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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 | ||
66e811e2 | 16 | /////////////////////////////////////////////////////////////////////////// |
006b5f7f | 17 | // Implementation of the ITS track class |
18 | // | |
19 | // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch | |
a9a2d814 | 20 | // dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch |
66e811e2 | 21 | /////////////////////////////////////////////////////////////////////////// |
006b5f7f | 22 | #include <TMath.h> |
006b5f7f | 23 | |
24 | #include "AliCluster.h" | |
6c94f330 | 25 | #include "AliTracker.h" |
83d73500 | 26 | #include "AliESDtrack.h" |
006b5f7f | 27 | #include "AliITStrackV2.h" |
28 | ||
8602c008 | 29 | const Int_t AliITStrackV2::fgkWARN = 5; |
30 | ||
1aedd96e | 31 | ClassImp(AliITStrackV2) |
8676d691 | 32 | |
e43c066c | 33 | |
22b13da0 | 34 | //____________________________________________________________________________ |
6c94f330 | 35 | AliITStrackV2::AliITStrackV2() : AliKalmanTrack(), |
22b13da0 | 36 | fdEdx(0), |
83d73500 | 37 | fESDtrack(0) |
e43c066c | 38 | { |
ef7253ac | 39 | for(Int_t i=0; i<2*kMaxLayer; i++) fIndex[i]=-1; |
e43c066c | 40 | for(Int_t i=0; i<4; i++) fdEdxSample[i]=0; |
e43c066c | 41 | } |
42 | ||
83d73500 | 43 | |
83d73500 | 44 | //____________________________________________________________________________ |
67c3dcbe | 45 | AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c) throw (const Char_t *) : |
6c94f330 | 46 | AliKalmanTrack(), |
47 | fdEdx(t.GetITSsignal()), | |
48 | fESDtrack(&t) | |
49 | { | |
83d73500 | 50 | //------------------------------------------------------------------ |
67c3dcbe | 51 | // Conversion ESD track -> ITS track. |
52 | // If c==kTRUE, create the ITS track out of the constrained params. | |
83d73500 | 53 | //------------------------------------------------------------------ |
6c94f330 | 54 | const AliExternalTrackParam *par=&t; |
55 | if (c) { | |
6c4ef2ed | 56 | par=t.GetConstrainedParam(); |
6c94f330 | 57 | if (!par) throw "AliITStrackV2: conversion failed !\n"; |
58 | } | |
59 | Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance()); | |
60 | ||
61 | //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n"; | |
62 | ||
83d73500 | 63 | SetLabel(t.GetLabel()); |
64 | SetMass(t.GetMass()); | |
6c94f330 | 65 | SetNumberOfClusters(t.GetITSclusters(fIndex)); |
006b5f7f | 66 | |
83d73500 | 67 | if (t.GetStatus()&AliESDtrack::kTIME) { |
68 | StartTimeIntegral(); | |
69 | Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times); | |
70 | SetIntegratedLength(t.GetIntegratedLength()); | |
71 | } | |
e43c066c | 72 | |
68b8060b | 73 | for(Int_t i=0; i<4; i++) fdEdxSample[i]=0; |
006b5f7f | 74 | } |
75 | ||
15dd636f | 76 | void AliITStrackV2::UpdateESDtrack(ULong_t flags) const { |
83d73500 | 77 | fESDtrack->UpdateTrackParams(this,flags); |
78 | } | |
79 | ||
006b5f7f | 80 | //____________________________________________________________________________ |
6c94f330 | 81 | AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) : |
82 | AliKalmanTrack(t), | |
83 | fdEdx(t.fdEdx), | |
84 | fESDtrack(t.fESDtrack) | |
85 | { | |
006b5f7f | 86 | //------------------------------------------------------------------ |
87 | //Copy constructor | |
88 | //------------------------------------------------------------------ | |
ef7253ac | 89 | Int_t i; |
ef7253ac | 90 | for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i]; |
6c94f330 | 91 | for (i=0; i<2*kMaxLayer; i++) fIndex[i]=t.fIndex[i]; |
006b5f7f | 92 | } |
a9a2d814 | 93 | |
006b5f7f | 94 | //_____________________________________________________________________________ |
95 | Int_t AliITStrackV2::Compare(const TObject *o) const { | |
96 | //----------------------------------------------------------------- | |
97 | // This function compares tracks according to the their curvature | |
98 | //----------------------------------------------------------------- | |
7f6ddf58 | 99 | AliITStrackV2 *t=(AliITStrackV2*)o; |
6c23ffed | 100 | //Double_t co=OneOverPt(); |
101 | //Double_t c =OneOverPt(); | |
15dd636f | 102 | Double_t co=t->GetSigmaY2()*t->GetSigmaZ2(); |
103 | Double_t c =GetSigmaY2()*GetSigmaZ2(); | |
006b5f7f | 104 | if (c>co) return 1; |
105 | else if (c<co) return -1; | |
106 | return 0; | |
107 | } | |
108 | ||
006b5f7f | 109 | //____________________________________________________________________________ |
6c94f330 | 110 | Bool_t |
111 | AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0) | |
112 | { | |
006b5f7f | 113 | //------------------------------------------------------------------ |
114 | //This function propagates a track to the minimal distance from the origin | |
6c94f330 | 115 | //------------------------------------------------------------------ |
116 | Double_t bz=GetBz(); | |
117 | if (PropagateToDCA(v,bz,kVeryBig)) | |
118 | if (AliExternalTrackParam::CorrectForMaterial(d,x0,GetMass())) return kTRUE; | |
119 | return kFALSE; | |
006b5f7f | 120 | } |
121 | ||
122 | //____________________________________________________________________________ | |
6c94f330 | 123 | Bool_t AliITStrackV2:: |
006b5f7f | 124 | GetGlobalXYZat(Double_t xk, Double_t &x, Double_t &y, Double_t &z) const { |
125 | //------------------------------------------------------------------ | |
126 | //This function returns a track position in the global system | |
127 | //------------------------------------------------------------------ | |
6c94f330 | 128 | Double_t r[3]; |
129 | Bool_t rc=GetXYZAt(xk, AliTracker::GetBz(), r); | |
130 | x=r[0]; y=r[1]; z=r[2]; | |
131 | return rc; | |
006b5f7f | 132 | } |
133 | ||
134 | //_____________________________________________________________________________ | |
6c94f330 | 135 | Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const { |
006b5f7f | 136 | //----------------------------------------------------------------- |
137 | // This function calculates a predicted chi2 increment. | |
138 | //----------------------------------------------------------------- | |
6c94f330 | 139 | Double_t p[2]={c->GetY(), c->GetZ()}; |
140 | Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()}; | |
141 | return AliExternalTrackParam::GetPredictedChi2(p,cov); | |
a9a2d814 | 142 | } |
143 | ||
144 | //____________________________________________________________________________ | |
6c94f330 | 145 | Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) { |
006b5f7f | 146 | //------------------------------------------------------------------ |
147 | //This function propagates a track | |
148 | //------------------------------------------------------------------ | |
afd25725 | 149 | |
6c94f330 | 150 | Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ(); |
006b5f7f | 151 | |
6c94f330 | 152 | Double_t bz=GetBz(); |
153 | if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE; | |
afd25725 | 154 | if (!AliExternalTrackParam::CorrectForMaterial(d,x0,GetMass())) return kFALSE; |
006b5f7f | 155 | |
dd44614b | 156 | Double_t x=GetX(), y=GetY(), z=GetZ(); |
6c94f330 | 157 | if (IsStartedTimeIntegral() && x>oldX) { |
158 | Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ); | |
f29dbb4b | 159 | AddTimeStep(TMath::Sqrt(l2)); |
160 | } | |
f29dbb4b | 161 | |
6c94f330 | 162 | return kTRUE; |
006b5f7f | 163 | } |
164 | ||
afd25725 | 165 | //____________________________________________________________________________ |
166 | Bool_t AliITStrackV2::PropagateToTGeo(Double_t xToGo, Int_t nstep) { | |
167 | //------------------------------------------------------------------- | |
168 | // Propagates the track to a reference plane x=xToGo in n steps. | |
169 | // These n steps are only used to take into account the curvature. | |
170 | // The material is calculated with TGeo. (L.Gaudichet) | |
171 | //------------------------------------------------------------------- | |
172 | ||
173 | Double_t startx = GetX(), starty = GetY(), startz = GetZ(); | |
174 | Double_t sign = (startx<xToGo) ? -1.:1.; | |
175 | Double_t step = (xToGo-startx)/TMath::Abs(nstep); | |
176 | ||
177 | Double_t start[3], end[3], mparam[7], bz = GetBz(); | |
178 | Double_t x = startx; | |
179 | ||
180 | for (Int_t i=0; i<nstep; i++) { | |
181 | ||
182 | GetXYZ(start); //starting global position | |
183 | x += step; | |
184 | if (!GetXYZAt(x, bz, end)) return kFALSE; | |
185 | if (!AliExternalTrackParam::PropagateTo(x, bz)) return kFALSE; | |
186 | AliTracker::MeanMaterialBudget(start, end, mparam); | |
187 | //printf("mparam: %f %f %f %f %f %f %f\n",mparam[0],mparam[1],mparam[2],mparam[3],mparam[4],mparam[5],mparam[6]); | |
188 | if (mparam[1]<900000) { | |
189 | Double_t lengthTimesMeanDensity = sign*mparam[4]*mparam[0]; | |
190 | Double_t xOverX0 = mparam[1]; | |
191 | //printf("%f %f %f CorrectForMeanMaterial(%f,%f)\n",startx,xToGo,sign,xOverX0,lengthTimesMeanDensity); | |
192 | if (!AliExternalTrackParam::CorrectForMeanMaterial(xOverX0, | |
193 | lengthTimesMeanDensity,GetMass())) return kFALSE; | |
194 | } | |
195 | } | |
196 | ||
197 | if (IsStartedTimeIntegral() && GetX()>startx) { | |
198 | Double_t l2 = ( (GetX()-startx)*(GetX()-startx) + | |
199 | (GetY()-starty)*(GetY()-starty) + | |
200 | (GetZ()-startz)*(GetZ()-startz) ); | |
201 | AddTimeStep(TMath::Sqrt(l2)); | |
202 | } | |
203 | ||
204 | return kTRUE; | |
205 | } | |
206 | ||
006b5f7f | 207 | //____________________________________________________________________________ |
6c94f330 | 208 | Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index) |
209 | { | |
006b5f7f | 210 | //------------------------------------------------------------------ |
211 | //This function updates track parameters | |
212 | //------------------------------------------------------------------ | |
6c94f330 | 213 | Double_t p[2]={c->GetY(), c->GetZ()}; |
214 | Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()}; | |
006b5f7f | 215 | |
6c94f330 | 216 | if (!AliExternalTrackParam::Update(p,cov)) return kFALSE; |
006b5f7f | 217 | |
218 | if (!Invariant()) { | |
6c94f330 | 219 | AliWarning("Wrong invariant !"); |
220 | return kFALSE; | |
006b5f7f | 221 | } |
222 | ||
6c94f330 | 223 | if (chi2<0) return kTRUE; |
67c3dcbe | 224 | |
006b5f7f | 225 | Int_t n=GetNumberOfClusters(); |
226 | fIndex[n]=index; | |
227 | SetNumberOfClusters(n+1); | |
228 | SetChi2(GetChi2()+chi2); | |
229 | ||
6c94f330 | 230 | return kTRUE; |
006b5f7f | 231 | } |
232 | ||
6c94f330 | 233 | Bool_t AliITStrackV2::Invariant() const { |
006b5f7f | 234 | //------------------------------------------------------------------ |
235 | // This function is for debugging purpose only | |
236 | //------------------------------------------------------------------ | |
7f6ddf58 | 237 | Int_t n=GetNumberOfClusters(); |
6c94f330 | 238 | |
239 | Double_t sP2=GetParameter()[2]; | |
240 | if (TMath::Abs(sP2) >= kAlmost1){ | |
8602c008 | 241 | if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2); |
6c94f330 | 242 | return kFALSE; |
a9a2d814 | 243 | } |
6c94f330 | 244 | Double_t sC00=GetCovariance()[0]; |
245 | if (sC00<=0 || sC00>9.) { | |
8602c008 | 246 | if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00); |
6c94f330 | 247 | return kFALSE; |
a9a2d814 | 248 | } |
6c94f330 | 249 | Double_t sC11=GetCovariance()[2]; |
250 | if (sC11<=0 || sC11>9.) { | |
8602c008 | 251 | if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11); |
6c94f330 | 252 | return kFALSE; |
a9a2d814 | 253 | } |
6c94f330 | 254 | Double_t sC22=GetCovariance()[5]; |
255 | if (sC22<=0 || sC22>1.) { | |
8602c008 | 256 | if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22); |
6c94f330 | 257 | return kFALSE; |
a9a2d814 | 258 | } |
6c94f330 | 259 | Double_t sC33=GetCovariance()[9]; |
260 | if (sC33<=0 || sC33>1.) { | |
8602c008 | 261 | if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33); |
6c94f330 | 262 | return kFALSE; |
a9a2d814 | 263 | } |
6c94f330 | 264 | Double_t sC44=GetCovariance()[14]; |
265 | if (sC44<=0 /*|| sC44>6e-5*/) { | |
8602c008 | 266 | if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44); |
6c94f330 | 267 | return kFALSE; |
14825d5a | 268 | } |
6c94f330 | 269 | |
270 | return kTRUE; | |
006b5f7f | 271 | } |
272 | ||
273 | //____________________________________________________________________________ | |
6c94f330 | 274 | Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) { |
006b5f7f | 275 | //------------------------------------------------------------------ |
276 | //This function propagates a track | |
277 | //------------------------------------------------------------------ | |
6c94f330 | 278 | Double_t bz=GetBz(); |
279 | if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE; | |
006b5f7f | 280 | |
006b5f7f | 281 | if (!Invariant()) { |
6c94f330 | 282 | AliWarning("Wrong invariant !"); |
283 | return kFALSE; | |
791f9a2a | 284 | } |
285 | ||
6c94f330 | 286 | return kTRUE; |
a9a2d814 | 287 | } |
006b5f7f | 288 | |
afd25725 | 289 | Bool_t AliITStrackV2::MeanBudgetToPrimVertex(Double_t xyz[3], Double_t step, Double_t &d) const { |
290 | ||
291 | //------------------------------------------------------------------- | |
292 | // Get the mean material budget between the actual point and the | |
293 | // primary vertex. (L.Gaudichet) | |
294 | //------------------------------------------------------------------- | |
295 | ||
296 | Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha()); | |
297 | Double_t vertexX = xyz[0]*cs + xyz[1]*sn; | |
298 | ||
299 | Int_t nstep = Int_t((GetX()-vertexX)/step); | |
300 | if (nstep<1) nstep = 1; | |
301 | step = (GetX()-vertexX)/nstep; | |
302 | ||
c7719399 | 303 | // Double_t mparam[7], densMean=0, radLength=0, length=0; |
304 | Double_t mparam[7]; | |
afd25725 | 305 | Double_t p1[3], p2[3], x = GetX(), bz = GetBz(); |
306 | GetXYZ(p1); | |
307 | ||
308 | d=0.; | |
309 | ||
310 | for (Int_t i=0; i<nstep; i++) { | |
311 | x += step; | |
312 | if (!GetXYZAt(x, bz, p2)) return kFALSE; | |
313 | AliTracker::MeanMaterialBudget(p1, p2, mparam); | |
314 | if (mparam[1]>900000) return kFALSE; | |
315 | d += mparam[1]; | |
316 | ||
317 | p1[0] = p2[0]; | |
318 | p1[1] = p2[1]; | |
319 | p1[2] = p2[2]; | |
320 | } | |
321 | ||
322 | return kTRUE; | |
323 | } | |
324 | ||
6c94f330 | 325 | Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) { |
babd135a | 326 | //------------------------------------------------------------------ |
6c94f330 | 327 | //This function improves angular track parameters |
babd135a | 328 | //------------------------------------------------------------------ |
6c94f330 | 329 | Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha()); |
330 | //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex | |
331 | Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the | |
332 | Double_t zv = xyz[2]; // local frame | |
babd135a | 333 | |
6c94f330 | 334 | Double_t dy = Par(0) - yv, dz = Par(1) - zv; |
335 | Double_t r2=GetX()*GetX() + dy*dy; | |
6c23ffed | 336 | Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt()); |
a9a2d814 | 337 | Double_t beta2=p2/(p2 + GetMass()*GetMass()); |
338 | x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp())); | |
8676d691 | 339 | Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0; |
340 | //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33; | |
6c94f330 | 341 | |
342 | Double_t cnv=GetBz()*kB2C; | |
a9a2d814 | 343 | { |
6c94f330 | 344 | Double_t dummy = 4/r2 - GetC()*GetC(); |
345 | if (dummy < 0) return kFALSE; | |
346 | Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy)); | |
347 | Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl()); | |
348 | sigma2p += Cov(0)/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2); | |
349 | sigma2p += ers[1]*ers[1]/r2; | |
350 | sigma2p += 0.25*Cov(14)*cnv*cnv*GetX()*GetX(); | |
00709873 | 351 | Double_t eps2p=sigma2p/(Cov(5) + sigma2p); |
6c94f330 | 352 | Par(0) += Cov(3)/(Cov(5) + sigma2p)*(parp - GetSnp()); |
353 | Par(2) = eps2p*GetSnp() + (1 - eps2p)*parp; | |
354 | Cov(5) *= eps2p; | |
355 | Cov(3) *= eps2p; | |
a9a2d814 | 356 | } |
357 | { | |
6c94f330 | 358 | Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2)); |
359 | Double_t sigma2l=theta2; | |
360 | sigma2l += Cov(2)/r2 + Cov(0)*dy*dy*dz*dz/(r2*r2*r2); | |
361 | sigma2l += ers[2]*ers[2]/r2; | |
362 | Double_t eps2l = sigma2l/(Cov(9) + sigma2l); | |
363 | Par(1) += Cov(7 )/(Cov(9) + sigma2l)*(parl - Par(3)); | |
364 | Par(4) += Cov(13)/(Cov(9) + sigma2l)*(parl - Par(3)); | |
365 | Par(3) = eps2l*Par(3) + (1-eps2l)*parl; | |
366 | Cov(9) *= eps2l; | |
00709873 | 367 | Cov(13)*= eps2l; |
6c94f330 | 368 | Cov(7) *= eps2l; |
a9a2d814 | 369 | } |
6c94f330 | 370 | if (!Invariant()) return kFALSE; |
14825d5a | 371 | |
6c94f330 | 372 | return kTRUE; |
14825d5a | 373 | } |
23efe5f1 | 374 | |
375 | void AliITStrackV2::CookdEdx(Double_t low, Double_t up) { | |
376 | //----------------------------------------------------------------- | |
a9a2d814 | 377 | // This function calculates dE/dX within the "low" and "up" cuts. |
378 | // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch | |
23efe5f1 | 379 | //----------------------------------------------------------------- |
23efe5f1 | 380 | // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1 |
c0dd5278 | 381 | |
382 | Int_t i; | |
383 | Int_t nc=0; | |
384 | for (i=0; i<GetNumberOfClusters(); i++) { | |
385 | Int_t idx=GetClusterIndex(i); | |
386 | idx=(idx&0xf0000000)>>28; | |
387 | if (idx>1) nc++; // Take only SSD and SDD | |
388 | } | |
23efe5f1 | 389 | |
a9a2d814 | 390 | Int_t swap;//stupid sorting |
23efe5f1 | 391 | do { |
392 | swap=0; | |
393 | for (i=0; i<nc-1; i++) { | |
394 | if (fdEdxSample[i]<=fdEdxSample[i+1]) continue; | |
395 | Float_t tmp=fdEdxSample[i]; | |
396 | fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp; | |
397 | swap++; | |
398 | } | |
399 | } while (swap); | |
400 | ||
a9a2d814 | 401 | Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX |
402 | // values from four ones choose | |
403 | // nu=2 | |
23efe5f1 | 404 | Float_t dedx=0; |
a9a2d814 | 405 | for (i=nl; i<nu; i++) dedx += fdEdxSample[i]; |
c0dd5278 | 406 | if (nu-nl>0) dedx /= (nu-nl); |
23efe5f1 | 407 | |
23efe5f1 | 408 | SetdEdx(dedx); |
409 | } | |
c7bafca9 | 410 | |
6c94f330 | 411 | Double_t AliITStrackV2::GetBz() const { |
412 | // | |
413 | // returns Bz component of the magnetic field (kG) | |
414 | // | |
415 | if (AliTracker::UniformField()) return AliTracker::GetBz(); | |
416 | Double_t r[3]; GetXYZ(r); | |
417 | return AliTracker::GetBz(r); | |
5773defd | 418 | } |
6c94f330 | 419 | |
8602c008 | 420 | //____________________________________________________________________________ |
421 | Bool_t AliITStrackV2:: | |
422 | GetPhiZat(Double_t rk, Double_t &phik, Double_t &zk) const { | |
423 | //------------------------------------------------------------------ | |
424 | // This function returns the global cylindrical (phik,zk) of the track | |
425 | // position estimated at the radius rk. | |
426 | // The track curvature is neglected. | |
427 | //------------------------------------------------------------------ | |
428 | Double_t d=GetD(0.,0.); | |
429 | if (TMath::Abs(d) > rk) return kFALSE; | |
430 | ||
431 | Double_t r=TMath::Sqrt(GetX()*GetX() + GetY()*GetY()); | |
432 | Double_t phi=GetAlpha()+TMath::ASin(GetSnp()); | |
433 | ||
434 | phik=phi+TMath::ASin(d/rk)-TMath::ASin(d/r); | |
435 | zk=GetZ()+GetTgl()*(TMath::Sqrt(rk*rk-d*d) - TMath::Sqrt(r*r-d*d)); | |
436 | ||
437 | return kTRUE; | |
438 | } | |
439 |