1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
18 //-----------------------------------------------------------------
19 // Implementation of the TPC track class
20 // This class is used by the AliTPCtracker class
21 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
22 //-----------------------------------------------------------------
24 #include <Riostream.h>
26 #include "AliTPCtrack.h"
27 #include "AliCluster.h"
28 #include "AliTracker.h"
29 #include "AliESDtrack.h"
33 //_________________________________________________________________________
34 AliTPCtrack::AliTPCtrack():
48 //-------------------------------------------------
49 // default constructor
50 //-------------------------------------------------
51 for (Int_t i=0; i<kMaxRow;i++) fIndex[i]=-2;
52 for (Int_t i=0; i<4;i++) fPoints[i]=0.;
53 for (Int_t i=0; i<12;i++) fKinkPoint[i]=0.;
54 for (Int_t i=0; i<3;i++) fKinkIndexes[i]=0;
55 for (Int_t i=0; i<3;i++) fV0Indexes[i]=0;
58 //_________________________________________________________________________
62 AliTPCtrack::AliTPCtrack(Double_t x, Double_t alpha, const Double_t p[5],
63 const Double_t cov[15], Int_t index) :
77 //-----------------------------------------------------------------
78 // This is the main track constructor.
79 //-----------------------------------------------------------------
80 Double_t cnv=1./(AliTracker::GetBz()*kB2C);
90 Double_t c22 = x*x*cov[14] - 2*x*cov[12] + cov[5];
91 Double_t c32 = x*cov[13] - cov[8];
92 Double_t c20 = x*cov[10] - cov[3],
93 c21 = x*cov[11] - cov[4], c42 = x*cov[14] - cov[12];
99 cov[6 ], cov[7 ], c32, cov[9 ],
100 cov[10]*cnv, cov[11]*cnv, c42*cnv, cov[13]*cnv, cov[14]*cnv*cnv
103 Double_t mostProbablePt=AliExternalTrackParam::GetMostProbablePt();
104 Double_t p0=TMath::Sign(1/mostProbablePt,pp[4]);
105 Double_t w0=cc[14]/(cc[14] + p0*p0), w1=p0*p0/(cc[14] + p0*p0);
106 pp[4] = w0*p0 + w1*pp[4];
107 cc[10]*=w1; cc[11]*=w1; cc[12]*=w1; cc[13]*=w1; cc[14]*=w1;
111 SetNumberOfClusters(1);
114 for (Int_t i=1; i<kMaxRow;i++) fIndex[i]=-2;
115 for (Int_t i=0; i<4;i++) fPoints[i]=0.;
116 for (Int_t i=0; i<12;i++) fKinkPoint[i]=0.;
117 for (Int_t i=0; i<3;i++) fKinkIndexes[i]=0;
118 for (Int_t i=0; i<3;i++) fV0Indexes[i]=0;
121 //_____________________________________________________________________________
122 AliTPCtrack::AliTPCtrack(const AliESDtrack& t) :
124 fdEdx(t.GetTPCsignal()),
136 //-----------------------------------------------------------------
137 // Conversion AliESDtrack -> AliTPCtrack.
138 //-----------------------------------------------------------------
139 SetNumberOfClusters(t.GetTPCclusters(fIndex));
140 SetLabel(t.GetLabel());
141 SetMass(t.GetMass());
142 for (Int_t i=0; i<4;i++) fPoints[i]=0.;
143 for (Int_t i=0; i<12;i++) fKinkPoint[i]=0.;
144 for (Int_t i=0; i<3;i++) fKinkIndexes[i]=0;
145 for (Int_t i=0; i<3;i++) fV0Indexes[i]=0;
147 Set(t.GetX(),t.GetAlpha(),t.GetParameter(),t.GetCovariance());
149 if ((t.GetStatus()&AliESDtrack::kTIME) == 0) return;
151 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
152 SetIntegratedLength(t.GetIntegratedLength());
155 //_____________________________________________________________________________
156 AliTPCtrack::AliTPCtrack(const AliTPCtrack& t) :
160 fNFoundable(t.fNFoundable),
161 fBConstrain(t.fBConstrain),
162 fLastPoint(t.fLastPoint),
163 fFirstPoint(t.fFirstPoint),
164 fRemoval(t.fRemoval),
165 fTrackType(t.fTrackType),
167 fNShared(t.fNShared),
168 fReference(t.fReference)
171 //-----------------------------------------------------------------
172 // This is a track copy constructor.
173 //-----------------------------------------------------------------
174 Set(t.GetX(),t.GetAlpha(),t.GetParameter(),t.GetCovariance());
176 for (Int_t i=0; i<kMaxRow; i++) fIndex[i]=t.fIndex[i];
177 for (Int_t i=0; i<4;i++) fPoints[i]=t.fPoints[i];
178 for (Int_t i=0; i<12;i++) fKinkPoint[i]=t.fKinkPoint[i];
179 for (Int_t i=0; i<3;i++) fKinkIndexes[i]=t.fKinkIndexes[i];
180 for (Int_t i=0; i<3;i++) fV0Indexes[i]=t.fV0Indexes[i];
183 AliTPCtrack& AliTPCtrack::operator=(const AliTPCtrack& o){
185 AliKalmanTrack::operator=(o);
187 for(Int_t i = 0;i<kMaxRow;++i)fIndex[i] = o.fIndex[i];
188 for(Int_t i = 0;i<4;++i)fPoints[i] = o.fPoints[i];
190 fNFoundable = o.fNFoundable;
191 fBConstrain = o.fBConstrain;
192 fLastPoint = o.fLastPoint;
193 fFirstPoint = o.fFirstPoint;
194 fTrackType = o.fTrackType;
196 fNShared = o.fNShared;
197 fReference = o.fReference;
198 for(Int_t i = 0;i<12;++i) fKinkPoint[i] = o.fKinkPoint[i];
200 for(Int_t i = 0;i<3;++i){
201 fKinkIndexes[i] = o.fKinkIndexes[i];
202 fV0Indexes[i] = o.fV0Indexes[i];
210 //_____________________________________________________________________________
211 Int_t AliTPCtrack::Compare(const TObject *o) const {
212 //-----------------------------------------------------------------
213 // This function compares tracks according to the their curvature
214 //-----------------------------------------------------------------
215 AliTPCtrack *t=(AliTPCtrack*)o;
216 //Double_t co=t->OneOverPt();
217 //Double_t c = OneOverPt();
218 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
219 Double_t c =GetSigmaY2()*GetSigmaZ2();
221 else if (c<co) return -1;
225 Double_t AliTPCtrack::GetPredictedChi2(const AliCluster *c) const {
226 //-----------------------------------------------------------------
227 // This function calculates a predicted chi2 increment.
228 //-----------------------------------------------------------------
229 Double_t p[2]={c->GetY(), c->GetZ()};
230 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
231 return AliExternalTrackParam::GetPredictedChi2(p,cov);
234 //_____________________________________________________________________________
235 Bool_t AliTPCtrack::PropagateTo(Double_t xk,Double_t rho,Double_t x0) {
236 //-----------------------------------------------------------------
237 // This function propagates a track to a reference plane x=xk.
238 // rho - density of the crossed matrial (g/cm^3)
239 // x0 - radiation length of the crossed material (g/cm^2)
240 //-----------------------------------------------------------------
241 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
244 if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
246 Double_t d = TMath::Sqrt((GetX()-oldX)*(GetX()-oldX) +
247 (GetY()-oldY)*(GetY()-oldY) +
248 (GetZ()-oldZ)*(GetZ()-oldZ));
249 if (IsStartedTimeIntegral() && GetX()>oldX) AddTimeStep(d);
251 if (oldX < xk) d = -d;
252 if (!AliExternalTrackParam::CorrectForMaterial(d*rho/x0,x0,GetMass()))
258 //_____________________________________________________________________________
260 AliTPCtrack::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
262 //-----------------------------------------------------------------
263 // This function propagates tracks to the vertex.
264 //-----------------------------------------------------------------
266 if (PropagateToDCA(v,bz,kVeryBig))
267 if (AliExternalTrackParam::CorrectForMaterial(d,x0,GetMass())) return kTRUE;
271 //_____________________________________________________________________________
272 Bool_t AliTPCtrack::Update(const AliCluster *c, Double_t chisq, Int_t index) {
273 //-----------------------------------------------------------------
274 // This function associates a cluster with this track.
275 //-----------------------------------------------------------------
276 Double_t p[2]={c->GetY(), c->GetZ()};
277 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
279 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
281 AliTracker::FillResiduals(this,p,cov,c->GetVolumeId());
283 Int_t n=GetNumberOfClusters();
285 SetNumberOfClusters(n+1);
286 SetChi2(GetChi2()+chisq);
291 ////////////////////////////////////////////////////////////////////////
294 Float_t AliTPCtrack::Density(Int_t row0, Int_t row1)
297 // calculate cluster density
300 //if (row0<fFirstPoint) row0 = fFirstPoint;
301 if (row1>fLastPoint) row1 = fLastPoint;
304 for (Int_t i=row0;i<=row1;i++){
305 // Int_t index = fClusterIndex[i];
306 Int_t index = fIndex[i];
307 if (index!=-1) good++;
308 if (index>0) found++;
311 if (good>0) density = Float_t(found)/Float_t(good);
316 Float_t AliTPCtrack::Density2(Int_t row0, Int_t row1)
319 // calculate cluster density
323 for (Int_t i=row0;i<=row1;i++){
324 Int_t index = fIndex[i];
325 if (index!=-1) good++;
326 if (index>0) found++;
329 if (good>0) density = Float_t(found)/Float_t(good);
333 void AliTPCtrack::UpdatePoints()
335 //--------------------------------------------------
336 //calculates first ,amx dens and last points
337 //--------------------------------------------------
338 Float_t density[160];
339 for (Int_t i=0;i<160;i++) density[i]=-1.;
347 for (Int_t i=0;i<160;i++){
348 Int_t last = i-range;
349 if (nall<range) nall++;
351 if (fIndex[last]>0&& (fIndex[last]&0x8000)==0) ngood--;
352 if (fIndex[last]==-1) undeff--;
354 if (fIndex[i]>0&& (fIndex[i]&0x8000)==0) ngood++;
355 if (fIndex[i]==-1) undeff++;
356 if (nall==range &&undeff<range/2) density[i-range/2] = Float_t(ngood)/Float_t(nall-undeff);
360 for (Int_t i=0;i<160;i++){
361 if (density[i]<0) continue;
362 if (density[i]>maxdens){
369 fPoints[3] = maxdens;
370 fPoints[1] = indexmax;
373 for (Int_t i=indexmax;i<160;i++){
374 if (density[i]<0) continue;
375 if (density[i]<maxdens/2.) {
382 for (Int_t i=indexmax;i>0;i--){
383 if (density[i]<0) continue;
384 if (density[i]<maxdens/2.) {
392 Double_t AliTPCtrack::GetBz() const {
394 // returns Bz component of the magnetic field (kG)
396 if (AliTracker::UniformField()) return AliTracker::GetBz();
397 Double_t r[3]; GetXYZ(r);
398 return AliTracker::GetBz(r);