org.grouplens.lenskit.eval.metrics.predict

Class CoveragePredictMetric

java.lang.Object

org.grouplens.lenskit.eval.metrics.AbstractMetric<CoveragePredictMetric.Context,CoveragePredictMetric.AggregateCoverage,CoveragePredictMetric.Coverage>

org.grouplens.lenskit.eval.metrics.predict.CoveragePredictMetric

All Implemented Interfaces:

Closeable, AutoCloseable, Metric<CoveragePredictMetric.Context>

public class CoveragePredictMetric
extends AbstractMetric<CoveragePredictMetric.Context,CoveragePredictMetric.AggregateCoverage,CoveragePredictMetric.Coverage>

Simple evaluator that records user, rating and prediction counts and computes recommender coverage over the queried items.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CoveragePredictMetric.AggregateCoverage
class	CoveragePredictMetric.Context
static class	CoveragePredictMetric.Coverage

Constructor Summary

Constructors

Constructor and Description
CoveragePredictMetric()

Method Summary

Modifier and Type	Method and Description
CoveragePredictMetric.Context	createContext(Attributed algo, TTDataSet ds, Recommender rec) Create the context for an experimental condition (algorithm/data set pair).
CoveragePredictMetric.Coverage	doMeasureUser(TestUser user, CoveragePredictMetric.Context context) Measure a user with typed results.
protected CoveragePredictMetric.AggregateCoverage	getTypedResults(CoveragePredictMetric.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

CoveragePredictMetric

public CoveragePredictMetric()

Method Detail

createContext

public CoveragePredictMetric.Context createContext(Attributed algo,
                                                   TTDataSet ds,
                                                   Recommender rec)

Description copied from interface: Metric

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

Parameters:

algo - The algorithm.

ds - 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 CoveragePredictMetric.Coverage doMeasureUser(TestUser user,
                                                    CoveragePredictMetric.Context context)

Description copied from class: AbstractMetric

Measure a user with typed results.

Specified by:

doMeasureUser in class AbstractMetric<CoveragePredictMetric.Context,CoveragePredictMetric.AggregateCoverage,CoveragePredictMetric.Coverage>

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 CoveragePredictMetric.AggregateCoverage getTypedResults(CoveragePredictMetric.Context context)

Description copied from class: AbstractMetric

Get the typed results from an accumulator.

Specified by:

getTypedResults in class AbstractMetric<CoveragePredictMetric.Context,CoveragePredictMetric.AggregateCoverage,CoveragePredictMetric.Coverage>

Parameters:

context - The context.

Returns:

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