How to fit an equation containing more that one variables?

[Wile_E_Coyote]

There is no “TGraph3D” in ROOT, so you will need to use a different approach, e.g.:

Minimization in PyROOT

Hi, The recommended way to minimise a function is to use the ROOT.Math.Minimizer class. There is this tutorial, ROOT: tutorials/fit/NumericalMinimization.C File Reference, but it is in C++. If you have issues translating it in Python, please let me know, I can provide that example also in Python Lorenzo

Another possibility would be to create a TH3? histogram and fit it with a TF3 fuction.