# To what extent can NonlinearModelFit be sped up?

Can NonlinearModelFit be parallelized or compiled to allow one to achieve a scalable speedup for a fitting procedure? Attempting to use this function to fit a bivariate Gaussian (with a decent guess for initial conditions) can take upwards of a second.

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Not really, no. NonLinearModelFit uses FindFit which uses FindMinimum, and this function is well optimized. If none of the FindMinimum methods gives you a solution quickly enough (by which I mean: try them all, including a reasonable selection of suboptions) then I suppose it'll be quite difficult to achieve a speed-up any other way. –  Oleksandr R. Jun 26 '13 at 10:50
@OleksandrR. it depends. If the OP would be a little more open and post some code, there might be an issue with the optimizer for instance (catchword NIntegrate etc.) –  Stefan Jun 26 '13 at 12:46
@Stefan Apologies, I didn't mean to be cagey about anything. My question here just has to do with a previous question of mine asking about how to best do a 2D Gaussian fit: mathematica.stackexchange.com/questions/27642/… –  Bob Jun 26 '13 at 13:08
@Stefan yes, you're right of course. It's only because OP's questions so far have all been so vague that I thought the easiest approach was just to assume a sensible approach is being taken and say no rather than painfully try to extract more details such as, I don't know, what the function being fitted actually is. –  Oleksandr R. Jun 26 '13 at 14:23