org.lenskit.data.ratings

Class PackedRatingMatrix

java.lang.Object

org.lenskit.data.ratings.PackedRatingMatrix

All Implemented Interfaces:

RatingMatrix

@DefaultProvider(value=PackedRatingMatrixProvider.class)
 @Shareable
public class PackedRatingMatrix
extends java.lang.Object
implements RatingMatrix

An in-memory snapshot of rating data stored in packed arrays.

Method Summary

Modifier and Type	Method and Description
void	dispose() Dispose of the internal memory in the packed rating matrix.
LongCollection	getItemIds() Get the set of item IDs in the snapshot.
java.util.List<RatingMatrixEntry>	getRatings() Get the collection of ratings in the snapshot.
LongCollection	getUserIds() Get the set of user IDs in the snapshot.
java.util.Collection<RatingMatrixEntry>	getUserRatings(long userId) Get the ratings for a particular user.
Long2DoubleMap	getUserRatingVector(long userId) Get the current preferences of a particular user as a vector.
KeyIndex	itemIndex() Get the item ID index.
KeyIndex	userIndex() Get the user ID index.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getUserIds

public LongCollection getUserIds()

Description copied from interface: RatingMatrix

Get the set of user IDs in the snapshot.

Specified by:

getUserIds in interface RatingMatrix

Returns:

A set of all known user IDs.

getItemIds

public LongCollection getItemIds()

Description copied from interface: RatingMatrix

Get the set of item IDs in the snapshot.

Specified by:

getItemIds in interface RatingMatrix

Returns:

A set of all known item IDs.

userIndex

public KeyIndex userIndex()

Description copied from interface: RatingMatrix

Get the user ID index.

Specified by:

userIndex in interface RatingMatrix

Returns:

The index mapping between user IDs and user indices.

itemIndex

public KeyIndex itemIndex()

Description copied from interface: RatingMatrix

Get the item ID index.

Specified by:

itemIndex in interface RatingMatrix

Returns:

The index mapping between user IDs and user indices.

getRatings

public java.util.List<RatingMatrixEntry> getRatings()

Description copied from interface: RatingMatrix

Get the collection of ratings in the snapshot. The ratings are returned in an undetermined order. It is guaranteed that no duplicate ratings appear - each (user,item) pair is rated at most once. Each preference’s index is also in the range [0,len), where len is the size of this collection.

Modifying the returned indexed preferences will not modify the underlying snapshot.

Specified by:

getRatings in interface RatingMatrix

Returns:

All ratings in the system.

getUserRatings

public java.util.Collection<RatingMatrixEntry> getUserRatings(long userId)

Description copied from interface: RatingMatrix

Get the ratings for a particular user. It is guaranteed that no duplicate ratings appear - each (user,item) pair is rated at most once.

Modifying the returned indexed preferences will not modify the underlying snapshot.

Specified by:

getUserRatings in interface RatingMatrix

Parameters:

userId - The user’s ID.

Returns:

The user’s ratings, or an empty collection if the user is unknown.

getUserRatingVector

public Long2DoubleMap getUserRatingVector(long userId)

Description copied from interface: RatingMatrix

Get the current preferences of a particular user as a vector.

Specified by:

getUserRatingVector in interface RatingMatrix

Parameters:

userId - The user’s ID.

Returns:

The user’s rating vector.

dispose

@PreDestroy
public void dispose()

Dispose of the internal memory in the packed rating matrix. It is not necessary to call this method, but it is present to free extra memory references early.