rankScore {rrecsys}

Rank Score

Description

Rank Score extends the recall metric to take the positions of correct items in a ranked list into account.

Usage

rankScore(recommendedIDX, testSetIDX, alpha)

Arguments

recommendedIDX

indices of the recommended items. Object of class numeric.

testSetIDX

indices of the items in the test set. Object of class numeric

alpha

is the ranking half life. Object of class numeric.

Details

Rank Score is defined as the ratio of the Rank Score of the correct items to best theoretical Rank Score achievable for the user:

rankscore_{p} =\sum_{i\in{h}} 2^{-\frac{rank(i)-1}{\alpha}}

rankscore_{max} = \sum_{i=1}^{|T|} 2^{-\frac{i-1}{\alpha}}

rankscore = \frac{rankscore_p}{rankscore_{max}}