* provided "as is" without express or implied warranty. *
**************************************************************************/
+/* $Id$ */
+
////////////////////////////////////////////////////////////////////////////
// //
// Implementation of the TRD PID class //
// //
// Assigns the electron and pion likelihoods to each ESD track. //
-// The function MakePID(AliESD *event) calculates the probability //
+// 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. //
// //
-// Original version: //
-// Prashant Shukla <shukla@pi0.physi.uni-heidelberg.de> //
+// Authors : //
+// Prashant Shukla <shukla@pi0.physi.uni-heidelberg.de> (orig. version) //
+// Alex Bercuci (a.bercuci@gsi.de) //
// //
////////////////////////////////////////////////////////////////////////////
#include "AliLog.h"
-#include "AliESD.h"
+#include "AliESDEvent.h"
#include "AliESDtrack.h"
+#include "AliTracker.h"
+#include "AliRun.h"
#include "AliTRDpidESD.h"
#include "AliTRDgeometry.h"
#include "AliTRDcalibDB.h"
-#include "Cal/AliTRDCalPIDLQ.h"
+#include "AliTRDtrack.h"
+#include "Cal/AliTRDCalPID.h"
ClassImp(AliTRDpidESD)
+Bool_t AliTRDpidESD::fgCheckTrackStatus = kTRUE;
+Bool_t AliTRDpidESD::fgCheckKinkStatus = kFALSE;
+Int_t AliTRDpidESD::fgMinPlane = 0;
+
//_____________________________________________________________________________
-AliTRDpidESD::AliTRDpidESD():TObject()
+AliTRDpidESD::AliTRDpidESD()
+ :TObject()
+ ,fTrack(0x0)
{
//
// Default constructor
//
- fCheckTrackStatus = kTRUE;
- fCheckKinkStatus = kFALSE;
- fMinPlane = 0;
-
}
//_____________________________________________________________________________
-AliTRDpidESD::AliTRDpidESD(const AliTRDpidESD &p):TObject(p)
+AliTRDpidESD::AliTRDpidESD(const AliTRDpidESD &p)
+ :TObject(p)
+ ,fTrack(0x0)
{
//
// AliTRDpidESD copy constructor
}
+//_____________________________________________________________________________
+AliTRDpidESD::~AliTRDpidESD()
+{
+ //
+ // Destructor
+ //
+
+ if(fTrack) delete fTrack;
+
+}
+
//_____________________________________________________________________________
AliTRDpidESD &AliTRDpidESD::operator=(const AliTRDpidESD &p)
{
// Copy function
//
- ((AliTRDpidESD &) p).fCheckTrackStatus = fCheckTrackStatus;
- ((AliTRDpidESD &) p).fCheckKinkStatus = fCheckKinkStatus;
- ((AliTRDpidESD &) p).fMinPlane = fMinPlane;
-
+ ((AliTRDpidESD &) p).fgCheckTrackStatus = fgCheckTrackStatus;
+ ((AliTRDpidESD &) p).fgCheckKinkStatus = fgCheckKinkStatus;
+ ((AliTRDpidESD &) p).fgMinPlane = fgMinPlane;
+ ((AliTRDpidESD &) p).fTrack = 0x0;
+
}
//_____________________________________________________________________________
-Int_t AliTRDpidESD::MakePID(AliESD *event)
+Int_t AliTRDpidESD::MakePID(AliESDEvent *event)
{
//
// This function calculates the PID probabilities based on TRD signals
//
- // So far this method produces probabilities based on the total charge
- // in each layer and the position of the maximum time bin in each layer.
- // In a final version this should also exploit the charge measurement in
- // the different slices of a given layer.
- //
-
- Double_t p[10];
- Int_t nSpecies = AliPID::kSPECIES;
- Int_t nPlanePID = 0;
- Double_t mom = 0.0;
- Double_t probTotal = 0.0;
-
- AliTRDcalibDB *calibration = AliTRDcalibDB::Instance();
- if (!calibration) {
- //AliError("No access to calibration data\n");
- return -1;
- }
-
- // Retrieve the CDB container class with the probability distributions
- const AliTRDCalPIDLQ *pd = calibration->GetPIDLQObject();
- if (!pd) {
- //AliError("No access to AliTRDCalPIDLQ\n");
- return -1;
- }
-
- // Loop through all ESD tracks
- Int_t ntrk = event->GetNumberOfTracks();
- for (Int_t i = 0; i < ntrk; i++) {
-
- AliESDtrack *t = event->GetTrack(i);
-
- // Check the ESD track status
- if (fCheckTrackStatus) {
- if (((t->GetStatus() & AliESDtrack::kTRDout ) == 0) &&
- ((t->GetStatus() & AliESDtrack::kTRDrefit) == 0)) {
- continue;
- }
- }
-
- // Check for ESD kink tracks
- if (fCheckKinkStatus) {
- if (t->GetKinkIndex(0) != 0) {
- continue;
- }
- }
-
- // Skip tracks that have no TRD signal at all
- if (t->GetTRDsignal() == 0) {
- continue;
- }
-
- mom = t->GetP();
- probTotal = 0.0;
- nPlanePID = 0;
- for (Int_t iSpecies = 0; iSpecies < nSpecies; iSpecies++) {
- p[iSpecies] = 1.0;
- }
-
- // Check the different detector layers
- for (Int_t iPlan = 0; iPlan < AliTRDgeometry::kNplan; iPlan++) {
-
- // Use the total charge in a given plane
- Double_t dedx = t->GetTRDsignals(iPlan,-1);
- Int_t timebin = t->GetTRDTimBin(iPlan);
- if ((dedx > 0.0) &&
- (timebin > -1.0)) {
-
- nPlanePID++;
-
- // Get the probabilities for the different particle species
- for (Int_t iSpecies = 0; iSpecies < nSpecies; iSpecies++) {
-
- p[iSpecies] *= pd->GetProbability(iSpecies,mom,dedx);
- p[iSpecies] *= pd->GetProbabilityT(iSpecies,mom,timebin);
- p[iSpecies] *= 100.0; // ??????????????
-
- probTotal += p[iSpecies];
+ // 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;
+ }
+
+ // Retrieve the CDB container class with the probability distributions
+ const AliTRDCalPID *pd = calibration->GetPIDObject(1);
+ if (!pd) {
+ AliErrorGeneral("AliTRDpidESD::MakePID()"
+ ,"No access to AliTRDCalPID");
+ return -1;
}
- }
+ // Loop through all ESD tracks
+ Double_t p[10];
+ AliESDtrack *t = 0x0;
+ Float_t dedx[AliTRDtrack::kNslice], 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() == 0.) 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 iPlan = 0; iPlan < AliTRDgeometry::kNplan; iPlan++) {
+ // read data for track segment
+ for(int iSlice=0; iSlice<AliTRDtrack::kNslice; iSlice++)
+ dedx[iSlice] = t->GetTRDsignals(iPlan, iSlice);
+ dEdx = t->GetTRDsignals(iPlan, -1);
+ timebin = t->GetTRDTimBin(iPlan);
+
+ // check data
+ if ((dEdx <= 0.) || (timebin <= -1.)) continue;
+
+ // retrive kinematic info for this track segment
+ if(!RecalculateTrackSegmentKine(t, iPlan, 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, iPlan);
+ //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);
+ t->SetTRDpidQuality(nPlanePID);
+ }
+
+ return 0;
- }
+}
- for (Int_t iSpecies = 0; iSpecies < nSpecies; iSpecies++) {
- if ((probTotal > 0.0) &&
- (nPlanePID > fMinPlane)) {
- p[iSpecies] /= probTotal;
- }
- else {
- p[iSpecies] = 1.0;
- }
- }
+//_____________________________________________________________________________
+Bool_t AliTRDpidESD::CheckTrack(AliESDtrack *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;
+
+}
- t->SetTRDpid(p);
+//_____________________________________________________________________________
+Bool_t AliTRDpidESD::RecalculateTrackSegmentKine(AliESDtrack *esd
+ , Int_t plan
+ , 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(plan);
+
+ // 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;
+ }
- return 0;
+ AliExternalTrackParam *param = 0x0;
+ 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*s) / (1. + t*t));
+ return kFALSE;
+ }
+ mom = param->GetP();
+ s = param->GetSnp();
+ t = param->GetTgl();
+ if (s < 1.) length /= TMath::Sqrt((1. - s*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;
}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff