Referencing built-in CurveFit functions

Share icon

Thu, 11/24/2022 - 01:56 pm

I am sure I have seen the answer to this question before, but I cannot seem to turn it up:

 

Can I call the built-in CurveFit functions (eg. gauss, hillequation, etc) to generate values in a wave? Eg I'm looking for something like

wave w
wave coefficients

w=hillequation(coefficients,x)

 

though obviously that doesn't work.

As far as I know, this is not possible. But for some functions an equivalent command is available. For example, in case of Gaussian you can call

myoutput = Gauss1D(coefwave,x)

You can fake this however, by calling CurveFit with the 'only guess' option (/O) and a prepared coefficient wave. This, however, involves a graph for creating the output. You are better off with recreating the function in question (e.g., HillEquation) in most cases.

November 24, 2022 at 03:34 pm - Permalink

If you use the curve fitting dialog to perform a fit using settings that generate a fit wave, you can find in the history the assignment used to set the values of the fit wave from parameter values in w_coef. You can use this same assignment to generate values.

For a HillEquation fit you have:

fitwave = W_coef[0]+(W_coef[1]-W_coef[0])*(x^W_coef[2]/(x^W_coef[2]+W_coef[3]^W_coef[2]))

 

November 25, 2022 at 04:38 am - Permalink