void plot_pid_purity(){
  gStyle->SetOptStat(0);
  TCanvas *c1=new TCanvas("c1","c1",1600,600);
  c1->Divide(2,2);
  
  TH2F *MyKmDenom=(TH2F *)(_file0->FindObjectAny("KmDenom"))->Clone("KmDenom");
  TH2F *MyKmNumer_Em=(TH2F *)(_file0->FindObjectAny("KmNumer_Em"))->Clone("MyKmNumer_Em");
  TH2F *MyKmNumer_Pim=(TH2F *)(_file0->FindObjectAny("KmNumer_Pim"))->Clone("MyKmNumer_Pim");
  TH2F *MyKmNumer_Km=(TH2F *)(_file0->FindObjectAny("KmNumer_Km"))->Clone("MyKmNumer_Km");
  TH2F *MyKmNumer_aP=(TH2F *)(_file0->FindObjectAny("KmNumer_aP"))->Clone("MyKmNumer_aP");

  MyKmDenom->Sumw2();
  MyKmNumer_Em->Sumw2(); 
  MyKmNumer_Pim->Sumw2();
  MyKmNumer_Km->Sumw2();
  MyKmNumer_aP->Sumw2();

  MyKmNumer_Em->Divide(MyKmDenom);
  MyKmNumer_Pim->Divide(MyKmDenom);
  MyKmNumer_Km->Divide(MyKmDenom);
  MyKmNumer_aP->Divide(MyKmDenom);

  c1->cd(1);

  MyKmNumer_Em->GetXaxis()->SetRangeUser(0,40);
  MyKmNumer_Em->GetXaxis()->SetLabelSize(0.04); 
  MyKmNumer_Em->GetXaxis()->SetTitleSize(0.05); 
  MyKmNumer_Em->GetYaxis()->SetLabelSize(0.04); 
  MyKmNumer_Em->GetYaxis()->SetTitleSize(0.05); 
  MyKmNumer_Em->GetXaxis()->SetRangeUser(0,20);  
  MyKmNumer_Em->SetTitle("Ratio of e^{-} ID to true K^{-}");
  MyKmNumer_Em->SetXTitle("#theta [degrees]");
  MyKmNumer_Em->SetYTitle("p [GeV/c]");
  MyKmNumer_Em->Draw("colz");

  c1->cd(2);

  MyKmNumer_Pim->GetXaxis()->SetLabelSize(0.04); 
  MyKmNumer_Pim->GetXaxis()->SetTitleSize(0.05); 
  MyKmNumer_Pim->GetYaxis()->SetLabelSize(0.04); 
  MyKmNumer_Pim->GetYaxis()->SetTitleSize(0.05);  
  MyKmNumer_Pim->GetXaxis()->SetRangeUser(0,20); 
  MyKmNumer_Pim->SetTitle("Ratio of #pi^{-} ID to true K^{-}");
  MyKmNumer_Pim->SetXTitle("#theta [degrees]");
  MyKmNumer_Pim->SetYTitle("p [GeV/c]");
  MyKmNumer_Pim->Draw("colz");

  c1->cd(3);

  MyKmNumer_Km->GetXaxis()->SetRangeUser(0,20);
  MyKmNumer_Km->GetXaxis()->SetLabelSize(0.04); 
  MyKmNumer_Km->GetXaxis()->SetTitleSize(0.05); 
  MyKmNumer_Km->GetYaxis()->SetLabelSize(0.04); 
  MyKmNumer_Km->GetYaxis()->SetTitleSize(0.05);  
  MyKmNumer_Km->SetTitle("Ratio of K^{-} ID to true K^{-}");
  MyKmNumer_Km->SetXTitle("#theta [degrees]");
  MyKmNumer_Km->SetYTitle("p [GeV/c]");
  MyKmNumer_Km->Draw("colz");

  c1->cd(4);  
  MyKmNumer_aP->GetXaxis()->SetRangeUser(0,20);
  MyKmNumer_aP->GetXaxis()->SetLabelSize(0.04); 
  MyKmNumer_aP->GetXaxis()->SetTitleSize(0.05); 
  MyKmNumer_aP->GetYaxis()->SetLabelSize(0.04); 
  MyKmNumer_aP->GetYaxis()->SetTitleSize(0.05);  
  MyKmNumer_aP->SetTitle("Ratio of anti-proton ID to true K^{-}");
  MyKmNumer_aP->SetXTitle("#theta [degrees]");
  MyKmNumer_aP->SetYTitle("p [GeV/c]");
  MyKmNumer_aP->Draw("colz");


  TCanvas *c2=new TCanvas();
  
  TH1D *km=MyKmNumer_Km->ProjectionX("km",21,21);
  TH1D *ap=MyKmNumer_aP->ProjectionX("ap",21,21);  
  TH1D *pm=MyKmNumer_Pim->ProjectionX("pm",21,21);
  TH1D *em=MyKmNumer_Em->ProjectionX("em",21,21);
  
  km->GetXaxis()->SetTitleOffset(0.8);
  km->GetYaxis()->SetRangeUser(0,1.);
  km->SetTitle("Kaon PID efficiency at p=2.0 GeV/c");
  km->SetYTitle("fraction PIDFOM ID/true ID");
  km->SetMarkerColor(1);
  km->SetLineColor(1);
  km->SetMarkerStyle(20);
  km->Draw();
  em->SetMarkerColor(2);
  em->SetLineColor(2);
  em->SetMarkerStyle(21);
  em->Draw("same"); 
  pm->SetMarkerColor(4);
  pm->SetLineColor(4);
  pm->SetMarkerStyle(22);
  pm->Draw("same");
  ap->SetMarkerColor(8);
  ap->SetLineColor(8);
  ap->SetMarkerStyle(23);
  ap->Draw("same");
  
  
  TCanvas *c3=new TCanvas();
  
  TH1D *km2=MyKmNumer_Km->ProjectionX("km2",41,41);
  TH1D *ap2=MyKmNumer_aP->ProjectionX("ap2",41,41);  
  TH1D *pm2=MyKmNumer_Pim->ProjectionX("pm2",41,41);
  TH1D *em2=MyKmNumer_Em->ProjectionX("em2",41,41);

  km2->GetXaxis()->SetTitleOffset(0.8);
  km2->GetYaxis()->SetRangeUser(0,1.);
  km2->SetTitle("Kaon PID efficiency at p=4.0 GeV/c");
  km2->SetYTitle("fraction PIDFOM ID/true ID");
  km2->SetMarkerColor(1);
  km2->SetLineColor(1);
  km2->SetMarkerStyle(20);
  km2->Draw();
  em2->SetMarkerColor(2);
  em2->SetLineColor(2);
  em2->SetMarkerStyle(21);
  em2->Draw("same"); 
  pm2->SetMarkerColor(4);
  pm2->SetLineColor(4);
  pm2->SetMarkerStyle(22);
  pm2->Draw("same");
  ap2->SetMarkerColor(8);
  ap2->SetLineColor(8);
  ap2->SetMarkerStyle(23);
  ap2->Draw("same");
  


}