Rebin to variable-size bins, keeping the same area?

ROOT
1

Hi,

I have a histogram of pT spectrum. I want to rebin it using variable-size bins

TH1F* h = new TH1F("h", "h", 100, 0, 500); Double_t xbins[14] = {160,170,180,190,200,220,240,260,280,300,340,380,420,500}; TH1F* h1 = (TH1F*) h->Rebin(13, "h1", xbins);

But what happens is, the bins of larger width will have larger areas. How can I rebin them so that, when I group 2 bins together, the content of the new bin is the sum of both bins divided by 2?

Thanks much,
Jia Fu

2

Hi,

You might want to scale the histogram with the bin width (i.e dividing each content by its bin width). You can do this by calling

h1->Scale(1,"width");

Lorenzo

3

Thanks Lorenzo, that’s exactly what I’m looking for.