PWG1/AliComparisonDCA.cxx

   1 //------------------------------------------------------------------------------
   2 // Implementation of AliComparisonDCA class. It keeps information from
   3 // comparison of reconstructed and MC particle tracks. In addtion,
   4 // it keeps selection cuts used during comparison. The comparison
   5 // information is stored in the ROOT histograms. Analysis of these
   6 // histograms can be done by using Analyse() class function. The result of
   7 // the analysis (histograms/graphs) are stored in the folder
   8 // which is a data member of AliComparisonDCA.
   9 //
  10 // Author: J.Otwinowski 04/02/2008
  11 //------------------------------------------------------------------------------
  12
  13 /*
  14
  15   // after running comparison task, read the file, and get component
  16   gROOT->LoadMacro("$ALICE_ROOT/PWG1/Macros/LoadMyLibs.C");
  17   LoadMyLibs();
  18   TFile f("Output.root");
  19   //AliComparisonDCA * compObj = (AliComparisonDCA*)f.Get("AliComparisonDCA");
  20   AliComparisonDCA * compObj = (AliComparisonDCA*)cOutput->FindObject("AliComparisonDCA");
  21
  22   // Analyse comparison data
  23   compObj->Analyse();
  24
  25   // the output histograms/graphs will be stored in the folder "folderDCA"
  26   compObj->GetAnalysisFolder()->ls("*");
  27
  28   // user can save whole comparison object (or only folder with anlysed histograms)
  29   // in the seperate output file (e.g.)
  30   TFile fout("Analysed_DCA.root","recreate");
  31   compObj->Write(); // compObj->GetAnalysisFolder()->Write();
  32   fout.Close();
  33
  34 */
  35
  36 #include <iostream>
  37
  38 #include "TFile.h"
  39 #include "TH3F.h"
  40 #include "TH2F.h"
  41 #include "TF1.h"
  42 #include "TProfile.h"
  43 #include "TProfile2D.h"
  44 #include "TGraph2D.h"
  45 #include "TCanvas.h"
  46 #include "TGraph.h"
  47 //
  48 #include "AliTracker.h"
  49 #include "AliESDEvent.h"
  50 #include "AliESD.h"
  51 #include "AliESDfriend.h"
  52 #include "AliESDfriendTrack.h"
  53 #include "AliRecInfoCuts.h"
  54 #include "AliMCInfoCuts.h"
  55 #include "AliLog.h"
  56 #include "AliESDVertex.h"
  57 //
  58 #include "AliMathBase.h"
  59 #include "AliTreeDraw.h"
  60
  61 #include "AliMCInfo.h"
  62 #include "AliESDRecInfo.h"
  63 #include "AliComparisonDCA.h"
  64
  65 using namespace std;
  66
  67 ClassImp(AliComparisonDCA)
  68
  69 //_____________________________________________________________________________
  70 AliComparisonDCA::AliComparisonDCA():
  71   AliComparisonObject("AliComparisonDCA"),
  72
  73   // DCA histograms
  74   fD0TanSPtTPCITS(0),
  75   fD1TanSPtTPCITS(0),
  76   fD0TanSPt(0),
  77   fD1TanSPt(0),
  78   fD0TanSPtTPC(0),
  79   fD1TanSPtTPC(0),
  80
  81   // Cuts
  82   fCutsRC(0),
  83   fCutsMC(0),
  84
  85   // histogram folder
  86   fAnalysisFolder(0)
  87 {
  88   Init();
  89 }
  90
  91 //_____________________________________________________________________________
  92 AliComparisonDCA::~AliComparisonDCA()
  93 {
  94   //
  95   if(fD0TanSPtTPCITS) delete fD0TanSPtTPCITS; fD0TanSPtTPCITS=0;
  96   if(fD1TanSPtTPCITS) delete fD1TanSPtTPCITS; fD1TanSPtTPCITS=0;
  97   if(fD0TanSPt) delete fD0TanSPt; fD0TanSPt=0;
  98   if(fD1TanSPt) delete fD1TanSPt; fD1TanSPt=0;
  99   if(fD0TanSPtTPC) delete fD0TanSPtTPC; fD0TanSPtTPC=0;
 100   if(fD1TanSPtTPC) delete fD1TanSPtTPC; fD1TanSPtTPC=0;
 101   if(fAnalysisFolder) delete fAnalysisFolder; fAnalysisFolder=0;
 102
 103 }
 104
 105 //_____________________________________________________________________________
 106 void AliComparisonDCA::Init()
 107 {
 108   // DCA histograms
 109   fD0TanSPtTPCITS = new TH3F("DCAyTanSPtTPCITS","DCAyTanSPt",40,-2,2, 10,0.3,3, 100,-1,1);
 110   fD0TanSPtTPCITS->SetXTitle("tan(#theta)");
 111   fD0TanSPtTPCITS->SetYTitle("#sqrt{p_{t}(GeV)}");
 112   fD0TanSPtTPCITS->SetZTitle("DCA_{xy}");
 113
 114   fD1TanSPtTPCITS = new TH3F("DCAzTanSPtTPCITS","DCAzTanSPt",40,-2,2, 10,0.3,3, 100,-1,1);
 115   fD1TanSPtTPCITS->SetXTitle("tan(#theta)");
 116   fD1TanSPtTPCITS->SetYTitle("#sqrt(p_{t}(GeV))");
 117   fD1TanSPtTPCITS->SetZTitle("DCA_{z}");
 118
 119   fD0TanSPt = new TH3F("DCAyTanSPt","DCAyTanSPt",40,-2,2, 10,0.3,3, 100,-1,1);
 120   fD0TanSPt->SetXTitle("tan(#theta)");
 121   fD0TanSPt->SetYTitle("#sqrt{p_{t}(GeV)}");
 122   fD0TanSPt->SetZTitle("DCA_{xy}");
 123
 124   fD1TanSPt = new TH3F("DCAzTanSPt","DCAzTanSPt",40,-2,2, 10,0.3,3, 100, -1,1);
 125   fD1TanSPt->SetXTitle("tan(#theta)");
 126   fD1TanSPt->SetYTitle("#sqrt{p_{t}(GeV)}");
 127   fD1TanSPt->SetZTitle("DCA_{z}");
 128
 129   fD0TanSPtTPC = new TH3F("DCAyTanSPtTPC","DCAyTanSPt",40,-2,2, 10,0.3,3, 100,-1,1);
 130   fD0TanSPtTPC->SetXTitle("tan(#theta)");
 131   fD0TanSPtTPC->SetYTitle("#sqrt{p_{t}(GeV)}");
 132   fD0TanSPtTPC->SetZTitle("DCA_{xy}");
 133
 134   fD1TanSPtTPC = new TH3F("DCAzTanSPtTPC","DCAzTanSPt",40,-2,2, 10,0.3,3, 100, -1,1);
 135   fD1TanSPtTPC->SetXTitle("tan(#theta)");
 136   fD1TanSPtTPC->SetYTitle("#sqrt{p_{t}(GeV)}");
 137   fD1TanSPtTPC->SetZTitle("DCA_{z}");
 138
 139   // init cuts
 140   if(!fCutsMC)
 141     AliDebug(AliLog::kError, "ERROR: Cannot find AliMCInfoCuts object");
 142   if(!fCutsRC)
 143     AliDebug(AliLog::kError, "ERROR: Cannot find AliRecInfoCuts object");
 144
 145   // init folder
 146   fAnalysisFolder = CreateFolder("folderDCA","Analysis DCA Folder");
 147 }
 148
 149 //_____________________________________________________________________________
 150 void AliComparisonDCA::Process(AliMCInfo* infoMC, AliESDRecInfo *infoRC)
 151 {
 152   // Fill DCA comparison information
 153   AliExternalTrackParam *track = 0;
 154   Double_t field      = AliTracker::GetBz(); // nominal Bz field [kG]
 155   Double_t kMaxD      = 123456.0; // max distance
 156
 157   Int_t clusterITS[200];
 158   Double_t dca[2], cov[3]; // dca_xy, dca_z, sigma_xy, sigma_xy_z, sigma_z
 159   Float_t dca1[2], cov1[3]; // dca_xy, dca_z, sigma_xy, sigma_xy_z, sigma_z
 160
 161   Float_t mcpt = infoMC->GetParticle().Pt();
 162   Float_t tantheta = TMath::Tan(infoMC->GetParticle().Theta()-TMath::Pi()*0.5);
 163   Float_t spt = TMath::Sqrt(mcpt);
 164
 165   // distance to Prim. vertex
 166   const Double_t* dv = infoMC->GetVDist();
 167
 168   Bool_t isPrim = TMath::Sqrt(dv[0]*dv[0] + dv[1]*dv[1])<fCutsMC->GetMaxR() && TMath::Abs(dv[2])<fCutsMC->GetMaxVz();
 169
 170   // Check selection cuts
 171   if (fCutsMC->IsPdgParticle(TMath::Abs(infoMC->GetParticle().GetPdgCode())) == kFALSE) return;
 172   if (!isPrim) return;
 173   if (infoRC->GetStatus(1)!=3) return;
 174   if (!infoRC->GetESDtrack()) return;
 175   if (infoRC->GetESDtrack()->GetTPCNcls()<fCutsRC->GetMinNClustersTPC()) return;
 176   if (!infoRC->GetESDtrack()->GetConstrainedParam()) return;
 177
 178   // calculate and set prim. vertex
 179   AliESDVertex vertexMC;
 180   vertexMC.SetXv( infoMC->GetParticle().Vx() - dv[0] );
 181   vertexMC.SetYv( infoMC->GetParticle().Vy() - dv[1] );
 182   vertexMC.SetZv( infoMC->GetParticle().Vz() - dv[2] );
 183
 184   // calculate track parameters at vertex
 185   if (infoRC->GetESDtrack()->GetTPCInnerParam())
 186   {
 187     if ((track = new AliExternalTrackParam(*infoRC->GetESDtrack()->GetTPCInnerParam())) != 0 )
 188     {
 189       Bool_t bDCAStatus = track->PropagateToDCA(&vertexMC,field,kMaxD,dca,cov);
 190
 191       if(bDCAStatus) {
 192         fD0TanSPtTPC->Fill(tantheta,spt,dca[0]);
 193         fD1TanSPtTPC->Fill(tantheta,spt,dca[1]);
 194           }
 195
 196           delete track;
 197     }
 198   }
 199
 200  infoRC->GetESDtrack()->GetImpactParameters(dca1,cov1);
 201
 202  // ITS + TPC
 203  if(infoRC->GetESDtrack()->GetITSclusters(clusterITS)>fCutsRC->GetMinNClustersITS()){
 204     fD0TanSPtTPCITS->Fill(tantheta,spt,dca1[0]);
 205     fD1TanSPtTPCITS->Fill(tantheta,spt,dca1[1]);
 206   }
 207     fD0TanSPt->Fill(tantheta,spt,dca1[0]);
 208     fD1TanSPt->Fill(tantheta,spt,dca1[1]);
 209 }
 210
 211 //_____________________________________________________________________________
 212 Long64_t AliComparisonDCA::Merge(TCollection* list)
 213 {
 214   // Merge list of objects (needed by PROOF)
 215
 216   if (!list)
 217   return 0;
 218
 219   if (list->IsEmpty())
 220   return 1;
 221
 222   TIterator* iter = list->MakeIterator();
 223   TObject* obj = 0;
 224
 225   // collection of generated histograms
 226   Int_t count=0;
 227   while((obj = iter->Next()) != 0)
 228   {
 229     AliComparisonDCA* entry = dynamic_cast<AliComparisonDCA*>(obj);
 230     if (entry == 0) continue;
 231
 232
 233     fD0TanSPtTPCITS->Add(entry->fD0TanSPtTPCITS);
 234     fD1TanSPtTPCITS->Add(entry->fD1TanSPtTPCITS);
 235     fD0TanSPt->Add(entry->fD0TanSPt);
 236     fD1TanSPt->Add(entry->fD1TanSPt);
 237     fD0TanSPtTPC->Add(entry->fD0TanSPtTPC);
 238     fD1TanSPtTPC->Add(entry->fD1TanSPtTPC);
 239
 240     count++;
 241   }
 242
 243 return count;
 244 }
 245
 246 //_____________________________________________________________________________
 247 void AliComparisonDCA::Exec(AliMCInfo* infoMC, AliESDRecInfo *infoRC){
 248   // Process comparison information
 249   Process(infoMC,infoRC);
 250 }
 251
 252 //_____________________________________________________________________________
 253 void AliComparisonDCA::Analyse()
 254 {
 255   //
 256   // Analyse comparison information and store output histograms
 257   // in the analysis folder "folderDCA"
 258   //
 259
 260   TH1::AddDirectory(kFALSE);
 261
 262   TGraph * gr[8]= { 0,0,0,0,0,0,0,0 };
 263   TGraph2D *gr2[8]= { 0,0,0,0,0,0,0,0};
 264   AliComparisonDCA * comp=this;
 265   TObjArray *aFolderObj = new TObjArray;
 266
 267   // write results in the folder
 268   // Canvas to draw analysed histograms
 269   TCanvas * c = new TCanvas("canDCA","DCA resolution");
 270   c->Divide(2,4);
 271   //
 272   // DCA resolution
 273   //
 274   c->cd(1);
 275   gr[0] = AliMathBase::MakeStat1D(comp->fD0TanSPtTPC,2,5);
 276   gr[0]->GetXaxis()->SetTitle("Tan(#theta)");
 277   gr[0]->GetYaxis()->SetTitle("#sigmaDCA_xy (cm)");
 278   gr[0]->SetName("DCAXYResolTanTPC");
 279   gr[0]->SetTitle("resol. DCA_xy (TPC only)");
 280   gr[0]->Draw("Al*");
 281
 282   aFolderObj->Add(gr[0]);
 283
 284   c->cd(2);
 285   gr[1] = AliMathBase::MakeStat1D(comp->fD1TanSPtTPC,2,5);
 286   gr[1]->GetXaxis()->SetTitle("Tan(#theta)");
 287   gr[1]->GetYaxis()->SetTitle("#sigmaDCA_z (cm)");
 288   gr[1]->SetName("DCAZResolTanTPC");
 289   gr[1]->SetTitle("resol. DCA_z (TPC only)");
 290   gr[1]->Draw("Al*");
 291
 292   aFolderObj->Add(gr[1]);
 293
 294   c->cd(3);
 295   gr[2] = AliMathBase::MakeStat1D(comp->fD0TanSPtTPCITS,2,5);
 296   gr[2]->GetXaxis()->SetTitle("Tan(#theta)");
 297   gr[2]->GetYaxis()->SetTitle("#sigmaDCA_xy (cm)");
 298   gr[2]->SetName("DCAXYResolTanTPCITS");
 299   gr[2]->SetTitle("resol. DCA_xy (TPC+ITS)");
 300   gr[2]->Draw("Al*");
 301
 302   aFolderObj->Add(gr[2]);
 303
 304   c->cd(4);
 305   gr[3] = AliMathBase::MakeStat1D(comp->fD1TanSPtTPCITS,2,5);
 306   gr[3]->GetXaxis()->SetTitle("Tan(#theta)");
 307   gr[3]->GetYaxis()->SetTitle("#sigmaDCA_z (cm)");
 308   gr[3]->SetName("DCAZResolTanTPCITS");
 309   gr[3]->SetTitle("resol. DCA_z (TPC+ITS)");
 310   gr[3]->Draw("Al*");
 311
 312   aFolderObj->Add(gr[3]);
 313
 314   //
 315   // DCA mean value
 316   //
 317   c->cd(5);
 318   gr[4] = AliMathBase::MakeStat1D(comp->fD0TanSPtTPC,2,4);
 319   gr[4]->GetXaxis()->SetTitle("Tan(#theta)");
 320   gr[4]->GetYaxis()->SetTitle("mean DCA_xy (cm)");
 321   gr[4]->SetName("DCAXYMeanTanTPC");
 322   gr[4]->SetTitle("mean DCA_xy (TPC only)");
 323   gr[4]->Draw("Al*");
 324
 325   aFolderObj->Add(gr[4]);
 326
 327   c->cd(6);
 328   gr[5] = AliMathBase::MakeStat1D(comp->fD1TanSPtTPC,2,4);
 329   gr[5]->GetXaxis()->SetTitle("Tan(#theta)");
 330   gr[5]->GetYaxis()->SetTitle("mean DCA_z (cm)");
 331   gr[5]->SetName("DCAZMeanTanTPC");
 332   gr[5]->SetTitle("mean DCA_z (TPC only)");
 333   gr[5]->Draw("Al*");
 334
 335   aFolderObj->Add(gr[5]);
 336
 337   c->cd(7);
 338   gr[6] = AliMathBase::MakeStat1D(comp->fD0TanSPtTPCITS,2,4);
 339   gr[6]->GetXaxis()->SetTitle("Tan(#theta)");
 340   gr[6]->GetYaxis()->SetTitle("mean DCA_xy (cm)");
 341   gr[6]->SetName("DCAXYMeanTanTPCITS");
 342   gr[6]->SetTitle("mean DCA_xy (TPC+ITS)");
 343   gr[6]->Draw("Al*");
 344
 345   aFolderObj->Add(gr[6]);
 346
 347   c->cd(8);
 348   gr[7] = AliMathBase::MakeStat1D(comp->fD1TanSPtTPCITS,2,4);
 349   gr[7]->GetXaxis()->SetTitle("Tan(#theta)");
 350   gr[7]->GetYaxis()->SetTitle("mean DCA_z (cm)");
 351   gr[7]->SetName("DCAZMeanTanTPCITS");
 352   gr[7]->SetTitle("mean DCA_z (TPC+ITS)");
 353   gr[7]->Draw("Al*");
 354
 355   aFolderObj->Add(gr[7]);
 356
 357   // 2D DCA resolution
 358   TCanvas * c1 = new TCanvas("canDCA1","2D DCA resolution");
 359   c1->Divide(2,4);
 360
 361   // TPC only
 362   c1->cd(1);
 363   gr2[0] = AliMathBase::MakeStat2D(comp->fD0TanSPtTPC,4,2,5);
 364   gr2[0]->GetXaxis()->SetTitle("Tan(#theta)");
 365   gr2[0]->GetYaxis()->SetTitle("#sqrt{p_{t}(GeV)}");
 366   gr2[0]->GetZaxis()->SetTitle("#sigmaDCA_xy (cm)");
 367   gr2[0]->SetName("DCAXYResolSPTTanTPC");
 368   gr2[0]->SetTitle("#sigma DCA_xy (TPC only)");
 369   gr2[0]->GetHistogram()->Draw("colz");
 370
 371   gr2[0]->GetHistogram()->SetName("DCAXYResolSPTTanTPC");
 372   aFolderObj->Add(gr2[0]->GetHistogram());
 373
 374   c1->cd(2);
 375   gr2[1] = AliMathBase::MakeStat2D(comp->fD1TanSPtTPC,4,2,5);
 376   gr2[1]->GetXaxis()->SetTitle("Tan(#theta)");
 377   gr2[1]->GetYaxis()->SetTitle("#sqrt{p_{t}(GeV)}");
 378   gr2[1]->GetZaxis()->SetTitle("#sigmaDCA_z (cm)");
 379   gr2[1]->SetName("DCAZResolSPTTanTPC");
 380   gr2[1]->SetTitle("#sigma DCA_z (TPC only)");
 381   gr2[1]->GetHistogram()->Draw("colz");
 382
 383   gr2[1]->GetHistogram()->SetName("DCAZResolSPTTanTPC");
 384   aFolderObj->Add(gr2[1]->GetHistogram());
 385
 386   // TPC+ITS
 387   c1->cd(3);
 388   gr2[2] = AliMathBase::MakeStat2D(comp->fD0TanSPtTPCITS,4,2,5);
 389   gr2[2]->GetXaxis()->SetTitle("Tan(#theta)");
 390   gr2[2]->GetYaxis()->SetTitle("#sqrt{p_{t}(GeV)}");
 391   gr2[2]->GetZaxis()->SetTitle("#sigmaDCA_xy (cm)");
 392   gr2[2]->SetName("DCAXYResolSPTTanTPCITS");
 393   gr2[2]->SetTitle("#sigma DCA_xy (TPC+ITS)");
 394   gr2[2]->GetHistogram()->Draw("colz");
 395
 396   gr2[2]->GetHistogram()->SetName("DCAXYResolSPTTanTPCITS");
 397   aFolderObj->Add(gr2[2]->GetHistogram());
 398
 399   c1->cd(4);
 400   gr2[3] = AliMathBase::MakeStat2D(comp->fD1TanSPtTPCITS,4,2,5);
 401   gr2[3]->GetXaxis()->SetTitle("Tan(#theta)");
 402   gr2[3]->GetYaxis()->SetTitle("#sqrt{p_{t}(GeV)}");
 403   gr2[3]->GetZaxis()->SetTitle("#sigmaDCA_z (cm)");
 404   gr2[3]->SetName("DCAZResolSPTTanTPCITS");
 405   gr2[3]->SetTitle("#sigma DCA_z (TPC+ITS)");
 406   gr2[3]->GetHistogram()->Draw("colz");
 407
 408   gr2[3]->GetHistogram()->SetName("DCAZResolSPTTanTPCITS");
 409   aFolderObj->Add(gr2[3]->GetHistogram());
 410
 411   // 2D DCA mean value
 412   c1->cd(5);
 413   gr2[4] = AliMathBase::MakeStat2D(comp->fD0TanSPtTPC,4,2,4);
 414   gr2[4]->GetXaxis()->SetTitle("Tan(#theta)");
 415   gr2[4]->GetYaxis()->SetTitle("#sqrt{p_{t}(GeV)}");
 416   gr2[4]->GetZaxis()->SetTitle("mean DCA_xy (cm)");
 417   gr2[4]->SetName("DCAXYMeanSPTTanTPC");
 418   gr2[4]->SetTitle("mean DCA_xy (TPC only)");
 419   gr2[4]->GetHistogram()->Draw("colz");
 420
 421   gr2[4]->GetHistogram()->SetName("DCAXYMeanSPTTanTPC");
 422   aFolderObj->Add(gr2[4]->GetHistogram());
 423
 424   c1->cd(6);
 425   gr2[5] = AliMathBase::MakeStat2D(comp->fD1TanSPtTPC,4,2,4);
 426   gr2[5]->GetXaxis()->SetTitle("Tan(#theta)");
 427   gr2[5]->GetYaxis()->SetTitle("#sqrt{p_{t}(GeV)}");
 428   gr2[5]->GetZaxis()->SetTitle("mean DCA_z (cm)");
 429   gr2[5]->SetName("DCAZMeanSPTTanTPC");
 430   gr2[5]->SetTitle("mean DCA_z (TPC only)");
 431   gr2[5]->GetHistogram()->Draw("colz");
 432
 433   gr2[5]->GetHistogram()->SetName("DCAZMeanSPTTanTPC");
 434   aFolderObj->Add(gr2[5]->GetHistogram());
 435
 436   c1->cd(7);
 437   gr2[6] = AliMathBase::MakeStat2D(comp->fD0TanSPtTPCITS,4,2,4);
 438   gr2[6]->GetXaxis()->SetTitle("Tan(#theta)");
 439   gr2[6]->GetYaxis()->SetTitle("#sqrt{p_{t}(GeV)}");
 440   gr2[6]->GetZaxis()->SetTitle("mean DCA_xy (cm)");
 441   gr2[6]->SetName("DCAXYMeanSPTTanTPCITS");
 442   gr2[6]->SetTitle("mean DCA_xy (TPC+ITS)");
 443   gr2[6]->GetHistogram()->Draw("colz");
 444
 445   gr2[6]->GetHistogram()->SetName("DCAXYMeanSPTTanTPCITS");
 446   aFolderObj->Add(gr2[6]->GetHistogram());
 447
 448   c1->cd(8);
 449   gr2[7] = AliMathBase::MakeStat2D(comp->fD1TanSPtTPCITS,4,2,4);
 450   gr2[7]->GetXaxis()->SetTitle("Tan(#theta)");
 451   gr2[7]->GetYaxis()->SetTitle("#sqrt{p_{t}(GeV)}");
 452   gr2[7]->GetZaxis()->SetTitle("mean DCA_z (cm)");
 453   gr2[7]->SetName("DCAZMeanSPTTanTPCITS");
 454   gr2[7]->SetTitle("mean DCA_z (TPC+ITS)");
 455   gr2[7]->GetHistogram()->Draw("colz");
 456
 457   gr2[7]->GetHistogram()->SetName("DCAZMeanSPTTanTPCITS");
 458   aFolderObj->Add(gr2[7]->GetHistogram());
 459
 460   // export objects to analysis folder
 461   fAnalysisFolder = ExportToFolder(aFolderObj);
 462
 463   // delete only TObjArray
 464   if(aFolderObj) delete aFolderObj;
 465 }
 466
 467 //_____________________________________________________________________________
 468 TFolder* AliComparisonDCA::ExportToFolder(TObjArray * array)
 469 {
 470   // recreate folder avery time and export objects to new one
 471   //
 472   AliComparisonDCA * comp=this;
 473   TFolder *folder = comp->GetAnalysisFolder();
 474
 475   TString name, title;
 476   TFolder *newFolder = 0;
 477   Int_t i = 0;
 478   Int_t size = array->GetSize();
 479
 480   if(folder) {
 481      // get name and title from old folder
 482      name = folder->GetName();
 483      title = folder->GetTitle();
 484
 485          // delete old one
 486      delete folder;
 487
 488          // create new one
 489      newFolder = CreateFolder(name.Data(),title.Data());
 490      newFolder->SetOwner();
 491
 492          // add objects to folder
 493      while(i < size) {
 494            newFolder->Add(array->At(i));
 495            i++;
 496          }
 497   }
 498
 499 return newFolder;
 500 }
 501
 502
 503 //_____________________________________________________________________________
 504 TFolder* AliComparisonDCA::CreateFolder(TString name,TString title) {
 505 // create folder for analysed histograms
 506 TFolder *folder = 0;
 507   folder = new TFolder(name.Data(),title.Data());
 508
 509   return folder;
 510 }