Estimating custom function parameters in Matlab

Question

I have a set of data, which is distributed like on the picture below.

It clearly looks, like a function:

k1*(1-e^(-t/T1))-k2*(1-e^(-t/T2)).

Is there a method provided in Matlab, to estimate parameters in this kind of function or do you have any ideas of estimating them in code to avoid doing it 'manually'? Thanks.

Answer 1

You're looking for non linear optimisation.

Check the curve fitting toolbox, never used it but it seems to have exponential fitting.

Otherwise you could define your own target function f(k1,k2,T1,T2) (usually the mean squared error between your desired curve and your data ). Then you apply an optimization algorithm to minimise the error ( fminsearch() works good enough ).