6 #include "TGraphErrors.h"
9 #include "Cal/AliTRDCalPID.h"
10 #include "AliTRDpidUtil.h"
12 ClassImp(AliTRDpidUtil)
15 Float_t AliTRDpidUtil::fEleEffi = 0.9;
17 //________________________________________________________________________
18 AliTRDpidUtil::AliTRDpidUtil()
26 // Default constructor
32 //________________________________________________________________________
33 Bool_t AliTRDpidUtil::CalculatePionEffi(TH1* histo1, TH1* histo2)
34 // Double_t AliTRDpidUtil::GetError()
37 // Calculates the pion efficiency
40 histo1 -> SetLineColor(kRed);
41 histo2 -> SetLineColor(kBlue);
42 if(!histo1 -> GetEntries() || !histo2 -> GetEntries()){
43 AliWarning("Histo with no entries !");
46 histo1 -> Scale(1./histo1->GetEntries());
47 histo2 -> Scale(1./histo2->GetEntries());
49 Int_t abinE, bbinE, cbinE = -1;
50 Double_t aBinSumE, bBinSumE; // content of a single bin
51 Bool_t bFirst = 1; // checks if threshold is crossed for the first time
52 Double_t SumElecsE[kBins+2], SumPionsE[kBins+2]; // array of the integrated sum in each bin
53 memset(SumElecsE, 0, (kBins+2)*sizeof(Double_t));
54 memset(SumPionsE, 0, (kBins+2)*sizeof(Double_t));
57 // calculate electron efficiency of each bin
58 for (abinE = (histo1 -> GetNbinsX()); abinE >= 0; abinE--){
60 aBinSumE = histo1 -> GetBinContent(abinE);
62 SumElecsE[abinE] = SumElecsE[abinE+1] + aBinSumE;
64 if((SumElecsE[abinE] >= fEleEffi) && (bFirst == 1)){
67 fCalcEleEffi = (SumElecsE[cbinE]);
71 fThreshold = histo1 -> GetBinCenter(cbinE);
73 // calculate pion efficiency of each bin
74 for (bbinE = (histo2 -> GetNbinsX()); bbinE >= abinE; bbinE--){
76 bBinSumE = histo2 -> GetBinContent(bbinE);
78 SumPionsE[bbinE] = SumPionsE[bbinE+1] + bBinSumE;
80 fPionEffi = (SumPionsE[cbinE]);
85 // pion efficiency vs electron efficiency
86 TGraph gEffis(kBins, SumElecsE, SumPionsE);
88 // use fit function to get derivate of the TGraph for error calculation
89 TF1 f1("f1","[0]*x*x+[1]*x+[2]", fEleEffi-.05, fEleEffi+.05);
90 gEffis.Fit(&f1, "Q", "", fEleEffi-.05, fEleEffi+.05);
92 // return the error of the pion efficiency
93 if(((1.-fPionEffi) < 0) || ((1.-fCalcEleEffi) < 0)){
94 AliWarning(" EleEffi or PioEffi > 1. Error can not be calculated. Please increase statistics or check your simulation!");
97 fError = sqrt(((1/histo2 -> GetEntries())*fPionEffi*(1-fPionEffi))+((f1.Derivative(fEleEffi))*(f1.Derivative(fEleEffi))*(1/histo1 -> GetEntries())*fCalcEleEffi*(1-fCalcEleEffi)));
99 // AliInfo(Form("Pion Effi at [%f] : [%f +/- %f], Threshold[%f]", fCalcEleEffi, fPionEffi, fError, fThreshold));
100 // AliInfo(Form("Derivative at %4.2f : %f\n", fEleEffi, f1.Derivative(fEleEffi)));
105 //__________________________________________________________________________
106 Int_t AliTRDpidUtil::GetMomentumBin(Double_t p)
109 // returns the momentum bin for a given momentum
112 Int_t pBin1 = -1; // check bin1
113 Int_t pBin2 = -1; // check bin2
115 if(p < 0) return -1; // return -1 if momentum < 0
116 if(p < AliTRDCalPID::GetMomentum(0)) return 0; // smallest momentum bin
117 if(p >= AliTRDCalPID::GetMomentum(AliTRDCalPID::kNMom-1)) return AliTRDCalPID::kNMom-1; // largest momentum bin
120 // calculate momentum bin for non extremal momenta
121 for(Int_t iMomBin = 1; iMomBin < AliTRDCalPID::kNMom; iMomBin++){
122 if(p < AliTRDCalPID::GetMomentum(iMomBin)){
129 if(p - AliTRDCalPID::GetMomentum(pBin1) >= AliTRDCalPID::GetMomentum(pBin2) - p){