#include "TH1.h"
#include "TCanvas.h"

#include "TRandom3.h"

int plot_rebin_divide()
{
   TRandom3 rand(47);

   TH1F * numer = new TH1F("numer", "numer", 40, 0., 200.);
   for ( int j = 0; j < 200; ++j )
      numer->Fill(rand.Gaus(80,30));

   TH1F * denom = new TH1F("denom", "denom", 40, 0., 200.);
   for ( int j = 0; j < 1400; ++j )
      denom->Fill(rand.Gaus(80,170));
   
   TCanvas *can = new TCanvas("can", "", 700, 500);
   can->Divide(2,2);
   can->cd(1);
   numer->Draw();
   can->cd(2);
   denom->Draw();

   int nbins = 6;
   double bins[] = {0.0, 40.0, 80.0, 90.0, 150.0, 200.0};

   numer = (TH1F*) numer->Rebin(nbins-1, "%s_rebin_number", bins);
   can->cd(3);
   numer->Draw();

   denom = (TH1F*) denom->Rebin(nbins-1, "%s_rebin_denom", bins);
   can->cd(4);
   denom->Draw();

   TH1F * ratioFails = new TH1F("ratioFails", "ratioFails", 
                           numer->GetXaxis()->GetNbins(), 
                           numer->GetXaxis()->GetXmin(), 
                           numer->GetXaxis()->GetXmax() );
   ratioFails->SetMarkerStyle(8);
   ratioFails->Divide(numer, denom, 1.0, 1.0);


   TCanvas* c2 = new TCanvas("can2", "", 700, 500);
   c2->Divide(1,2);
   c2->cd(1);
   ratioFails->Draw();

   TH1F* ratioWorks = (TH1F*) numer->Clone();
   ratioWorks->SetMarkerStyle(8);
   ratioWorks->Divide(denom);
   c2->cd(2);
   ratioWorks->Draw();


   return 0;
}