org.apache.mahout.clustering.evaluation
Class ClusterEvaluator

java.lang.Object
  extended by org.apache.mahout.clustering.evaluation.ClusterEvaluator

public class ClusterEvaluator
extends Object


Constructor Summary
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
 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


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