Trying to determine when my fit fails

[Wile_E_Coyote]

, orson1981 presented the output of "[url=https://root.cern.ch/root/html/ROOT__Fit__FitResult.html#ROOT__Fit__FitResult:IsValid]status.IsValid()There has been a slight confusion in the other thread → " which I interpreted as the output of “status.Status()”.

The real problem (as demonstrated in both threads) is that “status.Status()” returns 0, which means “success” while the verbose output clearly shows that it “failed”.

I’ve recently met similar problems with the default fitter which I reported here and which are still not fixed (they may be related):

TGraph2DErrors fit problems

Thanks for implementing it. I’ve found three problems when trying to use my own “fitting function” (the “U” fit option). In my “fitting function”, I try to retrieve the actual “fit options” using: Foption_t foption = TVirtualFitter::GetFitter()->GetFitOption(); but “foption” contains simply zeros, regardless of which “fit options” are really used. When I try “UW”, I always get “NDf = 0” in the output, but I get 115 when I then try: ((TF2*)(TVirtualFitter::GetFitter()->GetUserFunc()))->G…