How to fit a desired function form to a set of data in MATLAB?

Dear All,

I just installed the curve fitting toolbox and have been trying to get familiar with how it works. Although my question is specifically addressing a real problem, it could be a general question with any arbitrary choice of functional form. Assume I have a desired functional form such as :

f(x) = D*(1 - exp(-a*x))^2

And I have the following data set of:

 X  Y
-0.55  2.3386639
-0.5  -15.554354
-0.45  -31.500773
-0.4  -45.661997
-0.35  -58.182891
-0.3  -69.179367
-0.25  -78.728997
-0.2  -86.859606
-0.15  -93.532515
-0.1  -98.620664
-0.05  -101.89666
0  -103.08067
0.05  -102.01361
0.1  -98.879876
0.15  -94.172935
0.2  -88.344847
0.25  -81.576677
0.3  -73.851215
0.35  -65.088782
0.4  -55.255995
0.45  -44.56707
0.5  -33.717314
0.55  -23.724423
0.6  -15.329395
0.65  -8.7090074
0.7  -3.7387088
0.75  -0.25488612
0.8  1.9270662
0.85  3.0617316
0.9  3.4563882
0.95  3.405915
1  3.1230416
1.05  2.706436
1.1  2.3402943
1.15  2.018794
1.2  1.7367674
1.25  1.4896294
1.3  1.2733121
1.35  1.0842074
1.4  0.91911626
1.45  0.77520246
1.5  0.64995259

I want to know how I can fit the given functional form to the provided set of data and find the coefficients a and D. Even though I know how to use polyfit, and simple exponential fitting in MATLAB, when it comes to complicated functional forms, I stuck in mug!!

I hope by your helps and assistance I will be able to follow a general strategy to fit any arbitrary functional forms to a given set of data. Thank you so much.

[nony lew]

Did you solve the problem? I have something similar to do and I do not know how. Thanks,

[Unai San Miguel]

Have you looked at the documentation of functions fit and fittype?