org.grouplens.lenskit

Interface RatingPredictor

All Known Implementing Classes:

AbstractRatingPredictor, KnownRatingRatingPredictor, OrdRecRatingPredictor, QuantizedRatingPredictor, SimpleRatingPredictor

public interface RatingPredictor

Predict user ratings. A rating predictor is like an ItemScorer, but its output will be predicted ratings.

Compatibility

Public

Method Summary

Modifier and Type	Method and Description
SparseVector	predict(long user, Collection<Long> items) Predict the user's preference for a collection of items.
double	predict(long user, long item) Predict a user's rating for a single item.
void	predict(long user, MutableSparseVector predictions) Predict for items in a vector.

Method Detail

predict

double predict(long user,
               long item)

Predict a user's rating for a single item.

Parameters:

user - The user ID for whom to generate a prediction.

item - The item ID whose rating is to be predicted.

Returns:

The predicted preference, or Double.NaN if no preference can be predicted.

predict

@Nonnull
SparseVector predict(long user,
                              @Nonnull
                              Collection<Long> items)

Predict the user's preference for a collection of items.

Parameters:

user - The user ID for whom to generate predicts.

items - The items to predict for.

Returns:

A mapping from item IDs to predicted preference. This mapping may not contain all requested items.

predict

void predict(long user,
             @Nonnull
             MutableSparseVector predictions)

Predict for items in a vector. The key domain of the provided vector is the items whose predictions are requested, and the predict method sets the values for each item to its predict (or unsets it, if no prediction can be provided). The previous values are discarded.

Parameters:

user - The user ID.

predictions - The prediction output vector. Its key domain is the items to score.