org.lenskit.bias

Interface BiasModel

All Known Implementing Classes:

GlobalBiasModel, ItemBiasModel, LiveUserItemBiasModel, UserBiasModel, UserItemBiasModel

public interface BiasModel

Interface for bias models that can be based on the user, item, or both.

Method Summary

Modifier and Type	Method and Description
double	getIntercept() Get the global bias (intercept).
double	getItemBias(long item) Get the item bias.
Long2DoubleMap	getItemBiases(LongSet items) Get a set of item biases.
double	getUserBias(long user) Get the user bias.
Long2DoubleMap	getUserBiases(LongSet users) Get a set of user biases.

Method Detail

getIntercept

double getIntercept()

Get the global bias (intercept).

Returns:

The global bias.

getUserBias

double getUserBias(long user)

Get the user bias.

Parameters:

user - The user ID.

Returns:

The bias for the specified user, or 0 if the user’s bias is unknown.

getUserBiases

Long2DoubleMap getUserBiases(LongSet users)

Get a set of user biases.

Parameters:

users - The users whose biases are to be returned.

Returns:

A mapping from user IDs to biases. It is not guaranteed to contain all user IDs in its key set, but its Long2DoubleFunction.defaultReturnValue() will be 0.

getItemBias

double getItemBias(long item)

Get the item bias.

Parameters:

item - The item ID.

Returns:

The bias for the specified ite, or 0 if the item’s bias is unknown.

getItemBiases

Long2DoubleMap getItemBiases(LongSet items)

Get a set of item biases.

Parameters:

items - The items whose biases are to be returned.

Returns:

A mapping from item IDs to biases. It is not guaranteed to contain all item IDs in its key set, but its Long2DoubleFunction.defaultReturnValue() will be 0.