org.lenskit.eval.traintest.recommend

Class TopNMetric<X>

java.lang.Object

org.lenskit.eval.traintest.metrics.Metric<X>

org.lenskit.eval.traintest.recommend.TopNMetric<X>

Direct Known Subclasses:

ListOnlyTopNMetric

public abstract class TopNMetric<X>
extends Metric<X>

Base class for metrics that measure Top-N recommendations for users.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TopNMetric(java.lang.Class<? extends TypedMetricResult> resType, java.lang.Class<? extends TypedMetricResult> aggType) Construct a new result metric.
protected	TopNMetric(java.lang.Class<? extends TypedMetricResult> resType, java.lang.Class<? extends TypedMetricResult> aggType, java.lang.String suffix) Construct a new result metric.
protected	TopNMetric(java.util.List<java.lang.String> labels, java.util.List<java.lang.String> aggLabels) Construct a new result metric.

Method Summary

Modifier and Type	Method and Description
abstract MetricResult	measureUser(Recommender rec, TestUser user, int targetLength, ResultList recommendations, X context) Measure a single result.

Methods inherited from class org.lenskit.eval.traintest.metrics.Metric

createContext, getAggregateColumnLabels, getAggregateMeasurements, getColumnLabels, getRequiredRoots

Methods inherited from class java.lang.Object

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

Constructor Detail

TopNMetric

protected TopNMetric(java.util.List<java.lang.String> labels,
                     java.util.List<java.lang.String> aggLabels)

Construct a new result metric.

Parameters:

labels - Column labels.

aggLabels - Aggregate column labels.

TopNMetric

protected TopNMetric(java.lang.Class<? extends TypedMetricResult> resType,
                     java.lang.Class<? extends TypedMetricResult> aggType)

Construct a new result metric.

Parameters:

resType - The result type for measuring results, or null for no measurement.

aggType - The result type for aggregate measurements, or null for no measurement.

TopNMetric

protected TopNMetric(java.lang.Class<? extends TypedMetricResult> resType,
                     java.lang.Class<? extends TypedMetricResult> aggType,
                     java.lang.String suffix)

Construct a new result metric.

Parameters:

resType - The result type for measuring results, or null for no measurement.

aggType - The result type for aggregate measurements, or null for no measurement.

suffix - Suffix to apply to names.

Method Detail

measureUser

@Nonnull
public abstract MetricResult measureUser(Recommender rec,
                                                  TestUser user,
                                                  int targetLength,
                                                  ResultList recommendations,
                                                  X context)

Measure a single result. The result may come from either prediction or recommendation.

Thread Safety: This method may be called concurrently by multiple threads with the same recommender and context.

Parameters:

rec - The recommender used to recommend for this user.

user - The user’s test data.

targetLength - The intended length of the recommendation list.

recommendations - The user’s recommendations.

Returns:

A list of fields to add to the result’s output.