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 ClassImp(AliITStrackV2)
33 //____________________________________________________________________________
34 AliITStrackV2::AliITStrackV2() : AliKalmanTrack(),
38 for(Int_t i=0; i<2*kMaxLayer; i++) fIndex[i]=-1;
39 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
43 //____________________________________________________________________________
44 AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c) throw (const Char_t *) :
46 fdEdx(t.GetITSsignal()),
49 //------------------------------------------------------------------
50 // Conversion ESD track -> ITS track.
51 // If c==kTRUE, create the ITS track out of the constrained params.
52 //------------------------------------------------------------------
53 const AliExternalTrackParam *par=&t;
55 par=t.GetConstrainedParam();
56 if (!par) throw "AliITStrackV2: conversion failed !\n";
58 Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance());
60 //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
62 SetLabel(t.GetLabel());
64 SetNumberOfClusters(t.GetITSclusters(fIndex));
66 if (t.GetStatus()&AliESDtrack::kTIME) {
68 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
69 SetIntegratedLength(t.GetIntegratedLength());
72 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
75 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
76 fESDtrack->UpdateTrackParams(this,flags);
79 //____________________________________________________________________________
80 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
83 fESDtrack(t.fESDtrack)
85 //------------------------------------------------------------------
87 //------------------------------------------------------------------
89 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
90 for (i=0; i<2*kMaxLayer; i++) fIndex[i]=t.fIndex[i];
93 //_____________________________________________________________________________
94 Int_t AliITStrackV2::Compare(const TObject *o) const {
95 //-----------------------------------------------------------------
96 // This function compares tracks according to the their curvature
97 //-----------------------------------------------------------------
98 AliITStrackV2 *t=(AliITStrackV2*)o;
99 //Double_t co=TMath::Abs(t->Get1Pt());
100 //Double_t c =TMath::Abs(Get1Pt());
101 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
102 Double_t c =GetSigmaY2()*GetSigmaZ2();
104 else if (c<co) return -1;
108 //____________________________________________________________________________
110 AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
112 //------------------------------------------------------------------
113 //This function propagates a track to the minimal distance from the origin
114 //------------------------------------------------------------------
116 if (PropagateToDCA(v,bz,kVeryBig))
117 if (AliExternalTrackParam::CorrectForMaterial(d,x0,GetMass())) return kTRUE;
121 //____________________________________________________________________________
122 Bool_t AliITStrackV2::
123 GetGlobalXYZat(Double_t xk, Double_t &x, Double_t &y, Double_t &z) const {
124 //------------------------------------------------------------------
125 //This function returns a track position in the global system
126 //------------------------------------------------------------------
128 Bool_t rc=GetXYZAt(xk, AliTracker::GetBz(), r);
129 x=r[0]; y=r[1]; z=r[2];
133 //_____________________________________________________________________________
134 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
135 //-----------------------------------------------------------------
136 // This function calculates a predicted chi2 increment.
137 //-----------------------------------------------------------------
138 Double_t p[2]={c->GetY(), c->GetZ()};
139 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
140 return AliExternalTrackParam::GetPredictedChi2(p,cov);
143 //____________________________________________________________________________
144 Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
145 //------------------------------------------------------------------
146 //This function propagates a track
147 //------------------------------------------------------------------
148 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
151 if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
152 if (!AliExternalTrackParam::CorrectForMaterial(d,x0,GetMass())) return kFALSE;
154 Double_t x=GetX(), y=GetY(), z=GetZ();
155 if (IsStartedTimeIntegral() && x>oldX) {
156 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
157 AddTimeStep(TMath::Sqrt(l2));
163 //____________________________________________________________________________
164 Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
166 //------------------------------------------------------------------
167 //This function updates track parameters
168 //------------------------------------------------------------------
169 Double_t p[2]={c->GetY(), c->GetZ()};
170 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
172 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
175 AliWarning("Wrong invariant !");
179 if (chi2<0) return kTRUE;
181 Int_t n=GetNumberOfClusters();
183 SetNumberOfClusters(n+1);
184 SetChi2(GetChi2()+chi2);
189 Bool_t AliITStrackV2::Invariant() const {
190 //------------------------------------------------------------------
191 // This function is for debugging purpose only
192 //------------------------------------------------------------------
193 Int_t n=GetNumberOfClusters();
195 Double_t sP2=GetParameter()[2];
196 if (TMath::Abs(sP2) >= kAlmost1){
197 if (n>kWARN) Warning("Invariant","fP2=%f\n",sP2);
200 Double_t sC00=GetCovariance()[0];
201 if (sC00<=0 || sC00>9.) {
202 if (n>kWARN) Warning("Invariant","fC00=%f\n",sC00);
205 Double_t sC11=GetCovariance()[2];
206 if (sC11<=0 || sC11>9.) {
207 if (n>kWARN) Warning("Invariant","fC11=%f\n",sC11);
210 Double_t sC22=GetCovariance()[5];
211 if (sC22<=0 || sC22>1.) {
212 if (n>kWARN) Warning("Invariant","fC22=%f\n",sC22);
215 Double_t sC33=GetCovariance()[9];
216 if (sC33<=0 || sC33>1.) {
217 if (n>kWARN) Warning("Invariant","fC33=%f\n",sC33);
220 Double_t sC44=GetCovariance()[14];
221 if (sC44<=0 /*|| sC44>6e-5*/) {
222 if (n>kWARN) Warning("Invariant","fC44=%f\n",sC44);
229 //____________________________________________________________________________
230 Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
231 //------------------------------------------------------------------
232 //This function propagates a track
233 //------------------------------------------------------------------
235 if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
238 AliWarning("Wrong invariant !");
245 Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
246 //------------------------------------------------------------------
247 //This function improves angular track parameters
248 //------------------------------------------------------------------
249 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
250 //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
251 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
252 Double_t zv = xyz[2]; // local frame
254 Double_t dy = Par(0) - yv, dz = Par(1) - zv;
255 Double_t r2=GetX()*GetX() + dy*dy;
256 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
257 Double_t beta2=p2/(p2 + GetMass()*GetMass());
258 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
259 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
260 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
262 Double_t cnv=GetBz()*kB2C;
264 Double_t dummy = 4/r2 - GetC()*GetC();
265 if (dummy < 0) return kFALSE;
266 Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy));
267 Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl());
268 sigma2p += Cov(0)/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2);
269 sigma2p += ers[1]*ers[1]/r2;
270 sigma2p += 0.25*Cov(14)*cnv*cnv*GetX()*GetX();
271 Double_t eps2p=sigma2p/(Cov(2) + sigma2p);
272 Par(0) += Cov(3)/(Cov(5) + sigma2p)*(parp - GetSnp());
273 Par(2) = eps2p*GetSnp() + (1 - eps2p)*parp;
278 Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2));
279 Double_t sigma2l=theta2;
280 sigma2l += Cov(2)/r2 + Cov(0)*dy*dy*dz*dz/(r2*r2*r2);
281 sigma2l += ers[2]*ers[2]/r2;
282 Double_t eps2l = sigma2l/(Cov(9) + sigma2l);
283 Par(1) += Cov(7 )/(Cov(9) + sigma2l)*(parl - Par(3));
284 Par(4) += Cov(13)/(Cov(9) + sigma2l)*(parl - Par(3));
285 Par(3) = eps2l*Par(3) + (1-eps2l)*parl;
287 Cov(13)*= (eps2l/cnv/cnv);
290 if (!Invariant()) return kFALSE;
295 void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
296 //-----------------------------------------------------------------
297 // This function calculates dE/dX within the "low" and "up" cuts.
298 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
299 //-----------------------------------------------------------------
300 // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1
304 for (i=0; i<GetNumberOfClusters(); i++) {
305 Int_t idx=GetClusterIndex(i);
306 idx=(idx&0xf0000000)>>28;
307 if (idx>1) nc++; // Take only SSD and SDD
310 Int_t swap;//stupid sorting
313 for (i=0; i<nc-1; i++) {
314 if (fdEdxSample[i]<=fdEdxSample[i+1]) continue;
315 Float_t tmp=fdEdxSample[i];
316 fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp;
321 Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX
322 // values from four ones choose
325 for (i=nl; i<nu; i++) dedx += fdEdxSample[i];
326 if (nu-nl>0) dedx /= (nu-nl);
331 Double_t AliITStrackV2::GetBz() const {
333 // returns Bz component of the magnetic field (kG)
335 if (AliTracker::UniformField()) return AliTracker::GetBz();
336 Double_t r[3]; GetXYZ(r);
337 return AliTracker::GetBz(r);