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 #include <Riostream.h>
22 #include "AliESDtrack.h"
23 #include "AliTRDgeometry.h"
24 #include "AliTRDcluster.h"
25 #include "AliTRDtrack.h"
26 #include "AliTRDtracklet.h"
30 ///////////////////////////////////////////////////////////////////////////////
32 // Represents a reconstructed TRD track //
33 // Local TRD Kalman track //
35 ///////////////////////////////////////////////////////////////////////////////
37 AliTRDtrack::AliTRDtrack():
78 for (Int_t i=0; i<kNplane; i++) {
82 for (UInt_t i=0; i<kMAXCLUSTERSPERTRACK; i++) {
87 for (Int_t i=0; i<3; i++) fBudget[i] = 0;
89 //_____________________________________________________________________________
90 AliTRDtrack::AliTRDtrack(const AliTRDcluster *c, UInt_t index,
91 const Double_t xx[5], const Double_t cc[15],
92 Double_t xref, Double_t alpha) : AliKalmanTrack() {
93 //-----------------------------------------------------------------
94 // This is the main track constructor.
95 //-----------------------------------------------------------------
100 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
101 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
105 fY=xx[0]; fZ=xx[1]; fE=xx[2]; fT=xx[3]; fC=xx[4];
107 SaveLocalConvConst();
110 fCzy=cc[1]; fCzz=cc[2];
111 fCey=cc[3]; fCez=cc[4]; fCee=cc[5];
112 fCty=cc[6]; fCtz=cc[7]; fCte=cc[8]; fCtt=cc[9];
113 fCcy=cc[10]; fCcz=cc[11]; fCce=cc[12]; fCct=cc[13]; fCcc=cc[14];
116 SetNumberOfClusters(1);
121 for (Int_t i=0;i<kNplane;i++){
123 fTimBinPlane[i] = -1;
136 Double_t q = TMath::Abs(c->GetQ());
137 Double_t s = fX*fC - fE, t=fT;
138 if(s*s < 1) q *= TMath::Sqrt((1-s*s)/(1+t*t));
142 // initialisation [SR, GSI 18.02.2003] (i startd for 1)
143 for(UInt_t i=1; i<kMAXCLUSTERSPERTRACK; i++) {
146 fIndexBackup[i] = 0; //backup indexes MI
148 for (Int_t i=0;i<3;i++) { fBudget[i]=0;};
154 //_____________________________________________________________________________
155 AliTRDtrack::AliTRDtrack(const AliTRDtrack& t) : AliKalmanTrack(t)
161 SetLabel(t.GetLabel());
162 fSeedLab=t.GetSeedLabel();
164 SetChi2(t.GetChi2());
168 for (Int_t i=0;i<kNplane;i++){
169 fdEdxPlane[i] = t.fdEdxPlane[i];
170 fTimBinPlane[i] = t.fTimBinPlane[i];
171 fTracklets[i] = t.fTracklets[i];
176 fNRotate = t.fNRotate;
177 fStopped = t.fStopped;
179 fNExpected = t.fNExpected;
180 fNExpectedLast = t.fNExpectedLast;
183 fChi2Last = t.fChi2Last;
189 fY=t.fY; fZ=t.fZ; fE=t.fE; fT=t.fT; fC=t.fC;
192 fCzy=t.fCzy; fCzz=t.fCzz;
193 fCey=t.fCey; fCez=t.fCez; fCee=t.fCee;
194 fCty=t.fCty; fCtz=t.fCtz; fCte=t.fCte; fCtt=t.fCtt;
195 fCcy=t.fCcy; fCcz=t.fCcz; fCce=t.fCce; fCct=t.fCct; fCcc=t.fCcc;
197 Int_t n=t.GetNumberOfClusters();
198 SetNumberOfClusters(n);
199 for (Int_t i=0; i<n; i++) {
200 fIndex[i]=t.fIndex[i];
201 fIndexBackup[i]=t.fIndex[i]; // MI - backup indexes
205 // initialisation (i starts from n) [SR, GSI, 18.02.2003]
206 for(UInt_t i=n; i<kMAXCLUSTERSPERTRACK; i++) {
209 fIndexBackup[i] = 0; //MI backup indexes
211 for (Int_t i=0;i<6;i++){
212 fTracklets[i] = t.fTracklets[i];
214 for (Int_t i=0;i<3;i++) { fBudget[i]=t.fBudget[i];};
217 //_____________________________________________________________________________
218 AliTRDtrack::AliTRDtrack(const AliKalmanTrack& t, Double_t alpha)
222 // Constructor from AliTPCtrack or AliITStrack .
225 SetLabel(t.GetLabel());
227 SetMass(t.GetMass());
228 SetNumberOfClusters(0);
230 fdEdx=t.GetPIDsignal();
232 for (Int_t i=0;i<kNplane;i++){
234 fTimBinPlane[i] = -1;
250 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
251 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
253 Double_t x, p[5]; t.GetExternalParameters(x,p);
259 fT=p[3]; x=GetLocalConvConst();
263 //Conversion of the covariance matrix
264 Double_t c[15]; t.GetExternalCovariance(c);
266 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
268 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
269 Double_t c32=fX*c[13] - c[8];
270 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
273 fCzy=c[1 ]; fCzz=c[2 ];
274 fCey=c20; fCez=c21; fCee=c22;
275 fCty=c[6 ]; fCtz=c[7 ]; fCte=c32; fCtt=c[9 ];
276 fCcy=c[10]; fCcz=c[11]; fCce=c42; fCct=c[13]; fCcc=c[14];
278 // Initialization [SR, GSI, 18.02.2003]
279 for(UInt_t i=0; i<kMAXCLUSTERSPERTRACK; i++) {
282 fIndexBackup[i] = 0; // MI backup indexes
285 for (Int_t i=0;i<3;i++) { fBudget[i]=0;};
288 //_____________________________________________________________________________
289 AliTRDtrack::AliTRDtrack(const AliESDtrack& t)
293 // Constructor from AliESDtrack
296 SetLabel(t.GetLabel());
298 SetMass(t.GetMass());
299 SetNumberOfClusters(t.GetTRDclusters(fIndex));
300 Int_t ncl = t.GetTRDclusters(fIndexBackup);
301 for (UInt_t i=ncl;i<kMAXCLUSTERSPERTRACK;i++) {
303 fIndex[i] = 0; //MI store indexes
305 fdEdx=t.GetTRDsignal();
307 for (Int_t i=0;i<kNplane;i++){
308 fdEdxPlane[i] = t.GetTRDsignals(i);
309 fTimBinPlane[i] = t.GetTRDTimBin(i);
324 fAlpha = t.GetAlpha();
325 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
326 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
328 Double_t x, p[5]; t.GetExternalParameters(x,p);
329 //Conversion of the covariance matrix
330 Double_t c[15]; t.GetExternalCovariance(c);
331 if (t.GetStatus()&AliESDtrack::kTRDbackup){
332 t.GetOuterExternalParameters(fAlpha,x,p);
333 t.GetOuterExternalCovariance(c);
334 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
335 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
341 fZ=p[1]; SaveLocalConvConst();
342 fT=p[3]; x=GetLocalConvConst();
347 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
349 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
350 Double_t c32=fX*c[13] - c[8];
351 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
354 fCzy=c[1 ]; fCzz=c[2 ];
355 fCey=c20; fCez=c21; fCee=c22;
356 fCty=c[6 ]; fCtz=c[7 ]; fCte=c32; fCtt=c[9 ];
357 fCcy=c[10]; fCcz=c[11]; fCce=c42; fCct=c[13]; fCcc=c[14];
359 // Initialization [SR, GSI, 18.02.2003]
360 for(UInt_t i=0; i<kMAXCLUSTERSPERTRACK; i++) {
362 // fIndex[i] = 0; //MI store indexes
365 for (Int_t i=0;i<3;i++) { fBudget[i]=0;};
366 if ((t.GetStatus()&AliESDtrack::kTIME) == 0) return;
368 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
369 SetIntegratedLength(t.GetIntegratedLength());
373 //____________________________________________________________________________
374 AliTRDtrack::~AliTRDtrack()
380 if (fBackupTrack) delete fBackupTrack;
385 //____________________________________________________________________________
386 AliTRDtrack &AliTRDtrack::operator=(const AliTRDtrack &t)
389 // Assignment operator
404 fAlpha = t.GetAlpha();
405 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
406 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
412 // //____________________________________________________________________________
413 // AliTRDtrack * AliTRDtrack::MakeTrack(const AliTrackReference *ref, Double_t mass)
416 // // Make dummy track from the track reference
417 // // negative mass means opposite charge
421 // for (Int_t i=0;i<15;i++) cc[i]=0;
422 // Double_t x = ref->X(), y = ref->Y(), z = ref->Z();
423 // Double_t alpha = TMath::ATan2(y,x);
424 // Double_t xr = TMath::Sqrt(x*x+y*y);
427 // xx[3] = ref->Pz()/ref->Pt();
429 // Float_t xyz[3]={x,y,z};
430 // Float_t convConst = 0;
431 // (AliKalmanTrack::GetFieldMap())->Field(xyz,b);
432 // convConst=1000/0.299792458/(1e-13 - b[2]);
433 // xx[4] = 1./(convConst*ref->Pt());
434 // if (mass<0) xx[4]*=-1.; // negative mass - negative direction
435 // Double_t lcos = (x*ref->Px()+y*ref->Py())/(xr*ref->Pt());
436 // Double_t lsin = TMath::Sin(TMath::ACos(lcos));
437 // if (mass<0) lsin*=-1.;
438 // xx[2] = xr*xx[4]-lsin;
440 // AliTRDtrack * track = new AliTRDtrack(&cl,100,xx,cc,xr,alpha);
441 // track->SetMass(TMath::Abs(mass));
442 // track->StartTimeIntegral();
446 //____________________________________________________________________________
447 Float_t AliTRDtrack::StatusForTOF()
450 // Defines the status of the TOF extrapolation
453 Float_t res = (0.2 + 0.8*(fN/(fNExpected+5.)))*(0.4+0.6*fTracklets[5].GetN()/20.);
454 res *= (0.25+0.8*40./(40.+fBudget[2]));
458 if (GetNumberOfClusters()<20) return 0; //
459 if (fN>110&&fChi2/(Float_t(fN))<3) return 3; //gold
460 if (fNLast>30&&fChi2Last/(Float_t(fNLast))<3) return 3; //gold
461 if (fNLast>20&&fChi2Last/(Float_t(fNLast))<2) return 3; //gold
462 if (fNLast/(fNExpectedLast+3.)>0.8 && fChi2Last/Float_t(fNLast)<5&&fNLast>20) return 2; //silber
463 if (fNLast>5 &&((fNLast+1.)/(fNExpectedLast+1.))>0.8&&fChi2Last/(fNLast-5.)<6) return 1;
469 //____________________________________________________________________________
470 void AliTRDtrack::GetExternalParameters(Double_t& xr, Double_t x[5]) const
473 // This function returns external TRD track representation
485 //_____________________________________________________________________________
486 void AliTRDtrack::GetExternalCovariance(Double_t cc[15]) const
489 // This function returns external representation of the covriance matrix.
492 Double_t a=GetLocalConvConst();
494 Double_t c22=fX*fX*fCcc-2*fX*fCce+fCee;
495 Double_t c32=fX*fCct-fCte;
496 Double_t c20=fX*fCcy-fCey, c21=fX*fCcz-fCez, c42=fX*fCcc-fCce;
499 cc[1 ]=fCzy; cc[2 ]=fCzz;
500 cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22;
501 cc[6 ]=fCty; cc[7 ]=fCtz; cc[8 ]=c32; cc[9 ]=fCtt;
502 cc[10]=fCcy*a; cc[11]=fCcz*a; cc[12]=c42*a; cc[13]=fCct*a; cc[14]=fCcc*a*a;
506 //_____________________________________________________________________________
507 void AliTRDtrack::GetCovariance(Double_t cc[15]) const
510 // Returns the track covariance matrix
514 cc[1]=fCzy; cc[2]=fCzz;
515 cc[3]=fCey; cc[4]=fCez; cc[5]=fCee;
516 cc[6]=fCcy; cc[7]=fCcz; cc[8]=fCce; cc[9]=fCcc;
517 cc[10]=fCty; cc[11]=fCtz; cc[12]=fCte; cc[13]=fCct; cc[14]=fCtt;
521 //_____________________________________________________________________________
522 Int_t AliTRDtrack::Compare(const TObject *o) const
525 // Compares tracks according to their Y2 or curvature
528 AliTRDtrack *t=(AliTRDtrack*)o;
529 // Double_t co=t->GetSigmaY2();
530 // Double_t c =GetSigmaY2();
532 Double_t co=TMath::Abs(t->GetC());
533 Double_t c =TMath::Abs(GetC());
536 else if (c<co) return -1;
541 //_____________________________________________________________________________
542 void AliTRDtrack::CookdEdx(Double_t low, Double_t up) {
543 //-----------------------------------------------------------------
544 // Calculates dE/dX within the "low" and "up" cuts.
545 //-----------------------------------------------------------------
548 //Int_t nc=GetNumberOfClusters();
555 Float_t sorted[kMAXCLUSTERSPERTRACK];
556 for (i=0; i < nc; i++) {
559 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc);
561 //for (i=nl; i<=nu; i++) dedx += sorted[i];
563 for (i=0; i<nc; i++) dedx += sorted[i]; // ADDED by PS
564 if((nu-nl)) dedx /= (nu-nl); // ADDED by PS
568 // now real truncated mean
569 for (i=0; i < nc; i++) {
570 sorted[i]=TMath::Abs(fdQdl[i]);
572 Int_t * index = new Int_t[nc];
573 TMath::Sort(nc, sorted, index,kFALSE);
575 for (i=nl; i<=nu; i++) dedx += sorted[index[i]];
583 //_____________________________________________________________________________
584 Int_t AliTRDtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho)
586 // Propagates a track of particle with mass=pm to a reference plane
587 // defined by x=xk through media of density=rho and radiationLength=x0
589 if (xk == fX) return 1;
591 if (TMath::Abs(fC*xk - fE) >= 0.90000) {
592 // Int_t n=GetNumberOfClusters();
593 //if (n>4) cerr << n << " AliTRDtrack: Propagation failed, \tPt = "
594 // << GetPt() << "\t" << GetLabel() << "\t" << GetMass() << endl;
597 Double_t lcc=GetLocalConvConst();
599 // track Length measurement [SR, GSI, 17.02.2003]
600 Double_t oldX = fX, oldY = fY, oldZ = fZ;
602 Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fY, z1=fZ;
603 Double_t c1=fC*x1 - fE;
604 if((c1*c1) > 1) return 0;
605 Double_t r1=sqrt(1.- c1*c1);
606 Double_t c2=fC*x2 - fE;
607 if((c2*c2) > 1) return 0;
608 Double_t r2=sqrt(1.- c2*c2);
610 fY += dx*(c1+c2)/(r1+r2);
611 fZ += dx*(c1+c2)/(c1*r2 + c2*r1)*fT;
614 Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
615 Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
616 Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
617 Double_t cr=c1*r2+c2*r1;
618 Double_t f12=-dx*fT*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
619 Double_t f13= dx*cc/cr;
620 Double_t f14=dx*fT*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);
623 Double_t b00=f02*fCey + f04*fCcy, b01=f12*fCey + f14*fCcy + f13*fCty;
624 Double_t b10=f02*fCez + f04*fCcz, b11=f12*fCez + f14*fCcz + f13*fCtz;
625 Double_t b20=f02*fCee + f04*fCce, b21=f12*fCee + f14*fCce + f13*fCte;
626 Double_t b30=f02*fCte + f04*fCct, b31=f12*fCte + f14*fCct + f13*fCtt;
627 Double_t b40=f02*fCce + f04*fCcc, b41=f12*fCce + f14*fCcc + f13*fCct;
630 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31;
632 //F*C*Ft = C + (a + b + bt)
634 fCzy += a01 + b01 + b10;
645 //Change of the magnetic field *************
646 SaveLocalConvConst();
648 fC*=lcc/GetLocalConvConst();
651 //Multiple scattering ******************
652 Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fY)*(y1-fY)+(z1-fZ)*(z1-fZ));
653 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
654 Double_t beta2=p2/(p2 + GetMass()*GetMass());
655 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
657 Double_t ey=fC*fX - fE, ez=fT;
658 Double_t xz=fC*ez, zz1=ez*ez+1, xy=fE+ey;
660 fCee += (2*ey*ez*ez*fE+1-ey*ey+ez*ez+fE*fE*ez*ez)*theta2;
661 fCte += ez*zz1*xy*theta2;
662 fCtt += zz1*zz1*theta2;
663 fCce += xz*ez*xy*theta2;
664 fCct += xz*zz1*theta2;
665 fCcc += xz*xz*theta2;
667 Double_t dc22 = (1-ey*ey+xz*xz*fX*fX)*theta2;
668 Double_t dc32 = (xz*fX*zz1)*theta2;
669 Double_t dc33 = (zz1*zz1)*theta2;
670 Double_t dc42 = (xz*fX*xz)*theta2;
671 Double_t dc43 = (zz1*xz)*theta2;
672 Double_t dc44 = (xz*xz)*theta2;
680 //Energy losses************************
681 if((5940*beta2/(1-beta2+1e-10) - beta2) < 0) return 0;
683 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2+1e-10)) - beta2)*d*rho;
684 Float_t budget = d* rho;
687 // suspicious part - think about it ?
688 Double_t kinE = TMath::Sqrt(p2);
689 if (dE>0.8*kinE) dE = 0.8*kinE; //
690 if (dE<0) dE = 0.0; // not valid region for Bethe bloch
696 fC*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
698 // Double_t sigmade = 0.1*dE*TMath::Sqrt(TMath::Sqrt(1+fT*fT)*90./(d+0.0001)); // 20 percent fluctuation - normalized to some length
699 Double_t sigmade = 0.07*TMath::Sqrt(TMath::Abs(dE)); // energy loss fluctuation
700 Double_t sigmac2 = sigmade*sigmade*fC*fC*(p2+GetMass()*GetMass())/(p2*p2);
702 fCee += fX*fX*sigmac2;
704 // track time measurement [SR, GSI 17.02.2002]
706 if (IsStartedTimeIntegral()) {
707 Double_t l2 = TMath::Sqrt((fX-oldX)*(fX-oldX) + (fY-oldY)*(fY-oldY) + (fZ-oldZ)*(fZ-oldZ));
708 if (TMath::Abs(l2*fC)>0.0001){
709 // make correction for curvature if neccesary
710 l2 = 0.5*TMath::Sqrt((fX-oldX)*(fX-oldX) + (fY-oldY)*(fY-oldY));
711 l2 = 2*TMath::ASin(l2*fC)/fC;
712 l2 = TMath::Sqrt(l2*l2+(fZ-oldZ)*(fZ-oldZ));
720 //_____________________________________________________________________________
721 Int_t AliTRDtrack::Update(const AliTRDcluster *c, Double_t chisq, UInt_t index
724 // Assignes found cluster to the track and updates track information
726 Bool_t fNoTilt = kTRUE;
727 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
728 // add angular effect to the error contribution - MI
729 Float_t tangent2 = (fC*fX-fE)*(fC*fX-fE);
730 if (tangent2 < 0.90000){
731 tangent2 = tangent2/(1.-tangent2);
733 Float_t errang = tangent2*0.04; //
734 Float_t padlength = TMath::Sqrt(c->GetSigmaZ2()*12.);
736 Double_t r00=c->GetSigmaY2() +errang, r01=0., r11=c->GetSigmaZ2()*100.;
737 r00+=fCyy; r01+=fCzy; r11+=fCzz;
738 Double_t det=r00*r11 - r01*r01;
739 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
741 Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
742 Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
743 Double_t k20=fCey*r00+fCez*r01, k21=fCey*r01+fCez*r11;
744 Double_t k30=fCty*r00+fCtz*r01, k31=fCty*r01+fCtz*r11;
745 Double_t k40=fCcy*r00+fCcz*r01, k41=fCcy*r01+fCcz*r11;
747 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
748 Double_t cur=fC + k40*dy + k41*dz, eta=fE + k20*dy + k21*dz;
752 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
753 // Int_t n=GetNumberOfClusters();
754 //if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
757 fY += k00*dy + k01*dz;
758 fZ += k10*dy + k11*dz;
760 //fT += k30*dy + k31*dz;
764 Double_t xuFactor = 100.; // empirical factor set by C.Xu
765 // in the first tilt version
766 dy=c->GetY() - fY; dz=c->GetZ() - fZ;
769 if (TMath::Abs(dz)>padlength/2.){
770 Float_t dy2 = c->GetY() - fY;
771 Float_t sign = (dz>0) ? -1.: 1.;
772 dy2+=h01*sign*padlength/2.;
779 r00=c->GetSigmaY2()+errang+add, r01=0., r11=c->GetSigmaZ2()*xuFactor;
780 r00+=(fCyy+2.0*h01*fCzy+h01*h01*fCzz);
781 r01+=(fCzy+h01*fCzz);
784 det=r00*r11 - r01*r01;
785 tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
787 k00=fCyy*r00+fCzy*(r01+h01*r00),k01=fCyy*r01+fCzy*(r11+h01*r01);
788 k10=fCzy*r00+fCzz*(r01+h01*r00),k11=fCzy*r01+fCzz*(r11+h01*r01);
789 k20=fCey*r00+fCez*(r01+h01*r00),k21=fCey*r01+fCez*(r11+h01*r01);
790 k30=fCty*r00+fCtz*(r01+h01*r00),k31=fCty*r01+fCtz*(r11+h01*r01);
791 k40=fCcy*r00+fCcz*(r01+h01*r00),k41=fCcy*r01+fCcz*(r11+h01*r01);
794 cur=fC + k40*dy + k41*dz; eta=fE + k20*dy + k21*dz;
795 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
796 // Int_t n=GetNumberOfClusters();
797 //if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
800 fY += k00*dy + k01*dz;
801 fZ += k10*dy + k11*dz;
803 fT += k30*dy + k31*dz;
813 Double_t c01=fCzy, c02=fCey, c03=fCty, c04=fCcy;
814 Double_t c12=fCez, c13=fCtz, c14=fCcz;
817 fCyy-=k00*fCyy+k01*fCzy; fCzy-=k00*c01+k01*fCzz;
818 fCey-=k00*c02+k01*c12; fCty-=k00*c03+k01*c13;
819 fCcy-=k00*c04+k01*c14;
821 fCzz-=k10*c01+k11*fCzz;
822 fCez-=k10*c02+k11*c12; fCtz-=k10*c03+k11*c13;
823 fCcz-=k10*c04+k11*c14;
825 fCee-=k20*c02+k21*c12; fCte-=k20*c03+k21*c13;
826 fCce-=k20*c04+k21*c14;
828 fCtt-=k30*c03+k31*c13;
829 fCct-=k40*c03+k41*c13;
830 //fCct-=k30*c04+k31*c14; // symmetric formula MI
832 fCcc-=k40*c04+k41*c14;
834 Int_t n=GetNumberOfClusters();
836 SetNumberOfClusters(n+1);
838 SetChi2(GetChi2()+chisq);
839 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
845 //_____________________________________________________________________________
846 Int_t AliTRDtrack::UpdateMI(const AliTRDcluster *c, Double_t chisq, UInt_t index, Double_t h01,
849 // Assignes found cluster to the track and updates track information
851 Bool_t fNoTilt = kTRUE;
852 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
853 // add angular effect to the error contribution and make correction - MI
854 //AliTRDclusterCorrection *corrector = AliTRDclusterCorrection::GetCorrection();
856 Double_t tangent2 = (fC*fX-fE)*(fC*fX-fE);
857 if (tangent2 < 0.90000){
858 tangent2 = tangent2/(1.-tangent2);
860 Double_t tangent = TMath::Sqrt(tangent2);
861 if ((fC*fX-fE)<0) tangent*=-1;
862 // Double_t correction = 0*plane;
863 Double_t errang = tangent2*0.04; //
864 Double_t errsys =0.025*0.025*20; //systematic error part
866 if (c->GetNPads()==4) extend=2;
867 //if (c->GetNPads()==5) extend=3;
868 //if (c->GetNPads()==6) extend=3;
869 //if (c->GetQ()<15) return 1;
874 correction = corrector->GetCorrection(plane,c->GetLocalTimeBin(),tangent);
875 if (TMath::Abs(correction)>0){
877 errang = corrector->GetSigma(plane,c->GetLocalTimeBin(),tangent);
879 errang += tangent2*0.04;
884 // Double_t padlength = TMath::Sqrt(c->GetSigmaZ2()*12.);
886 Double_t r00=(c->GetSigmaY2() +errang+errsys)*extend, r01=0., r11=c->GetSigmaZ2()*10000.;
887 r00+=fCyy; r01+=fCzy; r11+=fCzz;
888 Double_t det=r00*r11 - r01*r01;
889 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
891 Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
892 Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
893 Double_t k20=fCey*r00+fCez*r01, k21=fCey*r01+fCez*r11;
894 Double_t k30=fCty*r00+fCtz*r01, k31=fCty*r01+fCtz*r11;
895 Double_t k40=fCcy*r00+fCcz*r01, k41=fCcy*r01+fCcz*r11;
897 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
898 Double_t cur=fC + k40*dy + k41*dz, eta=fE + k20*dy + k21*dz;
902 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
903 // Int_t n=GetNumberOfClusters();
904 //if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
907 fY += k00*dy + k01*dz;
908 fZ += k10*dy + k11*dz;
910 //fT += k30*dy + k31*dz;
914 Double_t padlength = TMath::Sqrt(c->GetSigmaZ2()*12);
916 Double_t xuFactor = 1000.; // empirical factor set by C.Xu
917 // in the first tilt version
918 dy=c->GetY() - fY; dz=c->GetZ() - fZ;
919 //dy=dy+h01*dz+correction;
921 Double_t tiltdz = dz;
922 if (TMath::Abs(tiltdz)>padlength/2.) {
923 tiltdz = TMath::Sign(padlength/2,dz);
929 if (TMath::Abs(dz)>padlength/2.){
930 //Double_t dy2 = c->GetY() - fY;
931 //Double_t sign = (dz>0) ? -1.: 1.;
932 //dy2-=h01*sign*padlength/2.;
936 Double_t s00 = (c->GetSigmaY2()+errang)*extend+errsys+add; // error pad
937 Double_t s11 = c->GetSigmaZ2()*xuFactor; // error pad-row
939 r00 = fCyy + 2*fCzy*h01 + fCzz*h01*h01+s00;
940 r01 = fCzy + fCzz*h01;
942 det = r00*r11 - r01*r01;
944 tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
947 k00=fCyy*r00+fCzy*(r01+h01*r00),k01=fCyy*r01+fCzy*(r11+h01*r01);
948 k10=fCzy*r00+fCzz*(r01+h01*r00),k11=fCzy*r01+fCzz*(r11+h01*r01);
949 k20=fCey*r00+fCez*(r01+h01*r00),k21=fCey*r01+fCez*(r11+h01*r01);
950 k30=fCty*r00+fCtz*(r01+h01*r00),k31=fCty*r01+fCtz*(r11+h01*r01);
951 k40=fCcy*r00+fCcz*(r01+h01*r00),k41=fCcy*r01+fCcz*(r11+h01*r01);
954 cur=fC + k40*dy + k41*dz; eta=fE + k20*dy + k21*dz;
955 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
956 //Int_t n=GetNumberOfClusters();
957 // if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
960 fY += k00*dy + k01*dz;
961 fZ += k10*dy + k11*dz;
963 fT += k30*dy + k31*dz;
976 Double_t oldyy = fCyy, oldzz = fCzz; //, oldee=fCee, oldcc =fCcc;
977 Double_t oldzy = fCzy, oldey = fCey, oldty=fCty, oldcy =fCcy;
978 Double_t oldez = fCez, oldtz = fCtz, oldcz=fCcz;
979 //Double_t oldte = fCte, oldce = fCce;
980 //Double_t oldct = fCct;
982 fCyy-=k00*oldyy+k01*oldzy;
983 fCzy-=k10*oldyy+k11*oldzy;
984 fCey-=k20*oldyy+k21*oldzy;
985 fCty-=k30*oldyy+k31*oldzy;
986 fCcy-=k40*oldyy+k41*oldzy;
988 fCzz-=k10*oldzy+k11*oldzz;
989 fCez-=k20*oldzy+k21*oldzz;
990 fCtz-=k30*oldzy+k31*oldzz;
991 fCcz-=k40*oldzy+k41*oldzz;
993 fCee-=k20*oldey+k21*oldez;
994 fCte-=k30*oldey+k31*oldez;
995 fCce-=k40*oldey+k41*oldez;
997 fCtt-=k30*oldty+k31*oldtz;
998 fCct-=k40*oldty+k41*oldtz;
1000 fCcc-=k40*oldcy+k41*oldcz;
1003 Int_t n=GetNumberOfClusters();
1005 SetNumberOfClusters(n+1);
1007 SetChi2(GetChi2()+chisq);
1008 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
1014 //_____________________________________________________________________________
1015 Int_t AliTRDtrack::UpdateMI(const AliTRDtracklet &tracklet)
1018 // Assignes found tracklet to the track and updates track information
1021 Double_t r00=(tracklet.GetTrackletSigma2()), r01=0., r11= 10000.;
1022 r00+=fCyy; r01+=fCzy; r11+=fCzz;
1024 Double_t det=r00*r11 - r01*r01;
1025 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
1028 Double_t dy=tracklet.GetY() - fY, dz=tracklet.GetZ() - fZ;
1031 Double_t s00 = tracklet.GetTrackletSigma2(); // error pad
1032 Double_t s11 = 100000; // error pad-row
1033 Float_t h01 = tracklet.GetTilt();
1035 // r00 = fCyy + 2*fCzy*h01 + fCzz*h01*h01+s00;
1036 r00 = fCyy + fCzz*h01*h01+s00;
1037 // r01 = fCzy + fCzz*h01;
1040 det = r00*r11 - r01*r01;
1042 tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
1044 Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
1045 Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
1046 Double_t k20=fCey*r00+fCez*r01, k21=fCey*r01+fCez*r11;
1047 Double_t k30=fCty*r00+fCtz*r01, k31=fCty*r01+fCtz*r11;
1048 Double_t k40=fCcy*r00+fCcz*r01, k41=fCcy*r01+fCcz*r11;
1051 // k00=fCyy*r00+fCzy*(r01+h01*r00),k01=fCyy*r01+fCzy*(r11+h01*r01);
1052 // k10=fCzy*r00+fCzz*(r01+h01*r00),k11=fCzy*r01+fCzz*(r11+h01*r01);
1053 // k20=fCey*r00+fCez*(r01+h01*r00),k21=fCey*r01+fCez*(r11+h01*r01);
1054 // k30=fCty*r00+fCtz*(r01+h01*r00),k31=fCty*r01+fCtz*(r11+h01*r01);
1055 // k40=fCcy*r00+fCcz*(r01+h01*r00),k41=fCcy*r01+fCcz*(r11+h01*r01);
1057 //Update measurement
1058 Double_t cur=fC + k40*dy + k41*dz, eta=fE + k20*dy + k21*dz;
1059 // cur=fC + k40*dy + k41*dz; eta=fE + k20*dy + k21*dz;
1060 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
1061 //Int_t n=GetNumberOfClusters();
1062 // if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
1072 fY += k00*dy + k01*dz;
1073 fZ += k10*dy + k11*dz;
1075 fT += k30*dy + k31*dz;
1082 Double_t oldyy = fCyy, oldzz = fCzz; //, oldee=fCee, oldcc =fCcc;
1083 Double_t oldzy = fCzy, oldey = fCey, oldty=fCty, oldcy =fCcy;
1084 Double_t oldez = fCez, oldtz = fCtz, oldcz=fCcz;
1085 //Double_t oldte = fCte, oldce = fCce;
1086 //Double_t oldct = fCct;
1088 fCyy-=k00*oldyy+k01*oldzy;
1089 fCzy-=k10*oldyy+k11*oldzy;
1090 fCey-=k20*oldyy+k21*oldzy;
1091 fCty-=k30*oldyy+k31*oldzy;
1092 fCcy-=k40*oldyy+k41*oldzy;
1094 fCzz-=k10*oldzy+k11*oldzz;
1095 fCez-=k20*oldzy+k21*oldzz;
1096 fCtz-=k30*oldzy+k31*oldzz;
1097 fCcz-=k40*oldzy+k41*oldzz;
1099 fCee-=k20*oldey+k21*oldez;
1100 fCte-=k30*oldey+k31*oldez;
1101 fCce-=k40*oldey+k41*oldez;
1103 fCtt-=k30*oldty+k31*oldtz;
1104 fCct-=k40*oldty+k41*oldtz;
1106 fCcc-=k40*oldcy+k41*oldcz;
1109 Int_t n=GetNumberOfClusters();
1111 SetNumberOfClusters(n+1);
1113 SetChi2(GetChi2()+chisq);
1114 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
1121 //_____________________________________________________________________________
1122 Int_t AliTRDtrack::Rotate(Double_t alpha, Bool_t absolute)
1124 // Rotates track parameters in R*phi plane
1125 // if absolute rotation alpha is in global system
1126 // otherwise alpha rotation is relative to the current rotation angle
1136 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
1137 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
1139 Double_t x1=fX, y1=fY;
1140 Double_t ca=cos(alpha), sa=sin(alpha);
1141 Double_t r1=fC*fX - fE;
1145 if((r1*r1) > 1) return 0;
1146 fE=fE*ca + (fC*y1 + sqrt(1.- r1*r1))*sa;
1148 Double_t r2=fC*fX - fE;
1149 if (TMath::Abs(r2) >= 0.90000) {
1150 Int_t n=GetNumberOfClusters();
1151 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !\n";
1155 if((r2*r2) > 1) return 0;
1156 Double_t y0=fY + sqrt(1.- r2*r2)/fC;
1157 if ((fY-y0)*fC >= 0.) {
1158 Int_t n=GetNumberOfClusters();
1159 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !!!\n";
1164 Double_t f00=ca-1, f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa,
1165 f20=fC*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1;
1168 Double_t b00=fCyy*f00, b02=fCyy*f20+fCcy*f24+fCey*f22;
1169 Double_t b10=fCzy*f00, b12=fCzy*f20+fCcz*f24+fCez*f22;
1170 Double_t b20=fCey*f00, b22=fCey*f20+fCce*f24+fCee*f22;
1171 Double_t b30=fCty*f00, b32=fCty*f20+fCct*f24+fCte*f22;
1172 Double_t b40=fCcy*f00, b42=fCcy*f20+fCcc*f24+fCce*f22;
1175 Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22;
1177 //F*C*Ft = C + (a + b + bt)
1178 fCyy += a00 + 2*b00;
1180 fCey += a02+b20+b02;
1185 fCee += a22 + 2*b22;
1192 //_____________________________________________________________________________
1193 Double_t AliTRDtrack::GetPredictedChi2(const AliTRDcluster *c, Double_t h01) const
1196 // Returns the track chi2
1199 Bool_t fNoTilt = kTRUE;
1200 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
1201 Double_t chi2, dy, r00, r01, r11;
1205 r00=c->GetSigmaY2();
1209 Double_t padlength = TMath::Sqrt(c->GetSigmaZ2()*12);
1211 r00=c->GetSigmaY2(); r01=0.; r11=c->GetSigmaZ2();
1212 r00+=fCyy; r01+=fCzy; r11+=fCzz;
1214 Double_t det=r00*r11 - r01*r01;
1215 if (TMath::Abs(det) < 1.e-10) {
1216 Int_t n=GetNumberOfClusters();
1217 if (n>4) cerr<<n<<" AliTRDtrack warning: Singular matrix !\n";
1220 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
1221 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
1222 Double_t tiltdz = dz;
1223 if (TMath::Abs(tiltdz)>padlength/2.) {
1224 tiltdz = TMath::Sign(padlength/2,dz);
1229 chi2 = (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
1236 //_________________________________________________________________________
1237 void AliTRDtrack::GetPxPyPz(Double_t& px, Double_t& py, Double_t& pz) const
1239 // Returns reconstructed track momentum in the global system.
1241 Double_t pt=TMath::Abs(GetPt()); // GeV/c
1242 Double_t r=fC*fX-fE;
1245 if(r > 1) { py = pt; px = 0; }
1246 else if(r < -1) { py = -pt; px = 0; }
1248 y0=fY + sqrt(1.- r*r)/fC;
1249 px=-pt*(fY-y0)*fC; //cos(phi);
1250 py=-pt*(fE-fX*fC); //sin(phi);
1253 Double_t tmp=px*TMath::Cos(fAlpha) - py*TMath::Sin(fAlpha);
1254 py=px*TMath::Sin(fAlpha) + py*TMath::Cos(fAlpha);
1259 //_________________________________________________________________________
1260 void AliTRDtrack::GetGlobalXYZ(Double_t& x, Double_t& y, Double_t& z) const
1262 // Returns reconstructed track coordinates in the global system.
1264 x = fX; y = fY; z = fZ;
1265 Double_t tmp=x*TMath::Cos(fAlpha) - y*TMath::Sin(fAlpha);
1266 y=x*TMath::Sin(fAlpha) + y*TMath::Cos(fAlpha);
1271 //_________________________________________________________________________
1272 void AliTRDtrack::ResetCovariance()
1275 // Resets covariance matrix
1280 fCey=0.; fCez=0.; fCee*=10.;
1281 fCty=0.; fCtz=0.; fCte=0.; fCtt*=10.;
1282 fCcy=0.; fCcz=0.; fCce=0.; fCct=0.; fCcc*=10.;
1286 //_____________________________________________________________________________
1287 void AliTRDtrack::ResetCovariance(Float_t mult)
1290 // Resets covariance matrix
1295 fCey*=0.; fCez*=0.; fCee*=mult;
1296 fCty*=0.; fCtz*=0.; fCte*=0.; fCtt*=1.;
1297 fCcy*=0.; fCcz*=0.; fCce*=0.; fCct*=0.; fCcc*=mult;
1301 //_____________________________________________________________________________
1302 void AliTRDtrack::MakeBackupTrack()
1305 // Creates a backup track
1308 if (fBackupTrack) delete fBackupTrack;
1309 fBackupTrack = new AliTRDtrack(*this);
1313 //_____________________________________________________________________________
1314 Int_t AliTRDtrack::GetProlongation(Double_t xk, Double_t &y, Double_t &z)
1317 // Find prolongation at given x
1318 // return 0 if not exist
1320 Double_t c1=fC*fX - fE;
1321 if (TMath::Abs(c1)>1.) return 0;
1322 Double_t r1=TMath::Sqrt(1.- c1*c1);
1323 Double_t c2=fC*xk - fE;
1324 if (TMath::Abs(c2)>1.) return 0;
1325 Double_t r2=TMath::Sqrt(1.- c2*c2);
1326 y =fY + (xk-fX)*(c1+c2)/(r1+r2);
1327 z =fZ + (xk-fX)*(c1+c2)/(c1*r2 + c2*r1)*fT;
1333 //_____________________________________________________________________________
1334 Int_t AliTRDtrack::PropagateToX(Double_t xr, Double_t step)
1337 // Propagate track to given x position
1338 // works inside of the 20 degree segmentation (local cooordinate frame for TRD , TPC, TOF)
1340 // material budget from geo manager
1342 Double_t xyz0[3], xyz1[3],y,z;
1343 const Double_t kAlphac = TMath::Pi()/9.;
1344 const Double_t kTalphac = TMath::Tan(kAlphac*0.5);
1345 // critical alpha - cross sector indication
1347 Double_t dir = (fX>xr) ? -1.:1.;
1349 for (Double_t x=fX+dir*step;dir*x<dir*xr;x+=dir*step){
1351 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1352 GetProlongation(x,y,z);
1353 xyz1[0] = x*TMath::Cos(fAlpha)+y*TMath::Sin(fAlpha);
1354 xyz1[1] = x*TMath::Sin(fAlpha)-y*TMath::Cos(fAlpha);
1357 AliKalmanTrack::MeanMaterialBudget(xyz0,xyz1,param);
1359 if (param[0]>0&¶m[1]>0) PropagateTo(x,param[1],param[0]);
1360 if (fY>fX*kTalphac){
1363 if (fY<-fX*kTalphac){
1374 //_____________________________________________________________________________
1375 Int_t AliTRDtrack::PropagateToR(Double_t r,Double_t step)
1378 // propagate track to the radial position
1379 // rotation always connected to the last track position
1381 Double_t xyz0[3], xyz1[3],y,z;
1382 Double_t radius = TMath::Sqrt(fX*fX+fY*fY);
1383 Double_t dir = (radius>r) ? -1.:1.; // direction +-
1385 for (Double_t x=radius+dir*step;dir*x<dir*r;x+=dir*step){
1386 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1387 Double_t alpha = TMath::ATan2(xyz0[1],xyz0[0]);
1388 Rotate(alpha,kTRUE);
1389 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1390 GetProlongation(x,y,z);
1391 xyz1[0] = x*TMath::Cos(alpha)+y*TMath::Sin(alpha);
1392 xyz1[1] = x*TMath::Sin(alpha)-y*TMath::Cos(alpha);
1395 AliKalmanTrack::MeanMaterialBudget(xyz0,xyz1,param);
1396 if (param[1]<=0) param[1] =100000000;
1397 PropagateTo(x,param[1],param[0]);
1399 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1400 Double_t alpha = TMath::ATan2(xyz0[1],xyz0[0]);
1401 Rotate(alpha,kTRUE);
1402 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1403 GetProlongation(r,y,z);
1404 xyz1[0] = r*TMath::Cos(alpha)+y*TMath::Sin(alpha);
1405 xyz1[1] = r*TMath::Sin(alpha)-y*TMath::Cos(alpha);
1408 AliKalmanTrack::MeanMaterialBudget(xyz0,xyz1,param);
1410 if (param[1]<=0) param[1] =100000000;
1411 PropagateTo(r,param[1],param[0]);
1417 //_____________________________________________________________________________
1418 Int_t AliTRDtrack::GetSector() const
1421 // Return the current sector
1424 return Int_t(TVector2::Phi_0_2pi(fAlpha)
1425 / AliTRDgeometry::GetAlpha())
1426 % AliTRDgeometry::kNsect;
1430 //_____________________________________________________________________________
1431 Double_t AliTRDtrack::Get1Pt() const
1437 return (TMath::Sign(1e-9,fC) + fC)*GetLocalConvConst();
1441 //_____________________________________________________________________________
1442 Double_t AliTRDtrack::GetP() const
1445 // Returns the total momentum
1448 return TMath::Abs(GetPt())*sqrt(1.+GetTgl()*GetTgl());
1452 //_____________________________________________________________________________
1453 Double_t AliTRDtrack::GetYat(Double_t xk) const
1456 // This function calculates the Y-coordinate of a track at
1457 // the plane x = xk.
1458 // Needed for matching with the TOF (I.Belikov)
1461 Double_t c1 = fC*fX - fE;
1462 Double_t r1 = TMath::Sqrt(1.0 - c1*c1);
1463 Double_t c2 = fC*xk - fE;
1464 Double_t r2 = TMath::Sqrt(1.0- c2*c2);
1465 return fY + (xk-fX)*(c1+c2)/(r1+r2);
1469 //_____________________________________________________________________________
1470 void AliTRDtrack::SetSampledEdx(Float_t q, Int_t i)
1473 // The sampled energy loss
1476 Double_t s = GetSnp();
1477 Double_t t = GetTgl();
1478 q *= TMath::Sqrt((1-s*s)/(1+t*t));
1483 //_____________________________________________________________________________
1484 void AliTRDtrack::SetSampledEdx(Float_t q)
1487 // The sampled energy loss
1490 Double_t s = GetSnp();
1491 Double_t t = GetTgl();
1492 q*= TMath::Sqrt((1-s*s)/(1+t*t));
1498 //_____________________________________________________________________________
1499 void AliTRDtrack::GetXYZ(Float_t r[3]) const
1502 //---------------------------------------------------------------------
1503 // Returns the position of the track in the global coord. system
1504 //---------------------------------------------------------------------
1506 Double_t cs = TMath::Cos(fAlpha);
1507 Double_t sn = TMath::Sin(fAlpha);
1508 r[0] = fX*cs - fY*sn;
1509 r[1] = fX*sn + fY*cs;