To fit experimental and theoretical data by using another function

Hi all,

I have a question regarding fitting of a graph. I cannot divulge too much information as it is confidential. But, I would try my best to clearly explain my question.

I have theoretical values of a function as an array of 501 elements. Also, I have corresponding experimental values, not for the entire range, but for intermediate steps (e.g.: experimental values for 1, 45, 100,....501). I have to fit both these arrays using another function X. The function X has 25 values. Each of these values can be adjusted to get the best fit of theoretical and experimental data. The adjustment can be from 0 to 1.00 in steps of 0.01. Changing each value will have a subsequent independent effect on the fit. I need to find the best 25 values of function X that could lead to the best fit of theoretical and experimental data.

I have searched online to get some information but I am still at the starting point and I am not sure about the way to approach this question.

Thanks a lot, Cheers, Srikanth.