java - Google preconditions illegal Argument exception -

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i using mahout create basic recommender may application. data set not have preferences. here's how table looks likeenter image description here

here's how set mahout

  mysqljdbcdatamodel jdbcmodel2 = new mysqljdbcdatamodel(datasource,"user_viewed_song_statistics",                 "audio_fk","user_profile_fk","audio_fk","uvss_date_created");           itemsimilarity similarity = new loglikelihoodsimilarity(jdbcmodel2);         recommender recommender =              new genericbooleanprefitembasedrecommender(jdbcmodel2, similarity);         for(recommendeditem item: recommender.recommend(1, 1))            system.out.println(item);

however after running this. returned error

exception in thread "main" java.lang.illegalargumentexception     @ com.google.common.base.preconditions.checkargument(preconditions.java:72)     @ org.apache.mahout.math.stats.loglikelihood.loglikelihoodratio(loglikelihood.java:101)     @ org.apache.mahout.cf.taste.impl.similarity.loglikelihoodsimilarity.doitemsimilarity(loglikelihoodsimilarity.java:102)     @ org.apache.mahout.cf.taste.impl.similarity.loglikelihoodsimilarity.itemsimilarities(loglikelihoodsimilarity.java:90)     @ org.apache.mahout.cf.taste.impl.recommender.genericbooleanprefitembasedrecommender.doestimatepreference(genericbooleanprefitembasedrecommender.java:54)     @ org.apache.mahout.cf.taste.impl.recommender.genericitembasedrecommender$estimator.estimate(genericitembasedrecommender.java:312)     @ org.apache.mahout.cf.taste.impl.recommender.genericitembasedrecommender$estimator.estimate(genericitembasedrecommender.java:300)     @ org.apache.mahout.cf.taste.impl.recommender.topitems.gettopitems(topitems.java:65)     @ org.apache.mahout.cf.taste.impl.recommender.genericitembasedrecommender.recommend(genericitembasedrecommender.java:131)     @ org.apache.mahout.cf.taste.impl.recommender.abstractrecommender.recommend(abstractrecommender.java:63)     @ starter.main(starter.java:53)

you using non-preference item recommendation. similar question

and find weird returning type of exception. i've done this.

mysqlbooleanprefjdbcdatamodel jdbc = new mysqlbooleanprefjdbcdatamodel(datasource, table_name, user_id, item_id); cachingrecommender cachingrecommender = new cachingrecommender( new slopeonerecommender(jdbc));  // 5 recommendations user 3  list<recommendeditem> items = cachingrecommender.recommend(3, 5);   (recommendeditem item : items) {         system.out.println(item);   }

hope helps.


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