ndcg ( scores -- ndcg )
Statistics

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dcg ( scores -- dcg )

Vocabulary
math.statistics

Inputs

scores

a sequence

Outputs

ndcg

a number

Word description
Calculates the normalized discounted cumulative gain from a list of scores. The ndcg is the discounted cumulative gain divided by the theoretical maximum dcg for the given list.

See https://en.wikipedia.org/wiki/Discounted_cumulative_gain

See also
dcg

Definition

USING: kernel math sequences sorting ;

IN: math.statistics

: ndcg ( scores -- ndcg )
    [ 0.0 ] [
        dup dcg
        [ drop 0.0 ] [ swap sort <reversed> dcg /f ] if-zero
    ] if-empty ;