1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
18 Revision 1.14 2002/11/07 15:52:09 cblume
19 Update of tracking code for tilted pads
21 Revision 1.13 2002/10/22 15:53:08 alibrary
22 Introducing Riostream.h
24 Revision 1.12 2002/10/14 14:57:44 hristov
25 Merging the VirtualMC branch to the main development branch (HEAD)
27 Revision 1.8.10.2 2002/07/24 10:09:31 alibrary
30 RRevision 1.11 2002/06/13 12:09:58 hristov
33 Revision 1.10 2002/06/12 09:54:35 cblume
34 Update of tracking code provided by Sergei
36 Revision 1.8 2001/05/30 12:17:47 hristov
37 Loop variables declared once
39 Revision 1.7 2001/05/28 17:07:58 hristov
40 Last minute changes; ExB correction in AliTRDclusterizerV1; taking into account of material in G10 TEC frames and material between TEC planes (C.Blume,S.Sedykh)
42 Revision 1.4 2000/12/08 16:07:02 cblume
43 Update of the tracking by Sergei
45 Revision 1.3 2000/10/15 23:40:01 cblume
48 Revision 1.2 2000/10/06 16:49:46 cblume
51 Revision 1.1.2.1 2000/09/22 14:47:52 cblume
56 #include <Riostream.h>
59 #include "AliTRDgeometry.h"
60 #include "AliTRDcluster.h"
61 #include "AliTRDtrack.h"
62 #include "../TPC/AliTPCtrack.h"
68 //_____________________________________________________________________________
70 AliTRDtrack::AliTRDtrack(const AliTRDcluster *c, UInt_t index,
71 const Double_t xx[5], const Double_t cc[15],
72 Double_t xref, Double_t alpha) : AliKalmanTrack() {
73 //-----------------------------------------------------------------
74 // This is the main track constructor.
75 //-----------------------------------------------------------------
80 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
81 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
85 fY=xx[0]; fZ=xx[1]; fE=xx[2]; fT=xx[3]; fC=xx[4];
88 fCzy=cc[1]; fCzz=cc[2];
89 fCey=cc[3]; fCez=cc[4]; fCee=cc[5];
90 fCty=cc[6]; fCtz=cc[7]; fCte=cc[8]; fCtt=cc[9];
91 fCcy=cc[10]; fCcz=cc[11]; fCce=cc[12]; fCct=cc[13]; fCcc=cc[14];
94 SetNumberOfClusters(1);
100 Double_t q = TMath::Abs(c->GetQ());
101 Double_t s = fX*fC - fE, t=fT;
102 if(s*s < 1) q *= TMath::Sqrt((1-s*s)/(1+t*t));
107 //_____________________________________________________________________________
108 AliTRDtrack::AliTRDtrack(const AliTRDtrack& t) : AliKalmanTrack(t) {
113 SetLabel(t.GetLabel());
114 fSeedLab=t.GetSeedLabel();
116 SetChi2(t.GetChi2());
124 fY=t.fY; fZ=t.fZ; fC=t.fC; fE=t.fE; fT=t.fT;
127 fCzy=t.fCzy; fCzz=t.fCzz;
128 fCey=t.fCey; fCez=t.fCez; fCee=t.fCee;
129 fCty=t.fCty; fCtz=t.fCtz; fCte=t.fCte; fCtt=t.fCtt;
130 fCcy=t.fCcy; fCcz=t.fCcz; fCce=t.fCce; fCct=t.fCct; fCcc=t.fCcc;
132 Int_t n=t.GetNumberOfClusters();
133 SetNumberOfClusters(n);
134 for (Int_t i=0; i<n; i++) {
135 fIndex[i]=t.fIndex[i];
140 //_____________________________________________________________________________
141 AliTRDtrack::AliTRDtrack(const AliKalmanTrack& t, Double_t alpha)
144 // Constructor from AliTPCtrack or AliITStrack .
147 SetLabel(t.GetLabel());
149 SetNumberOfClusters(0);
156 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
157 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
159 Double_t x, p[5]; t.GetExternalParameters(x,p);
171 //Conversion of the covariance matrix
172 Double_t c[15]; t.GetExternalCovariance(c);
174 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
176 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
177 Double_t c32=fX*c[13] - c[8];
178 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
181 fCzy=c[1]; fCzz=c[2];
182 fCey=c20; fCez=c21; fCee=c22;
183 fCty=c[6]; fCtz=c[7]; fCte=c32; fCtt=c[9];
184 fCcy=c[10]; fCcz=c[11]; fCce=c42; fCct=c[13]; fCcc=c[14];
188 //____________________________________________________________________________
189 void AliTRDtrack::GetExternalParameters(Double_t& xr, Double_t x[5]) const {
191 // This function returns external TRD track representation
198 x[4]=fC*GetConvConst();
201 //_____________________________________________________________________________
202 void AliTRDtrack::GetExternalCovariance(Double_t cc[15]) const {
204 // This function returns external representation of the covriance matrix.
206 Double_t a=GetConvConst();
208 Double_t c22=fX*fX*fCcc-2*fX*fCce+fCee;
209 Double_t c32=fX*fCct-fCte;
210 Double_t c20=fX*fCcy-fCey, c21=fX*fCcz-fCez, c42=fX*fCcc-fCce;
213 cc[1 ]=fCzy; cc[2 ]=fCzz;
214 cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22;
215 cc[6 ]=fCty; cc[7 ]=fCtz; cc[8 ]=c32; cc[9 ]=fCtt;
216 cc[10]=fCcy*a; cc[11]=fCcz*a; cc[12]=c42*a; cc[13]=fCct*a; cc[14]=fCcc*a*a;
220 //_____________________________________________________________________________
221 void AliTRDtrack::GetCovariance(Double_t cc[15]) const {
223 cc[1]=fCzy; cc[2]=fCzz;
224 cc[3]=fCey; cc[4]=fCez; cc[5]=fCee;
225 cc[6]=fCcy; cc[7]=fCcz; cc[8]=fCce; cc[9]=fCcc;
226 cc[10]=fCty; cc[11]=fCtz; cc[12]=fCte; cc[13]=fCct; cc[14]=fCtt;
229 //_____________________________________________________________________________
230 Int_t AliTRDtrack::Compare(const TObject *o) const {
232 // Compares tracks according to their Y2 or curvature
234 AliTRDtrack *t=(AliTRDtrack*)o;
235 // Double_t co=t->GetSigmaY2();
236 // Double_t c =GetSigmaY2();
238 Double_t co=TMath::Abs(t->GetC());
239 Double_t c =TMath::Abs(GetC());
242 else if (c<co) return -1;
246 //_____________________________________________________________________________
247 void AliTRDtrack::CookdEdx(Double_t low, Double_t up) {
248 //-----------------------------------------------------------------
249 // Calculates dE/dX within the "low" and "up" cuts.
250 //-----------------------------------------------------------------
253 Int_t nc=GetNumberOfClusters();
255 Float_t sorted[kMAX_CLUSTERS_PER_TRACK];
256 for (i=0; i < nc; i++) {
264 for (i=0; i<nc-1; i++) {
265 if (sorted[i]<=sorted[i+1]) continue;
266 Float_t tmp=sorted[i];
267 sorted[i]=sorted[i+1]; sorted[i+1]=tmp;
272 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc);
274 for (i=nl; i<=nu; i++) dedx += sorted[i];
283 //_____________________________________________________________________________
284 Int_t AliTRDtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho)
286 // Propagates a track of particle with mass=pm to a reference plane
287 // defined by x=xk through media of density=rho and radiationLength=x0
290 if (TMath::Abs(fC*xk - fE) >= 0.99999) {
291 Int_t n=GetNumberOfClusters();
292 if (n>4) cerr<<n<<" AliTRDtrack warning: Propagation failed !\n";
296 Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fY, z1=fZ;
297 Double_t c1=fC*x1 - fE;
298 if((c1*c1) > 1) return 0;
299 Double_t r1=sqrt(1.- c1*c1);
300 Double_t c2=fC*x2 - fE;
301 if((c2*c2) > 1) return 0;
302 Double_t r2=sqrt(1.- c2*c2);
304 fY += dx*(c1+c2)/(r1+r2);
305 fZ += dx*(c1+c2)/(c1*r2 + c2*r1)*fT;
308 Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
309 Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
310 Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
311 Double_t cr=c1*r2+c2*r1;
312 Double_t f12=-dx*fT*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
313 Double_t f13= dx*cc/cr;
314 Double_t f14= dx*fT*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);
317 Double_t b00=f02*fCey + f04*fCcy, b01=f12*fCey + f14*fCcy + f13*fCty;
318 Double_t b10=f02*fCez + f04*fCcz, b11=f12*fCez + f14*fCcz + f13*fCtz;
319 Double_t b20=f02*fCee + f04*fCce, b21=f12*fCee + f14*fCce + f13*fCte;
320 Double_t b30=f02*fCte + f04*fCct, b31=f12*fCte + f14*fCct + f13*fCtt;
321 Double_t b40=f02*fCce + f04*fCcc, b41=f12*fCce + f14*fCcc + f13*fCct;
324 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31;
326 //F*C*Ft = C + (a + b + bt)
328 fCzy += a01 + b01 + b10;
340 //Multiple scattering ******************
342 Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fY)*(y1-fY)+(z1-fZ)*(z1-fZ));
343 Double_t p2=GetPt()*GetPt()*(1.+fT*fT);
344 p2 = TMath::Min(p2,1e+08); // to avoid division by (1-1) for stiff tracks
345 Double_t beta2=p2/(p2 + GetMass()*GetMass());
347 Double_t ey=fC*fX - fE, ez=fT;
348 Double_t xz=fC*ez, zz1=ez*ez+1, xy=fE+ey;
350 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
352 fCee += (2*ey*ez*ez*fE+1-ey*ey+ez*ez+fE*fE*ez*ez)*theta2;
353 fCte += ez*zz1*xy*theta2;
354 fCtt += zz1*zz1*theta2;
355 fCce += xz*ez*xy*theta2;
356 fCct += xz*zz1*theta2;
357 fCcc += xz*xz*theta2;
360 //Energy losses************************
362 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d*rho;
363 //PH SetLength(GetLength()+d);
366 fC*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
374 //_____________________________________________________________________________
375 Int_t AliTRDtrack::Update(const AliTRDcluster *c, Double_t chisq, UInt_t index, Double_t h01)
377 // Assignes found cluster to the track and updates track information
380 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2()*100.0;
382 r00+=(fCyy+2.0*h01*fCzy+h01*h01*fCzz);
383 r01+=(fCzy+h01*fCzz);
386 Double_t det=r00*r11 - r01*r01;
387 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
389 // Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
390 // Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
391 // Double_t k20=fCey*r00+fCez*r01, k21=fCey*r01+fCez*r11;
392 // Double_t k30=fCty*r00+fCtz*r01, k31=fCty*r01+fCtz*r11;
393 // Double_t k40=fCcy*r00+fCcz*r01, k41=fCcy*r01+fCcz*r11;
395 Double_t k00=fCyy*r00+fCzy*(r01+h01*r00),k01=fCyy*r01+fCzy*(r11+h01*r01);
396 Double_t k10=fCzy*r00+fCzz*(r01+h01*r00),k11=fCzy*r01+fCzz*(r11+h01*r01);
397 Double_t k20=fCey*r00+fCez*(r01+h01*r00),k21=fCey*r01+fCez*(r11+h01*r01);
398 Double_t k30=fCty*r00+fCtz*(r01+h01*r00),k31=fCty*r01+fCtz*(r11+h01*r01);
399 Double_t k40=fCcy*r00+fCcz*(r01+h01*r00),k41=fCcy*r01+fCcz*(r11+h01*r01);
401 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
405 Double_t cur=fC + k40*dy + k41*dz, eta=fE + k20*dy + k21*dz;
406 if (TMath::Abs(cur*fX-eta) >= 0.99999) {
407 Int_t n=GetNumberOfClusters();
408 if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
412 fY += k00*dy + k01*dz;
413 fZ += k10*dy + k11*dz;
415 fT += k30*dy + k31*dz;
425 Double_t c01=fCzy, c02=fCey, c03=fCty, c04=fCcy;
426 Double_t c12=fCez, c13=fCtz, c14=fCcz;
428 fCyy-=k00*fCyy+k01*fCzy; fCzy-=k00*c01+k01*fCzz;
429 fCey-=k00*c02+k01*c12; fCty-=k00*c03+k01*c13;
430 fCcy-=k00*c04+k01*c14;
432 fCzz-=k10*c01+k11*fCzz;
433 fCez-=k10*c02+k11*c12; fCtz-=k10*c03+k11*c13;
434 fCcz-=k10*c04+k11*c14;
436 fCee-=k20*c02+k21*c12; fCte-=k20*c03+k21*c13;
437 fCce-=k20*c04+k21*c14;
439 fCtt-=k30*c03+k31*c13;
440 fCct-=k40*c03+k41*c13;
442 fCcc-=k40*c04+k41*c14;
444 Int_t n=GetNumberOfClusters();
446 SetNumberOfClusters(n+1);
448 SetChi2(GetChi2()+chisq);
450 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
457 //_____________________________________________________________________________
458 Int_t AliTRDtrack::Rotate(Double_t alpha)
460 // Rotates track parameters in R*phi plane
463 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
464 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
466 Double_t x1=fX, y1=fY;
467 Double_t ca=cos(alpha), sa=sin(alpha);
468 Double_t r1=fC*fX - fE;
470 if (TMath::Abs(r1) >= 0.99999) {
471 Int_t n=GetNumberOfClusters();
472 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !\n";
478 fE=fE*ca + (fC*y1 + sqrt(1.- r1*r1))*sa;
480 Double_t r2=fC*fX - fE;
481 if (TMath::Abs(r2) >= 0.99999) {
482 Int_t n=GetNumberOfClusters();
483 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !\n";
487 Double_t y0=fY + sqrt(1.- r2*r2)/fC;
488 if ((fY-y0)*fC >= 0.) {
489 Int_t n=GetNumberOfClusters();
490 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !!!\n";
495 Double_t f00=ca-1, f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa,
496 f20=fC*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1;
499 Double_t b00=fCyy*f00, b02=fCyy*f20+fCcy*f24+fCey*f22;
500 Double_t b10=fCzy*f00, b12=fCzy*f20+fCcz*f24+fCez*f22;
501 Double_t b20=fCey*f00, b22=fCey*f20+fCce*f24+fCee*f22;
502 Double_t b30=fCty*f00, b32=fCty*f20+fCct*f24+fCte*f22;
503 Double_t b40=fCcy*f00, b42=fCcy*f20+fCcc*f24+fCce*f22;
506 Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22;
508 // *** Double_t dy2=fCyy;
510 //F*C*Ft = C + (a + b + bt)
521 // *** fCyy+=dy2*sa*sa*r1*r1/(1.- r1*r1);
522 // *** fCzz+=d2y*sa*sa*fT*fT/(1.- r1*r1);
528 //_____________________________________________________________________________
529 Double_t AliTRDtrack::GetPredictedChi2(const AliTRDcluster *c, Double_t h01) const
532 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
534 r00+=fCyy; r01+=fCzy; r11+=fCzz;
536 Double_t det=r00*r11 - r01*r01;
537 if (TMath::Abs(det) < 1.e-10) {
538 Int_t n=GetNumberOfClusters();
539 if (n>4) cerr<<n<<" AliTRDtrack warning: Singular matrix !\n";
542 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
544 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
548 return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
553 //_________________________________________________________________________
554 void AliTRDtrack::GetPxPyPz(Double_t& px, Double_t& py, Double_t& pz) const
556 // Returns reconstructed track momentum in the global system.
558 Double_t pt=TMath::Abs(GetPt()); // GeV/c
562 if(r > 1) { py = pt; px = 0; }
563 else if(r < -1) { py = -pt; px = 0; }
565 y0=fY + sqrt(1.- r*r)/fC;
566 px=-pt*(fY-y0)*fC; //cos(phi);
567 py=-pt*(fE-fX*fC); //sin(phi);
570 Double_t tmp=px*TMath::Cos(fAlpha) - py*TMath::Sin(fAlpha);
571 py=px*TMath::Sin(fAlpha) + py*TMath::Cos(fAlpha);
576 //_________________________________________________________________________
577 void AliTRDtrack::GetGlobalXYZ(Double_t& x, Double_t& y, Double_t& z) const
579 // Returns reconstructed track coordinates in the global system.
581 x = fX; y = fY; z = fZ;
582 Double_t tmp=x*TMath::Cos(fAlpha) - y*TMath::Sin(fAlpha);
583 y=x*TMath::Sin(fAlpha) + y*TMath::Cos(fAlpha);
588 //_________________________________________________________________________
589 void AliTRDtrack::ResetCovariance() {
591 // Resets covariance matrix
596 fCey=0.; fCez=0.; fCee*=10.;
597 fCty=0.; fCtz=0.; fCte=0.; fCtt*=10.;
598 fCcy=0.; fCcz=0.; fCce=0.; fCct=0.; fCcc*=10.;