Changes to allow NO spectator signal when specattors are tracked in sim
[u/mrichter/AliRoot.git] / TRD / AliTRDpidESD.cxx
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b0f03c34 1/**************************************************************************
0d83b3a5 2* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3* *
4* Author: The ALICE Off-line Project. *
5* Contributors are mentioned in the code where appropriate. *
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7* Permission to use, copy, modify and distribute this software and its *
8* documentation strictly for non-commercial purposes is hereby granted *
9* without fee, provided that the above copyright notice appears in all *
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11* appear in the supporting documentation. The authors make no claims *
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13* provided "as is" without express or implied warranty. *
14**************************************************************************/
b0f03c34 15
dab811d0 16/* $Id$ */
17
b52cb1b6 18////////////////////////////////////////////////////////////////////////////
19// //
20// Implementation of the TRD PID class //
21// //
22// Assigns the electron and pion likelihoods to each ESD track. //
c8ab4518 23// The function MakePID(AliESDEvent *event) calculates the probability //
b52cb1b6 24// of having dedx and a maximum timbin at a given //
25// momentum (mom) and particle type k //
26// from the precalculated distributions. //
27// //
dab811d0 28// Authors : //
c8ab4518 29// Prashant Shukla <shukla@pi0.physi.uni-heidelberg.de> (orig. version) //
30// Alex Bercuci (a.bercuci@gsi.de) //
b52cb1b6 31// //
32////////////////////////////////////////////////////////////////////////////
b0f03c34 33
b52cb1b6 34#include "AliLog.h"
af885e0f 35#include "AliESDEvent.h"
b0f03c34 36#include "AliESDtrack.h"
c6011b06 37#include "AliTracker.h"
c8ab4518 38#include "AliRun.h"
b52cb1b6 39
40#include "AliTRDpidESD.h"
41#include "AliTRDgeometry.h"
cc7cef99 42#include "AliTRDcalibDB.h"
dab811d0 43#include "AliTRDtrack.h"
720a0a16 44#include "Cal/AliTRDCalPID.h"
b0f03c34 45
46ClassImp(AliTRDpidESD)
47
c8ab4518 48Bool_t AliTRDpidESD::fgCheckTrackStatus = kTRUE;
49Bool_t AliTRDpidESD::fgCheckKinkStatus = kFALSE;
50Int_t AliTRDpidESD::fgMinPlane = 0;
df34b21e 51
b52cb1b6 52//_____________________________________________________________________________
dab811d0 53AliTRDpidESD::AliTRDpidESD()
c8ab4518 54 :TObject()
55 ,fTrack(0x0)
b0f03c34 56{
57 //
b52cb1b6 58 // Default constructor
b0f03c34 59 //
b52cb1b6 60
b0f03c34 61}
62
b52cb1b6 63//_____________________________________________________________________________
dab811d0 64AliTRDpidESD::AliTRDpidESD(const AliTRDpidESD &p)
c8ab4518 65 :TObject(p)
66 ,fTrack(0x0)
eab5961e 67{
b0f03c34 68 //
b52cb1b6 69 // AliTRDpidESD copy constructor
b0f03c34 70 //
eab5961e 71
b52cb1b6 72 ((AliTRDpidESD &) p).Copy(*this);
73
74}
75
76//_____________________________________________________________________________
c6011b06 77AliTRDpidESD::~AliTRDpidESD()
78{
79 //
80 // Destructor
81 //
c8ab4518 82
83 if(fTrack) delete fTrack;
84
c6011b06 85}
86
87//_____________________________________________________________________________
b52cb1b6 88AliTRDpidESD &AliTRDpidESD::operator=(const AliTRDpidESD &p)
89{
90 //
91 // Assignment operator
92 //
93
94 if (this != &p) ((AliTRDpidESD &) p).Copy(*this);
95 return *this;
96
97}
98
99//_____________________________________________________________________________
100void AliTRDpidESD::Copy(TObject &p) const
101{
102 //
103 // Copy function
104 //
105
c8ab4518 106 ((AliTRDpidESD &) p).fgCheckTrackStatus = fgCheckTrackStatus;
107 ((AliTRDpidESD &) p).fgCheckKinkStatus = fgCheckKinkStatus;
108 ((AliTRDpidESD &) p).fgMinPlane = fgMinPlane;
c6011b06 109 ((AliTRDpidESD &) p).fTrack = 0x0;
0d83b3a5 110
b0f03c34 111}
112
b52cb1b6 113//_____________________________________________________________________________
af885e0f 114Int_t AliTRDpidESD::MakePID(AliESDEvent *event)
b0f03c34 115{
116 //
b52cb1b6 117 // This function calculates the PID probabilities based on TRD signals
b0f03c34 118 //
dab811d0 119 // The method produces probabilities based on the charge
120 // and the position of the maximum time bin in each layer.
121 // The dE/dx information can be used as global charge or 2 to 3
720a0a16 122 // slices. Check AliTRDCalPID and AliTRDCalPIDRefMaker for the actual
dab811d0 123 // implementation.
124 //
125 // Author
126 // Alex Bercuci (A.Bercuci@gsi.de) 2nd May 2007
c8ab4518 127 //
dab811d0 128
0d83b3a5 129 AliTRDcalibDB *calibration = AliTRDcalibDB::Instance();
130 if (!calibration) {
131 AliErrorGeneral("AliTRDpidESD::MakePID()"
132 ,"No access to calibration data");
133 return -1;
134 }
135
3a039a31 136// AliTRDrecoParam *rec = AliTRDReconstructor::RecoParam();
137// if (!rec) {
138// AliErrorGeneral("AliTRDpidESD::MakePID()", "No TRD reco param.");
139// return 0x0;
140// }
4ba1d6ae 141
0d83b3a5 142 // Retrieve the CDB container class with the probability distributions
143 const AliTRDCalPID *pd = calibration->GetPIDObject(AliTRDpidUtil::kLQ);
144 if (!pd) {
145 AliErrorGeneral("AliTRDpidESD::MakePID()"
146 ,"No access to AliTRDCalPID");
147 return -1;
148 }
149
150 // Loop through all ESD tracks
151 Double_t p[10];
152 AliESDtrack *t = 0x0;
153 Float_t dedx[AliTRDtrack::kNslice], dEdx;
154 Int_t timebin;
155 Float_t mom, length;
156 Int_t nPlanePID;
157 for (Int_t i=0; i<event->GetNumberOfTracks(); i++) {
158 t = event->GetTrack(i);
159
160 // Check track
161 if(!CheckTrack(t)) continue;
162
163
164 // Skip tracks which have no TRD signal at all
165 if (t->GetTRDsignal() == 0.) continue;
166
167 // Loop over detector layers
168 mom = 0.;
169 length = 0.;
170 nPlanePID = 0;
171 for (Int_t iSpecies = 0; iSpecies < AliPID::kSPECIES; iSpecies++)
c8ab4518 172 p[iSpecies] = 1./AliPID::kSPECIES;
173
0d83b3a5 174 for (Int_t iLayer = 0; iLayer < AliTRDgeometry::kNlayer; iLayer++) {
175 // read data for track segment
176 for(int iSlice=0; iSlice<AliTRDtrack::kNslice; iSlice++)
177 dedx[iSlice] = t->GetTRDslice(iLayer, iSlice);
178 dEdx = t->GetTRDslice(iLayer, -1);
179 timebin = t->GetTRDTimBin(iLayer);
180
181 // check data
182 if ((dEdx <= 0.) || (timebin <= -1.)) continue;
183
184 // retrive kinematic info for this track segment
185 if(!RecalculateTrackSegmentKine(t, iLayer, mom, length)){
186 // information is not fully reliable especialy for length
187 // estimation. To be used in the future.
188 }
189
190 // this track segment has fulfilled all requierments
191 nPlanePID++;
192
193 // Get the probabilities for the different particle species
194 for (Int_t iSpecies = 0; iSpecies < AliPID::kSPECIES; iSpecies++) {
195 p[iSpecies] *= pd->GetProbability(iSpecies, mom, dedx, length, iLayer);
196 //p[iSpecies] *= pd->GetProbabilityT(iSpecies, mom, timebin);
197 }
198 }
199 if(nPlanePID == 0) continue;
200
201 // normalize probabilities
202 Double_t probTotal = 0.;
203 for (Int_t iSpecies = 0; iSpecies < AliPID::kSPECIES; iSpecies++) probTotal += p[iSpecies];
204 if(probTotal <= 0.){
205 AliWarning(Form("The total probability (%e) over all species <= 0 in ESD track %d."
206 , probTotal, i));
207 AliWarning("This may be caused by some error in reference data.");
208 AliWarning("Calculation continues but results might be corrupted.");
209 continue;
210 }
211 for(Int_t iSpecies = 0; iSpecies < AliPID::kSPECIES; iSpecies++) p[iSpecies] /= probTotal;
212
213 // book PID to the track
214 t->SetTRDpid(p);
215 t->SetTRDpidQuality(nPlanePID);
216 }
217
218 return 0;
c8ab4518 219
dab811d0 220}
b52cb1b6 221
dab811d0 222//_____________________________________________________________________________
223Bool_t AliTRDpidESD::CheckTrack(AliESDtrack *t)
224{
225 //
226 // Check if track is eligible for PID calculations
227 //
0d83b3a5 228
229 // Check the ESD track status
230 if (fgCheckTrackStatus) {
231 if (((t->GetStatus() & AliESDtrack::kTRDout ) == 0) &&
232 ((t->GetStatus() & AliESDtrack::kTRDrefit) == 0)) return kFALSE;
233 }
b52cb1b6 234
0d83b3a5 235 // Check for ESD kink tracks
236 if (fgCheckKinkStatus && (t->GetKinkIndex(0) != 0)) return kFALSE;
b52cb1b6 237
0d83b3a5 238 return kTRUE;
c8ab4518 239
dab811d0 240}
b52cb1b6 241
dab811d0 242//_____________________________________________________________________________
c8ab4518 243Bool_t AliTRDpidESD::RecalculateTrackSegmentKine(AliESDtrack *esd
0d83b3a5 244 , Int_t layer
245 , Float_t &mom
246 , Float_t &length)
dab811d0 247{
248 //
249 // Retrive momentum "mom" and track "length" in TRD chamber from plane
250 // "plan" according to information stored in AliESDtrack "t".
c6011b06 251 //
252 // Origin
253 // Alex Bercuci (A.Bercuci@gsi.de)
c8ab4518 254 //
dab811d0 255
0d83b3a5 256 const Float_t kAmHalfWidth = AliTRDgeometry::AmThick() / 2.;
f162af62 257 const Float_t kDrWidth = AliTRDgeometry::DrThick();
0d83b3a5 258 const Float_t kTime0 = AliTRDgeometry::GetTime0(layer);
259
260 // set initial length value to chamber height
261 length = 2 * kAmHalfWidth + kDrWidth;
262
263 // retrive track's outer param
264 const AliExternalTrackParam *op = esd->GetOuterParam();
265 if(!op){
266 mom = esd->GetP();
267 return kFALSE;
268 }
269
270 AliExternalTrackParam *param = 0x0;
271 if(!fTrack){
272 fTrack = new AliExternalTrackParam(*op);
273 param = fTrack;
274 } else param = new(fTrack) AliExternalTrackParam(*op);
275
276 // retrive the magnetic field
277 Double_t xyz0[3];
278 op->GetXYZ(xyz0);
279 Float_t field = AliTracker::GetBz(xyz0); // Bz in kG at point xyz0
280 Double_t s, t;
281
282 // propagate to chamber entrance
283 if(!param->PropagateTo(kTime0-kAmHalfWidth-kDrWidth, field)){
284 mom = op->GetP();
285 s = op->GetSnp();
286 t = op->GetTgl();
287 if (s < 1.) length /= TMath::Sqrt((1. - s*s) / (1. + t*t));
288 return kFALSE;
289 }
290 mom = param->GetP();
291 s = param->GetSnp();
292 t = param->GetTgl();
293 if (s < 1.) length /= TMath::Sqrt((1. - s*s) / (1. + t*t));
294
295 // check if track is crossing tracking sector by propagating to chamber exit- maybe is too much :)
296 Double_t alpha = param->GetAlpha();
297 if(!param->PropagateTo(kTime0+kAmHalfWidth, field)) return kFALSE;
298
299 // mark track segments which are crossing SM boundaries along chamber
300 if(TMath::Abs(alpha-param->GetAlpha())>.01) return kFALSE;
301
302 return kTRUE;
dab811d0 303
c8ab4518 304}