Curve fitter app with custom function
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Hi, I have a gaussian function y=A*exp(-(x-mu).^2/(2*sigma^2)).
I want to use custom equation in curve fitter. The default setting in the custom equation is a*exp(-b*x)+c.
How should I key in mu and sigma in custom equation? I put "a*exp(-(x-b).^2/(2*c^2))" but the curve doesn't look correct.
I used Gaussian option with 'gauss2' and the curve looks fine but the equation for gauss2 is not exactly same as my custom function. that's why I want to use custom function. Please advise.
thanks.
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Accepted Answer
Walter Roberson
on 2 Sep 2022
If you are using cftool, then when you get to the place to enter the custom equation, you can just enter
A*exp(-(x-mu).^2/(2*sigma^2))
and it will estimate all of the parameters.
Note: you might want to consider adding a constant term to the equation.
6 Comments
Walter Roberson
on 6 Sep 2022
I would suggest constraining b1 as well to positive... keep constraining more variables to positive until you stop getting coefficients that cross 0 in the confidence bounds.
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