TRatioPlot (a few questions)

smd · June 22, 2021, 4:57pm

Hello,

I am trying to build a TRatioPlot. Its mostly successful. I have a THStack and some data. All displayed.

The issue is I want to add a title (something like "Preliminary Result ; Luminosity ; Channel "). I cant seem to figure out how to add this title to the plot. I have tried adding it to the upper plot but its not worked.

The other thing is I want to add in a checked histogram (or region between an upper and lower histogram) to represent some uncertainty on my backgrounds. I know of a number of ways to do this on an ordinary histogram, is there an easy way to add something like this to the TRatioPlot?

Thanks for any help

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couet · June 23, 2021, 6:46am

It should be no problem to add a TText or a TLatex on your plot. Can you post what you did already ?

It should be similar. Again can you provide an example ?

smd · June 23, 2021, 1:29pm

This is the snippet of code. All the plots labelled things like tau_plot_M_weighted are just TH1F’s.

I think the issue is that when the canvas appears the label is not visible. When I save it as say a PDF the label appears but its in completely the wrong place or the wrong size (since I can’t see it on the canvas when I’m interactive). I think this problem can be overcome with some trial and error. Currently I am using the Legend Header for the information.

The background histogram is the issue. Since its a THStack + a TH1F (the data). I can do something to make the upper limit (add a final histogram to the stack with the additonal + error bin content) but I’m not sure how to add in the lower limit since normally I would fill an area between two TH1F’s and this doesnt seem to be possible because adding a simple TH1F ontop of the THStack+TH1F plot isnt working. The data TH1F is added automatically because its involved with the ratio.

 TCanvas *c9 =  new TCanvas();
  tau_plot_M_weighted->SetFillColor(kBlue);
  tauD_plot_M_weighted->SetFillColor(kViolet-10);
  uds_plot_M->SetFillColor(kMagenta);
  cc_plot_M->SetFillColor(kOrange);
  mumu_plot_M->SetFillColor(kRed-7);
  b0b0_plot_M->SetFillColor(kGreen);
  bpbm_plot_M->SetFillColor(kGray);
  Background_M->SetFillStyle(3144);
  tau_plot_M_weighted->SetLineColor(kBlue);
  tauD_plot_M_weighted->SetLineColor(kViolet-10);
  uds_plot_M->SetLineColor(kMagenta);
  cc_plot_M->SetLineColor(kOrange);
  mumu_plot_M->SetLineColor(kRed-7);
  b0b0_plot_M->SetLineColor(kGreen);
  bpbm_plot_M->SetLineColor(kGray);
  Background_M->SetFillColor(kBlack);
  Background_M->SetLineColor(kBlack);
  c9->cd();
  THStack *Mh = new THStack("Mh ","Mh ");
  Mh->Add(mumu_plot_M);
  Mh->Add(b0b0_plot_M);
  Mh->Add(uds_plot_M);
  Mh->Add(bpbm_plot_M);
  Mh->Add(cc_plot_M);
  Mh->Add(tauD_plot_M_weighted);
  Mh->Add(tau_plot_M_weighted);
  Mh->Draw("histsame");
  auto rp9 = new TRatioPlot(Mh, data_plot_M);
  rp9->GetXaxis()->SetTitle("m_{h} [GeV]");
  rp9->Draw("same");
  rp9->GetLowerRefYaxis()->SetTitle("MC/Data");
  rp9->GetUpperRefXaxis()->SetTitle("m_{h}");
  rp9->GetUpperRefYaxis()->SetTitle("Entries");
  gPad->Modified();
  gPad->Update();
  TPad *p9 = rp9->GetUpperPad();
  auto leg9 = p9->BuildLegend(0.1,0.7,0.48,0.9, "","f");
  rp9->GetUpperPad();
  /*auto *th3 = new TText(0.9,0.823,"Preliminary");
  th3->SetTextAlign(31); th3->SetTextSize(0.5);
  th3->Draw();*/
  leg9->SetHeader(LegendTitle,"L");
  leg9->AddEntry(data_plot_M,"data","pl");
  p9->Modified(); 
  p9->Update();
  c9->Draw();

couet · June 23, 2021, 2:04pm

Can you post something we can run ?

smd · June 23, 2021, 2:22pm

Sure, here is a simple example to replicate the issues:

void MakeRatio(){
  TString LegendTitle = "Preliminary";
  TH1F *uds_plot_M = new TH1F("uds M", "uds", 50,  0.2,1);
  TH1F *Background_M = new TH1F("Backg. Unc.", "Backg. Unc.", 50,  0.2,1);
  TH1F *tau_plot_M_weighted  = new TH1F("#tau M", "#tau signal", 50,  0.2,1);
  TH1F *tauD_plot_M_weighted  = new TH1F("#tau M", "#tau non-signal", 50,  0.2,1);
  TH1F *data_plot_M = new TH1F("data", "data", 50, 0.2,1);

  uds_plot_M->FillRandom("gaus",200);
  tau_plot_M_weighted->FillRandom("gaus",2000);
  tauD_plot_M_weighted->FillRandom("gaus",500);
  data_plot_M->FillRandom("gaus",3000);
  for(int bin=0; bin<data_plot_M->GetNbinsX(); bin++){
    double content = data_plot_M->GetBinContent(bin);
    double newcontent = (0.1)*content;
    Background_M->SetBinContent (bin, newcontent);
    data_plot_M->SetBinError(bin,0.1*content+sqrt(content));
  }


  TCanvas *c9 =  new TCanvas();
  tau_plot_M_weighted->SetFillColor(kBlue);
  tauD_plot_M_weighted->SetFillColor(kViolet-10);
  uds_plot_M->SetFillColor(kMagenta);
  Background_M->SetFillStyle(3144);
  tau_plot_M_weighted->SetLineColor(kBlue);
  tauD_plot_M_weighted->SetLineColor(kViolet-10);
  uds_plot_M->SetLineColor(kMagenta);
  Background_M->SetFillColor(kBlack);
  Background_M->SetLineColor(kBlack);

  c9->cd();
  THStack *Mh = new THStack("Mh ","Mh ");
  Mh->Add(uds_plot_M);
  Mh->Add(tauD_plot_M_weighted);
  Mh->Add(tau_plot_M_weighted);
  //Mh->Add(Background_M); Option 1 (works but no lower limit)
  Mh->Draw("hist");
  auto rp9 = new TRatioPlot(Mh, data_plot_M);
  rp9->GetXaxis()->SetTitle("m_{h} [GeV]");
  rp9->Draw("same");
  rp9->GetLowerRefYaxis()->SetTitle("MC/Data");
  rp9->GetUpperRefXaxis()->SetTitle("m_{h}");
  rp9->GetUpperRefYaxis()->SetTitle("Entries");
  gPad->Modified();
  gPad->Update();
  TPad *p9 = rp9->GetUpperPad();
  Background_M->Draw("histsame"); //Option2 (doesnt work) - would need to change bin content to make this work for real obviously!
  auto leg9 = p9->BuildLegend(0.1,0.7,0.48,0.9, "","f");
  rp9->GetUpperPad();
  auto *th3 = new TText(0.9,0.823,"Preliminary");// TODO: This doesnt show up opn top pad
  th3->SetTextAlign(31); th3->SetTextSize(0.5);
  th3->Draw();
  leg9->SetHeader(LegendTitle,"L");
  leg9->AddEntry(data_plot_M,"data","pl");
  p9->Modified();
  p9->Update();
  c9->Draw();
}

You can see for the background issue I tried 2 options. Option 1 gives me that upper limit but no way of getting the lower. Option 2 is preferable and would lead to me adding a second for the lower limit, nothing is added to the canvas when Option 2 is used. I also have the added Text option to show how that issue is occurring.

couet · June 23, 2021, 2:41pm

Let’s start form a cleaned-up macro:

void MakeRatio(){
   TH1F *uds_plot_M = new TH1F("uds M", "uds", 50,  0.2,1);
   TH1F *Background_M = new TH1F("Backg. Unc.", "Backg. Unc.", 50,  0.2,1);
   TH1F *tau_plot_M_weighted  = new TH1F("#tau M", "#tau signal", 50,  0.2,1);
   TH1F *tauD_plot_M_weighted  = new TH1F("#tau M", "#tau non-signal", 50,  0.2,1);
   TH1F *data_plot_M = new TH1F("data", "data", 50, 0.2,1);

   uds_plot_M->FillRandom("gaus",200);
   tau_plot_M_weighted->FillRandom("gaus",2000);
   tauD_plot_M_weighted->FillRandom("gaus",500);
   data_plot_M->FillRandom("gaus",3000);

   for (int bin=0; bin<data_plot_M->GetNbinsX(); bin++) {
      double content = data_plot_M->GetBinContent(bin);
      double newcontent = (0.1)*content;
      Background_M->SetBinContent (bin, newcontent);
      data_plot_M->SetBinError(bin,0.1*content+sqrt(content));
   }

   TCanvas *c9 =  new TCanvas();
   tau_plot_M_weighted->SetFillColor(kBlue);
   tauD_plot_M_weighted->SetFillColor(kViolet-10);
   uds_plot_M->SetFillColor(kMagenta);
   Background_M->SetFillStyle(3144);
   tau_plot_M_weighted->SetLineColor(kBlue);
   tauD_plot_M_weighted->SetLineColor(kViolet-10);
   uds_plot_M->SetLineColor(kMagenta);
   Background_M->SetFillColor(kBlack);
   Background_M->SetLineColor(kBlack);

   THStack *Mh = new THStack("Mh ","Mh ");
   Mh->Add(uds_plot_M);
   Mh->Add(tauD_plot_M_weighted);
   Mh->Add(tau_plot_M_weighted);

   auto rp9 = new TRatioPlot(Mh, data_plot_M);
   rp9->Draw();

   rp9->GetLowerRefYaxis()->SetTitle("MC/Data");
   rp9->GetUpperRefXaxis()->SetTitle("m_{h}");
   rp9->GetUpperRefYaxis()->SetTitle("Entries");

   auto leg9 = rp9->GetUpperPad()->BuildLegend(0.1,0.7,0.48,0.9, "","f");
   leg9->SetHeader("Preliminary","L");
   leg9->AddEntry(data_plot_M,"data","pl");

   rp9->GetUpperPad()->cd();
   auto *th3 = new TText(0.9,0.823,"Preliminary");// TODO: This doesnt show up opn top pad
   th3->SetTextAlign(31); th3->SetTextSize(0.3);
   th3->Draw();
}

It gives:

Let me know if it is not ok yet.

smd · June 23, 2021, 2:53pm

Thanks , yes this works, it gives the label as you show there which I can now resize and move on my real plot. I still dont see any extra histograms, I guess thats the next step

couet · June 23, 2021, 3:03pm

Let me know what you want to see as extra…

system · July 7, 2021, 3:04pm

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