A Quick way to subract two TGraph's? [Solved]

I do have some TGraph objects of various sizes but in similar scales, and their versions smoothed with various algorithms.
Could anyone please give me an idea on how could I subtract pair of TGraphs to draw the smoothing residuals easily? I am trying to come up with “automatic” smoothing algo choice and parameters tuning criteria for some measured data at hand… :slight_smile:

Thank you very much in advance!

Sincerely,
Eugene.

OK, closed! It was easy, I just haven’t dealt w/TGraphs all that much before. GetPoint/SetPoint do all that is needed. Interpolation is useful if comparing two different ones. Sincere thanks to everyone!