mahout_user_recommender.clj

(ns mahout-test.recommend
  (:import [java.io File]
           [org.apache.mahout.cf.taste.model DataModel]
           [org.apache.mahout.cf.taste.impl.model.file FileDataModel]
           [org.apache.mahout.cf.taste.impl.similarity PearsonCorrelationSimilarity TanimotoCoefficientSimilarity LogLikelihoodSimilarity]
           [org.apache.mahout.cf.taste.impl.neighborhood NearestNUserNeighborhood ThresholdUserNeighborhood]
           [org.apache.mahout.cf.taste.impl.recommender GenericUserBasedRecommender GenericItemBasedRecommender]))

(defn create-user-recommender
  [file]
  (let [model (FileDataModel. file)
        similarity (LogLikelihoodSimilarity. model)]
    (GenericUserBasedRecommender. model
                                  (ThresholdUserNeighborhood. 0.5 similarity model)
                                  similarity)))

(defn recommend-user
  "Make n recommendations from file for user."
  [file user n]
  (.recommend (create-user-recommender file) user n))


(defn create-item-recommender
  [file]
  (let [model (FileDataModel. file)]
    (GenericItemBasedRecommender. model (LogLikelihoodSimilarity. model))))

(defn recommend-item
  "Make n recommendations from file for user."
  [file user n]
  (.recommend (create-item-recommender file) user n))

; user=> (map #(str (.getItemID %) " @" (.getValue %)) (recommend-user (File. "ratings.csv") 1 5)) 
; ("104 @4.257081" "106 @4.0")

; user=> (map #(str (.getItemID %) " @" (.getValue %)) (recommend-item (File. "ratings.csv") 1 5)) 
; ("104 @2.8088317" "106 @2.5915816" "105 @2.5748677")

ratings.csv