Please read tips for efficient and successful posting and posting code Please fill also the fields below. Note that root -b -q will tell you this info, and starting from 6.28/06 upwards, you can call .forum bug from the ROOT prompt to pre-populate a topic. ROOT Version: 6.28.10 Platform: ubuntu …

For ROOT versions > 6.28.10 I encountered an issue/bug when plotting a TF1 in a smaller x-range than the x-ranges where it is defined. The attached small code and 2 plots show the issue for the simple exponential function. The function is defined in three x-ranges (from x=0 to xmax = 10, 20 and 30).…

Thanks for the suggestion, but why it is only needed for the ROOT versions >6.28.10 ?

I don’t know, maybe a ROOT developer or someone familiar with the change can tell. The code for SetNpx hasn’t changed in many versions (you can choose other versions in a dropdown menu at the top of the Reference page I linked), and the Release Notes for the 6.28.xx series don’t mention this change …

TF1 drawing issue in ROOT versions > 6.28.10

ROOT

dastudillo August 29, 2026, 4:06am 3

Increase the number of points in x where the TF1 are drawn, e.g. to 500 (f1->SetNpx(500); etc), so that there are enough points in the small range you are plotting them.