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 *
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12 * about the suitability of this software for any purpose. It is *
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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 "AliESDtrack.h"
28 #include "AliESDVertex.h"
29 #include "AliITSReconstructor.h"
30 #include "AliITStrackV2.h"
31 #include "AliTracker.h"
33 const Int_t AliITStrackV2::fgkWARN = 5;
35 ClassImp(AliITStrackV2)
38 //____________________________________________________________________________
39 AliITStrackV2::AliITStrackV2() : AliKalmanTrack(),
43 for(Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) {fIndex[i]=-1; fModule[i]=-1;}
44 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
48 //____________________________________________________________________________
49 AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c) throw (const Char_t *) :
51 fdEdx(t.GetITSsignal()),
54 //------------------------------------------------------------------
55 // Conversion ESD track -> ITS track.
56 // If c==kTRUE, create the ITS track out of the constrained params.
57 //------------------------------------------------------------------
58 const AliExternalTrackParam *par=&t;
60 par=t.GetConstrainedParam();
61 if (!par) throw "AliITStrackV2: conversion failed !\n";
63 Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance());
65 //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
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<4; i++) fdEdxSample[i]=0;
80 //____________________________________________________________________________
81 void AliITStrackV2::ResetClusters() {
82 //------------------------------------------------------------------
83 // Reset the array of attached clusters.
84 //------------------------------------------------------------------
85 for (Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) fIndex[i]=-1;
87 SetNumberOfClusters(0);
90 //____________________________________________________________________________
91 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
92 // Update track params
93 fESDtrack->UpdateTrackParams(this,flags);
94 // copy the module indices
95 for(Int_t i=0;i<12;i++) {
96 // printf(" %d\n",GetModuleIndex(i));
97 fESDtrack->SetITSModuleIndex(i,GetModuleIndex(i));
99 // copy the 4 dedx samples
100 Double_t sdedx[4]={0.,0.,0.,0.};
101 for(Int_t i=0; i<4; i++) sdedx[i]=fdEdxSample[i];
102 fESDtrack->SetITSdEdxSamples(sdedx);
105 //____________________________________________________________________________
106 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
109 fESDtrack(t.fESDtrack)
111 //------------------------------------------------------------------
113 //------------------------------------------------------------------
115 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
116 for (i=0; i<2*AliITSgeomTGeo::GetNLayers(); i++) {
117 fIndex[i]=t.fIndex[i];
118 fModule[i]=t.fModule[i];
122 //_____________________________________________________________________________
123 Int_t AliITStrackV2::Compare(const TObject *o) const {
124 //-----------------------------------------------------------------
125 // This function compares tracks according to the their curvature
126 //-----------------------------------------------------------------
127 AliITStrackV2 *t=(AliITStrackV2*)o;
128 //Double_t co=OneOverPt();
129 //Double_t c =OneOverPt();
130 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
131 Double_t c =GetSigmaY2()*GetSigmaZ2();
133 else if (c<co) return -1;
137 //____________________________________________________________________________
139 AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
141 //------------------------------------------------------------------
142 //This function propagates a track to the minimal distance from the origin
143 //------------------------------------------------------------------
145 if (PropagateToDCA(v,bz,kVeryBig)) {
146 Double_t xOverX0,xTimesRho;
147 xOverX0 = d; xTimesRho = d*x0;
148 if (CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kTRUE;
153 //____________________________________________________________________________
154 Bool_t AliITStrackV2::
155 GetGlobalXYZat(Double_t xloc, Double_t &x, Double_t &y, Double_t &z) const {
156 //------------------------------------------------------------------
157 //This function returns a track position in the global system
158 //------------------------------------------------------------------
160 Bool_t rc=GetXYZAt(xloc, GetBz(), r);
161 x=r[0]; y=r[1]; z=r[2];
165 //_____________________________________________________________________________
166 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
167 //-----------------------------------------------------------------
168 // This function calculates a predicted chi2 increment.
169 //-----------------------------------------------------------------
170 Double_t p[2]={c->GetY(), c->GetZ()};
171 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
172 return AliExternalTrackParam::GetPredictedChi2(p,cov);
175 //____________________________________________________________________________
176 Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
177 //------------------------------------------------------------------
178 //This function propagates a track
179 //------------------------------------------------------------------
181 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
184 if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
185 Double_t xOverX0,xTimesRho;
186 xOverX0 = d; xTimesRho = d*x0;
187 if (!CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kFALSE;
189 Double_t x=GetX(), y=GetY(), z=GetZ();
190 if (IsStartedTimeIntegral() && x>oldX) {
191 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
192 AddTimeStep(TMath::Sqrt(l2));
198 //____________________________________________________________________________
199 Bool_t AliITStrackV2::PropagateToTGeo(Double_t xToGo, Int_t nstep, Double_t &xOverX0, Double_t &xTimesRho, Bool_t addTime) {
200 //-------------------------------------------------------------------
201 // Propagates the track to a reference plane x=xToGo in n steps.
202 // These n steps are only used to take into account the curvature.
203 // The material is calculated with TGeo. (L.Gaudichet)
204 //-------------------------------------------------------------------
206 Double_t startx = GetX(), starty = GetY(), startz = GetZ();
207 Double_t sign = (startx<xToGo) ? -1.:1.;
208 Double_t step = (xToGo-startx)/TMath::Abs(nstep);
210 Double_t start[3], end[3], mparam[7], bz = GetBz();
213 for (Int_t i=0; i<nstep; i++) {
215 GetXYZ(start); //starting global position
217 if (!GetXYZAt(x, bz, end)) return kFALSE;
218 if (!AliExternalTrackParam::PropagateTo(x, bz)) return kFALSE;
219 AliTracker::MeanMaterialBudget(start, end, mparam);
220 xTimesRho = sign*mparam[4]*mparam[0];
222 if (mparam[1]<900000) {
223 if (!AliExternalTrackParam::CorrectForMeanMaterial(xOverX0,
224 xTimesRho,GetMass())) return kFALSE;
225 } else { // this happens when MeanMaterialBudget cannot cross a boundary
230 if (addTime && IsStartedTimeIntegral() && GetX()>startx) {
231 Double_t l2 = ( (GetX()-startx)*(GetX()-startx) +
232 (GetY()-starty)*(GetY()-starty) +
233 (GetZ()-startz)*(GetZ()-startz) );
234 AddTimeStep(TMath::Sqrt(l2));
240 //____________________________________________________________________________
241 Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
243 //------------------------------------------------------------------
244 //This function updates track parameters
245 //------------------------------------------------------------------
246 Double_t p[2]={c->GetY(), c->GetZ()};
247 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
249 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
251 Int_t n=GetNumberOfClusters();
253 if (n>fgkWARN) AliWarning("Wrong invariant !");
257 if (chi2<0) return kTRUE;
259 // fill residuals for ITS+TPC tracks
261 if (fESDtrack->GetStatus()&AliESDtrack::kTPCin) {
262 AliTracker::FillResiduals(this,p,cov,c->GetVolumeId());
267 SetNumberOfClusters(n+1);
268 SetChi2(GetChi2()+chi2);
273 Bool_t AliITStrackV2::Invariant() const {
274 //------------------------------------------------------------------
275 // This function is for debugging purpose only
276 //------------------------------------------------------------------
277 Int_t n=GetNumberOfClusters();
279 // take into account the misalignment error
280 Float_t maxMisalErrY2=0,maxMisalErrZ2=0;
281 for (Int_t lay=0; lay<AliITSgeomTGeo::kNLayers; lay++) {
282 maxMisalErrY2 = TMath::Max(maxMisalErrY2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorY(lay));
283 maxMisalErrZ2 = TMath::Max(maxMisalErrZ2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorZ(lay));
285 maxMisalErrY2 *= maxMisalErrY2;
286 maxMisalErrZ2 *= maxMisalErrZ2;
287 // this is because when we reset before refitting, we multiply the
289 maxMisalErrY2 *= 10.;
290 maxMisalErrZ2 *= 10.;
292 Double_t sP2=GetParameter()[2];
293 if (TMath::Abs(sP2) >= kAlmost1){
294 if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2);
297 Double_t sC00=GetCovariance()[0];
298 if (sC00<=0 || sC00>(9.+maxMisalErrY2)) {
299 if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00);
302 Double_t sC11=GetCovariance()[2];
303 if (sC11<=0 || sC11>(9.+maxMisalErrZ2)) {
304 if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11);
307 Double_t sC22=GetCovariance()[5];
308 if (sC22<=0 || sC22>1.) {
309 if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22);
312 Double_t sC33=GetCovariance()[9];
313 if (sC33<=0 || sC33>1.) {
314 if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33);
317 Double_t sC44=GetCovariance()[14];
318 if (sC44<=0 /*|| sC44>6e-5*/) {
319 if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44);
326 //____________________________________________________________________________
327 Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
328 //------------------------------------------------------------------
329 //This function propagates a track
330 //------------------------------------------------------------------
332 if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
335 Int_t n=GetNumberOfClusters();
336 if (n>fgkWARN) AliWarning("Wrong invariant !");
343 Bool_t AliITStrackV2::MeanBudgetToPrimVertex(Double_t xyz[3], Double_t step, Double_t &d) const {
345 //-------------------------------------------------------------------
346 // Get the mean material budget between the actual point and the
347 // primary vertex. (L.Gaudichet)
348 //-------------------------------------------------------------------
350 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
351 Double_t vertexX = xyz[0]*cs + xyz[1]*sn;
353 Int_t nstep = Int_t((GetX()-vertexX)/step);
354 if (nstep<1) nstep = 1;
355 step = (GetX()-vertexX)/nstep;
357 // Double_t mparam[7], densMean=0, radLength=0, length=0;
359 Double_t p1[3], p2[3], x = GetX(), bz = GetBz();
364 for (Int_t i=0; i<nstep; i++) {
366 if (!GetXYZAt(x, bz, p2)) return kFALSE;
367 AliTracker::MeanMaterialBudget(p1, p2, mparam);
368 if (mparam[1]>900000) return kFALSE;
379 Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
380 //------------------------------------------------------------------
381 //This function improves angular track parameters
382 //------------------------------------------------------------------
383 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
384 //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
385 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
386 Double_t zv = xyz[2]; // local frame
388 Double_t dy = Par(0) - yv, dz = Par(1) - zv;
389 Double_t r2=GetX()*GetX() + dy*dy;
390 Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt());
391 Double_t beta2=p2/(p2 + GetMass()*GetMass());
392 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
393 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
394 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
396 Double_t cnv=GetBz()*kB2C;
398 Double_t dummy = 4/r2 - GetC()*GetC();
399 if (dummy < 0) return kFALSE;
400 Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy));
401 Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
402 sigma2p += Cov(0)/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
403 sigma2p += ers[1]*ers[1]/r2;
404 sigma2p += 0.25*Cov(14)*cnv*cnv*GetX()*GetX();
405 Double_t eps2p=sigma2p/(Cov(5) + sigma2p);
406 Par(0) += Cov(3)/(Cov(5) + sigma2p)*(parp - GetSnp());
407 Par(2) = eps2p*GetSnp() + (1 - eps2p)*parp;
412 Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2));
413 Double_t sigma2l=theta2;
414 sigma2l += Cov(2)/r2 + Cov(0)*dy*dy*dz*dz/(r2*r2*r2);
415 sigma2l += ers[2]*ers[2]/r2;
416 Double_t eps2l = sigma2l/(Cov(9) + sigma2l);
417 Par(1) += Cov(7 )/(Cov(9) + sigma2l)*(parl - Par(3));
418 Par(4) += Cov(13)/(Cov(9) + sigma2l)*(parl - Par(3));
419 Par(3) = eps2l*Par(3) + (1-eps2l)*parl;
424 if (!Invariant()) return kFALSE;
429 void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
430 //-----------------------------------------------------------------
431 // This function calculates dE/dX within the "low" and "up" cuts.
432 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
433 // Updated: F. Prino 8-June-2009
434 //-----------------------------------------------------------------
435 // The cluster order is: SDD-1, SDD-2, SSD-1, SSD-2
439 for (Int_t il=0; il<4; il++) { // count good (>0) dE/dx values
440 if(fdEdxSample[il]>0.){
441 dedx[nc]= fdEdxSample[il];
450 Int_t swap; // sort in ascending order
453 for (Int_t i=0; i<nc-1; i++) {
454 if (dedx[i]<=dedx[i+1]) continue;
463 Double_t nl=low*nc, nu =up*nc;
465 Float_t sumweight =0;
466 for (Int_t i=0; i<nc; i++) {
468 if (i<nl+0.1) weight = TMath::Max(1.-(nl-i),0.);
469 if (i>nu-1) weight = TMath::Max(nu-i,0.);
470 sumamp+= dedx[i]*weight;
473 SetdEdx(sumamp/sumweight);
476 //____________________________________________________________________________
477 Bool_t AliITStrackV2::
478 GetPhiZat(Double_t r, Double_t &phi, Double_t &z) const {
479 //------------------------------------------------------------------
480 // This function returns the global cylindrical (phi,z) of the track
481 // position estimated at the radius r.
482 // The track curvature is neglected.
483 //------------------------------------------------------------------
484 Double_t d=GetD(0.,0.);
485 if (TMath::Abs(d) > r) {
486 if (r>1e-1) return kFALSE;
490 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
491 if (TMath::Abs(d) > rcurr) return kFALSE;
492 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
493 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
496 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
498 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
501 // return a phi in [0,2pi[
502 if (phi<0.) phi+=2.*TMath::Pi();
503 else if (phi>=2.*TMath::Pi()) phi-=2.*TMath::Pi();
504 z=GetZ()+GetTgl()*(TMath::Sqrt((r-d)*(r+d))-TMath::Sqrt((rcurr-d)*(rcurr+d)));
507 //____________________________________________________________________________
508 Bool_t AliITStrackV2::
509 GetLocalXat(Double_t r,Double_t &xloc) const {
510 //------------------------------------------------------------------
511 // This function returns the local x of the track
512 // position estimated at the radius r.
513 // The track curvature is neglected.
514 //------------------------------------------------------------------
515 Double_t d=GetD(0.,0.);
516 if (TMath::Abs(d) > r) {
517 if (r>1e-1) return kFALSE;
521 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
522 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
523 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
526 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
528 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
531 xloc=r*(TMath::Cos(phi)*TMath::Cos(GetAlpha())
532 +TMath::Sin(phi)*TMath::Sin(GetAlpha()));