org.grouplens.lenskit.eval.traintest

Class OutputTopNMetric

java.lang.Object

org.grouplens.lenskit.eval.metrics.AbstractMetric<OutputTopNMetric.Context,Void,Void>

org.grouplens.lenskit.eval.traintest.OutputTopNMetric

All Implemented Interfaces:

Closeable, AutoCloseable, Metric<OutputTopNMetric.Context>

public class OutputTopNMetric
extends AbstractMetric<OutputTopNMetric.Context,Void,Void>

Top-N metric that writes recommendations to a file.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	OutputTopNMetric.Context
static class	OutputTopNMetric.Factory
static class	OutputTopNMetric.FactoryBuilder Configure the prediction output.

Constructor Summary

Constructors

Constructor and Description
OutputTopNMetric(org.grouplens.lenskit.eval.traintest.ExperimentOutputLayout layout, File file, int listSize, ItemSelector candidates, ItemSelector exclude)

Method Summary

Modifier and Type	Method and Description
void	close() Close the metric.
OutputTopNMetric.Context	createContext(Attributed algo, TTDataSet ds, Recommender rec) Create the context for an experimental condition (algorithm/data set pair).
Void	doMeasureUser(TestUser user, OutputTopNMetric.Context context) Measure a user with typed results.
protected Void	getTypedResults(OutputTopNMetric.Context context) Get the typed results from an accumulator.

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

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

OutputTopNMetric

public OutputTopNMetric(org.grouplens.lenskit.eval.traintest.ExperimentOutputLayout layout,
                        File file,
                        int listSize,
                        ItemSelector candidates,
                        ItemSelector exclude)
                 throws IOException

Throws:

IOException

Method Detail

createContext

public OutputTopNMetric.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 Void doMeasureUser(TestUser user,
                          OutputTopNMetric.Context context)

Description copied from class: AbstractMetric

Measure a user with typed results.

Specified by:

doMeasureUser in class AbstractMetric<OutputTopNMetric.Context,Void,Void>

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 Void getTypedResults(OutputTopNMetric.Context context)

Description copied from class: AbstractMetric

Get the typed results from an accumulator.

Specified by:

getTypedResults in class AbstractMetric<OutputTopNMetric.Context,Void,Void>

Parameters:

context - The context.

Returns:

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

close

public void close()
           throws IOException

Description copied from class: AbstractMetric

Close the metric. Many metrics do not need to be closed, so this implementation is a no-op.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class AbstractMetric<OutputTopNMetric.Context,Void,Void>

Throws:

IOException - if there is an error closing the metric.