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[u/mrichter/AliRoot.git] / ITS / ITSrec / AliITStrackMI.cxx
1 /**************************************************************************
2  * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3  *                                                                        *
4  * Author: The ALICE Off-line Project.                                    *
5  * Contributors are mentioned in the code where appropriate.              *
6  *                                                                        *
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8  * documentation strictly for non-commercial purposes is hereby granted   *
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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  **************************************************************************/
15
16 //-------------------------------------------------------------------------
17 //                Implementation of the ITS track class
18 //
19 //          Origin: Marian Ivanov, CERN, Marian.Ivanov@cern.ch
20 //     dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
21 //-------------------------------------------------------------------------
22
23 /* $Id$ */
24
25 #include <TMatrixD.h>
26
27 #include <TMath.h>
28
29 #include "AliITSRecoParam.h"
30 #include "AliCluster.h"
31 #include "AliESDtrack.h"
32 #include "AliITSgeomTGeo.h"
33 #include "AliITStrackMI.h"
34
35 ClassImp(AliITStrackMI)
36
37 const Int_t kWARN=5;
38
39 //____________________________________________________________________________
40 AliITStrackMI::AliITStrackMI():AliITStrackV2(),
41 fNUsed(0),
42 fNSkipped(0),
43 fNDeadZone(0),                         
44 fReconstructed(kFALSE),
45 fExpQ(40),
46 fChi22(0),
47 fdEdxMismatch(0),
48 fConstrain(kFALSE),
49 fWinner(0),
50 fGoldV0(kFALSE)
51
52 {
53   //constructor
54     for(Int_t i=0; i<AliITSgeomTGeo::GetNLayers(); i++) fClIndex[i]=-1;
55     for(Int_t i=0; i<6; i++) { fNy[i]=0; fNz[i]=0; fNormQ[i]=0; fNormChi2[i]=1000; fDeadZoneProbability[i]=0;}
56     for(Int_t i=0; i<12; i++) {fDy[i]=0; fDz[i]=0; fSigmaY[i]=0; fSigmaZ[i]=0; fSigmaYZ[i]=0; fChi2MIP[i]=0;}
57     fD[0]=0; fD[1]=0;
58     fDnorm[0]=0; fDnorm[1]=0;
59 }
60
61 //____________________________________________________________________________
62 AliITStrackMI::AliITStrackMI(AliESDtrack& t,Bool_t c):
63 AliITStrackV2(t,c),
64 fNUsed(0),
65 fNSkipped(0),
66 fNDeadZone(0),
67 fReconstructed(kFALSE),
68 fExpQ(40),
69 fChi22(0),
70 fdEdxMismatch(0),
71 fConstrain(kFALSE),
72 fWinner(0),
73 fGoldV0(kFALSE) {
74   //------------------------------------------------------------------
75   // Conversion ESD track -> ITS track.
76   // If c==kTRUE, create the ITS track out of the constrained params.
77   //------------------------------------------------------------------
78   for(Int_t i=0; i<6; i++) {fClIndex[i]=-1; fNy[i]=0; fNz[i]=0; fNormQ[i]=0; fNormChi2[i]=1000; fDeadZoneProbability[i]=0;}
79   for(Int_t i=0; i<12; i++) {fDy[i]=0; fDz[i]=0; fSigmaY[i]=0; fSigmaZ[i]=0; fSigmaYZ[i]=0; fChi2MIP[i]=0;}
80   fD[0]=0; fD[1]=0;
81   fDnorm[0]=0; fDnorm[1]=0;
82
83 }
84
85 //____________________________________________________________________________
86 AliITStrackMI::AliITStrackMI(const AliITStrackMI& t) : AliITStrackV2(t),
87 fNUsed(t.fNUsed),
88 fNSkipped(t.fNSkipped),
89 fNDeadZone(t.fNDeadZone),
90 fReconstructed(t.fReconstructed),
91 fExpQ(t.fExpQ),
92 fChi22(t.fChi22),
93 fdEdxMismatch(t.fdEdxMismatch),
94 fConstrain(t.fConstrain),
95 fWinner(0),
96 fGoldV0(t.fGoldV0) {
97   //------------------------------------------------------------------
98   //Copy constructor
99   //------------------------------------------------------------------
100   fLab = t.fLab;
101   fFakeRatio = t.fFakeRatio;
102
103   fD[0]=t.fD[0]; fD[1]=t.fD[1];
104   fDnorm[0] = t.fDnorm[0]; fDnorm[1]=t.fDnorm[1];
105   for(Int_t i=0; i<6; i++) {
106     fClIndex[i]= t.fClIndex[i]; fNy[i]=t.fNy[i]; fNz[i]=t.fNz[i]; fNormQ[i]=t.fNormQ[i]; fNormChi2[i] = t.fNormChi2[i];  fDeadZoneProbability[i]=t.fDeadZoneProbability[i];
107   }
108   for(Int_t i=0; i<12; i++) {fDy[i]=t.fDy[i]; fDz[i]=t.fDz[i]; 
109     fSigmaY[i]=t.fSigmaY[i]; fSigmaZ[i]=t.fSigmaZ[i]; fSigmaYZ[i]=t.fSigmaYZ[i]; fChi2MIP[i]=t.fChi2MIP[i];}
110   //memcpy(fDy,t.fDy,6*sizeof(Float_t));
111   //memcpy(fDz,t.fDz,6*sizeof(Float_t));
112   //memcpy(fSigmaY,t.fSigmaY,6*sizeof(Float_t));
113   //memcpy(fSigmaZ,t.fSigmaZ,6*sizeof(Float_t));
114   //memcpy(fChi2MIP,t.fChi2MIP,12*sizeof(Float_t));  
115 }
116
117 //_____________________________________________________________________________
118 Int_t AliITStrackMI::Compare(const TObject *o) const {
119   //-----------------------------------------------------------------
120   // This function compares tracks according to the their curvature
121   //-----------------------------------------------------------------
122   AliITStrackMI *t=(AliITStrackMI*)o;
123   //Double_t co=TMath::Abs(t->Get1Pt());
124   //Double_t c =TMath::Abs(Get1Pt());
125   Double_t co=t->GetSigmaY2()*t->GetSigmaZ2()*(0.5+TMath::Sqrt(0.5*t->fD[0]*t->fD[0]+t->fD[1]*t->fD[1]));
126   Double_t c =GetSigmaY2()*GetSigmaZ2()*(0.5+TMath::Sqrt(0.5*fD[0]*fD[0]+fD[1]*fD[1]));
127   if (c>co) return 1;
128   else if (c<co) return -1;
129   return 0;
130 }
131
132
133 Double_t AliITStrackMI::GetPredictedChi2MI(Double_t cy, Double_t cz, Double_t cerry, Double_t cerrz, Double_t covyz) const
134 {
135   //-----------------------------------------------------------------
136   // This function calculates a predicted chi2 increment.
137   //-----------------------------------------------------------------
138   Double_t p[2]={cy, cz};
139   Double_t cov[3]={cerry*cerry, covyz, cerrz*cerrz};
140   return AliExternalTrackParam::GetPredictedChi2(p,cov);
141 }
142
143 //____________________________________________________________________________
144 Bool_t AliITStrackMI::UpdateMI(const AliCluster *c, Double_t chi2, Int_t index) {
145   //------------------------------------------------------------------
146   //This function updates track parameters
147   //------------------------------------------------------------------
148   Double_t dy=c->GetY() - GetY(), dz=c->GetZ() - GetZ();
149   Int_t layer = (index & 0xf0000000) >> 28;
150   fDy[layer] = dy;
151   fDz[layer] = dz;
152   fSigmaY[layer] = TMath::Sqrt(c->GetSigmaY2()+GetSigmaY2());
153   fSigmaZ[layer] = TMath::Sqrt(c->GetSigmaZ2()+GetSigmaZ2());
154   fSigmaYZ[layer] = c->GetSigmaYZ()+GetSigmaZY();
155
156
157   return Update(c,chi2,index);
158 }
159
160 Int_t AliITStrackMI::GetProlongationFast(Double_t alp, Double_t xk,Double_t &y, Double_t &z)
161 {
162   //-----------------------------------------------------------------------------
163   //get fast prolongation 
164   //-----------------------------------------------------------------------------
165   Double_t ca=TMath::Cos(alp-GetAlpha()), sa=TMath::Sin(alp-GetAlpha());
166   Double_t cf=TMath::Sqrt((1.-GetSnp())*(1.+GetSnp()));  
167   // **** rotation **********************  
168   y= -GetX()*sa + GetY()*ca;
169   // **** translation ******************  
170   Double_t dx = xk- GetX()*ca - GetY()*sa;
171   Double_t f1=GetSnp()*ca - cf*sa, f2=f1 + GetC()*dx;
172   if (TMath::Abs(f2) >= 0.9999) {
173     return 0;
174   }
175   Double_t r1=TMath::Sqrt((1.-f1)*(1.+f1)), r2=TMath::Sqrt((1.-f2)*(1.+f2));  
176   y += dx*(f1+f2)/(r1+r2);
177   z  = GetZ()+dx*(f1+f2)/(f1*r2 + f2*r1)*GetTgl();  
178   return 1;
179 }
180
181
182 Bool_t AliITStrackMI::IsGoldPrimary()
183 {
184   //
185   // Indicates gold pimary track
186   //
187   Bool_t isGold=kTRUE;
188   if (!fConstrain) return kFALSE;                // 
189   if (fNDeadZone+fNDeadZone<5.5) isGold =  kFALSE; // short track
190   //
191   if (fChi2MIP[0]*fChi2MIP[3]>2) isGold = kFALSE; // RS: cut on chi2*interpolated_chi2
192   if (fChi2/Float_t(fN)>2.){
193     if (fChi2MIP[0]+fNUsed>3.5) isGold = kFALSE;    
194   }
195   if (fChi2MIP[2]>4.5) isGold = kFALSE;         //back propagation chi2
196   //
197   if (fDnorm[0]>0&&fDnorm[1]>0){
198     const Float_t distcut2 =2.5*2.5;  //normalize distance  cut 
199     Float_t dist2 = fD[0]*fD[0]/(fDnorm[0]*fDnorm[0])+fD[1]*fD[1]/(fDnorm[1]*fDnorm[1]);  //normalize distance to the vertex (pools)
200     if (dist2>distcut2) isGold = kFALSE;
201   }
202   return isGold;
203 }