[SciPy-user] fmin_cobyla hangs -- doesn't on windows!

Christian K. ckkart@hoc....
Wed Sep 5 00:29:42 CDT 2007


Christian K wrote:
> dmitrey wrote:
>> W/o code sample we can't say anything.
> 
> Sure. Some explanations on the code:
> The goal is to find a smooth baseline for scattered data f(x). Therefore I let
> fmin_cobyla minimize the difference between the data and a n-point spline
> subject to the constraint data-spline > 0. Additionally constraints on the first
> and second derivative are applied. To reduce minimisation time the difference
> and the derivatives are only calculated at a subset of the data points.
> 
> The strange thing is, that when running the minimisation separated from the
> application within which it is usually run, it still hangs, but under different
> conditions (different number of constraints). In the sample code the
> minimisation is repeated within a for loop while one parameter is changed (which
> is the number of points taken to calculate the difference). On my system, when
> run within the application, fmin_cobyla hangs for i=78, the stand alone script
> however hangs for i=15.
> 
> Script and data are attached.

I just noticed that it won't hang on windows (python 2.5, scipy 0.5.2, 
numpy 1.0.3). Or at least I haven't managed so far.

Christian



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