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73042f01 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
0938c7d3 16/*
17$Log$
9c9d2487 18Revision 1.19 2003/03/03 16:56:53 hristov
19Corrections to obey coding conventions
20
7c27857f 21Revision 1.18 2003/02/19 08:57:04 hristov
22Control^M removed
23
0d2d27b0 24Revision 1.17 2003/02/19 08:49:46 hristov
25Track time measurement (S.Radomski)
26
e3f7105e 27Revision 1.16 2003/02/06 11:11:36 kowal2
28Added a few get methods by Jiri Chudoba
29
77e58468 30Revision 1.15 2002/11/25 09:33:30 hristov
31Tracking of secondaries (M.Ivanov)
32
1627d1c4 33Revision 1.14 2002/10/23 13:45:00 hristov
34Fatal if no magnetic field set for the reconstruction (Y.Belikov)
35
e1a65e92 36Revision 1.13 2002/10/23 07:17:34 alibrary
37Introducing Riostream.h
38
19364939 39Revision 1.12 2002/10/14 14:57:43 hristov
40Merging the VirtualMC branch to the main development branch (HEAD)
41
b9d0a01d 42Revision 1.9.6.1 2002/10/11 08:34:48 hristov
43Updating VirtualMC to v3-09-02
44
45Revision 1.11 2002/07/19 07:34:42 kowal2
46Logs added
47
0938c7d3 48*/
49
50
73042f01 51//-----------------------------------------------------------------
52// Implementation of the TPC track class
7c27857f 53// This class is used by the AliTPCtracker class
54// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
73042f01 55//-----------------------------------------------------------------
56
19364939 57#include <Riostream.h>
b19a0509 58
73042f01 59#include "AliTPCtrack.h"
7c27857f 60#include "AliCluster.h"
9c9d2487 61#include "AliBarrelTrack.h"
73042f01 62
63ClassImp(AliTPCtrack)
b9de75e1 64
e3f7105e 65//_________________________________________________________________________
66AliTPCtrack::AliTPCtrack(): AliKalmanTrack()
67{
68 fX = fP0 = fP1 = fP2 = fP3 = fP3 = fP4 = 0.0;
69 fAlpha = fdEdx = 0.0;
9c9d2487 70 fNWrong = fNRotation = fNumber = 0; // [SR, 01.04.2003]
e3f7105e 71}
72
73042f01 73//_________________________________________________________________________
74AliTPCtrack::AliTPCtrack(UInt_t index, const Double_t xx[5],
b19a0509 75const Double_t cc[15], Double_t xref, Double_t alpha) : AliKalmanTrack() {
73042f01 76 //-----------------------------------------------------------------
77 // This is the main track constructor.
78 //-----------------------------------------------------------------
73042f01 79 fX=xref;
be9c5115 80 fAlpha=alpha;
81 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
82 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
83 fdEdx=0.;
73042f01 84
b19a0509 85 fP0=xx[0]; fP1=xx[1]; fP2=xx[2]; fP3=xx[3]; fP4=xx[4];
73042f01 86
b19a0509 87 fC00=cc[0];
88 fC10=cc[1]; fC11=cc[2];
89 fC20=cc[3]; fC21=cc[4]; fC22=cc[5];
90 fC30=cc[6]; fC31=cc[7]; fC32=cc[8]; fC33=cc[9];
91 fC40=cc[10]; fC41=cc[11]; fC42=cc[12]; fC43=cc[13]; fC44=cc[14];
73042f01 92
be9c5115 93 fIndex[0]=index;
94 SetNumberOfClusters(1);
b9de75e1 95
96}
97
98//_____________________________________________________________________________
e1a65e92 99AliTPCtrack::AliTPCtrack(const AliKalmanTrack& t,Double_t alpha) :
100AliKalmanTrack(t) {
b9de75e1 101 //-----------------------------------------------------------------
102 // Conversion AliKalmanTrack -> AliTPCtrack.
103 //-----------------------------------------------------------------
b9de75e1 104 SetChi2(0.);
105 SetNumberOfClusters(0);
b9de75e1 106
107 fdEdx = 0.;
108 fAlpha = alpha;
109 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
110 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
111
112 //Conversion of the track parameters
113 Double_t x,p[5]; t.GetExternalParameters(x,p);
114 fX=x; x=GetConvConst();
115 fP0=p[0];
116 fP1=p[1];
117 fP3=p[3];
118 fP4=p[4]/x;
119 fP2=fP4*fX - p[2];
120
121 //Conversion of the covariance matrix
122 Double_t c[15]; t.GetExternalCovariance(c);
123 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
124
125 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
126 Double_t c32=fX*c[13] - c[8];
127 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
128
129 fC00=c[0 ];
130 fC10=c[1 ]; fC11=c[2 ];
131 fC20=c20; fC21=c21; fC22=c22;
132 fC30=c[6 ]; fC31=c[7 ]; fC32=c32; fC33=c[9 ];
133 fC40=c[10]; fC41=c[11]; fC42=c42; fC43=c[13]; fC44=c[14];
134
73042f01 135}
136
137//_____________________________________________________________________________
b19a0509 138AliTPCtrack::AliTPCtrack(const AliTPCtrack& t) : AliKalmanTrack(t) {
73042f01 139 //-----------------------------------------------------------------
140 // This is a track copy constructor.
141 //-----------------------------------------------------------------
be9c5115 142 fX=t.fX;
143 fAlpha=t.fAlpha;
73042f01 144 fdEdx=t.fdEdx;
145
be9c5115 146 fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4;
147
148 fC00=t.fC00;
149 fC10=t.fC10; fC11=t.fC11;
150 fC20=t.fC20; fC21=t.fC21; fC22=t.fC22;
151 fC30=t.fC30; fC31=t.fC31; fC32=t.fC32; fC33=t.fC33;
152 fC40=t.fC40; fC41=t.fC41; fC42=t.fC42; fC43=t.fC43; fC44=t.fC44;
153
154 Int_t n=GetNumberOfClusters();
155 for (Int_t i=0; i<n; i++) fIndex[i]=t.fIndex[i];
156}
9c9d2487 157//_____________________________________________________________________________
158
159void AliTPCtrack::GetBarrelTrack(AliBarrelTrack *track) {
160 //
161 // Create a Barrel Track out of this track
162 // Current track is propagated to the reference plane
163 // by the tracker
164 //
165 // [SR, 01.04.2003]
166
167 if (!track) return;
168 Double_t xr, vec[5], cov[15];
169
170 track->SetLabel(GetLabel());
171 track->SetX(fX, fAlpha);
172 track->SetNClusters(GetNumberOfClusters(), GetChi2());
173 track->SetTime(fIntegratedTime, fIntegratedLength);
174
175 track->SetMass(fMass);
176 track->SetdEdX(fdEdx);
177
178 track->SetNWrongClusters(fNWrong);
179 track->SetNRotate(fNRotation);
be9c5115 180
9c9d2487 181 GetExternalParameters(xr, vec);
182 track->SetStateVector(vec);
183
184 GetExternalCovariance(cov);
185 track->SetCovarianceMatrix(cov);
186
187}
be9c5115 188//_____________________________________________________________________________
189Int_t AliTPCtrack::Compare(const TObject *o) const {
190 //-----------------------------------------------------------------
191 // This function compares tracks according to the their curvature
192 //-----------------------------------------------------------------
193 AliTPCtrack *t=(AliTPCtrack*)o;
024a7fe9 194 //Double_t co=TMath::Abs(t->Get1Pt());
195 //Double_t c =TMath::Abs(Get1Pt());
196 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
197 Double_t c =GetSigmaY2()*GetSigmaZ2();
be9c5115 198 if (c>co) return 1;
199 else if (c<co) return -1;
200 return 0;
201}
202
203//_____________________________________________________________________________
204void AliTPCtrack::GetExternalCovariance(Double_t cc[15]) const {
205 //-------------------------------------------------------------------------
206 // This function returns an external representation of the covriance matrix.
207 // (See comments in AliTPCtrack.h about external track representation)
208 //-------------------------------------------------------------------------
9b280d80 209 Double_t a=GetConvConst();
be9c5115 210
b9de75e1 211 Double_t c22=fX*fX*fC44-2*fX*fC42+fC22;
212 Double_t c32=fX*fC43-fC32;
213 Double_t c20=fX*fC40-fC20, c21=fX*fC41-fC21, c42=fX*fC44-fC42;
be9c5115 214
215 cc[0 ]=fC00;
216 cc[1 ]=fC10; cc[2 ]=fC11;
217 cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22;
b9de75e1 218 cc[6 ]=fC30; cc[7 ]=fC31; cc[8 ]=c32; cc[9 ]=fC33;
219 cc[10]=fC40*a; cc[11]=fC41*a; cc[12]=c42*a; cc[13]=fC43*a; cc[14]=fC44*a*a;
be9c5115 220
221}
222
223//_____________________________________________________________________________
224Double_t AliTPCtrack::GetPredictedChi2(const AliCluster *c) const
225{
226 //-----------------------------------------------------------------
227 // This function calculates a predicted chi2 increment.
228 //-----------------------------------------------------------------
229 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
230 r00+=fC00; r01+=fC10; r11+=fC11;
231
232 Double_t det=r00*r11 - r01*r01;
233 if (TMath::Abs(det) < 1.e-10) {
234 Int_t n=GetNumberOfClusters();
235 if (n>4) cerr<<n<<" AliKalmanTrack warning: Singular matrix !\n";
236 return 1e10;
237 }
238 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
239
240 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
241
242 return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
73042f01 243}
244
245//_____________________________________________________________________________
7f6ddf58 246Int_t AliTPCtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho) {
73042f01 247 //-----------------------------------------------------------------
248 // This function propagates a track to a reference plane x=xk.
249 //-----------------------------------------------------------------
1627d1c4 250 if (TMath::Abs(fP4*xk - fP2) >= 0.9) {
251 // Int_t n=GetNumberOfClusters();
252 //if (n>4) cerr<<n<<" AliTPCtrack warning: Propagation failed !\n";
73042f01 253 return 0;
254 }
e3f7105e 255
256 // old position for time [SR, GSI 17.02.2003]
257 Double_t oldX = fX;
258 Double_t oldY = fP0;
259 Double_t oldZ = fP1;
260 //
73042f01 261
b19a0509 262 Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fP0, z1=fP1;
b9de75e1 263 Double_t c1=fP4*x1 - fP2, r1=sqrt(1.- c1*c1);
264 Double_t c2=fP4*x2 - fP2, r2=sqrt(1.- c2*c2);
73042f01 265
b19a0509 266 fP0 += dx*(c1+c2)/(r1+r2);
b9de75e1 267 fP1 += dx*(c1+c2)/(c1*r2 + c2*r1)*fP3;
73042f01 268
269 //f = F - 1
270 Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
b19a0509 271 Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
b9de75e1 272 Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
73042f01 273 Double_t cr=c1*r2+c2*r1;
b9de75e1 274 Double_t f12=-dx*fP3*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
275 Double_t f13= dx*cc/cr;
276 Double_t f14=dx*fP3*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);
73042f01 277
278 //b = C*ft
b9de75e1 279 Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30;
280 Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31;
281 Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32;
282 Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33;
283 Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43;
73042f01 284
285 //a = f*b = f*C*ft
b9de75e1 286 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31;
73042f01 287
288 //F*C*Ft = C + (a + b + bt)
b19a0509 289 fC00 += a00 + 2*b00;
290 fC10 += a01 + b01 + b10;
291 fC20 += b20;
292 fC30 += b30;
293 fC40 += b40;
294 fC11 += a11 + 2*b11;
295 fC21 += b21;
296 fC31 += b31;
297 fC41 += b41;
73042f01 298
299 fX=x2;
300
301 //Multiple scattering******************
b19a0509 302 Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fP0)*(y1-fP0)+(z1-fP1)*(z1-fP1));
be9c5115 303 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
7f6ddf58 304 Double_t beta2=p2/(p2 + GetMass()*GetMass());
024a7fe9 305 //Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
306 Double_t theta2=1.0259e-6*10*10/20/(beta2*p2)*d*rho;
73042f01 307
b9de75e1 308 Double_t ey=fP4*fX - fP2, ez=fP3;
309 Double_t xz=fP4*ez, zz1=ez*ez+1, xy=fP2+ey;
73042f01 310
b19a0509 311 fC22 += (2*ey*ez*ez*fP2+1-ey*ey+ez*ez+fP2*fP2*ez*ez)*theta2;
b9de75e1 312 fC32 += ez*zz1*xy*theta2;
313 fC33 += zz1*zz1*theta2;
314 fC42 += xz*ez*xy*theta2;
315 fC43 += xz*zz1*theta2;
316 fC44 += xz*xz*theta2;
73042f01 317
318 //Energy losses************************
319 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d*rho;
320 if (x1 < x2) dE=-dE;
b9de75e1 321 cc=fP4;
7f6ddf58 322 fP4*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
b9de75e1 323 fP2+=fX*(fP4-cc);
73042f01 324
e3f7105e 325 // Integrated Time [SR, GSI, 17.02.2003]
326 if (IsStartedTimeIntegral()) {
327 Double_t l2 = (fX-oldX)*(fX-oldX)+(fP0-oldY)*(fP0-oldY)+(fP1-oldZ)*(fP1-oldZ);
328 AddTimeStep(TMath::Sqrt(l2));
329 }
330 //
331
73042f01 332 return 1;
333}
334
335//_____________________________________________________________________________
7f6ddf58 336Int_t AliTPCtrack::PropagateToVertex(Double_t x0,Double_t rho)
73042f01 337{
338 //-----------------------------------------------------------------
339 // This function propagates tracks to the "vertex".
340 //-----------------------------------------------------------------
b9de75e1 341 Double_t c=fP4*fX - fP2;
342 Double_t tgf=-fP2/(fP4*fP0 + sqrt(1-c*c));
73042f01 343 Double_t snf=tgf/sqrt(1.+ tgf*tgf);
b9de75e1 344 Double_t xv=(fP2+snf)/fP4;
7f6ddf58 345 return PropagateTo(xv,x0,rho);
73042f01 346}
347
348//_____________________________________________________________________________
be9c5115 349Int_t AliTPCtrack::Update(const AliCluster *c, Double_t chisq, UInt_t index) {
73042f01 350 //-----------------------------------------------------------------
351 // This function associates a cluster with this track.
352 //-----------------------------------------------------------------
9c9d2487 353
354 // update the number of wrong SR[20.03.2003]
355 Int_t absLabel = TMath::Abs(GetLabel());
356 if ( (c->GetLabel(0) != absLabel) &&
357 (c->GetLabel(0) != absLabel) &&
358 (c->GetLabel(0) != absLabel)) fNWrong++;
359 //
360
73042f01 361 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
b19a0509 362 r00+=fC00; r01+=fC10; r11+=fC11;
73042f01 363 Double_t det=r00*r11 - r01*r01;
364 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
365
b19a0509 366 Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11;
367 Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11;
368 Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11;
369 Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11;
370 Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11;
73042f01 371
b19a0509 372 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
b9de75e1 373 Double_t cur=fP4 + k40*dy + k41*dz, eta=fP2 + k20*dy + k21*dz;
1627d1c4 374 if (TMath::Abs(cur*fX-eta) >= 0.9) {
375 // Int_t n=GetNumberOfClusters();
376 //if (n>4) cerr<<n<<" AliTPCtrack warning: Filtering failed !\n";
be9c5115 377 return 0;
73042f01 378 }
379
b19a0509 380 fP0 += k00*dy + k01*dz;
381 fP1 += k10*dy + k11*dz;
382 fP2 = eta;
b9de75e1 383 fP3 += k30*dy + k31*dz;
384 fP4 = cur;
73042f01 385
b19a0509 386 Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40;
387 Double_t c12=fC21, c13=fC31, c14=fC41;
73042f01 388
b19a0509 389 fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11;
390 fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13;
391 fC40-=k00*c04+k01*c14;
73042f01 392
b19a0509 393 fC11-=k10*c01+k11*fC11;
394 fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13;
395 fC41-=k10*c04+k11*c14;
73042f01 396
b19a0509 397 fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13;
398 fC42-=k20*c04+k21*c14;
73042f01 399
b19a0509 400 fC33-=k30*c03+k31*c13;
b9de75e1 401 fC43-=k40*c03+k41*c13;
73042f01 402
b19a0509 403 fC44-=k40*c04+k41*c14;
73042f01 404
be9c5115 405 Int_t n=GetNumberOfClusters();
406 fIndex[n]=index;
407 SetNumberOfClusters(n+1);
408 SetChi2(GetChi2()+chisq);
409
410 return 1;
73042f01 411}
412
413//_____________________________________________________________________________
414Int_t AliTPCtrack::Rotate(Double_t alpha)
415{
416 //-----------------------------------------------------------------
417 // This function rotates this track.
418 //-----------------------------------------------------------------
9c9d2487 419
420 if (alpha != 0) fNRotation++; // [SR, 01.04.2003]
421
73042f01 422 fAlpha += alpha;
be9c5115 423 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
424 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
73042f01 425
b19a0509 426 Double_t x1=fX, y1=fP0;
73042f01 427 Double_t ca=cos(alpha), sa=sin(alpha);
b9de75e1 428 Double_t r1=fP4*fX - fP2;
73042f01 429
430 fX = x1*ca + y1*sa;
b19a0509 431 fP0=-x1*sa + y1*ca;
b9de75e1 432 fP2=fP2*ca + (fP4*y1 + sqrt(1.- r1*r1))*sa;
73042f01 433
b9de75e1 434 Double_t r2=fP4*fX - fP2;
73042f01 435 if (TMath::Abs(r2) >= 0.99999) {
be9c5115 436 Int_t n=GetNumberOfClusters();
437 if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !\n";
73042f01 438 return 0;
439 }
440
b9de75e1 441 Double_t y0=fP0 + sqrt(1.- r2*r2)/fP4;
442 if ((fP0-y0)*fP4 >= 0.) {
be9c5115 443 Int_t n=GetNumberOfClusters();
444 if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !!!\n";
73042f01 445 return 0;
446 }
447
448 //f = F - 1
b9de75e1 449 Double_t f00=ca-1, f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa,
450 f20=fP4*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1;
73042f01 451
452 //b = C*ft
b9de75e1 453 Double_t b00=fC00*f00, b02=fC00*f20+fC40*f24+fC20*f22;
454 Double_t b10=fC10*f00, b12=fC10*f20+fC41*f24+fC21*f22;
455 Double_t b20=fC20*f00, b22=fC20*f20+fC42*f24+fC22*f22;
456 Double_t b30=fC30*f00, b32=fC30*f20+fC43*f24+fC32*f22;
457 Double_t b40=fC40*f00, b42=fC40*f20+fC44*f24+fC42*f22;
73042f01 458
459 //a = f*b = f*C*ft
b9de75e1 460 Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22;
73042f01 461
462 // *** Double_t dy2=fCyy;
463
464 //F*C*Ft = C + (a + b + bt)
b19a0509 465 fC00 += a00 + 2*b00;
466 fC10 += b10;
467 fC20 += a02+b20+b02;
468 fC30 += b30;
469 fC40 += b40;
470 fC21 += b12;
471 fC32 += b32;
472 fC22 += a22 + 2*b22;
473 fC42 += b42;
73042f01 474
475 // *** fCyy+=dy2*sa*sa*r1*r1/(1.- r1*r1);
476 // *** fCzz+=d2y*sa*sa*fT*fT/(1.- r1*r1);
477
478 return 1;
479}
480
b9de75e1 481void AliTPCtrack::ResetCovariance() {
482 //------------------------------------------------------------------
483 //This function makes a track forget its history :)
484 //------------------------------------------------------------------
485
486 fC00*=10.;
487 fC10=0.; fC11*=10.;
488 fC20=0.; fC21=0.; fC22*=10.;
489 fC30=0.; fC31=0.; fC32=0.; fC33*=10.;
490 fC40=0.; fC41=0.; fC42=0.; fC43=0.; fC44*=10.;
491
73042f01 492}
77e58468 493
494////////////////////////////////////////////////////////////////////////
495Double_t AliTPCtrack::Phi() const {
7c27857f 496//
497//
498//
77e58468 499 Double_t phi = TMath::ASin(GetSnp()) + fAlpha;
500 if (phi<0) phi+=2*TMath::Pi();
501 if (phi>=2*TMath::Pi()) phi-=2*TMath::Pi();
502 return phi;
503}
504////////////////////////////////////////////////////////////////////////
505