fitting inverse tangent function

[Deepak Arora]

Hi,

I am working on fitting a nonlinear function of form,

y=k1+arctan(k2*x) for a data set that I have. I have attached a vi that loads a file, let me extract some data from the file and then perform the plotting. I am not able to get a good fit at all. Any clues..?

Thanks,
Deepak

[altenbach]

You did not include any subVIs* or any data.

* (missing are at least: LabViewMeasurementfiles.vi, CurveFitting.VI. Are these from a toolkit?)

Your program is layed out as a worm. I would suggest a state machine instead.

[Darin.K]

In cases where the derivatives are simple I would bag the string model and use the nonlinear fit VI with a VI giving both f(x) and f'(x).