Rebinning data in a multigraph

ROOT
1

Hello,

I wrote a macro to fit some peaks

The macro fits the ranges of the plot by a function, then I defined a totalFit function that is the sum of the functions used in each subrange.

@yus helped me to solve a bug here (Problems defining a multifit - #9 by faca87)

Here an example (maybe I’ve to improve the initial parameter, but for the moment it’s ok this plot)

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I’ve one more question.

As you can see in the following figure,

Screenshot 2024-06-14 183646
Screenshot 2024-06-14 1836461337×730 218 KB

they plotted the full spectrum that is the sum of S1+S2+S3+ S4+S5+S6 (small plots). To plot the full spectrum they rebinned in 28 days (as it is written in the caption).

I tried to rebin in this way:

int bindays=28;
int nbins = static_cast((x2 - x1) / bindays);

…

mg->GetXaxis()->SetNdivisions(nbins);

But I don’t see a decreasing in the number of points as in the figure of the article

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multiflares.cpp (8.1 KB)

2

Hi again,

a TGraph (or TMultiGraph in your case) has no concept of “bins”. Only histograms do. A TAttAxis::SetNdivisions() has nothing to do with bins, it’s really about ticks. I suggest you either rework your text files or try using TGraph::GetHistogram() and rebin that.

3

Thank you @yus.
If I create a histogram using gethistogram, how to keep the correspondence on the y-axis? (i.e. do not alternate the flux values)?

4

Sorry, the TGraph::GetHistogram() won’t work here. It is always empty as explained at TGraph GetHistogram() - #2 by couet. You should try to create a histogram from your multigraph yourself.