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ratioplot1.C File Reference

Detailed Description

View in nbviewer Open in SWAN 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:412
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:634
1-D histogram with a double per channel (see TH1 documentation)}
Definition TH1.h:618
TAxis * GetXaxis()
Get the behaviour adopted by the object about the statoverflows. See EStatOverflows for more informat...
Definition TH1.h:320
virtual void FillRandom(const char *fname, Int_t ntimes=5000, TRandom *rng=nullptr)
Fill histogram following distribution in function fname.
Definition TH1.cxx:3525
TAxis * GetYaxis()
Definition TH1.h:321
virtual void Sumw2(Bool_t flag=kTRUE)
Create structure to store sum of squares of weights.
Definition TH1.cxx:8860
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.