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 1.17 2003/02/19 09:02:28 hristov
19 Track time measurement (S.Radomski)
21 Revision 1.16 2003/02/10 14:06:10 cblume
22 Add tracking without tilted pads as option
24 Revision 1.15 2003/01/27 16:34:49 cblume
25 Update of tracking by Sergei and Chuncheng
27 Revision 1.14 2002/11/07 15:52:09 cblume
28 Update of tracking code for tilted pads
30 Revision 1.13 2002/10/22 15:53:08 alibrary
31 Introducing Riostream.h
33 Revision 1.12 2002/10/14 14:57:44 hristov
34 Merging the VirtualMC branch to the main development branch (HEAD)
36 Revision 1.8.10.2 2002/07/24 10:09:31 alibrary
39 RRevision 1.11 2002/06/13 12:09:58 hristov
42 Revision 1.10 2002/06/12 09:54:35 cblume
43 Update of tracking code provided by Sergei
45 Revision 1.8 2001/05/30 12:17:47 hristov
46 Loop variables declared once
48 Revision 1.7 2001/05/28 17:07:58 hristov
49 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)
51 Revision 1.4 2000/12/08 16:07:02 cblume
52 Update of the tracking by Sergei
54 Revision 1.3 2000/10/15 23:40:01 cblume
57 Revision 1.2 2000/10/06 16:49:46 cblume
60 Revision 1.1.2.1 2000/09/22 14:47:52 cblume
65 #include <Riostream.h>
68 #include "AliTRDgeometry.h"
69 #include "AliTRDcluster.h"
70 #include "AliTRDtrack.h"
71 #include "../TPC/AliTPCtrack.h"
77 //_____________________________________________________________________________
79 AliTRDtrack::AliTRDtrack(const AliTRDcluster *c, UInt_t index,
80 const Double_t xx[5], const Double_t cc[15],
81 Double_t xref, Double_t alpha) : AliKalmanTrack() {
82 //-----------------------------------------------------------------
83 // This is the main track constructor.
84 //-----------------------------------------------------------------
89 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
90 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
94 fY=xx[0]; fZ=xx[1]; fE=xx[2]; fT=xx[3]; fC=xx[4];
97 fCzy=cc[1]; fCzz=cc[2];
98 fCey=cc[3]; fCez=cc[4]; fCee=cc[5];
99 fCty=cc[6]; fCtz=cc[7]; fCte=cc[8]; fCtt=cc[9];
100 fCcy=cc[10]; fCcz=cc[11]; fCce=cc[12]; fCct=cc[13]; fCcc=cc[14];
103 SetNumberOfClusters(1);
111 Double_t q = TMath::Abs(c->GetQ());
112 Double_t s = fX*fC - fE, t=fT;
113 if(s*s < 1) q *= TMath::Sqrt((1-s*s)/(1+t*t));
117 // initialisation [SR, GSI 18.02.2003] (i startd for 1)
118 for(Int_t i=1; i<kMAX_CLUSTERS_PER_TRACK; i++) {
124 //_____________________________________________________________________________
125 AliTRDtrack::AliTRDtrack(const AliTRDtrack& t) : AliKalmanTrack(t) {
130 SetLabel(t.GetLabel());
131 fSeedLab=t.GetSeedLabel();
133 SetChi2(t.GetChi2());
138 fNRotate = t.fNRotate;
143 fY=t.fY; fZ=t.fZ; fE=t.fE; fT=t.fT; fC=t.fC;
146 fCzy=t.fCzy; fCzz=t.fCzz;
147 fCey=t.fCey; fCez=t.fCez; fCee=t.fCee;
148 fCty=t.fCty; fCtz=t.fCtz; fCte=t.fCte; fCtt=t.fCtt;
149 fCcy=t.fCcy; fCcz=t.fCcz; fCce=t.fCce; fCct=t.fCct; fCcc=t.fCcc;
151 Int_t n=t.GetNumberOfClusters();
152 SetNumberOfClusters(n);
153 for (Int_t i=0; i<n; i++) {
154 fIndex[i]=t.fIndex[i];
158 // initialisation (i starts from n) [SR, GSI, 18.02.2003]
159 for(Int_t i=n; i<kMAX_CLUSTERS_PER_TRACK; i++) {
165 //_____________________________________________________________________________
166 AliTRDtrack::AliTRDtrack(const AliKalmanTrack& t, Double_t alpha)
169 // Constructor from AliTPCtrack or AliITStrack .
172 SetLabel(t.GetLabel());
174 SetMass(t.GetMass());
175 SetNumberOfClusters(0);
184 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
185 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
187 Double_t x, p[5]; t.GetExternalParameters(x,p);
199 //Conversion of the covariance matrix
200 Double_t c[15]; t.GetExternalCovariance(c);
202 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
204 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
205 Double_t c32=fX*c[13] - c[8];
206 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
209 fCzy=c[1 ]; fCzz=c[2 ];
210 fCey=c20; fCez=c21; fCee=c22;
211 fCty=c[6 ]; fCtz=c[7 ]; fCte=c32; fCtt=c[9 ];
212 fCcy=c[10]; fCcz=c[11]; fCce=c42; fCct=c[13]; fCcc=c[14];
214 // Initialization [SR, GSI, 18.02.2003]
215 for(Int_t i=0; i<kMAX_CLUSTERS_PER_TRACK; i++) {
220 //_____________________________________________________________________________
222 void AliTRDtrack::GetBarrelTrack(AliBarrelTrack *track) {
228 Double_t xr, vec[5], cov[15];
230 track->SetLabel(GetLabel());
231 track->SetX(fX, fAlpha);
232 track->SetNClusters(GetNumberOfClusters(), GetChi2());
233 track->SetNWrongClusters(fNWrong);
234 track->SetNRotate(fNRotate);
235 track->SetTime(fIntegratedTime, fIntegratedLength);
237 track->SetMass(fMass);
238 track->SetdEdX(fdEdx);
240 GetExternalParameters(xr, vec);
241 track->SetStateVector(vec);
243 GetExternalCovariance(cov);
244 track->SetCovarianceMatrix(cov);
246 //____________________________________________________________________________
247 void AliTRDtrack::GetExternalParameters(Double_t& xr, Double_t x[5]) const {
249 // This function returns external TRD track representation
259 //_____________________________________________________________________________
260 void AliTRDtrack::GetExternalCovariance(Double_t cc[15]) const {
262 // This function returns external representation of the covriance matrix.
264 Double_t a=GetConvConst();
266 Double_t c22=fX*fX*fCcc-2*fX*fCce+fCee;
267 Double_t c32=fX*fCct-fCte;
268 Double_t c20=fX*fCcy-fCey, c21=fX*fCcz-fCez, c42=fX*fCcc-fCce;
271 cc[1 ]=fCzy; cc[2 ]=fCzz;
272 cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22;
273 cc[6 ]=fCty; cc[7 ]=fCtz; cc[8 ]=c32; cc[9 ]=fCtt;
274 cc[10]=fCcy*a; cc[11]=fCcz*a; cc[12]=c42*a; cc[13]=fCct*a; cc[14]=fCcc*a*a;
279 //_____________________________________________________________________________
280 void AliTRDtrack::GetCovariance(Double_t cc[15]) const {
283 cc[1]=fCzy; cc[2]=fCzz;
284 cc[3]=fCey; cc[4]=fCez; cc[5]=fCee;
285 cc[6]=fCcy; cc[7]=fCcz; cc[8]=fCce; cc[9]=fCcc;
286 cc[10]=fCty; cc[11]=fCtz; cc[12]=fCte; cc[13]=fCct; cc[14]=fCtt;
290 //_____________________________________________________________________________
291 Int_t AliTRDtrack::Compare(const TObject *o) const {
293 // Compares tracks according to their Y2 or curvature
295 AliTRDtrack *t=(AliTRDtrack*)o;
296 // Double_t co=t->GetSigmaY2();
297 // Double_t c =GetSigmaY2();
299 Double_t co=TMath::Abs(t->GetC());
300 Double_t c =TMath::Abs(GetC());
303 else if (c<co) return -1;
307 //_____________________________________________________________________________
308 void AliTRDtrack::CookdEdx(Double_t low, Double_t up) {
309 //-----------------------------------------------------------------
310 // Calculates dE/dX within the "low" and "up" cuts.
311 //-----------------------------------------------------------------
314 Int_t nc=GetNumberOfClusters();
316 Float_t sorted[kMAX_CLUSTERS_PER_TRACK];
317 for (i=0; i < nc; i++) {
325 for (i=0; i<nc-1; i++) {
326 if (sorted[i]<=sorted[i+1]) continue;
327 Float_t tmp=sorted[i];
328 sorted[i]=sorted[i+1]; sorted[i+1]=tmp;
333 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc);
335 for (i=nl; i<=nu; i++) dedx += sorted[i];
342 //_____________________________________________________________________________
343 Int_t AliTRDtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho)
345 // Propagates a track of particle with mass=pm to a reference plane
346 // defined by x=xk through media of density=rho and radiationLength=x0
348 if (xk == fX) return 1;
350 if (TMath::Abs(fC*xk - fE) >= 0.99999) {
351 Int_t n=GetNumberOfClusters();
352 if (n>4) cerr << n << " AliTRDtrack: Propagation failed, \tPt = "
353 << GetPt() << "\t" << GetLabel() << "\t" << GetMass() << endl;
357 // track Length measurement [SR, GSI, 17.02.2003]
358 Double_t oldX = fX, oldY = fY, oldZ = fZ;
360 Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fY, z1=fZ;
361 Double_t c1=fC*x1 - fE;
362 if((c1*c1) > 1) return 0;
363 Double_t r1=sqrt(1.- c1*c1);
364 Double_t c2=fC*x2 - fE;
365 if((c2*c2) > 1) return 0;
366 Double_t r2=sqrt(1.- c2*c2);
368 fY += dx*(c1+c2)/(r1+r2);
369 fZ += dx*(c1+c2)/(c1*r2 + c2*r1)*fT;
372 Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
373 Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
374 Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
375 Double_t cr=c1*r2+c2*r1;
376 Double_t f12=-dx*fT*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
377 Double_t f13= dx*cc/cr;
378 Double_t f14=dx*fT*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);
381 Double_t b00=f02*fCey + f04*fCcy, b01=f12*fCey + f14*fCcy + f13*fCty;
382 Double_t b10=f02*fCez + f04*fCcz, b11=f12*fCez + f14*fCcz + f13*fCtz;
383 Double_t b20=f02*fCee + f04*fCce, b21=f12*fCee + f14*fCce + f13*fCte;
384 Double_t b30=f02*fCte + f04*fCct, b31=f12*fCte + f14*fCct + f13*fCtt;
385 Double_t b40=f02*fCce + f04*fCcc, b41=f12*fCce + f14*fCcc + f13*fCct;
388 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31;
390 //F*C*Ft = C + (a + b + bt)
392 fCzy += a01 + b01 + b10;
403 //Multiple scattering ******************
404 Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fY)*(y1-fY)+(z1-fZ)*(z1-fZ));
405 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
406 Double_t beta2=p2/(p2 + GetMass()*GetMass());
407 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
409 Double_t ey=fC*fX - fE, ez=fT;
410 Double_t xz=fC*ez, zz1=ez*ez+1, xy=fE+ey;
412 fCee += (2*ey*ez*ez*fE+1-ey*ey+ez*ez+fE*fE*ez*ez)*theta2;
413 fCte += ez*zz1*xy*theta2;
414 fCtt += zz1*zz1*theta2;
415 fCce += xz*ez*xy*theta2;
416 fCct += xz*zz1*theta2;
417 fCcc += xz*xz*theta2;
419 //Energy losses************************
420 if((5940*beta2/(1-beta2+1e-10) - beta2) < 0) return 0;
422 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2+1e-10)) - beta2)*d*rho;
425 fC*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
428 // track time measurement [SR, GSI 17.02.2002]
429 if (IsStartedTimeIntegral()) {
430 Double_t l2 = (fX-oldX)*(fX-oldX) + (fY-oldY)*(fY-oldY) + (fZ-oldZ)*(fZ-oldZ);
431 AddTimeStep(TMath::Sqrt(l2));
438 //_____________________________________________________________________________
439 Int_t AliTRDtrack::Update(const AliTRDcluster *c, Double_t chisq, UInt_t index, Double_t h01)
441 // Assignes found cluster to the track and updates track information
443 Bool_t fNoTilt = kTRUE;
444 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
446 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
447 r00+=fCyy; r01+=fCzy; r11+=fCzz;
448 Double_t det=r00*r11 - r01*r01;
449 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
451 Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
452 Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
453 Double_t k20=fCey*r00+fCez*r01, k21=fCey*r01+fCez*r11;
454 Double_t k30=fCty*r00+fCtz*r01, k31=fCty*r01+fCtz*r11;
455 Double_t k40=fCcy*r00+fCcz*r01, k41=fCcy*r01+fCcz*r11;
457 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
458 Double_t cur=fC + k40*dy + k41*dz, eta=fE + k20*dy + k21*dz;
460 Double_t c01=fCzy, c02=fCey, c03=fCty, c04=fCcy;
461 Double_t c12=fCez, c13=fCtz, c14=fCcz;
464 if (TMath::Abs(cur*fX-eta) >= 0.99999) {
465 Int_t n=GetNumberOfClusters();
466 if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
469 fY += k00*dy + k01*dz;
470 fZ += k10*dy + k11*dz;
472 //fT += k30*dy + k31*dz;
476 Double_t xu_factor = 100.; // empirical factor set by C.Xu
477 // in the first tilt version
478 r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2()*xu_factor;
479 r00+=(fCyy+2.0*h01*fCzy+h01*h01*fCzz);
480 r01+=(fCzy+h01*fCzz);
481 det=r00*r11 - r01*r01;
482 tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
484 k00=fCyy*r00+fCzy*(r01+h01*r00),k01=fCyy*r01+fCzy*(r11+h01*r01);
485 k10=fCzy*r00+fCzz*(r01+h01*r00),k11=fCzy*r01+fCzz*(r11+h01*r01);
486 k20=fCey*r00+fCez*(r01+h01*r00),k21=fCey*r01+fCez*(r11+h01*r01);
487 k30=fCty*r00+fCtz*(r01+h01*r00),k31=fCty*r01+fCtz*(r11+h01*r01);
488 k40=fCcy*r00+fCcz*(r01+h01*r00),k41=fCcy*r01+fCcz*(r11+h01*r01);
490 dy=c->GetY() - fY; dz=c->GetZ() - fZ;
493 cur=fC + k40*dy + k41*dz; eta=fE + k20*dy + k21*dz;
494 if (TMath::Abs(cur*fX-eta) >= 0.99999) {
495 Int_t n=GetNumberOfClusters();
496 if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
499 fY += k00*dy + k01*dz;
500 fZ += k10*dy + k11*dz;
502 //fT += k30*dy + k31*dz;
512 fCyy-=k00*fCyy+k01*fCzy; fCzy-=k00*c01+k01*fCzz;
513 fCey-=k00*c02+k01*c12; fCty-=k00*c03+k01*c13;
514 fCcy-=k00*c04+k01*c14;
516 fCzz-=k10*c01+k11*fCzz;
517 fCez-=k10*c02+k11*c12; fCtz-=k10*c03+k11*c13;
518 fCcz-=k10*c04+k11*c14;
520 fCee-=k20*c02+k21*c12; fCte-=k20*c03+k21*c13;
521 fCce-=k20*c04+k21*c14;
523 fCtt-=k30*c03+k31*c13;
524 fCct-=k40*c03+k41*c13;
526 fCcc-=k40*c04+k41*c14;
528 Int_t n=GetNumberOfClusters();
530 SetNumberOfClusters(n+1);
532 SetChi2(GetChi2()+chisq);
533 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
539 //_____________________________________________________________________________
540 Int_t AliTRDtrack::Rotate(Double_t alpha)
542 // Rotates track parameters in R*phi plane
547 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
548 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
550 Double_t x1=fX, y1=fY;
551 Double_t ca=cos(alpha), sa=sin(alpha);
552 Double_t r1=fC*fX - fE;
556 if((r1*r1) > 1) return 0;
557 fE=fE*ca + (fC*y1 + sqrt(1.- r1*r1))*sa;
559 Double_t r2=fC*fX - fE;
560 if (TMath::Abs(r2) >= 0.99999) {
561 Int_t n=GetNumberOfClusters();
562 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !\n";
566 if((r2*r2) > 1) return 0;
567 Double_t y0=fY + sqrt(1.- r2*r2)/fC;
568 if ((fY-y0)*fC >= 0.) {
569 Int_t n=GetNumberOfClusters();
570 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !!!\n";
575 Double_t f00=ca-1, f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa,
576 f20=fC*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1;
579 Double_t b00=fCyy*f00, b02=fCyy*f20+fCcy*f24+fCey*f22;
580 Double_t b10=fCzy*f00, b12=fCzy*f20+fCcz*f24+fCez*f22;
581 Double_t b20=fCey*f00, b22=fCey*f20+fCce*f24+fCee*f22;
582 Double_t b30=fCty*f00, b32=fCty*f20+fCct*f24+fCte*f22;
583 Double_t b40=fCcy*f00, b42=fCcy*f20+fCcc*f24+fCce*f22;
586 Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22;
588 //F*C*Ft = C + (a + b + bt)
603 //_____________________________________________________________________________
604 Double_t AliTRDtrack::GetPredictedChi2(const AliTRDcluster *c, Double_t h01) const
607 Bool_t fNoTilt = kTRUE;
608 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
609 Double_t chi2, dy, r00, r01, r11;
617 r00=c->GetSigmaY2(); r01=0.; r11=c->GetSigmaZ2();
618 r00+=fCyy; r01+=fCzy; r11+=fCzz;
620 Double_t det=r00*r11 - r01*r01;
621 if (TMath::Abs(det) < 1.e-10) {
622 Int_t n=GetNumberOfClusters();
623 if (n>4) cerr<<n<<" AliTRDtrack warning: Singular matrix !\n";
626 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
627 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
630 chi2 = (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
636 //_________________________________________________________________________
637 void AliTRDtrack::GetPxPyPz(Double_t& px, Double_t& py, Double_t& pz) const
639 // Returns reconstructed track momentum in the global system.
641 Double_t pt=TMath::Abs(GetPt()); // GeV/c
645 if(r > 1) { py = pt; px = 0; }
646 else if(r < -1) { py = -pt; px = 0; }
648 y0=fY + sqrt(1.- r*r)/fC;
649 px=-pt*(fY-y0)*fC; //cos(phi);
650 py=-pt*(fE-fX*fC); //sin(phi);
653 Double_t tmp=px*TMath::Cos(fAlpha) - py*TMath::Sin(fAlpha);
654 py=px*TMath::Sin(fAlpha) + py*TMath::Cos(fAlpha);
659 //_________________________________________________________________________
660 void AliTRDtrack::GetGlobalXYZ(Double_t& x, Double_t& y, Double_t& z) const
662 // Returns reconstructed track coordinates in the global system.
664 x = fX; y = fY; z = fZ;
665 Double_t tmp=x*TMath::Cos(fAlpha) - y*TMath::Sin(fAlpha);
666 y=x*TMath::Sin(fAlpha) + y*TMath::Cos(fAlpha);
671 //_________________________________________________________________________
672 void AliTRDtrack::ResetCovariance() {
674 // Resets covariance matrix
679 fCey=0.; fCez=0.; fCee*=10.;
680 fCty=0.; fCtz=0.; fCte=0.; fCtt*=10.;
681 fCcy=0.; fCcz=0.; fCce=0.; fCct=0.; fCcc*=10.;