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Reference Guide
ratioplot1.C
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1/// \file
2/// \ingroup tutorial_hist
3/// \notebook
4/// Example creating a simple ratio plot of two histograms using the `pois` division option.
5/// Two histograms are set up and filled with random numbers. The constructor of `TRatioPlot`
6/// takes the to histograms, name and title for the object, drawing options for the histograms (`hist` and `E` in this case)
7/// and a drawing option for the output graph.
8///
9/// \macro_image
10/// \macro_code
11///
12/// \author Paul Gessinger
13
14void ratioplot1() {
16 auto c1 = new TCanvas("c1", "A ratio example");
17 auto h1 = new TH1D("h1", "h1", 50, 0, 10);
18 auto h2 = new TH1D("h2", "h2", 50, 0, 10);
19 auto f1 = new TF1("f1", "exp(- x/[0] )");
20 f1->SetParameter(0, 3);
21 h1->FillRandom("f1", 1900);
22 h2->FillRandom("f1", 2000);
23 h1->Sumw2();
24 h2->Scale(1.9 / 2.);
25 h1->GetXaxis()->SetTitle("x");
26 h1->GetYaxis()->SetTitle("y");
27 auto rp = new TRatioPlot(h1, h2);
28 c1->SetTicks(0, 1);
29 rp->Draw();
30 rp->GetLowYaxis()->SetNdivisions(505);
31}
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