I used scikit.REFCV and mlxtend.SFS (backward) on the same data, same classifier, same cv, same scorer,... I also did a third version with sample weights passed to SFS's estimator
And i'm conflicted to see that many discrepencies. Should not the largest subsets have more or less same CV score, at least?
From my unterstanding, RFECV and SFS backward should work the same except the first one selects subset based on feature importance and the latter one on the metric provided.
Thanks for any input.