org.grouplens.lenskit.knn.item

Class ItemVectorSimilarity

java.lang.Object

org.grouplens.lenskit.knn.item.ItemVectorSimilarity

All Implemented Interfaces:

java.io.Serializable, ItemSimilarity

@Shareable
public class ItemVectorSimilarity
extends java.lang.Object
implements ItemSimilarity, java.io.Serializable

Implementation of ItemSimilarity that delegates to a vector similarity.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ItemVectorSimilarity(VectorSimilarity sim)

Method Summary

Modifier and Type	Method and Description
boolean	isSparse() Query whether this similarity is sparse.
boolean	isSymmetric() Query whether this similarity is symmetric.
double	similarity(long i1, SparseVector v1, long i2, SparseVector v2) Compute the similarity between two items.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ItemVectorSimilarity

@Inject
public ItemVectorSimilarity(VectorSimilarity sim)

Method Detail

similarity

public double similarity(long i1,
                         SparseVector v1,
                         long i2,
                         SparseVector v2)

Description copied from interface: ItemSimilarity

Compute the similarity between two items.

Specified by:

similarity in interface ItemSimilarity

Parameters:

i1 - The first item ID.

v1 - The first item vector.

i2 - The second item ID.

v2 - The second item vector.

Returns:

The similarity between the two items, in the range [0,1].

isSparse

public boolean isSparse()

Description copied from interface: ItemSimilarity

Query whether this similarity is sparse.

Specified by:

isSparse in interface ItemSimilarity

Returns:

true if the similarity function is sparse.

See Also:

VectorSimilarity.isSparse()

isSymmetric

public boolean isSymmetric()

Description copied from interface: ItemSimilarity

Query whether this similarity is symmetric.

Specified by:

isSymmetric in interface ItemSimilarity

Returns:

true if the similarity function is symmetric.

See Also:

VectorSimilarity.isSymmetric()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object