TOF/AliTOFT0.cxx

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  15
  16 //_________________________________________________________________________
  17 // This is a TTask that made the calculation of the Time zero using TOF.
  18 // Description: The algorithm used to calculate the time zero of interaction
  19 // using TOF detector is the following.
  20 // We select in the MonteCarlo some primary particles - or tracks in the following -
  21 // that strike the TOF detector (the larger part are pions, kaons or protons).
  22 // We choose a set of 10 selected tracks, for each track You have the length
  23 // of the track when the TOF is reached (a standard TOF hit does not contain this
  24 // additional information, this is the reason why we implemented a new time zero
  25 // dedicated TOF hit class AliTOFhitT0; in order to store this type of hit You
  26 // have to use the AliTOFv4T0 as TOF class in Your Config.C. In AliTOFv4T0 the
  27 // StepManager was modified in order to fill the TOF hit branch with this type
  28 // of hits; in fact the AliTOF::AddT0Hit is called rather that the usual AliTOF::AddHit),
  29 // the momentum at generation (from TreeK) and the time of flight
  30 // given by the TOF detector.
  31 // (Observe that the ctor of the AliTOF class, when the AliTOFv4T0 class is used, is called
  32 // with the "tzero" option: it is in order create the fHits TClonesArray filled with
  33 // AliTOFhitT0 objects, rather than with normal AliTOFhit)
  34 // Then Momentum and time of flight for each track are smeared according to
  35 // known experimental resolution (all sources of error have been token into account).
  36 // Let consider now only one set of 10 tracks (the algorithm is the same for all sets).
  37 // Assuming the (mass) hypothesis that each track can be AUT a pion, AUT a kaon, AUT a proton,
  38 // we consider all the 3 at 10 possible cases.
  39 // For each track in each (mass) configuration
  40 // (a configuration can be e.g. pion/pion/kaon/proton/pion/proton/kaon/kaon/pion/pion)
  41 // we calculate the time zero (we know in fact the velocity of the track after
  42 // the assumption about its mass, the time of flight given by the TOF, and the
  43 // corresponding path travelled till the TOF detector). Then for each mass configuration we have
  44 // 10 time zero and we can calculate the ChiSquare for the current configuration using the
  45 // weighted mean over all 10 time zero.
  46 // We call the best assignment the mass configuration that gives the minimum value of the ChiSquare.
  47 // We plot the weighted mean over all 10 time zero for the best assignment,
  48 // the ChiSquare for the best assignment and the corresponding confidence level.
  49 // The strong assumption is the MC selection of primary particles. It will be introduced
  50 // in the future also some more realistic simulation about this point.
  51 // Use case:
  52 // root [0] AliTOFT0 * tzero = new AliTOFT0("galice.root")
  53 // Warning in <TDatabasePDG::TDatabasePDG>: object already instantiated
  54 // root [1] tzero->ExecuteTask()
  55 // root [2] tzero->ExecuteTask("tim")
  56 //             // available parameters:
  57 //             tim - print benchmarking information
  58 //             all - print usefull informations about the number of misidentified tracks
  59 //                   and a comparison about the true configuration (known from MC) and the best
  60 //                   assignment
  61 //-- Author: F. Pierella
  62 //////////////////////////////////////////////////////////////////////////////
  63
  64 #include "AliTOFT0.h"
  65 #include "AliTOFhitT0.h"
  66 #include "AliTOF.h"
  67 #include "AliTOFv4T0.h"
  68 #include "AliRun.h"
  69 #include "AliDetector.h"
  70 #include "AliMC.h"
  71
  72 #include "TH1.h"
  73 #include "TFile.h"
  74 #include "TTask.h"
  75 #include "TTree.h"
  76 #include "TSystem.h"
  77 #include "TCanvas.h"
  78 #include "TFrame.h"
  79 #include "TROOT.h"
  80 #include "TFolder.h"
  81 #include "TBenchmark.h"
  82 #include "TParticle.h"
  83 #include "TClonesArray.h"
  84 #include <stdlib.h>
  85 #include <Riostream.h>
  86
  87 ClassImp(AliTOFT0)
  88
  89 //____________________________________________________________________________
  90   AliTOFT0::AliTOFT0():TTask("AliTOFT0","")
  91 {
  92   // ctor
  93   fNevents = 0 ;
  94 }
  95
  96 //____________________________________________________________________________
  97   AliTOFT0::AliTOFT0(char* headerFile, Int_t nEvents):TTask("AliTOFT0","")
  98 {
  99   fNevents=nEvents ; // Number of events for which calculate the T0,
 100                      // default 0: it means all evens in current file
 101   fLowerMomBound=1.5; // [GeV/c] default value
 102   fUpperMomBound=2. ; // [GeV/c] default value
 103   fTimeResolution   = 1.2e-10; // 120 ps by default
 104   fHeadersFile = headerFile ;
 105
 106   TFile * file = (TFile*) gROOT->GetFile(fHeadersFile.Data() ) ;
 107
 108   //File was not opened yet
 109   if(file == 0){
 110     if(fHeadersFile.Contains("rfio"))
 111       file =    TFile::Open(fHeadersFile,"update") ;
 112     else
 113       file = new TFile(fHeadersFile.Data(),"update") ;
 114     gAlice = (AliRun *) file->Get("gAlice") ;
 115   }
 116
 117   // add Task to //root/Tasks folder
 118   TTask * roottasks = (TTask*)gROOT->GetRootFolder()->FindObject("Tasks") ;
 119   roottasks->Add(this) ;
 120 }
 121
 122 //____________________________________________________________________________
 123   AliTOFT0::~AliTOFT0()
 124 {
 125   // dtor
 126 }
 127
 128 //____________________________________________________________________________
 129 void AliTOFT0::Exec(Option_t *option)
 130 {
 131   //
 132   // calculate T0 distribution for all events using chisquare
 133   //
 134   Int_t ngood=0;
 135   Int_t nmisidentified=0;
 136   Int_t nmisidentified0=0;
 137   Int_t nmisidentified1=0;
 138   Int_t nmisidentified2=0;
 139   Int_t nmisidentified3=0;
 140   Int_t nmisidentified4=0;
 141   Int_t nmisidentified5=0;
 142   Int_t nmisidentified6=0;
 143   Int_t nmisidentified7=0;
 144   Int_t nmisidentified8=0;
 145   Int_t nmisidentified9=0;
 146   Int_t ipartold = -1;
 147   Int_t ipart;
 148   Int_t selected=0;
 149   Int_t istop=0;
 150   Float_t timeresolutioninns=fTimeResolution*(1.e+9); // convert in [ns]
 151   const Int_t kUPDATE = 5; // for visual option
 152   Int_t itimes=0;
 153   TCanvas* c1=0;
 154   TCanvas* c2=0;
 155   TCanvas* c3=0;
 156
 157   if(strstr(option,"visual")){
 158     // Create a new canvas.
 159     //c1 = new TCanvas("c1","Dynamic Visual Filling of time zero histo",10,10,500,500);
 160     c1 = new TCanvas("c1","Dynamic Visual Filling of time zero histo",10,10,370,370);
 161     c1->SetFillColor(35);
 162     c1->GetFrame()->SetFillColor(21);
 163     c1->GetFrame()->SetBorderSize(6);
 164     c1->GetFrame()->SetBorderMode(-1);
 165
 166     //c2 = new TCanvas("c2","Dynamic Visual Filling of chisquare histo",550,10,500,500);
 167     c2 = new TCanvas("c2","Dynamic Visual Filling of chisquare histo",380,10,370,370);
 168     c2->SetFillColor(35);
 169     c2->GetFrame()->SetFillColor(21);
 170     c2->GetFrame()->SetBorderSize(6);
 171     c2->GetFrame()->SetBorderMode(-1);
 172
 173     //c3 = new TCanvas("c3","Dynamic Visual Filling of confidence level histo",280,550,500,500);
 174     c3 = new TCanvas("c3","Dynamic Visual Filling of confidence level histo",760,10,370,370);
 175     c3->SetFillColor(35);
 176     c3->GetFrame()->SetFillColor(21);
 177     c3->GetFrame()->SetBorderSize(6);
 178     c3->GetFrame()->SetBorderMode(-1);
 179   }
 180
 181   if(strstr(option,"tim") || strstr(option,"all"))
 182     gBenchmark->Start("TOFT0");
 183
 184   TH1F *htzerobest= new TH1F("htzerobest","T0 for best assignment",200,-1.,1.);
 185   TH1F* hchibest  = new TH1F("hchibest","ChiSquare Min Distribution",80,0.,40.);
 186   TH1F* hchibestconflevel  = new TH1F("hchibestconflevel","ChiSquare Min Confidence Level",10,0.,1.);
 187
 188   // setting histo colors
 189   if(strstr(option,"visual")){
 190     htzerobest->SetFillColor(48);
 191     hchibest->SetFillColor(50);
 192     hchibestconflevel->SetFillColor(52);
 193   }
 194
 195   Int_t   assparticle[10]={3,3,3,3,3,3,3,3,3,3};
 196   Int_t   truparticle[10]={3,3,3,3,3,3,3,3,3,3};
 197   Float_t t0best=999.;
 198   Float_t timeofflight[10]={0.,0.,0.,0.,0.,0.,0.,0.,0.,0.};
 199   Float_t momentum[10]={0.,0.,0.,0.,0.,0.,0.,0.,0.,0.};
 200   Float_t timezero[10];
 201   Float_t weightedtimezero[10];
 202   Float_t beta[10]={0.,0.,0.,0.,0.,0.,0.,0.,0.,0.};
 203   Float_t sqMomError[10]={0.,0.,0.,0.,0.,0.,0.,0.,0.,0.};
 204   Float_t sqTrackError[10]={0.,0.,0.,0.,0.,0.,0.,0.,0.,0.};
 205   Float_t massarray[3]={0.13957,0.493677,0.9382723};
 206   Float_t dummychisquare=0.;
 207   Float_t chisquare=999.;
 208   Float_t tracktoflen[10]={0.,0.,0.,0.,0.,0.,0.,0.,0.,0.};
 209
 210   AliTOF *TOF = (AliTOF *) gAlice->GetDetector ("TOF");
 211
 212   if (!TOF) {
 213     Error("AliTOFT0","TOF not found");
 214     return;
 215   }
 216
 217   if(strstr(option,"all")){
 218     cout << "Selecting primary tracks with momentum between " << fLowerMomBound << " GeV/c and " << fUpperMomBound << " GeV/c" << endl;
 219     cout << "Memorandum: 0 means PION | 1 means KAON | 2 means PROTON" << endl;
 220   }
 221
 222   if (fNevents == 0) fNevents = (Int_t) gAlice->TreeE()->GetEntries();
 223
 224   for (Int_t ievent = 0; ievent < fNevents; ievent++) {
 225     gAlice->GetEvent(ievent);
 226     TTree *TH = gAlice->TreeH ();
 227     if (!TH)
 228       return;
 229     TParticle*    particle;
 230     AliTOFhitT0*  tofHit;
 231     TClonesArray* TOFhits = TOF->Hits();
 232
 233     Int_t lasttrack=-1;
 234     Int_t nset=0;
 235
 236     TH->SetBranchStatus("*",0); // switch off all branches
 237     TH->SetBranchStatus("TOF*",1); // switch on only TOF
 238
 239     // Start loop on primary tracks in the hits containers
 240
 241     Int_t ntracks = static_cast<Int_t>(TH->GetEntries());
 242     for (Int_t track = 0; track < ntracks; track++)
 243     {
 244       if(nset>=5) break; // check on the number of set analyzed
 245
 246       gAlice->ResetHits();
 247       TH->GetEvent(track);
 248       particle = gAlice->Particle(track);
 249       Int_t nhits = TOFhits->GetEntriesFast();
 250
 251       for (Int_t hit = 0; hit < nhits; hit++)
 252       {
 253         tofHit = (AliTOFhitT0 *) TOFhits->UncheckedAt(hit);
 254         ipart    = tofHit->GetTrack();
 255         // check to discard the case when the same particle is selected more than one
 256         // time
 257
 258         if (ipart != ipartold){
 259
 260           particle = (TParticle*)gAlice->Particle(ipart);
 261
 262           Float_t idealtime=tofHit->GetTof();
 263           //       Float_t time=idealtime;
 264           Float_t time   = gRandom->Gaus(idealtime, fTimeResolution);
 265           Float_t toflen=tofHit->GetLen();
 266           toflen=toflen/100.; // toflen given in m
 267           Int_t pdg   = particle->GetPdgCode();
 268           Int_t abspdg   =TMath::Abs(pdg);
 269           Float_t idealmom  = particle->P();
 270           Float_t momres=idealmom*0.025; // 2.5% res token into account for all momenta
 271           Float_t mom =gRandom->Gaus(idealmom,momres);
 272
 273           Bool_t isgoodpart=(abspdg==211 || abspdg==2212 || abspdg==321);
 274
 275           time*=1.E+9; // tof given in nanoseconds
 276           if (particle->GetFirstMother() < 0 && isgoodpart && mom<=fUpperMomBound && mom>=fLowerMomBound){
 277             selected+=1;
 278             istop=selected;
 279             if(istop>10) break;
 280             Int_t index=selected-1;
 281             timeofflight[index]=time;
 282             tracktoflen[index]=toflen;
 283             momentum[index]=mom;
 284             //      cout << timeofflight[index] << " " << tracktoflen[index] << " " << momentum[index] << endl;
 285             switch (abspdg) {
 286             case 211:
 287               truparticle[index]=0;
 288               break ;
 289             case 321:
 290               truparticle[index]=1;
 291               break ;
 292             case 2212:
 293               truparticle[index]=2;
 294               break ;
 295             }
 296
 297           }
 298           ipartold = ipart;
 299
 300           if(istop==10){ // start analysis on current set
 301             nset+=1;
 302             lasttrack=track;
 303             istop=0;
 304             selected=0;
 305             //cout << "starting t0 calculation for current set" << endl;
 306             for (Int_t i1=0; i1<3;i1++) {
 307               beta[0]=momentum[0]/sqrt(massarray[i1]*massarray[i1]+momentum[0]*momentum[0]);
 308               for (Int_t i2=0; i2<3;i2++) {
 309                 beta[1]=momentum[1]/sqrt(massarray[i2]*massarray[i2]+momentum[1]*momentum[1]);
 310                 for (Int_t i3=0; i3<3;i3++) {
 311                   beta[2]=momentum[2]/sqrt(massarray[i3]*massarray[i3]+momentum[2]*momentum[2]);
 312                   for (Int_t i4=0; i4<3;i4++) {
 313                     beta[3]=momentum[3]/sqrt(massarray[i4]*massarray[i4]+momentum[3]*momentum[3]);
 314                     for (Int_t i5=0; i5<3;i5++) {
 315                       beta[4]=momentum[4]/sqrt(massarray[i5]*massarray[i5]+momentum[4]*momentum[4]);
 316                       for (Int_t i6=0; i6<3;i6++) {
 317                         beta[5]=momentum[5]/sqrt(massarray[i6]*massarray[i6]+momentum[5]*momentum[5]);
 318                         for (Int_t i7=0; i7<3;i7++) {
 319                           beta[6]=momentum[6]/sqrt(massarray[i7]*massarray[i7]+momentum[6]*momentum[6]);
 320                           for (Int_t i8=0; i8<3;i8++) {
 321                             beta[7]=momentum[7]/sqrt(massarray[i8]*massarray[i8]+momentum[7]*momentum[7]);
 322                             for (Int_t i9=0; i9<3;i9++) {
 323                               beta[8]=momentum[8]/sqrt(massarray[i9]*massarray[i9]+momentum[8]*momentum[8]);
 324                               for (Int_t i10=0; i10<3;i10++) {
 325                                 beta[9]=momentum[9]/sqrt(massarray[i10]*massarray[i10]+momentum[9]*momentum[9]);
 326
 327                                 Float_t meantzero=0.;
 328                                 Float_t sumAllweights=0.;
 329                                 for (Int_t itz=0; itz<10;itz++) {
 330                                   sqMomError[itz]=((1.-beta[itz]*beta[itz])*0.025)*((1.-beta[itz]*beta[itz])*0.025)*(tracktoflen[itz]/(0.299792*beta[itz]))*(tracktoflen[itz]/(0.299792*beta[itz])); // this gives the square of the momentum error in nanoseconds
 331                                   sqTrackError[itz]=(timeresolutioninns*timeresolutioninns+sqMomError[itz]); // total error for the current track
 332                                   sumAllweights+=1./sqTrackError[itz];
 333
 334                                   timezero[itz]=(tracktoflen[itz]/(beta[itz]*0.299792))-timeofflight[itz];
 335                                   weightedtimezero[itz]=((tracktoflen[itz]/(beta[itz]*0.299792))-timeofflight[itz])/sqTrackError[itz];// weighted time zero for current track
 336                                   meantzero+=weightedtimezero[itz];
 337                                 } // end loop for (Int_t itz=0; itz<10;itz++)
 338                                 meantzero=meantzero/sumAllweights; // it is given in [ns]
 339
 340                                 dummychisquare=0.;
 341                                 // calculate the chisquare for the current assignment
 342                                 for (Int_t icsq=0; icsq<10;icsq++) {
 343                                   dummychisquare+=(timezero[icsq]-meantzero)*(timezero[icsq]-meantzero)/sqTrackError[icsq];
 344                                 } // end loop for (Int_t icsq=0; icsq<10;icsq++)
 345
 346                                 if(dummychisquare<=chisquare){
 347                                   assparticle[0]=i1;
 348                                   assparticle[1]=i2;
 349                                   assparticle[2]=i3;
 350                                   assparticle[3]=i4;
 351                                   assparticle[4]=i5;
 352                                   assparticle[5]=i6;
 353                                   assparticle[6]=i7;
 354                                   assparticle[7]=i8;
 355                                   assparticle[8]=i9;
 356                                   assparticle[9]=i10;
 357                                   chisquare=dummychisquare;
 358                                   t0best=meantzero;
 359                                 } // close if(dummychisquare<=chisquare)
 360
 361                               } // end loop on i10
 362                             } // end loop on i9
 363                           } // end loop on i8
 364                         } // end loop on i7
 365                       } // end loop on i6
 366                     } // end loop on i5
 367                   } // end loop on i4
 368                 } // end loop on i3
 369               } // end loop on i2
 370             } // end loop on i1
 371
 372             if(truparticle[0]==assparticle[0] && truparticle[1]==assparticle[1] && truparticle[2]==assparticle[2]  && truparticle[3]==assparticle[3] && truparticle[4]==assparticle[4]&& truparticle[5]==assparticle[5] && truparticle[6]==assparticle[6] && truparticle[7]==assparticle[7]  && truparticle[8]==assparticle[8] && truparticle[9]==assparticle[9]) ngood+=1;
 373             if(truparticle[0]!=assparticle[0]) nmisidentified0+=1;
 374             if(truparticle[1]!=assparticle[1]) nmisidentified1+=1;
 375             if(truparticle[2]!=assparticle[2]) nmisidentified2+=1;
 376             if(truparticle[3]!=assparticle[3]) nmisidentified3+=1;
 377             if(truparticle[4]!=assparticle[4]) nmisidentified4+=1;
 378             if(truparticle[5]!=assparticle[5]) nmisidentified5+=1;
 379             if(truparticle[6]!=assparticle[6]) nmisidentified6+=1;
 380             if(truparticle[7]!=assparticle[7]) nmisidentified7+=1;
 381             if(truparticle[8]!=assparticle[8]) nmisidentified8+=1;
 382             if(truparticle[9]!=assparticle[9]) nmisidentified9+=1;
 383             // filling histos
 384             htzerobest->Fill(t0best);
 385             hchibest->Fill(chisquare);
 386             Double_t dblechisquare=(Double_t)chisquare;
 387             Float_t confLevel=(Float_t)TMath::Prob(dblechisquare,9); // ndf 10-1=9
 388             hchibestconflevel->Fill(confLevel);
 389             itimes++;
 390             if(strstr(option,"all")){
 391               cout << "True Assignment " << truparticle[0] << truparticle[1] << truparticle[2] << truparticle[3] << truparticle[4] << truparticle[5] << truparticle[6] << truparticle[7] << truparticle[8] << truparticle[9] <<endl;
 392               cout << "Best Assignment " << assparticle[0] << assparticle[1] << assparticle[2] << assparticle[3] << assparticle[4] << assparticle[5] << assparticle[6] << assparticle[7] << assparticle[8] << assparticle[9] << endl;
 393               cout << "Minimum ChiSquare for current set    " << chisquare << endl;
 394               cout << "Confidence Level (Minimum ChiSquare) " << confLevel << endl;
 395             }
 396             if (strstr(option,"visual") && itimes && (itimes%kUPDATE) == 0) {
 397               if (itimes == kUPDATE){
 398                 c1->cd();
 399                 htzerobest->Draw();
 400                 c2->cd();
 401                 hchibest->Draw();
 402                 c3->cd();
 403                 hchibestconflevel->Draw();
 404               }
 405               c1->Modified();
 406               c1->Update();
 407               c2->Modified();
 408               c2->Update();
 409               c3->Modified();
 410               c3->Update();
 411               if (gSystem->ProcessEvents())
 412                 break;
 413             }
 414             chisquare=999.;
 415             t0best=999.;
 416
 417           } // end for the current set. close if(istop==5)
 418         } // end condition on ipartold
 419       } // end loop on hits for the current track
 420       if(istop>=10) break;
 421     } // end loop on ntracks
 422   } //event loop
 423
 424   if(strstr(option,"all")){
 425     nmisidentified=(nmisidentified0+nmisidentified1+nmisidentified2+nmisidentified3+nmisidentified4+nmisidentified5+nmisidentified6+nmisidentified7+nmisidentified8+nmisidentified9);
 426     cout << "total number of tracks token into account  " << 10*5*fNevents << endl;
 427     Float_t badPercentage=100.*(Float_t)nmisidentified/(10*5*fNevents);
 428     cout << "total misidentified                        " << nmisidentified << "("<< badPercentage << "%)" <<endl;
 429     cout << "Total Number of set token into account     " << 5*fNevents << endl;
 430     Float_t goodSetPercentage=100.*(Float_t)ngood/(5*fNevents);
 431     cout << "Number of set with no misidentified tracks " << ngood << "("<< goodSetPercentage << "%)" <<endl;
 432   }
 433
 434   // free used memory for canvas
 435   delete c1; c1=0;
 436   delete c2; c2=0;
 437   delete c3; c3=0;
 438
 439   // generating output filename only if not previously specified using SetTZeroFile
 440   char outFileName[70];
 441   strcpy(outFileName,"ht010tr120ps"); // global time resolution has to be converted from Int_t to char
 442                                       // in order to have in the output filename this parameter
 443   strcat(outFileName,fHeadersFile);
 444
 445   if(fT0File.IsNull()) fT0File=outFileName;
 446
 447   TFile* houtfile = new TFile(fT0File,"recreate");
 448   houtfile->cd();
 449   htzerobest->Write(0,TObject::kOverwrite);
 450   hchibest->Write(0,TObject::kOverwrite);
 451   hchibestconflevel->Write(0,TObject::kOverwrite);
 452   houtfile->Close();
 453
 454
 455   if(strstr(option,"tim") || strstr(option,"all")){
 456     gBenchmark->Stop("TOFT0");
 457     cout << "AliTOFT0:" << endl ;
 458     cout << "   took " << gBenchmark->GetCpuTime("TOFT0") << " seconds in order to calculate T0 "
 459          <<  gBenchmark->GetCpuTime("TOFT0")/fNevents << " seconds per event " << endl ;
 460     cout << endl ;
 461   }
 462 }
 463
 464 //__________________________________________________________________
 465 void AliTOFT0::SetTZeroFile(char * file ){
 466   cout << "Destination file : " << file << endl ;
 467   fT0File=file;
 468 }
 469 //__________________________________________________________________
 470 void AliTOFT0::Print(Option_t* option)const
 471 {
 472   cout << "------------------- "<< GetName() << " -------------" << endl ;
 473   if(!fT0File.IsNull())
 474     cout << "  Writing T0 Distribution to file  " << (char*) fT0File.Data() << endl ;
 475 }
 476
 477 //__________________________________________________________________
 478 Bool_t AliTOFT0::operator==( AliTOFT0 const &tzero )const
 479 {
 480   // Equal operator.
 481   //
 482
 483   if( (fTimeResolution==tzero.fTimeResolution)&&(fLowerMomBound==tzero.fLowerMomBound)&&(fUpperMomBound==tzero.fUpperMomBound))
 484     return kTRUE ;
 485   else
 486     return kFALSE ;
 487 }
 488