[SciPy-User] Alternatives to scipy.optimize

Christopher Jordan-Squire cjordan1@uw....
Sat Feb 25 14:07:45 CST 2012


On Sat, Feb 25, 2012 at 11:17 AM, Erik Petigura <eptune@gmail.com> wrote:
> Dear Scipy,
>
> Up until now, I've found the optimize module very useful.  Now, I'm finding
> that I need finer control.  I am fitting a model to data that is of the
> following from:
>
> model = func1(p1) + func2(p2)
>
> func1 is nonlinear in its parameters and func2 is linear in its parameters.
>
>
> There are two things I am struggling with:
>
> 1. I'd like to find the best fit parameters for func1 using an iterative
> approach (e.g. simplex algorithm that changes p1.).  At each iteration, I
> want to compute the optimum p2 by linear least squares in the interest of
> speed and robustness.
>

Are p1 and p2 coupled somehow? They must be, or computing p2 at each
iteration wouldn't be relevant.

This seems like a modification that could be made to the source code
without too much trouble, if iirc. Alternatively, you could possibly
use the callback option in fmin.

> 2. I'd also like the ability to hold certain parameters fixed in the
> optimization with out redefining my objective function each time.
>
>

Could you pass in a lambda function with those parameters fixed?

-Chris JS

> Is there another module you would recommend?  I've found openopt, but I
> wanted to get some guidance before I dive in to that.
>
> Erik
>
>
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