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 **************************************************************************/
16 ///////////////////////////////////////////////////////////////////////////
17 // Implementation of the ITS track class
19 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
20 // dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
21 ///////////////////////////////////////////////////////////////////////////
24 #include "AliCluster.h"
25 #include "AliTracker.h"
26 #include "AliESDtrack.h"
27 #include "AliITStrackV2.h"
29 const Int_t AliITStrackV2::fgkWARN = 5;
31 ClassImp(AliITStrackV2)
34 //____________________________________________________________________________
35 AliITStrackV2::AliITStrackV2() : AliKalmanTrack(),
39 for(Int_t i=0; i<2*kMaxLayer; i++) fIndex[i]=-1;
40 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
44 //____________________________________________________________________________
45 AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c) throw (const Char_t *) :
47 fdEdx(t.GetITSsignal()),
50 //------------------------------------------------------------------
51 // Conversion ESD track -> ITS track.
52 // If c==kTRUE, create the ITS track out of the constrained params.
53 //------------------------------------------------------------------
54 const AliExternalTrackParam *par=&t;
56 par=t.GetConstrainedParam();
57 if (!par) throw "AliITStrackV2: conversion failed !\n";
59 Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance());
61 //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
63 SetLabel(t.GetLabel());
65 SetNumberOfClusters(t.GetITSclusters(fIndex));
67 if (t.GetStatus()&AliESDtrack::kTIME) {
69 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
70 SetIntegratedLength(t.GetIntegratedLength());
73 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
76 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
77 fESDtrack->UpdateTrackParams(this,flags);
80 //____________________________________________________________________________
81 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
84 fESDtrack(t.fESDtrack)
86 //------------------------------------------------------------------
88 //------------------------------------------------------------------
90 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
91 for (i=0; i<2*kMaxLayer; i++) fIndex[i]=t.fIndex[i];
94 //_____________________________________________________________________________
95 Int_t AliITStrackV2::Compare(const TObject *o) const {
96 //-----------------------------------------------------------------
97 // This function compares tracks according to the their curvature
98 //-----------------------------------------------------------------
99 AliITStrackV2 *t=(AliITStrackV2*)o;
100 //Double_t co=TMath::Abs(t->Get1Pt());
101 //Double_t c =TMath::Abs(Get1Pt());
102 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
103 Double_t c =GetSigmaY2()*GetSigmaZ2();
105 else if (c<co) return -1;
109 //____________________________________________________________________________
111 AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
113 //------------------------------------------------------------------
114 //This function propagates a track to the minimal distance from the origin
115 //------------------------------------------------------------------
117 if (PropagateToDCA(v,bz,kVeryBig))
118 if (AliExternalTrackParam::CorrectForMaterial(d,x0,GetMass())) return kTRUE;
122 //____________________________________________________________________________
123 Bool_t AliITStrackV2::
124 GetGlobalXYZat(Double_t xk, Double_t &x, Double_t &y, Double_t &z) const {
125 //------------------------------------------------------------------
126 //This function returns a track position in the global system
127 //------------------------------------------------------------------
129 Bool_t rc=GetXYZAt(xk, AliTracker::GetBz(), r);
130 x=r[0]; y=r[1]; z=r[2];
134 //_____________________________________________________________________________
135 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
136 //-----------------------------------------------------------------
137 // This function calculates a predicted chi2 increment.
138 //-----------------------------------------------------------------
139 Double_t p[2]={c->GetY(), c->GetZ()};
140 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
141 return AliExternalTrackParam::GetPredictedChi2(p,cov);
144 //____________________________________________________________________________
145 Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
146 //------------------------------------------------------------------
147 //This function propagates a track
148 //------------------------------------------------------------------
149 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
152 if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
153 if (!AliExternalTrackParam::CorrectForMaterial(d,x0,GetMass())) return kFALSE;
155 Double_t x=GetX(), y=GetY(), z=GetZ();
156 if (IsStartedTimeIntegral() && x>oldX) {
157 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
158 AddTimeStep(TMath::Sqrt(l2));
164 //____________________________________________________________________________
165 Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
167 //------------------------------------------------------------------
168 //This function updates track parameters
169 //------------------------------------------------------------------
170 Double_t p[2]={c->GetY(), c->GetZ()};
171 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
173 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
176 AliWarning("Wrong invariant !");
180 if (chi2<0) return kTRUE;
182 Int_t n=GetNumberOfClusters();
184 SetNumberOfClusters(n+1);
185 SetChi2(GetChi2()+chi2);
190 Bool_t AliITStrackV2::Invariant() const {
191 //------------------------------------------------------------------
192 // This function is for debugging purpose only
193 //------------------------------------------------------------------
194 Int_t n=GetNumberOfClusters();
196 Double_t sP2=GetParameter()[2];
197 if (TMath::Abs(sP2) >= kAlmost1){
198 if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2);
201 Double_t sC00=GetCovariance()[0];
202 if (sC00<=0 || sC00>9.) {
203 if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00);
206 Double_t sC11=GetCovariance()[2];
207 if (sC11<=0 || sC11>9.) {
208 if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11);
211 Double_t sC22=GetCovariance()[5];
212 if (sC22<=0 || sC22>1.) {
213 if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22);
216 Double_t sC33=GetCovariance()[9];
217 if (sC33<=0 || sC33>1.) {
218 if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33);
221 Double_t sC44=GetCovariance()[14];
222 if (sC44<=0 /*|| sC44>6e-5*/) {
223 if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44);
230 //____________________________________________________________________________
231 Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
232 //------------------------------------------------------------------
233 //This function propagates a track
234 //------------------------------------------------------------------
236 if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
239 AliWarning("Wrong invariant !");
246 Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
247 //------------------------------------------------------------------
248 //This function improves angular track parameters
249 //------------------------------------------------------------------
250 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
251 //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
252 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
253 Double_t zv = xyz[2]; // local frame
255 Double_t dy = Par(0) - yv, dz = Par(1) - zv;
256 Double_t r2=GetX()*GetX() + dy*dy;
257 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
258 Double_t beta2=p2/(p2 + GetMass()*GetMass());
259 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
260 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
261 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
263 Double_t cnv=GetBz()*kB2C;
265 Double_t dummy = 4/r2 - GetC()*GetC();
266 if (dummy < 0) return kFALSE;
267 Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy));
268 Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
269 sigma2p += Cov(0)/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
270 sigma2p += ers[1]*ers[1]/r2;
271 sigma2p += 0.25*Cov(14)*cnv*cnv*GetX()*GetX();
272 Double_t eps2p=sigma2p/(Cov(5) + sigma2p);
273 Par(0) += Cov(3)/(Cov(5) + sigma2p)*(parp - GetSnp());
274 Par(2) = eps2p*GetSnp() + (1 - eps2p)*parp;
279 Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2));
280 Double_t sigma2l=theta2;
281 sigma2l += Cov(2)/r2 + Cov(0)*dy*dy*dz*dz/(r2*r2*r2);
282 sigma2l += ers[2]*ers[2]/r2;
283 Double_t eps2l = sigma2l/(Cov(9) + sigma2l);
284 Par(1) += Cov(7 )/(Cov(9) + sigma2l)*(parl - Par(3));
285 Par(4) += Cov(13)/(Cov(9) + sigma2l)*(parl - Par(3));
286 Par(3) = eps2l*Par(3) + (1-eps2l)*parl;
291 if (!Invariant()) return kFALSE;
296 void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
297 //-----------------------------------------------------------------
298 // This function calculates dE/dX within the "low" and "up" cuts.
299 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
300 //-----------------------------------------------------------------
301 // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1
305 for (i=0; i<GetNumberOfClusters(); i++) {
306 Int_t idx=GetClusterIndex(i);
307 idx=(idx&0xf0000000)>>28;
308 if (idx>1) nc++; // Take only SSD and SDD
311 Int_t swap;//stupid sorting
314 for (i=0; i<nc-1; i++) {
315 if (fdEdxSample[i]<=fdEdxSample[i+1]) continue;
316 Float_t tmp=fdEdxSample[i];
317 fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp;
322 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX
323 // values from four ones choose
326 for (i=nl; i<nu; i++) dedx += fdEdxSample[i];
327 if (nu-nl>0) dedx /= (nu-nl);
332 Double_t AliITStrackV2::GetBz() const {
334 // returns Bz component of the magnetic field (kG)
336 if (AliTracker::UniformField()) return AliTracker::GetBz();
337 Double_t r[3]; GetXYZ(r);
338 return AliTracker::GetBz(r);
341 //____________________________________________________________________________
342 Bool_t AliITStrackV2::
343 GetPhiZat(Double_t rk, Double_t &phik, Double_t &zk) const {
344 //------------------------------------------------------------------
345 // This function returns the global cylindrical (phik,zk) of the track
346 // position estimated at the radius rk.
347 // The track curvature is neglected.
348 //------------------------------------------------------------------
349 Double_t d=GetD(0.,0.);
350 if (TMath::Abs(d) > rk) return kFALSE;
352 Double_t r=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
353 Double_t phi=GetAlpha()+TMath::ASin(GetSnp());
355 phik=phi+TMath::ASin(d/rk)-TMath::ASin(d/r);
356 zk=GetZ()+GetTgl()*(TMath::Sqrt(rk*rk-d*d) - TMath::Sqrt(r*r-d*d));