/**************************************************************************
- * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
- * *
- * Author: The ALICE Off-line Project. *
- * Contributors are mentioned in the code where appropriate. *
- * *
- * Permission to use, copy, modify and distribute this software and its *
- * documentation strictly for non-commercial purposes is hereby granted *
- * without fee, provided that the above copyright notice appears in all *
- * copies and that both the copyright notice and this permission notice *
- * appear in the supporting documentation. The authors make no claims *
- * about the suitability of this software for any purpose. It is *
- * provided "as is" without express or implied warranty. *
- **************************************************************************/
-
-//-----------------------------------------------------------------
-// Implementation of the TRD PID class
-// Assigns the electron and pion liklihoods for each ESD track.
-// The AliTRDprobdist class is instantiated here.
-// The function MakePID(AliESD *event) calculates the probability
-// of having dedx and the probability of having timbin at a given
-// momentum (mom) and particle type k (0 for e) and (2 for pi)
-// from the precalculated timbin distributions.
-// Prashant Shukla <shukla@pi0.physi.uni-heidelberg.de>
-//-----------------------------------------------------------------
+* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
+* *
+* Author: The ALICE Off-line Project. *
+* Contributors are mentioned in the code where appropriate. *
+* *
+* Permission to use, copy, modify and distribute this software and its *
+* documentation strictly for non-commercial purposes is hereby granted *
+* without fee, provided that the above copyright notice appears in all *
+* copies and that both the copyright notice and this permission notice *
+* appear in the supporting documentation. The authors make no claims *
+* about the suitability of this software for any purpose. It is *
+* provided "as is" without express or implied warranty. *
+**************************************************************************/
-#include "AliTRDpidESD.h"
-#include "AliESD.h"
+/* $Id$ */
+
+////////////////////////////////////////////////////////////////////////////
+// //
+// Implementation of the TRD PID class //
+// //
+// Assigns the electron and pion likelihoods to each ESD track. //
+// The function MakePID(AliESDEvent *event) calculates the probability //
+// of having dedx and a maximum timbin at a given //
+// momentum (mom) and particle type k //
+// from the precalculated distributions. //
+// //
+// Authors : //
+// Prashant Shukla <shukla@pi0.physi.uni-heidelberg.de> (orig. version) //
+// Alex Bercuci (a.bercuci@gsi.de) //
+// //
+////////////////////////////////////////////////////////////////////////////
+
+#include "AliESDEvent.h"
#include "AliESDtrack.h"
-#include "AliTRDprobdist.h"
+#include "AliTracker.h"
+
+#include "AliTRDpidESD.h"
+#include "AliTRDgeometry.h"
+#include "AliTRDcalibDB.h"
+#include "Cal/AliTRDCalPID.h"
ClassImp(AliTRDpidESD)
-//_________________________________________________________________________
-AliTRDpidESD::AliTRDpidESD(Double_t *param)
+Bool_t AliTRDpidESD::fgCheckTrackStatus = kTRUE;
+Bool_t AliTRDpidESD::fgCheckKinkStatus = kFALSE;
+Int_t AliTRDpidESD::fgMinPlane = 0;
+
+//_____________________________________________________________________________
+AliTRDpidESD::AliTRDpidESD()
+ :TObject()
+ ,fTrack(NULL)
{
//
- // The main constructor
+ // Default constructor
//
- fMIP=param[0]; // MIP signal
- fRes=param[1]; // relative resolution
- fRange=param[2]; // PID "range" (in sigmas)
+
}
-Double_t AliTRDpidESD::Bethe(Double_t bg)
+//_____________________________________________________________________________
+AliTRDpidESD::AliTRDpidESD(const AliTRDpidESD &p)
+ :TObject(p)
+ ,fTrack(NULL)
{
//
- // Parametrization of the Bethe-Bloch-curve
- // The parametrization is the same as for the TPC and is taken from Lehrhaus.
- //
-
- // This parameters have been adjusted to averaged values from GEANT
- const Double_t kP1 = 7.17960e-02;
- const Double_t kP2 = 8.54196;
- const Double_t kP3 = 1.38065e-06;
- const Double_t kP4 = 5.30972;
- const Double_t kP5 = 2.83798;
-
- // This parameters have been adjusted to Xe-data found in:
- // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
- //const Double_t kP1 = 0.76176E-1;
- //const Double_t kP2 = 10.632;
- //const Double_t kP3 = 3.17983E-6;
- //const Double_t kP4 = 1.8631;
- //const Double_t kP5 = 1.9479;
-
- // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
- const Double_t kBgMin = 0.8;
- const Double_t kBBMax = 6.83298;
- //const Double_t kBgMin = 0.6;
- //const Double_t kBBMax = 17.2809;
- //const Double_t kBgMin = 0.4;
- //const Double_t kBBMax = 82.0;
-
- if (bg > kBgMin) {
- Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
- Double_t aa = TMath::Power(yy,kP4);
- Double_t bb = TMath::Power((1./bg),kP5);
- bb = TMath::Log(kP3 + bb);
- return ((kP2 - aa - bb)*kP1 / aa);
- }
- else {
- return kBBMax;
- }
+ // AliTRDpidESD copy constructor
+ //
+
+ ((AliTRDpidESD &) p).Copy(*this);
+
+}
+
+//_____________________________________________________________________________
+AliTRDpidESD::~AliTRDpidESD()
+{
+ //
+ // Destructor
+ //
+
+ if(fTrack) delete fTrack;
}
-//_________________________________________________________________________
-Int_t AliTRDpidESD::MakePID(AliESD *event)
+//_____________________________________________________________________________
+AliTRDpidESD &AliTRDpidESD::operator=(const AliTRDpidESD &p)
{
//
- // This function calculates the "detector response" PID probabilities
- //
- // The class AliTRDprobdist contains precalculated prob dis.
- AliTRDprobdist *pd = new AliTRDprobdist();
-
- Int_t ntrk=event->GetNumberOfTracks();
- for (Int_t i=0; i<ntrk; i++) {
- AliESDtrack *t=event->GetTrack(i);
- if ((t->GetStatus()&AliESDtrack::kTRDin)==0)
- if ((t->GetStatus()&AliESDtrack::kTRDout)==0)
- if ((t->GetStatus()&AliESDtrack::kTRDrefit)==0) continue;
- if(t->GetTRDsignal()==0) continue;
- // Int_t ns=AliESDtrack::kSPECIES;
- Int_t ns=AliPID::kSPECIES;
- Double_t p[10];
- Double_t mom=t->GetP();
- Double_t probTotal=0.0;
- for (Int_t j=0; j<ns; j++) {
- p[j]=1.;
- for (Int_t ilayer=0; ilayer <6; ilayer++) {
- Double_t dedx=t->GetTRDsignals(ilayer);
- Int_t timbin=t->GetTRDTimBin(ilayer);
- p[j]*= pd->GetProbability(j,mom,dedx);
- p[j]*= pd->GetProbabilityT(j,mom,timbin);
- p[j]*= 100;
- } // loop over layers
- probTotal+=p[j];
- } //loop over particle species
- // printf(" %f %d %f %f %f \n", mom, timbin, p[0], p[1], p[2]);
- for (Int_t j=0; j<ns; j++) {
- if(probTotal) p[j]/= probTotal;
- else p[j]=1.0;
- } //loop over particle species
+ // Assignment operator
+ //
+
+ if (this != &p) ((AliTRDpidESD &) p).Copy(*this);
+ return *this;
+
+}
+
+//_____________________________________________________________________________
+void AliTRDpidESD::Copy(TObject &p) const
+{
+ //
+ // Copy function
+ //
+
+ ((AliTRDpidESD &) p).fgCheckTrackStatus = fgCheckTrackStatus;
+ ((AliTRDpidESD &) p).fgCheckKinkStatus = fgCheckKinkStatus;
+ ((AliTRDpidESD &) p).fgMinPlane = fgMinPlane;
+ ((AliTRDpidESD &) p).fTrack = NULL;
+
+}
+
+//_____________________________________________________________________________
+Int_t AliTRDpidESD::MakePID(AliESDEvent * const event)
+{
+ //
+ // This function calculates the PID probabilities based on TRD signals
+ //
+ // The method produces probabilities based on the charge
+ // and the position of the maximum time bin in each layer.
+ // The dE/dx information can be used as global charge or 2 to 3
+ // slices. Check AliTRDCalPID and AliTRDCalPIDRefMaker for the actual
+ // implementation.
+ //
+ // Author
+ // Alex Bercuci (A.Bercuci@gsi.de) 2nd May 2007
+ //
+
+ AliTRDcalibDB *calibration = AliTRDcalibDB::Instance();
+ if (!calibration) {
+ AliErrorGeneral("AliTRDpidESD::MakePID()"
+ ,"No access to calibration data");
+ return -1;
+ }
+
+// AliTRDrecoParam *rec = AliTRDReconstructor::RecoParam();
+// if (!rec) {
+// AliErrorGeneral("AliTRDpidESD::MakePID()", "No TRD reco param.");
+// return 0x0;
+// }
+
+ // Retrieve the CDB container class with the probability distributions
+ const AliTRDCalPID *pd = calibration->GetPIDObject(AliTRDpidUtil::kLQ);
+ if (!pd) {
+ AliErrorGeneral("AliTRDpidESD::MakePID()"
+ ,"No access to AliTRDCalPID");
+ return -1;
+ }
+
+ // Loop through all ESD tracks
+ Double_t p[10];
+ AliESDtrack *t = NULL;
+ Float_t dedx[AliTRDCalPID::kNSlicesLQ], dEdx;
+ Int_t timebin;
+ Float_t mom, length;
+ Int_t nPlanePID;
+ for (Int_t i=0; i<event->GetNumberOfTracks(); i++) {
+ t = event->GetTrack(i);
+
+ // Check track
+ if(!CheckTrack(t)) continue;
+
+
+ // Skip tracks which have no TRD signal at all
+ if (t->GetTRDsignal()<1.e-5) continue;
+
+ // Loop over detector layers
+ mom = 0.;
+ length = 0.;
+ nPlanePID = 0;
+ for (Int_t iSpecies = 0; iSpecies < AliPID::kSPECIES; iSpecies++)
+ p[iSpecies] = 1./AliPID::kSPECIES;
+
+ for (Int_t iLayer = 0; iLayer < AliTRDgeometry::kNlayer; iLayer++) {
+ // read data for track segment
+ for(int iSlice=0; iSlice<AliTRDCalPID::kNSlicesLQ; iSlice++)
+ dedx[iSlice] = t->GetTRDslice(iLayer, iSlice);
+ dEdx = t->GetTRDslice(iLayer, -1);
+ timebin = t->GetTRDTimBin(iLayer);
+
+ // check data
+ if ((dEdx <= 0.) || (timebin <= -1.)) continue;
+
+ // retrive kinematic info for this track segment
+ if(!RecalculateTrackSegmentKine(t, iLayer, mom, length)){
+ // information is not fully reliable especialy for length
+ // estimation. To be used in the future.
+ }
+
+ // this track segment has fulfilled all requierments
+ nPlanePID++;
+
+ // Get the probabilities for the different particle species
+ for (Int_t iSpecies = 0; iSpecies < AliPID::kSPECIES; iSpecies++) {
+ p[iSpecies] *= pd->GetProbability(iSpecies, mom, dedx, length, iLayer);
+ //p[iSpecies] *= pd->GetProbabilityT(iSpecies, mom, timebin);
+ }
+ }
+ if(nPlanePID == 0) continue;
+
+ // normalize probabilities
+ Double_t probTotal = 0.;
+ for (Int_t iSpecies = 0; iSpecies < AliPID::kSPECIES; iSpecies++) probTotal += p[iSpecies];
+ if(probTotal <= 0.){
+ AliWarning(Form("The total probability (%e) over all species <= 0 in ESD track %d."
+ , probTotal, i));
+ AliWarning("This may be caused by some error in reference data.");
+ AliWarning("Calculation continues but results might be corrupted.");
+ continue;
+ }
+ for(Int_t iSpecies = 0; iSpecies < AliPID::kSPECIES; iSpecies++) p[iSpecies] /= probTotal;
+
+ // book PID to the track
t->SetTRDpid(p);
- } //loop over tracks
- delete pd;
+ t->SetTRDntracklets(nPlanePID<<3);
+ }
+
return 0;
+
+}
+
+//_____________________________________________________________________________
+Bool_t AliTRDpidESD::CheckTrack(AliESDtrack * const t)
+{
+ //
+ // Check if track is eligible for PID calculations
+ //
+
+ // Check the ESD track status
+ if (fgCheckTrackStatus) {
+ if (((t->GetStatus() & AliESDtrack::kTRDout ) == 0) &&
+ ((t->GetStatus() & AliESDtrack::kTRDrefit) == 0)) return kFALSE;
+ }
+
+ // Check for ESD kink tracks
+ if (fgCheckKinkStatus && (t->GetKinkIndex(0) != 0)) return kFALSE;
+
+ return kTRUE;
+
+}
+
+//_____________________________________________________________________________
+Bool_t AliTRDpidESD::RecalculateTrackSegmentKine(AliESDtrack * const esd
+ , Int_t layer
+ , Float_t &mom
+ , Float_t &length)
+{
+ //
+ // Retrive momentum "mom" and track "length" in TRD chamber from plane
+ // "plan" according to information stored in AliESDtrack "t".
+ //
+ // Origin
+ // Alex Bercuci (A.Bercuci@gsi.de)
+ //
+
+ const Float_t kAmHalfWidth = AliTRDgeometry::AmThick() / 2.;
+ const Float_t kDrWidth = AliTRDgeometry::DrThick();
+ const Float_t kTime0 = AliTRDgeometry::GetTime0(layer);
+
+ // set initial length value to chamber height
+ length = 2 * kAmHalfWidth + kDrWidth;
+
+ // retrive track's outer param
+ const AliExternalTrackParam *op = esd->GetOuterParam();
+ if(!op){
+ mom = esd->GetP();
+ return kFALSE;
+ }
+
+ AliExternalTrackParam *param = NULL;
+ if(!fTrack){
+ fTrack = new AliExternalTrackParam(*op);
+ param = fTrack;
+ } else param = new(fTrack) AliExternalTrackParam(*op);
+
+ // retrive the magnetic field
+ Double_t xyz0[3];
+ op->GetXYZ(xyz0);
+ Float_t field = AliTracker::GetBz(xyz0); // Bz in kG at point xyz0
+ Double_t s, t;
+
+ // propagate to chamber entrance
+ if(!param->PropagateTo(kTime0-kAmHalfWidth-kDrWidth, field)){
+ mom = op->GetP();
+ s = op->GetSnp();
+ t = op->GetTgl();
+ if (s < 1.) length /= TMath::Sqrt((1.-s)*(1.+s) / (1. + t*t));
+ return kFALSE;
+ }
+ mom = param->GetP();
+ s = param->GetSnp();
+ t = param->GetTgl();
+ if (s < 1.) length /= TMath::Sqrt((1.-s)*(1.+s) / (1. + t*t));
+
+ // check if track is crossing tracking sector by propagating to chamber exit- maybe is too much :)
+ Double_t alpha = param->GetAlpha();
+ if(!param->PropagateTo(kTime0+kAmHalfWidth, field)) return kFALSE;
+
+ // mark track segments which are crossing SM boundaries along chamber
+ if(TMath::Abs(alpha-param->GetAlpha())>.01) return kFALSE;
+
+ return kTRUE;
+
}
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