org.lenskit.transform.normalize

Class IdentityVectorNormalizer

java.lang.Object

org.lenskit.transform.normalize.AbstractVectorNormalizer

org.lenskit.transform.normalize.IdentityVectorNormalizer

All Implemented Interfaces:

Serializable, VectorNormalizer

@Shareable
public class IdentityVectorNormalizer
extends AbstractVectorNormalizer
implements Serializable

Identity normalization (makes no change).

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
IdentityVectorNormalizer()

Method Summary

Modifier and Type	Method and Description
VectorTransformation	makeTransformation(Long2DoubleMap reference) Create a vector transformation that normalizes and denormalizes vectors with respect to a reference vector.
VectorTransformation	makeTransformation(SparseVector ratings) Create a vector transformation that normalizes and denormalizes vectors with respect to the specified entity.

Methods inherited from class org.lenskit.transform.normalize.AbstractVectorNormalizer

normalize

Methods inherited from class java.lang.Object

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

Constructor Detail

IdentityVectorNormalizer

public IdentityVectorNormalizer()

Method Detail

makeTransformation

public VectorTransformation makeTransformation(SparseVector ratings)

Description copied from interface: VectorNormalizer

Create a vector transformation that normalizes and denormalizes vectors with respect to the specified entity. This allows transformations to be applied multiple times to different vectors and also unapplied.

If the reference vector is empty, the returned transformation should be the identity transform. Results are undefined if the reference vector is not complete or contains NaN values.

If the normalization needs to retain a copy of the sparse vector, it will take an immutable copy.

Specified by:

makeTransformation in interface VectorNormalizer

Parameters:

ratings - The reference vector.

Returns:

A transformation built from the reference vector.

makeTransformation

public VectorTransformation makeTransformation(Long2DoubleMap reference)

Description copied from interface: VectorNormalizer

Create a vector transformation that normalizes and denormalizes vectors with respect to a reference vector. The reference vector is used to compute any data needed for the normalization. For example, a mean-centering normalization will subtract the mean of the reference vector from any vector to which it is applied, and add back the reference mean when it is unapplied.

This allows transformations to be applied multiple times to different vectors and also unapplied.

If the reference vector is empty, the returned transformation should be the identity transform. Results are undefined if the reference vector is not complete or contains NaN values.

If the normalization needs to retain a copy of the sparse vector, it will take an immutable copy.

Specified by:

makeTransformation in interface VectorNormalizer

Parameters:

reference - The reference vector.

Returns:

A transformation built from the reference vector.