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isaacsu/sim-distance.clj

Created May 14, 2012 22:26
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sim-distance in clojure
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sim-distance.clj
(defn sim-distance [critic1 critic2]
; work out movies that both critics have rated
(let [shared-movies
((fn [c1 c2]
(map #(first %) (filter #(c2 (first %)) c1))) critic1 critic2)]
; return 0 if they have no ratings in common
(if (= (count shared-movies) 0)
0
; compute distance
(/ 1 (+ 1 (reduce + (map #(expt (- (critic1 %) (critic2 %)) 2) shared-movies)))))))
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