Logo ROOT  
Reference Guide
th2polyBoxes.C File Reference

Detailed Description

View in nbviewer Open in SWAN This tutorial illustrates how to create an histogram with polygonal bins (TH2Poly).

The bins are boxes.

TCanvas *th2polyBoxes() {
TCanvas *ch2p2 = new TCanvas("ch2p2","ch2p2",600,400);
TH2Poly *h2p = new TH2Poly();
h2p->SetName("Boxes");
h2p->SetTitle("Boxes");
Int_t i,j;
Int_t nx = 40;
Int_t ny = 40;
Double_t xval1,yval1,xval2,yval2;
Double_t dx=0.2, dy=0.1;
xval1 = 0.;
xval2 = dx;
for (i = 0; i<nx; i++) {
yval1 = 0.;
yval2 = dy;
for (j = 0; j<ny; j++) {
h2p->AddBin(xval1, yval1, xval2, yval2);
yval1 = yval2;
yval2 = yval2+yval2*dy;
}
xval1 = xval2;
xval2 = xval2+xval2*dx;
}
TRandom ran;
for (i = 0; i<300000; i++) {
h2p->Fill(50*ran.Gaus(2.,1), ran.Gaus(2.,1));
}
h2p->Draw("COLZ");
return ch2p2;
}
int Int_t
Definition: RtypesCore.h:45
double Double_t
Definition: RtypesCore.h:59
R__EXTERN TStyle * gStyle
Definition: TStyle.h:414
The Canvas class.
Definition: TCanvas.h:23
void SetTitle(const char *title) override
See GetStatOverflows for more information.
Definition: TH1.cxx:6708
void Draw(Option_t *option="") override
Draw this histogram with options.
Definition: TH1.cxx:3070
void SetName(const char *name) override
Change the name of this histogram.
Definition: TH1.cxx:8835
2D Histogram with Polygonal Bins
Definition: TH2Poly.h:66
Int_t Fill(Double_t x, Double_t y) override
Increment the bin containing (x,y) by 1.
Definition: TH2Poly.cxx:589
virtual Int_t AddBin(TObject *poly)
Adds a new bin to the histogram.
Definition: TH2Poly.cxx:222
This is the base class for the ROOT Random number generators.
Definition: TRandom.h:27
virtual Double_t Gaus(Double_t mean=0, Double_t sigma=1)
Samples a random number from the standard Normal (Gaussian) Distribution with the given mean and sigm...
Definition: TRandom.cxx:274
void SetPalette(Int_t ncolors=kBird, Int_t *colors=0, Float_t alpha=1.)
See TColor::SetPalette.
Definition: TStyle.cxx:1783
Author
Olivier Couet

Definition in file th2polyBoxes.C.