May

module yetilab.feature.feature;

vec = load yetilab.vector.vector;

fr = load yetilab.stream.framer;

// Utility functions for feature extractors

magdiff frame1 frame2 =

    sum (map2 do a b: abs(a - b) done (vec.list frame1) (vec.list frame2));

emptyFrameFor frames =

    vec.zeros

        if empty? frames then 0

        else vec.length (head frames)

        fi;

features featureFunc frames =

   (featuresOf prev frames =

        case frames of

        frame::rest: featureFunc prev frame :. \(featuresOf frame rest);

         _: [];

        esac;

    featuresOf (emptyFrameFor frames) frames);

{ magdiff, emptyFrameFor, features };