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 "AliTracker.h"
28 #include "AliESDtrack.h"
29 #include "AliESDVertex.h"
30 #include "AliITSReconstructor.h"
31 #include "AliITStrackV2.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 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
91 fESDtrack->UpdateTrackParams(this,flags);
92 // copy the module indices
93 for(Int_t i=0;i<12;i++) {
94 // printf(" %d\n",GetModuleIndex(i));
95 fESDtrack->SetITSModuleIndex(i,GetModuleIndex(i));
99 //____________________________________________________________________________
100 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
103 fESDtrack(t.fESDtrack)
105 //------------------------------------------------------------------
107 //------------------------------------------------------------------
109 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
110 for (i=0; i<2*AliITSgeomTGeo::GetNLayers(); i++) {
111 fIndex[i]=t.fIndex[i];
112 fModule[i]=t.fModule[i];
116 //_____________________________________________________________________________
117 Int_t AliITStrackV2::Compare(const TObject *o) const {
118 //-----------------------------------------------------------------
119 // This function compares tracks according to the their curvature
120 //-----------------------------------------------------------------
121 AliITStrackV2 *t=(AliITStrackV2*)o;
122 //Double_t co=OneOverPt();
123 //Double_t c =OneOverPt();
124 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
125 Double_t c =GetSigmaY2()*GetSigmaZ2();
127 else if (c<co) return -1;
131 //____________________________________________________________________________
133 AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
135 //------------------------------------------------------------------
136 //This function propagates a track to the minimal distance from the origin
137 //------------------------------------------------------------------
139 if (PropagateToDCA(v,bz,kVeryBig)) {
140 Double_t xOverX0,xTimesRho;
141 xOverX0 = d; xTimesRho = d*x0;
142 if (CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kTRUE;
147 //____________________________________________________________________________
148 Bool_t AliITStrackV2::
149 GetGlobalXYZat(Double_t xloc, Double_t &x, Double_t &y, Double_t &z) const {
150 //------------------------------------------------------------------
151 //This function returns a track position in the global system
152 //------------------------------------------------------------------
154 Bool_t rc=GetXYZAt(xloc, AliTracker::GetBz(), r);
155 x=r[0]; y=r[1]; z=r[2];
159 //_____________________________________________________________________________
160 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
161 //-----------------------------------------------------------------
162 // This function calculates a predicted chi2 increment.
163 //-----------------------------------------------------------------
164 Double_t p[2]={c->GetY(), c->GetZ()};
165 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
166 return AliExternalTrackParam::GetPredictedChi2(p,cov);
169 //____________________________________________________________________________
170 Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
171 //------------------------------------------------------------------
172 //This function propagates a track
173 //------------------------------------------------------------------
175 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
178 if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
179 Double_t xOverX0,xTimesRho;
180 xOverX0 = d; xTimesRho = d*x0;
181 if (!CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kFALSE;
183 Double_t x=GetX(), y=GetY(), z=GetZ();
184 if (IsStartedTimeIntegral() && x>oldX) {
185 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
186 AddTimeStep(TMath::Sqrt(l2));
192 //____________________________________________________________________________
193 Bool_t AliITStrackV2::PropagateToTGeo(Double_t xToGo, Int_t nstep, Double_t &xOverX0, Double_t &xTimesRho, Bool_t addTime) {
194 //-------------------------------------------------------------------
195 // Propagates the track to a reference plane x=xToGo in n steps.
196 // These n steps are only used to take into account the curvature.
197 // The material is calculated with TGeo. (L.Gaudichet)
198 //-------------------------------------------------------------------
200 Double_t startx = GetX(), starty = GetY(), startz = GetZ();
201 Double_t sign = (startx<xToGo) ? -1.:1.;
202 Double_t step = (xToGo-startx)/TMath::Abs(nstep);
204 Double_t start[3], end[3], mparam[7], bz = GetBz();
207 for (Int_t i=0; i<nstep; i++) {
209 GetXYZ(start); //starting global position
211 if (!GetXYZAt(x, bz, end)) return kFALSE;
212 if (!AliExternalTrackParam::PropagateTo(x, bz)) return kFALSE;
213 AliTracker::MeanMaterialBudget(start, end, mparam);
214 if (mparam[1]<900000) {
215 xTimesRho = sign*mparam[4]*mparam[0];
217 if (!AliExternalTrackParam::CorrectForMeanMaterial(xOverX0,
218 xTimesRho,GetMass())) return kFALSE;
222 if (addTime && IsStartedTimeIntegral() && GetX()>startx) {
223 Double_t l2 = ( (GetX()-startx)*(GetX()-startx) +
224 (GetY()-starty)*(GetY()-starty) +
225 (GetZ()-startz)*(GetZ()-startz) );
226 AddTimeStep(TMath::Sqrt(l2));
232 //____________________________________________________________________________
233 Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
235 //------------------------------------------------------------------
236 //This function updates track parameters
237 //------------------------------------------------------------------
238 Double_t p[2]={c->GetY(), c->GetZ()};
239 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
241 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
243 Int_t n=GetNumberOfClusters();
245 if (n>fgkWARN) AliWarning("Wrong invariant !");
249 if (chi2<0) return kTRUE;
251 AliTracker::FillResiduals(this,p,cov,c->GetVolumeId());
254 SetNumberOfClusters(n+1);
255 SetChi2(GetChi2()+chi2);
260 Bool_t AliITStrackV2::Invariant() const {
261 //------------------------------------------------------------------
262 // This function is for debugging purpose only
263 //------------------------------------------------------------------
264 Int_t n=GetNumberOfClusters();
266 // take into account the misalignment error
267 Float_t maxMisalErrY2=0,maxMisalErrZ2=0;
268 for (Int_t lay=0; lay<AliITSgeomTGeo::kNLayers; lay++) {
269 maxMisalErrY2 = TMath::Max(maxMisalErrY2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorY(lay));
270 maxMisalErrZ2 = TMath::Max(maxMisalErrZ2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorZ(lay));
272 maxMisalErrY2 *= maxMisalErrY2;
273 maxMisalErrZ2 *= maxMisalErrZ2;
274 // this is because when we reset before refitting, we multiply the
276 maxMisalErrY2 *= 10.;
277 maxMisalErrZ2 *= 10.;
279 Double_t sP2=GetParameter()[2];
280 if (TMath::Abs(sP2) >= kAlmost1){
281 if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2);
284 Double_t sC00=GetCovariance()[0];
285 if (sC00<=0 || sC00>(9.+maxMisalErrY2)) {
286 if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00);
289 Double_t sC11=GetCovariance()[2];
290 if (sC11<=0 || sC11>(9.+maxMisalErrZ2)) {
291 if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11);
294 Double_t sC22=GetCovariance()[5];
295 if (sC22<=0 || sC22>1.) {
296 if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22);
299 Double_t sC33=GetCovariance()[9];
300 if (sC33<=0 || sC33>1.) {
301 if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33);
304 Double_t sC44=GetCovariance()[14];
305 if (sC44<=0 /*|| sC44>6e-5*/) {
306 if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44);
313 //____________________________________________________________________________
314 Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
315 //------------------------------------------------------------------
316 //This function propagates a track
317 //------------------------------------------------------------------
319 if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
322 Int_t n=GetNumberOfClusters();
323 if (n>fgkWARN) AliWarning("Wrong invariant !");
330 Bool_t AliITStrackV2::MeanBudgetToPrimVertex(Double_t xyz[3], Double_t step, Double_t &d) const {
332 //-------------------------------------------------------------------
333 // Get the mean material budget between the actual point and the
334 // primary vertex. (L.Gaudichet)
335 //-------------------------------------------------------------------
337 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
338 Double_t vertexX = xyz[0]*cs + xyz[1]*sn;
340 Int_t nstep = Int_t((GetX()-vertexX)/step);
341 if (nstep<1) nstep = 1;
342 step = (GetX()-vertexX)/nstep;
344 // Double_t mparam[7], densMean=0, radLength=0, length=0;
346 Double_t p1[3], p2[3], x = GetX(), bz = GetBz();
351 for (Int_t i=0; i<nstep; i++) {
353 if (!GetXYZAt(x, bz, p2)) return kFALSE;
354 AliTracker::MeanMaterialBudget(p1, p2, mparam);
355 if (mparam[1]>900000) return kFALSE;
366 Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
367 //------------------------------------------------------------------
368 //This function improves angular track parameters
369 //------------------------------------------------------------------
370 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
371 //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
372 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
373 Double_t zv = xyz[2]; // local frame
375 Double_t dy = Par(0) - yv, dz = Par(1) - zv;
376 Double_t r2=GetX()*GetX() + dy*dy;
377 Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt());
378 Double_t beta2=p2/(p2 + GetMass()*GetMass());
379 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
380 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
381 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
383 Double_t cnv=GetBz()*kB2C;
385 Double_t dummy = 4/r2 - GetC()*GetC();
386 if (dummy < 0) return kFALSE;
387 Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy));
388 Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
389 sigma2p += Cov(0)/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
390 sigma2p += ers[1]*ers[1]/r2;
391 sigma2p += 0.25*Cov(14)*cnv*cnv*GetX()*GetX();
392 Double_t eps2p=sigma2p/(Cov(5) + sigma2p);
393 Par(0) += Cov(3)/(Cov(5) + sigma2p)*(parp - GetSnp());
394 Par(2) = eps2p*GetSnp() + (1 - eps2p)*parp;
399 Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2));
400 Double_t sigma2l=theta2;
401 sigma2l += Cov(2)/r2 + Cov(0)*dy*dy*dz*dz/(r2*r2*r2);
402 sigma2l += ers[2]*ers[2]/r2;
403 Double_t eps2l = sigma2l/(Cov(9) + sigma2l);
404 Par(1) += Cov(7 )/(Cov(9) + sigma2l)*(parl - Par(3));
405 Par(4) += Cov(13)/(Cov(9) + sigma2l)*(parl - Par(3));
406 Par(3) = eps2l*Par(3) + (1-eps2l)*parl;
411 if (!Invariant()) return kFALSE;
416 void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
417 //-----------------------------------------------------------------
418 // This function calculates dE/dX within the "low" and "up" cuts.
419 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
420 //-----------------------------------------------------------------
421 // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1
425 for (i=0; i<GetNumberOfClusters(); i++) {
426 Int_t idx=GetClusterIndex(i);
427 idx=(idx&0xf0000000)>>28;
428 if (idx>1) nc++; // Take only SSD and SDD
431 Int_t swap;//stupid sorting
434 for (i=0; i<nc-1; i++) {
435 if (fdEdxSample[i]<=fdEdxSample[i+1]) continue;
436 Float_t tmp=fdEdxSample[i];
437 fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp;
442 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX
443 // values from four ones choose
446 for (i=nl; i<nu; i++) dedx += fdEdxSample[i];
447 if (nu-nl>0) dedx /= (nu-nl);
452 Double_t AliITStrackV2::GetBz() const {
454 // returns Bz component of the magnetic field (kG)
456 if (AliTracker::UniformField()) return AliTracker::GetBz();
457 Double_t r[3]; GetXYZ(r);
458 return AliTracker::GetBz(r);
461 //____________________________________________________________________________
462 Bool_t AliITStrackV2::
463 GetPhiZat(Double_t r, Double_t &phi, Double_t &z) const {
464 //------------------------------------------------------------------
465 // This function returns the global cylindrical (phi,z) of the track
466 // position estimated at the radius r.
467 // The track curvature is neglected.
468 //------------------------------------------------------------------
469 Double_t d=GetD(0.,0.);
470 if (TMath::Abs(d) > r) return kFALSE;
472 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
473 if (TMath::Abs(d) > rcurr) return kFALSE;
474 Double_t phicurr=GetAlpha()+TMath::ASin(GetSnp());
476 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
477 z=GetZ()+GetTgl()*(TMath::Sqrt((r-d)*(r+d))-TMath::Sqrt((rcurr-d)*(rcurr+d)));
480 //____________________________________________________________________________
481 Bool_t AliITStrackV2::
482 GetLocalXat(Double_t r,Double_t &xloc) const {
483 //------------------------------------------------------------------
484 // This function returns the local x of the track
485 // position estimated at the radius r.
486 // The track curvature is neglected.
487 //------------------------------------------------------------------
488 Double_t d=GetD(0.,0.);
489 if (TMath::Abs(d) > r) return kFALSE;
491 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
492 Double_t phicurr=GetAlpha()+TMath::ASin(GetSnp());
493 Double_t phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
495 xloc=r*(TMath::Cos(phi)*TMath::Cos(GetAlpha())
496 +TMath::Sin(phi)*TMath::Sin(GetAlpha()));