PWG/Tools/AliHelperPID.cxx

   1
   2 /**************************************************************************
   3  * Copyright(c) 1998-2009, ALICE Experiment at CERN, All rights reserved. *
   4  *                                                                        *
   5  * Author: The ALICE Off-line Project.                                    *
   6  * Contributors are mentioned in the code where appropriate.              *
   7  *                                                                        *
   8  * Permission to use, copy, modify and distribute this software and its   *
   9  * documentation strictly for non-commercial purposes is hereby granted   *
  10  * without fee, provided that the above copyright notice appears in all   *
  11  * copies and that both the copyright notice and this permission notice   *
  12  * appear in the supporting documentation. The authors make no claims     *
  13  * about the suitability of this software for any purpose. It is          *
  14  * provided "as is" without express or implied warranty.                  *
  15  **************************************************************************/
  16
  17 //-----------------------------------------------------------------
  18 //         AliHelperPID class
  19 //-----------------------------------------------------------------
  20
  21 #include "AliHelperPID.h"
  22 #include "AliVEvent.h"
  23 #include "AliAODEvent.h"
  24 #include "AliMCEvent.h"
  25 #include "AliMCEventHandler.h"
  26 #include "TH1F.h"
  27 #include "TH2F.h"
  28 #include "TList.h"
  29 #include "AliStack.h"
  30 #include "AliVTrack.h"
  31 #include "TParticle.h"
  32 #include "AliAODMCParticle.h"
  33 #include "AliPIDResponse.h"
  34 #include "AliPIDCombined.h"
  35 #include "AliAnalysisManager.h"
  36 #include "AliInputEventHandler.h"
  37
  38 using namespace AliHelperPIDNameSpace;
  39 using namespace std;
  40
  41 const char * kPIDTypeName[]={"TPC","TOF","TPC-TOF"} ;
  42 const char * kDetectorName[]={"ITS","TPC","TOF"} ;
  43 const char * kParticleSpeciesName[]={"Pions","Kaons","Protons","Undefined"} ;
  44
  45 ClassImp(AliHelperPID)
  46
  47 AliHelperPID::AliHelperPID() : TNamed("HelperPID", "PID object"),fisMC(0), fPIDType(kNSigmaTPCTOF), fNSigmaPID(3), fBayesCut(0.8), fPIDResponse(0), fPIDCombined(0),fOutputList(0),fRequestTOFPID(1),fRemoveTracksT0Fill(0),fUseExclusiveNSigma(0),fPtTOFPID(.6),fHasTOFPID(0){
  48
  49   for(Int_t ipart=0;ipart<kNSpecies;ipart++)
  50     for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++)
  51       fnsigmas[ipart][ipid]=999.;
  52
  53   for(Int_t ipart=0;ipart<kNSpecies;ipart++)fHasDoubleCounting[ipart]=kFALSE;
  54
  55   fOutputList = new TList;
  56   fOutputList->SetOwner();
  57   fOutputList->SetName("OutputList");
  58
  59   //nsigma plot
  60   for(Int_t ipart=0;ipart<kNSpecies;ipart++){
  61     for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
  62       Double_t miny=-30;
  63       Double_t maxy=30;
  64       if(ipid==kNSigmaTPCTOF){miny=0;maxy=50;}
  65       TH2F *fHistoNSigma=new TH2F(Form("NSigma_%d_%d",ipart,ipid),Form("n#sigma %s %s",kParticleSpeciesName[ipart],kPIDTypeName[ipid]),200,0,10,500,miny,maxy);
  66       fHistoNSigma->GetXaxis()->SetTitle("P_{T} (GeV / c)");
  67       fHistoNSigma->GetYaxis()->SetTitle(Form("n#sigma %s %s",kParticleSpeciesName[ipart],kPIDTypeName[ipid]));
  68       fOutputList->Add(fHistoNSigma);
  69     }
  70   }
  71
  72   //nsigmaRec plot
  73   for(Int_t ipart=0;ipart<kNSpecies;ipart++){
  74     for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
  75       Double_t miny=-10;
  76       Double_t maxy=10;
  77       if(ipid==kNSigmaTPCTOF){miny=0;maxy=20;}
  78       TH2F *fHistoNSigma=new TH2F(Form("NSigmaRec_%d_%d",ipart,ipid),
  79                                   Form("n#sigma for reconstructed %s %s",kParticleSpeciesName[ipart],kPIDTypeName[ipid]),200,0,10,500,miny,maxy);
  80       fHistoNSigma->GetXaxis()->SetTitle("P_{T} (GeV / c)");
  81       fHistoNSigma->GetYaxis()->SetTitle(Form("n#sigma %s %s",kParticleSpeciesName[ipart],kPIDTypeName[ipid]));
  82       fOutputList->Add(fHistoNSigma);
  83     }
  84   }
  85
  86   //BayesRec plot
  87   for(Int_t ipart=0;ipart<kNSpecies;ipart++){
  88     Double_t miny=0.;
  89     Double_t maxy=1;
  90     TH2F *fHistoBayes=new TH2F(Form("BayesRec_%d",ipart),
  91                                Form("probability for reconstructed %s",kParticleSpeciesName[ipart]),200,0,10,500,miny,maxy);
  92     fHistoBayes->GetXaxis()->SetTitle("P_{T} (GeV / c)");
  93     fHistoBayes->GetYaxis()->SetTitle(Form("Bayes prob %s",kParticleSpeciesName[ipart]));
  94     fOutputList->Add(fHistoBayes);
  95   }
  96
  97   //nsigmaDC plot
  98   for(Int_t ipart=0;ipart<kNSpecies;ipart++){
  99     for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 100       Double_t miny=-10;
 101       Double_t maxy=10;
 102       if(ipid==kNSigmaTPCTOF){miny=0;maxy=20;}
 103       TH2F *fHistoNSigma=new TH2F(Form("NSigmaDC_%d_%d",ipart,ipid),
 104                                   Form("n#sigma for double counting %s %s",kParticleSpeciesName[ipart],kPIDTypeName[ipid]),200,0,10,500,miny,maxy);
 105       fHistoNSigma->GetXaxis()->SetTitle("P_{T} (GeV / c)");
 106       fHistoNSigma->GetYaxis()->SetTitle(Form("n#sigma %s %s",kParticleSpeciesName[ipart],kPIDTypeName[ipid]));
 107       fOutputList->Add(fHistoNSigma);
 108     }
 109   }
 110
 111   //nsigmaMC plot
 112   for(Int_t ipart=0;ipart<kNSpecies;ipart++){
 113     for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 114       Double_t miny=-30;
 115       Double_t maxy=30;
 116       if(ipid==kNSigmaTPCTOF){miny=0;maxy=50;}
 117       TH2F *fHistoNSigma=new TH2F(Form("NSigmaMC_%d_%d",ipart,ipid),
 118                                   Form("n#sigma for MC %s %s",kParticleSpeciesName[ipart],kPIDTypeName[ipid]),200,0,10,500,miny,maxy);
 119       fHistoNSigma->GetXaxis()->SetTitle("P_{T} (GeV / c)");
 120       fHistoNSigma->GetYaxis()->SetTitle(Form("n#sigma %s %s",kParticleSpeciesName[ipart],kPIDTypeName[ipid]));
 121       fOutputList->Add(fHistoNSigma);
 122     }
 123   }
 124
 125   //PID signal plot
 126   for(Int_t idet=0;idet<kNDetectors;idet++){
 127     for(Int_t ipart=0;ipart<kNSpecies;ipart++){
 128       Double_t maxy=500;
 129       if(idet==kTOF)maxy=1.1;
 130       TH2F *fHistoPID=new TH2F(Form("PID_%d_%d",idet,ipart),Form("%s signal - %s",kDetectorName[idet],kParticleSpeciesName[ipart]),200,0,10,500,-maxy,maxy);
 131       fHistoPID->GetXaxis()->SetTitle("P (GeV / c)");
 132       fHistoPID->GetYaxis()->SetTitle(Form("%s signal",kDetectorName[idet]));
 133       fOutputList->Add(fHistoPID);
 134     }
 135   }
 136   //PID signal plot, before PID cut
 137   for(Int_t idet=0;idet<kNDetectors;idet++){
 138     Double_t maxy=500;
 139     if(idet==kTOF)maxy=1.1;
 140     TH2F *fHistoPID=new TH2F(Form("PIDAll_%d",idet),Form("%s signal",kDetectorName[idet]),200,0,10,500,-maxy,maxy);
 141     fHistoPID->GetXaxis()->SetTitle("P (GeV / c)");
 142     fHistoPID->GetYaxis()->SetTitle(Form("%s signal",kDetectorName[idet]));
 143     fOutputList->Add(fHistoPID);
 144   }
 145
 146 }
 147
 148 //////////////////////////////////////////////////////////////////////////////////////////////////
 149
 150 TH2F* AliHelperPID::GetHistogram2D(const char * name){
 151   // returns histo named name
 152   return (TH2F*) fOutputList->FindObject(name);
 153 }
 154
 155 //////////////////////////////////////////////////////////////////////////////////////////////////
 156
 157 Int_t AliHelperPID::GetParticleSpecies(AliVTrack * trk, Bool_t FIllQAHistos){
 158   //return the specie according to the minimum nsigma value
 159   //no double counting, this has to be evaluated using CheckDoubleCounting()
 160
 161   Int_t ID=kSpUndefined;
 162
 163   //get the PID response
 164   if(!fPIDResponse) {
 165     AliAnalysisManager *man = AliAnalysisManager::GetAnalysisManager();
 166     AliInputEventHandler* inputHandler = (AliInputEventHandler*)(man->GetInputEventHandler());
 167     fPIDResponse = inputHandler->GetPIDResponse();
 168   }
 169   if(!fPIDResponse) {
 170     AliFatal("Cannot get pid response");
 171   }
 172
 173   //calculate nsigmas (used also by the bayesian)
 174   CalculateNSigmas(trk,FIllQAHistos);//fill the data member fnsigmas with the nsigmas value [ipart][iPID]
 175
 176   //Do PID
 177   if(fPIDType==kBayes){//use bayesianPID
 178
 179     if(!fPIDCombined) {
 180       AliFatal("PIDCombined object has to be set in the steering macro");
 181     }
 182
 183     ID = GetIDBayes(trk,FIllQAHistos);
 184
 185   }else{ //use nsigma PID
 186
 187     ID=FindMinNSigma(trk,FIllQAHistos);
 188
 189     if(fUseExclusiveNSigma){ //if one particle has double counting and exclusive nsigma is requested ID = kSpUndefined
 190       Bool_t *HasDC;
 191       HasDC=GetDoubleCounting(trk,FIllQAHistos);
 192       for(Int_t ipart=0;ipart<kNSpecies;ipart++){
 193         if(HasDC[ipart]==kTRUE)  ID = kSpUndefined;
 194       }
 195     }
 196   }
 197
 198   //Fill PID signal plot
 199   if(ID != kSpUndefined){
 200     for(Int_t idet=0;idet<kNDetectors;idet++){
 201       TH2F *h=GetHistogram2D(Form("PID_%d_%d",idet,ID));
 202       if(idet==kITS)h->Fill(trk->P(),trk->GetITSsignal()*trk->Charge());
 203       if(idet==kTPC)h->Fill(trk->P(),trk->GetTPCsignal()*trk->Charge());
 204       if(idet==kTOF && fHasTOFPID)h->Fill(trk->P(),TOFBetaCalc(trk)*trk->Charge());
 205     }
 206   }
 207   //Fill PID signal plot without cuts
 208   for(Int_t idet=0;idet<kNDetectors;idet++){
 209     TH2F *h=GetHistogram2D(Form("PIDAll_%d",idet));
 210     if(idet==kITS)h->Fill(trk->P(),trk->GetITSsignal()*trk->Charge());
 211     if(idet==kTPC)h->Fill(trk->P(),trk->GetTPCsignal()*trk->Charge());
 212     if(idet==kTOF && fHasTOFPID)h->Fill(trk->P(),TOFBetaCalc(trk)*trk->Charge());
 213   }
 214
 215   return ID;
 216 }
 217
 218 //////////////////////////////////////////////////////////////////////////////////////////////////
 219
 220 Int_t AliHelperPID::GetParticleSpecies(AliVParticle * part) {
 221   // return PID according to MC truth
 222   switch(TMath::Abs(part->PdgCode())){
 223   case 2212:
 224     return kSpProton;
 225     break;
 226   case 321:
 227     return kSpKaon;
 228     break;
 229   case 211:
 230     return kSpPion;
 231     break;
 232   default:
 233     return kSpUndefined;
 234   }
 235 }
 236
 237 //////////////////////////////////////////////////////////////////////////////////////////////////
 238
 239 Int_t AliHelperPID::GetIDBayes(AliVTrack * trk, Bool_t FIllQAHistos){
 240
 241   Bool_t *IDs=GetAllCompatibleIdentitiesNSigma(trk,FIllQAHistos);
 242
 243   Double_t probBayes[AliPID::kSPECIES];
 244
 245   UInt_t detUsed= 0;
 246   CheckTOF(trk);
 247   if(fHasTOFPID && trk->Pt()>fPtTOFPID){//use TOF information
 248     detUsed = CalcPIDCombined(trk, fPIDResponse, AliPIDResponse::kDetTOF|AliPIDResponse::kDetTPC, probBayes);
 249     if(detUsed != (AliPIDResponse::kDetTOF|AliPIDResponse::kDetTPC))return kSpUndefined;//check that TPC and TOF are used
 250   }else{
 251     detUsed = CalcPIDCombined(trk, fPIDResponse,AliPIDResponse::kDetTPC, probBayes);
 252     if(detUsed != AliPIDResponse::kDetTPC)return kSpUndefined;//check that TPC is used
 253   }
 254
 255   //the probability has to be normalized to one, we check it
 256   Double_t sump=0.;
 257   for(Int_t ipart=0;ipart<AliPID::kSPECIES;ipart++)sump+=probBayes[ipart];
 258   if(sump<.99 && sump>1.01){//FIXME precision problem in the sum, workaround
 259     AliFatal("Bayesian probability not normalized to one");
 260   }
 261
 262   //probabilities are normalized to one, if the cut is above .5 there is no problem
 263   if(probBayes[AliPID::kPion]>fBayesCut && IDs[kSpPion]==1){
 264     TH2F *h=GetHistogram2D(Form("BayesRec_%d",kSpPion));
 265     h->Fill(trk->Pt(),probBayes[AliPID::kPion]);
 266     return kSpPion;
 267   }
 268   else if(probBayes[AliPID::kKaon]>fBayesCut && IDs[kSpKaon]==1){
 269     TH2F *h=GetHistogram2D(Form("BayesRec_%d",kSpKaon));
 270     h->Fill(trk->Pt(),probBayes[AliPID::kKaon]);
 271     return kSpKaon;
 272   }
 273   else if(probBayes[AliPID::kProton]>fBayesCut && IDs[kSpProton]==1){
 274     TH2F *h=GetHistogram2D(Form("BayesRec_%d",kSpProton));
 275     h->Fill(trk->Pt(),probBayes[AliPID::kProton]);
 276     return kSpProton;
 277   }
 278   else{
 279     return kSpUndefined;
 280   }
 281 }
 282
 283 //////////////////////////////////////////////////////////////////////////////////////////////////
 284
 285 UInt_t AliHelperPID::CalcPIDCombined(const AliVTrack *track,const AliPIDResponse *PIDResponse, Int_t detMask, Double_t* prob) const{
 286   //
 287   // Bayesian PID calculation
 288   //
 289   for(Int_t i=0;i<AliPID::kSPECIES;i++)
 290     {
 291       prob[i]=0.;
 292     }
 293   fPIDCombined->SetDetectorMask(detMask);
 294
 295   return fPIDCombined->ComputeProbabilities((AliVTrack*)track, PIDResponse, prob);
 296 }
 297
 298 //////////////////////////////////////////////////////////////////////////////////////////////////
 299
 300 void AliHelperPID::CalculateNSigmas(AliVTrack * trk, Bool_t FIllQAHistos){
 301   //defines data member fnsigmas
 302
 303   // Compute nsigma for each hypthesis
 304   AliVParticle *inEvHMain = dynamic_cast<AliVParticle *>(trk);
 305   // --- TPC
 306   Double_t nsigmaTPCkProton = fPIDResponse->NumberOfSigmasTPC(inEvHMain, AliPID::kProton);
 307   Double_t nsigmaTPCkKaon   = fPIDResponse->NumberOfSigmasTPC(inEvHMain, AliPID::kKaon);
 308   Double_t nsigmaTPCkPion   = fPIDResponse->NumberOfSigmasTPC(inEvHMain, AliPID::kPion);
 309   // --- TOF
 310   Double_t nsigmaTOFkProton=999.,nsigmaTOFkKaon=999.,nsigmaTOFkPion=999.;
 311   Double_t nsigmaTPCTOFkProton=999.,nsigmaTPCTOFkKaon=999.,nsigmaTPCTOFkPion=999.;
 312
 313   CheckTOF(trk);
 314
 315   if(fHasTOFPID && trk->Pt()>fPtTOFPID){//use TOF information
 316     nsigmaTOFkProton = fPIDResponse->NumberOfSigmasTOF(inEvHMain, AliPID::kProton);
 317     nsigmaTOFkKaon   = fPIDResponse->NumberOfSigmasTOF(inEvHMain, AliPID::kKaon);
 318     nsigmaTOFkPion   = fPIDResponse->NumberOfSigmasTOF(inEvHMain, AliPID::kPion);
 319     Double_t d2Proton=nsigmaTPCkProton * nsigmaTPCkProton + nsigmaTOFkProton * nsigmaTOFkProton;
 320     Double_t d2Kaon=nsigmaTPCkKaon * nsigmaTPCkKaon + nsigmaTOFkKaon * nsigmaTOFkKaon;
 321     Double_t d2Pion=nsigmaTPCkPion * nsigmaTPCkPion + nsigmaTOFkPion * nsigmaTOFkPion;
 322     //commented, this is done in analogy with AliESDTrackCuts, nsigma combind according to the probability
 323     // --- combined
 324     // -----------------------------------
 325     // How to get to a n-sigma cut?
 326     //
 327     // The accumulated statistics from 0 to d is
 328     //
 329     // ->  Erf(d/Sqrt(2)) for a 1-dim gauss (d = n_sigma)
 330     // ->  1 - Exp(-d**2) for a 2-dim gauss (d*d = dx*dx + dy*dy != n_sigma)
 331     // It means that for a 2-dim gauss: n_sigma(d) = Sqrt(2)*ErfInv(1 - Exp((-d**2)/2)
 332     //
 333     // work around precision problem
 334     // if d is too big, TMath::Exp(...) gets 0, and TMath::ErfInverse(1) that should be infinite, gets 0 :(
 335     //if(TMath::Exp(- d2Proton / 2) > 1e-15)nsigmaTPCTOFkProton  =  TMath::Sqrt(2)*TMath::ErfInverse(1 - TMath::Exp(- d2Proton / 2));
 336     //if(TMath::Exp(- d2Kaon / 2) > 1e-15)nsigmaTPCTOFkKaon    = TMath::Sqrt(2)*TMath::ErfInverse(1 - TMath::Exp(- d2Kaon / 2));
 337     //if(TMath::Exp(- d2Pion / 2) > 1e-15)nsigmaTPCTOFkPion     = TMath::Sqrt(2)*TMath::ErfInverse(1 - TMath::Exp(- d2Pion / 2));
 338
 339     //used for the 2PC PID paper (circular cut)
 340     nsigmaTPCTOFkProton  =  TMath::Sqrt(d2Proton);
 341     nsigmaTPCTOFkKaon    =  TMath::Sqrt(d2Kaon);
 342     nsigmaTPCTOFkPion    =  TMath::Sqrt(d2Pion);
 343   }else{
 344     // --- combined
 345     // if TOF is missing and below fPtTOFPID only the TPC information is used
 346     nsigmaTPCTOFkProton = TMath::Abs(nsigmaTPCkProton);
 347     nsigmaTPCTOFkKaon   = TMath::Abs(nsigmaTPCkKaon);
 348     nsigmaTPCTOFkPion   = TMath::Abs(nsigmaTPCkPion);
 349   }
 350
 351   //set data member fnsigmas
 352   fnsigmas[kSpPion][kNSigmaTPC]=nsigmaTPCkPion;
 353   fnsigmas[kSpKaon][kNSigmaTPC]=nsigmaTPCkKaon;
 354   fnsigmas[kSpProton][kNSigmaTPC]=nsigmaTPCkProton;
 355   fnsigmas[kSpPion][kNSigmaTOF]=nsigmaTOFkPion;
 356   fnsigmas[kSpKaon][kNSigmaTOF]=nsigmaTOFkKaon;
 357   fnsigmas[kSpProton][kNSigmaTOF]=nsigmaTOFkProton;
 358   fnsigmas[kSpPion][kNSigmaTPCTOF]=nsigmaTPCTOFkPion;
 359   fnsigmas[kSpKaon][kNSigmaTPCTOF]=nsigmaTPCTOFkKaon;
 360   fnsigmas[kSpProton][kNSigmaTPCTOF]=nsigmaTPCTOFkProton;
 361
 362   if(FIllQAHistos){
 363     //Fill NSigma SeparationPlot
 364     for(Int_t ipart=0;ipart<kNSpecies;ipart++){
 365       for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 366         if((ipid!=kNSigmaTPC) && (!fHasTOFPID) && trk->Pt()<fPtTOFPID)continue;//not filling TOF and combined if no TOF PID
 367         TH2F *h=GetHistogram2D(Form("NSigma_%d_%d",ipart,ipid));
 368         h->Fill(trk->Pt(),fnsigmas[ipart][ipid]);
 369       }
 370     }
 371   }
 372 }
 373
 374 //////////////////////////////////////////////////////////////////////////////////////////////////
 375
 376 Int_t AliHelperPID::FindMinNSigma(AliVTrack * trk,Bool_t FillQAHistos){
 377
 378   CheckTOF(trk);
 379   if(fRequestTOFPID && (!fHasTOFPID) && trk->Pt()>fPtTOFPID)return kSpUndefined;
 380
 381   //get the identity of the particle with the minimum Nsigma
 382   Double_t nsigmaPion=999., nsigmaKaon=999., nsigmaProton=999.;
 383   switch (fPIDType){
 384   case kNSigmaTPC:
 385     nsigmaProton  =  TMath::Abs(fnsigmas[kSpProton][kNSigmaTPC]);
 386     nsigmaKaon    =  TMath::Abs(fnsigmas[kSpKaon][kNSigmaTPC])  ;
 387     nsigmaPion    =  TMath::Abs(fnsigmas[kSpPion][kNSigmaTPC])  ;
 388     break;
 389   case kNSigmaTOF:
 390     nsigmaProton  =  TMath::Abs(fnsigmas[kSpProton][kNSigmaTOF]);
 391     nsigmaKaon    =  TMath::Abs(fnsigmas[kSpKaon][kNSigmaTOF])  ;
 392     nsigmaPion    =  TMath::Abs(fnsigmas[kSpPion][kNSigmaTOF])  ;
 393     break;
 394   case kNSigmaTPCTOF://In case of no TOF matching the combined nsigma is the TPC one
 395     nsigmaProton  =  TMath::Abs(fnsigmas[kSpProton][kNSigmaTPCTOF]);
 396     nsigmaKaon    =  TMath::Abs(fnsigmas[kSpKaon][kNSigmaTPCTOF])  ;
 397     nsigmaPion    =  TMath::Abs(fnsigmas[kSpPion][kNSigmaTPCTOF])  ;
 398     break;
 399   case kBayes://the nsigma in the bayesian is used to clean with a very large n-sigma value
 400     nsigmaProton  =  TMath::Abs(fnsigmas[kSpProton][kNSigmaTPCTOF]);
 401     nsigmaKaon    =  TMath::Abs(fnsigmas[kSpKaon][kNSigmaTPCTOF])  ;
 402     nsigmaPion    =  TMath::Abs(fnsigmas[kSpPion][kNSigmaTPCTOF])  ;
 403     break;
 404   }
 405
 406   // guess the particle based on the smaller nsigma (within fNSigmaPID)
 407   if( ( nsigmaKaon==nsigmaPion ) && ( nsigmaKaon==nsigmaProton )) return kSpUndefined;//if is the default value for the three
 408
 409   if( ( nsigmaKaon   < nsigmaPion ) && ( nsigmaKaon < nsigmaProton ) && (nsigmaKaon   < fNSigmaPID)){
 410     if(FillQAHistos){
 411       for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 412         if((ipid!=kNSigmaTPC) && (!fHasTOFPID) && (trk->Pt()<fPtTOFPID))continue;//not filling TOF and combined if no TOF PID
 413         TH2F *h=GetHistogram2D(Form("NSigmaRec_%d_%d",kSpKaon,ipid));
 414         h->Fill(trk->Pt(),fnsigmas[kSpKaon][ipid]);
 415       }
 416     }
 417     return kSpKaon;
 418   }
 419   if( ( nsigmaPion   < nsigmaKaon ) && ( nsigmaPion < nsigmaProton ) && (nsigmaPion   < fNSigmaPID)){
 420     if(FillQAHistos){
 421       for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 422         if((ipid!=kNSigmaTPC) && (!fHasTOFPID) && (trk->Pt()<fPtTOFPID))continue;//not filling TOF and combined if no TOF PID
 423         TH2F *h=GetHistogram2D(Form("NSigmaRec_%d_%d",kSpPion,ipid));
 424         h->Fill(trk->Pt(),fnsigmas[kSpPion][ipid]);
 425       }
 426     }
 427     return kSpPion;
 428   }
 429   if( ( nsigmaProton < nsigmaKaon ) && ( nsigmaProton < nsigmaPion ) && (nsigmaProton < fNSigmaPID)){
 430     if(FillQAHistos){
 431       for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 432         if((ipid!=kNSigmaTPC) && (!fHasTOFPID) && (trk->Pt()<fPtTOFPID))continue;//not filling TOF and combined if no TOF PID
 433         TH2F *h=GetHistogram2D(Form("NSigmaRec_%d_%d",kSpProton,ipid));
 434         h->Fill(trk->Pt(),fnsigmas[kSpProton][ipid]);
 435       }
 436     }
 437     return kSpProton;
 438   }
 439   // else, return undefined
 440   return kSpUndefined;
 441 }
 442
 443 //////////////////////////////////////////////////////////////////////////////////////////////////
 444
 445 Bool_t* AliHelperPID::GetDoubleCounting(AliVTrack * trk,Bool_t FIllQAHistos){
 446   //if a particle has double counting set fHasDoubleCounting[ipart]=kTRUE
 447   //fill DC histos
 448   for(Int_t ipart=0;ipart<kNSpecies;ipart++)fHasDoubleCounting[ipart]=kFALSE;//array with kTRUE for second (or third) identity of the track
 449
 450   Int_t MinNSigma=FindMinNSigma(trk,kFALSE);//not filling the NSigmaRec histos
 451
 452   CheckTOF(trk);
 453
 454   if(MinNSigma==kSpUndefined)return fHasDoubleCounting;//in case of undefined no Double counting
 455
 456   Double_t nsigmaPion=999., nsigmaKaon=999., nsigmaProton=999.;
 457   switch (fPIDType) {
 458   case kNSigmaTPC:
 459     nsigmaProton  =  TMath::Abs(fnsigmas[kSpProton][kNSigmaTPC]);
 460     nsigmaKaon    =  TMath::Abs(fnsigmas[kSpKaon][kNSigmaTPC])  ;
 461     nsigmaPion    =  TMath::Abs(fnsigmas[kSpPion][kNSigmaTPC])  ;
 462     break;
 463   case kNSigmaTOF:
 464     nsigmaProton  =  TMath::Abs(fnsigmas[kSpProton][kNSigmaTOF]);
 465     nsigmaKaon    =  TMath::Abs(fnsigmas[kSpKaon][kNSigmaTOF])  ;
 466     nsigmaPion    =  TMath::Abs(fnsigmas[kSpPion][kNSigmaTOF])  ;
 467     break;
 468   case kNSigmaTPCTOF://In case of no TOF matching the combined nsigma is the TPC one
 469     nsigmaProton  =  TMath::Abs(fnsigmas[kSpProton][kNSigmaTPCTOF]);
 470     nsigmaKaon    =  TMath::Abs(fnsigmas[kSpKaon][kNSigmaTPCTOF])  ;
 471     nsigmaPion    =  TMath::Abs(fnsigmas[kSpPion][kNSigmaTPCTOF])  ;
 472     break;
 473   case kBayes://the nsigma in the bayesian is used to clean with a very large n-sigma value
 474     nsigmaProton  =  TMath::Abs(fnsigmas[kSpProton][kNSigmaTPCTOF]);
 475     nsigmaKaon    =  TMath::Abs(fnsigmas[kSpKaon][kNSigmaTPCTOF])  ;
 476     nsigmaPion    =  TMath::Abs(fnsigmas[kSpPion][kNSigmaTPCTOF])  ;
 477     break;
 478   }
 479   if(nsigmaPion<fNSigmaPID && MinNSigma!=kSpPion)fHasDoubleCounting[kSpPion]=kTRUE;
 480   if(nsigmaKaon<fNSigmaPID && MinNSigma!=kSpKaon)fHasDoubleCounting[kSpKaon]=kTRUE;
 481   if(nsigmaProton<fNSigmaPID && MinNSigma!=kSpProton)fHasDoubleCounting[kSpProton]=kTRUE;
 482
 483   if(FIllQAHistos){
 484     //fill NSigma distr for double counting
 485     for(Int_t ipart=0;ipart<kNSpecies;ipart++){
 486       if(fHasDoubleCounting[ipart]){
 487         for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 488           if((ipid!=kNSigmaTPC) && (!fHasTOFPID) && (trk->Pt()<fPtTOFPID))continue;//not filling TOF and combined if no TOF PID
 489           TH2F *h=GetHistogram2D(Form("NSigmaDC_%d_%d",ipart,ipid));
 490           h->Fill(trk->Pt(),fnsigmas[ipart][ipid]);
 491         }
 492       }
 493     }
 494   }
 495   return fHasDoubleCounting;
 496 }
 497
 498 //////////////////////////////////////////////////////////////////////////////////////////////////
 499
 500 Bool_t* AliHelperPID::GetAllCompatibleIdentitiesNSigma(AliVTrack * trk,Bool_t FIllQAHistos){
 501
 502   Bool_t *IDs=GetDoubleCounting(trk,FIllQAHistos);
 503   IDs[FindMinNSigma(trk,FIllQAHistos)]=kTRUE;
 504   return IDs;
 505
 506 }
 507
 508 //////////////////////////////////////////////////////////////////////////////////////////////////
 509
 510 Int_t AliHelperPID::GetMCParticleSpecie(AliVEvent* event, AliVTrack * trk, Bool_t FillQAHistos){
 511   //return the specie according to the MC truth
 512   CheckTOF(trk);
 513
 514   if(!fisMC)AliFatal("Error: AliHelperPID::GetMCParticleSpecie called on data\n");
 515
 516   Int_t code=999;
 517   Bool_t isAOD=kFALSE;
 518   Bool_t isESD=kFALSE;
 519   TString nameoftrack(event->ClassName());
 520   if(!nameoftrack.CompareTo("AliESDEvent"))isESD=kTRUE;
 521   else if(!nameoftrack.CompareTo("AliAODEvent"))isAOD=kTRUE;
 522   else AliFatal("Not processing AODs nor ESDs") ;
 523
 524   if(isAOD){
 525     TClonesArray *arrayMC = 0;
 526     arrayMC = (TClonesArray*) event->GetList()->FindObject(AliAODMCParticle::StdBranchName());
 527     if (!arrayMC)AliFatal("Error: MC particles branch not found!\n");
 528     AliAODMCParticle *partMC = (AliAODMCParticle*) arrayMC->At(TMath::Abs(trk->GetLabel()));
 529     if (!partMC){
 530       AliError("Cannot get MC particle");
 531       return kSpUndefined;
 532     }
 533     code=partMC->GetPdgCode();
 534   }
 535   if(isESD){
 536     AliStack* stack=0x0;
 537     AliMCEventHandler* eventHandler = dynamic_cast<AliMCEventHandler*> (AliAnalysisManager::GetAnalysisManager()->GetMCtruthEventHandler());
 538     if (!eventHandler) AliFatal("ERROR: Could not retrieve MC event handler");
 539     AliMCEvent* mcEvent = eventHandler->MCEvent();
 540     if (!mcEvent)AliFatal("ERROR: Could not retrieve MC event");
 541     stack = mcEvent->Stack();
 542     if (!stack) AliFatal("ERROR: stack not available\n");
 543     TParticle *part=0;
 544     part = (TParticle*)stack->Particle(TMath::Abs(trk->GetLabel()));
 545     if (!part){
 546       AliError("Cannot get MC particle");
 547       return kSpUndefined;
 548     }
 549     code = part->GetPdgCode();
 550   }
 551   switch(TMath::Abs(code)){
 552   case 2212:
 553     if(FillQAHistos){
 554       for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 555         if((ipid!=kNSigmaTPC) && (!fHasTOFPID) && (trk->Pt()<fPtTOFPID))continue;//not filling TOF and combined if no TOF PID
 556         TH2F *h=GetHistogram2D(Form("NSigmaMC_%d_%d",kSpProton,ipid));
 557         h->Fill(trk->Pt(),fnsigmas[kSpProton][ipid]);
 558       }
 559     }
 560     return kSpProton;
 561     break;
 562   case 321:
 563     if(FillQAHistos){
 564       for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 565         if((ipid!=kNSigmaTPC) && (!fHasTOFPID) && (trk->Pt()<fPtTOFPID))continue;//not filling TOF and combined if no TOF PID
 566         TH2F *h=GetHistogram2D(Form("NSigmaMC_%d_%d",kSpKaon,ipid));
 567         h->Fill(trk->Pt(),fnsigmas[kSpKaon][ipid]);
 568       }
 569     }
 570     return kSpKaon;
 571     break;
 572   case 211:
 573     if(FillQAHistos){
 574       for(Int_t ipid=0;ipid<=kNSigmaPIDType;ipid++){
 575         if((ipid!=kNSigmaTPC) && (!fHasTOFPID) && (trk->Pt()<fPtTOFPID))continue;//not filling TOF and combined if no TOF PID
 576         TH2F *h=GetHistogram2D(Form("NSigmaMC_%d_%d",kSpPion,ipid));
 577         h->Fill(trk->Pt(),fnsigmas[kSpPion][ipid]);
 578       }
 579     }
 580     return kSpPion;
 581     break;
 582   default:
 583     return kSpUndefined;
 584   }
 585
 586 }
 587
 588 //////////////////////////////////////////////////////////////////////////////////////////////////
 589
 590 void AliHelperPID::CheckTOF(AliVTrack * trk)
 591 {
 592   //check if the particle has TOF Matching
 593
 594   //get the PIDResponse
 595   if(fPIDResponse->CheckPIDStatus(AliPIDResponse::kTOF,trk)==0)fHasTOFPID=kFALSE;
 596   else fHasTOFPID=kTRUE;
 597
 598   //in addition to TOF status we look at the pt
 599   if(trk->Pt()<fPtTOFPID)fHasTOFPID=kFALSE;
 600
 601   if(fRemoveTracksT0Fill)
 602     {
 603       Int_t startTimeMask = fPIDResponse->GetTOFResponse().GetStartTimeMask(trk->P());
 604       if (startTimeMask < 0)fHasTOFPID=kFALSE;
 605     }
 606 }
 607
 608 //////////////////////////////////////////////////////////////////////////////////////////////////
 609
 610 Double_t AliHelperPID::TOFBetaCalc(AliVTrack *track) const{
 611   //TOF beta calculation
 612   Double_t tofTime=track->GetTOFsignal();
 613
 614   Double_t c=TMath::C()*1.E-9;// m/ns
 615   Float_t startTime = fPIDResponse->GetTOFResponse().GetStartTime(((AliVTrack*)track)->P());//in ps
 616   Double_t length= fPIDResponse->GetTOFResponse().GetExpectedSignal(track,AliPID::kElectron)*1E-3*c;
 617   tofTime -= startTime;      // subtract startTime to the signal
 618   Double_t tof= tofTime*1E-3; // ns, average T0 fill subtracted, no info from T0detector
 619   tof=tof*c;
 620   return length/tof;
 621 }
 622
 623 //////////////////////////////////////////////////////////////////////////////////////////////////
 624
 625 Double_t AliHelperPID::GetMass(AliHelperParticleSpecies_t id) const{
 626   //return Mass according to AliHelperParticleSpecies_t. If undefined return -999.
 627   Double_t mass=-999.;
 628   if (id == kSpProton) { mass=9.38271999999999995e-01; }
 629   if (id == kSpKaon)   { mass=4.93676999999999977e-01; }
 630   if (id == kSpPion)    { mass=1.39570000000000000e-01; }
 631   return mass;
 632 }
 633
 634 //////////////////////////////////////////////////////////////////////////////////////////////////
 635
 636 Long64_t AliHelperPID::Merge(TCollection* list)
 637 {
 638   // Merging interface.
 639   // Returns the number of merged objects (including this).
 640   Printf("Merging");
 641   if (!list)
 642     return 0;
 643   if (list->IsEmpty())
 644     return 1;
 645   TIterator* iter = list->MakeIterator();
 646   TObject* obj;
 647   // collections of TList with output histos
 648   TList collections;
 649   Int_t count = 0;
 650   while ((obj = iter->Next())) {
 651     AliHelperPID* entry = dynamic_cast<AliHelperPID*> (obj);
 652     if (entry == 0)
 653       continue;
 654     TList * outputlist = entry->GetOutputList();
 655     collections.Add(outputlist);
 656     count++;
 657   }
 658   fOutputList->Merge(&collections);
 659   delete iter;
 660   Printf("OK");
 661   return count+1;
 662 }