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Reference Guide
ratioplot1.C File Reference

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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() {
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);
}
R__EXTERN TStyle * gStyle
Definition: TStyle.h:414
The Canvas class.
Definition: TCanvas.h:23
1-Dim function class
Definition: TF1.h:213
virtual void SetParameter(Int_t param, Double_t value)
Definition: TF1.h:639
1-D histogram with a double per channel (see TH1 documentation)}
Definition: TH1.h:620
TAxis * GetXaxis()
Definition: TH1.h:322
virtual void FillRandom(const char *fname, Int_t ntimes=5000, TRandom *rng=nullptr)
Fill histogram following distribution in function fname.
Definition: TH1.cxx:3513
TAxis * GetYaxis()
Definition: TH1.h:323
virtual void Sumw2(Bool_t flag=kTRUE)
Create structure to store sum of squares of weights.
Definition: TH1.cxx:8887
virtual void SetTitle(const char *title="")
Set the title of the TNamed.
Definition: TNamed.cxx:164
Class for displaying ratios, differences and fit residuals.
Definition: TRatioPlot.h:43
void SetOptStat(Int_t stat=1)
The type of information printed in the histogram statistics box can be selected via the parameter mod...
Definition: TStyle.cxx:1589
return c1
Definition: legend1.C:41
TH1F * h1
Definition: legend1.C:5
TF1 * f1
Definition: legend1.C:11
Author
Paul Gessinger

Definition in file ratioplot1.C.