hi satra, what you observe seem to be a huge variance of the estimator.
I would smooth the fMRI data (I assume it is) to stabilize the anova feature selection. let me know if this helps Alex On Wed, Mar 14, 2012 at 9:27 PM, Satrajit Ghosh <[email protected]> wrote: > i have a situation i cannot quite comprehend. any suggestions would be much > appreciated. > > --- > clf = sk.svm.SVC(kernel='linear', shrinking=True) > anova_filter = SelectKBest(f_regression, k=50) > clf = Pipeline([('anova', anova_filter), ('svc', clf)]) > maxkfold = np.min(np.bincount(y1)[1:]) > result = [] > for train, test in cv.StratifiedKFold(y1, maxkfold): > result.append((y1[test], > clf.fit(X1[train], y1[train]).predict(X1[test]))) > --- > > with k=50 in the above anova filter i get the following confusion matrix > > [[ 0 7] > [ 0 10]] > > > with k=51 and greater, i get ( i love this - but i don't have much > confidence in it): > > [[7 0] > [1 9]] > > if i throw a Normalizer in the pipeline: > > clf = Pipeline([('xfm', Normalizer()), ('anova', anova_filter), ('svc', > clf)]) > > then i get the pattern with k=50 above independent of what i set k to. > > if i do shufflesplit it results in the same issues. > > cheers, > > satra > > > ------------------------------------------------------------------------------ > Virtualization & Cloud Management Using Capacity Planning > Cloud computing makes use of virtualization - but cloud computing > also focuses on allowing computing to be delivered as a service. > http://www.accelacomm.com/jaw/sfnl/114/51521223/ > _______________________________________________ > Scikit-learn-general mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/scikit-learn-general > ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Scikit-learn-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/scikit-learn-general
