ITS/UPGRADE/macros/AliTPCUComparison.C

   1 /****************************************************************************
   2  *           Legacy comparison macro, adapted to the upgraded ITS.          *
   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, IPHC, Iouri.Belikov@iphc.cnrs.fr            *
   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   #include <TGeoGlobalMagField.h>
  28
  29   #include "AliStack.h"
  30   #include "AliHeader.h"
  31   #include "AliTrackReference.h"
  32   #include "AliRunLoader.h"
  33   #include "AliRun.h"
  34   #include "AliMagF.h"
  35   #include "AliESDEvent.h"
  36   #include "AliESDtrack.h"
  37
  38   #include "Base/AliSimDigits.h"
  39   #include "Base/AliTPCParamSR.h"
  40   #include "Base/AliTPCLoader.h"
  41   #include "Base/AliTPCcalibDB.h"
  42   #include "Sim/AliTPC.h"
  43   #include "Rec/AliTPCClustersRow.h"
  44
  45   #include "AliCDBManager.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 AliTPCUComparison
  58 (Float_t ptcutl=0., Float_t ptcuth=2., const Char_t *dir=".") {
  59    gBenchmark->Start("AliTPCUComparison");
  60
  61    ::Info("AliTPCUComparison.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    Int_t nb=100;
  84    TH1F *hgood=(TH1F*)gROOT->FindObject("hgood");
  85    if (!hgood) hgood=new TH1F("hgood","Good tracks",nb,ptcutl,ptcuth);
  86
  87    TH1F *hfound=(TH1F*)gROOT->FindObject("hfound");
  88    if (!hfound) hfound=new TH1F("hfound","Found tracks",nb,ptcutl,ptcuth);
  89
  90    TH1F *hfake=(TH1F*)gROOT->FindObject("hfake");
  91    if (!hfake) hfake=new TH1F("hfake","Fake tracks",nb,ptcutl,ptcuth);
  92
  93    TH1F *hg=(TH1F*)gROOT->FindObject("hg");
  94    if (!hg) hg=new TH1F("hg","Efficiency for good tracks",nb,ptcutl,ptcuth);
  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",nb,ptcutl,ptcuth);
  99    hf->SetFillColor(1); hf->SetFillStyle(3013); hf->SetLineWidth(2);
 100
 101
 102    TH1F *he=(TH1F*)gROOT->FindObject("he");
 103    if (!he)
 104       he =new TH1F("he","dE/dX for pions with 0.4<p<0.5 GeV/c",50,0.,100.);
 105
 106    TH2F *hep=(TH2F*)gROOT->FindObject("hep");
 107    if (!hep) hep=new TH2F("hep","dE/dX vs momentum",50,0.,2.,50,0.,400.);
 108    hep->SetMarkerStyle(8);
 109    hep->SetMarkerSize(0.4);
 110
 111
 112    Char_t fname[100];
 113    sprintf(fname,"%s/GoodTracksTPC.root",dir);
 114
 115    TFile *refFile=TFile::Open(fname,"old");
 116    if (!refFile || !refFile->IsOpen()) {
 117      ::Info("AliTPCUComparison.C","Marking good tracks (will take a while)...");
 118      if (GoodTracksTPC(dir)) {
 119         ::Error("AliTPCUComparison.C","Can't generate the reference file !");
 120         return 1;
 121      }
 122    }
 123    refFile=TFile::Open(fname,"old");
 124    if (!refFile || !refFile->IsOpen()) {
 125      ::Error("AliTPCUComparison.C","Can't open the reference file !");
 126      return 2;
 127    }
 128
 129    TTree *tpcTree=(TTree*)refFile->Get("tpcTree");
 130    if (!tpcTree) {
 131      ::Error("AliTPCUComparison.C","Can't get the reference tree !");
 132      return 3;
 133    }
 134    TBranch *branch=tpcTree->GetBranch("TPC");
 135    if (!branch) {
 136      ::Error("AliTPCUComparison.C","Can't get the TPC branch !");
 137      return 4;
 138    }
 139    TClonesArray dummy("AliTrackReference",1000), *refs=&dummy;
 140    branch->SetAddress(&refs);
 141
 142
 143    sprintf(fname,"%s/AliESDs.root",dir);
 144    TFile *ef=TFile::Open(fname);
 145    if ((!ef)||(!ef->IsOpen())) {
 146       sprintf(fname,"%s/AliESDtpc.root",dir);
 147       ef=TFile::Open(fname);
 148       if ((!ef)||(!ef->IsOpen())) {
 149          ::Error("AliTPCUComparison.C","Can't open AliESDtpc.root !");
 150          return 5;
 151       }
 152    }
 153    AliESDEvent* event = new AliESDEvent();
 154    TTree* esdTree = (TTree*) ef->Get("esdTree");
 155    if (!esdTree) {
 156       ::Error("AliTPCUComparison.C", "no ESD tree found");
 157       return 6;
 158    }
 159    event->ReadFromTree(esdTree);
 160
 161
 162    //******* Loop over events *********
 163    Int_t e=0;
 164    while (esdTree->GetEvent(e)) {
 165       cout<<endl<<endl<<"********* Processing event number: "<<e<<"*******\n";
 166
 167       Int_t nentr=event->GetNumberOfTracks();
 168       allfound+=nentr;
 169
 170       if (tpcTree->GetEvent(e++)==0) {
 171          cerr<<"No reconstructable tracks !\n";
 172          continue;
 173       }
 174
 175       Int_t ngood=refs->GetEntriesFast();
 176       allgood+=ngood;
 177
 178       const Int_t MAX=15000;
 179     //MI change
 180       Int_t track_notfound[MAX], itrack_notfound=0;
 181       Int_t track_fake[MAX], itrack_fake=0;
 182       Int_t track_multifound[MAX],track_multifound_n[MAX],itrack_multifound=0;
 183
 184       Int_t i;
 185       for (Int_t k=0; k<ngood; k++) {
 186         AliTrackReference *ref=(AliTrackReference*)refs->UncheckedAt(k);
 187         Int_t lab=ref->Label(), tlab=-1;
 188         Float_t ptg=TMath::Sqrt(ref->Px()*ref->Px() + ref->Py()*ref->Py());
 189
 190         if (ptg<1e-33) continue; // for those not crossing 0 pad row
 191
 192         if (ptg<ptcutl) continue;
 193         if (ptg>ptcuth) continue;
 194
 195         allselected++;
 196
 197         hgood->Fill(ptg);
 198
 199         AliESDtrack *track=0;
 200         for (i=0; i<nentr; i++) {
 201           track=event->GetTrack(i);
 202           tlab=track->GetTPCLabel();
 203           if (lab==TMath::Abs(tlab)) break;
 204         }
 205         if (i==nentr) {
 206            track_notfound[itrack_notfound++]=lab;
 207            continue;
 208         }
 209
 210         //MI change  - addition
 211         Int_t micount=0;
 212         Int_t mi;
 213         AliESDtrack * mitrack;
 214         for (mi=0; mi<nentr; mi++) {
 215           mitrack=event->GetTrack(mi);
 216           if (lab==TMath::Abs(mitrack->GetTPCLabel())) micount++;
 217         }
 218         if (micount>1) {
 219           track_multifound[itrack_multifound]=lab;
 220           track_multifound_n[itrack_multifound]=micount;
 221           itrack_multifound++;
 222         }
 223         if ((track->GetStatus()&AliESDtrack::kTPCrefit)==0) continue;
 224         if (lab==tlab) hfound->Fill(ptg);
 225         else {
 226           track_fake[itrack_fake++]=lab;
 227           hfake->Fill(ptg);
 228         }
 229
 230         Double_t pxpypz[3]; track->GetInnerPxPyPz(pxpypz);
 231         Float_t phi=TMath::ATan2(pxpypz[1],pxpypz[0]);
 232         if (phi<-TMath::Pi()) phi+=2*TMath::Pi();
 233         if (phi>=TMath::Pi()) phi-=2*TMath::Pi();
 234         Double_t pt=TMath::Sqrt(pxpypz[0]*pxpypz[0]+pxpypz[1]*pxpypz[1]);
 235         Float_t lam=TMath::ATan2(pxpypz[2],pt);
 236         Float_t pt_1=1/pt;
 237
 238         Int_t pdg=(Int_t)ref->GetLength();  //this is particle's PDG !
 239
 240         if (TMath::Abs(pdg)==11 && ptg>4.) {//high momentum electrons
 241            hmpt->Fill((pt_1 - 1/ptg)/(1/ptg)*100.);
 242         } else {
 243            Float_t phig=TMath::ATan2(ref->Py(),ref->Px());
 244            hp->Fill((phi - phig)*1000.);
 245
 246            Float_t lamg=TMath::ATan2(ref->Pz(),ptg);
 247            hl->Fill((lam - lamg)*1000.);
 248
 249            hpt->Fill((pt_1 - 1/ptg)/(1/ptg)*100.);
 250         }
 251
 252         Float_t mom=pt/TMath::Cos(lam);
 253         Float_t dedx=track->GetTPCsignal();
 254         hep->Fill(mom,dedx,1.);
 255         if (TMath::Abs(pdg)==211) //pions
 256            if (mom>0.4 && mom<0.5) {
 257               he->Fill(dedx,1.);
 258            }
 259       }
 260
 261       cout<<"\nList of Not found tracks :\n";
 262       for ( i = 0; i< itrack_notfound; i++){
 263         cout<<track_notfound[i]<<"\t";
 264         if ((i%5)==4) cout<<"\n";
 265       }
 266       cout<<"\nList of fake  tracks :\n";
 267       for ( i = 0; i< itrack_fake; i++){
 268         cout<<track_fake[i]<<"\t";
 269         if ((i%5)==4) cout<<"\n";
 270       }
 271       cout<<"\nList of multiple found tracks :\n";
 272       for ( i=0; i<itrack_multifound; i++) {
 273           cout<<"id.   "<<track_multifound[i]
 274               <<"     found - "<<track_multifound_n[i]<<"times\n";
 275       }
 276
 277       cout<<"Number of found tracks ="<<nentr<<endl;
 278       cout<<"Number of \"good\" tracks ="<<ngood<<endl;
 279
 280       refs->Clear();
 281   }// ***** End of the loop over events
 282
 283    delete event;
 284    delete esdTree;
 285    ef->Close();
 286
 287    delete tpcTree;
 288    refFile->Close();
 289
 290    Stat_t ng=hgood->GetEntries(), nf=hfound->GetEntries();
 291    if (ng!=0) cout<<"\n\nIntegral efficiency is about "<<nf/ng*100.<<" %\n";
 292    cout<<"Total number selected of \"good\" tracks ="<<allselected<<endl<<endl;
 293    cout<<"Total number of found tracks ="<<allfound<<endl;
 294    cout<<"Total number of \"good\" tracks ="<<allgood<<endl;
 295    cout<<endl;
 296
 297    gStyle->SetOptStat(111110);
 298    gStyle->SetOptFit(1);
 299
 300    TCanvas *c1=new TCanvas("c1","",0,0,700,850);
 301
 302    Int_t minc=33;
 303
 304    TPad *p1=new TPad("p1","",0,0.3,.5,.6); p1->Draw();
 305    p1->cd(); p1->SetFillColor(42); p1->SetFrameFillColor(10);
 306    hp->SetFillColor(4);  hp->SetXTitle("(mrad)");
 307    if (hp->GetEntries()<minc) hp->Draw(); else hp->Fit("gaus"); c1->cd();
 308
 309    TPad *p2=new TPad("p2","",0.5,.3,1,.6); p2->Draw();
 310    p2->cd(); p2->SetFillColor(42); p2->SetFrameFillColor(10);
 311    hl->SetXTitle("(mrad)");
 312    if (hl->GetEntries()<minc) hl->Draw(); else hl->Fit("gaus"); c1->cd();
 313
 314    TPad *p3=new TPad("p3","",0,0,0.5,0.3); p3->Draw();
 315    p3->cd(); p3->SetFillColor(42); p3->SetFrameFillColor(10);
 316    hpt->SetXTitle("(%)");
 317    if (hpt->GetEntries()<minc) hpt->Draw(); else hpt->Fit("gaus"); c1->cd();
 318
 319    TPad *p4=new TPad("p4","",0.5,0,1,0.3); p4->Draw();
 320    p4->cd(); p4->SetFillColor(42); p4->SetFrameFillColor(10);
 321    hmpt->SetXTitle("(%)");
 322    if (hmpt->GetEntries()<minc) hmpt->Draw(); else hmpt->Fit("gaus"); c1->cd();
 323
 324    TPad *p5=new TPad("p5","",0,0.6,1,1); p5->Draw(); p5->cd();
 325    p5->SetFillColor(41); p5->SetFrameFillColor(10);
 326    hfound->Sumw2(); hgood->Sumw2(); hfake->Sumw2();
 327    hg->Divide(hfound,hgood,1,1.,"b");
 328    hf->Divide(hfake,hgood,1,1.,"b");
 329    hg->SetMaximum(1.4);
 330    hg->SetYTitle("Tracking efficiency");
 331    hg->SetXTitle("Pt (GeV/c)");
 332    hg->Draw();
 333
 334    TLine *line1 = new TLine(ptcutl,1.0,ptcuth,1.0); line1->SetLineStyle(4);
 335    line1->Draw("same");
 336    TLine *line2 = new TLine(ptcutl,0.9,ptcuth,0.9); line2->SetLineStyle(4);
 337    line2->Draw("same");
 338
 339    hf->SetFillColor(1);
 340    hf->SetFillStyle(3013);
 341    hf->SetLineColor(2);
 342    hf->SetLineWidth(2);
 343    hf->Draw("histsame");
 344    TText *text = new TText(0.461176,0.248448,"Fake tracks");
 345    text->SetTextSize(0.05);
 346    text->Draw();
 347    text = new TText(0.453919,1.11408,"Good tracks");
 348    text->SetTextSize(0.05);
 349    text->Draw();
 350
 351
 352
 353    TCanvas *c2=new TCanvas("c2","",320,32,530,590);
 354
 355    TPad *p6=new TPad("p6","",0.,0.,1.,.5); p6->Draw();
 356    p6->cd(); p6->SetFillColor(42); p6->SetFrameFillColor(10);
 357    he->SetFillColor(2); he->SetFillStyle(3005);
 358    he->SetXTitle("Arbitrary Units");
 359    if (he->GetEntries()<minc) he->Draw(); else he->Fit("gaus"); c2->cd();
 360
 361    TPad *p7=new TPad("p7","",0.,0.5,1.,1.); p7->Draw();
 362    p7->cd(); p7->SetFillColor(42); p7->SetFrameFillColor(10);
 363    hep->SetXTitle("p (Gev/c)"); hep->SetYTitle("dE/dX (Arb. Units)");
 364    hep->Draw(); c1->cd();
 365
 366    TFile fc("AliTPCUComparison.root","RECREATE");
 367    c1->Write();
 368    c2->Write();
 369    fc.Close();
 370
 371    gBenchmark->Stop("AliTPCUComparison");
 372    gBenchmark->Show("AliTPCUComparison");
 373
 374    return 0;
 375 }
 376
 377
 378 Int_t GoodTracksTPC(const Char_t *dir) {
 379    Char_t fname[100];
 380    sprintf(fname,"%s/galice.root",dir);
 381
 382    AliRunLoader *rl = AliRunLoader::Open(fname,"COMPARISON");
 383    if (!rl) {
 384       ::Error("GoodTracksTPC","Can't start session !");
 385       return 1;
 386    }
 387
 388    rl->LoadgAlice();
 389    rl->LoadHeader();
 390    rl->LoadKinematics();
 391    rl->LoadTrackRefs();
 392
 393    AliTPCLoader *tpcl = (AliTPCLoader *)rl->GetLoader("TPCLoader");
 394    if (tpcl == 0x0) {
 395       ::Error("GoodTracksTPC","Can not find TPCLoader !");
 396       delete rl;
 397       return 2;
 398    }
 399
 400    AliTPC *TPC=(AliTPC*)rl->GetAliRun()->GetDetector("TPC");
 401    Int_t ver = TPC->IsVersion();
 402    cout<<"TPC version "<<ver<<" has been found !\n";
 403    if (ver==1) tpcl->LoadRecPoints();
 404    else if (ver==2) tpcl->LoadDigits();
 405    else {
 406       ::Error("GoodTracksTPC","Wrong TPC version !");
 407       delete rl;
 408       return 3;
 409    }
 410
 411   TGeoGlobalMagField::Instance()->SetField(
 412   new AliMagF("Maps","Maps", -1., -1., AliMagF::k5kG));
 413
 414    AliCDBManager *man=AliCDBManager::Instance();
 415    man->SetDefaultStorage("local://$ALICE_ROOT/OCDB");
 416    man->SetRun(0);
 417    AliTPCParamSR *digp=
 418    (AliTPCParamSR*)(AliTPCcalibDB::Instance()->GetParameters());
 419    if (!digp) {
 420      ::Error("AliTPCUComparison.C","TPC parameters have not been found !");
 421      delete rl;
 422      return 4;
 423    }
 424
 425    Int_t nrow_up=digp->GetNRowUp();
 426    Int_t nrows=digp->GetNRowLow()+nrow_up;
 427    Int_t zero=digp->GetZeroSup();
 428    Int_t gap=Int_t(0.125*nrows), shift=Int_t(0.5*gap);
 429    Int_t good_number=Int_t(0.4*nrows);
 430
 431    Int_t nev=rl->GetNumberOfEvents();
 432    ::Info("GoodTracksTPC","Number of events : %d\n",nev);
 433
 434
 435    sprintf(fname,"%s/GoodTracksTPC.root",dir);
 436    TFile *file=TFile::Open(fname,"recreate");
 437
 438    TClonesArray dummy("AliTrackReference",1000), *refs=&dummy;
 439    TTree tpcTree("tpcTree","Tree with info about the reconstructable TPC tracks");
 440    tpcTree.Branch("TPC",&refs);
 441
 442    //********  Loop over generated events
 443    for (Int_t e=0; e<nev; e++) {
 444      Int_t nt=0;
 445      refs->Clear();
 446
 447      Int_t i;
 448
 449      rl->GetEvent(e);  file->cd();
 450
 451      Int_t np = rl->GetHeader()->GetNtrack();
 452      cout<<"Event "<<e<<" Number of particles: "<<np<<endl;
 453
 454      //******** Fill the "good" masks
 455      Int_t *good=new Int_t[np]; for (i=0; i<np; i++) good[i]=0;
 456      switch (ver) {
 457      case 1:
 458        /*
 459         {
 460         AliTPCClustersArray *pca=new AliTPCClustersArray, &ca=*pca;
 461         ca.Setup(digp);
 462         ca.SetClusterType("AliTPCcluster");
 463         ca.ConnectTree(tpcl->TreeR());
 464         Int_t nrows=Int_t(ca.GetTree()->GetEntries());
 465         for (Int_t n=0; n<nrows; n++) {
 466           AliSegmentID *s=ca.LoadEntry(n);
 467           Int_t sec,row;
 468           digp->AdjustSectorRow(s->GetID(),sec,row);
 469           AliTPCClustersRow &clrow = *ca.GetRow(sec,row);
 470           Int_t ncl=clrow.GetArray()->GetEntriesFast();
 471           while (ncl--) {
 472               AliTPCcluster *c=(AliTPCcluster*)clrow[ncl];
 473               Int_t lab=c->GetLabel(0);
 474               if (lab<0) continue; //noise cluster
 475               lab=TMath::Abs(lab);
 476
 477               if (sec>=digp->GetNInnerSector())
 478                  if (row==nrow_up-1) good[lab]|=0x4000;
 479               if (sec>=digp->GetNInnerSector())
 480                  if (row==nrow_up-1-gap) good[lab]|=0x1000;
 481
 482               if (sec>=digp->GetNInnerSector())
 483                  if (row==nrow_up-1-shift) good[lab]|=0x2000;
 484               if (sec>=digp->GetNInnerSector())
 485                  if (row==nrow_up-1-gap-shift) good[lab]|=0x800;
 486
 487               good[lab]++;
 488           }
 489           ca.ClearRow(sec,row);
 490         }
 491         delete pca;
 492         }
 493         break;
 494        */
 495      case 2:
 496         {
 497         TTree *TD=tpcl->TreeD();
 498
 499         AliSimDigits da, *digits=&da;
 500         TD->GetBranch("Segment")->SetAddress(&digits);
 501
 502         Int_t *count = new Int_t[np];
 503         Int_t i;
 504         for (i=0; i<np; i++) count[i]=0;
 505
 506         Int_t sectors_by_rows=(Int_t)TD->GetEntries();
 507         for (i=0; i<sectors_by_rows; i++) {
 508           if (!TD->GetEvent(i)) continue;
 509           Int_t sec,row;
 510           digp->AdjustSectorRow(digits->GetID(),sec,row);
 511           //cerr<<sec<<' '<<row<<'\r';
 512           digits->First();
 513           do { //Many thanks to J.Chudoba who noticed this
 514               Int_t it=digits->CurrentRow(), ip=digits->CurrentColumn();
 515               Short_t dig = digits->GetDigit(it,ip);
 516               Int_t idx0=digits->GetTrackID(it,ip,0);
 517               Int_t idx1=digits->GetTrackID(it,ip,1);
 518               Int_t idx2=digits->GetTrackID(it,ip,2);
 519               if (idx0>=0 && dig>=zero && idx0<np) count[idx0]+=1;
 520               if (idx1>=0 && dig>=zero && idx1<np) count[idx1]+=1;
 521               if (idx2>=0 && dig>=zero && idx2<np) count[idx2]+=1;
 522           } while (digits->Next());
 523           for (Int_t j=0; j<np; j++) {
 524               if (count[j]>1) {
 525                  if (sec>=digp->GetNInnerSector())
 526                    if (row==nrow_up-1    ) good[j]|=0x4000;
 527                  if (sec>=digp->GetNInnerSector())
 528                    if (row==nrow_up-1-gap) good[j]|=0x1000;
 529
 530                  if (sec>=digp->GetNInnerSector())
 531                    if (row==nrow_up-1-shift) good[j]|=0x2000;
 532                  if (sec>=digp->GetNInnerSector())
 533                    if (row==nrow_up-1-gap-shift) good[j]|=0x800;
 534                  good[j]++;
 535               }
 536               count[j]=0;
 537           }
 538         }
 539         delete[] count;
 540         }
 541         break;
 542      }
 543
 544
 545      //****** select tracks which are "good" enough
 546      AliStack* stack = rl->Stack();
 547      for (i=0; i<np; i++) {
 548         if ((good[i]&0x5000) != 0x5000)
 549         if ((good[i]&0x2800) != 0x2800) continue;
 550         if ((good[i]&0x7FF ) < good_number) continue;
 551         TParticle *p = (TParticle*)stack->Particle(i);
 552         if (p == 0x0) {
 553          cerr<<"Can not get particle "<<i<<endl;
 554          continue;
 555         }
 556         if (p->Pt() <= 0.) continue;
 557         if (TMath::Abs(p->Pz()/p->Pt())>0.999) continue;
 558
 559         Double_t vx=p->Vx(),vy=p->Vy(),vz=p->Vz();
 560         if (TMath::Sqrt(vx*vx+vy*vy)>3.5) continue;
 561         if (TMath::Abs(vz) > 50.) continue;
 562
 563         AliTrackReference *ref=new((*refs)[nt]) AliTrackReference();
 564
 565         ref->SetLabel(i);
 566         Int_t pdg=p->GetPdgCode();
 567         ref->SetLength(pdg);  //This will the particle's PDG !
 568         ref->SetMomentum(0.,0.,0.);
 569         ref->SetPosition(0.,0.,0.);
 570
 571         nt++;
 572      }
 573
 574      //**** check if there is also information at the entrance of the TPC
 575      TTree *TR=rl->TreeTR();
 576      TBranch *branch=TR->GetBranch("TrackReferences");
 577      if (branch==0) {
 578         ::Error("GoodTracksTPC","No track references !");
 579         delete rl;
 580         return 5;
 581      }
 582      TClonesArray tpcdummy("AliTrackReference",1000), *tpcRefs=&tpcdummy;
 583      branch->SetAddress(&tpcRefs);
 584      Int_t nr=(Int_t)TR->GetEntries();
 585      for (Int_t r=0; r<nr; r++) {
 586          //cerr<<r<<' '<<nr<<'\r';
 587          TR->GetEvent(r);
 588
 589          Int_t nref = tpcRefs->GetEntriesFast();
 590          if (!nref) continue;
 591          AliTrackReference *tpcRef= 0x0;
 592          for (Int_t iref=0; iref<nref; ++iref) {
 593            tpcRef = (AliTrackReference*)tpcRefs->UncheckedAt(iref);
 594            if (tpcRef->DetectorId() == AliTrackReference::kTPC) break;
 595            tpcRef = 0x0;
 596          }
 597
 598          if (!tpcRef) continue;
 599
 600          Int_t j;
 601          AliTrackReference *ref=0;
 602          for (j=0; j<nt; j++) {
 603            ref=(AliTrackReference *)refs->UncheckedAt(j);
 604            if (ref->Label()==tpcRef->Label()) break;
 605            ref=0;
 606          }
 607          if (ref==0) continue;
 608
 609          ref->SetMomentum(tpcRef->Px(),tpcRef->Py(),tpcRef->Pz());
 610          ref->SetPosition(tpcRef->LocalX(),tpcRef->LocalY(),tpcRef->Z());
 611
 612          tpcRefs->Clear();
 613      }
 614
 615      tpcTree.Fill();
 616
 617      delete[] good;
 618    } //****** end of the loop over generated events
 619
 620
 621    tpcTree.Write();
 622    file->Close();
 623
 624    delete rl;
 625    return 0;
 626 }