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 *
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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 "AliTracker.h"
28 #include "AliESDtrack.h"
29 #include "AliITSReconstructor.h"
30 #include "AliITStrackV2.h"
32 const Int_t AliITStrackV2::fgkWARN = 5;
34 ClassImp(AliITStrackV2)
37 //____________________________________________________________________________
38 AliITStrackV2::AliITStrackV2() : AliKalmanTrack(),
42 for(Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) {fIndex[i]=-1; fModule[i]=-1;}
43 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
47 //____________________________________________________________________________
48 AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c) throw (const Char_t *) :
50 fdEdx(t.GetITSsignal()),
53 //------------------------------------------------------------------
54 // Conversion ESD track -> ITS track.
55 // If c==kTRUE, create the ITS track out of the constrained params.
56 //------------------------------------------------------------------
57 const AliExternalTrackParam *par=&t;
59 par=t.GetConstrainedParam();
60 if (!par) throw "AliITStrackV2: conversion failed !\n";
62 Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance());
64 //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
66 SetLabel(t.GetLabel());
68 SetNumberOfClusters(t.GetITSclusters(fIndex));
70 if (t.GetStatus()&AliESDtrack::kTIME) {
72 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
73 SetIntegratedLength(t.GetIntegratedLength());
76 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
79 //____________________________________________________________________________
80 void AliITStrackV2::ResetClusters() {
81 //------------------------------------------------------------------
82 // Reset the array of attached clusters.
83 //------------------------------------------------------------------
84 for (Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) fIndex[i]=-1;
86 SetNumberOfClusters(0);
89 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
90 fESDtrack->UpdateTrackParams(this,flags);
91 // copy the module indices
92 for(Int_t i=0;i<12;i++) {
93 // printf(" %d\n",GetModuleIndex(i));
94 fESDtrack->SetITSModuleIndex(i,GetModuleIndex(i));
98 //____________________________________________________________________________
99 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
102 fESDtrack(t.fESDtrack)
104 //------------------------------------------------------------------
106 //------------------------------------------------------------------
108 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
109 for (i=0; i<2*AliITSgeomTGeo::GetNLayers(); i++) {
110 fIndex[i]=t.fIndex[i];
111 fModule[i]=t.fModule[i];
115 //_____________________________________________________________________________
116 Int_t AliITStrackV2::Compare(const TObject *o) const {
117 //-----------------------------------------------------------------
118 // This function compares tracks according to the their curvature
119 //-----------------------------------------------------------------
120 AliITStrackV2 *t=(AliITStrackV2*)o;
121 //Double_t co=OneOverPt();
122 //Double_t c =OneOverPt();
123 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
124 Double_t c =GetSigmaY2()*GetSigmaZ2();
126 else if (c<co) return -1;
130 //____________________________________________________________________________
132 AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
134 //------------------------------------------------------------------
135 //This function propagates a track to the minimal distance from the origin
136 //------------------------------------------------------------------
138 if (PropagateToDCA(v,bz,kVeryBig)) {
139 Double_t xOverX0,xTimesRho;
140 xOverX0 = d; xTimesRho = d*x0;
141 if (CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kTRUE;
146 //____________________________________________________________________________
147 Bool_t AliITStrackV2::
148 GetGlobalXYZat(Double_t xloc, Double_t &x, Double_t &y, Double_t &z) const {
149 //------------------------------------------------------------------
150 //This function returns a track position in the global system
151 //------------------------------------------------------------------
153 Bool_t rc=GetXYZAt(xloc, AliTracker::GetBz(), r);
154 x=r[0]; y=r[1]; z=r[2];
158 //_____________________________________________________________________________
159 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
160 //-----------------------------------------------------------------
161 // This function calculates a predicted chi2 increment.
162 //-----------------------------------------------------------------
163 Double_t p[2]={c->GetY(), c->GetZ()};
164 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
165 return AliExternalTrackParam::GetPredictedChi2(p,cov);
168 //____________________________________________________________________________
169 Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
170 //------------------------------------------------------------------
171 //This function propagates a track
172 //------------------------------------------------------------------
174 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
177 if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
178 Double_t xOverX0,xTimesRho;
179 xOverX0 = d; xTimesRho = d*x0;
180 if (!CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kFALSE;
182 Double_t x=GetX(), y=GetY(), z=GetZ();
183 if (IsStartedTimeIntegral() && x>oldX) {
184 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
185 AddTimeStep(TMath::Sqrt(l2));
191 //____________________________________________________________________________
192 Bool_t AliITStrackV2::PropagateToTGeo(Double_t xToGo, Int_t nstep, Double_t &xOverX0, Double_t &xTimesRho) {
193 //-------------------------------------------------------------------
194 // Propagates the track to a reference plane x=xToGo in n steps.
195 // These n steps are only used to take into account the curvature.
196 // The material is calculated with TGeo. (L.Gaudichet)
197 //-------------------------------------------------------------------
199 Double_t startx = GetX(), starty = GetY(), startz = GetZ();
200 Double_t sign = (startx<xToGo) ? -1.:1.;
201 Double_t step = (xToGo-startx)/TMath::Abs(nstep);
203 Double_t start[3], end[3], mparam[7], bz = GetBz();
206 for (Int_t i=0; i<nstep; i++) {
208 GetXYZ(start); //starting global position
210 if (!GetXYZAt(x, bz, end)) return kFALSE;
211 if (!AliExternalTrackParam::PropagateTo(x, bz)) return kFALSE;
212 AliTracker::MeanMaterialBudget(start, end, mparam);
213 if (mparam[1]<900000) {
214 xTimesRho = sign*mparam[4]*mparam[0];
216 if (!AliExternalTrackParam::CorrectForMeanMaterial(xOverX0,
217 xTimesRho,GetMass())) return kFALSE;
221 if (IsStartedTimeIntegral() && GetX()>startx) {
222 Double_t l2 = ( (GetX()-startx)*(GetX()-startx) +
223 (GetY()-starty)*(GetY()-starty) +
224 (GetZ()-startz)*(GetZ()-startz) );
225 AddTimeStep(TMath::Sqrt(l2));
231 //____________________________________________________________________________
232 Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
234 //------------------------------------------------------------------
235 //This function updates track parameters
236 //------------------------------------------------------------------
237 Double_t p[2]={c->GetY(), c->GetZ()};
238 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
240 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
242 Int_t n=GetNumberOfClusters();
244 if (n>fgkWARN) AliWarning("Wrong invariant !");
248 if (chi2<0) return kTRUE;
250 AliTracker::FillResiduals(this,p,cov,c->GetVolumeId());
253 SetNumberOfClusters(n+1);
254 SetChi2(GetChi2()+chi2);
259 Bool_t AliITStrackV2::Invariant() const {
260 //------------------------------------------------------------------
261 // This function is for debugging purpose only
262 //------------------------------------------------------------------
263 Int_t n=GetNumberOfClusters();
265 // take into account the misalignment error
266 Float_t maxMisalErrY2=0,maxMisalErrZ2=0;
267 for (Int_t lay=0; lay<AliITSgeomTGeo::kNLayers; lay++) {
268 maxMisalErrY2 = TMath::Max(maxMisalErrY2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorY(lay));
269 maxMisalErrZ2 = TMath::Max(maxMisalErrZ2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorZ(lay));
271 maxMisalErrY2 *= maxMisalErrY2;
272 maxMisalErrZ2 *= maxMisalErrZ2;
273 // this is because when we reset before refitting, we multiply the
275 maxMisalErrY2 *= 10.;
276 maxMisalErrZ2 *= 10.;
278 Double_t sP2=GetParameter()[2];
279 if (TMath::Abs(sP2) >= kAlmost1){
280 if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2);
283 Double_t sC00=GetCovariance()[0];
284 if (sC00<=0 || sC00>(9.+maxMisalErrY2)) {
285 if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00);
288 Double_t sC11=GetCovariance()[2];
289 if (sC11<=0 || sC11>(9.+maxMisalErrZ2)) {
290 if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11);
293 Double_t sC22=GetCovariance()[5];
294 if (sC22<=0 || sC22>1.) {
295 if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22);
298 Double_t sC33=GetCovariance()[9];
299 if (sC33<=0 || sC33>1.) {
300 if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33);
303 Double_t sC44=GetCovariance()[14];
304 if (sC44<=0 /*|| sC44>6e-5*/) {
305 if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44);
312 //____________________________________________________________________________
313 Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
314 //------------------------------------------------------------------
315 //This function propagates a track
316 //------------------------------------------------------------------
318 if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
321 Int_t n=GetNumberOfClusters();
322 if (n>fgkWARN) AliWarning("Wrong invariant !");
329 Bool_t AliITStrackV2::MeanBudgetToPrimVertex(Double_t xyz[3], Double_t step, Double_t &d) const {
331 //-------------------------------------------------------------------
332 // Get the mean material budget between the actual point and the
333 // primary vertex. (L.Gaudichet)
334 //-------------------------------------------------------------------
336 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
337 Double_t vertexX = xyz[0]*cs + xyz[1]*sn;
339 Int_t nstep = Int_t((GetX()-vertexX)/step);
340 if (nstep<1) nstep = 1;
341 step = (GetX()-vertexX)/nstep;
343 // Double_t mparam[7], densMean=0, radLength=0, length=0;
345 Double_t p1[3], p2[3], x = GetX(), bz = GetBz();
350 for (Int_t i=0; i<nstep; i++) {
352 if (!GetXYZAt(x, bz, p2)) return kFALSE;
353 AliTracker::MeanMaterialBudget(p1, p2, mparam);
354 if (mparam[1]>900000) return kFALSE;
365 Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
366 //------------------------------------------------------------------
367 //This function improves angular track parameters
368 //------------------------------------------------------------------
369 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
370 //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
371 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
372 Double_t zv = xyz[2]; // local frame
374 Double_t dy = Par(0) - yv, dz = Par(1) - zv;
375 Double_t r2=GetX()*GetX() + dy*dy;
376 Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt());
377 Double_t beta2=p2/(p2 + GetMass()*GetMass());
378 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
379 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
380 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
382 Double_t cnv=GetBz()*kB2C;
384 Double_t dummy = 4/r2 - GetC()*GetC();
385 if (dummy < 0) return kFALSE;
386 Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy));
387 Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
388 sigma2p += Cov(0)/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
389 sigma2p += ers[1]*ers[1]/r2;
390 sigma2p += 0.25*Cov(14)*cnv*cnv*GetX()*GetX();
391 Double_t eps2p=sigma2p/(Cov(5) + sigma2p);
392 Par(0) += Cov(3)/(Cov(5) + sigma2p)*(parp - GetSnp());
393 Par(2) = eps2p*GetSnp() + (1 - eps2p)*parp;
398 Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2));
399 Double_t sigma2l=theta2;
400 sigma2l += Cov(2)/r2 + Cov(0)*dy*dy*dz*dz/(r2*r2*r2);
401 sigma2l += ers[2]*ers[2]/r2;
402 Double_t eps2l = sigma2l/(Cov(9) + sigma2l);
403 Par(1) += Cov(7 )/(Cov(9) + sigma2l)*(parl - Par(3));
404 Par(4) += Cov(13)/(Cov(9) + sigma2l)*(parl - Par(3));
405 Par(3) = eps2l*Par(3) + (1-eps2l)*parl;
410 if (!Invariant()) return kFALSE;
415 void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
416 //-----------------------------------------------------------------
417 // This function calculates dE/dX within the "low" and "up" cuts.
418 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
419 //-----------------------------------------------------------------
420 // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1
424 for (i=0; i<GetNumberOfClusters(); i++) {
425 Int_t idx=GetClusterIndex(i);
426 idx=(idx&0xf0000000)>>28;
427 if (idx>1) nc++; // Take only SSD and SDD
430 Int_t swap;//stupid sorting
433 for (i=0; i<nc-1; i++) {
434 if (fdEdxSample[i]<=fdEdxSample[i+1]) continue;
435 Float_t tmp=fdEdxSample[i];
436 fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp;
441 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX
442 // values from four ones choose
445 for (i=nl; i<nu; i++) dedx += fdEdxSample[i];
446 if (nu-nl>0) dedx /= (nu-nl);
451 Double_t AliITStrackV2::GetBz() const {
453 // returns Bz component of the magnetic field (kG)
455 if (AliTracker::UniformField()) return AliTracker::GetBz();
456 Double_t r[3]; GetXYZ(r);
457 return AliTracker::GetBz(r);
460 //____________________________________________________________________________
461 Bool_t AliITStrackV2::
462 GetPhiZat(Double_t r, Double_t &phi, Double_t &z) const {
463 //------------------------------------------------------------------
464 // This function returns the global cylindrical (phi,z) of the track
465 // position estimated at the radius r.
466 // The track curvature is neglected.
467 //------------------------------------------------------------------
468 Double_t d=GetD(0.,0.);
469 if (TMath::Abs(d) > r) return kFALSE;
471 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
472 if (TMath::Abs(d) > rcurr) return kFALSE;
473 Double_t phicurr=GetAlpha()+TMath::ASin(GetSnp());
475 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
476 z=GetZ()+GetTgl()*(TMath::Sqrt((r-d)*(r+d))-TMath::Sqrt((rcurr-d)*(rcurr+d)));
479 //____________________________________________________________________________
480 Bool_t AliITStrackV2::
481 GetLocalXat(Double_t r,Double_t &xloc) const {
482 //------------------------------------------------------------------
483 // This function returns the local x of the track
484 // position estimated at the radius r.
485 // The track curvature is neglected.
486 //------------------------------------------------------------------
487 Double_t d=GetD(0.,0.);
488 if (TMath::Abs(d) > r) return kFALSE;
490 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
491 Double_t phicurr=GetAlpha()+TMath::ASin(GetSnp());
492 Double_t phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
494 xloc=r*(TMath::Cos(phi)*TMath::Cos(GetAlpha())
495 +TMath::Sin(phi)*TMath::Sin(GetAlpha()));