ratioplot1.C File Reference

Detailed Description

Example creating a simple ratio plot of two histograms using the pois division option.

Two histograms are set up and filled with random numbers. The constructor of TRatioPlot takes the to histograms, name and title for the object, drawing options for the histograms (hist and E in this case) and a drawing option for the output graph.

void ratioplot1() {
   gStyle->SetOptStat(0);
   auto c1 = new TCanvas("c1", "A ratio example");
   auto h1 = new TH1D("h1", "h1", 50, 0, 10);
   auto h2 = new TH1D("h2", "h2", 50, 0, 10);
   auto f1 = new TF1("f1", "exp(- x/[0] )");
   f1->SetParameter(0, 3);
   h1->FillRandom("f1", 1900);
   h2->FillRandom("f1", 2000);
   h1->Sumw2();
   h2->Scale(1.9 / 2.);
   h1->GetXaxis()->SetTitle("x");
   h1->GetYaxis()->SetTitle("y");
   auto rp = new TRatioPlot(h1, h2);
   c1->SetTicks(0, 1);
   rp->Draw();
   rp->GetLowYaxis()->SetNdivisions(505);
   c1->Update();
}

Author

Paul Gessinger

Definition in file ratioplot1.C.