Scipy: difference between optimize.fmin and optimize.leastsq

Question

What's the difference between scipy's optimize.fmin and optimize.leastsq? They seem to be used in pretty much the same way in this example page. The only difference I can see is that leastsq actually calculates the sum of squares on its own (as its name would suggest) while when using fmin one has to do this manually. Other than that, are the two functions equivalent?

Answer 1

Different algorithms underneath.

fmin is using the simplex method; leastsq is using least squares fitting.