org.apache.mahout.cf.taste.impl.recommender
Class GenericBooleanPrefItemBasedRecommender

java.lang.Object
  extended by org.apache.mahout.cf.taste.impl.recommender.AbstractRecommender
      extended by org.apache.mahout.cf.taste.impl.recommender.GenericItemBasedRecommender
          extended by org.apache.mahout.cf.taste.impl.recommender.GenericBooleanPrefItemBasedRecommender
All Implemented Interfaces:
Refreshable, ItemBasedRecommender, Recommender

public final class GenericBooleanPrefItemBasedRecommender
extends GenericItemBasedRecommender

A variant on GenericItemBasedRecommender which is appropriate for use when no notion of preference value exists in the data.

See Also:
GenericBooleanPrefUserBasedRecommender

Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.mahout.cf.taste.impl.recommender.GenericItemBasedRecommender
GenericItemBasedRecommender.MostSimilarEstimator
 
Constructor Summary
GenericBooleanPrefItemBasedRecommender(DataModel dataModel, ItemSimilarity similarity)
           
GenericBooleanPrefItemBasedRecommender(DataModel dataModel, ItemSimilarity similarity, CandidateItemsStrategy candidateItemsStrategy, MostSimilarItemsCandidateItemsStrategy mostSimilarItemsCandidateItemsStrategy)
           
 
Method Summary
protected  float doEstimatePreference(long userID, PreferenceArray preferencesFromUser, long itemID)
          This computation is in a technical sense, wrong, since in the domain of "boolean preference users" where all preference values are 1, this method should only ever return 1.0 or NaN.
 String toString()
           
 
Methods inherited from class org.apache.mahout.cf.taste.impl.recommender.GenericItemBasedRecommender
estimatePreference, getDefaultMostSimilarItemsCandidateItemsStrategy, getSimilarity, mostSimilarItems, mostSimilarItems, mostSimilarItems, mostSimilarItems, mostSimilarItems, mostSimilarItems, recommend, recommendedBecause, refresh
 
Methods inherited from class org.apache.mahout.cf.taste.impl.recommender.AbstractRecommender
getAllOtherItems, getDataModel, getDefaultCandidateItemsStrategy, recommend, removePreference, setPreference
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.apache.mahout.cf.taste.recommender.Recommender
getDataModel, recommend, removePreference, setPreference
 

Constructor Detail

GenericBooleanPrefItemBasedRecommender

public GenericBooleanPrefItemBasedRecommender(DataModel dataModel,
                                              ItemSimilarity similarity)

GenericBooleanPrefItemBasedRecommender

public GenericBooleanPrefItemBasedRecommender(DataModel dataModel,
                                              ItemSimilarity similarity,
                                              CandidateItemsStrategy candidateItemsStrategy,
                                              MostSimilarItemsCandidateItemsStrategy mostSimilarItemsCandidateItemsStrategy)
Method Detail

doEstimatePreference

protected float doEstimatePreference(long userID,
                                     PreferenceArray preferencesFromUser,
                                     long itemID)
                              throws TasteException
This computation is in a technical sense, wrong, since in the domain of "boolean preference users" where all preference values are 1, this method should only ever return 1.0 or NaN. This isn't terribly useful however since it means results can't be ranked by preference value (all are 1). So instead this returns a sum of similarities.

Overrides:
doEstimatePreference in class GenericItemBasedRecommender
Throws:
TasteException

toString

public String toString()
Overrides:
toString in class GenericItemBasedRecommender


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