT = 0.;
            if (nhitsXe>0 && vecToT_Xe.at(nhitsXe-1)>maxToT) {
              trunkGas = kXenon;
              maxToT = vecToT_Xe.at(nhitsXe-1);
            }
            if(nhitsAr>0 && vecToT_Ar.at(nhitsAr-1)>maxToT){
              trunkGas = kArgon;
              maxToT = vecToT_Ar.at(nhitsAr-1);
            }
        if (nhitsKr>0 && vecToT_Kr.at(nhitsKr-1)>maxToT) {
          trunkGas = kKrypton;
        }
 
        if (trunkGas==kXenon) {
          nhitsXe-=m_nTrunkateHits;
        } else if (trunkGas==kArgon) {
          nhitsAr-=m_nTrunkateHits;
        } else if (trunkGas==kKrypton) {
          nhitsKr-=m_nTrunkateHits;
        }
      }
    }
 
    size_t nhits  = nhitsXe + nhitsAr + nhitsKr;
    if(nhits<1) return 0.0;
 
    double ToTsumXe = 0;
    double ToTsumAr = 0;
    double ToTsumKr = 0;
    for (size_t i = 0; i < nhitsXe;i++) {
      ToTsumXe+=vecToT_Xe[i];
    }
    for (size_t i = 0; i < nhitsAr;i++) {
      ToTsumAr+=vecToT_Ar[i];
    }
    for (size_t i = 0; i < nhitsKr;i++) {
      ToTsumKr+=vecToT_Kr[i];
    }
 
    ToTsumXe = (nhitsXe>0) ? ToTsumXe/nhitsXe : 0;
    ToTsumAr = (nhitsAr>0) ? ToTsumAr/nhitsAr : 0;
    ToTsumKr = (nhitsKr>0) ? ToTsumKr/nhitsKr : 0;
    double ToTsum = ToTsumXe*nhitsXe + ToTsumAr*nhitsAr + ToTsumKr*nhitsKr;
 
    if (m_correctionType == kTrackBased) {
      correctionFactor =
        trackOccupancyCorrection(ctx, track, true, localOccupancy);
    } else {
      correctionFactor = correctNormalization(ctx, nVtx);
    }
    ToTsum *= correctionFactor;
 
    return ToTsum/nhits;
  }
 
  ATH_MSG_ERROR("dEdX_Estimator():: m_toolScenario has wrong value "<<m_toolScenario<<"");
  return 0.;
}
 
double
TRT_ToT_dEdx::usedHits(const EventContext& ctx,
                       const Trk::Track* track,
                       bool useHitsHT) const
{
  ATH_MSG_DEBUG("usedHits()");
  EGasType gasType = kUnset;
 
  if (!track) {
    return 0;
  }
  const Trk::TrackStates* vtsos = track->trackStateOnSurfaces();
  if (!vtsos) {
    return 0;
  }
 
  Trk::TrackStates::const_iterator itr  = vtsos->begin();
  Trk::TrackStates::const_iterator itre = vtsos->end();
 
  if (m_toolScenario==kAlgStandard) {
    int nhits =0;
 
    for ( ; itr!=itre ; ++itr) {
      double length=0;
      if (isGoodHit(ctx,(*itr), useHitsHT, length)) {
        nhits++;
      }
    }
    if (m_divideByL) nhits -= m_nTrunkateHits;
    return nhits;
  } else if (m_toolScenario==kAlgReweight || m_toolScenario==kAlgReweightTrunkOne) {
    int nhits = 0;
    int nhitsXe = 0;
    int nhitsAr = 0;
    int nhitsKr = 0;
 
    if(m_useTrackPartWithGasType!=kUnset) {
      ATH_MSG_WARNING(
        "usedHits_Estimator():: Using m_toolScenario="
        << m_toolScenario << " scenario m_useTrackPartWithGasType is set to "
        << m_useTrackPartWithGasType
        << ", but kUnset is required. Check you tool configuration.");
    }
 
    for ( ; itr!=itre ; ++itr) {
      double length=0;
      if ( isGoodHit(ctx,(*itr), useHitsHT, length)) {
        gasType=gasTypeInStraw(ctx,*itr);
        if (gasType==kXenon) {
          nhitsXe++;
        } else if (gasType==kArgon) {
          nhitsAr++;
        } else if (gasType==kKrypton) {
          nhitsKr++;
        } else {
          ATH_MSG_ERROR("usedHits_Estimator():: During scenario kAlgReweight variable gasTypeInStraw got value kUnset.");
        }
      }
    }
 
    if (m_divideByL) {
      if(m_toolScenario==kAlgReweight){
        if(nhitsXe>0) nhitsXe -= m_nTrunkateHits;
        if(nhitsAr>0) nhitsAr -= m_nTrunkateHits;
        if(nhitsKr>0) nhitsKr -= m_nTrunkateHits;
      } else { // kAlgReweightTrunkOne
        if(nhitsXe>0 || nhitsAr>0 || nhitsKr>0)
          nhitsXe -= m_nTrunkateHits;
      }
    }
 
    nhits  = nhitsXe + nhitsAr + nhitsKr;
    return nhits;
  }
 
  ATH_MSG_ERROR("usedHits_Estimator():: m_toolScenario has wrong value "<<m_toolScenario<<"");
  return 0;
}
 
double
TRT_ToT_dEdx::getProb(const EventContext& ctx,
                      const Trk::TrackStateOnSurface* itr,
                      const double dEdx_obs,
                      const double pTrk,
                      Trk::ParticleHypothesis hypothesis,
                      int nUsedHits) const
{
  EGasType gasType = gasTypeInStraw(ctx, itr);
  return getProb(ctx,gasType, dEdx_obs, pTrk, hypothesis, nUsedHits);
}
 
double
TRT_ToT_dEdx::getProb(const EventContext& ctx,
                      EGasType gasType,
                      const double dEdx_obs,
                      const double pTrk,
                      Trk::ParticleHypothesis hypothesis,
                      int nUsedHits) const
{
  ATH_MSG_DEBUG("getProb():: gasTypeInStraw = "<<gasType<<"");
 
  SG::ReadCondHandle<TRTDedxcorrection> readHandle{m_ReadKey,ctx};
  const TRTDedxcorrection* dEdxCorrection{*readHandle};
  if (dEdxCorrection==nullptr) {
    ATH_MSG_ERROR(" getProb: Could not find any dEdxCorrection in CondStore. Return zero.");
    return 0;
  }
 
  if(gasType==kUnset) {
    ATH_MSG_DEBUG("getProb():: gasTypeInStraw set kUnset that is not allowed! Use gasTypeInStraw(*itr) to get gas type info for that hit first!");
    ATH_MSG_DEBUG("getProb():: Now gasTypeInStraw sets to kXenon.");
    gasType = kXenon;
  }
 
  double dEdx_pred = predictdEdx(ctx,gasType, pTrk, hypothesis);
  if (dEdx_pred==0) return 0.0;
  if (hypothesis==Trk::electron) {
    // correction for pTrk in [MeV]
    double factor = 1;
    double correct = 1+factor*(0.045*log10(pTrk)+0.885-1);
    dEdx_pred= dEdx_pred/correct;
  }
 
  double Resolution =
    dEdxCorrection->resolution[gasType][0] +
    dEdxCorrection->resolution[gasType][1] * (nUsedHits + 0.5) +
    dEdxCorrection->resolution[gasType][2] * (nUsedHits + 0.5) *
      (nUsedHits + 0.5) +
    dEdxCorrection->resolution[gasType][3] * (nUsedHits + 0.5) *
      (nUsedHits + 0.5) * (nUsedHits + 0.5);
  if (hypothesis == Trk::electron) {
    Resolution =
      dEdxCorrection->resolutionElectron[gasType][0] +
      dEdxCorrection->resolutionElectron[gasType][1] * (nUsedHits + 0.5) +
      dEdxCorrection->resolutionElectron[gasType][2] * (nUsedHits + 0.5) *
        (nUsedHits + 0.5) +
      dEdxCorrection->resolutionElectron[gasType][3] * (nUsedHits + 0.5) *
        (nUsedHits + 0.5) * (nUsedHits + 0.5);
  }
 
  double prob = std::exp( -0.5 * ( ( ( dEdx_obs - dEdx_pred ) / (Resolution*dEdx_pred) ) *
                             ( ( dEdx_obs - dEdx_pred ) / (Resolution*dEdx_pred) ) ))  ;
 
  ATH_MSG_DEBUG("getProb():: return "<<prob<<"");
  return prob;
}
 
double
TRT_ToT_dEdx::getTest(const EventContext& ctx,
                      const double dEdx_obs,
                      const double pTrk,
                      Trk::ParticleHypothesis hypothesis,
                      Trk::ParticleHypothesis antihypothesis,
                      int nUsedHits) const
{
  ATH_MSG_DEBUG("getTest()");
 
  EGasType gasType = kUnset;
  if ( dEdx_obs<=0. || pTrk<=0. || nUsedHits<=0 ) return 0.5;
 
  double Pone = getProb(ctx,gasType, dEdx_obs,pTrk,hypothesis,nUsedHits);
  double Ptwo = getProb(ctx,gasType, dEdx_obs,pTrk,antihypothesis,nUsedHits);
  if ((Pone+Ptwo) != 0) {
    ATH_MSG_DEBUG("getTest():: return "<<Pone/(Pone+Ptwo)<<"");
    return Pone/(Pone+Ptwo);
  } else {
    return 0.5;
  }
}
 
double
TRT_ToT_dEdx::predictdEdx(const EventContext& ctx,
                          const Trk::TrackStateOnSurface* itr,
                          const double pTrk,
                          Trk::ParticleHypothesis hypothesis) const
{
  EGasType gasType = gasTypeInStraw(ctx, itr);
  return predictdEdx(ctx,gasType, pTrk, hypothesis);
}
 
double
TRT_ToT_dEdx::predictdEdx(const EventContext& ctx,
                          EGasType gasType,
                          const double pTrk,
                          Trk::ParticleHypothesis hypothesis) const
{
  ATH_MSG_DEBUG("predictdEdx(): gasTypeInStraw = " << gasType << "");
 
  SG::ReadCondHandle<TRTDedxcorrection> readHandle{ m_ReadKey,ctx };
  const TRTDedxcorrection* dEdxCorrection{ *readHandle };
  if (dEdxCorrection == nullptr) {
    ATH_MSG_ERROR(" predictdEdx: Could not find any dEdxCorrection in "
                  "CondStore. Return zero.");
    return 0;
  }
 
  if (gasType == kUnset) {
    ATH_MSG_DEBUG(
      "predictdEdx():: gasTypeInStraw set kUnset that is not allowed! Use "
      "gasTypeInStraw(*itr) to get gas type info for that hit first!");
    ATH_MSG_DEBUG("predictdEdx():: Now gasTypeInStraw sets to kXenon.");
    gasType = kXenon;
  }
 
  double mass = Trk::ParticleMasses::mass[hypothesis];
 
  double betaGamma = pTrk/mass;
  // low momentum particle can create floating point error
  // do we need the check in the log parameter in addition? will create CPU increase
  // do we want to throw an assertion here?
  if (pTrk < 100)
    return 0;
  if (m_divideByL) {
    if (dEdxCorrection->paraDivideByLengthDedxP3[gasType] +
          1. / (std::pow(betaGamma,
                         dEdxCorrection->paraDivideByLengthDedxP5[gasType])) <=
        0)
      return 0;
    return dEdxCorrection->paraDivideByLengthDedxP1[gasType] /
           std::pow(std::sqrt((betaGamma * betaGamma) /
                              (1. + (betaGamma * betaGamma))),
                    dEdxCorrection->paraDivideByLengthDedxP4[gasType]) *
           (dEdxCorrection->paraDivideByLengthDedxP2[gasType] -
            std::pow(std::sqrt((betaGamma * betaGamma) /
                               (1. + (betaGamma * betaGamma))),
                     dEdxCorrection->paraDivideByLengthDedxP4[gasType]) -
            log(dEdxCorrection->paraDivideByLengthDedxP3[gasType] +
                1. / (std::pow(
                       betaGamma,
                       dEdxCorrection->paraDivideByLengthDedxP5[gasType]))));
  }
  if (dEdxCorrection->paraDedxP3[gasType] +
        1. / (std::pow(betaGamma, dEdxCorrection->paraDedxP5[gasType])) <=
      0)
    return 0;
  return dEdxCorrection->paraDedxP1[gasType] /
         std::pow(
           std::sqrt((betaGamma * betaGamma) / (1. + (betaGamma * betaGamma))),
           dEdxCorrection->paraDedxP4[gasType]) *
         (dEdxCorrection->paraDedxP2[gasType] -
          std::pow(
            std::sqrt((betaGamma * betaGamma) / (1. + (betaGamma * betaGamma))),
            dEdxCorrection->paraDedxP4[gasType]) -
          log(dEdxCorrection->paraDedxP3[gasType] +
              1. / (std::pow(betaGamma, dEdxCorrection->paraDedxP5[gasType]))));
 
  //return 0;
}
 
double
TRT_ToT_dEdx::mass(const EventContext& ctx,
                   const Trk::TrackStateOnSurface* itr,
                   const double pTrk,
                   double dEdx) const
{
  EGasType gasType = gasTypeInStraw(ctx,itr);
 
  ATH_MSG_DEBUG("mass(): gasTypeInStraw = "<<gasType<<"");
 
  SG::ReadCondHandle<TRTDedxcorrection> readHandle{m_ReadKey,ctx};
  const TRTDedxcorrection* dEdxCorrection{*readHandle};
  if(dEdxCorrection==nullptr)
    {
      ATH_MSG_ERROR(" mass: Could not find any dEdxCorrection in CondStore. Return zero.");
      return 0;
    }
 
  if(gasType==kUnset)
    {
      ATH_MSG_WARNING("mass():: gasTypeInStraw set kUnset that is not allowed! Use gasTypeInStraw(*itr) to get gas type info for that hit first!");
      ATH_MSG_WARNING("mass():: Now gasTypeInStraw sets to kXenon.");
      gasType = kXenon;
    }
  // only for testing purposes!!!!
  // note that dE/dx has to be corrected on track level first before value can be transferred to mass
  // this has to be tuned on user level
  static const double bg_min = 0.001;
  static const double bg_max = 3;   // maximal allowed bg
 
  static const std::string blumRolandiFunction =
    "( [0]/sqrt( (x*x/([5]*[5]))/(1.+(x*x/([5]*[5]))) )^[3] ) * ([1] - sqrt( "
    "(x*x/([5]*[5]))/(1.+(x*x/([5]*[5]))) )^[3] - log([2]+1./((x/[5])^[4]) ) )";
 
  TF1 blumRolandi( "BR", blumRolandiFunction.c_str(), 0.7, 100000);
 
  blumRolandi.SetParameters(dEdxCorrection->paraDedxP1[gasType],
                            dEdxCorrection->paraDedxP2[gasType],
                            dEdxCorrection->paraDedxP3[gasType],
                            dEdxCorrection->paraDedxP4[gasType],
                            dEdxCorrection->paraDedxP5[gasType],
                            1.);
  //blumRolandi.SetParameters(&dEdxCorrection->para_dEdx_BB);
  double betaGamma = blumRolandi.GetX(dEdx, bg_min, bg_max);
 
  ATH_MSG_DEBUG("mass():: return "<<pTrk/betaGamma<<"");
 
  return pTrk/betaGamma;
}
 
/* returns gas type for given straw */
// TODO: move this functionality to TRT_StrawStatusSummaryTool.
TRT_ToT_dEdx::EGasType TRT_ToT_dEdx::gasTypeInStraw(const EventContext& ctx,
                                                    const Trk::TrackStateOnSurface *itr) const
{
  const Trk::MeasurementBase* trkM = itr->measurementOnTrack();
  if (!trkM)  {
    return kUnset;
  }
 
  // Check if this is RIO on track
  //annd if yes check if is TRT Drift Circle
  //then set the ptr
  const InDet::TRT_DriftCircleOnTrack* driftcircle = nullptr;
  if (trkM->type(Trk::MeasurementBaseType::RIO_OnTrack)) {
    const Trk::RIO_OnTrack* tmpRio = static_cast<const Trk::RIO_OnTrack*>(trkM);
    if (tmpRio->rioType(Trk::RIO_OnTrackType::TRT_DriftCircle)) {
      driftcircle = static_cast<const InDet::TRT_DriftCircleOnTrack*>(tmpRio);
    }
  }
 
  if (!driftcircle) {
    return kUnset;
  }
 
  return gasTypeInStraw(ctx,driftcircle);
}
 
TRT_ToT_dEdx::EGasType
TRT_ToT_dEdx::gasTypeInStraw(
  const EventContext& ctx,
  const InDet::TRT_DriftCircleOnTrack* driftcircle) const
{
  Identifier DCid = driftcircle->identify();
 
  // getStatusHT returns enum {Undefined, Dead, Good, Xenon, Argon, Krypton, EmulatedArgon, EmulatedKrypton}.
  // Our representation of 'GasType' is 0:Xenon, 1:Argon, 2:Krypton
  EGasType GasType=kUnset; // kUnset is default
  if (!m_TRTStrawSummaryTool.empty()) {
    int stat = m_TRTStrawSummaryTool->getStatusHT(DCid,ctx);
    if       ( stat==2 || stat==3 ) { GasType = kXenon; } // Xe
    else if  ( stat==1 || stat==4 ) { GasType = kArgon; } // Ar
    else if  ( stat==5 )            { GasType = kKrypton; } // Kr
    else if  ( stat==6 )            { GasType = kArgon; } // Emulated Ar
    else if  ( stat==7 )            { GasType = kKrypton;
    } // Emulated Kr
    else {
      ATH_MSG_FATAL(
        "getStatusHT = "
        << stat
        << ", must be 'Good(2)||Xenon(3)' or 'Dead(1)||Argon(4)' or "
           "'Krypton(5)' or 'EmulatedArgon(6)' or 'EmulatedKr(7)'!");
      throw std::exception();
    }
  }
 
  return GasType;
}

// Corrections
 
double
TRT_ToT_dEdx::correctNormalization(const EventContext& ctx, double nVtx) const
{
  SG::ReadCondHandle<TRTDedxcorrection> readHandle{m_ReadKey,ctx};
  const TRTDedxcorrection* dEdxCorrection{*readHandle};
  if(dEdxCorrection==nullptr) {
    ATH_MSG_ERROR(" correctNormalization: Could not find any dEdxCorrection in CondStore. Return zero.");
    return 0;
  }
 
  EGasType gasType = static_cast<EGasType> (m_useTrackPartWithGasType.value());
  if (m_useTrackPartWithGasType==kUnset) gasType=kXenon;
  if (nVtx<=0) nVtx=dEdxCorrection->normNzero[gasType];
  double slope = dEdxCorrection->normSlopeTot[gasType];
  double offset = dEdxCorrection->normOffsetTot[gasType];
  if (m_divideByL){
    slope = dEdxCorrection->normSlopeTotDivideByLength[gasType];
    offset = dEdxCorrection->normOffsetTotDivideByLength[gasType];
  }
  double shift = dEdxCorrection->normOffsetData[gasType];
  if(!m_isData)shift = 0;
  return (slope*dEdxCorrection->normNzero[gasType]+offset)/(slope*nVtx+offset+shift);
}
 
double
TRT_ToT_dEdx::correctToT_corrRZ(const EventContext& ctx,
                                const Trk::TrackStateOnSurface* itr,
                                double length) const
{
  const Trk::MeasurementBase* trkM = itr->measurementOnTrack();
  const Trk::TrackParameters* trkP = itr->trackParameters();
 
  // Check if this is RIO on track
  // annd if yes check if is TRT Drift Circle
  // then set the ptr
  const InDet::TRT_DriftCircleOnTrack* driftcircle = nullptr;
  if (trkM && trkM->type(Trk::MeasurementBaseType::RIO_OnTrack)) {
    const Trk::RIO_OnTrack* tmpRio = static_cast<const Trk::RIO_OnTrack*>(trkM);
    if (tmpRio->rioType(Trk::RIO_OnTrackType::TRT_DriftCircle)) {
      driftcircle = static_cast<const InDet::TRT_DriftCircleOnTrack*>(tmpRio);
    }
  }
 
  if (!driftcircle) {
    return 0;
  }
  if (driftcircle->prepRawData()==nullptr) {
    return 0;
  }
 
  Identifier DCId = driftcircle->identify();
  double timeOverThreshold = driftcircle->prepRawData()->timeOverThreshold();
  if(timeOverThreshold==0) {
    ATH_MSG_WARNING("correctToT_corrRZ(const Trk::TrackStateOnSurface *itr):: ToT="<<timeOverThreshold<<". We must cut that hit in isGoodHit() !");
    return 0;
  }
  int hitPart =  m_trtId->barrel_ec(DCId);
  int StrawLayer = m_trtId->straw_layer(DCId);
  int Layer = m_trtId->layer_or_wheel(DCId);
  double hitRtrack = std::abs(trkP->parameters()[Trk::locR]);
  EGasType gasType = gasTypeInStraw(ctx,itr);
  if(gasType==kUnset) {
    ATH_MSG_ERROR("correctToT_corrRZ(const Trk::TrackStateOnSurface *itr):: Gas type in straw is kUnset! Return ToT = 0");
    return 0;
  }
 
  if(m_divideByL && length>0) timeOverThreshold = timeOverThreshold/length;
  if(!m_corrected) return timeOverThreshold;
  /* else correct */
 
  double hitZ = driftcircle->globalPosition().z();
  double trackx =  driftcircle->globalPosition().x();
  double tracky =  driftcircle->globalPosition().y();
  double hitPosR = std::sqrt(trackx*trackx+tracky*tracky);

  double ToTmip = 1;
  double valToT = 0;
  if(m_divideByL){
    if (abs(hitPart)==1) // Barrel
      valToT = fitFuncBarrel_corrRZL(ctx,gasType, hitRtrack, hitZ, Layer, StrawLayer);
    else // End-cap
      valToT = fitFuncEndcap_corrRZL(ctx,gasType, hitRtrack, hitPosR, Layer, hitZ>0?1:(hitZ<0?-1:0));
  }else{
    if (abs(hitPart)==1) // Barrel
      valToT = fitFuncBarrel_corrRZ(ctx,gasType, hitRtrack, hitZ, Layer, StrawLayer);
    else // End-cap
      valToT = fitFuncEndcap_corrRZ(ctx,gasType, hitRtrack, hitPosR, Layer, hitZ>0?1:(hitZ<0?-1:0));
  }
  if (std::isinf(valToT)) return 0.;
  if (valToT!=0) return ToTmip*timeOverThreshold/valToT;
  return 0.;
}
 
double
TRT_ToT_dEdx::fitFuncBarrel_corrRZ(const EventContext& ctx,
                                   EGasType gasType,
                                   double driftRadius,
                                   double zPosition,
                                   int Layer,
                                   int StrawLayer) const
{
  if (Layer == 0 && StrawLayer < 9) {
    return fitFuncBarrelShort_corrRZ(ctx,gasType, driftRadius, zPosition, StrawLayer);
  }
  return fitFuncBarrelLong_corrRZ(ctx,gasType, driftRadius, zPosition, Layer, StrawLayer);
}
 
double
TRT_ToT_dEdx::fitFuncEndcap_corrRZ(const EventContext& ctx,
                                   EGasType gasType,
                                   double driftRadius,
                                   double radialPosition,
                                   int Layer,
                                   int sign) const
{
  double T0 =  fitFuncPol_corrRZ(ctx,gasType, 0,driftRadius,Layer,0,sign,2);
  double a  =  fitFuncPol_corrRZ(ctx,gasType, 1,driftRadius,Layer,0,sign,2);
  return T0+a*radialPosition;
}
 
double
TRT_ToT_dEdx::fitFuncBarrelLong_corrRZ(const EventContext& ctx,
                                       EGasType gasType,
                                       double driftRadius,
                                       double zPosition,
                                       int Layer,
                                       int StrawLayer) const
{
  double z = std::abs(zPosition);
  int sign=1;
  if(zPosition<0)sign=-1;
  double l = 704.6;
  // define set of parameters for negative and positive z positions
  double T0 =  fitFuncPol_corrRZ(ctx,gasType, 0,driftRadius,Layer,StrawLayer,sign,0);
  double  v =  fitFuncPol_corrRZ(ctx,gasType, 1,driftRadius,Layer,StrawLayer,sign,0);
  double  s =  fitFuncPol_corrRZ(ctx,gasType, 2,driftRadius,Layer,StrawLayer,sign,0);
  //_in theory_ For IEEE-compatible type double, argument causes exp to overflow if outside [-708.4, 709.8]
  //however, overflow still seen when argument is 702; so I restrict these to -600, 600
  const double expArg=(z-l)/s;
  if (not inRange(expArg, -600.0,600.0)){
    return expArg>0 ? std::numeric_limits<double>::infinity():0.;
  }
  return T0+(z/v)*std::exp(expArg);
}
 
double
TRT_ToT_dEdx::fitFuncBarrelShort_corrRZ(const EventContext& ctx,
                                        EGasType gasType,
                                        double driftRadius,
                                        double zPosition,
                                        int StrawLayer) const
{
  double z = std::abs(zPosition);
  int sign=1;
  if(zPosition<0)sign=-1;
  double T0 = fitFuncPol_corrRZ(ctx,gasType, 0,driftRadius,0,StrawLayer,sign,1);
  double b  = fitFuncPol_corrRZ(ctx,gasType, 1,driftRadius,0,StrawLayer,sign,1);
  return T0+b*z;
}
 
double
TRT_ToT_dEdx::fitFuncPol_corrRZ(const EventContext& ctx,
                                EGasType gasType,
                                int parameter,
                                double driftRadius,
                                int Layer,
                                int Strawlayer,
                                int sign,
                                int set) const
{
  SG::ReadCondHandle<TRTDedxcorrection> readHandle{m_ReadKey,ctx};
  const TRTDedxcorrection* dEdxCorrection{*readHandle};
  if(dEdxCorrection==nullptr)
    {
      ATH_MSG_ERROR(" fitFuncPol_corrRZ: Could not find any dEdxCorrection in CondStore. Return zero.");
      return 0;
    }
 
  double a = 0;
  double b = 0;
  double c = 0;
  double d = 0;
  double e = 0;
  double f = 0;
  double r = driftRadius;
  int offset = 0;
  if(m_isData){
    if(set==0){ // long straws in barrel
      a = dEdxCorrection->paraLongCorrRZ[gasType][(6*parameter+0)*30*3+Layer*30+Strawlayer+offset];
      b = dEdxCorrection->paraLongCorrRZ[gasType][(6*parameter+1)*30*3+Layer*30+Strawlayer+offset];
      c = dEdxCorrection->paraLongCorrRZ[gasType][(6*parameter+2)*30*3+Layer*30+Strawlayer+offset];
      d = dEdxCorrection->paraLongCorrRZ[gasType][(6*parameter+3)*30*3+Layer*30+Strawlayer+offset];
      e = dEdxCorrection->paraLongCorrRZ[gasType][(6*parameter+4)*30*3+Layer*30+Strawlayer+offset];
      f = dEdxCorrection->paraLongCorrRZ[gasType][(6*parameter+5)*30*3+Layer*30+Strawlayer+offset];
 
    }else if (set ==1) { // short straws in barrel
      if(sign > 0) offset+=108;
      a = dEdxCorrection->paraShortCorrRZ[gasType][(6*parameter+0)*9+Layer+offset];
      b = dEdxCorrection->paraShortCorrRZ[gasType][(6*parameter+1)*9+Layer+offset];
      c = dEdxCorrection->paraShortCorrRZ[gasType][(6*parameter+2)*9+Layer+offset];
      d = dEdxCorrection->paraShortCorrRZ[gasType][(6*parameter+3)*9+Layer+offset];
      e = dEdxCorrection->paraShortCorrRZ[gasType][(6*parameter+4)*9+Layer+offset];
      f = dEdxCorrection->paraShortCorrRZ[gasType][(6*parameter+5)*9+Layer+offset];
    }else{  // straws in endcap
      if(sign >0) Layer+=14;
      a = dEdxCorrection->paraEndCorrRZ[gasType][(6*parameter+0)*28+Layer];
      b = dEdxCorrection->paraEndCorrRZ[gasType][(6*parameter+1)*28+Layer];
      c = dEdxCorrection->paraEndCorrRZ[gasType][(6*parameter+2)*28+Layer];
      d = dEdxCorrection->paraEndCorrRZ[gasType][(6*parameter+3)*28+Layer];
      e = dEdxCorrection->paraEndCorrRZ[gasType][(6*parameter+4)*28+Layer];
      f = dEdxCorrection->paraEndCorrRZ[gasType][(6*parameter+5)*28+Layer];
    }
  }else{
    if(set==0){ // long straws in barrel
      if(sign > 0) offset=1620;
      a = dEdxCorrection->paraLongCorrRZMC[gasType][(6*parameter+0)*30*3+Layer*30+Strawlayer+offset];
      b = dEdxCorrection->paraLongCorrRZMC[gasType][(6*parameter+1)*30*3+Layer*30+Strawlayer+offset];
      c = dEdxCorrection->paraLongCorrRZMC[gasType][(6*parameter+2)*30*3+Layer*30+Strawlayer+offset];
      d = dEdxCorrection->paraLongCorrRZMC[gasType][(6*parameter+3)*30*3+Layer*30+Strawlayer+offset];
      e = dEdxCorrection->paraLongCorrRZMC[gasType][(6*parameter+4)*30*3+Layer*30+Strawlayer+offset];
      f = dEdxCorrection->paraLongCorrRZMC[gasType][(6*parameter+5)*30*3+Layer*30+Strawlayer+offset];
    }else if (set ==1) { // short straws in barrel
      if(sign > 0) offset+=108;
      a = dEdxCorrection->paraShortCorrRZMC[gasType][(6*parameter+0)*9+Layer+offset];
      b = dEdxCorrection->paraShortCorrRZMC[gasType][(6*parameter+1)*9+Layer+offset];
      c = dEdxCorrection->paraShortCorrRZMC[gasType][(6*parameter+2)*9+Layer+offset];
      d = dEdxCorrection->paraShortCorrRZMC[gasType][(6*parameter+3)*9+Layer+offset];
      e = dEdxCorrection->paraShortCorrRZMC[gasType][(6*parameter+4)*9+Layer+offset];
      f = dEdxCorrection->paraShortCorrRZMC[gasType][(6*parameter+5)*9+Layer+offset];
    }else{  // straws in endcap
      if(sign >0) Layer+=14;
      a = dEdxCorrection->paraEndCorrRZMC[gasType][(6*parameter+0)*28+Layer];
      b = dEdxCorrection->paraEndCorrRZMC[gasType][(6*parameter+1)*28+Layer];
      c = dEdxCorrection->paraEndCorrRZMC[gasType][(6*parameter+2)*28+Layer];
      d = dEdxCorrection->paraEndCorrRZMC[gasType][(6*parameter+3)*28+Layer];
      e = dEdxCorrection->paraEndCorrRZMC[gasType][(6*parameter+4)*28+Layer];
      f = dEdxCorrection->paraEndCorrRZMC[gasType][(6*parameter+5)*28+Layer];
    }
  }
  return a+b*r+c*r*r+d*r*r*r+e*r*r*r*r+f*r*r*r*r*r;
}
 
double
TRT_ToT_dEdx::fitFuncEndcap_corrRZL(const EventContext& ctx,
                                    EGasType gasType,
                                    double driftRadius,
                                    double radialPosition,
                                    int Layer,
                                    int sign) const
{
  /*
   * T(r,R) = T0(r)+ a(r)*R
   */
 
  SG::ReadCondHandle<TRTDedxcorrection> readHandle{m_ReadKey,ctx};
  const TRTDedxcorrection* dEdxCorrection{*readHandle};
  if(dEdxCorrection==nullptr) {
    ATH_MSG_ERROR(" fitFuncEndcap_corrRZL: Could not find any dEdxCorrection in CondStore. Return zero.");
    return 0;
  }
 
  double r = std::abs(driftRadius);
  double a,b,c,d,e,f,g,h,i;
  if(sign >0) Layer+=14;
  if(m_isData){
    a = dEdxCorrection->paraEndCorrRZDivideByLengthDATA[gasType][(0)*28+Layer];
    b = dEdxCorrection->paraEndCorrRZDivideByLengthDATA[gasType][(1)*28+Layer];
    c = dEdxCorrection->paraEndCorrRZDivideByLengthDATA[gasType][(2)*28+Layer];
    d = dEdxCorrection->paraEndCorrRZDivideByLengthDATA[gasType][(3)*28+Layer];
    e = dEdxCorrection->paraEndCorrRZDivideByLengthDATA[gasType][(4)*28+Layer];
    f = dEdxCorrection->paraEndCorrRZDivideByLengthDATA[gasType][(5)*28+Layer];
    g = dEdxCorrection->paraEndCorrRZDivideByLengthDATA[gasType][(6)*28+Layer];
    h = dEdxCorrection->paraEndCorrRZDivideByLengthDATA[gasType][(7)*28+Layer];
    i = dEdxCorrection->paraEndCorrRZDivideByLengthDATA[gasType][(8)*28+Layer];
  }else{
    a = dEdxCorrection->paraEndCorrRZDivideByLengthMC[gasType][(0)*28+Layer];
    b = dEdxCorrection->paraEndCorrRZDivideByLengthMC[gasType][(1)*28+Layer];
    c = dEdxCorrection->paraEndCorrRZDivideByLengthMC[gasType][(2)*28+Layer];
    d = dEdxCorrection->paraEndCorrRZDivideByLengthMC[gasType][(3)*28+Layer];
    e = dEdxCorrection->paraEndCorrRZDivideByLengthMC[gasType][(4)*28+Layer];
    f = dEdxCorrection->paraEndCorrRZDivideByLengthMC[gasType][(5)*28+Layer];
    g = dEdxCorrection->paraEndCorrRZDivideByLengthMC[gasType][(6)*28+Layer];
    h = dEdxCorrection->paraEndCorrRZDivideByLengthMC[gasType][(7)*28+Layer];
    i = dEdxCorrection->paraEndCorrRZDivideByLengthMC[gasType][(8)*28+Layer];
  }
 
  double T1    = b*r+c*r*r+d*r*r*r+e*r*r*r*r+f*r*r*r*r*r;
  double slope = g+h*r+i*r*r;
  double T0    = a;
 
  return T0+T1+slope*radialPosition;
}
 
double
TRT_ToT_dEdx::fitFuncBarrel_corrRZL(const EventContext& ctx,
                                    EGasType gasType,
                                    double driftRadius,
                                    double zPosition,
                                    int Layer,
                                    int Strawlayer) const
{
  /*
   * T(r,z) = T0(r)+ b(r)*z*z
   */
  SG::ReadCondHandle<TRTDedxcorrection> readHandle{m_ReadKey,ctx};
  const TRTDedxcorrection* dEdxCorrection{*readHandle};
  if(dEdxCorrection==nullptr) {
    ATH_MSG_ERROR(" fitFuncBarrel_corrRZL: Could not find any dEdxCorrection in CondStore. Return zero.");
    return 0;
  }
 
  double a,b,c,d,e,f,g;
  if (Layer==0 && Strawlayer<9) { // short straws
    if (m_isData){
      a = dEdxCorrection->paraShortCorrRZDivideByLengthDATA[gasType][(0)*9+Strawlayer];
      b = dEdxCorrection->paraShortCorrRZDivideByLengthDATA[gasType][(1)*9+Strawlayer];
      c = dEdxCorrection->paraShortCorrRZDivideByLengthDATA[gasType][(2)*9+Strawlayer];
      d = dEdxCorrection->paraShortCorrRZDivideByLengthDATA[gasType][(3)*9+Strawlayer];
      e = dEdxCorrection->paraShortCorrRZDivideByLengthDATA[gasType][(4)*9+Strawlayer];
      f = dEdxCorrection->paraShortCorrRZDivideByLengthDATA[gasType][(5)*9+Strawlayer];
      g = dEdxCorrection->paraShortCorrRZDivideByLengthDATA[gasType][(6)*9+Strawlayer];
    } else {
      a = dEdxCorrection->paraShortCorrRZDivideByLengthMC[gasType][(0)*9+Strawlayer];
      b = dEdxCorrection->paraShortCorrRZDivideByLengthMC[gasType][(1)*9+Strawlayer];
      c = dEdxCorrection->paraShortCorrRZDivideByLengthMC[gasType][(2)*9+Strawlayer];
      d = dEdxCorrection->paraShortCorrRZDivideByLengthMC[gasType][(3)*9+Strawlayer];
      e = dEdxCorrection->paraShortCorrRZDivideByLengthMC[gasType][(4)*9+Strawlayer];
      f = dEdxCorrection->paraShortCorrRZDivideByLengthMC[gasType][(5)*9+Strawlayer];
      g = dEdxCorrection->paraShortCorrRZDivideByLengthMC[gasType][(6)*9+Strawlayer];
    }
  } else {
    if (m_isData) {
      a = dEdxCorrection->paraLongCorrRZDivideByLengthDATA[gasType][(0)*30*3+Layer*30+Strawlayer];
      b = dEdxCorrection->paraLongCorrRZDivideByLengthDATA[gasType][(1)*30*3+Layer*30+Strawlayer];
      c = dEdxCorrection->paraLongCorrRZDivideByLengthDATA[gasType][(2)*30*3+Layer*30+Strawlayer];
      d = dEdxCorrection->paraLongCorrRZDivideByLengthDATA[gasType][(3)*30*3+Layer*30+Strawlayer];
      e = dEdxCorrection->paraLongCorrRZDivideByLengthDATA[gasType][(4)*30*3+Layer*30+Strawlayer];
      f = dEdxCorrection->paraLongCorrRZDivideByLengthDATA[gasType][(5)*30*3+Layer*30+Strawlayer];
      g = dEdxCorrection->paraLongCorrRZDivideByLengthDATA[gasType][(6)*30*3+Layer*30+Strawlayer];
    } else {
      a = dEdxCorrection->paraLongCorrRZDivideByLengthMC[gasType][(0)*30*3+Layer*30+Strawlayer];
      b = dEdxCorrection->paraLongCorrRZDivideByLengthMC[gasType][(1)*30*3+Layer*30+Strawlayer];
      c = dEdxCorrection->paraLongCorrRZDivideByLengthMC[gasType][(2)*30*3+Layer*30+Strawlayer];
      d = dEdxCorrection->paraLongCorrRZDivideByLengthMC[gasType][(3)*30*3+Layer*30+Strawlayer];
      e = dEdxCorrection->paraLongCorrRZDivideByLengthMC[gasType][(4)*30*3+Layer*30+Strawlayer];
      f = dEdxCorrection->paraLongCorrRZDivideByLengthMC[gasType][(5)*30*3+Layer*30+Strawlayer];
      g = dEdxCorrection->paraLongCorrRZDivideByLengthMC[gasType][(6)*30*3+Layer*30+Strawlayer];
    }
  }
  double z = std::abs(zPosition);
  double r = std::abs(driftRadius);
  double T0neg=a;
  double T0pos=b;
  double T1 = std::exp(-c*r*r)+d*r;
  double slope = e*r+f*r*r+g*r*r*r;
  double result;
  result = T0neg+T1+slope*z;
  if (zPosition>0) result = T0pos+T1+slope*z;
 
  return result;
}
 
double
TRT_ToT_dEdx::hitOccupancyCorrection(const EventContext& ctx,
                                     const Trk::TrackStateOnSurface* itr) const
{
  SG::ReadCondHandle<TRTDedxcorrection> readHandle(m_ReadKey,ctx);
  const TRTDedxcorrection* dEdxCorrection{*readHandle};
 
  const Trk::MeasurementBase* trkM = itr->measurementOnTrack();
 
  // Check if this is RIO on track
  // and if yes check if is TRT Drift Circle
  // then set the ptr
  const InDet::TRT_DriftCircleOnTrack* driftcircle = nullptr;
  if (trkM && trkM->type(Trk::MeasurementBaseType::RIO_OnTrack)) {
    const Trk::RIO_OnTrack* tmpRio = static_cast<const Trk::RIO_OnTrack*>(trkM);
    if (tmpRio->rioType(Trk::RIO_OnTrackType::TRT_DriftCircle)) {
      driftcircle = static_cast<const InDet::TRT_DriftCircleOnTrack*>(tmpRio);
    }
  }
 
  if (!driftcircle) {
    return 0.;
  }
 
  const Trk::TrackParameters* trkP = itr->trackParameters();
  Identifier DCId = driftcircle->identify();
  int isHT = driftcircle->highLevel();
  int isShared=0;
 
  const Trk::RIO_OnTrack* hit_trt = nullptr;
  if (trkM && trkM->type(Trk::MeasurementBaseType::RIO_OnTrack)) {
    hit_trt = static_cast<const Trk::RIO_OnTrack*>(trkM);
  }
 
  if (hit_trt) {
    if ( m_assoTool->isShared(*(hit_trt->prepRawData())) ) isShared=1;
  }
  int layer = m_trtId->layer_or_wheel(DCId);
  int phimodule = m_trtId->phi_module(DCId);
  int HitPart =  m_trtId->barrel_ec(DCId);
  double Trt_HitTheta = trkP->parameters()[Trk::theta];
  double trackEta = -log(tan(Trt_HitTheta/2.0));
 
  double localOccupancy = m_localOccTool->LocalOccupancy(ctx, trackEta, phimodule);
  double ToTmip = 1;
  double valToT = 1.;
 
  double p0=0., p1=0., p2=0., p0_flat=0.;
 
  //the calibration array is structured as follows (hence the non intuitive numbers)
  //the first 36 parameters are for barrel, the last 168 for the endcap
  //each of these subarrays is divided into smaller subarrays of length 12 (barrel has 3 and endcap 14 layers)
  int nBarrelLayers = 3, nEndcapLayers = 14;
  //each layer has 3 parameters (function 2nd order), so a subarray for each layer has 3 parameters
  int nParametersPerLayer = 3;
  //this subarray for every layer exits for HT/LT hits, so 6 parameters
  int nHTConfigurations = 2;
  //this subarray exists for shared/non-shared hits, so 12 parameters
  int nSharedConfigurations = 2;
  int num =
    layer * nParametersPerLayer +
    isHT * ((abs(HitPart) - 1) * (nEndcapLayers - nBarrelLayers) *
              nParametersPerLayer +
            nBarrelLayers * nParametersPerLayer) +
    isShared * ((abs(HitPart) - 1) * (nEndcapLayers - nBarrelLayers) *
                  nParametersPerLayer * nHTConfigurations +
                nBarrelLayers * nParametersPerLayer * nHTConfigurations) +
    (abs(HitPart) - 1) * nParametersPerLayer * nBarrelLayers *
      nHTConfigurations * nSharedConfigurations;
  //number for that given hit for non-shared conditions
  int num_flat = layer * 3 +
                 isHT * ((abs(HitPart) - 1) * (nEndcapLayers - nBarrelLayers) *
                           nParametersPerLayer +
                         nBarrelLayers * nParametersPerLayer) +
                 (abs(HitPart) - 1) * nParametersPerLayer * nBarrelLayers *
                   nHTConfigurations * nSharedConfigurations;
 
  p0 = dEdxCorrection->hitOccPar[num];
  p1 = dEdxCorrection->hitOccPar[num+1];
  p2 = dEdxCorrection->hitOccPar[num+2];
  p0_flat = dEdxCorrection->hitOccPar[num_flat];
 
  //fitting function is a polynomial 2nd order f(x)=a+b*x+x^2
  //Hence the tot value is divided by the value of the function
  //multiplied to the non-shared intercept
  valToT = p0_flat/(p0+p1*localOccupancy+p2*localOccupancy*localOccupancy);
 
  return ToTmip*valToT;
}
 
double
TRT_ToT_dEdx::trackOccupancyCorrection(const EventContext& ctx,
                                       const Trk::Track* track,
                                       bool useHitsHT,
                                       std::optional<float> localOccupancy) const
{
  SG::ReadCondHandle<TRTDedxcorrection> readHandle{m_ReadKey,ctx};
  const TRTDedxcorrection* dEdxCorrection{*readHandle};
 
  double corr=-999.;
 
  double trackOcc = localOccupancy != std::nullopt
                     ? *localOccupancy
                     : m_localOccTool->LocalOccupancy(ctx, *track);
  const Trk::TrackParameters* perigee = track->perigeeParameters();
  const AmgVector(Trk::TrackParameters::dim)& parameterVector = perigee->parameters();
  double theta = parameterVector[Trk::theta];
  double trackEta = -log(tan(theta/2.0));
 
  // the correction constants were determined in 100 bins of 0.04 in the eta range between -2 and 2
  int index = int(25*(trackEta+2.)); // determine the bin of the corrections
  if (index < 0) index = 0;          // lower bound corresponding to eta = -2
  else if (index > 99) index = 99;   // upper bound corresponding to eta = +2
 
  //Function of the from f(x)=a+b*x+c*x^2 was used as a fitting function, separately for tracks with and without excluding HT hits
  if (useHitsHT) {
    corr=dEdxCorrection->trackOccPar0[index]+dEdxCorrection->trackOccPar1[index]*trackOcc+dEdxCorrection->trackOccPar2[index]*pow(trackOcc,2);
  } else {
    corr=dEdxCorrection->trackOccPar0NoHt[index]+dEdxCorrection->trackOccPar1NoHt[index]*trackOcc+dEdxCorrection->trackOccPar2NoHt[index]*pow(trackOcc,2);
  }
 
  if (corr != 0) {
    return 1./corr;
  }
  return 0.;
}
 
double TRT_ToT_dEdx::calculateTrackLengthInStraw(const Trk::TrackStateOnSurface* trackState, const TRT_ID* identifier) {
  if (trackState->type(Trk::TrackStateOnSurface::Outlier)) return 0.; //Outliers
 
  const Trk::MeasurementBase* trkM = trackState->measurementOnTrack();
  if (!trkM)  {
    return 0.;
  }
 
  // Check if this is RIO on track
  // and if yes check if is TRT Drift Circle
  // then set the ptr
  const InDet::TRT_DriftCircleOnTrack* driftcircle = nullptr;
  if (trkM->type(Trk::MeasurementBaseType::RIO_OnTrack)) {
    const Trk::RIO_OnTrack* tmpRio = static_cast<const Trk::RIO_OnTrack*>(trkM);
    if (tmpRio->rioType(Trk::RIO_OnTrackType::TRT_DriftCircle)) {
      driftcircle = static_cast<const InDet::TRT_DriftCircleOnTrack*>(tmpRio);
    }
  }
 
  if (!driftcircle) {
    return 0.;
  }
 
  const Trk::TrackParameters* trkP = trackState->trackParameters();
  if(trkP==nullptr) return 0.;
 
  double Trt_Rtrack = std::abs(trkP->parameters()[Trk::locR]);
  double Trt_HitTheta = trkP->parameters()[Trk::theta];
  double Trt_HitPhi = trkP->parameters()[Trk::phi];
  Identifier DCId = driftcircle->identify();
  int HitPart = std::abs(identifier->barrel_ec(DCId));
  const InDetDD::TRT_BaseElement* element = driftcircle->detectorElement();
  double strawphi = element->center(DCId).phi();
 
  // check if track is an outlier
  if (Trt_Rtrack >= 2.0) {
    return 0.;
  }
 
  double length=0;
  if (HitPart == 1) { //Barrel
    length = 2*std::sqrt(4-Trt_Rtrack*Trt_Rtrack)*1./std::abs(std::sin(Trt_HitTheta));
  } else if (HitPart == 2) { //EndCap
    length = 2*std::sqrt(4-Trt_Rtrack*Trt_Rtrack)*1./std::sqrt(1-std::sin(Trt_HitTheta)*std::sin(Trt_HitTheta)*std::cos(Trt_HitPhi-strawphi)*std::cos(Trt_HitPhi-strawphi));
  } else {
    // This should never happen
    throw std::runtime_error("Unknown barrel/endcap identifier: " + std::to_string(HitPart) + ". Must be 1(Barrel) or 2(Endcap)");
  }
 
  return length;
}