void Compare_DPM_FTF_MC(){
  gStyle->SetOptStat(0);
  gStyle->SetLabelSize(0.045,"xyz");
  gStyle->SetTitleYSize(0.04);
  gStyle->SetTitleXSize(0.04);
  TString resname= "DPM_vs_FTF";
  TString resname_pdf = resname+".pdf";
  TString resname_pdf_o = resname_pdf+"(";
  TString resname_pdf_c = resname_pdf+")";
  Long64_t nentries = 2e7;
  //Long64_t nentries = 2e3;
// virtual Long64_t	Project(const char* hname, const char* varexp, const char* selection = "", Option_t* option = "", Long64_t nentries = 1000000000, Long64_t firstentry = 0)
 double th_lim=150;
 TString cond = "Particles.Theta()<0.150 && Npart>0";
  // double th_lim=TMath::Pi();
  // TString cond = "Particles.Theta()<2*TMath::Pi()";
  TFile * finDPM = new TFile("DPM_inel_15GeV.root","READ");
  TTree *treeDPM = (TTree *)finDPM->Get("data");
  TH1 *nmultDPM = new TH1I("nmultDPM",";trks/ev",20,0,20);
  treeDPM->Project("nmultDPM","Npart","","",nentries);
  TH1 *thMCdpm = new TH1D("thMCdpm",";#theta_{MC}, rad",3e3,0,th_lim);
  int nDPM = treeDPM->Project("thMCdpm","1e3*Particles.Theta()",cond.Data(),"",nentries);
  cout<<"nDPM = "<<nDPM<<endl;
  TH1 *phMCdpm = new TH1D("phMCdpm",";#phi_{MC}, rad",3e3,0,2*TMath::Pi());
  treeDPM->Project("phMCdpm","Particles.Phi()",cond.Data(),"",nentries);
  TH1 *momMCdpm = new TH1D("momMCdpm","; Pz_{MC}, GeV/c",3e3,0,20);
  int ndpm = treeDPM->Project("momMCdpm","Particles.fPz",cond.Data(),"",nentries);// mom in GeV
  TFile * finFTF = new TFile("FTF_inel_15GeV_2.root","READ");
  TTree *treeFTF = (TTree *)finFTF->Get("data");
  TH1 *nmultFTF = new TH1I("nmultFTF",";trks/ev",20,0,20);
  treeFTF->Project("nmultFTF","Npart","","",nentries);
  TH1 *thMCftf = new TH1D("thMCftf",";#theta_{MC}, rad",3e3,0,th_lim);
  int nFTF = treeFTF->Project("thMCftf","1e3*Particles.Theta()",cond.Data(),"",nentries);
  cout<<"nFTF = "<<nFTF<<endl;
  TH1 *phMCftf = new TH1D("phMCftf",";#phi_{MC}, rad",3e3,0,2*TMath::Pi());
  treeFTF->Project("phMCftf","Particles.Phi()",cond.Data(),"",nentries);
  TH1 *momMCftf = new TH1D("momMCftf","; Pz_{MC}, GeV/c",3e3,0,20);
  treeFTF->Project("momMCftf","Particles.fPz",cond.Data(),"",nentries);// mom in MeV source of long time???
 // TFile * finFTF = new TFile("FTF_inel_15GeV.root","READ");
 // TTree *treeFTF = (TTree *)finFTF->Get("data");
  TLegend *leg = new TLegend(0.81,0.85,0.93,0.95);
  leg->SetFillColor(0);
  leg->SetName("leg");
  TCanvas c1;
  //c1.SetLogy();
  nmultDPM->SetLineColor(1);
  nmultDPM->SetLineWidth(2.5);
  nmultFTF->SetLineColor(2);
  nmultFTF->SetLineWidth(2.5);
  nmultFTF->Draw();
  nmultDPM->Draw("same");
  leg->AddEntry(nmultFTF,"FTF","l");
  leg->AddEntry(nmultDPM,"DPM","l");
  leg->Draw();
  c1.Print(resname_pdf_o);
  c1.Clear();
  TH1D *nmultnorm = (TH1D*)nmultDPM->Clone("nmultnorm");
  TH1D *nmultnue = (TH1D*)nmultFTF->Clone("nmultnue");
  nmultnue->Add(nmultnorm,-1);
  nmultnue->Divide(nmultnue,nmultnorm,100,1);
  nmultnue->GetYaxis()->SetTitle("(FTF-DPM)/DPM, %");
  // nmultnue->SetMaximum(50.);
  // nmultnue->SetMinimum(-50.);
  nmultnue->Draw();
  c1.Print(resname_pdf_o);
  c1.Clear();

  thMCdpm->SetLineColor(1);
  thMCdpm->SetLineWidth(2.5);
  thMCftf->SetLineColor(2);
  thMCftf->SetLineWidth(2.5);
  thMCdpm->SetMinimum(0);
  //  thMCftf->SetMaximum(2e4);
  thMCdpm->Draw();
  thMCftf->Draw("same");
  leg->Draw();
  c1.Print(resname_pdf_o);
  c1.Clear();
  TH1D *thMCnorm = (TH1D*)thMCdpm->Clone("thMCnorm");
  TH1D *thMCnue = (TH1D*)thMCftf->Clone("thMCnue");
  thMCnue->Add(thMCnorm,-1);
  thMCnue->Divide(thMCnue,thMCnorm,100,1);
  thMCnue->GetYaxis()->SetTitle("(FTF-DPM)/DPM, %");
  thMCnue->Draw();
  // thMCnue->SetMinimum(-50);
  // thMCnue->SetMaximum(50);
  c1.Print(resname_pdf_o);
  c1.Clear();

  phMCdpm->SetLineColor(1);
  phMCdpm->SetLineWidth(2.5);
  phMCftf->SetLineColor(2);
  phMCftf->SetLineWidth(2.5);
  phMCdpm->SetMinimum(0);
  phMCdpm->Draw();
  phMCftf->Draw("same");
  leg->Draw();
  c1.Print(resname_pdf_o);
  c1.Clear();
  TH1D *phMCnorm = (TH1D*)phMCdpm->Clone("phMCnorm");
  TH1D *phMCnue = (TH1D*)phMCftf->Clone("phMCnue");
  phMCnue->Add(phMCnorm,-1);
  phMCnue->Divide(phMCnue,phMCnorm,100,1);
  phMCnue->GetYaxis()->SetTitle("(FTF-DPM)/DPM, %");
  phMCnue->Draw();
  phMCnue->SetMinimum(-10);
  phMCnue->SetMaximum(10);
  c1.Print(resname_pdf_o);
  c1.Clear();

  momMCdpm->SetLineColor(1);
  momMCdpm->SetLineWidth(2.5);
  momMCftf->SetLineColor(2);
  momMCftf->SetLineWidth(2.5);
  momMCdpm->SetMinimum(0);
  momMCdpm->Draw();
  momMCftf->Draw("same");
  leg->Draw();
  c1.Print(resname_pdf_o);
  c1.Clear();
  TH1D *momMCnorm = (TH1D*)momMCdpm->Clone("momMCnorm");
  TH1D *momMCnue = (TH1D*)momMCftf->Clone("momMCnue");
  momMCnue->Add(momMCnorm,-1);
  momMCnue->Divide(momMCnue,momMCnorm,100,1);
  momMCnue->GetYaxis()->SetTitle("(FTF-DPM)/DPM, %");
  momMCnue->Draw();
  momMCnue->SetMinimum(-100);
  momMCnue->SetMaximum(500);
  c1.Print(resname_pdf_c);
  
  TString out = resname+".root";
  TFile *f = new TFile(out,"RECREATE");
  momMCnue->Write();
  momMCdpm->Write();
  momMCftf->Write();
  phMCnue->Write();
  phMCdpm->Write();
  phMCftf->Write();
  thMCnue->Write();
  thMCdpm->Write();
  thMCftf->Write();
  nmultnue->Write();
  nmultDPM->Write();
  nmultFTF->Write();
  leg->Write();
  f->Write();
  f->Close();
}