STEER/AliMixedEvent.cxx

   1 /**************************************************************************
   2  * Copyright(c) 1998-2007, ALICE Experiment at CERN, All rights reserved. *
   3  *                                                                        *
   4  * Author: The ALICE Off-line Project.                                    *
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  10  * copies and that both the copyright notice and this permission notice   *
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  13  * provided "as is" without express or implied warranty.                  *
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  15
  16 /* $Id$ */
  17
  18
  19 //-------------------------------------------------------------------------
  20 //                          Class AliMixedEvent
  21 // VEvent which is the container of several VEvents
  22 // Use Case: Event Mixing
  23 // Origin: Andreas Morsch, CERN, Andreas.Morsch@cern.ch
  24 //-------------------------------------------------------------------------
  25
  26
  27 #include "AliMixedEvent.h"
  28 #include "AliESDVertex.h"
  29 #include "AliExternalTrackParam.h"
  30 #include "AliESDtrack.h"
  31 #include "TVector3.h"
  32 #include "AliAODVertex.h"
  33 #include <TMath.h>
  34 #include <TMatrix.h>
  35 #include <TMatrixD.h>
  36
  37 ClassImp(AliMixedEvent)
  38
  39
  40 AliMixedEvent::AliMixedEvent() :
  41     AliVEvent(),
  42     fEventList(),
  43     fNEvents(0),
  44     fNumberOfTracks(0),
  45     fNTracksCumul(0)
  46 {
  47     // Default constructor
  48 }
  49
  50 AliMixedEvent::AliMixedEvent(const AliMixedEvent& Evnt) :
  51     AliVEvent(Evnt),
  52     fEventList(),
  53     fNEvents(0),
  54     fNumberOfTracks(0),
  55     fNTracksCumul(0)
  56 { } // Copy constructor
  57
  58 AliMixedEvent& AliMixedEvent::operator=(const AliMixedEvent& vEvnt)
  59 { if (this!=&vEvnt) {
  60     AliVEvent::operator=(vEvnt);
  61   }
  62
  63   return *this;
  64 }
  65
  66
  67 void AliMixedEvent::AddEvent(AliVEvent* evt)
  68 {
  69     // Add a new event to the list
  70     fEventList.AddLast(evt);
  71 }
  72
  73
  74 void AliMixedEvent::Init()
  75 {
  76     // Initialize meta information
  77     fNEvents = fEventList.GetEntries();
  78     fNTracksCumul = new Int_t[fNEvents];
  79     fNumberOfTracks = 0;
  80     TIter next(&fEventList);
  81     AliVEvent* event;
  82     Int_t iev = 0;
  83
  84     while((event = (AliVEvent*)next())) {
  85         fNTracksCumul[iev++] = fNumberOfTracks;
  86         fNumberOfTracks += (event->GetNumberOfTracks());
  87     }
  88 }
  89
  90
  91 AliVParticle* AliMixedEvent::GetTrack(Int_t i) const
  92 {
  93     // Return track # i
  94     Int_t iEv  = TMath::BinarySearch(fNEvents, fNTracksCumul, i);
  95     while((iEv < (fNEvents - 1)) && (fNTracksCumul[iEv] == fNTracksCumul[iEv+1])) {iEv++;}
  96
  97     Int_t irel = i - fNTracksCumul[iEv];
  98     AliVEvent* evt = (AliVEvent*) (fEventList.At(iEv));
  99     return (evt->GetTrack(irel));
 100 }
 101
 102 const AliVVertex* AliMixedEvent::GetEventVertex(Int_t i) const
 103 {
 104     // Return track # i
 105     Int_t iEv  = TMath::BinarySearch(fNEvents, fNTracksCumul, i);
 106     while((iEv < (fNEvents - 1)) && (fNTracksCumul[iEv] == fNTracksCumul[iEv+1])) {iEv++;}
 107     AliVEvent* evt = (AliVEvent*) (fEventList.At(iEv));
 108     return (evt->GetPrimaryVertex());
 109 }
 110
 111 void AliMixedEvent::Reset()
 112 {
 113     // Reset the event
 114     fEventList.Clear();
 115     fNEvents = 0;
 116     fNumberOfTracks = 0;
 117     if (fNTracksCumul) {
 118         delete[]  fNTracksCumul;
 119         fNTracksCumul = 0;
 120     }
 121 }
 122
 123 Int_t AliMixedEvent::EventIndex(Int_t itrack)
 124 {
 125   // Return the event index for track #itrack
 126   return  TMath::BinarySearch(fNEvents, fNTracksCumul, itrack);
 127 }
 128
 129 void AliMixedEvent::ComputeVtx(TObjArray *vertices, Double_t *pos,Double_t *sig){
 130 //
 131 // Calculate the mean vertex psoitions from events in the buffer
 132
 133     Int_t nentries = vertices->GetEntriesFast();
 134     Double_t sum[3]={0.,0.,0.};
 135     Double_t sumsigma[6]={0.,0.,0.,0.,0.,0.};
 136
 137     for(Int_t ivtx = 0; ivtx < nentries; ivtx++){
 138         AliAODVertex *vtx=(AliAODVertex*)vertices->UncheckedAt(ivtx);
 139         if(!vtx) return;
 140         Double_t covariance[6];
 141         vtx->GetCovMatrix(covariance);
 142
 143         Double_t vtxPos[3];
 144         vtx->GetXYZ(vtxPos);
 145         if(covariance[0]==0) continue;
 146         sum[0]+=vtxPos[0]*(1./covariance[0]);
 147         sumsigma[0]+=(1./covariance[0]);
 148         if(covariance[2]==0) continue;
 149         sum[1]+=vtxPos[1]*(1./covariance[2]);
 150         sumsigma[2]+=(1./covariance[2]);
 151         if(covariance[5]==0) continue;
 152         sum[2]+=vtxPos[2]*(1./covariance[5]);
 153         sumsigma[5]+=(1./covariance[5]);
 154         if(covariance[1]==0) continue;
 155         sumsigma[1]+=(1./covariance[1]);
 156         if(covariance[3]==0) continue;
 157         sumsigma[3]+=(1./covariance[3]);
 158         if(covariance[4]==0) continue;
 159         sumsigma[4]+=(1./covariance[4]);
 160     }
 161
 162     for(Int_t i=0;i<3;i++){
 163         if(sumsigma[i]==0) continue;
 164         pos[i]=sum[i]/sumsigma[i];
 165     }
 166     for(Int_t i2=0;i2<6;i2++){
 167         if(sumsigma[i2]==0) {sig[i2]=0.; continue;}
 168         sig[i2]=1./sumsigma[i2];
 169     }
 170     return;
 171 }
 172