I am using NonlinearModelFit for fitting a dataset to some complex numerical model function that depends on a few parameters. The final required precision of these parameters is very low, like 3 digits. The precision of data points is float, meaning 7-8 digits. The same is true for model function and it specifically returns the real number with precision set to 7 digits.
I try to tell this all to Mathematica with the call:
NonlinearModelFit[SetPrecision[points, 7], model[M, x, A, B], {M, A, B}, x, AccuracyGoal -> 3, PrecisionGoal -> 3, WorkingPrecision -> 7];
Nevertheless, NonlinearModelFit is trying a lot of different candidates for values of parameters, with very small step size, e.g. ~10^-10, which is lower than 10^-7. Since the model function is slow, I would like to avoid these unnecessary calls.
Is there any additional setting that would limit the minimum step size of NonlinearModelFit during a search for Best Fit Parameter values?
