Logo ROOT  
Reference Guide
 
Loading...
Searching...
No Matches
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:433
The Canvas class.
Definition TCanvas.h:23
void SetTitle(const char *title) override
Change/set the title.
Definition TH1.cxx:6686
void Draw(Option_t *option="") override
Draw this histogram with options.
Definition TH1.cxx:3066
void SetName(const char *name) override
Change the name of this histogram.
Definition TH1.cxx:8928
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:652
virtual Int_t AddBin(TObject *poly)
Adds a new bin to the histogram.
Definition TH2Poly.cxx:285
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:275
void SetPalette(Int_t ncolors=kBird, Int_t *colors=nullptr, Float_t alpha=1.)
See TColor::SetPalette.
Definition TStyle.cxx:1884
Author
Olivier Couet

Definition in file th2polyBoxes.C.