PWG4/UserTasks/EmcalTasks/AliEmcalEsdTpcTrackTask.cxx

   1 // $Id$
   2 //
   3 // Task to constrain TPC tracks to vertex
   4 //
   5 //
   6
   7 #include <TClonesArray.h>
   8 #include <TGeoGlobalMagField.h>
   9 #include "AliAnalysisManager.h"
  10 #include "AliESDEvent.h"
  11 #include "AliESDtrackCuts.h"
  12 #include "AliEmcalEsdTpcTrackTask.h"
  13 #include "AliMagF.h"
  14
  15 ClassImp(AliEmcalEsdTpcTrackTask)
  16
  17 //________________________________________________________________________
  18 AliEmcalEsdTpcTrackTask::AliEmcalEsdTpcTrackTask() :
  19   AliAnalysisTaskSE(),
  20   fEsdTrackCuts(0),
  21   fTracksName(),
  22   fEsdEv(0),
  23   fTracks(0)
  24 {
  25   // Constructor
  26 }
  27
  28 //________________________________________________________________________
  29 AliEmcalEsdTpcTrackTask::AliEmcalEsdTpcTrackTask(const char *name) :
  30   AliAnalysisTaskSE(name),
  31   fEsdTrackCuts(0),
  32   fTracksName("TpcSpdVertexConstrainedTracks"),
  33   fEsdEv(0),
  34   fTracks(0)
  35 {
  36   // Constructor
  37   fBranchNames = "ESD:SPDVertex.,Tracks";
  38 }
  39
  40 //________________________________________________________________________
  41 AliEmcalEsdTpcTrackTask::~AliEmcalEsdTpcTrackTask()
  42 {
  43   //Destructor
  44
  45   delete fEsdTrackCuts;
  46 }
  47
  48 //________________________________________________________________________
  49 void AliEmcalEsdTpcTrackTask::UserCreateOutputObjects()
  50 {
  51   // Create histograms
  52
  53   fTracks = new TClonesArray("AliESDtrack");
  54   fTracks->SetName(fTracksName);
  55
  56   if (!fEsdTrackCuts) {
  57     AliInfo("No track cuts given, creating default cuts");
  58     fEsdTrackCuts = AliESDtrackCuts::GetStandardTPCOnlyTrackCuts();
  59     fEsdTrackCuts->SetPtRange(0.15,1e3);
  60   }
  61 }
  62
  63 //________________________________________________________________________
  64 void AliEmcalEsdTpcTrackTask::UserExec(Option_t *)
  65 {
  66   // Main loop, called for each event.
  67
  68   fEsdEv = dynamic_cast<AliESDEvent*>(InputEvent());
  69   if (!fEsdEv) {
  70     AliError("Task works only on ESD events, returning");
  71     return;
  72   }
  73
  74   AliAnalysisManager *am = AliAnalysisManager::GetAnalysisManager();
  75   if (!am) {
  76     AliError("Manager zero, returning");
  77     return;
  78   }
  79
  80   // add tracks to event if not yet there
  81   if (!(InputEvent()->FindListObject(fTracksName)))
  82     InputEvent()->AddObject(fTracks);
  83
  84   am->LoadBranch("AliESDRun.");
  85   am->LoadBranch("AliESDHeader.");
  86   if (!TGeoGlobalMagField::Instance()->GetField()) { // construct field map
  87     const AliESDRun *erun = fEsdEv->GetESDRun();
  88     AliMagF *field = AliMagF::CreateFieldMap(erun->GetCurrentL3(),
  89                                              erun->GetCurrentDip(),
  90                                              AliMagF::kConvLHC,
  91                                              kFALSE,
  92                                              erun->GetBeamEnergy(),
  93                                              erun->GetBeamType());
  94     TGeoGlobalMagField::Instance()->SetField(field);
  95   }
  96
  97   am->LoadBranch("SPDVertex.");
  98   const AliESDVertex *vtxSPD = fEsdEv->GetPrimaryVertexSPD();
  99   if (!vtxSPD) {
 100     AliError("No SPD vertex, returning");
 101     return;
 102   }
 103
 104   am->LoadBranch("Tracks");
 105   Int_t ntr = fEsdEv->GetNumberOfTracks();
 106   for (Int_t i=0, ntrnew=0; i<ntr; ++i) {
 107     AliESDtrack *etrack = fEsdEv->GetTrack(i);
 108     if (!etrack)
 109       continue;
 110     if (!fEsdTrackCuts->AcceptTrack(etrack))
 111       continue;
 112
 113     AliESDtrack *ntrack = AliESDtrackCuts::GetTPCOnlyTrack(fEsdEv,etrack->GetID());
 114     if (!ntrack)
 115       continue;
 116     if (ntrack->Pt()<=0) {
 117       delete ntrack;
 118       continue;
 119     }
 120
 121     Double_t bfield[3] = {0,0,0};
 122     ntrack->GetBxByBz(bfield);
 123     AliExternalTrackParam exParam;
 124     Bool_t relate = ntrack->RelateToVertexBxByBz(vtxSPD,bfield,kVeryBig,&exParam);
 125     if (!relate) {
 126       delete ntrack;
 127       continue;
 128     }
 129
 130     // set the constraint parameters to the track
 131     ntrack->Set(exParam.GetX(),exParam.GetAlpha(),exParam.GetParameter(),exParam.GetCovariance());
 132
 133     if (ntrack->Pt()<=0) {
 134       delete ntrack;
 135       continue;
 136     }
 137
 138     new ((*fTracks)[ntrnew++]) AliESDtrack(*ntrack);
 139     delete ntrack;
 140   }
 141 }