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>
21 #include "AliESDtrack.h"
22 #include "AliTRDgeometry.h"
23 #include "AliTRDcluster.h"
24 #include "AliTRDtrack.h"
25 #include "AliTRDtracklet.h"
29 ///////////////////////////////////////////////////////////////////////////////
31 // Represents a reconstructed TRD track //
32 // Local TRD Kalman track //
34 ///////////////////////////////////////////////////////////////////////////////
36 AliTRDtrack::AliTRDtrack():
77 for (Int_t i=0; i<kNplane; i++) {
81 for (UInt_t i=0; i<kMAXCLUSTERSPERTRACK; i++) {
86 for (Int_t i=0; i<3; i++) fBudget[i] = 0;
88 //_____________________________________________________________________________
89 AliTRDtrack::AliTRDtrack(const AliTRDcluster *c, UInt_t index,
90 const Double_t xx[5], const Double_t cc[15],
91 Double_t xref, Double_t alpha) : AliKalmanTrack() {
92 //-----------------------------------------------------------------
93 // This is the main track constructor.
94 //-----------------------------------------------------------------
99 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
100 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
104 fY=xx[0]; fZ=xx[1]; fE=xx[2]; fT=xx[3]; fC=xx[4];
106 SaveLocalConvConst();
109 fCzy=cc[1]; fCzz=cc[2];
110 fCey=cc[3]; fCez=cc[4]; fCee=cc[5];
111 fCty=cc[6]; fCtz=cc[7]; fCte=cc[8]; fCtt=cc[9];
112 fCcy=cc[10]; fCcz=cc[11]; fCce=cc[12]; fCct=cc[13]; fCcc=cc[14];
115 SetNumberOfClusters(1);
120 for (Int_t i=0;i<kNplane;i++){
122 fTimBinPlane[i] = -1;
135 Double_t q = TMath::Abs(c->GetQ());
136 Double_t s = fX*fC - fE, t=fT;
137 if(s*s < 1) q *= TMath::Sqrt((1-s*s)/(1+t*t));
141 // initialisation [SR, GSI 18.02.2003] (i startd for 1)
142 for(UInt_t i=1; i<kMAXCLUSTERSPERTRACK; i++) {
145 fIndexBackup[i] = 0; //backup indexes MI
147 for (Int_t i=0;i<3;i++) { fBudget[i]=0;};
153 //_____________________________________________________________________________
154 AliTRDtrack::AliTRDtrack(const AliTRDtrack& t) : AliKalmanTrack(t)
160 SetLabel(t.GetLabel());
161 fSeedLab=t.GetSeedLabel();
163 SetChi2(t.GetChi2());
167 for (Int_t i=0;i<kNplane;i++){
168 fdEdxPlane[i] = t.fdEdxPlane[i];
169 fTimBinPlane[i] = t.fTimBinPlane[i];
170 fTracklets[i] = t.fTracklets[i];
175 fNRotate = t.fNRotate;
176 fStopped = t.fStopped;
178 fNExpected = t.fNExpected;
179 fNExpectedLast = t.fNExpectedLast;
182 fChi2Last = t.fChi2Last;
188 fY=t.fY; fZ=t.fZ; fE=t.fE; fT=t.fT; fC=t.fC;
191 fCzy=t.fCzy; fCzz=t.fCzz;
192 fCey=t.fCey; fCez=t.fCez; fCee=t.fCee;
193 fCty=t.fCty; fCtz=t.fCtz; fCte=t.fCte; fCtt=t.fCtt;
194 fCcy=t.fCcy; fCcz=t.fCcz; fCce=t.fCce; fCct=t.fCct; fCcc=t.fCcc;
196 Int_t n=t.GetNumberOfClusters();
197 SetNumberOfClusters(n);
198 for (Int_t i=0; i<n; i++) {
199 fIndex[i]=t.fIndex[i];
200 fIndexBackup[i]=t.fIndex[i]; // MI - backup indexes
204 // initialisation (i starts from n) [SR, GSI, 18.02.2003]
205 for(UInt_t i=n; i<kMAXCLUSTERSPERTRACK; i++) {
208 fIndexBackup[i] = 0; //MI backup indexes
210 for (Int_t i=0;i<6;i++){
211 fTracklets[i] = t.fTracklets[i];
213 for (Int_t i=0;i<3;i++) { fBudget[i]=t.fBudget[i];};
216 //_____________________________________________________________________________
217 AliTRDtrack::AliTRDtrack(const AliKalmanTrack& t, Double_t alpha)
221 // Constructor from AliTPCtrack or AliITStrack .
224 SetLabel(t.GetLabel());
226 SetMass(t.GetMass());
227 SetNumberOfClusters(0);
229 fdEdx=t.GetPIDsignal();
231 for (Int_t i=0;i<kNplane;i++){
233 fTimBinPlane[i] = -1;
249 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
250 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
252 Double_t x, p[5]; t.GetExternalParameters(x,p);
258 fT=p[3]; x=GetLocalConvConst();
262 //Conversion of the covariance matrix
263 Double_t c[15]; t.GetExternalCovariance(c);
265 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
267 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
268 Double_t c32=fX*c[13] - c[8];
269 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
272 fCzy=c[1 ]; fCzz=c[2 ];
273 fCey=c20; fCez=c21; fCee=c22;
274 fCty=c[6 ]; fCtz=c[7 ]; fCte=c32; fCtt=c[9 ];
275 fCcy=c[10]; fCcz=c[11]; fCce=c42; fCct=c[13]; fCcc=c[14];
277 // Initialization [SR, GSI, 18.02.2003]
278 for(UInt_t i=0; i<kMAXCLUSTERSPERTRACK; i++) {
281 fIndexBackup[i] = 0; // MI backup indexes
284 for (Int_t i=0;i<3;i++) { fBudget[i]=0;};
287 //_____________________________________________________________________________
288 AliTRDtrack::AliTRDtrack(const AliESDtrack& t)
292 // Constructor from AliESDtrack
295 SetLabel(t.GetLabel());
297 SetMass(t.GetMass());
298 SetNumberOfClusters(t.GetTRDclusters(fIndex));
299 Int_t ncl = t.GetTRDclusters(fIndexBackup);
300 for (UInt_t i=ncl;i<kMAXCLUSTERSPERTRACK;i++) {
302 fIndex[i] = 0; //MI store indexes
304 fdEdx=t.GetTRDsignal();
306 for (Int_t i=0;i<kNplane;i++){
307 fdEdxPlane[i] = t.GetTRDsignals(i);
308 fTimBinPlane[i] = t.GetTRDTimBin(i);
323 fAlpha = t.GetAlpha();
324 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
325 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
327 Double_t x, p[5]; t.GetExternalParameters(x,p);
328 //Conversion of the covariance matrix
329 Double_t c[15]; t.GetExternalCovariance(c);
330 if (t.GetStatus()&AliESDtrack::kTRDbackup){
331 t.GetOuterExternalParameters(fAlpha,x,p);
332 t.GetOuterExternalCovariance(c);
333 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
334 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
340 fZ=p[1]; SaveLocalConvConst();
341 fT=p[3]; x=GetLocalConvConst();
346 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
348 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
349 Double_t c32=fX*c[13] - c[8];
350 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
353 fCzy=c[1 ]; fCzz=c[2 ];
354 fCey=c20; fCez=c21; fCee=c22;
355 fCty=c[6 ]; fCtz=c[7 ]; fCte=c32; fCtt=c[9 ];
356 fCcy=c[10]; fCcz=c[11]; fCce=c42; fCct=c[13]; fCcc=c[14];
358 // Initialization [SR, GSI, 18.02.2003]
359 for(UInt_t i=0; i<kMAXCLUSTERSPERTRACK; i++) {
361 // fIndex[i] = 0; //MI store indexes
364 for (Int_t i=0;i<3;i++) { fBudget[i]=0;};
365 if ((t.GetStatus()&AliESDtrack::kTIME) == 0) return;
367 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
368 SetIntegratedLength(t.GetIntegratedLength());
372 //____________________________________________________________________________
373 AliTRDtrack::~AliTRDtrack()
379 if (fBackupTrack) delete fBackupTrack;
384 //____________________________________________________________________________
385 AliTRDtrack &AliTRDtrack::operator=(const AliTRDtrack &t)
388 // Assignment operator
403 fAlpha = t.GetAlpha();
404 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
405 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
411 // //____________________________________________________________________________
412 // AliTRDtrack * AliTRDtrack::MakeTrack(const AliTrackReference *ref, Double_t mass)
415 // // Make dummy track from the track reference
416 // // negative mass means opposite charge
420 // for (Int_t i=0;i<15;i++) cc[i]=0;
421 // Double_t x = ref->X(), y = ref->Y(), z = ref->Z();
422 // Double_t alpha = TMath::ATan2(y,x);
423 // Double_t xr = TMath::Sqrt(x*x+y*y);
426 // xx[3] = ref->Pz()/ref->Pt();
428 // Float_t xyz[3]={x,y,z};
429 // Float_t convConst = 0;
430 // (AliKalmanTrack::GetFieldMap())->Field(xyz,b);
431 // convConst=1000/0.299792458/(1e-13 - b[2]);
432 // xx[4] = 1./(convConst*ref->Pt());
433 // if (mass<0) xx[4]*=-1.; // negative mass - negative direction
434 // Double_t lcos = (x*ref->Px()+y*ref->Py())/(xr*ref->Pt());
435 // Double_t lsin = TMath::Sin(TMath::ACos(lcos));
436 // if (mass<0) lsin*=-1.;
437 // xx[2] = xr*xx[4]-lsin;
439 // AliTRDtrack * track = new AliTRDtrack(&cl,100,xx,cc,xr,alpha);
440 // track->SetMass(TMath::Abs(mass));
441 // track->StartTimeIntegral();
445 //____________________________________________________________________________
446 Float_t AliTRDtrack::StatusForTOF()
449 // Defines the status of the TOF extrapolation
452 Float_t res = (0.2 + 0.8*(fN/(fNExpected+5.)))*(0.4+0.6*fTracklets[5].GetN()/20.);
453 res *= (0.25+0.8*40./(40.+fBudget[2]));
457 if (GetNumberOfClusters()<20) return 0; //
458 if (fN>110&&fChi2/(Float_t(fN))<3) return 3; //gold
459 if (fNLast>30&&fChi2Last/(Float_t(fNLast))<3) return 3; //gold
460 if (fNLast>20&&fChi2Last/(Float_t(fNLast))<2) return 3; //gold
461 if (fNLast/(fNExpectedLast+3.)>0.8 && fChi2Last/Float_t(fNLast)<5&&fNLast>20) return 2; //silber
462 if (fNLast>5 &&((fNLast+1.)/(fNExpectedLast+1.))>0.8&&fChi2Last/(fNLast-5.)<6) return 1;
468 //____________________________________________________________________________
469 void AliTRDtrack::GetExternalParameters(Double_t& xr, Double_t x[5]) const
472 // This function returns external TRD track representation
484 //_____________________________________________________________________________
485 void AliTRDtrack::GetExternalCovariance(Double_t cc[15]) const
488 // This function returns external representation of the covriance matrix.
491 Double_t a=GetLocalConvConst();
493 Double_t c22=fX*fX*fCcc-2*fX*fCce+fCee;
494 Double_t c32=fX*fCct-fCte;
495 Double_t c20=fX*fCcy-fCey, c21=fX*fCcz-fCez, c42=fX*fCcc-fCce;
498 cc[1 ]=fCzy; cc[2 ]=fCzz;
499 cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22;
500 cc[6 ]=fCty; cc[7 ]=fCtz; cc[8 ]=c32; cc[9 ]=fCtt;
501 cc[10]=fCcy*a; cc[11]=fCcz*a; cc[12]=c42*a; cc[13]=fCct*a; cc[14]=fCcc*a*a;
505 //_____________________________________________________________________________
506 void AliTRDtrack::GetCovariance(Double_t cc[15]) const
509 // Returns the track covariance matrix
513 cc[1]=fCzy; cc[2]=fCzz;
514 cc[3]=fCey; cc[4]=fCez; cc[5]=fCee;
515 cc[6]=fCcy; cc[7]=fCcz; cc[8]=fCce; cc[9]=fCcc;
516 cc[10]=fCty; cc[11]=fCtz; cc[12]=fCte; cc[13]=fCct; cc[14]=fCtt;
520 //_____________________________________________________________________________
521 Int_t AliTRDtrack::Compare(const TObject *o) const
524 // Compares tracks according to their Y2 or curvature
527 AliTRDtrack *t=(AliTRDtrack*)o;
528 // Double_t co=t->GetSigmaY2();
529 // Double_t c =GetSigmaY2();
531 Double_t co=TMath::Abs(t->GetC());
532 Double_t c =TMath::Abs(GetC());
535 else if (c<co) return -1;
540 //_____________________________________________________________________________
541 void AliTRDtrack::CookdEdx(Double_t low, Double_t up) {
542 //-----------------------------------------------------------------
543 // Calculates dE/dX within the "low" and "up" cuts.
544 //-----------------------------------------------------------------
547 //Int_t nc=GetNumberOfClusters();
554 Float_t sorted[kMAXCLUSTERSPERTRACK];
555 for (i=0; i < nc; i++) {
558 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc);
560 //for (i=nl; i<=nu; i++) dedx += sorted[i];
562 for (i=0; i<nc; i++) dedx += sorted[i]; // ADDED by PS
563 if((nu-nl)) dedx /= (nu-nl); // ADDED by PS
567 // now real truncated mean
568 for (i=0; i < nc; i++) {
569 sorted[i]=TMath::Abs(fdQdl[i]);
571 Int_t * index = new Int_t[nc];
572 TMath::Sort(nc, sorted, index,kFALSE);
574 for (i=nl; i<=nu; i++) dedx += sorted[index[i]];
582 //_____________________________________________________________________________
583 Int_t AliTRDtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho)
585 // Propagates a track of particle with mass=pm to a reference plane
586 // defined by x=xk through media of density=rho and radiationLength=x0
588 if (xk == fX) return 1;
590 if (TMath::Abs(fC*xk - fE) >= 0.90000) {
591 // Int_t n=GetNumberOfClusters();
592 //if (n>4) cerr << n << " AliTRDtrack: Propagation failed, \tPt = "
593 // << GetPt() << "\t" << GetLabel() << "\t" << GetMass() << endl;
596 Double_t lcc=GetLocalConvConst();
598 // track Length measurement [SR, GSI, 17.02.2003]
599 Double_t oldX = fX, oldY = fY, oldZ = fZ;
601 Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fY, z1=fZ;
602 Double_t c1=fC*x1 - fE;
603 if((c1*c1) > 1) return 0;
604 Double_t r1=sqrt(1.- c1*c1);
605 Double_t c2=fC*x2 - fE;
606 if((c2*c2) > 1) return 0;
607 Double_t r2=sqrt(1.- c2*c2);
609 fY += dx*(c1+c2)/(r1+r2);
610 fZ += dx*(c1+c2)/(c1*r2 + c2*r1)*fT;
613 Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
614 Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
615 Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
616 Double_t cr=c1*r2+c2*r1;
617 Double_t f12=-dx*fT*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
618 Double_t f13= dx*cc/cr;
619 Double_t f14=dx*fT*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);
622 Double_t b00=f02*fCey + f04*fCcy, b01=f12*fCey + f14*fCcy + f13*fCty;
623 Double_t b10=f02*fCez + f04*fCcz, b11=f12*fCez + f14*fCcz + f13*fCtz;
624 Double_t b20=f02*fCee + f04*fCce, b21=f12*fCee + f14*fCce + f13*fCte;
625 Double_t b30=f02*fCte + f04*fCct, b31=f12*fCte + f14*fCct + f13*fCtt;
626 Double_t b40=f02*fCce + f04*fCcc, b41=f12*fCce + f14*fCcc + f13*fCct;
629 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31;
631 //F*C*Ft = C + (a + b + bt)
633 fCzy += a01 + b01 + b10;
644 //Change of the magnetic field *************
645 SaveLocalConvConst();
647 fC*=lcc/GetLocalConvConst();
650 //Multiple scattering ******************
651 Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fY)*(y1-fY)+(z1-fZ)*(z1-fZ));
652 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
653 Double_t beta2=p2/(p2 + GetMass()*GetMass());
654 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
656 Double_t ey=fC*fX - fE, ez=fT;
657 Double_t xz=fC*ez, zz1=ez*ez+1, xy=fE+ey;
659 fCee += (2*ey*ez*ez*fE+1-ey*ey+ez*ez+fE*fE*ez*ez)*theta2;
660 fCte += ez*zz1*xy*theta2;
661 fCtt += zz1*zz1*theta2;
662 fCce += xz*ez*xy*theta2;
663 fCct += xz*zz1*theta2;
664 fCcc += xz*xz*theta2;
666 Double_t dc22 = (1-ey*ey+xz*xz*fX*fX)*theta2;
667 Double_t dc32 = (xz*fX*zz1)*theta2;
668 Double_t dc33 = (zz1*zz1)*theta2;
669 Double_t dc42 = (xz*fX*xz)*theta2;
670 Double_t dc43 = (zz1*xz)*theta2;
671 Double_t dc44 = (xz*xz)*theta2;
679 //Energy losses************************
680 if((5940*beta2/(1-beta2+1e-10) - beta2) < 0) return 0;
682 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2+1e-10)) - beta2)*d*rho;
683 Float_t budget = d* rho;
686 // suspicious part - think about it ?
687 Double_t kinE = TMath::Sqrt(p2);
688 if (dE>0.8*kinE) dE = 0.8*kinE; //
689 if (dE<0) dE = 0.0; // not valid region for Bethe bloch
695 fC*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
697 // Double_t sigmade = 0.1*dE*TMath::Sqrt(TMath::Sqrt(1+fT*fT)*90./(d+0.0001)); // 20 percent fluctuation - normalized to some length
698 Double_t sigmade = 0.07*TMath::Sqrt(TMath::Abs(dE)); // energy loss fluctuation
699 Double_t sigmac2 = sigmade*sigmade*fC*fC*(p2+GetMass()*GetMass())/(p2*p2);
701 fCee += fX*fX*sigmac2;
703 // track time measurement [SR, GSI 17.02.2002]
705 if (IsStartedTimeIntegral()) {
706 Double_t l2 = TMath::Sqrt((fX-oldX)*(fX-oldX) + (fY-oldY)*(fY-oldY) + (fZ-oldZ)*(fZ-oldZ));
707 if (TMath::Abs(l2*fC)>0.0001){
708 // make correction for curvature if neccesary
709 l2 = 0.5*TMath::Sqrt((fX-oldX)*(fX-oldX) + (fY-oldY)*(fY-oldY));
710 l2 = 2*TMath::ASin(l2*fC)/fC;
711 l2 = TMath::Sqrt(l2*l2+(fZ-oldZ)*(fZ-oldZ));
719 //_____________________________________________________________________________
720 Int_t AliTRDtrack::Update(const AliTRDcluster *c, Double_t chisq, UInt_t index
723 // Assignes found cluster to the track and updates track information
725 Bool_t fNoTilt = kTRUE;
726 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
727 // add angular effect to the error contribution - MI
728 Float_t tangent2 = (fC*fX-fE)*(fC*fX-fE);
729 if (tangent2 < 0.90000){
730 tangent2 = tangent2/(1.-tangent2);
732 Float_t errang = tangent2*0.04; //
733 Float_t padlength = TMath::Sqrt(c->GetSigmaZ2()*12.);
735 Double_t r00=c->GetSigmaY2() +errang, r01=0., r11=c->GetSigmaZ2()*100.;
736 r00+=fCyy; r01+=fCzy; r11+=fCzz;
737 Double_t det=r00*r11 - r01*r01;
738 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
740 Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
741 Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
742 Double_t k20=fCey*r00+fCez*r01, k21=fCey*r01+fCez*r11;
743 Double_t k30=fCty*r00+fCtz*r01, k31=fCty*r01+fCtz*r11;
744 Double_t k40=fCcy*r00+fCcz*r01, k41=fCcy*r01+fCcz*r11;
746 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
747 Double_t cur=fC + k40*dy + k41*dz, eta=fE + k20*dy + k21*dz;
751 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
752 // Int_t n=GetNumberOfClusters();
753 //if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
756 fY += k00*dy + k01*dz;
757 fZ += k10*dy + k11*dz;
759 //fT += k30*dy + k31*dz;
763 Double_t xuFactor = 100.; // empirical factor set by C.Xu
764 // in the first tilt version
765 dy=c->GetY() - fY; dz=c->GetZ() - fZ;
768 if (TMath::Abs(dz)>padlength/2.){
769 Float_t dy2 = c->GetY() - fY;
770 Float_t sign = (dz>0) ? -1.: 1.;
771 dy2+=h01*sign*padlength/2.;
778 r00=c->GetSigmaY2()+errang+add, r01=0., r11=c->GetSigmaZ2()*xuFactor;
779 r00+=(fCyy+2.0*h01*fCzy+h01*h01*fCzz);
780 r01+=(fCzy+h01*fCzz);
783 det=r00*r11 - r01*r01;
784 tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
786 k00=fCyy*r00+fCzy*(r01+h01*r00),k01=fCyy*r01+fCzy*(r11+h01*r01);
787 k10=fCzy*r00+fCzz*(r01+h01*r00),k11=fCzy*r01+fCzz*(r11+h01*r01);
788 k20=fCey*r00+fCez*(r01+h01*r00),k21=fCey*r01+fCez*(r11+h01*r01);
789 k30=fCty*r00+fCtz*(r01+h01*r00),k31=fCty*r01+fCtz*(r11+h01*r01);
790 k40=fCcy*r00+fCcz*(r01+h01*r00),k41=fCcy*r01+fCcz*(r11+h01*r01);
793 cur=fC + k40*dy + k41*dz; eta=fE + k20*dy + k21*dz;
794 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
795 // Int_t n=GetNumberOfClusters();
796 //if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
799 fY += k00*dy + k01*dz;
800 fZ += k10*dy + k11*dz;
802 fT += k30*dy + k31*dz;
812 Double_t c01=fCzy, c02=fCey, c03=fCty, c04=fCcy;
813 Double_t c12=fCez, c13=fCtz, c14=fCcz;
816 fCyy-=k00*fCyy+k01*fCzy; fCzy-=k00*c01+k01*fCzz;
817 fCey-=k00*c02+k01*c12; fCty-=k00*c03+k01*c13;
818 fCcy-=k00*c04+k01*c14;
820 fCzz-=k10*c01+k11*fCzz;
821 fCez-=k10*c02+k11*c12; fCtz-=k10*c03+k11*c13;
822 fCcz-=k10*c04+k11*c14;
824 fCee-=k20*c02+k21*c12; fCte-=k20*c03+k21*c13;
825 fCce-=k20*c04+k21*c14;
827 fCtt-=k30*c03+k31*c13;
828 fCct-=k40*c03+k41*c13;
829 //fCct-=k30*c04+k31*c14; // symmetric formula MI
831 fCcc-=k40*c04+k41*c14;
833 Int_t n=GetNumberOfClusters();
835 SetNumberOfClusters(n+1);
837 SetChi2(GetChi2()+chisq);
838 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
844 //_____________________________________________________________________________
845 Int_t AliTRDtrack::UpdateMI(const AliTRDcluster *c, Double_t chisq, UInt_t index, Double_t h01,
848 // Assignes found cluster to the track and updates track information
850 Bool_t fNoTilt = kTRUE;
851 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
852 // add angular effect to the error contribution and make correction - MI
853 //AliTRDclusterCorrection *corrector = AliTRDclusterCorrection::GetCorrection();
855 Double_t tangent2 = (fC*fX-fE)*(fC*fX-fE);
856 if (tangent2 < 0.90000){
857 tangent2 = tangent2/(1.-tangent2);
859 Double_t tangent = TMath::Sqrt(tangent2);
860 if ((fC*fX-fE)<0) tangent*=-1;
861 // Double_t correction = 0*plane;
862 Double_t errang = tangent2*0.04; //
863 Double_t errsys =0.025*0.025*20; //systematic error part
865 if (c->GetNPads()==4) extend=2;
866 //if (c->GetNPads()==5) extend=3;
867 //if (c->GetNPads()==6) extend=3;
868 //if (c->GetQ()<15) return 1;
873 correction = corrector->GetCorrection(plane,c->GetLocalTimeBin(),tangent);
874 if (TMath::Abs(correction)>0){
876 errang = corrector->GetSigma(plane,c->GetLocalTimeBin(),tangent);
878 errang += tangent2*0.04;
883 // Double_t padlength = TMath::Sqrt(c->GetSigmaZ2()*12.);
885 Double_t r00=(c->GetSigmaY2() +errang+errsys)*extend, r01=0., r11=c->GetSigmaZ2()*10000.;
886 r00+=fCyy; r01+=fCzy; r11+=fCzz;
887 Double_t det=r00*r11 - r01*r01;
888 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
890 Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
891 Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
892 Double_t k20=fCey*r00+fCez*r01, k21=fCey*r01+fCez*r11;
893 Double_t k30=fCty*r00+fCtz*r01, k31=fCty*r01+fCtz*r11;
894 Double_t k40=fCcy*r00+fCcz*r01, k41=fCcy*r01+fCcz*r11;
896 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
897 Double_t cur=fC + k40*dy + k41*dz, eta=fE + k20*dy + k21*dz;
901 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
902 // Int_t n=GetNumberOfClusters();
903 //if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
906 fY += k00*dy + k01*dz;
907 fZ += k10*dy + k11*dz;
909 //fT += k30*dy + k31*dz;
913 Double_t padlength = TMath::Sqrt(c->GetSigmaZ2()*12);
915 Double_t xuFactor = 1000.; // empirical factor set by C.Xu
916 // in the first tilt version
917 dy=c->GetY() - fY; dz=c->GetZ() - fZ;
918 //dy=dy+h01*dz+correction;
920 Double_t tiltdz = dz;
921 if (TMath::Abs(tiltdz)>padlength/2.) {
922 tiltdz = TMath::Sign(padlength/2,dz);
928 if (TMath::Abs(dz)>padlength/2.){
929 //Double_t dy2 = c->GetY() - fY;
930 //Double_t sign = (dz>0) ? -1.: 1.;
931 //dy2-=h01*sign*padlength/2.;
935 Double_t s00 = (c->GetSigmaY2()+errang)*extend+errsys+add; // error pad
936 Double_t s11 = c->GetSigmaZ2()*xuFactor; // error pad-row
938 r00 = fCyy + 2*fCzy*h01 + fCzz*h01*h01+s00;
939 r01 = fCzy + fCzz*h01;
941 det = r00*r11 - r01*r01;
943 tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
946 k00=fCyy*r00+fCzy*(r01+h01*r00),k01=fCyy*r01+fCzy*(r11+h01*r01);
947 k10=fCzy*r00+fCzz*(r01+h01*r00),k11=fCzy*r01+fCzz*(r11+h01*r01);
948 k20=fCey*r00+fCez*(r01+h01*r00),k21=fCey*r01+fCez*(r11+h01*r01);
949 k30=fCty*r00+fCtz*(r01+h01*r00),k31=fCty*r01+fCtz*(r11+h01*r01);
950 k40=fCcy*r00+fCcz*(r01+h01*r00),k41=fCcy*r01+fCcz*(r11+h01*r01);
953 cur=fC + k40*dy + k41*dz; eta=fE + k20*dy + k21*dz;
954 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
955 //Int_t n=GetNumberOfClusters();
956 // if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
959 fY += k00*dy + k01*dz;
960 fZ += k10*dy + k11*dz;
962 fT += k30*dy + k31*dz;
975 Double_t oldyy = fCyy, oldzz = fCzz; //, oldee=fCee, oldcc =fCcc;
976 Double_t oldzy = fCzy, oldey = fCey, oldty=fCty, oldcy =fCcy;
977 Double_t oldez = fCez, oldtz = fCtz, oldcz=fCcz;
978 //Double_t oldte = fCte, oldce = fCce;
979 //Double_t oldct = fCct;
981 fCyy-=k00*oldyy+k01*oldzy;
982 fCzy-=k10*oldyy+k11*oldzy;
983 fCey-=k20*oldyy+k21*oldzy;
984 fCty-=k30*oldyy+k31*oldzy;
985 fCcy-=k40*oldyy+k41*oldzy;
987 fCzz-=k10*oldzy+k11*oldzz;
988 fCez-=k20*oldzy+k21*oldzz;
989 fCtz-=k30*oldzy+k31*oldzz;
990 fCcz-=k40*oldzy+k41*oldzz;
992 fCee-=k20*oldey+k21*oldez;
993 fCte-=k30*oldey+k31*oldez;
994 fCce-=k40*oldey+k41*oldez;
996 fCtt-=k30*oldty+k31*oldtz;
997 fCct-=k40*oldty+k41*oldtz;
999 fCcc-=k40*oldcy+k41*oldcz;
1002 Int_t n=GetNumberOfClusters();
1004 SetNumberOfClusters(n+1);
1006 SetChi2(GetChi2()+chisq);
1007 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
1013 //_____________________________________________________________________________
1014 Int_t AliTRDtrack::UpdateMI(const AliTRDtracklet &tracklet)
1017 // Assignes found tracklet to the track and updates track information
1020 Double_t r00=(tracklet.GetTrackletSigma2()), r01=0., r11= 10000.;
1021 r00+=fCyy; r01+=fCzy; r11+=fCzz;
1023 Double_t det=r00*r11 - r01*r01;
1024 Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
1027 Double_t dy=tracklet.GetY() - fY, dz=tracklet.GetZ() - fZ;
1030 Double_t s00 = tracklet.GetTrackletSigma2(); // error pad
1031 Double_t s11 = 100000; // error pad-row
1032 Float_t h01 = tracklet.GetTilt();
1034 // r00 = fCyy + 2*fCzy*h01 + fCzz*h01*h01+s00;
1035 r00 = fCyy + fCzz*h01*h01+s00;
1036 // r01 = fCzy + fCzz*h01;
1039 det = r00*r11 - r01*r01;
1041 tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
1043 Double_t k00=fCyy*r00+fCzy*r01, k01=fCyy*r01+fCzy*r11;
1044 Double_t k10=fCzy*r00+fCzz*r01, k11=fCzy*r01+fCzz*r11;
1045 Double_t k20=fCey*r00+fCez*r01, k21=fCey*r01+fCez*r11;
1046 Double_t k30=fCty*r00+fCtz*r01, k31=fCty*r01+fCtz*r11;
1047 Double_t k40=fCcy*r00+fCcz*r01, k41=fCcy*r01+fCcz*r11;
1050 // k00=fCyy*r00+fCzy*(r01+h01*r00),k01=fCyy*r01+fCzy*(r11+h01*r01);
1051 // k10=fCzy*r00+fCzz*(r01+h01*r00),k11=fCzy*r01+fCzz*(r11+h01*r01);
1052 // k20=fCey*r00+fCez*(r01+h01*r00),k21=fCey*r01+fCez*(r11+h01*r01);
1053 // k30=fCty*r00+fCtz*(r01+h01*r00),k31=fCty*r01+fCtz*(r11+h01*r01);
1054 // k40=fCcy*r00+fCcz*(r01+h01*r00),k41=fCcy*r01+fCcz*(r11+h01*r01);
1056 //Update measurement
1057 Double_t cur=fC + k40*dy + k41*dz, eta=fE + k20*dy + k21*dz;
1058 // cur=fC + k40*dy + k41*dz; eta=fE + k20*dy + k21*dz;
1059 if (TMath::Abs(cur*fX-eta) >= 0.90000) {
1060 //Int_t n=GetNumberOfClusters();
1061 // if (n>4) cerr<<n<<" AliTRDtrack warning: Filtering failed !\n";
1071 fY += k00*dy + k01*dz;
1072 fZ += k10*dy + k11*dz;
1074 fT += k30*dy + k31*dz;
1081 Double_t oldyy = fCyy, oldzz = fCzz; //, oldee=fCee, oldcc =fCcc;
1082 Double_t oldzy = fCzy, oldey = fCey, oldty=fCty, oldcy =fCcy;
1083 Double_t oldez = fCez, oldtz = fCtz, oldcz=fCcz;
1084 //Double_t oldte = fCte, oldce = fCce;
1085 //Double_t oldct = fCct;
1087 fCyy-=k00*oldyy+k01*oldzy;
1088 fCzy-=k10*oldyy+k11*oldzy;
1089 fCey-=k20*oldyy+k21*oldzy;
1090 fCty-=k30*oldyy+k31*oldzy;
1091 fCcy-=k40*oldyy+k41*oldzy;
1093 fCzz-=k10*oldzy+k11*oldzz;
1094 fCez-=k20*oldzy+k21*oldzz;
1095 fCtz-=k30*oldzy+k31*oldzz;
1096 fCcz-=k40*oldzy+k41*oldzz;
1098 fCee-=k20*oldey+k21*oldez;
1099 fCte-=k30*oldey+k31*oldez;
1100 fCce-=k40*oldey+k41*oldez;
1102 fCtt-=k30*oldty+k31*oldtz;
1103 fCct-=k40*oldty+k41*oldtz;
1105 fCcc-=k40*oldcy+k41*oldcz;
1108 Int_t n=GetNumberOfClusters();
1110 SetNumberOfClusters(n+1);
1112 SetChi2(GetChi2()+chisq);
1113 // cerr<<"in update: fIndex["<<fN<<"] = "<<index<<endl;
1120 //_____________________________________________________________________________
1121 Int_t AliTRDtrack::Rotate(Double_t alpha, Bool_t absolute)
1123 // Rotates track parameters in R*phi plane
1124 // if absolute rotation alpha is in global system
1125 // otherwise alpha rotation is relative to the current rotation angle
1135 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
1136 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
1138 Double_t x1=fX, y1=fY;
1139 Double_t ca=cos(alpha), sa=sin(alpha);
1140 Double_t r1=fC*fX - fE;
1144 if((r1*r1) > 1) return 0;
1145 fE=fE*ca + (fC*y1 + sqrt(1.- r1*r1))*sa;
1147 Double_t r2=fC*fX - fE;
1148 if (TMath::Abs(r2) >= 0.90000) {
1149 Int_t n=GetNumberOfClusters();
1150 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !\n";
1154 if((r2*r2) > 1) return 0;
1155 Double_t y0=fY + sqrt(1.- r2*r2)/fC;
1156 if ((fY-y0)*fC >= 0.) {
1157 Int_t n=GetNumberOfClusters();
1158 if (n>4) cerr<<n<<" AliTRDtrack warning: Rotation failed !!!\n";
1163 Double_t f00=ca-1, f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa,
1164 f20=fC*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1;
1167 Double_t b00=fCyy*f00, b02=fCyy*f20+fCcy*f24+fCey*f22;
1168 Double_t b10=fCzy*f00, b12=fCzy*f20+fCcz*f24+fCez*f22;
1169 Double_t b20=fCey*f00, b22=fCey*f20+fCce*f24+fCee*f22;
1170 Double_t b30=fCty*f00, b32=fCty*f20+fCct*f24+fCte*f22;
1171 Double_t b40=fCcy*f00, b42=fCcy*f20+fCcc*f24+fCce*f22;
1174 Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22;
1176 //F*C*Ft = C + (a + b + bt)
1177 fCyy += a00 + 2*b00;
1179 fCey += a02+b20+b02;
1184 fCee += a22 + 2*b22;
1191 //_____________________________________________________________________________
1192 Double_t AliTRDtrack::GetPredictedChi2(const AliTRDcluster *c, Double_t h01) const
1195 // Returns the track chi2
1198 Bool_t fNoTilt = kTRUE;
1199 if(TMath::Abs(h01) > 0.003) fNoTilt = kFALSE;
1200 Double_t chi2, dy, r00, r01, r11;
1204 r00=c->GetSigmaY2();
1208 Double_t padlength = TMath::Sqrt(c->GetSigmaZ2()*12);
1210 r00=c->GetSigmaY2(); r01=0.; r11=c->GetSigmaZ2();
1211 r00+=fCyy; r01+=fCzy; r11+=fCzz;
1213 Double_t det=r00*r11 - r01*r01;
1214 if (TMath::Abs(det) < 1.e-10) {
1215 Int_t n=GetNumberOfClusters();
1216 if (n>4) cerr<<n<<" AliTRDtrack warning: Singular matrix !\n";
1219 Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
1220 Double_t dy=c->GetY() - fY, dz=c->GetZ() - fZ;
1221 Double_t tiltdz = dz;
1222 if (TMath::Abs(tiltdz)>padlength/2.) {
1223 tiltdz = TMath::Sign(padlength/2,dz);
1228 chi2 = (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
1235 //_________________________________________________________________________
1236 void AliTRDtrack::GetPxPyPz(Double_t& px, Double_t& py, Double_t& pz) const
1238 // Returns reconstructed track momentum in the global system.
1240 Double_t pt=TMath::Abs(GetPt()); // GeV/c
1241 Double_t r=fC*fX-fE;
1244 if(r > 1) { py = pt; px = 0; }
1245 else if(r < -1) { py = -pt; px = 0; }
1247 y0=fY + sqrt(1.- r*r)/fC;
1248 px=-pt*(fY-y0)*fC; //cos(phi);
1249 py=-pt*(fE-fX*fC); //sin(phi);
1252 Double_t tmp=px*TMath::Cos(fAlpha) - py*TMath::Sin(fAlpha);
1253 py=px*TMath::Sin(fAlpha) + py*TMath::Cos(fAlpha);
1258 //_________________________________________________________________________
1259 void AliTRDtrack::GetGlobalXYZ(Double_t& x, Double_t& y, Double_t& z) const
1261 // Returns reconstructed track coordinates in the global system.
1263 x = fX; y = fY; z = fZ;
1264 Double_t tmp=x*TMath::Cos(fAlpha) - y*TMath::Sin(fAlpha);
1265 y=x*TMath::Sin(fAlpha) + y*TMath::Cos(fAlpha);
1270 //_________________________________________________________________________
1271 void AliTRDtrack::ResetCovariance()
1274 // Resets covariance matrix
1279 fCey=0.; fCez=0.; fCee*=10.;
1280 fCty=0.; fCtz=0.; fCte=0.; fCtt*=10.;
1281 fCcy=0.; fCcz=0.; fCce=0.; fCct=0.; fCcc*=10.;
1285 //_____________________________________________________________________________
1286 void AliTRDtrack::ResetCovariance(Float_t mult)
1289 // Resets covariance matrix
1294 fCey*=0.; fCez*=0.; fCee*=mult;
1295 fCty*=0.; fCtz*=0.; fCte*=0.; fCtt*=1.;
1296 fCcy*=0.; fCcz*=0.; fCce*=0.; fCct*=0.; fCcc*=mult;
1300 //_____________________________________________________________________________
1301 void AliTRDtrack::MakeBackupTrack()
1304 // Creates a backup track
1307 if (fBackupTrack) delete fBackupTrack;
1308 fBackupTrack = new AliTRDtrack(*this);
1312 //_____________________________________________________________________________
1313 Int_t AliTRDtrack::GetProlongation(Double_t xk, Double_t &y, Double_t &z)
1316 // Find prolongation at given x
1317 // return 0 if not exist
1319 Double_t c1=fC*fX - fE;
1320 if (TMath::Abs(c1)>1.) return 0;
1321 Double_t r1=TMath::Sqrt(1.- c1*c1);
1322 Double_t c2=fC*xk - fE;
1323 if (TMath::Abs(c2)>1.) return 0;
1324 Double_t r2=TMath::Sqrt(1.- c2*c2);
1325 y =fY + (xk-fX)*(c1+c2)/(r1+r2);
1326 z =fZ + (xk-fX)*(c1+c2)/(c1*r2 + c2*r1)*fT;
1332 //_____________________________________________________________________________
1333 Int_t AliTRDtrack::PropagateToX(Double_t xr, Double_t step)
1336 // Propagate track to given x position
1337 // works inside of the 20 degree segmentation (local cooordinate frame for TRD , TPC, TOF)
1339 // material budget from geo manager
1341 Double_t xyz0[3], xyz1[3],y,z;
1342 const Double_t kAlphac = TMath::Pi()/9.;
1343 const Double_t kTalphac = TMath::Tan(kAlphac*0.5);
1344 // critical alpha - cross sector indication
1346 Double_t dir = (fX>xr) ? -1.:1.;
1348 for (Double_t x=fX+dir*step;dir*x<dir*xr;x+=dir*step){
1350 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1351 GetProlongation(x,y,z);
1352 xyz1[0] = x*TMath::Cos(fAlpha)+y*TMath::Sin(fAlpha);
1353 xyz1[1] = x*TMath::Sin(fAlpha)-y*TMath::Cos(fAlpha);
1356 AliKalmanTrack::MeanMaterialBudget(xyz0,xyz1,param);
1358 if (param[0]>0&¶m[1]>0) PropagateTo(x,param[1],param[0]);
1359 if (fY>fX*kTalphac){
1362 if (fY<-fX*kTalphac){
1373 //_____________________________________________________________________________
1374 Int_t AliTRDtrack::PropagateToR(Double_t r,Double_t step)
1377 // propagate track to the radial position
1378 // rotation always connected to the last track position
1380 Double_t xyz0[3], xyz1[3],y,z;
1381 Double_t radius = TMath::Sqrt(fX*fX+fY*fY);
1382 Double_t dir = (radius>r) ? -1.:1.; // direction +-
1384 for (Double_t x=radius+dir*step;dir*x<dir*r;x+=dir*step){
1385 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1386 Double_t alpha = TMath::ATan2(xyz0[1],xyz0[0]);
1387 Rotate(alpha,kTRUE);
1388 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1389 GetProlongation(x,y,z);
1390 xyz1[0] = x*TMath::Cos(alpha)+y*TMath::Sin(alpha);
1391 xyz1[1] = x*TMath::Sin(alpha)-y*TMath::Cos(alpha);
1394 AliKalmanTrack::MeanMaterialBudget(xyz0,xyz1,param);
1395 if (param[1]<=0) param[1] =100000000;
1396 PropagateTo(x,param[1],param[0]);
1398 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1399 Double_t alpha = TMath::ATan2(xyz0[1],xyz0[0]);
1400 Rotate(alpha,kTRUE);
1401 GetGlobalXYZ(xyz0[0],xyz0[1],xyz0[2]);
1402 GetProlongation(r,y,z);
1403 xyz1[0] = r*TMath::Cos(alpha)+y*TMath::Sin(alpha);
1404 xyz1[1] = r*TMath::Sin(alpha)-y*TMath::Cos(alpha);
1407 AliKalmanTrack::MeanMaterialBudget(xyz0,xyz1,param);
1409 if (param[1]<=0) param[1] =100000000;
1410 PropagateTo(r,param[1],param[0]);
1416 //_____________________________________________________________________________
1417 Int_t AliTRDtrack::GetSector() const
1420 // Return the current sector
1423 return Int_t(TVector2::Phi_0_2pi(fAlpha)
1424 / AliTRDgeometry::GetAlpha())
1425 % AliTRDgeometry::kNsect;
1429 //_____________________________________________________________________________
1430 Double_t AliTRDtrack::Get1Pt() const
1436 return (TMath::Sign(1e-9,fC) + fC)*GetLocalConvConst();
1440 //_____________________________________________________________________________
1441 Double_t AliTRDtrack::GetP() const
1444 // Returns the total momentum
1447 return TMath::Abs(GetPt())*sqrt(1.+GetTgl()*GetTgl());
1451 //_____________________________________________________________________________
1452 Double_t AliTRDtrack::GetYat(Double_t xk) const
1455 // This function calculates the Y-coordinate of a track at
1456 // the plane x = xk.
1457 // Needed for matching with the TOF (I.Belikov)
1460 Double_t c1 = fC*fX - fE;
1461 Double_t r1 = TMath::Sqrt(1.0 - c1*c1);
1462 Double_t c2 = fC*xk - fE;
1463 Double_t r2 = TMath::Sqrt(1.0- c2*c2);
1464 return fY + (xk-fX)*(c1+c2)/(r1+r2);
1468 //_____________________________________________________________________________
1469 void AliTRDtrack::SetSampledEdx(Float_t q, Int_t i)
1472 // The sampled energy loss
1475 Double_t s = GetSnp();
1476 Double_t t = GetTgl();
1477 q *= TMath::Sqrt((1-s*s)/(1+t*t));
1482 //_____________________________________________________________________________
1483 void AliTRDtrack::SetSampledEdx(Float_t q)
1486 // The sampled energy loss
1489 Double_t s = GetSnp();
1490 Double_t t = GetTgl();
1491 q*= TMath::Sqrt((1-s*s)/(1+t*t));
1497 //_____________________________________________________________________________
1498 void AliTRDtrack::GetXYZ(Float_t r[3]) const
1501 //---------------------------------------------------------------------
1502 // Returns the position of the track in the global coord. system
1503 //---------------------------------------------------------------------
1505 Double_t cs = TMath::Cos(fAlpha);
1506 Double_t sn = TMath::Sin(fAlpha);
1507 r[0] = fX*cs - fY*sn;
1508 r[1] = fX*sn + fY*cs;