Rebin a TProfile into a new TProfile with a variable-width bins

[Liuyao_Zhang]

Hello,

I tried to rebin one TProfile into a new TProfile with a variable bin width;
I almost followed the root document from

case 2 xbins!=0

Double_t xbins[25] = {...}; 
hp->Rebin(24,"hpnew",xbins);

But, looks like the strategy doesn’t work;

Here, I pasted my minimal code:

void RebinTProfile() {
    int nbins = 8;
    double xlow = 0.0;
    double xhigh = 8.0;
    TProfile *profile = new TProfile("profile", "Example TProfile", nbins, xlow, xhigh);

    // Fill the TProfile with some data
    TRandom rand;
    for (int i = 0; i < 10000; ++i) {
        double x = rand.Uniform(xlow, xhigh);
        double y = x * x + rand.Gaus(0, 1);  // Example: y = x^2 + random Gaussian noise
        profile->Fill(x, y);
    }

    Double_t xbins[3] = {0.0, 3.0, 8.0};
    TProfile *rebinnedProfile = (TProfile* )profile->Clone("rebinnedProfile");
    rebinnedProfile->Rebin(2, "rebinnedProfile ", xbins);

    // Optionally, plot the original and rebinned TProfile histograms
    TCanvas *canvas = new TCanvas("canvas", "TProfile Example", 800, 600);
    canvas->Divide(1, 2);

    canvas->cd(1);
    profile->Draw();

    canvas->cd(2);
    rebinnedProfile->Draw();

}  

Thanks in advance.

Best
Liuyao

[Danilo]

Hi Liuyao,

Thanks for the reproducer. I see an odd behaviour too: let me come back to you about this

Cheers,
Danilo

[Liuyao_Zhang]

Dear @Danilo,
do you have any updates?

Best
Liuyao