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 *
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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 "AliITStrackV2.h"
31 const Int_t AliITStrackV2::fgkWARN = 5;
33 ClassImp(AliITStrackV2)
36 //____________________________________________________________________________
37 AliITStrackV2::AliITStrackV2() : AliKalmanTrack(),
41 for(Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) {fIndex[i]=-1; fModule[i]=-1;}
42 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
46 //____________________________________________________________________________
47 AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c) throw (const Char_t *) :
49 fdEdx(t.GetITSsignal()),
52 //------------------------------------------------------------------
53 // Conversion ESD track -> ITS track.
54 // If c==kTRUE, create the ITS track out of the constrained params.
55 //------------------------------------------------------------------
56 const AliExternalTrackParam *par=&t;
58 par=t.GetConstrainedParam();
59 if (!par) throw "AliITStrackV2: conversion failed !\n";
61 Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance());
63 //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
65 SetLabel(t.GetLabel());
67 SetNumberOfClusters(t.GetITSclusters(fIndex));
69 if (t.GetStatus()&AliESDtrack::kTIME) {
71 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
72 SetIntegratedLength(t.GetIntegratedLength());
75 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
78 //____________________________________________________________________________
79 void AliITStrackV2::ResetClusters() {
80 //------------------------------------------------------------------
81 // Reset the array of attached clusters.
82 //------------------------------------------------------------------
83 for (Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) fIndex[i]=-1;
85 SetNumberOfClusters(0);
88 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
89 fESDtrack->UpdateTrackParams(this,flags);
90 // copy the module indices
91 for(Int_t i=0;i<12;i++) {
92 // printf(" %d\n",GetModuleIndex(i));
93 fESDtrack->SetITSModuleIndex(i,GetModuleIndex(i));
97 //____________________________________________________________________________
98 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
101 fESDtrack(t.fESDtrack)
103 //------------------------------------------------------------------
105 //------------------------------------------------------------------
107 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
108 for (i=0; i<2*AliITSgeomTGeo::GetNLayers(); i++) {
109 fIndex[i]=t.fIndex[i];
110 fModule[i]=t.fModule[i];
114 //_____________________________________________________________________________
115 Int_t AliITStrackV2::Compare(const TObject *o) const {
116 //-----------------------------------------------------------------
117 // This function compares tracks according to the their curvature
118 //-----------------------------------------------------------------
119 AliITStrackV2 *t=(AliITStrackV2*)o;
120 //Double_t co=OneOverPt();
121 //Double_t c =OneOverPt();
122 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
123 Double_t c =GetSigmaY2()*GetSigmaZ2();
125 else if (c<co) return -1;
129 //____________________________________________________________________________
131 AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
133 //------------------------------------------------------------------
134 //This function propagates a track to the minimal distance from the origin
135 //------------------------------------------------------------------
137 if (PropagateToDCA(v,bz,kVeryBig)) {
138 Double_t xOverX0,xTimesRho;
139 xOverX0 = d; xTimesRho = d*x0;
140 if (CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kTRUE;
145 //____________________________________________________________________________
146 Bool_t AliITStrackV2::
147 GetGlobalXYZat(Double_t xloc, Double_t &x, Double_t &y, Double_t &z) const {
148 //------------------------------------------------------------------
149 //This function returns a track position in the global system
150 //------------------------------------------------------------------
152 Bool_t rc=GetXYZAt(xloc, AliTracker::GetBz(), r);
153 x=r[0]; y=r[1]; z=r[2];
157 //_____________________________________________________________________________
158 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
159 //-----------------------------------------------------------------
160 // This function calculates a predicted chi2 increment.
161 //-----------------------------------------------------------------
162 Double_t p[2]={c->GetY(), c->GetZ()};
163 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
164 return AliExternalTrackParam::GetPredictedChi2(p,cov);
167 //____________________________________________________________________________
168 Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
169 //------------------------------------------------------------------
170 //This function propagates a track
171 //------------------------------------------------------------------
173 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
176 if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
177 Double_t xOverX0,xTimesRho;
178 xOverX0 = d; xTimesRho = d*x0;
179 if (!CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kFALSE;
181 Double_t x=GetX(), y=GetY(), z=GetZ();
182 if (IsStartedTimeIntegral() && x>oldX) {
183 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
184 AddTimeStep(TMath::Sqrt(l2));
190 //____________________________________________________________________________
191 Bool_t AliITStrackV2::PropagateToTGeo(Double_t xToGo, Int_t nstep, Double_t &xOverX0, Double_t &xTimesRho) {
192 //-------------------------------------------------------------------
193 // Propagates the track to a reference plane x=xToGo in n steps.
194 // These n steps are only used to take into account the curvature.
195 // The material is calculated with TGeo. (L.Gaudichet)
196 //-------------------------------------------------------------------
198 Double_t startx = GetX(), starty = GetY(), startz = GetZ();
199 Double_t sign = (startx<xToGo) ? -1.:1.;
200 Double_t step = (xToGo-startx)/TMath::Abs(nstep);
202 Double_t start[3], end[3], mparam[7], bz = GetBz();
205 for (Int_t i=0; i<nstep; i++) {
207 GetXYZ(start); //starting global position
209 if (!GetXYZAt(x, bz, end)) return kFALSE;
210 if (!AliExternalTrackParam::PropagateTo(x, bz)) return kFALSE;
211 AliTracker::MeanMaterialBudget(start, end, mparam);
212 if (mparam[1]<900000) {
213 xTimesRho = sign*mparam[4]*mparam[0];
215 if (!AliExternalTrackParam::CorrectForMeanMaterial(xOverX0,
216 xTimesRho,GetMass())) return kFALSE;
220 if (IsStartedTimeIntegral() && GetX()>startx) {
221 Double_t l2 = ( (GetX()-startx)*(GetX()-startx) +
222 (GetY()-starty)*(GetY()-starty) +
223 (GetZ()-startz)*(GetZ()-startz) );
224 AddTimeStep(TMath::Sqrt(l2));
230 //____________________________________________________________________________
231 Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
233 //------------------------------------------------------------------
234 //This function updates track parameters
235 //------------------------------------------------------------------
236 Double_t p[2]={c->GetY(), c->GetZ()};
237 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
239 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
242 AliWarning("Wrong invariant !");
246 if (chi2<0) return kTRUE;
248 AliTracker::FillResiduals(this,p,cov,c->GetVolumeId());
250 Int_t n=GetNumberOfClusters();
252 SetNumberOfClusters(n+1);
253 SetChi2(GetChi2()+chi2);
258 Bool_t AliITStrackV2::Invariant() const {
259 //------------------------------------------------------------------
260 // This function is for debugging purpose only
261 //------------------------------------------------------------------
262 Int_t n=GetNumberOfClusters();
264 Double_t sP2=GetParameter()[2];
265 if (TMath::Abs(sP2) >= kAlmost1){
266 if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2);
269 Double_t sC00=GetCovariance()[0];
270 if (sC00<=0 || sC00>9.) {
271 if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00);
274 Double_t sC11=GetCovariance()[2];
275 if (sC11<=0 || sC11>9.) {
276 if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11);
279 Double_t sC22=GetCovariance()[5];
280 if (sC22<=0 || sC22>1.) {
281 if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22);
284 Double_t sC33=GetCovariance()[9];
285 if (sC33<=0 || sC33>1.) {
286 if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33);
289 Double_t sC44=GetCovariance()[14];
290 if (sC44<=0 /*|| sC44>6e-5*/) {
291 if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44);
298 //____________________________________________________________________________
299 Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
300 //------------------------------------------------------------------
301 //This function propagates a track
302 //------------------------------------------------------------------
304 if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
307 AliWarning("Wrong invariant !");
314 Bool_t AliITStrackV2::MeanBudgetToPrimVertex(Double_t xyz[3], Double_t step, Double_t &d) const {
316 //-------------------------------------------------------------------
317 // Get the mean material budget between the actual point and the
318 // primary vertex. (L.Gaudichet)
319 //-------------------------------------------------------------------
321 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
322 Double_t vertexX = xyz[0]*cs + xyz[1]*sn;
324 Int_t nstep = Int_t((GetX()-vertexX)/step);
325 if (nstep<1) nstep = 1;
326 step = (GetX()-vertexX)/nstep;
328 // Double_t mparam[7], densMean=0, radLength=0, length=0;
330 Double_t p1[3], p2[3], x = GetX(), bz = GetBz();
335 for (Int_t i=0; i<nstep; i++) {
337 if (!GetXYZAt(x, bz, p2)) return kFALSE;
338 AliTracker::MeanMaterialBudget(p1, p2, mparam);
339 if (mparam[1]>900000) return kFALSE;
350 Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
351 //------------------------------------------------------------------
352 //This function improves angular track parameters
353 //------------------------------------------------------------------
354 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
355 //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
356 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
357 Double_t zv = xyz[2]; // local frame
359 Double_t dy = Par(0) - yv, dz = Par(1) - zv;
360 Double_t r2=GetX()*GetX() + dy*dy;
361 Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt());
362 Double_t beta2=p2/(p2 + GetMass()*GetMass());
363 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
364 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
365 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
367 Double_t cnv=GetBz()*kB2C;
369 Double_t dummy = 4/r2 - GetC()*GetC();
370 if (dummy < 0) return kFALSE;
371 Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy));
372 Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
373 sigma2p += Cov(0)/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
374 sigma2p += ers[1]*ers[1]/r2;
375 sigma2p += 0.25*Cov(14)*cnv*cnv*GetX()*GetX();
376 Double_t eps2p=sigma2p/(Cov(5) + sigma2p);
377 Par(0) += Cov(3)/(Cov(5) + sigma2p)*(parp - GetSnp());
378 Par(2) = eps2p*GetSnp() + (1 - eps2p)*parp;
383 Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2));
384 Double_t sigma2l=theta2;
385 sigma2l += Cov(2)/r2 + Cov(0)*dy*dy*dz*dz/(r2*r2*r2);
386 sigma2l += ers[2]*ers[2]/r2;
387 Double_t eps2l = sigma2l/(Cov(9) + sigma2l);
388 Par(1) += Cov(7 )/(Cov(9) + sigma2l)*(parl - Par(3));
389 Par(4) += Cov(13)/(Cov(9) + sigma2l)*(parl - Par(3));
390 Par(3) = eps2l*Par(3) + (1-eps2l)*parl;
395 if (!Invariant()) return kFALSE;
400 void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
401 //-----------------------------------------------------------------
402 // This function calculates dE/dX within the "low" and "up" cuts.
403 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
404 //-----------------------------------------------------------------
405 // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1
409 for (i=0; i<GetNumberOfClusters(); i++) {
410 Int_t idx=GetClusterIndex(i);
411 idx=(idx&0xf0000000)>>28;
412 if (idx>1) nc++; // Take only SSD and SDD
415 Int_t swap;//stupid sorting
418 for (i=0; i<nc-1; i++) {
419 if (fdEdxSample[i]<=fdEdxSample[i+1]) continue;
420 Float_t tmp=fdEdxSample[i];
421 fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp;
426 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX
427 // values from four ones choose
430 for (i=nl; i<nu; i++) dedx += fdEdxSample[i];
431 if (nu-nl>0) dedx /= (nu-nl);
436 Double_t AliITStrackV2::GetBz() const {
438 // returns Bz component of the magnetic field (kG)
440 if (AliTracker::UniformField()) return AliTracker::GetBz();
441 Double_t r[3]; GetXYZ(r);
442 return AliTracker::GetBz(r);
445 //____________________________________________________________________________
446 Bool_t AliITStrackV2::
447 GetPhiZat(Double_t r, Double_t &phi, Double_t &z) const {
448 //------------------------------------------------------------------
449 // This function returns the global cylindrical (phi,z) of the track
450 // position estimated at the radius r.
451 // The track curvature is neglected.
452 //------------------------------------------------------------------
453 Double_t d=GetD(0.,0.);
454 if (TMath::Abs(d) > r) return kFALSE;
456 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
457 if (TMath::Abs(d) > rcurr) return kFALSE;
458 Double_t phicurr=GetAlpha()+TMath::ASin(GetSnp());
460 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
461 z=GetZ()+GetTgl()*(TMath::Sqrt((r-d)*(r+d))-TMath::Sqrt((rcurr-d)*(rcurr+d)));
464 //____________________________________________________________________________
465 Bool_t AliITStrackV2::
466 GetLocalXat(Double_t r,Double_t &xloc) const {
467 //------------------------------------------------------------------
468 // This function returns the local x of the track
469 // position estimated at the radius r.
470 // The track curvature is neglected.
471 //------------------------------------------------------------------
472 Double_t d=GetD(0.,0.);
473 if (TMath::Abs(d) > r) return kFALSE;
475 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
476 Double_t phicurr=GetAlpha()+TMath::ASin(GetSnp());
477 Double_t phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
479 xloc=r*(TMath::Cos(phi)*TMath::Cos(GetAlpha())
480 +TMath::Sin(phi)*TMath::Sin(GetAlpha()));