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46d29e70 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
16/*
17$Log$
0e9c2ad5 18Revision 1.2 2000/10/06 16:49:46 cblume
19Made Getters const
20
46d29e70 21Revision 1.1.2.1 2000/09/22 14:47:52 cblume
22Add the tracking code
23
24*/
25
26#include <iostream.h>
27
28#include <TObject.h>
29
30#include "AliTRD.h"
46d29e70 31#include "AliTRDgeometry.h"
32#include "AliTRDcluster.h"
33#include "AliTRDtrack.h"
34
35ClassImp(AliTRDtrack)
36
37
38//_____________________________________________________________________________
39
40AliTRDtrack::AliTRDtrack(UInt_t index, const Double_t xx[5],
41const Double_t cc[15], Double_t xref, Double_t alpha) {
42 //-----------------------------------------------------------------
43 // This is the main track constructor.
44 //-----------------------------------------------------------------
45 fLab=-1;
46 fChi2=0.;
47 fdEdx=0.;
48
49 fAlpha=alpha;
50 fX=xref;
51
52 fY=xx[0]; fZ=xx[1]; fC=xx[2]; fE=xx[3]; fT=xx[4];
53
54 fCyy=cc[0];
55 fCzy=cc[1]; fCzz=cc[2];
56 fCcy=cc[3]; fCcz=cc[4]; fCcc=cc[5];
57 fCey=cc[6]; fCez=cc[7]; fCec=cc[8]; fCee=cc[9];
58 fCty=cc[10]; fCtz=cc[11]; fCtc=cc[12]; fCte=cc[13]; fCtt=cc[14];
59
60 fN=0;
61 fIndex[fN++]=index;
62}
63
64//_____________________________________________________________________________
65AliTRDtrack::AliTRDtrack(const AliTRDtrack& t) {
66 //
67 // Copy constructor.
68 //
69
70 fLab=t.fLab;
71
72 fChi2=t.fChi2;
73 fdEdx=t.fdEdx;
74
75 fAlpha=t.fAlpha;
76 fX=t.fX;
77
78 fY=t.fY; fZ=t.fZ; fC=t.fC; fE=t.fE; fT=t.fT;
79
80 fCyy=t.fCyy;
81 fCzy=t.fCzy; fCzz=t.fCzz;
82 fCcy=t.fCcy; fCcz=t.fCcz; fCcc=t.fCcc;
83 fCey=t.fCey; fCez=t.fCez; fCec=t.fCec; fCee=t.fCee;
84 fCty=t.fCty; fCtz=t.fCtz; fCtc=t.fCtc; fCte=t.fCte; fCtt=t.fCtt;
85
86 fN=t.fN;
87 for (Int_t i=0; i<fN; i++) fIndex[i]=t.fIndex[i];
88}
89
90//_____________________________________________________________________________
91void AliTRDtrack::GetCovariance(Double_t cc[15]) const {
92 cc[0]=fCyy;
93 cc[1]=fCzy; cc[2]=fCzz;
94 cc[3]=fCcy; cc[4]=fCcz; cc[5]=fCcc;
95 cc[6]=fCey; cc[7]=fCez; cc[8]=fCec; cc[9]=fCee;
96 cc[10]=fCty; cc[11]=fCtz; cc[12]=fCtc; cc[13]=fCte; cc[14]=fCtt;
97}
98
99//_____________________________________________________________________________
100Int_t AliTRDtrack::Compare(TObject *o) {
101
102// Compares tracks according to their Y2
103
104 AliTRDtrack *t=(AliTRDtrack*)o;
105 // Double_t co=t->GetSigmaY2();
106 // Double_t c =GetSigmaY2();
107
108 Double_t co=TMath::Abs(t->GetC());
109 Double_t c =TMath::Abs(GetC());
110
111 if (c>co) return 1;
112 else if (c<co) return -1;
113 return 0;
114}
115
116//_____________________________________________________________________________
117Int_t AliTRDtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho,Double_t pm)
118{
119 // Propagates a track of particle with mass=pm to a reference plane
120 // defined by x=xk through media of density=rho and radiationLength=x0
121
122 if (TMath::Abs(fC*xk - fE) >= 0.99999) {
123 if (fN>4) cerr<<fN<<" AliTRDtrack warning: Propagation failed !\n";
124 return 0;
125 }
126
127 Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fY, z1=fZ;
128 Double_t c1=fC*x1 - fE, r1=sqrt(1.- c1*c1);
129 Double_t c2=fC*x2 - fE, r2=sqrt(1.- c2*c2);
130
131 fY += dx*(c1+c2)/(r1+r2);
132 fZ += dx*(c1+c2)/(c1*r2 + c2*r1)*fT;
133
134 //f = F - 1
135 Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
136 Double_t f02= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
137 Double_t f03=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
138 Double_t cr=c1*r2+c2*r1;
139 Double_t f12= dx*fT*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);
140 Double_t f13=-dx*fT*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
141 Double_t f14= dx*cc/cr;
142
143 //b = C*ft
144 Double_t b00=f02*fCcy + f03*fCey, b01=f12*fCcy + f13*fCey + f14*fCty;
145 Double_t b10=f02*fCcz + f03*fCez, b11=f12*fCcz + f13*fCez + f14*fCtz;
146 Double_t b20=f02*fCcc + f03*fCec, b21=f12*fCcc + f13*fCec + f14*fCtc;
147 Double_t b30=f02*fCec + f03*fCee, b31=f12*fCec + f13*fCee + f14*fCte;
148 Double_t b40=f02*fCtc + f03*fCte, b41=f12*fCtc + f13*fCte + f14*fCtt;
149
150 //a = f*b = f*C*ft
151 Double_t a00=f02*b20+f03*b30,a01=f02*b21+f03*b31,a11=f12*b21+f13*b31+f14*b41;
152
153 //F*C*Ft = C + (a + b + bt)
154 fCyy += a00 + 2*b00;
155 fCzy += a01 + b01 + b10;
156 fCcy += b20;
157 fCey += b30;
158 fCty += b40;
159 fCzz += a11 + 2*b11;
160 fCcz += b21;
161 fCez += b31;
162 fCtz += b41;
163
164 fX=x2;
165
166
167 //Multiple scattering ******************
168
169 Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fY)*(y1-fY)+(z1-fZ)*(z1-fZ));
170 Double_t p2=GetPt()*GetPt()*(1.+fT*fT);
171 Double_t beta2=p2/(p2 + pm*pm);
172
173 Double_t ey=fC*fX - fE, ez=fT;
174 Double_t xz=fC*ez, zz1=ez*ez+1, xy=fE+ey;
175
176 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
177 fCcc += xz*xz*theta2;
178 fCec += xz*ez*xy*theta2;
179 fCtc += xz*zz1*theta2;
180 fCee += (2*ey*ez*ez*fE+1-ey*ey+ez*ez+fE*fE*ez*ez)*theta2;
181 fCte += ez*zz1*xy*theta2;
182 fCtt += zz1*zz1*theta2;
183
184
185 //Energy losses************************
186
187 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d*rho;
188 if (x1 < x2) dE=-dE;
189 fC*=(1.- sqrt(p2+pm*pm)/p2*dE);
190 //fE*=(1.- sqrt(p2+pm*pm)/p2*dE);
191
192 return 1;
193
194}
195
196
197//_____________________________________________________________________________
198void AliTRDtrack::PropagateToVertex(Double_t x0,Double_t rho,Double_t pm)
199{
200 // This function propagates tracks to the "vertex".
201
202 Double_t c=fC*fX - fE;
203 Double_t tgf=-fE/(fC*fY + sqrt(1-c*c));
204 Double_t snf=tgf/sqrt(1.+ tgf*tgf);
205 Double_t xv=(fE+snf)/fC;
206 PropagateTo(xv,x0,rho,pm);
207}
208
209
210//_____________________________________________________________________________
211void AliTRDtrack::Update(const AliTRDcluster *c, Double_t chisq, UInt_t index)
212{
213 // Assignes found cluster to the track and updates track information
214
215 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2()*12;
216 r00+=fCyy; r01+=fCzy; r11+=fCzz;
217 Double_t det=r00*r11 - r01*r01;
218 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
219
220 Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
221 Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
222 Double_t k20=fCcy*r00+fCcz*r01, k21=fCcy*r01+fCcz*r11;
223 Double_t k30=fCey*r00+fCez*r01, k31=fCey*r01+fCez*r11;
224 Double_t k40=fCty*r00+fCtz*r01, k41=fCty*r01+fCtz*r11;
225
226 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
227 Double_t cur=fC + k20*dy + k21*dz, eta=fE + k30*dy + k31*dz;
228 if (TMath::Abs(cur*fX-eta) >= 0.99999) {
229 if (fN>4) cerr<<fN<<" AliTRDtrack warning: Filtering failed !\n";
230 return;
231 }
232
233 fY += k00*dy + k01*dz;
234 fZ += k10*dy + k11*dz;
235 fC = cur;
236 fE = eta;
237 fT += k40*dy + k41*dz;
238
239 Double_t c01=fCzy, c02=fCcy, c03=fCey, c04=fCty;
240 Double_t c12=fCcz, c13=fCez, c14=fCtz;
241
242 fCyy-=k00*fCyy+k01*fCzy; fCzy-=k00*c01+k01*fCzz;
243 fCcy-=k00*c02+k01*c12; fCey-=k00*c03+k01*c13;
244 fCty-=k00*c04+k01*c14;
245
246 fCzz-=k10*c01+k11*fCzz;
247 fCcz-=k10*c02+k11*c12; fCez-=k10*c03+k11*c13;
248 fCtz-=k10*c04+k11*c14;
249
250 fCcc-=k20*c02+k21*c12; fCec-=k20*c03+k21*c13;
251 fCtc-=k20*c04+k21*c14;
252
253 fCee-=k30*c03+k31*c13;
254 fCte-=k30*c04+k31*c14;
255
256 fCtt-=k40*c04+k41*c14;
257
258 fIndex[fN++]=index;
259 fChi2 += chisq;
260
261 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
262}
263
264//_____________________________________________________________________________
265Int_t AliTRDtrack::Rotate(Double_t alpha)
266{
267 // Rotates track parameters in R*phi plane
268
269 fAlpha += alpha;
270
271 Double_t x1=fX, y1=fY;
272 Double_t ca=cos(alpha), sa=sin(alpha);
273 Double_t r1=fC*fX - fE;
274
275 fX = x1*ca + y1*sa;
276 fY=-x1*sa + y1*ca;
277 fE=fE*ca + (fC*y1 + sqrt(1.- r1*r1))*sa;
278
279 Double_t r2=fC*fX - fE;
280 if (TMath::Abs(r2) >= 0.99999) {
281 if (fN>4) cerr<<fN<<" AliTRDtrack warning: Rotation failed !\n";
282 return 0;
283 }
284
285 Double_t y0=fY + sqrt(1.- r2*r2)/fC;
286 if ((fY-y0)*fC >= 0.) {
287 if (fN>4) cerr<<fN<<" AliTRDtrack warning: Rotation failed !!!\n";
288 return 0;
289 }
290
291 //f = F - 1
292 Double_t f00=ca-1, f32=(y1 - r1*x1/sqrt(1.- r1*r1))*sa,
293 f30=fC*sa, f33=(ca + sa*r1/sqrt(1.- r1*r1))-1;
294
295 //b = C*ft
296 Double_t b00=fCyy*f00, b03=fCyy*f30+fCcy*f32+fCey*f33;
297 Double_t b10=fCzy*f00, b13=fCzy*f30+fCcz*f32+fCez*f33;
298 Double_t b20=fCcy*f00, b23=fCcy*f30+fCcc*f32+fCec*f33;
299 Double_t b30=fCey*f00, b33=fCey*f30+fCec*f32+fCee*f33;
300 Double_t b40=fCty*f00, b43=fCty*f30+fCtc*f32+fCte*f33;
301
302 //a = f*b = f*C*ft
303 Double_t a00=f00*b00, a03=f00*b03, a33=f30*b03+f32*b23+f33*b33;
304
305 // *** Double_t dy2=fCyy;
306
307 //F*C*Ft = C + (a + b + bt)
308 fCyy += a00 + 2*b00;
309 fCzy += b10;
310 fCcy += b20;
311 fCey += a03+b30+b03;
312 fCty += b40;
313 fCez += b13;
314 fCec += b23;
315 fCee += a33 + 2*b33;
316 fCte += b43;
317
318 // *** fCyy+=dy2*sa*sa*r1*r1/(1.- r1*r1);
319 // *** fCzz+=d2y*sa*sa*fT*fT/(1.- r1*r1);
320
321 return 1;
322}
323
324
325
326
327//_____________________________________________________________________________
328Double_t AliTRDtrack::GetPredictedChi2(const AliTRDcluster *c) const
329{
330 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2()*12;
331 r00+=fCyy; r01+=fCzy; r11+=fCzz;
332
333 Double_t det=r00*r11 - r01*r01;
334 if (TMath::Abs(det) < 1.e-10) {
335 if (fN>4) cerr<<fN<<" AliTRDtrack warning: Singular matrix !\n";
336 return 1e10;
337 }
338 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
339
340 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
341
342 return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
343}
344
345
346//_________________________________________________________________________
347void AliTRDtrack::GetPxPyPz(Double_t& px, Double_t& py, Double_t& pz) const
348{
349 // Returns reconstructed track momentum in the global system.
350
351 Double_t pt=TMath::Abs(GetPt()); // GeV/c
352 Double_t r=fC*fX-fE;
353 Double_t y0=fY + sqrt(1.- r*r)/fC;
354 px=-pt*(fY-y0)*fC; //cos(phi);
355 py=-pt*(fE-fX*fC); //sin(phi);
356 pz=pt*fT;
357 Double_t tmp=px*TMath::Cos(fAlpha) - py*TMath::Sin(fAlpha);
358 py=px*TMath::Sin(fAlpha) + py*TMath::Cos(fAlpha);
359 px=tmp;
360
361}
362
363//____________________________________________________________________________
364void AliTRDtrack::Streamer(TBuffer &R__b)
365{
366 if (R__b.IsReading()) {
367 Version_t R__v = R__b.ReadVersion(); if (R__v) { }
368 TObject::Streamer(R__b);
369 R__b >> fLab;
370 R__b >> fChi2;
371 R__b >> fdEdx;
372 R__b >> fAlpha;
373 R__b >> fX;
374 R__b >> fY;
375 R__b >> fZ;
376 R__b >> fC;
377 R__b >> fE;
378 R__b >> fT;
379 R__b >> fCyy;
380 R__b >> fCzy;
381 R__b >> fCzz;
382 R__b >> fCcy;
383 R__b >> fCcz;
384 R__b >> fCcc;
385 R__b >> fCey;
386 R__b >> fCez;
387 R__b >> fCec;
388 R__b >> fCee;
389 R__b >> fCty;
390 R__b >> fCtz;
391 R__b >> fCtc;
392 R__b >> fCte;
393 R__b >> fCtt;
394 R__b >> fN;
395 for (Int_t i=0; i<fN; i++) R__b >> fIndex[i];
396 } else {
397 R__b.WriteVersion(AliTRDtrack::IsA());
398 TObject::Streamer(R__b);
399 R__b << fLab;
400 R__b << fChi2;
401 R__b << fdEdx;
402 R__b << fAlpha;
403 R__b << fX;
404 R__b << fY;
405 R__b << fZ;
406 R__b << fC;
407 R__b << fE;
408 R__b << fT;
409 R__b << fCyy;
410 R__b << fCzy;
411 R__b << fCzz;
412 R__b << fCcy;
413 R__b << fCcz;
414 R__b << fCcc;
415 R__b << fCey;
416 R__b << fCez;
417 R__b << fCec;
418 R__b << fCee;
419 R__b << fCty;
420 R__b << fCtz;
421 R__b << fCtc;
422 R__b << fCte;
423 R__b << fCtt;
424 R__b << fN;
425 for (Int_t i=0; i<fN; i++) R__b << fIndex[i];
426 }
427}
428
429//_____________________________________________________________________________
430void AliTRDseed::CookdEdx(Double_t low, Double_t up) {
431
432 // Calculates dE/dX within the "low" and "up" cuts.
433
434 Int_t i;
435 Int_t nc=this->GetNclusters();
436
437 Int_t swap;//stupid sorting
438 do {
439 swap=0;
440 for (i=0; i<nc-1; i++) {
441 if (fdEdx[i]<=fdEdx[i+1]) continue;
442 Float_t tmp=fdEdx[i]; fdEdx[i]=fdEdx[i+1]; fdEdx[i+1]=tmp;
443 swap++;
444 }
445 } while (swap);
446
447 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc);
448 Float_t dedx=0;
449 for (i=nl; i<=nu; i++) dedx += fdEdx[i];
450 dedx /= (nu-nl+1);
451 SetdEdx(dedx);
452}
453