PWG2/FLOW/AliFlowAnalysisWithMCEventPlane.cxx

   1 /*************************************************************************
   2 * Copyright(c) 1998-2008, ALICE Experiment at CERN, All rights reserved. *
   3 *                                                                        *
   4 * Author: The ALICE Off-line Project.                                    *
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   6 *                                                                        *
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  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 #define AliFlowAnalysisWithMCEventPlane_cxx
  17
  18 #include "Riostream.h"  //needed as include
  19 #include "TFile.h"      //needed as include
  20 #include "TProfile.h"   //needed as include
  21 #include "TComplex.h"   //needed as include
  22
  23 class TH1F;
  24
  25 #include "AliFlowCommonConstants.h"    //needed as include
  26 #include "AliFlowEventSimple.h"
  27 #include "AliFlowTrackSimple.h"
  28 #include "AliFlowCommonHist.h"
  29 #include "AliFlowCommonHistResults.h"
  30 #include "AliFlowAnalysisWithMCEventPlane.h"
  31
  32 class AliFlowVector;
  33
  34 // AliFlowAnalysisWithMCEventPlane:
  35 // Description: Maker to analyze Flow from the generated MC reaction plane.
  36 //              This class is used to get the real value of the flow
  37 //              to compare the other methods to when analysing simulated events
  38 // author: N. van der Kolk (kolk@nikhef.nl)
  39
  40 ClassImp(AliFlowAnalysisWithMCEventPlane)
  41
  42   //-----------------------------------------------------------------------
  43
  44  AliFlowAnalysisWithMCEventPlane::AliFlowAnalysisWithMCEventPlane():
  45    fQsum(NULL),
  46    fQ2sum(0),
  47    fEventNumber(0),
  48    fDebug(kFALSE),
  49    fHistFileName(0),
  50    fHistFile(0),
  51    fCommonHists(NULL),
  52    fCommonHistsRes(NULL),
  53    fHistProFlow(NULL),
  54    fHistRP(NULL)
  55
  56 {
  57
  58   // Constructor.
  59   fQsum = new TVector2;        // flow vector sum
  60 }
  61
  62
  63  //-----------------------------------------------------------------------
  64
  65
  66  AliFlowAnalysisWithMCEventPlane::~AliFlowAnalysisWithMCEventPlane()
  67  {
  68    //destructor
  69    delete fQsum;
  70  }
  71
  72
  73 //-----------------------------------------------------------------------
  74 void AliFlowAnalysisWithMCEventPlane::Init() {
  75
  76   //Define all histograms
  77   cout<<"---Analysis with the real MC Event Plane---"<<endl;
  78
  79   Int_t iNbinsPt = AliFlowCommonConstants::GetNbinsPt();
  80   Double_t  dPtMin = AliFlowCommonConstants::GetPtMin();
  81   Double_t  dPtMax = AliFlowCommonConstants::GetPtMax();
  82
  83   // analysis file (output)
  84   fHistFile = new TFile(fHistFileName.Data(),"RECREATE") ;
  85
  86   fCommonHists = new AliFlowCommonHist("MC");
  87   fCommonHistsRes = new AliFlowCommonHistResults("MC");
  88
  89   fHistProFlow = new TProfile("FlowPro_VPt_MC","FlowPro_VPt_MC",iNbinsPt,dPtMin,dPtMax);
  90   fHistProFlow->SetXTitle("Pt");
  91   fHistProFlow->SetYTitle("v2 (%)");
  92
  93   fHistRP = new TH1F("Flow_RP_MC","Flow_RP_MC",100,0.,3.14);
  94   fHistRP->SetXTitle("Reaction Plane Angle");
  95   fHistRP->SetYTitle("Counts");
  96
  97
  98   fEventNumber = 0;  //set number of events to zero
  99
 100 }
 101
 102 //-----------------------------------------------------------------------
 103
 104 void AliFlowAnalysisWithMCEventPlane::Make(AliFlowEventSimple* anEvent, Double_t aRP) {
 105
 106   //Calculate v2 from the MC reaction plane
 107   if (anEvent) {
 108
 109     //fill control histograms
 110     fCommonHists->FillControlHistograms(anEvent);
 111
 112     //get the Q vector from the FlowEvent
 113     AliFlowVector vQ = anEvent->GetQ();
 114     //cout<<"vQ.Mod() = " << vQ.Mod() << endl;
 115     //for chi calculation:
 116     *fQsum += vQ;
 117     //cout<<"fQsum.Mod() = "<<fQsum.Mod()<<endl;
 118     fQ2sum += vQ.Mod2();
 119     cout<<"fQ2sum = "<<fQ2sum<<endl;
 120
 121     fHistRP->Fill(aRP);
 122
 123     //calculate flow
 124     //loop over the tracks of the event
 125     Int_t iNumberOfTracks = anEvent->NumberOfTracks();
 126     for (Int_t i=0;i<iNumberOfTracks;i++)
 127       {
 128         AliFlowTrackSimple* pTrack = anEvent->GetTrack(i) ;
 129         if (pTrack){
 130           if (pTrack->UseForDifferentialFlow()) {
 131             Double_t dPhi = pTrack->Phi();
 132             //if (dPhi<0.) dPhi+=2*TMath::Pi();
 133             //calculate flow v2:
 134             Double_t dv2 = TMath::Cos(2*(dPhi-aRP));
 135             Double_t dPt = pTrack->Pt();
 136             //fill histogram
 137             fHistProFlow->Fill(dPt,100*dv2);
 138           }
 139         }//track selected
 140       }//loop over tracks
 141
 142     fEventNumber++;
 143     cout<<"@@@@@ "<<fEventNumber<<" events processed"<<endl;
 144   }
 145 }
 146
 147   //--------------------------------------------------------------------
 148 void AliFlowAnalysisWithMCEventPlane::Finish() {
 149
 150   //*************make histograms etc.
 151   if (fDebug) cout<<"AliFlowAnalysisWithMCEventPlane::Terminate()"<<endl;
 152
 153   Int_t iNbinsPt = AliFlowCommonConstants::GetNbinsPt();
 154
 155   TH1F* fHistPtDiff = fCommonHists->GetfHistPtDiff();
 156   Double_t dV = 0.;
 157   Double_t dErrV = 0.;
 158   Double_t dSum = 0.;
 159   for(Int_t b=0;b<iNbinsPt;b++){
 160     Double_t dv2pro = 0.;
 161     Double_t dErrdifcomb = 0.; //in case error from profile is correct
 162     if(fHistProFlow) {
 163       dv2pro = fHistProFlow->GetBinContent(b);
 164       dErrdifcomb = fHistProFlow->GetBinError(b);
 165       //fill TH1D
 166       fCommonHistsRes->FillDifferentialFlow(b, dv2pro, dErrdifcomb);
 167       if (fHistPtDiff){
 168         //integrated flow
 169         Double_t dYield = fHistPtDiff->GetBinContent(b);
 170         dV += dv2pro/100*dYield ;
 171         dSum += dYield;
 172         //error on integrated flow
 173         dErrV += dYield*dYield*(dErrdifcomb/100)*(dErrdifcomb/100);
 174       }
 175     }
 176   }
 177   dV /= dSum;  //because pt distribution should be normalised
 178   dErrV /= dSum*dSum;
 179   dErrV = TMath::Sqrt(dErrV);
 180   cout<<"dV is "<<dV<<" +- "<<dErrV<<endl;
 181   fCommonHistsRes->FillIntegratedFlow(dV,dErrV);
 182
 183   // write to file
 184   fHistFile->Write();
 185
 186   cout<<".....finished"<<endl;
 187  }
 188
 189