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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
803d1ab0 16/* $Id$ */
0938c7d3 17
73042f01 18//-----------------------------------------------------------------
19// Implementation of the TPC track class
7c27857f 20// This class is used by the AliTPCtracker class
21// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
73042f01 22//-----------------------------------------------------------------
23
19364939 24#include <Riostream.h>
b19a0509 25
73042f01 26#include "AliTPCtrack.h"
7c27857f 27#include "AliCluster.h"
83d73500 28#include "AliESDtrack.h"
73042f01 29
30ClassImp(AliTPCtrack)
b9de75e1 31
e3f7105e 32//_________________________________________________________________________
33AliTPCtrack::AliTPCtrack(): AliKalmanTrack()
34{
2fc0c115 35 //-------------------------------------------------
36 // default constructor
37 //-------------------------------------------------
e3f7105e 38 fX = fP0 = fP1 = fP2 = fP3 = fP3 = fP4 = 0.0;
39 fAlpha = fdEdx = 0.0;
24de2d6d 40 fNumber = 0; // [SR, 01.04.2003]
51ad6848 41 for (Int_t i=0; i<3;i++) fKinkIndexes[i]=0;
e3f7105e 42}
43
73042f01 44//_________________________________________________________________________
51ad6848 45
46
47
73042f01 48AliTPCtrack::AliTPCtrack(UInt_t index, const Double_t xx[5],
b19a0509 49const Double_t cc[15], Double_t xref, Double_t alpha) : AliKalmanTrack() {
73042f01 50 //-----------------------------------------------------------------
51 // This is the main track constructor.
52 //-----------------------------------------------------------------
73042f01 53 fX=xref;
be9c5115 54 fAlpha=alpha;
55 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
56 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
57 fdEdx=0.;
73042f01 58
b19a0509 59 fP0=xx[0]; fP1=xx[1]; fP2=xx[2]; fP3=xx[3]; fP4=xx[4];
73042f01 60
b19a0509 61 fC00=cc[0];
62 fC10=cc[1]; fC11=cc[2];
63 fC20=cc[3]; fC21=cc[4]; fC22=cc[5];
64 fC30=cc[6]; fC31=cc[7]; fC32=cc[8]; fC33=cc[9];
65 fC40=cc[10]; fC41=cc[11]; fC42=cc[12]; fC43=cc[13]; fC44=cc[14];
73042f01 66
be9c5115 67 fIndex[0]=index;
68 SetNumberOfClusters(1);
51584047 69 //
70 //MI
71 fSdEdx = 0;
72 fNFoundable = 0;
73 fBConstrain = 0;
74 fLastPoint = 0;
75 fFirstPoint = 0;
76 fRemoval = 0;
77 fTrackType = 0;
78 fLab2 = 0;
51ad6848 79 for (Int_t i=0; i<3;i++) fKinkIndexes[i]=0;
b9de75e1 80}
81
83d73500 82//_____________________________________________________________________________
83AliTPCtrack::AliTPCtrack(const AliESDtrack& t) : AliKalmanTrack() {
84 //-----------------------------------------------------------------
85 // Conversion AliESDtrack -> AliTPCtrack.
86 //-----------------------------------------------------------------
87 SetNumberOfClusters(t.GetTPCclusters(fIndex));
88 SetLabel(t.GetLabel());
89 SetMass(t.GetMass());
51ad6848 90 for (Int_t i=0; i<3;i++) fKinkIndexes[i]=t.GetKinkIndex(i);
83d73500 91
92 fdEdx = t.GetTPCsignal();
93 fAlpha = t.GetAlpha();
94 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
95 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
96
97 //Conversion of the track parameters
98 Double_t x,p[5]; t.GetExternalParameters(x,p);
51ad6848 99 Double_t c[15]; t.GetExternalCovariance(c);
100
83d73500 101 fX=x; x=GetConvConst();
102 fP0=p[0];
103 fP1=p[1];
104 fP3=p[3];
105 fP4=p[4]/x;
106 fP2=fP4*fX - p[2];
107
108 //Conversion of the covariance matrix
83d73500 109 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
110
111 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
112 Double_t c32=fX*c[13] - c[8];
113 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
114
115 fC00=c[0 ];
116 fC10=c[1 ]; fC11=c[2 ];
117 fC20=c20; fC21=c21; fC22=c22;
118 fC30=c[6 ]; fC31=c[7 ]; fC32=c32; fC33=c[9 ];
119 fC40=c[10]; fC41=c[11]; fC42=c42; fC43=c[13]; fC44=c[14];
120
0798b21e 121 if ((t.GetStatus()&AliESDtrack::kTIME) == 0) return;
83d73500 122 StartTimeIntegral();
123 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
124 SetIntegratedLength(t.GetIntegratedLength());
51584047 125 //
126 //MI
127 fSdEdx = 0;
128 fNFoundable = 0;
129 fBConstrain = 0;
130 fLastPoint = 0;
131 fFirstPoint = 0;
132 fRemoval = 0;
133 fTrackType = 0;
134 fLab2 = 0;
babd135a 135 // SetFakeRatio(t.GetTPCFakeRatio());
83d73500 136}
137
73042f01 138//_____________________________________________________________________________
b19a0509 139AliTPCtrack::AliTPCtrack(const AliTPCtrack& t) : AliKalmanTrack(t) {
73042f01 140 //-----------------------------------------------------------------
141 // This is a track copy constructor.
142 //-----------------------------------------------------------------
be9c5115 143 fX=t.fX;
144 fAlpha=t.fAlpha;
73042f01 145 fdEdx=t.fdEdx;
146
be9c5115 147 fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4;
148
149 fC00=t.fC00;
150 fC10=t.fC10; fC11=t.fC11;
151 fC20=t.fC20; fC21=t.fC21; fC22=t.fC22;
152 fC30=t.fC30; fC31=t.fC31; fC32=t.fC32; fC33=t.fC33;
153 fC40=t.fC40; fC41=t.fC41; fC42=t.fC42; fC43=t.fC43; fC44=t.fC44;
154
176aff27 155 //Int_t n=GetNumberOfClusters();
51584047 156 for (Int_t i=0; i<kMaxRow; i++) fIndex[i]=t.fIndex[i];
157 //
158 //MI
159 fSdEdx = t.fSdEdx;
160 fNFoundable = t.fNFoundable;
161 fBConstrain = t.fBConstrain;
162 fLastPoint = t.fLastPoint;
163 fFirstPoint = t.fFirstPoint;
164 fRemoval = t.fRemoval ;
165 fTrackType = t.fTrackType;
166 fLab2 = t.fLab2;
51ad6848 167 for (Int_t i=0; i<3;i++) fKinkIndexes[i]=t.fKinkIndexes[i];
be9c5115 168}
169
170//_____________________________________________________________________________
171Int_t AliTPCtrack::Compare(const TObject *o) const {
172 //-----------------------------------------------------------------
173 // This function compares tracks according to the their curvature
174 //-----------------------------------------------------------------
175 AliTPCtrack *t=(AliTPCtrack*)o;
024a7fe9 176 //Double_t co=TMath::Abs(t->Get1Pt());
177 //Double_t c =TMath::Abs(Get1Pt());
178 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
179 Double_t c =GetSigmaY2()*GetSigmaZ2();
be9c5115 180 if (c>co) return 1;
181 else if (c<co) return -1;
182 return 0;
183}
184
185//_____________________________________________________________________________
186void AliTPCtrack::GetExternalCovariance(Double_t cc[15]) const {
187 //-------------------------------------------------------------------------
188 // This function returns an external representation of the covriance matrix.
189 // (See comments in AliTPCtrack.h about external track representation)
190 //-------------------------------------------------------------------------
9b280d80 191 Double_t a=GetConvConst();
be9c5115 192
b9de75e1 193 Double_t c22=fX*fX*fC44-2*fX*fC42+fC22;
194 Double_t c32=fX*fC43-fC32;
195 Double_t c20=fX*fC40-fC20, c21=fX*fC41-fC21, c42=fX*fC44-fC42;
be9c5115 196
197 cc[0 ]=fC00;
198 cc[1 ]=fC10; cc[2 ]=fC11;
199 cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22;
b9de75e1 200 cc[6 ]=fC30; cc[7 ]=fC31; cc[8 ]=c32; cc[9 ]=fC33;
201 cc[10]=fC40*a; cc[11]=fC41*a; cc[12]=c42*a; cc[13]=fC43*a; cc[14]=fC44*a*a;
be9c5115 202
203}
204
205//_____________________________________________________________________________
206Double_t AliTPCtrack::GetPredictedChi2(const AliCluster *c) const
207{
208 //-----------------------------------------------------------------
209 // This function calculates a predicted chi2 increment.
210 //-----------------------------------------------------------------
211 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
212 r00+=fC00; r01+=fC10; r11+=fC11;
213
214 Double_t det=r00*r11 - r01*r01;
215 if (TMath::Abs(det) < 1.e-10) {
216 Int_t n=GetNumberOfClusters();
217 if (n>4) cerr<<n<<" AliKalmanTrack warning: Singular matrix !\n";
218 return 1e10;
219 }
220 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
221
222 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
223
224 return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
73042f01 225}
226
c630aafd 227Double_t AliTPCtrack::GetYat(Double_t xk) const {
228//-----------------------------------------------------------------
229// This function calculates the Y-coordinate of a track at the plane x=xk.
230//-----------------------------------------------------------------
231 Double_t c1=fP4*fX - fP2, r1=TMath::Sqrt(1.- c1*c1);
df02fd67 232 Double_t c2=fP4*xk - fP2;
233 if (c2*c2>0.99999) {
234 Int_t n=GetNumberOfClusters();
235 if (n>4) cerr<<n<<"AliTPCtrack::GetYat: can't evaluate the y-coord !\n";
236 return 1e10;
237 }
238 Double_t r2=TMath::Sqrt(1.- c2*c2);
c630aafd 239 return fP0 + (xk-fX)*(c1+c2)/(r1+r2);
240}
241
73042f01 242//_____________________________________________________________________________
176aff27 243Int_t AliTPCtrack::PropagateTo(Double_t xk,Double_t /*x0*/,Double_t rho) {
73042f01 244 //-----------------------------------------------------------------
245 // This function propagates a track to a reference plane x=xk.
246 //-----------------------------------------------------------------
1627d1c4 247 if (TMath::Abs(fP4*xk - fP2) >= 0.9) {
248 // Int_t n=GetNumberOfClusters();
249 //if (n>4) cerr<<n<<" AliTPCtrack warning: Propagation failed !\n";
73042f01 250 return 0;
251 }
e3f7105e 252
253 // old position for time [SR, GSI 17.02.2003]
254 Double_t oldX = fX;
255 Double_t oldY = fP0;
256 Double_t oldZ = fP1;
257 //
73042f01 258
b19a0509 259 Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fP0, z1=fP1;
b9de75e1 260 Double_t c1=fP4*x1 - fP2, r1=sqrt(1.- c1*c1);
261 Double_t c2=fP4*x2 - fP2, r2=sqrt(1.- c2*c2);
73042f01 262
b19a0509 263 fP0 += dx*(c1+c2)/(r1+r2);
b9de75e1 264 fP1 += dx*(c1+c2)/(c1*r2 + c2*r1)*fP3;
73042f01 265
266 //f = F - 1
267 Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
b19a0509 268 Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
b9de75e1 269 Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
73042f01 270 Double_t cr=c1*r2+c2*r1;
b9de75e1 271 Double_t f12=-dx*fP3*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
272 Double_t f13= dx*cc/cr;
273 Double_t f14=dx*fP3*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);
73042f01 274
275 //b = C*ft
b9de75e1 276 Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30;
277 Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31;
278 Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32;
279 Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33;
280 Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43;
73042f01 281
282 //a = f*b = f*C*ft
b9de75e1 283 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31;
73042f01 284
285 //F*C*Ft = C + (a + b + bt)
b19a0509 286 fC00 += a00 + 2*b00;
287 fC10 += a01 + b01 + b10;
288 fC20 += b20;
289 fC30 += b30;
290 fC40 += b40;
291 fC11 += a11 + 2*b11;
292 fC21 += b21;
293 fC31 += b31;
294 fC41 += b41;
73042f01 295
296 fX=x2;
297
298 //Multiple scattering******************
b19a0509 299 Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fP0)*(y1-fP0)+(z1-fP1)*(z1-fP1));
be9c5115 300 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
7f6ddf58 301 Double_t beta2=p2/(p2 + GetMass()*GetMass());
babd135a 302 beta2 = TMath::Min(beta2,0.99999999999);
024a7fe9 303 //Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
304 Double_t theta2=1.0259e-6*10*10/20/(beta2*p2)*d*rho;
73042f01 305
b9de75e1 306 Double_t ey=fP4*fX - fP2, ez=fP3;
307 Double_t xz=fP4*ez, zz1=ez*ez+1, xy=fP2+ey;
982aff31 308
b19a0509 309 fC22 += (2*ey*ez*ez*fP2+1-ey*ey+ez*ez+fP2*fP2*ez*ez)*theta2;
b9de75e1 310 fC32 += ez*zz1*xy*theta2;
311 fC33 += zz1*zz1*theta2;
312 fC42 += xz*ez*xy*theta2;
313 fC43 += xz*zz1*theta2;
314 fC44 += xz*xz*theta2;
982aff31 315 /*
316 //
317 //MI coeficints
318 Double_t dc22 = (1-ey*ey+xz*xz*fX*fX)*theta2;
319 Double_t dc32 = (xz*fX*zz1)*theta2;
320 Double_t dc33 = (zz1*zz1)*theta2;
321 Double_t dc42 = (xz*fX*xz)*theta2;
322 Double_t dc43 = (zz1*xz)*theta2;
323 Double_t dc44 = (xz*xz)*theta2;
324 fC22 += dc22;
325 fC32 += dc32;
326 fC33 += dc33;
327 fC42 += dc42;
328 fC43 += dc43;
329 fC44 += dc44;
330 */
73042f01 331 //Energy losses************************
332 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d*rho;
333 if (x1 < x2) dE=-dE;
b9de75e1 334 cc=fP4;
982aff31 335
336 //Double_t E = sqrt(p2+GetMass()*GetMass());
337 //Double_t mifac = TMath::Sqrt(1.+dE*dE/p2+2*E*dE/p2)-1;
338 //Double_t belfac = E*dE/p2;
339 //
7f6ddf58 340 fP4*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
b9de75e1 341 fP2+=fX*(fP4-cc);
73042f01 342
e3f7105e 343 // Integrated Time [SR, GSI, 17.02.2003]
0fa7dfa7 344 if (x1 < x2)
345 if (IsStartedTimeIntegral()) {
e3f7105e 346 Double_t l2 = (fX-oldX)*(fX-oldX)+(fP0-oldY)*(fP0-oldY)+(fP1-oldZ)*(fP1-oldZ);
347 AddTimeStep(TMath::Sqrt(l2));
348 }
349 //
350
73042f01 351 return 1;
352}
353
354//_____________________________________________________________________________
7f6ddf58 355Int_t AliTPCtrack::PropagateToVertex(Double_t x0,Double_t rho)
73042f01 356{
357 //-----------------------------------------------------------------
358 // This function propagates tracks to the "vertex".
359 //-----------------------------------------------------------------
b9de75e1 360 Double_t c=fP4*fX - fP2;
361 Double_t tgf=-fP2/(fP4*fP0 + sqrt(1-c*c));
73042f01 362 Double_t snf=tgf/sqrt(1.+ tgf*tgf);
b9de75e1 363 Double_t xv=(fP2+snf)/fP4;
7f6ddf58 364 return PropagateTo(xv,x0,rho);
73042f01 365}
366
367//_____________________________________________________________________________
be9c5115 368Int_t AliTPCtrack::Update(const AliCluster *c, Double_t chisq, UInt_t index) {
73042f01 369 //-----------------------------------------------------------------
370 // This function associates a cluster with this track.
371 //-----------------------------------------------------------------
372 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
b19a0509 373 r00+=fC00; r01+=fC10; r11+=fC11;
73042f01 374 Double_t det=r00*r11 - r01*r01;
375 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
376
b19a0509 377 Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11;
378 Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11;
379 Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11;
380 Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11;
381 Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11;
73042f01 382
b19a0509 383 Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
b9de75e1 384 Double_t cur=fP4 + k40*dy + k41*dz, eta=fP2 + k20*dy + k21*dz;
1627d1c4 385 if (TMath::Abs(cur*fX-eta) >= 0.9) {
386 // Int_t n=GetNumberOfClusters();
387 //if (n>4) cerr<<n<<" AliTPCtrack warning: Filtering failed !\n";
be9c5115 388 return 0;
73042f01 389 }
390
b19a0509 391 fP0 += k00*dy + k01*dz;
392 fP1 += k10*dy + k11*dz;
393 fP2 = eta;
b9de75e1 394 fP3 += k30*dy + k31*dz;
395 fP4 = cur;
73042f01 396
b19a0509 397 Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40;
398 Double_t c12=fC21, c13=fC31, c14=fC41;
73042f01 399
b19a0509 400 fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11;
401 fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13;
402 fC40-=k00*c04+k01*c14;
73042f01 403
b19a0509 404 fC11-=k10*c01+k11*fC11;
405 fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13;
406 fC41-=k10*c04+k11*c14;
73042f01 407
b19a0509 408 fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13;
409 fC42-=k20*c04+k21*c14;
73042f01 410
b19a0509 411 fC33-=k30*c03+k31*c13;
b9de75e1 412 fC43-=k40*c03+k41*c13;
73042f01 413
b19a0509 414 fC44-=k40*c04+k41*c14;
73042f01 415
be9c5115 416 Int_t n=GetNumberOfClusters();
417 fIndex[n]=index;
418 SetNumberOfClusters(n+1);
419 SetChi2(GetChi2()+chisq);
420
421 return 1;
73042f01 422}
423
424//_____________________________________________________________________________
425Int_t AliTPCtrack::Rotate(Double_t alpha)
426{
427 //-----------------------------------------------------------------
428 // This function rotates this track.
429 //-----------------------------------------------------------------
430 fAlpha += alpha;
be9c5115 431 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
432 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
73042f01 433
b19a0509 434 Double_t x1=fX, y1=fP0;
73042f01 435 Double_t ca=cos(alpha), sa=sin(alpha);
b9de75e1 436 Double_t r1=fP4*fX - fP2;
73042f01 437
438 fX = x1*ca + y1*sa;
b19a0509 439 fP0=-x1*sa + y1*ca;
b9de75e1 440 fP2=fP2*ca + (fP4*y1 + sqrt(1.- r1*r1))*sa;
73042f01 441
b9de75e1 442 Double_t r2=fP4*fX - fP2;
73042f01 443 if (TMath::Abs(r2) >= 0.99999) {
be9c5115 444 Int_t n=GetNumberOfClusters();
445 if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !\n";
73042f01 446 return 0;
447 }
448
b9de75e1 449 Double_t y0=fP0 + sqrt(1.- r2*r2)/fP4;
450 if ((fP0-y0)*fP4 >= 0.) {
be9c5115 451 Int_t n=GetNumberOfClusters();
452 if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !!!\n";
73042f01 453 return 0;
454 }
455
456 //f = F - 1
b9de75e1 457 Double_t f00=ca-1, f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa,
458 f20=fP4*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1;
73042f01 459
460 //b = C*ft
b9de75e1 461 Double_t b00=fC00*f00, b02=fC00*f20+fC40*f24+fC20*f22;
462 Double_t b10=fC10*f00, b12=fC10*f20+fC41*f24+fC21*f22;
463 Double_t b20=fC20*f00, b22=fC20*f20+fC42*f24+fC22*f22;
464 Double_t b30=fC30*f00, b32=fC30*f20+fC43*f24+fC32*f22;
465 Double_t b40=fC40*f00, b42=fC40*f20+fC44*f24+fC42*f22;
73042f01 466
467 //a = f*b = f*C*ft
b9de75e1 468 Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22;
73042f01 469
470 // *** Double_t dy2=fCyy;
471
472 //F*C*Ft = C + (a + b + bt)
b19a0509 473 fC00 += a00 + 2*b00;
474 fC10 += b10;
475 fC20 += a02+b20+b02;
476 fC30 += b30;
477 fC40 += b40;
478 fC21 += b12;
479 fC32 += b32;
480 fC22 += a22 + 2*b22;
481 fC42 += b42;
73042f01 482
483 // *** fCyy+=dy2*sa*sa*r1*r1/(1.- r1*r1);
484 // *** fCzz+=d2y*sa*sa*fT*fT/(1.- r1*r1);
485
486 return 1;
487}
488
b9de75e1 489void AliTPCtrack::ResetCovariance() {
490 //------------------------------------------------------------------
491 //This function makes a track forget its history :)
492 //------------------------------------------------------------------
493
494 fC00*=10.;
495 fC10=0.; fC11*=10.;
496 fC20=0.; fC21=0.; fC22*=10.;
497 fC30=0.; fC31=0.; fC32=0.; fC33*=10.;
498 fC40=0.; fC41=0.; fC42=0.; fC43=0.; fC44*=10.;
499
73042f01 500}
77e58468 501
502////////////////////////////////////////////////////////////////////////
503Double_t AliTPCtrack::Phi() const {
7c27857f 504//
505//
506//
77e58468 507 Double_t phi = TMath::ASin(GetSnp()) + fAlpha;
508 if (phi<0) phi+=2*TMath::Pi();
509 if (phi>=2*TMath::Pi()) phi-=2*TMath::Pi();
510 return phi;
511}
512////////////////////////////////////////////////////////////////////////
513
51584047 514
515
516////////////////////////////////////////////////////////////////////////
517// MI ADDITION
518
519Float_t AliTPCtrack::Density(Int_t row0, Int_t row1)
520{
521 //
522 // calculate cluster density
523 Int_t good = 0;
524 Int_t found = 0;
525 //if (row0<fFirstPoint) row0 = fFirstPoint;
526 if (row1>fLastPoint) row1 = fLastPoint;
527
528
529 for (Int_t i=row0;i<=row1;i++){
530 // Int_t index = fClusterIndex[i];
531 Int_t index = fIndex[i];
532 if (index!=-1) good++;
533 if (index>0) found++;
534 }
535 Float_t density=0;
536 if (good>0) density = Float_t(found)/Float_t(good);
537 return density;
538}
539
540
541Float_t AliTPCtrack::Density2(Int_t row0, Int_t row1)
542{
543 //
544 // calculate cluster density
545 Int_t good = 0;
546 Int_t found = 0;
547 //
548 for (Int_t i=row0;i<=row1;i++){
549 Int_t index = fIndex[i];
550 if (index!=-1) good++;
551 if (index>0) found++;
552 }
553 Float_t density=0;
554 if (good>0) density = Float_t(found)/Float_t(good);
555 return density;
556}
557
558
559Double_t AliTPCtrack::GetZat0() const
560{
561 //
562 // return virtual z - supposing that x = 0
563 if (TMath::Abs(fP2)>1) return 0;
564 if (TMath::Abs(fX*fP4-fP2)>1) return 0;
565 Double_t vz = fP1+fP3/fP4*(asin(-fP2)-asin(fX*fP4-fP2));
566 return vz;
567}
568
569
570Double_t AliTPCtrack::GetD(Double_t x, Double_t y) const {
571 //------------------------------------------------------------------
572 // This function calculates the transverse impact parameter
573 // with respect to a point with global coordinates (x,y)
574 //------------------------------------------------------------------
575 //Double_t xt=fX, yt=fP0;
576
577 Double_t sn=TMath::Sin(fAlpha), cs=TMath::Cos(fAlpha);
578 Double_t a = x*cs + y*sn;
579 y = -x*sn + y*cs; x=a;
580 //
581 Double_t r = TMath::Abs(1/fP4);
582 Double_t x0 = TMath::Abs(fP2*r);
583 Double_t y0 = fP0;
584 y0= fP0+TMath::Sqrt(1-(fP4*fX-fP2)*(fP4*fX-fP2))/fP4;
585
586 Double_t delta = TMath::Sqrt((x-x0)*(x-x0)+(y-y0)*(y-y0));
587 // Double_t delta = TMath::Sqrt(TMath::Abs(x*x-2*x0*x+x0*x0+ y*y-2*y*y0+y0*y0));
588 delta -= TMath::Abs(r);
589 return delta;
590}
51ad6848 591
592//
593//
594
595void AliTPCtrack::UpdatePoints()
596{
597 //--------------------------------------------------
598 //calculates first ,amx dens and last points
599 //--------------------------------------------------
600 Float_t density[160];
601 for (Int_t i=0;i<160;i++) density[i]=-1.;
602 fPoints[0]= 160;
603 fPoints[1] = -1;
604 //
605 Int_t ngood=0;
606 Int_t undeff=0;
607 Int_t nall =0;
608 Int_t range=20;
609 for (Int_t i=0;i<160;i++){
610 Int_t last = i-range;
611 if (nall<range) nall++;
612 if (last>=0){
613 if (fIndex[last]>0&& (fIndex[last]&0x8000)==0) ngood--;
614 if (fIndex[last]==-1) undeff--;
615 }
616 if (fIndex[i]>0&& (fIndex[i]&0x8000)==0) ngood++;
617 if (fIndex[i]==-1) undeff++;
618 if (nall==range &&undeff<range/2) density[i-range/2] = Float_t(ngood)/Float_t(nall-undeff);
619 }
620 Float_t maxdens=0;
621 Int_t indexmax =0;
622 for (Int_t i=0;i<160;i++){
623 if (density[i]<0) continue;
624 if (density[i]>maxdens){
625 maxdens=density[i];
626 indexmax=i;
627 }
628 }
629 //
630 //max dens point
631 fPoints[3] = maxdens;
632 fPoints[1] = indexmax;
633 //
634 // last point
635 for (Int_t i=indexmax;i<160;i++){
636 if (density[i]<0) continue;
637 if (density[i]<maxdens/2.) {
638 break;
639 }
640 fPoints[2]=i;
641 }
642 //
643 // first point
644 for (Int_t i=indexmax;i>0;i--){
645 if (density[i]<0) continue;
646 if (density[i]<maxdens/2.) {
647 break;
648 }
649 fPoints[0]=i;
650 }
651 //
652}