org.apache.mahout.cf.taste.recommender
Interface ItemBasedRecommender

All Superinterfaces:
Recommender, Refreshable
All Known Implementing Classes:
GenericBooleanPrefItemBasedRecommender, GenericItemBasedRecommender

public interface ItemBasedRecommender
extends Recommender

Interface implemented by "item-based" recommenders.


Method Summary
 List<RecommendedItem> mostSimilarItems(long[] itemIDs, int howMany)
           
 List<RecommendedItem> mostSimilarItems(long[] itemIDs, int howMany, boolean excludeItemIfNotSimilarToAll)
           
 List<RecommendedItem> mostSimilarItems(long[] itemIDs, int howMany, Rescorer<LongPair> rescorer)
           
 List<RecommendedItem> mostSimilarItems(long[] itemIDs, int howMany, Rescorer<LongPair> rescorer, boolean excludeItemIfNotSimilarToAll)
           
 List<RecommendedItem> mostSimilarItems(long itemID, int howMany)
           
 List<RecommendedItem> mostSimilarItems(long itemID, int howMany, Rescorer<LongPair> rescorer)
           
 List<RecommendedItem> recommendedBecause(long userID, long itemID, int howMany)
           Lists the items that were most influential in recommending a given item to a given user.
 
Methods inherited from interface org.apache.mahout.cf.taste.recommender.Recommender
estimatePreference, getDataModel, recommend, recommend, removePreference, setPreference
 
Methods inherited from interface org.apache.mahout.cf.taste.common.Refreshable
refresh
 

Method Detail

mostSimilarItems

List<RecommendedItem> mostSimilarItems(long itemID,
                                       int howMany)
                                       throws TasteException
Parameters:
itemID - ID of item for which to find most similar other items
howMany - desired number of most similar items to find
Returns:
items most similar to the given item, ordered from most similar to least
Throws:
TasteException - if an error occurs while accessing the DataModel

mostSimilarItems

List<RecommendedItem> mostSimilarItems(long itemID,
                                       int howMany,
                                       Rescorer<LongPair> rescorer)
                                       throws TasteException
Parameters:
itemID - ID of item for which to find most similar other items
howMany - desired number of most similar items to find
rescorer - Rescorer which can adjust item-item similarity estimates used to determine most similar items
Returns:
itemss most similar to the given item, ordered from most similar to least
Throws:
TasteException - if an error occurs while accessing the DataModel

mostSimilarItems

List<RecommendedItem> mostSimilarItems(long[] itemIDs,
                                       int howMany)
                                       throws TasteException
Parameters:
itemIDs - IDs of item for which to find most similar other items
howMany - desired number of most similar items to find estimates used to determine most similar items
Returns:
items most similar to the given items, ordered from most similar to least
Throws:
TasteException - if an error occurs while accessing the DataModel

mostSimilarItems

List<RecommendedItem> mostSimilarItems(long[] itemIDs,
                                       int howMany,
                                       Rescorer<LongPair> rescorer)
                                       throws TasteException
Parameters:
itemIDs - IDs of item for which to find most similar other items
howMany - desired number of most similar items to find
rescorer - Rescorer which can adjust item-item similarity estimates used to determine most similar items
Returns:
items most similar to the given items, ordered from most similar to least
Throws:
TasteException - if an error occurs while accessing the DataModel

mostSimilarItems

List<RecommendedItem> mostSimilarItems(long[] itemIDs,
                                       int howMany,
                                       boolean excludeItemIfNotSimilarToAll)
                                       throws TasteException
Parameters:
itemIDs - IDs of item for which to find most similar other items
howMany - desired number of most similar items to find
excludeItemIfNotSimilarToAll - exclude an item if it is not similar to each of the input items
Returns:
items most similar to the given items, ordered from most similar to least
Throws:
TasteException - if an error occurs while accessing the DataModel

mostSimilarItems

List<RecommendedItem> mostSimilarItems(long[] itemIDs,
                                       int howMany,
                                       Rescorer<LongPair> rescorer,
                                       boolean excludeItemIfNotSimilarToAll)
                                       throws TasteException
Parameters:
itemIDs - IDs of item for which to find most similar other items
howMany - desired number of most similar items to find
rescorer - Rescorer which can adjust item-item similarity estimates used to determine most similar items
excludeItemIfNotSimilarToAll - exclude an item if it is not similar to each of the input items
Returns:
items most similar to the given items, ordered from most similar to least
Throws:
TasteException - if an error occurs while accessing the DataModel

recommendedBecause

List<RecommendedItem> recommendedBecause(long userID,
                                         long itemID,
                                         int howMany)
                                         throws TasteException

Lists the items that were most influential in recommending a given item to a given user. Exactly how this is determined is left to the implementation, but, generally this will return items that the user prefers and that are similar to the given item.

This returns a List of RecommendedItem which is a little misleading since it's returning recommending items, but, I thought it more natural to just reuse this class since it encapsulates an item and value. The value here does not necessarily have a consistent interpretation or expected range; it will be higher the more influential the item was in the recommendation.

Parameters:
userID - ID of user who was recommended the item
itemID - ID of item that was recommended
howMany - maximum number of items to return
Returns:
List of RecommendedItem, ordered from most influential in recommended the given item to least
Throws:
TasteException - if an error occurs while accessing the DataModel


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