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Reference Guide
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);
}
Author
Paul Gessinger

Definition in file ratioplot1.C.

TH1D
1-D histogram with a double per channel (see TH1 documentation)}
Definition: TH1.h:615
h1
TH1F * h1
Definition: legend1.C:5
TF1::SetParameter
virtual void SetParameter(Int_t param, Double_t value)
Definition: TF1.h:630
gStyle
R__EXTERN TStyle * gStyle
Definition: TStyle.h:412
TH1::GetYaxis
TAxis * GetYaxis()
Definition: TH1.h:318
TH2::FillRandom
virtual void FillRandom(const char *fname, Int_t ntimes=5000)
Fill histogram following distribution in function fname.
Definition: TH2.cxx:599
ratioplot1
Definition: ratioplot1.py:1
TNamed::SetTitle
virtual void SetTitle(const char *title="")
Set the title of the TNamed.
Definition: TNamed.cxx:164
TH1::FillRandom
virtual void FillRandom(const char *fname, Int_t ntimes=5000)
Fill histogram following distribution in function fname.
Definition: TH1.cxx:3444
TStyle::SetOptStat
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:1592
f1
TF1 * f1
Definition: legend1.C:11
TCanvas
Definition: TCanvas.h:23
TRatioPlot
Definition: TRatioPlot.h:43
TH1::Sumw2
virtual void Sumw2(Bool_t flag=kTRUE)
Create structure to store sum of squares of weights.
Definition: TH1.cxx:8475
TF1
1-Dim function class
Definition: TF1.h:212
TH1::GetXaxis
TAxis * GetXaxis()
Get the behaviour adopted by the object about the statoverflows. See EStatOverflows for more informat...
Definition: TH1.h:317
TH1::Scale
virtual void Scale(Double_t c1=1, Option_t *option="")
Multiply this histogram by a constant c1.
Definition: TH1.cxx:6245
c1
return c1
Definition: legend1.C:41