I observe a strange behaviour when dividing 2D histograms (TH2D).
I first fill a few TH2Ds with ~10^5 entries, I divide two of them and then I plot some projection with errors. I always get by few orders of magnitude too high errors.
I tried histo->Sumw2() at many places (after creation. before filling, before dividing), but with no effect. I use version 3.10/02 .
Also Scaling behaves weirdly - if I histo2d->Scale(X), relative errors reduce by sqrt(X) - i guess they should not change while scaling…
with best regards and wishing good time developing
Please send the shortest possible running script reproducing this problem.
this is the shortest way I can do:
TH2D h2=new TH2D(“h2”,“test”,11,-5,5,11,-5,5)
TF2 f2 = new TF2(“f2”,"sin(xx+yy)/(xx+yy)")
here one observes that the errors are way too large
and here the relative errors change
with the best regards
Replace the line
You should get the following picture: