org.lenskit.knn.item.model

Class ItemItemBuildContext

java.lang.Object

org.lenskit.knn.item.model.ItemItemBuildContext

All Implemented Interfaces:

java.io.Serializable

@DefaultProvider(value=ItemItemBuildContextProvider.class)
 @Shareable
public class ItemItemBuildContext
extends java.lang.Object
implements java.io.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:

ItemItemModelProvider, Serialized Form

Method Summary

Modifier and Type	Method and Description
LongSortedSet	getItems() Get the set of items.
LongSortedSet	getUserItems(long user) Get the items rated by a particular user.
Long2DoubleSortedMap	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 Long2DoubleSortedMap itemVector(long item)

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

Parameters:

item - The item to query.

Returns:

The rating vector for item.

Throws:

java.lang.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.