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 ///////////////////////////////////////////////////////////////////////////
19 // Implementation of the ITS track class
21 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
22 // dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
23 ///////////////////////////////////////////////////////////////////////////
26 #include "AliCluster.h"
27 #include "AliESDVertex.h"
28 #include "AliITSReconstructor.h"
29 #include "AliITStrackV2.h"
30 #include "AliTracker.h"
32 const Int_t AliITStrackV2::fgkWARN = 5;
34 ClassImp(AliITStrackV2)
37 //____________________________________________________________________________
38 AliITStrackV2::AliITStrackV2() : AliKalmanTrack(),
39 fCheckInvariant(kTRUE),
43 for(Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) {fIndex[i]=-1; fModule[i]=-1;}
44 for(Int_t i=0; i<AliITSgeomTGeo::kNLayers; i++) {fSharedWeight[i]=0;}
45 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
49 //____________________________________________________________________________
50 AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c):
52 fCheckInvariant(kTRUE),
53 fdEdx(t.GetITSsignal()),
56 //------------------------------------------------------------------
57 // Conversion ESD track -> ITS track.
58 // If c==kTRUE, create the ITS track out of the constrained params.
59 //------------------------------------------------------------------
60 const AliExternalTrackParam *par=&t;
62 par=t.GetConstrainedParam();
63 if (!par) AliError("AliITStrackV2: conversion failed !\n");
65 Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance());
67 SetLabel(t.GetLabel());
69 SetNumberOfClusters(t.GetITSclusters(fIndex));
71 if (t.GetStatus()&AliESDtrack::kTIME) {
73 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
74 SetIntegratedLength(t.GetIntegratedLength());
77 for(Int_t i=0; i<AliITSgeomTGeo::kNLayers; i++) {fSharedWeight[i]=0;}
78 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
81 //____________________________________________________________________________
82 void AliITStrackV2::ResetClusters() {
83 //------------------------------------------------------------------
84 // Reset the array of attached clusters.
85 //------------------------------------------------------------------
86 for (Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) fIndex[i]=-1;
87 for (Int_t i=0; i<AliITSgeomTGeo::kNLayers; i++) {fSharedWeight[i]=0;}
89 SetNumberOfClusters(0);
92 //____________________________________________________________________________
93 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
94 // Update track params
95 fESDtrack->UpdateTrackParams(this,flags);
96 // copy the module indices
98 for(i=0;i<2*AliITSgeomTGeo::kNLayers;i++) {
99 // printf(" %d\n",GetModuleIndex(i));
100 fESDtrack->SetITSModuleIndex(i,GetModuleIndex(i));
102 // copy the map of shared clusters
103 if(flags==AliESDtrack::kITSin) {
104 UChar_t itsSharedMap=0;
105 for(i=0;i<AliITSgeomTGeo::kNLayers;i++) {
106 if(fSharedWeight[i]>0) SETBIT(itsSharedMap,i);
109 fESDtrack->SetITSSharedMap(itsSharedMap);
112 // copy the 4 dedx samples
113 Double_t sdedx[4]={0.,0.,0.,0.};
114 for(i=0; i<4; i++) sdedx[i]=fdEdxSample[i];
115 fESDtrack->SetITSdEdxSamples(sdedx);
118 //____________________________________________________________________________
119 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
121 fCheckInvariant(t.fCheckInvariant),
123 fESDtrack(t.fESDtrack)
125 //------------------------------------------------------------------
127 //------------------------------------------------------------------
129 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
130 for (i=0; i<2*AliITSgeomTGeo::GetNLayers(); i++) {
131 fIndex[i]=t.fIndex[i];
132 fModule[i]=t.fModule[i];
134 for (i=0; i<AliITSgeomTGeo::kNLayers; i++) {fSharedWeight[i]=t.fSharedWeight[i];}
137 //_____________________________________________________________________________
138 Int_t AliITStrackV2::Compare(const TObject *o) const {
139 //-----------------------------------------------------------------
140 // This function compares tracks according to the their curvature
141 //-----------------------------------------------------------------
142 AliITStrackV2 *t=(AliITStrackV2*)o;
143 //Double_t co=OneOverPt();
144 //Double_t c =OneOverPt();
145 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
146 Double_t c =GetSigmaY2()*GetSigmaZ2();
148 else if (c<co) return -1;
152 //____________________________________________________________________________
154 AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
156 //------------------------------------------------------------------
157 //This function propagates a track to the minimal distance from the origin
158 //------------------------------------------------------------------
160 if (PropagateToDCA(v,bz,kVeryBig)) {
161 Double_t xOverX0,xTimesRho;
162 xOverX0 = d; xTimesRho = d*x0;
163 if (CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kTRUE;
168 //____________________________________________________________________________
169 Bool_t AliITStrackV2::
170 GetGlobalXYZat(Double_t xloc, Double_t &x, Double_t &y, Double_t &z) const {
171 //------------------------------------------------------------------
172 //This function returns a track position in the global system
173 //------------------------------------------------------------------
175 Bool_t rc=GetXYZAt(xloc, GetBz(), r);
176 x=r[0]; y=r[1]; z=r[2];
180 //_____________________________________________________________________________
181 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
182 //-----------------------------------------------------------------
183 // This function calculates a predicted chi2 increment.
184 //-----------------------------------------------------------------
185 Double_t p[2]={c->GetY(), c->GetZ()};
186 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
187 return AliExternalTrackParam::GetPredictedChi2(p,cov);
190 //____________________________________________________________________________
191 Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
192 //------------------------------------------------------------------
193 //This function propagates a track
194 //------------------------------------------------------------------
196 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
198 //Double_t bz=GetBz();
199 //if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
200 Double_t b[3]; GetBxByBz(b);
201 if (!AliExternalTrackParam::PropagateToBxByBz(xk,b)) return kFALSE;
202 Double_t xOverX0,xTimesRho;
203 xOverX0 = d; xTimesRho = d*x0;
204 if (!CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kFALSE;
206 Double_t x=GetX(), y=GetY(), z=GetZ();
207 if (IsStartedTimeIntegral() && x>oldX) {
208 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
209 AddTimeStep(TMath::Sqrt(l2));
215 //____________________________________________________________________________
216 Bool_t AliITStrackV2::PropagateToTGeo(Double_t xToGo, Int_t nstep, Double_t &xOverX0, Double_t &xTimesRho, Bool_t addTime) {
217 //-------------------------------------------------------------------
218 // Propagates the track to a reference plane x=xToGo in n steps.
219 // These n steps are only used to take into account the curvature.
220 // The material is calculated with TGeo. (L.Gaudichet)
221 //-------------------------------------------------------------------
223 Double_t startx = GetX(), starty = GetY(), startz = GetZ();
224 Double_t sign = (startx<xToGo) ? -1.:1.;
225 Double_t step = (xToGo-startx)/TMath::Abs(nstep);
227 Double_t start[3], end[3], mparam[7];
228 //Double_t bz = GetBz();
229 Double_t b[3]; GetBxByBz(b);
234 for (Int_t i=0; i<nstep; i++) {
236 GetXYZ(start); //starting global position
238 if (!GetXYZAt(x, bz, end)) return kFALSE;
239 //if (!AliExternalTrackParam::PropagateTo(x, bz)) return kFALSE;
240 if (!AliExternalTrackParam::PropagateToBxByBz(x, b)) return kFALSE;
241 AliTracker::MeanMaterialBudget(start, end, mparam);
242 xTimesRho = sign*mparam[4]*mparam[0];
244 if (mparam[1]<900000) {
245 if (!AliExternalTrackParam::CorrectForMeanMaterial(xOverX0,
246 xTimesRho,GetMass())) return kFALSE;
247 } else { // this happens when MeanMaterialBudget cannot cross a boundary
252 if (addTime && IsStartedTimeIntegral() && GetX()>startx) {
253 Double_t l2 = ( (GetX()-startx)*(GetX()-startx) +
254 (GetY()-starty)*(GetY()-starty) +
255 (GetZ()-startz)*(GetZ()-startz) );
256 AddTimeStep(TMath::Sqrt(l2));
262 //____________________________________________________________________________
263 Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
265 //------------------------------------------------------------------
266 //This function updates track parameters
267 //------------------------------------------------------------------
268 Double_t p[2]={c->GetY(), c->GetZ()};
269 Double_t cov[3]={c->GetSigmaY2(), c->GetSigmaYZ(), c->GetSigmaZ2()};
271 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
273 Int_t n=GetNumberOfClusters();
275 if (n>fgkWARN) AliWarning("Wrong invariant !");
279 if (chi2<0) return kTRUE;
281 // fill residuals for ITS+TPC tracks
283 if (fESDtrack->GetStatus()&AliESDtrack::kTPCin) {
284 AliTracker::FillResiduals(this,p,cov,c->GetVolumeId());
289 SetNumberOfClusters(n+1);
290 SetChi2(GetChi2()+chi2);
295 Bool_t AliITStrackV2::Invariant() const {
296 //------------------------------------------------------------------
297 // This function is for debugging purpose only
298 //------------------------------------------------------------------
299 if(!fCheckInvariant) return kTRUE;
301 Int_t n=GetNumberOfClusters();
303 // take into account the misalignment error
304 Float_t maxMisalErrY2=0,maxMisalErrZ2=0;
305 for (Int_t lay=0; lay<AliITSgeomTGeo::kNLayers; lay++) {
306 maxMisalErrY2 = TMath::Max(maxMisalErrY2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorY(lay,GetBz()));
307 maxMisalErrZ2 = TMath::Max(maxMisalErrZ2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorZ(lay,GetBz()));
309 maxMisalErrY2 *= maxMisalErrY2;
310 maxMisalErrZ2 *= maxMisalErrZ2;
311 // this is because when we reset before refitting, we multiply the
313 maxMisalErrY2 *= 10.;
314 maxMisalErrZ2 *= 10.;
316 Double_t sP2=GetParameter()[2];
317 if (TMath::Abs(sP2) >= kAlmost1){
318 if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2);
321 Double_t sC00=GetCovariance()[0];
322 if (sC00<=0 || sC00>(9.+maxMisalErrY2)) {
323 if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00);
326 Double_t sC11=GetCovariance()[2];
327 if (sC11<=0 || sC11>(9.+maxMisalErrZ2)) {
328 if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11);
331 Double_t sC22=GetCovariance()[5];
332 if (sC22<=0 || sC22>1.) {
333 if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22);
336 Double_t sC33=GetCovariance()[9];
337 if (sC33<=0 || sC33>1.) {
338 if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33);
341 Double_t sC44=GetCovariance()[14];
342 if (sC44<=0 /*|| sC44>6e-5*/) {
343 if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44);
350 //____________________________________________________________________________
351 Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
352 //------------------------------------------------------------------
353 //This function propagates a track
354 //------------------------------------------------------------------
355 //Double_t bz=GetBz();
356 //if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
357 Double_t b[3]; GetBxByBz(b);
358 if (!AliExternalTrackParam::PropagateBxByBz(alp,xk,b)) return kFALSE;
361 Int_t n=GetNumberOfClusters();
362 if (n>fgkWARN) AliWarning("Wrong invariant !");
369 Bool_t AliITStrackV2::MeanBudgetToPrimVertex(Double_t xyz[3], Double_t step, Double_t &d) const {
371 //-------------------------------------------------------------------
372 // Get the mean material budget between the actual point and the
373 // primary vertex. (L.Gaudichet)
374 //-------------------------------------------------------------------
376 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
377 Double_t vertexX = xyz[0]*cs + xyz[1]*sn;
379 Int_t nstep = Int_t((GetX()-vertexX)/step);
380 if (nstep<1) nstep = 1;
381 step = (GetX()-vertexX)/nstep;
383 // Double_t mparam[7], densMean=0, radLength=0, length=0;
385 Double_t p1[3], p2[3], x = GetX(), bz = GetBz();
390 for (Int_t i=0; i<nstep; i++) {
392 if (!GetXYZAt(x, bz, p2)) return kFALSE;
393 AliTracker::MeanMaterialBudget(p1, p2, mparam);
394 if (mparam[1]>900000) return kFALSE;
405 Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
406 //------------------------------------------------------------------
407 //This function improves angular track parameters
408 //------------------------------------------------------------------
409 //Store the initail track parameters
412 Double_t alpha = GetAlpha();
413 Double_t par[] = {GetY(),GetZ(),GetSnp(),GetTgl(),GetSigned1Pt()};
433 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
434 Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
435 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
436 Double_t zv = xyz[2]; // local frame
438 Double_t dx = x - xv, dy = par[0] - yv, dz = par[1] - zv;
439 Double_t r2=dx*dx + dy*dy;
440 Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt());
441 Double_t beta2=p2/(p2 + GetMass()*GetMass());
442 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
443 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
444 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
447 Double_t cnv=bz*kB2C;
448 Double_t curv=GetC(bz);
450 Double_t dummy = 4/r2 - curv*curv;
451 if (dummy < 0) return kFALSE;
452 Double_t parp = 0.5*(curv*dx + dy*TMath::Sqrt(dummy));
453 Double_t sigma2p = theta2*(1.-GetSnp())*(1.+GetSnp())*(1. + GetTgl()*GetTgl());
454 Double_t ovSqr2 = 1./TMath::Sqrt(r2);
455 Double_t tfact = ovSqr2*(1.-dy*ovSqr2)*(1.+dy*ovSqr2);
456 sigma2p += cov[0]*tfact*tfact;
457 sigma2p += ers[1]*ers[1]/r2;
458 sigma2p += 0.25*cov[14]*cnv*cnv*dx*dx;
459 Double_t eps2p=sigma2p/(cov[5] + sigma2p);
460 par[0] += cov[3]/(cov[5] + sigma2p)*(parp - GetSnp());
461 par[2] = eps2p*GetSnp() + (1 - eps2p)*parp;
466 Double_t parl=0.5*curv*dz/TMath::ASin(0.5*curv*TMath::Sqrt(r2));
467 Double_t sigma2l=theta2;
468 sigma2l += cov[2]/r2 + cov[0]*dy*dy*dz*dz/(r2*r2*r2);
469 sigma2l += ers[2]*ers[2]/r2;
470 Double_t eps2l = sigma2l/(cov[9] + sigma2l);
471 par[1] += cov[7 ]/(cov[9] + sigma2l)*(parl - par[3]);
472 par[4] += cov[13]/(cov[9] + sigma2l)*(parl - par[3]);
473 par[3] = eps2l*par[3] + (1-eps2l)*parl;
479 Set(x,alpha,par,cov);
481 if (!Invariant()) return kFALSE;
486 void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
487 //-----------------------------------------------------------------
488 // This function calculates dE/dX within the "low" and "up" cuts.
489 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
490 // Updated: F. Prino 8-June-2009
491 //-----------------------------------------------------------------
492 // The cluster order is: SDD-1, SDD-2, SSD-1, SSD-2
496 for (Int_t il=0; il<4; il++) { // count good (>0) dE/dx values
497 if(fdEdxSample[il]>0.){
498 dedx[nc]= fdEdxSample[il];
507 Int_t swap; // sort in ascending order
510 for (Int_t i=0; i<nc-1; i++) {
511 if (dedx[i]<=dedx[i+1]) continue;
520 Double_t nl=low*nc, nu =up*nc;
522 Float_t sumweight =0;
523 for (Int_t i=0; i<nc; i++) {
525 if (i<nl+0.1) weight = TMath::Max(1.-(nl-i),0.);
526 if (i>nu-1) weight = TMath::Max(nu-i,0.);
527 sumamp+= dedx[i]*weight;
530 SetdEdx(sumamp/sumweight);
533 //____________________________________________________________________________
534 Bool_t AliITStrackV2::
535 GetPhiZat(Double_t r, Double_t &phi, Double_t &z) const {
536 //------------------------------------------------------------------
537 // This function returns the global cylindrical (phi,z) of the track
538 // position estimated at the radius r.
539 // The track curvature is neglected.
540 //------------------------------------------------------------------
541 Double_t d=GetD(0.,0.);
542 if (TMath::Abs(d) > r) {
543 if (r>1e-1) return kFALSE;
547 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
548 if (TMath::Abs(d) > rcurr) return kFALSE;
549 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
550 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
553 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
555 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
558 // return a phi in [0,2pi[
559 if (phi<0.) phi+=2.*TMath::Pi();
560 else if (phi>=2.*TMath::Pi()) phi-=2.*TMath::Pi();
561 z=GetZ()+GetTgl()*(TMath::Sqrt((r-d)*(r+d))-TMath::Sqrt((rcurr-d)*(rcurr+d)));
564 //____________________________________________________________________________
565 Bool_t AliITStrackV2::
566 GetLocalXat(Double_t r,Double_t &xloc) const {
567 //------------------------------------------------------------------
568 // This function returns the local x of the track
569 // position estimated at the radius r.
570 // The track curvature is neglected.
571 //------------------------------------------------------------------
572 Double_t d=GetD(0.,0.);
573 if (TMath::Abs(d) > r) {
574 if (r>1e-1) return kFALSE;
578 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
579 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
580 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
583 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
585 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
588 xloc=r*(TMath::Cos(phi)*TMath::Cos(GetAlpha())
589 +TMath::Sin(phi)*TMath::Sin(GetAlpha()));