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 1.16 2003/02/10 14:06:10 cblume
19 Add tracking without tilted pads as option
21 Revision 1.15 2003/01/27 16:34:49 cblume
22 Update of tracking by Sergei and Chuncheng
24 Revision 1.14 2002/11/07 15:52:09 cblume
25 Update of tracking code for tilted pads
27 Revision 1.13 2002/10/22 15:53:08 alibrary
28 Introducing Riostream.h
30 Revision 1.12 2002/10/14 14:57:44 hristov
31 Merging the VirtualMC branch to the main development branch (HEAD)
33 Revision 1.8.10.2 2002/07/24 10:09:31 alibrary
36 RRevision 1.11 2002/06/13 12:09:58 hristov
39 Revision 1.10 2002/06/12 09:54:35 cblume
40 Update of tracking code provided by Sergei
42 Revision 1.8 2001/05/30 12:17:47 hristov
43 Loop variables declared once
45 Revision 1.7 2001/05/28 17:07:58 hristov
46 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)
48 Revision 1.4 2000/12/08 16:07:02 cblume
49 Update of the tracking by Sergei
51 Revision 1.3 2000/10/15 23:40:01 cblume
54 Revision 1.2 2000/10/06 16:49:46 cblume
57 Revision 1.1.2.1 2000/09/22 14:47:52 cblume
62 #include <Riostream.h>
65 #include "AliTRDgeometry.h"
66 #include "AliTRDcluster.h"
67 #include "AliTRDtrack.h"
68 #include "../TPC/AliTPCtrack.h"
74 //_____________________________________________________________________________
76 AliTRDtrack::AliTRDtrack(const AliTRDcluster *c, UInt_t index,
77 const Double_t xx[5], const Double_t cc[15],
78 Double_t xref, Double_t alpha) : AliKalmanTrack() {
79 //-----------------------------------------------------------------
80 // This is the main track constructor.
81 //-----------------------------------------------------------------
86 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
87 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
91 fY=xx[0]; fZ=xx[1]; fE=xx[2]; fT=xx[3]; fC=xx[4];
94 fCzy=cc[1]; fCzz=cc[2];
95 fCey=cc[3]; fCez=cc[4]; fCee=cc[5];
96 fCty=cc[6]; fCtz=cc[7]; fCte=cc[8]; fCtt=cc[9];
97 fCcy=cc[10]; fCcz=cc[11]; fCce=cc[12]; fCct=cc[13]; fCcc=cc[14];
100 SetNumberOfClusters(1);
106 Double_t q = TMath::Abs(c->GetQ());
107 Double_t s = fX*fC - fE, t=fT;
108 if(s*s < 1) q *= TMath::Sqrt((1-s*s)/(1+t*t));
112 // initialisation [SR, GSI 18.02.2003] (i startd for 1)
113 for(Int_t i=1; i<kMAX_CLUSTERS_PER_TRACK; i++) {
119 //_____________________________________________________________________________
120 AliTRDtrack::AliTRDtrack(const AliTRDtrack& t) : AliKalmanTrack(t) {
125 SetLabel(t.GetLabel());
126 fSeedLab=t.GetSeedLabel();
128 SetChi2(t.GetChi2());
136 fY=t.fY; fZ=t.fZ; fE=t.fE; fT=t.fT; fC=t.fC;
139 fCzy=t.fCzy; fCzz=t.fCzz;
140 fCey=t.fCey; fCez=t.fCez; fCee=t.fCee;
141 fCty=t.fCty; fCtz=t.fCtz; fCte=t.fCte; fCtt=t.fCtt;
142 fCcy=t.fCcy; fCcz=t.fCcz; fCce=t.fCce; fCct=t.fCct; fCcc=t.fCcc;
144 Int_t n=t.GetNumberOfClusters();
145 SetNumberOfClusters(n);
146 for (Int_t i=0; i<n; i++) {
147 fIndex[i]=t.fIndex[i];
151 // initialisation (i starts from n) [SR, GSI, 18.02.2003]
152 for(Int_t i=n; i<kMAX_CLUSTERS_PER_TRACK; i++) {
158 //_____________________________________________________________________________
159 AliTRDtrack::AliTRDtrack(const AliKalmanTrack& t, Double_t alpha)
162 // Constructor from AliTPCtrack or AliITStrack .
165 SetLabel(t.GetLabel());
167 SetMass(t.GetMass());
168 SetNumberOfClusters(0);
175 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
176 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
178 Double_t x, p[5]; t.GetExternalParameters(x,p);
190 //Conversion of the covariance matrix
191 Double_t c[15]; t.GetExternalCovariance(c);
193 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
195 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
196 Double_t c32=fX*c[13] - c[8];
197 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
200 fCzy=c[1 ]; fCzz=c[2 ];
201 fCey=c20; fCez=c21; fCee=c22;
202 fCty=c[6 ]; fCtz=c[7 ]; fCte=c32; fCtt=c[9 ];
203 fCcy=c[10]; fCcz=c[11]; fCce=c42; fCct=c[13]; fCcc=c[14];
205 // Initialization [SR, GSI, 18.02.2003]
206 for(Int_t i=0; i<kMAX_CLUSTERS_PER_TRACK; i++) {
212 //____________________________________________________________________________
213 void AliTRDtrack::GetExternalParameters(Double_t& xr, Double_t x[5]) const {
215 // This function returns external TRD track representation
225 //_____________________________________________________________________________
226 void AliTRDtrack::GetExternalCovariance(Double_t cc[15]) const {
228 // This function returns external representation of the covriance matrix.
230 Double_t a=GetConvConst();
232 Double_t c22=fX*fX*fCcc-2*fX*fCce+fCee;
233 Double_t c32=fX*fCct-fCte;
234 Double_t c20=fX*fCcy-fCey, c21=fX*fCcz-fCez, c42=fX*fCcc-fCce;
237 cc[1 ]=fCzy; cc[2 ]=fCzz;
238 cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22;
239 cc[6 ]=fCty; cc[7 ]=fCtz; cc[8 ]=c32; cc[9 ]=fCtt;
240 cc[10]=fCcy*a; cc[11]=fCcz*a; cc[12]=c42*a; cc[13]=fCct*a; cc[14]=fCcc*a*a;
245 //_____________________________________________________________________________
246 void AliTRDtrack::GetCovariance(Double_t cc[15]) const {
249 cc[1]=fCzy; cc[2]=fCzz;
250 cc[3]=fCey; cc[4]=fCez; cc[5]=fCee;
251 cc[6]=fCcy; cc[7]=fCcz; cc[8]=fCce; cc[9]=fCcc;
252 cc[10]=fCty; cc[11]=fCtz; cc[12]=fCte; cc[13]=fCct; cc[14]=fCtt;
256 //_____________________________________________________________________________
257 Int_t AliTRDtrack::Compare(const TObject *o) const {
259 // Compares tracks according to their Y2 or curvature
261 AliTRDtrack *t=(AliTRDtrack*)o;
262 // Double_t co=t->GetSigmaY2();
263 // Double_t c =GetSigmaY2();
265 Double_t co=TMath::Abs(t->GetC());
266 Double_t c =TMath::Abs(GetC());
269 else if (c<co) return -1;
273 //_____________________________________________________________________________
274 void AliTRDtrack::CookdEdx(Double_t low, Double_t up) {
275 //-----------------------------------------------------------------
276 // Calculates dE/dX within the "low" and "up" cuts.
277 //-----------------------------------------------------------------
280 Int_t nc=GetNumberOfClusters();
282 Float_t sorted[kMAX_CLUSTERS_PER_TRACK];
283 for (i=0; i < nc; i++) {
291 for (i=0; i<nc-1; i++) {
292 if (sorted[i]<=sorted[i+1]) continue;
293 Float_t tmp=sorted[i];
294 sorted[i]=sorted[i+1]; sorted[i+1]=tmp;
299 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc);
301 for (i=nl; i<=nu; i++) dedx += sorted[i];
308 //_____________________________________________________________________________
309 Int_t AliTRDtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho)
311 // Propagates a track of particle with mass=pm to a reference plane
312 // defined by x=xk through media of density=rho and radiationLength=x0
314 if (TMath::Abs(fC*xk - fE) >= 0.99999) {
315 Int_t n=GetNumberOfClusters();
316 if (n>4) cerr<<n<<" AliTRDtrack warning: Propagation failed !\n";
320 // track Length measurement [SR, GSI, 17.02.2003]
321 Double_t oldX = fX, oldY = fY, oldZ = fZ;
323 Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fY, z1=fZ;
324 Double_t c1=fC*x1 - fE;
325 if((c1*c1) > 1) return 0;
326 Double_t r1=sqrt(1.- c1*c1);
327 Double_t c2=fC*x2 - fE;
328 if((c2*c2) > 1) return 0;
329 Double_t r2=sqrt(1.- c2*c2);
331 fY += dx*(c1+c2)/(r1+r2);
332 fZ += dx*(c1+c2)/(c1*r2 + c2*r1)*fT;
335 Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
336 Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
337 Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
338 Double_t cr=c1*r2+c2*r1;
339 Double_t f12=-dx*fT*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
340 Double_t f13= dx*cc/cr;
341 Double_t f14=dx*fT*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);
344 Double_t b00=f02*fCey + f04*fCcy, b01=f12*fCey + f14*fCcy + f13*fCty;
345 Double_t b10=f02*fCez + f04*fCcz, b11=f12*fCez + f14*fCcz + f13*fCtz;
346 Double_t b20=f02*fCee + f04*fCce, b21=f12*fCee + f14*fCce + f13*fCte;
347 Double_t b30=f02*fCte + f04*fCct, b31=f12*fCte + f14*fCct + f13*fCtt;
348 Double_t b40=f02*fCce + f04*fCcc, b41=f12*fCce + f14*fCcc + f13*fCct;
351 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31;
353 //F*C*Ft = C + (a + b + bt)
355 fCzy += a01 + b01 + b10;
366 //Multiple scattering ******************
367 Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fY)*(y1-fY)+(z1-fZ)*(z1-fZ));
368 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
369 Double_t beta2=p2/(p2 + GetMass()*GetMass());
370 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
372 Double_t ey=fC*fX - fE, ez=fT;
373 Double_t xz=fC*ez, zz1=ez*ez+1, xy=fE+ey;
375 fCee += (2*ey*ez*ez*fE+1-ey*ey+ez*ez+fE*fE*ez*ez)*theta2;
376 fCte += ez*zz1*xy*theta2;
377 fCtt += zz1*zz1*theta2;
378 fCce += xz*ez*xy*theta2;
379 fCct += xz*zz1*theta2;
380 fCcc += xz*xz*theta2;
382 //Energy losses************************
383 if((5940*beta2/(1-beta2+1e-10) - beta2) < 0) return 0;
385 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2+1e-10)) - beta2)*d*rho;
388 fC*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
391 // track time measurement [SR, GSI 17.02.2002]
392 if (IsStartedTimeIntegral()) {
393 Double_t l2 = (fX-oldX)*(fX-oldX) + (fY-oldY)*(fY-oldY) + (fZ-oldZ)*(fZ-oldZ);
394 AddTimeStep(TMath::Sqrt(l2));
401 //_____________________________________________________________________________
402 Int_t AliTRDtrack::Update(const AliTRDcluster *c, Double_t chisq, UInt_t index, Double_t h01)
404 // Assignes found cluster to the track and updates track information
406 Bool_t fNoTilt = kTRUE;
407 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
409 Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
410 r00+=fCyy; r01+=fCzy; r11+=fCzz;
411 Double_t det=r00*r11 - r01*r01;
412 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
414 Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
415 Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
416 Double_t k20=fCey*r00+fCez*r01, k21=fCey*r01+fCez*r11;
417 Double_t k30=fCty*r00+fCtz*r01, k31=fCty*r01+fCtz*r11;
418 Double_t k40=fCcy*r00+fCcz*r01, k41=fCcy*r01+fCcz*r11;
420 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
421 Double_t cur=fC + k40*dy + k41*dz, eta=fE + k20*dy + k21*dz;
423 Double_t c01=fCzy, c02=fCey, c03=fCty, c04=fCcy;
424 Double_t c12=fCez, c13=fCtz, c14=fCcz;
427 if (TMath::Abs(cur*fX-eta) >= 0.99999) {
428 Int_t n=GetNumberOfClusters();
429 if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
432 fY += k00*dy + k01*dz;
433 fZ += k10*dy + k11*dz;
435 fT += k30*dy + k31*dz;
439 Double_t xu_factor = 100.; // empirical factor set by C.Xu
440 // in the first tilt version
441 r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2()*xu_factor;
442 r00+=(fCyy+2.0*h01*fCzy+h01*h01*fCzz);
443 r01+=(fCzy+h01*fCzz);
444 det=r00*r11 - r01*r01;
445 tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
447 k00=fCyy*r00+fCzy*(r01+h01*r00),k01=fCyy*r01+fCzy*(r11+h01*r01);
448 k10=fCzy*r00+fCzz*(r01+h01*r00),k11=fCzy*r01+fCzz*(r11+h01*r01);
449 k20=fCey*r00+fCez*(r01+h01*r00),k21=fCey*r01+fCez*(r11+h01*r01);
450 k30=fCty*r00+fCtz*(r01+h01*r00),k31=fCty*r01+fCtz*(r11+h01*r01);
451 k40=fCcy*r00+fCcz*(r01+h01*r00),k41=fCcy*r01+fCcz*(r11+h01*r01);
453 dy=c->GetY() - fY; dz=c->GetZ() - fZ;
456 cur=fC + k40*dy + k41*dz; eta=fE + k20*dy + k21*dz;
457 if (TMath::Abs(cur*fX-eta) >= 0.99999) {
458 Int_t n=GetNumberOfClusters();
459 if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
462 fY += k00*dy + k01*dz;
463 fZ += k10*dy + k11*dz;
465 fT += k30*dy + k31*dz;
475 fCyy-=k00*fCyy+k01*fCzy; fCzy-=k00*c01+k01*fCzz;
476 fCey-=k00*c02+k01*c12; fCty-=k00*c03+k01*c13;
477 fCcy-=k00*c04+k01*c14;
479 fCzz-=k10*c01+k11*fCzz;
480 fCez-=k10*c02+k11*c12; fCtz-=k10*c03+k11*c13;
481 fCcz-=k10*c04+k11*c14;
483 fCee-=k20*c02+k21*c12; fCte-=k20*c03+k21*c13;
484 fCce-=k20*c04+k21*c14;
486 fCtt-=k30*c03+k31*c13;
487 fCct-=k40*c03+k41*c13;
489 fCcc-=k40*c04+k41*c14;
491 Int_t n=GetNumberOfClusters();
493 SetNumberOfClusters(n+1);
495 SetChi2(GetChi2()+chisq);
496 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
502 //_____________________________________________________________________________
503 Int_t AliTRDtrack::Rotate(Double_t alpha)
505 // Rotates track parameters in R*phi plane
508 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
509 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
511 Double_t x1=fX, y1=fY;
512 Double_t ca=cos(alpha), sa=sin(alpha);
513 Double_t r1=fC*fX - fE;
517 if((r1*r1) > 1) return 0;
518 fE=fE*ca + (fC*y1 + sqrt(1.- r1*r1))*sa;
520 Double_t r2=fC*fX - fE;
521 if (TMath::Abs(r2) >= 0.99999) {
522 Int_t n=GetNumberOfClusters();
523 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !\n";
527 if((r2*r2) > 1) return 0;
528 Double_t y0=fY + sqrt(1.- r2*r2)/fC;
529 if ((fY-y0)*fC >= 0.) {
530 Int_t n=GetNumberOfClusters();
531 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !!!\n";
536 Double_t f00=ca-1, f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa,
537 f20=fC*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1;
540 Double_t b00=fCyy*f00, b02=fCyy*f20+fCcy*f24+fCey*f22;
541 Double_t b10=fCzy*f00, b12=fCzy*f20+fCcz*f24+fCez*f22;
542 Double_t b20=fCey*f00, b22=fCey*f20+fCce*f24+fCee*f22;
543 Double_t b30=fCty*f00, b32=fCty*f20+fCct*f24+fCte*f22;
544 Double_t b40=fCcy*f00, b42=fCcy*f20+fCcc*f24+fCce*f22;
547 Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22;
549 //F*C*Ft = C + (a + b + bt)
564 //_____________________________________________________________________________
565 Double_t AliTRDtrack::GetPredictedChi2(const AliTRDcluster *c, Double_t h01) const
568 Bool_t fNoTilt = kTRUE;
569 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
570 Double_t chi2, dy, r00, r01, r11;
578 r00=c->GetSigmaY2(); r01=0.; r11=c->GetSigmaZ2();
579 r00+=fCyy; r01+=fCzy; r11+=fCzz;
581 Double_t det=r00*r11 - r01*r01;
582 if (TMath::Abs(det) < 1.e-10) {
583 Int_t n=GetNumberOfClusters();
584 if (n>4) cerr<<n<<" AliTRDtrack warning: Singular matrix !\n";
587 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
588 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
591 chi2 = (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
597 //_________________________________________________________________________
598 void AliTRDtrack::GetPxPyPz(Double_t& px, Double_t& py, Double_t& pz) const
600 // Returns reconstructed track momentum in the global system.
602 Double_t pt=TMath::Abs(GetPt()); // GeV/c
606 if(r > 1) { py = pt; px = 0; }
607 else if(r < -1) { py = -pt; px = 0; }
609 y0=fY + sqrt(1.- r*r)/fC;
610 px=-pt*(fY-y0)*fC; //cos(phi);
611 py=-pt*(fE-fX*fC); //sin(phi);
614 Double_t tmp=px*TMath::Cos(fAlpha) - py*TMath::Sin(fAlpha);
615 py=px*TMath::Sin(fAlpha) + py*TMath::Cos(fAlpha);
620 //_________________________________________________________________________
621 void AliTRDtrack::GetGlobalXYZ(Double_t& x, Double_t& y, Double_t& z) const
623 // Returns reconstructed track coordinates in the global system.
625 x = fX; y = fY; z = fZ;
626 Double_t tmp=x*TMath::Cos(fAlpha) - y*TMath::Sin(fAlpha);
627 y=x*TMath::Sin(fAlpha) + y*TMath::Cos(fAlpha);
632 //_________________________________________________________________________
633 void AliTRDtrack::ResetCovariance() {
635 // Resets covariance matrix
640 fCey=0.; fCez=0.; fCee*=10.;
641 fCty=0.; fCtz=0.; fCte=0.; fCtt*=10.;
642 fCcy=0.; fCcz=0.; fCce=0.; fCct=0.; fCcc*=10.;