TPC/AliTPCComparison.C

   1 /****************************************************************************
   2  *           Very important, delicate and rather obscure macro.             *
   3  *                                                                          *
   4  *               Creates list of "trackable" tracks,                        *
   5  *             calculates efficiency, resolutions etc.                      *
   6  *     There is a possibility to run this macro over several events.         *
   7  *                                                                          *
   8  *           Origin: I.Belikov, CERN, Jouri.Belikov@cern.ch                 *
   9  * with several nice improvements by: M.Ivanov, GSI, m.ivanov@gsi.de        *
  10  ****************************************************************************/
  11
  12 #if !defined(__CINT__) || defined(__MAKECINT__)
  13   #include <TMath.h>
  14   #include <TError.h>
  15   #include <Riostream.h>
  16   #include <TH1F.h>
  17   #include <TH2F.h>
  18   #include <TTree.h>
  19   #include <TParticle.h>
  20   #include <TCanvas.h>
  21   #include <TLine.h>
  22   #include <TText.h>
  23   #include <TBenchmark.h>
  24   #include <TStyle.h>
  25   #include <TFile.h>
  26   #include <TROOT.h>
  27
  28   #include "AliStack.h"
  29   #include "AliHeader.h"
  30   #include "AliTrackReference.h"
  31   #include "AliRunLoader.h"
  32   #include "AliRun.h"
  33   #include "AliESDEvent.h"
  34   #include "AliESDtrack.h"
  35
  36   #include "AliSimDigits.h"
  37   #include "AliTPC.h"
  38   #include "AliTPCParamSR.h"
  39   #include "AliTPCClustersArray.h"
  40   #include "AliTPCClustersRow.h"
  41   #include "AliTPCcluster.h"
  42   #include "AliTPCLoader.h"
  43
  44   #include "AliCDBManager.h"
  45   #include "AliTPCcalibDB.h"
  46 #endif
  47
  48 Int_t GoodTracksTPC(const Char_t *dir=".");
  49
  50 extern TBenchmark *gBenchmark;
  51 extern TROOT *gROOT;
  52
  53 static Int_t allgood=0;
  54 static Int_t allselected=0;
  55 static Int_t allfound=0;
  56
  57 Int_t AliTPCComparison
  58 (Float_t ptcutl=0.2, Float_t ptcuth=10., const Char_t *dir=".") {
  59    gBenchmark->Start("AliTPCComparison");
  60
  61    ::Info("AliTPCComparison.C","Doing comparison...");
  62
  63
  64
  65    TH1F *hp=(TH1F*)gROOT->FindObject("hp");
  66    if (!hp) hp=new TH1F("hp","PHI resolution",50,-20.,20.);
  67    hp->SetFillColor(4);
  68
  69    TH1F *hl=(TH1F*)gROOT->FindObject("hl");
  70    if (!hl) hl=new TH1F("hl","LAMBDA resolution",50,-20,20);
  71    hl->SetFillColor(4);
  72
  73    TH1F *hpt=(TH1F*)gROOT->FindObject("hpt");
  74    if (!hpt) hpt=new TH1F("hpt","Relative Pt resolution",30,-10.,10.);
  75    hpt->SetFillColor(2);
  76
  77    TH1F *hmpt=(TH1F*)gROOT->FindObject("hmpt");
  78    if (!hmpt)
  79       hmpt=new TH1F("hmpt","Relative Pt resolution (pt>4GeV/c)",30,-60,60);
  80    hmpt->SetFillColor(6);
  81
  82
  83
  84    TH1F *hgood=(TH1F*)gROOT->FindObject("hgood");
  85    if (!hgood) hgood=new TH1F("hgood","Good tracks",30,0.2,6.1);
  86
  87    TH1F *hfound=(TH1F*)gROOT->FindObject("hfound");
  88    if (!hfound) hfound=new TH1F("hfound","Found tracks",30,0.2,6.1);
  89
  90    TH1F *hfake=(TH1F*)gROOT->FindObject("hfake");
  91    if (!hfake) hfake=new TH1F("hfake","Fake tracks",30,0.2,6.1);
  92
  93    TH1F *hg=(TH1F*)gROOT->FindObject("hg");
  94    if (!hg) hg=new TH1F("hg","Efficiency for good tracks",30,0.2,6.1);
  95    hg->SetLineColor(4); hg->SetLineWidth(2);
  96
  97    TH1F *hf=(TH1F*)gROOT->FindObject("hf");
  98    if (!hf) hf=new TH1F("hf","Efficiency for fake tracks",30,0.2,6.1);
  99    hf->SetFillColor(1); hf->SetFillStyle(3013); hf->SetLineWidth(2);
 100
 101    TH1F *he=(TH1F*)gROOT->FindObject("he");
 102    if (!he)
 103       he =new TH1F("he","dE/dX for pions with 0.4<p<0.5 GeV/c",50,0.,100.);
 104
 105    TH2F *hep=(TH2F*)gROOT->FindObject("hep");
 106    if (!hep) hep=new TH2F("hep","dE/dX vs momentum",50,0.,2.,50,0.,400.);
 107    hep->SetMarkerStyle(8);
 108    hep->SetMarkerSize(0.4);
 109
 110
 111    Char_t fname[100];
 112    sprintf(fname,"%s/GoodTracksTPC.root",dir);
 113
 114    TFile *refFile=TFile::Open(fname,"old");
 115    if (!refFile || !refFile->IsOpen()) {
 116      ::Info("AliTPCComparison.C","Marking good tracks (will take a while)...");
 117      if (GoodTracksTPC(dir)) {
 118         ::Error("AliTPCComparison.C","Can't generate the reference file !");
 119         return 1;
 120      }
 121    }
 122    refFile=TFile::Open(fname,"old");
 123    if (!refFile || !refFile->IsOpen()) {
 124      ::Error("AliTPCComparison.C","Can't open the reference file !");
 125      return 2;
 126    }
 127
 128    TTree *tpcTree=(TTree*)refFile->Get("tpcTree");
 129    if (!tpcTree) {
 130      ::Error("AliTPCComparison.C","Can't get the reference tree !");
 131      return 3;
 132    }
 133    TBranch *branch=tpcTree->GetBranch("TPC");
 134    if (!branch) {
 135      ::Error("AliTPCComparison.C","Can't get the TPC branch !");
 136      return 4;
 137    }
 138    TClonesArray dummy("AliTrackReference",1000), *refs=&dummy;
 139    branch->SetAddress(&refs);
 140
 141
 142    sprintf(fname,"%s/AliESDs.root",dir);
 143    TFile *ef=TFile::Open(fname);
 144    if ((!ef)||(!ef->IsOpen())) {
 145       sprintf(fname,"%s/AliESDtpc.root",dir);
 146       ef=TFile::Open(fname);
 147       if ((!ef)||(!ef->IsOpen())) {
 148          ::Error("AliTPCComparison.C","Can't open AliESDtpc.root !");
 149          return 5;
 150       }
 151    }
 152    AliESDEvent* event = new AliESDEvent();
 153    TTree* esdTree = (TTree*) ef->Get("esdTree");
 154    if (!esdTree) {
 155       ::Error("AliTPCComparison.C", "no ESD tree found");
 156       return 6;
 157    }
 158    event->ReadFromTree(esdTree);
 159
 160
 161    //******* Loop over events *********
 162    Int_t e=0;
 163    while (esdTree->GetEvent(e)) {
 164       cout<<endl<<endl<<"********* Processing event number: "<<e<<"*******\n";
 165
 166       Int_t nentr=event->GetNumberOfTracks();
 167       allfound+=nentr;
 168
 169       if (tpcTree->GetEvent(e++)==0) {
 170          cerr<<"No reconstructable tracks !\n";
 171          continue;
 172       }
 173
 174       Int_t ngood=refs->GetEntriesFast();
 175       allgood+=ngood;
 176
 177       const Int_t MAX=15000;
 178     //MI change
 179       Int_t track_notfound[MAX], itrack_notfound=0;
 180       Int_t track_fake[MAX], itrack_fake=0;
 181       Int_t track_multifound[MAX],track_multifound_n[MAX],itrack_multifound=0;
 182
 183       Int_t i;
 184       for (Int_t k=0; k<ngood; k++) {
 185         AliTrackReference *ref=(AliTrackReference*)refs->UncheckedAt(k);
 186         Int_t lab=ref->Label(), tlab=-1;
 187         Float_t ptg=TMath::Sqrt(ref->Px()*ref->Px() + ref->Py()*ref->Py());
 188
 189         if (ptg<1e-33) continue; // for those not crossing 0 pad row
 190
 191         if (ptg<ptcutl) continue;
 192         if (ptg>ptcuth) continue;
 193
 194         allselected++;
 195
 196         hgood->Fill(ptg);
 197
 198         AliESDtrack *track=0;
 199         for (i=0; i<nentr; i++) {
 200           track=event->GetTrack(i);
 201           tlab=track->GetTPCLabel();
 202           if (lab==TMath::Abs(tlab)) break;
 203         }
 204         if (i==nentr) {
 205            track_notfound[itrack_notfound++]=lab;
 206            continue;
 207         }
 208
 209         //MI change  - addition
 210         Int_t micount=0;
 211         Int_t mi;
 212         AliESDtrack * mitrack;
 213         for (mi=0; mi<nentr; mi++) {
 214           mitrack=event->GetTrack(mi);
 215           if (lab==TMath::Abs(mitrack->GetTPCLabel())) micount++;
 216         }
 217         if (micount>1) {
 218           track_multifound[itrack_multifound]=lab;
 219           track_multifound_n[itrack_multifound]=micount;
 220           itrack_multifound++;
 221         }
 222         if ((track->GetStatus()&AliESDtrack::kTPCrefit)==0) continue;
 223         if (lab==tlab) hfound->Fill(ptg);
 224         else {
 225           track_fake[itrack_fake++]=lab;
 226           hfake->Fill(ptg);
 227         }
 228
 229         Double_t pxpypz[3]; track->GetInnerPxPyPz(pxpypz);
 230         Float_t phi=TMath::ATan2(pxpypz[1],pxpypz[0]);
 231         if (phi<-TMath::Pi()) phi+=2*TMath::Pi();
 232         if (phi>=TMath::Pi()) phi-=2*TMath::Pi();
 233         Double_t pt=TMath::Sqrt(pxpypz[0]*pxpypz[0]+pxpypz[1]*pxpypz[1]);
 234         Float_t lam=TMath::ATan2(pxpypz[2],pt);
 235         Float_t pt_1=1/pt;
 236
 237         Int_t pdg=(Int_t)ref->GetLength();  //this is particle's PDG !
 238
 239         if (TMath::Abs(pdg)==11 && ptg>4.) {//high momentum electrons
 240            hmpt->Fill((pt_1 - 1/ptg)/(1/ptg)*100.);
 241         } else {
 242            Float_t phig=TMath::ATan2(ref->Py(),ref->Px());
 243            hp->Fill((phi - phig)*1000.);
 244
 245            Float_t lamg=TMath::ATan2(ref->Pz(),ptg);
 246            hl->Fill((lam - lamg)*1000.);
 247
 248            hpt->Fill((pt_1 - 1/ptg)/(1/ptg)*100.);
 249         }
 250
 251         Float_t mom=pt/TMath::Cos(lam);
 252         Float_t dedx=track->GetTPCsignal();
 253         hep->Fill(mom,dedx,1.);
 254         if (TMath::Abs(pdg)==211) //pions
 255            if (mom>0.4 && mom<0.5) {
 256               he->Fill(dedx,1.);
 257            }
 258       }
 259
 260       cout<<"\nList of Not found tracks :\n";
 261       for ( i = 0; i< itrack_notfound; i++){
 262         cout<<track_notfound[i]<<"\t";
 263         if ((i%5)==4) cout<<"\n";
 264       }
 265       cout<<"\nList of fake  tracks :\n";
 266       for ( i = 0; i< itrack_fake; i++){
 267         cout<<track_fake[i]<<"\t";
 268         if ((i%5)==4) cout<<"\n";
 269       }
 270       cout<<"\nList of multiple found tracks :\n";
 271       for ( i=0; i<itrack_multifound; i++) {
 272           cout<<"id.   "<<track_multifound[i]
 273               <<"     found - "<<track_multifound_n[i]<<"times\n";
 274       }
 275
 276       cout<<"Number of found tracks ="<<nentr<<endl;
 277       cout<<"Number of \"good\" tracks ="<<ngood<<endl;
 278
 279       refs->Clear();
 280   }// ***** End of the loop over events
 281
 282    delete event;
 283    delete esdTree;
 284    ef->Close();
 285
 286    delete tpcTree;
 287    refFile->Close();
 288
 289    Stat_t ng=hgood->GetEntries(), nf=hfound->GetEntries();
 290    if (ng!=0) cout<<"\n\nIntegral efficiency is about "<<nf/ng*100.<<" %\n";
 291    cout<<"Total number selected of \"good\" tracks ="<<allselected<<endl<<endl;
 292    cout<<"Total number of found tracks ="<<allfound<<endl;
 293    cout<<"Total number of \"good\" tracks ="<<allgood<<endl;
 294    cout<<endl;
 295
 296    gStyle->SetOptStat(111110);
 297    gStyle->SetOptFit(1);
 298
 299    TCanvas *c1=new TCanvas("c1","",0,0,700,850);
 300
 301    Int_t minc=33;
 302
 303    TPad *p1=new TPad("p1","",0,0.3,.5,.6); p1->Draw();
 304    p1->cd(); p1->SetFillColor(42); p1->SetFrameFillColor(10);
 305    hp->SetFillColor(4);  hp->SetXTitle("(mrad)");
 306    if (hp->GetEntries()<minc) hp->Draw(); else hp->Fit("gaus"); c1->cd();
 307
 308    TPad *p2=new TPad("p2","",0.5,.3,1,.6); p2->Draw();
 309    p2->cd(); p2->SetFillColor(42); p2->SetFrameFillColor(10);
 310    hl->SetXTitle("(mrad)");
 311    if (hl->GetEntries()<minc) hl->Draw(); else hl->Fit("gaus"); c1->cd();
 312
 313    TPad *p3=new TPad("p3","",0,0,0.5,0.3); p3->Draw();
 314    p3->cd(); p3->SetFillColor(42); p3->SetFrameFillColor(10);
 315    hpt->SetXTitle("(%)");
 316    if (hpt->GetEntries()<minc) hpt->Draw(); else hpt->Fit("gaus"); c1->cd();
 317
 318    TPad *p4=new TPad("p4","",0.5,0,1,0.3); p4->Draw();
 319    p4->cd(); p4->SetFillColor(42); p4->SetFrameFillColor(10);
 320    hmpt->SetXTitle("(%)");
 321    if (hmpt->GetEntries()<minc) hmpt->Draw(); else hmpt->Fit("gaus"); c1->cd();
 322
 323    TPad *p5=new TPad("p5","",0,0.6,1,1); p5->Draw(); p5->cd();
 324    p5->SetFillColor(41); p5->SetFrameFillColor(10);
 325    hfound->Sumw2(); hgood->Sumw2(); hfake->Sumw2();
 326    hg->Divide(hfound,hgood,1,1.,"b");
 327    hf->Divide(hfake,hgood,1,1.,"b");
 328    hg->SetMaximum(1.4);
 329    hg->SetYTitle("Tracking efficiency");
 330    hg->SetXTitle("Pt (GeV/c)");
 331    hg->Draw();
 332
 333    TLine *line1 = new TLine(0.1,1.0,6.1,1.0); line1->SetLineStyle(4);
 334    line1->Draw("same");
 335    TLine *line2 = new TLine(0.1,0.9,6.1,0.9); line2->SetLineStyle(4);
 336    line2->Draw("same");
 337
 338    hf->SetFillColor(1);
 339    hf->SetFillStyle(3013);
 340    hf->SetLineColor(2);
 341    hf->SetLineWidth(2);
 342    hf->Draw("histsame");
 343    TText *text = new TText(0.461176,0.248448,"Fake tracks");
 344    text->SetTextSize(0.05);
 345    text->Draw();
 346    text = new TText(0.453919,1.11408,"Good tracks");
 347    text->SetTextSize(0.05);
 348    text->Draw();
 349
 350
 351
 352    TCanvas *c2=new TCanvas("c2","",320,32,530,590);
 353
 354    TPad *p6=new TPad("p6","",0.,0.,1.,.5); p6->Draw();
 355    p6->cd(); p6->SetFillColor(42); p6->SetFrameFillColor(10);
 356    he->SetFillColor(2); he->SetFillStyle(3005);
 357    he->SetXTitle("Arbitrary Units");
 358    if (he->GetEntries()<minc) he->Draw(); else he->Fit("gaus"); c2->cd();
 359
 360    TPad *p7=new TPad("p7","",0.,0.5,1.,1.); p7->Draw();
 361    p7->cd(); p7->SetFillColor(42); p7->SetFrameFillColor(10);
 362    hep->SetXTitle("p (Gev/c)"); hep->SetYTitle("dE/dX (Arb. Units)");
 363    hep->Draw(); c1->cd();
 364
 365    TFile fc("AliTPCComparison.root","RECREATE");
 366    c1->Write();
 367    c2->Write();
 368    fc.Close();
 369
 370    gBenchmark->Stop("AliTPCComparison");
 371    gBenchmark->Show("AliTPCComparison");
 372
 373    return 0;
 374 }
 375
 376
 377 Int_t GoodTracksTPC(const Char_t *dir) {
 378    Char_t fname[100];
 379    sprintf(fname,"%s/galice.root",dir);
 380
 381    AliRunLoader *rl = AliRunLoader::Open(fname,"COMPARISON");
 382    if (!rl) {
 383       ::Error("GoodTracksTPC","Can't start session !");
 384       return 1;
 385    }
 386
 387    rl->LoadgAlice();
 388    rl->LoadHeader();
 389    rl->LoadKinematics();
 390    rl->LoadTrackRefs();
 391
 392    AliTPCLoader *tpcl = (AliTPCLoader *)rl->GetLoader("TPCLoader");
 393    if (tpcl == 0x0) {
 394       ::Error("GoodTracksTPC","Can not find TPCLoader !");
 395       delete rl;
 396       return 2;
 397    }
 398
 399    AliTPC *TPC=(AliTPC*)rl->GetAliRun()->GetDetector("TPC");
 400    Int_t ver = TPC->IsVersion();
 401    cout<<"TPC version "<<ver<<" has been found !\n";
 402    if (ver==1) tpcl->LoadRecPoints();
 403    else if (ver==2) tpcl->LoadDigits();
 404    else {
 405       ::Error("GoodTracksTPC","Wrong TPC version !");
 406       delete rl;
 407       return 3;
 408    }
 409
 410
 411    AliCDBManager *man=AliCDBManager::Instance();
 412    man->SetDefaultStorage("local://$ALICE_ROOT/OCDB");
 413    man->SetRun(0);
 414    AliTPCParamSR *digp=
 415    (AliTPCParamSR*)(AliTPCcalibDB::Instance()->GetParameters());
 416    if (!digp) {
 417      ::Error("AliTPCComparison.C","TPC parameters have not been found !");
 418      delete rl;
 419      return 4;
 420    }
 421
 422    Int_t nrow_up=digp->GetNRowUp();
 423    Int_t nrows=digp->GetNRowLow()+nrow_up;
 424    Int_t zero=digp->GetZeroSup();
 425    Int_t gap=Int_t(0.125*nrows), shift=Int_t(0.5*gap);
 426    Int_t good_number=Int_t(0.4*nrows);
 427
 428    Int_t nev=rl->GetNumberOfEvents();
 429    ::Info("GoodTracksTPC","Number of events : %d\n",nev);
 430
 431
 432    sprintf(fname,"%s/GoodTracksTPC.root",dir);
 433    TFile *file=TFile::Open(fname,"recreate");
 434
 435    TClonesArray dummy("AliTrackReference",1000), *refs=&dummy;
 436    TTree tpcTree("tpcTree","Tree with info about the reconstructable TPC tracks");
 437    tpcTree.Branch("TPC",&refs);
 438
 439    //********  Loop over generated events
 440    for (Int_t e=0; e<nev; e++) {
 441      Int_t nt=0;
 442      refs->Clear();
 443
 444      Int_t i;
 445
 446      rl->GetEvent(e);  file->cd();
 447
 448      Int_t np = rl->GetHeader()->GetNtrack();
 449      cout<<"Event "<<e<<" Number of particles: "<<np<<endl;
 450
 451      //******** Fill the "good" masks
 452      Int_t *good=new Int_t[np]; for (i=0; i<np; i++) good[i]=0;
 453      switch (ver) {
 454      case 1:
 455         {
 456         AliTPCClustersArray *pca=new AliTPCClustersArray, &ca=*pca;
 457         ca.Setup(digp);
 458         ca.SetClusterType("AliTPCcluster");
 459         ca.ConnectTree(tpcl->TreeR());
 460         Int_t nrows=Int_t(ca.GetTree()->GetEntries());
 461         for (Int_t n=0; n<nrows; n++) {
 462           AliSegmentID *s=ca.LoadEntry(n);
 463           Int_t sec,row;
 464           digp->AdjustSectorRow(s->GetID(),sec,row);
 465           AliTPCClustersRow &clrow = *ca.GetRow(sec,row);
 466           Int_t ncl=clrow.GetArray()->GetEntriesFast();
 467           while (ncl--) {
 468               AliTPCcluster *c=(AliTPCcluster*)clrow[ncl];
 469               Int_t lab=c->GetLabel(0);
 470               if (lab<0) continue; //noise cluster
 471               lab=TMath::Abs(lab);
 472
 473               if (sec>=digp->GetNInnerSector())
 474                  if (row==nrow_up-1) good[lab]|=0x4000;
 475               if (sec>=digp->GetNInnerSector())
 476                  if (row==nrow_up-1-gap) good[lab]|=0x1000;
 477
 478               if (sec>=digp->GetNInnerSector())
 479                  if (row==nrow_up-1-shift) good[lab]|=0x2000;
 480               if (sec>=digp->GetNInnerSector())
 481                  if (row==nrow_up-1-gap-shift) good[lab]|=0x800;
 482
 483               good[lab]++;
 484           }
 485           ca.ClearRow(sec,row);
 486         }
 487         delete pca;
 488         }
 489         break;
 490      case 2:
 491         {
 492         TTree *TD=tpcl->TreeD();
 493
 494         AliSimDigits da, *digits=&da;
 495         TD->GetBranch("Segment")->SetAddress(&digits);
 496
 497         Int_t *count = new Int_t[np];
 498         Int_t i;
 499         for (i=0; i<np; i++) count[i]=0;
 500
 501         Int_t sectors_by_rows=(Int_t)TD->GetEntries();
 502         for (i=0; i<sectors_by_rows; i++) {
 503           if (!TD->GetEvent(i)) continue;
 504           Int_t sec,row;
 505           digp->AdjustSectorRow(digits->GetID(),sec,row);
 506           //cerr<<sec<<' '<<row<<'\r';
 507           digits->First();
 508           do { //Many thanks to J.Chudoba who noticed this
 509               Int_t it=digits->CurrentRow(), ip=digits->CurrentColumn();
 510               Short_t dig = digits->GetDigit(it,ip);
 511               Int_t idx0=digits->GetTrackID(it,ip,0);
 512               Int_t idx1=digits->GetTrackID(it,ip,1);
 513               Int_t idx2=digits->GetTrackID(it,ip,2);
 514               if (idx0>=0 && dig>=zero && idx0<np) count[idx0]+=1;
 515               if (idx1>=0 && dig>=zero && idx1<np) count[idx1]+=1;
 516               if (idx2>=0 && dig>=zero && idx2<np) count[idx2]+=1;
 517           } while (digits->Next());
 518           for (Int_t j=0; j<np; j++) {
 519               if (count[j]>1) {
 520                  if (sec>=digp->GetNInnerSector())
 521                    if (row==nrow_up-1    ) good[j]|=0x4000;
 522                  if (sec>=digp->GetNInnerSector())
 523                    if (row==nrow_up-1-gap) good[j]|=0x1000;
 524
 525                  if (sec>=digp->GetNInnerSector())
 526                    if (row==nrow_up-1-shift) good[j]|=0x2000;
 527                  if (sec>=digp->GetNInnerSector())
 528                    if (row==nrow_up-1-gap-shift) good[j]|=0x800;
 529                  good[j]++;
 530               }
 531               count[j]=0;
 532           }
 533         }
 534         delete[] count;
 535         }
 536         break;
 537      }
 538
 539
 540      //****** select tracks which are "good" enough
 541      AliStack* stack = rl->Stack();
 542      for (i=0; i<np; i++) {
 543         if ((good[i]&0x5000) != 0x5000)
 544         if ((good[i]&0x2800) != 0x2800) continue;
 545         if ((good[i]&0x7FF ) < good_number) continue;
 546
 547         TParticle *p = (TParticle*)stack->Particle(i);
 548         if (p == 0x0) {
 549          cerr<<"Can not get particle "<<i<<endl;
 550          continue;
 551         }
 552         if (p->Pt()<0.100) continue;
 553         if (TMath::Abs(p->Pz()/p->Pt())>0.999) continue;
 554
 555         Double_t vx=p->Vx(),vy=p->Vy(),vz=p->Vz();
 556         if (TMath::Sqrt(vx*vx+vy*vy)>3.5) continue;
 557         if (TMath::Abs(vz) > 50.) continue;
 558
 559         AliTrackReference *ref=new((*refs)[nt]) AliTrackReference();
 560
 561         ref->SetLabel(i);
 562         Int_t pdg=p->GetPdgCode();
 563         ref->SetLength(pdg);  //This will the particle's PDG !
 564         ref->SetMomentum(0.,0.,0.);
 565         ref->SetPosition(0.,0.,0.);
 566
 567         nt++;
 568      }
 569
 570      //**** check if there is also information at the entrance of the TPC
 571      TTree *TR=rl->TreeTR();
 572      TBranch *branch=TR->GetBranch("TrackReferences");
 573      if (branch==0) {
 574         ::Error("GoodTracksTPC","No track references !");
 575         delete rl;
 576         return 5;
 577      }
 578      TClonesArray tpcdummy("AliTrackReference",1000), *tpcRefs=&tpcdummy;
 579      branch->SetAddress(&tpcRefs);
 580      Int_t nr=(Int_t)TR->GetEntries();
 581      for (Int_t r=0; r<nr; r++) {
 582          //cerr<<r<<' '<<nr<<'\r';
 583          TR->GetEvent(r);
 584
 585          Int_t nref = tpcRefs->GetEntriesFast();
 586          if (!nref) continue;
 587          AliTrackReference *tpcRef= 0x0;
 588          for (Int_t iref=0; iref<nref; ++iref) {
 589            tpcRef = (AliTrackReference*)tpcRefs->UncheckedAt(iref);
 590            if (tpcRef->DetectorId() == AliTrackReference::kTPC) break;
 591            tpcRef = 0x0;
 592          }
 593
 594          if (!tpcRef) continue;
 595
 596          Int_t j;
 597          AliTrackReference *ref=0;
 598          for (j=0; j<nt; j++) {
 599            ref=(AliTrackReference *)refs->UncheckedAt(j);
 600            if (ref->Label()==tpcRef->Label()) break;
 601            ref=0;
 602          }
 603          if (ref==0) continue;
 604
 605          ref->SetMomentum(tpcRef->Px(),tpcRef->Py(),tpcRef->Pz());
 606          ref->SetPosition(tpcRef->LocalX(),tpcRef->LocalY(),tpcRef->Z());
 607
 608          tpcRefs->Clear();
 609      }
 610
 611      tpcTree.Fill();
 612
 613      delete[] good;
 614    } //****** end of the loop over generated events
 615
 616
 617    tpcTree.Write();
 618    file->Close();
 619
 620    delete rl;
 621    return 0;
 622 }