/*
* Carrot2 project.
*
* Copyright (C) 2002-2014, Dawid Weiss, Stanisław Osiński.
* All rights reserved.
*
* Refer to the full license file "carrot2.LICENSE"
* in the root folder of the repository checkout or at:
* http://www.carrot2.org/carrot2.LICENSE
*/
package org.carrot2.output.metrics;
import org.carrot2.core.Cluster;
import org.junit.Test;
import com.google.common.collect.Lists;
/**
* Test cases for {@link IClusteringMetric}.
*/
public class ContaminationMetricTest extends IdealPartitioningBasedMetricTest
{
@Test
public void testWorstCaseH()
{
assertThat(ContaminationMetric.calculateWorstCaseH(0, 1)).isEqualTo(0);
assertThat(ContaminationMetric.calculateWorstCaseH(1, 1)).isEqualTo(0);
assertThat(ContaminationMetric.calculateWorstCaseH(2, 1)).isEqualTo(0);
assertThat(ContaminationMetric.calculateWorstCaseH(2, 2)).isEqualTo(1);
assertThat(ContaminationMetric.calculateWorstCaseH(8, 4)).isEqualTo(24);
assertThat(ContaminationMetric.calculateWorstCaseH(6, 4)).isEqualTo(13);
}
@Test
public void testEmptyCluster()
{
check(new Cluster(), null);
}
@Test
public void testTrivialCluster()
{
check(new Cluster("test", documentWithPartitions("test")), 0.0);
}
@Test
public void testPureCluster()
{
check(pureCluster(), 0.0);
}
@Test
public void testPartiallyContaminatedCluster()
{
check(partiallyContaminatedCluster(), 0.75);
}
@Test
public void testFullyContaminatedCluster()
{
check(fullyContaminatedCluster(), 1.0);
}
@Test
public void testHardClustersWithOverlappingPartitions()
{
// Second cluster is fully contaminated even though it perfectly matches
// second partition. This is because the partition itself is "contaminated"
// by sharing one document with the first partition.
check(hardClustersWithOverlappingPartitions(), 0.0, 1.0);
}
@Test
public void testHardPartitionsOverlappingClusters()
{
check(overlappingClustersWithHardPartitions(), 1.0, 0.0);
}
@Test
public void testOverlappingPartitionsOverlappingClusters()
{
// Again, clusters are penalized because partitions themselves are
// "contaminated", see comment above.
check(overlappingClustersWithOverlappingPartitions(), 0.75, 1.0);
}
@Test
public void testAllDocumentsInOtherTopics()
{
final Cluster otherTopics = clusterWithPartitions("t1", "t2", "t3");
otherTopics.setOtherTopics(true);
check(otherTopics, null);
}
@Test
public void testIdealClustering()
{
check(idealClusters(), 0.0, 0.0);
}
private void check(Cluster cluster, Double expectedContamination)
{
check(new Cluster []
{
cluster
}, expectedContamination);
}
private void check(Cluster [] clusters, Double... expectedContaminations)
{
final ContaminationMetric metric = new ContaminationMetric();
metric.documents = getAllDocuments(clusters);
metric.clusters = Lists.newArrayList(clusters);
metric.calculate();
for (int i = 0; i < clusters.length; i++)
{
assertThat(
clusters[i].<Object> getAttribute(ContaminationMetric.CONTAMINATION))
.isEqualTo(expectedContaminations[i]);
}
}
@Override
protected String [] getClusterMetricKeys()
{
return new String []
{
ContaminationMetric.CONTAMINATION
};
}
}