org.grouplens.lenskit.transform.normalize

Interface ItemVectorNormalizer

All Known Implementing Classes:

DefaultItemVectorNormalizer

@DefaultImplementation(value=DefaultItemVectorNormalizer.class)
public interface ItemVectorNormalizer

Normalizes an item's vector.

Method Summary

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

Method Detail

normalize

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

Normalize a vector with respect to an item vector.

Parameters:

itemId - 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

VectorTransformation makeTransformation(long itemId,
                                        SparseVector vector)

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

Parameters:

itemId - 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.