org.grouplens.lenskit.knn.item.model

Class ItemItemBuildContext

java.lang.Object

org.grouplens.lenskit.knn.item.model.ItemItemBuildContext

All Implemented Interfaces:

Serializable

@DefaultProvider(value=ItemItemBuildContextProvider.class)
 @Shareable
public class ItemItemBuildContext
extends Object
implements Serializable

Encapsulation of data needed during an item-item model build. This class provides access to item vectors and the item universe for use in building up the model in the accumulator.

This is shareable to make it more usable in the evaluator. Typical built models will not include it, and any dependencies on it should be Transient.

See Also:

ItemItemModelBuilder, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	ItemItemBuildContext.ItemVecPair A pair of item ids and their corresponding item vectors, avoiding (un)boxing the ids.

Method Summary

Modifier and Type	Method and Description
Iterator<ItemItemBuildContext.ItemVecPair>	getItemPairIterator() Deprecated. This will go away in LensKit 3.0.
Iterable<ItemItemBuildContext.ItemVecPair>	getItemPairs() Deprecated. This will go away in LensKit 3.0.
LongSortedSet	getItems() Get the set of items.
LongSortedSet	getUserItems(long user) Get the items rated by a particular user.
SparseVector	itemVector(long item) Get the rating vector for an item.

Methods inherited from class java.lang.Object

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

Method Detail

getItems

@Nonnull
public LongSortedSet getItems()

Get the set of items.

Returns:

The set of all items to build a model over.

itemVector

@Nonnull
public SparseVector itemVector(long item)

Get the rating vector for an item. Rating vectors contain normalized ratings, using the applicable VectorNormalizer on the user rating vectors.

Parameters:

item - The item to query.

Returns:

The rating vector for item.

Throws:

IllegalArgumentException - if item is not a valid item.

getUserItems

@Nonnull
public LongSortedSet getUserItems(long user)

Get the items rated by a particular user.

Parameters:

user - The user to query for.

Returns:

The items rated by user.

getItemPairs

@Deprecated
public Iterable<ItemItemBuildContext.ItemVecPair> getItemPairs()

Deprecated. This will go away in LensKit 3.0.

Provides an Iterable over ItemVecPairs

Returns:

An Iterable over ItemVecPairs, objects pairing item ids and their corresponding vectors.

getItemPairIterator

@Deprecated
public Iterator<ItemItemBuildContext.ItemVecPair> getItemPairIterator()

Deprecated. This will go away in LensKit 3.0.

Returns an Iterator over all item vector pairs.

Returns:

An Iterator over ItemVecPairs, an object offering public access to the item ids and their corresponding vectors.