ITS/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  *                                                                        *
   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  **************************************************************************/
  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 }