How to make a 2D (TH2I) histogram with non-equidistant binning

Newbie
1

Hi, I am using a TH2I histogram with defined bins to plot detector flood maps but I need to use the same with non-equidistant binning to add some extra inactive space between the detectors. How it can be done for the same. An example of my TH2I histogram is given below.

hFiredA[j] = new TH2I((nameF[j]+string(“Fired_Pixel”)).data(),(nameF[j]+string(“Fired Pixel A”)).data(),16,-25.6,25.6,16,-25.6,25.6);

ROOT Version: 6.22/08
Platform: Ubuntu

2

See:
https://root.cern/doc/master/classTH2I.html#aa991526756cc6a9f3b323d101a55bd95

And the constructor number 5 here:
https://root.cern/doc/master/classTH2.html#abee71174eeb77d309079b2be6d5fe02f

3

Thanks @couet
I am trying to make histogram like this

Int_t nbins = 35;
Float_t xbins[35], ybins[35];

hFiredA[j] = new TH2I((nameF[j]+string(“Fired_Pixel”)).data(),(nameF[j]+string(“Fired Pixel A”)).data(),nbins,xbins,nbins,ybins);

is this the correct form or not? I can assign xbins[35], and ybins[35] as per my bin starting points in the histogram, right?

Thank you for your time.

4

The doc says:

Constructor for Double_t variable bin size 2-D histograms.

Parameters:

[in] name name of histogram (avoid blanks)
[in] title histogram title. If title is of the form stringt;stringx;stringy;stringz the histogram title is set to stringt, the x axis title to stringx, the y axis title to stringy, etc.
[in] nbinsx number of bins
[in] xbins array of low-edges for each bin. This is an array of type double and size nbinsx+1
[in] nbinsy number of bins
[in] ybins array of low-edges for each bin. This is an array of type double and size nbinsy+1
5

Thank you for your suggestions. It works now.