[pymvpa] FeatureSelectionClassifier (in RFE) occasionally returns full features set

[Yaroslav Halchenko]

at first I thought that I know what is the reason, but then I realized
that it shouldn't be... didn't test though. to expedite things would you
mind uploading your data + code to the address I will provide you in a
followup email? ;)

On Sat, 25 Apr 2009, Vadim Axel wrote:

>    Hi,
>    I implemented some simple RFE logic, similar to what was described
>    here: [1]http://www.pymvpa.org/featsel.html
>    At the end of the classification procedure, I verify the the features
>    that were selected based on what was described here:
>    [2]http://www.pymvpa.org/faq.html#how-do-i-know-which-features-were-fin
>    ally-selected-by-a-classifier-doing-feature-selection
>    Now the problem: sometimes the resulted number of selected features is
>    the exact number, which is required (I use FixedNElementTailSelector),
>    whereas in some other case, for completely unknown reason, I get full
>    set of features. The issue is really weired, since for two sessions of
>    a subject I get selected feature set, but for two other sessions of the
>    same subject I get full feature set. I suspect, that the problem might
>    be in updating the feature_ids variable and not with classification,
>    because the classification error rate was pretty low.
>    Attached my code. Is it any problem with it?
>    I can also upload my dataset (~50 Mb zip). I didn't succeed to
>    reproduce it with smaller amount of data.
>    Thanks for your help,
>    Vadim

> Ссылки

>    1. http://www.pymvpa.org/featsel.html
>    2. http://www.pymvpa.org/faq.html#how-do-i-know-which-features-were-finally-selected-by-a-classifier-doing-feature-selection


-- 
Yaroslav Halchenko
Research Assistant, Psychology Department, Rutgers-Newark
Student  Ph.D. @ CS Dept. NJIT
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