edu.stanford.nlp.cluster
Class PDDP

java.lang.Object
  |
  +--edu.stanford.nlp.cluster.AbstractClusteringMethod
        |
        +--edu.stanford.nlp.cluster.PDDP

All Implemented Interfaces:

ClusteringMethod

public class PDDP

extends AbstractClusteringMethod

Principal Direction Divisive Partitioning. PDDP (Boley, 1999) uses iterative splitting. It splits each partition by the hyperplane orthogonal to the principal direction.

Field Summary

protected cern.colt.matrix.DoubleMatrix2D	featurematrix
protected cern.colt.matrix.DoubleMatrix2D	submatrix

Fields inherited from class edu.stanford.nlp.cluster.AbstractClusteringMethod

clusters, db, method, nc, nd, nt

Constructor Summary

PDDP()

Method Summary

HHCluster	chooseNext() Chooses the next cluster to split.
SimpleClusters	cluster(DataCollection data, int num_clusters) Performs clustering algorithm, and populates Clusters
void	initialize()
void	split(HHCluster cluster) Splits cluster along the hyperplane orthogonal to the principal direction of the cluster.

Methods inherited from class edu.stanford.nlp.cluster.AbstractClusteringMethod

cluster, evaluate, evaluate, initialize, toString, toXMLString

Methods inherited from class java.lang.Object

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

Field Detail

featurematrix

protected cern.colt.matrix.DoubleMatrix2D featurematrix

submatrix

protected cern.colt.matrix.DoubleMatrix2D submatrix

Constructor Detail

PDDP

public PDDP()

Method Detail

initialize

public void initialize()

split

public void split(HHCluster cluster)

Splits cluster along the hyperplane orthogonal to the principal direction of the cluster. Adds both children to Clusters.

chooseNext

public HHCluster chooseNext()

Chooses the next cluster to split. It does this by finding the cluster with the highest scatter value. Returns most scattered cluster

cluster

public SimpleClusters cluster(DataCollection data,
                              int num_clusters)

Description copied from interface: ClusteringMethod

Performs clustering algorithm, and populates Clusters