New version of SPD tracklet visualization.
[u/mrichter/AliRoot.git] / ITS / AliITStrackV2.cxx
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006b5f7f 1/**************************************************************************
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. *
6 * *
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 **************************************************************************/
15
ae00569a 16/* $Id$ */
17
66e811e2 18///////////////////////////////////////////////////////////////////////////
006b5f7f 19// Implementation of the ITS track class
20//
21// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
a9a2d814 22// dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
66e811e2 23///////////////////////////////////////////////////////////////////////////
006b5f7f 24#include <TMath.h>
006b5f7f 25
26#include "AliCluster.h"
83d73500 27#include "AliESDtrack.h"
58e536c5 28#include "AliESDVertex.h"
8a84886c 29#include "AliITSReconstructor.h"
006b5f7f 30#include "AliITStrackV2.h"
f7a1cc68 31#include "AliTracker.h"
006b5f7f 32
8602c008 33const Int_t AliITStrackV2::fgkWARN = 5;
34
1aedd96e 35ClassImp(AliITStrackV2)
8676d691 36
e43c066c 37
006b5f7f 38//____________________________________________________________________________
6c94f330 39AliITStrackV2::AliITStrackV2() : AliKalmanTrack(),
22b13da0 40 fdEdx(0),
83d73500 41 fESDtrack(0)
e43c066c 42{
ae00569a 43 for(Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) {fIndex[i]=-1; fModule[i]=-1;}
44 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
e43c066c 45}
46
83d73500 47
22b13da0 48//____________________________________________________________________________
67c3dcbe 49AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c) throw (const Char_t *) :
6c94f330 50 AliKalmanTrack(),
51 fdEdx(t.GetITSsignal()),
52 fESDtrack(&t)
53{
83d73500 54 //------------------------------------------------------------------
67c3dcbe 55 // Conversion ESD track -> ITS track.
56 // If c==kTRUE, create the ITS track out of the constrained params.
83d73500 57 //------------------------------------------------------------------
6c94f330 58 const AliExternalTrackParam *par=&t;
59 if (c) {
6c4ef2ed 60 par=t.GetConstrainedParam();
6c94f330 61 if (!par) throw "AliITStrackV2: conversion failed !\n";
62 }
63 Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance());
64
65 //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
66
83d73500 67 SetLabel(t.GetLabel());
68 SetMass(t.GetMass());
6c94f330 69 SetNumberOfClusters(t.GetITSclusters(fIndex));
006b5f7f 70
83d73500 71 if (t.GetStatus()&AliESDtrack::kTIME) {
72 StartTimeIntegral();
73 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
74 SetIntegratedLength(t.GetIntegratedLength());
75 }
e43c066c 76
68b8060b 77 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
006b5f7f 78}
79
7ac23097 80//____________________________________________________________________________
81void AliITStrackV2::ResetClusters() {
82 //------------------------------------------------------------------
83 // Reset the array of attached clusters.
84 //------------------------------------------------------------------
85 for (Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) fIndex[i]=-1;
86 SetChi2(0.);
87 SetNumberOfClusters(0);
88}
89
09cf9d66 90//____________________________________________________________________________
15dd636f 91void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
09cf9d66 92 // Update track params
83d73500 93 fESDtrack->UpdateTrackParams(this,flags);
ae00569a 94 // copy the module indices
95 for(Int_t i=0;i<12;i++) {
96 // printf(" %d\n",GetModuleIndex(i));
97 fESDtrack->SetITSModuleIndex(i,GetModuleIndex(i));
98 }
09cf9d66 99 // copy the 4 dedx samples
100 Double_t sdedx[4]={0.,0.,0.,0.};
101 for(Int_t i=0; i<4; i++) sdedx[i]=fdEdxSample[i];
102 fESDtrack->SetITSdEdxSamples(sdedx);
83d73500 103}
104
006b5f7f 105//____________________________________________________________________________
6c94f330 106AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
107 AliKalmanTrack(t),
108 fdEdx(t.fdEdx),
109 fESDtrack(t.fESDtrack)
110{
006b5f7f 111 //------------------------------------------------------------------
112 //Copy constructor
113 //------------------------------------------------------------------
ef7253ac 114 Int_t i;
ef7253ac 115 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
ae00569a 116 for (i=0; i<2*AliITSgeomTGeo::GetNLayers(); i++) {
117 fIndex[i]=t.fIndex[i];
118 fModule[i]=t.fModule[i];
119 }
006b5f7f 120}
a9a2d814 121
006b5f7f 122//_____________________________________________________________________________
123Int_t AliITStrackV2::Compare(const TObject *o) const {
124 //-----------------------------------------------------------------
125 // This function compares tracks according to the their curvature
126 //-----------------------------------------------------------------
7f6ddf58 127 AliITStrackV2 *t=(AliITStrackV2*)o;
6c23ffed 128 //Double_t co=OneOverPt();
129 //Double_t c =OneOverPt();
15dd636f 130 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
131 Double_t c =GetSigmaY2()*GetSigmaZ2();
006b5f7f 132 if (c>co) return 1;
133 else if (c<co) return -1;
134 return 0;
135}
136
006b5f7f 137//____________________________________________________________________________
6c94f330 138Bool_t
139AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
140{
006b5f7f 141 //------------------------------------------------------------------
142 //This function propagates a track to the minimal distance from the origin
6c94f330 143 //------------------------------------------------------------------
144 Double_t bz=GetBz();
e50912db 145 if (PropagateToDCA(v,bz,kVeryBig)) {
146 Double_t xOverX0,xTimesRho;
147 xOverX0 = d; xTimesRho = d*x0;
148 if (CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kTRUE;
149 }
6c94f330 150 return kFALSE;
006b5f7f 151}
152
153//____________________________________________________________________________
6c94f330 154Bool_t AliITStrackV2::
e50912db 155GetGlobalXYZat(Double_t xloc, Double_t &x, Double_t &y, Double_t &z) const {
006b5f7f 156 //------------------------------------------------------------------
157 //This function returns a track position in the global system
158 //------------------------------------------------------------------
6c94f330 159 Double_t r[3];
f7a1cc68 160 Bool_t rc=GetXYZAt(xloc, GetBz(), r);
6c94f330 161 x=r[0]; y=r[1]; z=r[2];
162 return rc;
006b5f7f 163}
164
165//_____________________________________________________________________________
6c94f330 166Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
006b5f7f 167 //-----------------------------------------------------------------
168 // This function calculates a predicted chi2 increment.
169 //-----------------------------------------------------------------
6c94f330 170 Double_t p[2]={c->GetY(), c->GetZ()};
171 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
172 return AliExternalTrackParam::GetPredictedChi2(p,cov);
a9a2d814 173}
174
175//____________________________________________________________________________
6c94f330 176Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
006b5f7f 177 //------------------------------------------------------------------
178 //This function propagates a track
179 //------------------------------------------------------------------
afd25725 180
6c94f330 181 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
006b5f7f 182
6c94f330 183 Double_t bz=GetBz();
184 if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
e50912db 185 Double_t xOverX0,xTimesRho;
186 xOverX0 = d; xTimesRho = d*x0;
187 if (!CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kFALSE;
006b5f7f 188
dd44614b 189 Double_t x=GetX(), y=GetY(), z=GetZ();
6c94f330 190 if (IsStartedTimeIntegral() && x>oldX) {
191 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
f29dbb4b 192 AddTimeStep(TMath::Sqrt(l2));
193 }
f29dbb4b 194
6c94f330 195 return kTRUE;
006b5f7f 196}
197
198//____________________________________________________________________________
db355ee7 199Bool_t AliITStrackV2::PropagateToTGeo(Double_t xToGo, Int_t nstep, Double_t &xOverX0, Double_t &xTimesRho, Bool_t addTime) {
afd25725 200 //-------------------------------------------------------------------
201 // Propagates the track to a reference plane x=xToGo in n steps.
202 // These n steps are only used to take into account the curvature.
203 // The material is calculated with TGeo. (L.Gaudichet)
204 //-------------------------------------------------------------------
205
206 Double_t startx = GetX(), starty = GetY(), startz = GetZ();
207 Double_t sign = (startx<xToGo) ? -1.:1.;
208 Double_t step = (xToGo-startx)/TMath::Abs(nstep);
209
210 Double_t start[3], end[3], mparam[7], bz = GetBz();
211 Double_t x = startx;
212
213 for (Int_t i=0; i<nstep; i++) {
214
215 GetXYZ(start); //starting global position
216 x += step;
217 if (!GetXYZAt(x, bz, end)) return kFALSE;
218 if (!AliExternalTrackParam::PropagateTo(x, bz)) return kFALSE;
219 AliTracker::MeanMaterialBudget(start, end, mparam);
8fc9f3dc 220 xTimesRho = sign*mparam[4]*mparam[0];
221 xOverX0 = mparam[1];
afd25725 222 if (mparam[1]<900000) {
afd25725 223 if (!AliExternalTrackParam::CorrectForMeanMaterial(xOverX0,
8fc9f3dc 224 xTimesRho,GetMass())) return kFALSE;
225 } else { // this happens when MeanMaterialBudget cannot cross a boundary
226 return kFALSE;
afd25725 227 }
228 }
229
db355ee7 230 if (addTime && IsStartedTimeIntegral() && GetX()>startx) {
afd25725 231 Double_t l2 = ( (GetX()-startx)*(GetX()-startx) +
232 (GetY()-starty)*(GetY()-starty) +
233 (GetZ()-startz)*(GetZ()-startz) );
234 AddTimeStep(TMath::Sqrt(l2));
235 }
236
237 return kTRUE;
238}
239
240//____________________________________________________________________________
6c94f330 241Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
242{
006b5f7f 243 //------------------------------------------------------------------
244 //This function updates track parameters
245 //------------------------------------------------------------------
6c94f330 246 Double_t p[2]={c->GetY(), c->GetZ()};
d9ead1a0 247 Double_t cov[3]={c->GetSigmaY2(), c->GetSigmaYZ(), c->GetSigmaZ2()};
006b5f7f 248
6c94f330 249 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
006b5f7f 250
28d5b13d 251 Int_t n=GetNumberOfClusters();
006b5f7f 252 if (!Invariant()) {
28d5b13d 253 if (n>fgkWARN) AliWarning("Wrong invariant !");
6c94f330 254 return kFALSE;
006b5f7f 255 }
256
6c94f330 257 if (chi2<0) return kTRUE;
67c3dcbe 258
b5205c90 259 // fill residuals for ITS+TPC tracks
badb951a 260 if (fESDtrack) {
261 if (fESDtrack->GetStatus()&AliESDtrack::kTPCin) {
262 AliTracker::FillResiduals(this,p,cov,c->GetVolumeId());
263 }
b5205c90 264 }
150f264c 265
006b5f7f 266 fIndex[n]=index;
267 SetNumberOfClusters(n+1);
268 SetChi2(GetChi2()+chi2);
269
6c94f330 270 return kTRUE;
006b5f7f 271}
272
6c94f330 273Bool_t AliITStrackV2::Invariant() const {
006b5f7f 274 //------------------------------------------------------------------
275 // This function is for debugging purpose only
276 //------------------------------------------------------------------
7f6ddf58 277 Int_t n=GetNumberOfClusters();
6c94f330 278
8a84886c 279 // take into account the misalignment error
280 Float_t maxMisalErrY2=0,maxMisalErrZ2=0;
281 for (Int_t lay=0; lay<AliITSgeomTGeo::kNLayers; lay++) {
d9ead1a0 282 maxMisalErrY2 = TMath::Max(maxMisalErrY2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorY(lay,GetBz()));
283 maxMisalErrZ2 = TMath::Max(maxMisalErrZ2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorZ(lay,GetBz()));
8a84886c 284 }
285 maxMisalErrY2 *= maxMisalErrY2;
286 maxMisalErrZ2 *= maxMisalErrZ2;
287 // this is because when we reset before refitting, we multiply the
288 // matrix by 10
289 maxMisalErrY2 *= 10.;
290 maxMisalErrZ2 *= 10.;
291
6c94f330 292 Double_t sP2=GetParameter()[2];
293 if (TMath::Abs(sP2) >= kAlmost1){
8602c008 294 if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2);
6c94f330 295 return kFALSE;
a9a2d814 296 }
6c94f330 297 Double_t sC00=GetCovariance()[0];
8a84886c 298 if (sC00<=0 || sC00>(9.+maxMisalErrY2)) {
8602c008 299 if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00);
6c94f330 300 return kFALSE;
a9a2d814 301 }
6c94f330 302 Double_t sC11=GetCovariance()[2];
8a84886c 303 if (sC11<=0 || sC11>(9.+maxMisalErrZ2)) {
8602c008 304 if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11);
6c94f330 305 return kFALSE;
a9a2d814 306 }
6c94f330 307 Double_t sC22=GetCovariance()[5];
308 if (sC22<=0 || sC22>1.) {
8602c008 309 if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22);
6c94f330 310 return kFALSE;
a9a2d814 311 }
6c94f330 312 Double_t sC33=GetCovariance()[9];
313 if (sC33<=0 || sC33>1.) {
8602c008 314 if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33);
6c94f330 315 return kFALSE;
a9a2d814 316 }
6c94f330 317 Double_t sC44=GetCovariance()[14];
318 if (sC44<=0 /*|| sC44>6e-5*/) {
8602c008 319 if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44);
6c94f330 320 return kFALSE;
14825d5a 321 }
6c94f330 322
323 return kTRUE;
006b5f7f 324}
325
326//____________________________________________________________________________
6c94f330 327Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
006b5f7f 328 //------------------------------------------------------------------
329 //This function propagates a track
330 //------------------------------------------------------------------
6c94f330 331 Double_t bz=GetBz();
332 if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
006b5f7f 333
006b5f7f 334 if (!Invariant()) {
8a84886c 335 Int_t n=GetNumberOfClusters();
336 if (n>fgkWARN) AliWarning("Wrong invariant !");
337 return kFALSE;
791f9a2a 338 }
339
6c94f330 340 return kTRUE;
a9a2d814 341}
006b5f7f 342
afd25725 343Bool_t AliITStrackV2::MeanBudgetToPrimVertex(Double_t xyz[3], Double_t step, Double_t &d) const {
344
345 //-------------------------------------------------------------------
346 // Get the mean material budget between the actual point and the
347 // primary vertex. (L.Gaudichet)
348 //-------------------------------------------------------------------
349
350 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
351 Double_t vertexX = xyz[0]*cs + xyz[1]*sn;
352
353 Int_t nstep = Int_t((GetX()-vertexX)/step);
354 if (nstep<1) nstep = 1;
355 step = (GetX()-vertexX)/nstep;
356
c7719399 357 // Double_t mparam[7], densMean=0, radLength=0, length=0;
358 Double_t mparam[7];
afd25725 359 Double_t p1[3], p2[3], x = GetX(), bz = GetBz();
360 GetXYZ(p1);
361
362 d=0.;
363
364 for (Int_t i=0; i<nstep; i++) {
365 x += step;
366 if (!GetXYZAt(x, bz, p2)) return kFALSE;
367 AliTracker::MeanMaterialBudget(p1, p2, mparam);
368 if (mparam[1]>900000) return kFALSE;
369 d += mparam[1];
370
371 p1[0] = p2[0];
372 p1[1] = p2[1];
373 p1[2] = p2[2];
374 }
375
376 return kTRUE;
377}
378
6c94f330 379Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
babd135a 380 //------------------------------------------------------------------
6c94f330 381 //This function improves angular track parameters
babd135a 382 //------------------------------------------------------------------
6c94f330 383 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
384//Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
385 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
386 Double_t zv = xyz[2]; // local frame
babd135a 387
6c94f330 388 Double_t dy = Par(0) - yv, dz = Par(1) - zv;
389 Double_t r2=GetX()*GetX() + dy*dy;
6c23ffed 390 Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt());
a9a2d814 391 Double_t beta2=p2/(p2 + GetMass()*GetMass());
392 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
8676d691 393 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
394 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
6c94f330 395
396 Double_t cnv=GetBz()*kB2C;
a9a2d814 397 {
6c94f330 398 Double_t dummy = 4/r2 - GetC()*GetC();
399 if (dummy < 0) return kFALSE;
400 Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy));
401 Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
402 sigma2p += Cov(0)/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
403 sigma2p += ers[1]*ers[1]/r2;
404 sigma2p += 0.25*Cov(14)*cnv*cnv*GetX()*GetX();
00709873 405 Double_t eps2p=sigma2p/(Cov(5) + sigma2p);
6c94f330 406 Par(0) += Cov(3)/(Cov(5) + sigma2p)*(parp - GetSnp());
407 Par(2) = eps2p*GetSnp() + (1 - eps2p)*parp;
408 Cov(5) *= eps2p;
409 Cov(3) *= eps2p;
a9a2d814 410 }
411 {
6c94f330 412 Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2));
413 Double_t sigma2l=theta2;
414 sigma2l += Cov(2)/r2 + Cov(0)*dy*dy*dz*dz/(r2*r2*r2);
415 sigma2l += ers[2]*ers[2]/r2;
416 Double_t eps2l = sigma2l/(Cov(9) + sigma2l);
417 Par(1) += Cov(7 )/(Cov(9) + sigma2l)*(parl - Par(3));
418 Par(4) += Cov(13)/(Cov(9) + sigma2l)*(parl - Par(3));
419 Par(3) = eps2l*Par(3) + (1-eps2l)*parl;
420 Cov(9) *= eps2l;
00709873 421 Cov(13)*= eps2l;
6c94f330 422 Cov(7) *= eps2l;
a9a2d814 423 }
6c94f330 424 if (!Invariant()) return kFALSE;
14825d5a 425
6c94f330 426 return kTRUE;
14825d5a 427}
23efe5f1 428
429void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
430 //-----------------------------------------------------------------
a9a2d814 431 // This function calculates dE/dX within the "low" and "up" cuts.
432 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
09cf9d66 433 // Updated: F. Prino 8-June-2009
23efe5f1 434 //-----------------------------------------------------------------
09cf9d66 435 // The cluster order is: SDD-1, SDD-2, SSD-1, SSD-2
c0dd5278 436
c0dd5278 437 Int_t nc=0;
09cf9d66 438 Float_t dedx[4];
439 for (Int_t il=0; il<4; il++) { // count good (>0) dE/dx values
440 if(fdEdxSample[il]>0.){
441 dedx[nc]= fdEdxSample[il];
442 nc++;
443 }
444 }
445 if(nc<1){
446 SetdEdx(0.);
447 return;
c0dd5278 448 }
23efe5f1 449
09cf9d66 450 Int_t swap; // sort in ascending order
23efe5f1 451 do {
452 swap=0;
09cf9d66 453 for (Int_t i=0; i<nc-1; i++) {
454 if (dedx[i]<=dedx[i+1]) continue;
455 Float_t tmp=dedx[i];
456 dedx[i]=dedx[i+1];
457 dedx[i+1]=tmp;
23efe5f1 458 swap++;
459 }
460 } while (swap);
461
23efe5f1 462
09cf9d66 463 Double_t nl=low*nc, nu =up*nc;
464 Float_t sumamp = 0;
465 Float_t sumweight =0;
466 for (Int_t i=0; i<nc; i++) {
467 Float_t weight =1;
468 if (i<nl+0.1) weight = TMath::Max(1.-(nl-i),0.);
469 if (i>nu-1) weight = TMath::Max(nu-i,0.);
470 sumamp+= dedx[i]*weight;
471 sumweight+=weight;
472 }
473 SetdEdx(sumamp/sumweight);
23efe5f1 474}
c7bafca9 475
8602c008 476//____________________________________________________________________________
477Bool_t AliITStrackV2::
e50912db 478GetPhiZat(Double_t r, Double_t &phi, Double_t &z) const {
479 //------------------------------------------------------------------
480 // This function returns the global cylindrical (phi,z) of the track
481 // position estimated at the radius r.
482 // The track curvature is neglected.
483 //------------------------------------------------------------------
484 Double_t d=GetD(0.,0.);
bc02d571 485 if (TMath::Abs(d) > r) {
486 if (r>1e-1) return kFALSE;
487 r = TMath::Abs(d);
488 }
e50912db 489
490 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
494a930c 491 if (TMath::Abs(d) > rcurr) return kFALSE;
492 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
493 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
e50912db 494
2089d338 495 if (GetX()>=0.) {
496 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
497 } else {
498 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
499 }
500
494a930c 501 // return a phi in [0,2pi[
502 if (phi<0.) phi+=2.*TMath::Pi();
503 else if (phi>=2.*TMath::Pi()) phi-=2.*TMath::Pi();
c7de5c65 504 z=GetZ()+GetTgl()*(TMath::Sqrt((r-d)*(r+d))-TMath::Sqrt((rcurr-d)*(rcurr+d)));
e50912db 505 return kTRUE;
506}
507//____________________________________________________________________________
508Bool_t AliITStrackV2::
509GetLocalXat(Double_t r,Double_t &xloc) const {
8602c008 510 //------------------------------------------------------------------
e50912db 511 // This function returns the local x of the track
512 // position estimated at the radius r.
8602c008 513 // The track curvature is neglected.
514 //------------------------------------------------------------------
515 Double_t d=GetD(0.,0.);
6a14afad 516 if (TMath::Abs(d) > r) {
517 if (r>1e-1) return kFALSE;
518 r = TMath::Abs(d);
519 }
8602c008 520
e50912db 521 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
494a930c 522 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
523 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
2089d338 524 Double_t phi;
525 if (GetX()>=0.) {
526 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
527 } else {
528 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
529 }
8602c008 530
e50912db 531 xloc=r*(TMath::Cos(phi)*TMath::Cos(GetAlpha())
532 +TMath::Sin(phi)*TMath::Sin(GetAlpha()));
8602c008 533
534 return kTRUE;
535}