org.grouplens.lenskit.transform.normalize

Class DefaultItemVectorNormalizer

java.lang.Object

org.grouplens.lenskit.transform.normalize.DefaultItemVectorNormalizer

All Implemented Interfaces:

Serializable, ItemVectorNormalizer

@Shareable
public class DefaultItemVectorNormalizer
extends Object
implements ItemVectorNormalizer, Serializable

Default item vector normalizer that delegates to a generic VectorNormalizer.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected VectorNormalizer	delegate

Constructor Summary

Constructors

Constructor and Description
DefaultItemVectorNormalizer() Construct a new item vector normalizer that uses the identity normalization.
DefaultItemVectorNormalizer(VectorNormalizer norm) Construct a new item vector normalizer wrapping a generic vector normalizer.

Method Summary

Modifier and Type	Method and Description
VectorTransformation	makeTransformation(long user, SparseVector vector) Make a vector transformation for an item.
MutableSparseVector	normalize(long user, SparseVector vector, MutableSparseVector target) Normalize a vector with respect to an item vector.

Methods inherited from class java.lang.Object

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

Field Detail

delegate

protected final VectorNormalizer delegate

Constructor Detail

DefaultItemVectorNormalizer

public DefaultItemVectorNormalizer()

Construct a new item vector normalizer that uses the identity normalization.

DefaultItemVectorNormalizer

@Inject
public DefaultItemVectorNormalizer(VectorNormalizer norm)

Construct a new item vector normalizer wrapping a generic vector normalizer.

Parameters:

norm - The generic normalizer to use.

Method Detail

normalize

public MutableSparseVector normalize(long user,
                                     @Nonnull
                                     SparseVector vector,
                                     @Nullable
                                     MutableSparseVector target)

Description copied from interface: ItemVectorNormalizer

Normalize a vector with respect to an item vector.

Specified by:

normalize in interface ItemVectorNormalizer

Parameters:

user - The item id to normalize a vector for.

vector - The item's vector for reference.

target - The vector to normalize. If null, the item vector is normalized.

Returns:

The target vector, if specified. Otherwise, a fresh mutable vector containing a normalized copy of the item vector is returned.

makeTransformation

public VectorTransformation makeTransformation(long user,
                                               SparseVector vector)

Description copied from interface: ItemVectorNormalizer

Make a vector transformation for an item. The resulting transformation will be applied to item vectors to normalize and denormalize them.

Specified by:

makeTransformation in interface ItemVectorNormalizer

Parameters:

user - The item id to normalize for.

vector - The item's vector to use as the reference vector.

Returns:

The vector transformaition normalizing for this item.