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cumulative.C File Reference

Detailed Description

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Illustrate use of the TH1::GetCumulative method.

#include <cassert>
#include <cmath>
#include "TH1.h"
#include "TH1D.h"
#include "TCanvas.h"
#include "TRandom.h"
TCanvas *cumulative()
TH1* h = new TH1D("h", "h", 100, -5., 5.);
h->FillRandom("gaus", 1u << 16);
// get the cumulative of h
TH1* hc = h->GetCumulative();
// check that c has the "right" contents
Double_t* integral = h->GetIntegral();
for (Int_t i = 1; i <= hc->GetNbinsX(); ++i) {
assert(std::abs(integral[i] * h->GetEntries() - hc->GetBinContent(i)) < 1e-7);
// draw histogram together with its cumulative distribution
TCanvas* c = new TCanvas;
return c;
#define c(i)
Definition RSha256.hxx:101
#define h(i)
Definition RSha256.hxx:106
#define e(i)
Definition RSha256.hxx:103
int Int_t
Definition RtypesCore.h:45
double Double_t
Definition RtypesCore.h:59
R__EXTERN TRandom * gRandom
Definition TRandom.h:62
The Canvas class.
Definition TCanvas.h:23
1-D histogram with a double per channel (see TH1 documentation)}
Definition TH1.h:621
TH1 is the base class of all histogram classes in ROOT.
Definition TH1.h:58
TH1 * GetCumulative(Bool_t forward=kTRUE, const char *suffix="_cumulative") const
Return a pointer to a histogram containing the cumulative content.
Definition TH1.cxx:2601
virtual Int_t GetNbinsX() const
Definition TH1.h:296
void Draw(Option_t *option="") override
Draw this histogram with options.
Definition TH1.cxx:3047
virtual Double_t * GetIntegral()
Return a pointer to the array of bins integral.
Definition TH1.cxx:2571
virtual Double_t GetBinContent(Int_t bin) const
Return content of bin number bin.
Definition TH1.cxx:5010
void Divide(Int_t nx=1, Int_t ny=1, Float_t xmargin=0.01, Float_t ymargin=0.01, Int_t color=0) override
Automatic pad generation by division.
Definition TPad.cxx:1153
virtual void SetSeed(ULong_t seed=0)
Set the random generator seed.
Definition TRandom.cxx:608
M. Schiller

Definition in file cumulative.C.