I'm having a little hard time understanding this specific feature selection algorithm.
Specifically, I am looking into maximum-relevance-minimum-redundancy method for feature selection.
If I have a feature matrix $\ X = \{x_1, x_2, ... , x_n\} , x_i \in R^D $
then I can compute mutual information between two specific individual features, but when talking about
relevance of that specific feature to a "class", in terms of mRMR algorithm,
what is exactly the definition of "class" ?