org.apache.mahout.cf.taste.impl.recommender
Class RandomRecommender
java.lang.Object
org.apache.mahout.cf.taste.impl.recommender.AbstractRecommender
org.apache.mahout.cf.taste.impl.recommender.RandomRecommender
- All Implemented Interfaces:
- Refreshable, Recommender
public final class RandomRecommender
- extends AbstractRecommender
Produces random recommendations and preference estimates. This is likely only useful as a novelty and for
benchmarking.
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
RandomRecommender
public RandomRecommender(DataModel dataModel)
throws TasteException
- Throws:
TasteException
recommend
public List<RecommendedItem> recommend(long userID,
int howMany,
IDRescorer rescorer)
throws TasteException
- Parameters:
userID
- user for which recommendations are to be computedhowMany
- desired number of recommendationsrescorer
- rescoring function to apply before final list of recommendations is determined
- Returns:
List
of recommended RecommendedItem
s, ordered from most strongly recommend to
least
- Throws:
TasteException
- if an error occurs while accessing the DataModel
estimatePreference
public float estimatePreference(long userID,
long itemID)
- Parameters:
userID
- user ID whose preference is to be estimateditemID
- item ID to estimate preference for
- Returns:
- an estimated preference if the user has not expressed a preference for the item, or else the
user's actual preference for the item. If a preference cannot be estimated, returns
Double.NaN
refresh
public void refresh(Collection<Refreshable> alreadyRefreshed)
- Description copied from interface:
Refreshable
Triggers "refresh" -- whatever that means -- of the implementation. The general contract is that any
Refreshable
should always leave itself in a consistent, operational state, and that the refresh
atomically updates internal state from old to new.
- Parameters:
alreadyRefreshed
- Refreshable
s that are known to have already been
refreshed as a result of an initial call to a Refreshable.refresh(Collection)
method on some
object. This ensure that objects in a refresh dependency graph aren't refreshed twice
needlessly.
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