org.grouplens.lenskit.eval.metrics.predict

Class EntropyPredictMetric

java.lang.Object

org.grouplens.lenskit.eval.metrics.AbstractMetric<EntropyPredictMetric.Context,EntropyPredictMetric.EntropyResult,EntropyPredictMetric.EntropyResult>

org.grouplens.lenskit.eval.metrics.predict.EntropyPredictMetric

All Implemented Interfaces:

Closeable, AutoCloseable, Metric<EntropyPredictMetric.Context>

public class EntropyPredictMetric
extends AbstractMetric<EntropyPredictMetric.Context,EntropyPredictMetric.EntropyResult,EntropyPredictMetric.EntropyResult>

Evaluate a recommender's prediction accuracy by computing the mutual information between the ratings and the prediction. This tells us the amount of information our predictions can tell the user about our ratings.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	EntropyPredictMetric.Context
static class	EntropyPredictMetric.EntropyResult

Constructor Summary

Constructors

Constructor and Description
EntropyPredictMetric()

Method Summary

Modifier and Type	Method and Description
EntropyPredictMetric.Context	createContext(Attributed algorithm, TTDataSet dataSet, Recommender rec) Create the context for an experimental condition (algorithm/data set pair).
EntropyPredictMetric.EntropyResult	doMeasureUser(TestUser user, EntropyPredictMetric.Context context) Measure a user with typed results.
protected EntropyPredictMetric.EntropyResult	getTypedResults(EntropyPredictMetric.Context context) Get the typed results from an accumulator.

Methods inherited from class org.grouplens.lenskit.eval.metrics.AbstractMetric

close, getColumnLabels, getPrefix, getResults, getSuffix, getUserColumnLabels, measureUser

Methods inherited from class java.lang.Object

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

Constructor Detail

EntropyPredictMetric

public EntropyPredictMetric()

Method Detail

createContext

public EntropyPredictMetric.Context createContext(Attributed algorithm,
                                                  TTDataSet dataSet,
                                                  Recommender rec)

Description copied from interface: Metric

Create the context for an experimental condition (algorithm/data set pair).

Parameters:

algorithm - The algorithm.

dataSet - The data set.

rec - The LensKit recommender, if applicable. This can be null for an external algorithm that does not provide a LensKit recommender.

Returns:

The accumulator. This will be passed to Metric.measureUser(TestUser, Object). If the metric does not accumulate any results, this method can return null.

doMeasureUser

public EntropyPredictMetric.EntropyResult doMeasureUser(TestUser user,
                                                        EntropyPredictMetric.Context context)

Description copied from class: AbstractMetric

Measure a user with typed results.

Specified by:

doMeasureUser in class AbstractMetric<EntropyPredictMetric.Context,EntropyPredictMetric.EntropyResult,EntropyPredictMetric.EntropyResult>

Parameters:

user - The user to measure.

context - The context.

Returns:

The results of measuring the user, or null to emit NAs for the user.

getTypedResults

protected EntropyPredictMetric.EntropyResult getTypedResults(EntropyPredictMetric.Context context)

Description copied from class: AbstractMetric

Get the typed results from an accumulator.

Specified by:

getTypedResults in class AbstractMetric<EntropyPredictMetric.Context,EntropyPredictMetric.EntropyResult,EntropyPredictMetric.EntropyResult>

Parameters:

context - The context.

Returns:

The results accumulated for this experiment, or null to emit NAs.