Fitting with integral functions

[altenbach]

Yes, of course. This all takes place in the model VI, which just calculates the function based on all inputs. At this point, there is no distinction between fitting and fixed parameters.

(Depending on the problem, the numerical partial derivatives calculation might not be smooth enough, but you can test that.)

[photoon]

Hi, Matt and Christian,

I could implement the fitting with integral form of functions by using the method you suggested. But, I found out one problem which is related to absolute value.  When I used the abs function in the model vi, the fitting doesn't work. If you change it by removing the abs function, it works pretty well. I attach the two forms of the model function. If you have any idea, give me more advice.

[altenbach]

What is a typical x-range?

What are typical parameters?

Can you attach some data too?

What is the meaning of "does not work"? (wrong fit, specific error, computer burst into flames, etc.).

[photoon]

Hi,

I made a mistake when I thought I was creating two model functions which should be the same. But, these two models don't look the same. So, using absolution function in model vi may not be a problem anymore. 

Thank you for giving me a good solution.

Best,

Doogie