org.apache.mahout.clustering.evaluation

Class ClusterEvaluator

java.lang.Object

org.apache.mahout.clustering.evaluation.ClusterEvaluator

public class ClusterEvaluator
extends Object

Constructor Summary

Constructors

Constructor and Description
ClusterEvaluator(org.apache.hadoop.conf.Configuration conf, org.apache.hadoop.fs.Path clustersIn) Initialize a new instance from job information
ClusterEvaluator(Map<Integer,List<VectorWritable>> representativePoints, List<Cluster> clusters, DistanceMeasure measure) For testing only

Method Summary

Methods

Modifier and Type	Method and Description
double	interClusterDensity() Computes the inter-cluster density as defined in "Mahout In Action"
Map<Integer,Vector>	interClusterDistances() Computes the inter-cluster distances
Vector	intraClusterDensities() Computes the intra-cluster densities for all clusters as the average distance of the representative points from each other
double	intraClusterDensity() Computes the average intra-cluster density as the average of each cluster's intra-cluster density

Methods inherited from class java.lang.Object

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

Constructor Detail

ClusterEvaluator

public ClusterEvaluator(Map<Integer,List<VectorWritable>> representativePoints,
                List<Cluster> clusters,
                DistanceMeasure measure)

For testing only

Parameters:

representativePoints - a Map> of representative points keyed by clusterId

clusters - a Map of the clusters keyed by clusterId

measure - an appropriate DistanceMeasure

ClusterEvaluator

public ClusterEvaluator(org.apache.hadoop.conf.Configuration conf,
                org.apache.hadoop.fs.Path clustersIn)

Initialize a new instance from job information

Parameters:

conf - a Configuration with appropriate parameters

clustersIn - a String path to the input clusters directory

Method Detail

interClusterDensity

public double interClusterDensity()

Computes the inter-cluster density as defined in "Mahout In Action"

Returns:

the interClusterDensity

interClusterDistances

public Map<Integer,Vector> interClusterDistances()

Computes the inter-cluster distances

Returns:

a Map

intraClusterDensity

public double intraClusterDensity()

Computes the average intra-cluster density as the average of each cluster's intra-cluster density

Returns:

the average intraClusterDensity

intraClusterDensities

public Vector intraClusterDensities()

Computes the intra-cluster densities for all clusters as the average distance of the representative points from each other

Returns:

a Vector of the intraClusterDensity of the representativePoints by clusterId