Package elki.clustering.silhouette

Class FastMSC.Instance2

java.lang.Object

elki.clustering.silhouette.FastMSC.Instance2

Direct Known Subclasses:

FasterMSC.Instance2

Enclosing class:

FastMSC<O>

protected class FastMSC.Instance2
extends java.lang.Object

Simplified FastMSC clustering instance for k=2.

For k=2, we can use a much simpler logic.

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field	Description
protected WritableIntegerDataStore	assignment	Output cluster mapping.
protected DistanceQuery<?>	distQ	Distance function to use.
protected WritableDoubleDataStore	dm0	Distances to the first medoid.
protected WritableDoubleDataStore	dm1	Distances to the second medoid.
protected DBIDs	ids	Ids to process.

Constructor Summary

Constructors

Constructor	Description
Instance2(DistanceQuery<?> distQ, DBIDs ids, WritableIntegerDataStore assignment)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected double	assignToNearestCluster(ArrayDBIDs means)	Assign each object to the nearest cluster.
protected double	doSwap(ArrayDBIDs medoids, int b, DBIDRef j)	Assign each object to the nearest cluster when replacing one medoid.
protected void	findBestSwap(DBIDRef j, double[] ploss)	Compute the loss change when choosing j as new medoid.
protected double	run(ArrayModifiableDBIDs medoids, int maxiter)	Run the FastMSC optimization phase.
DoubleDataStore	silhouetteScores()	Get the silhouette scores per point (must be run() first)

Methods inherited from class java.lang.Object

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

Field Detail

ids

protected DBIDs ids

Ids to process.

distQ

protected DistanceQuery<?> distQ

Distance function to use.

dm0

protected WritableDoubleDataStore dm0

Distances to the first medoid.

dm1

protected WritableDoubleDataStore dm1

Distances to the second medoid.

assignment

protected WritableIntegerDataStore assignment

Output cluster mapping.

Constructor Detail

Instance2

public Instance2(DistanceQuery<?> distQ,
                 DBIDs ids,
                 WritableIntegerDataStore assignment)

Constructor.

Parameters:

distQ - Distance query

ids - IDs to process

assignment - Cluster assignment

Method Detail

run

protected double run(ArrayModifiableDBIDs medoids,
                     int maxiter)

Run the FastMSC optimization phase.

Parameters:

medoids - Initial medoids list

maxiter - Maximum number of iterations

Returns:

final medoid Silhouette

assignToNearestCluster

protected double assignToNearestCluster(ArrayDBIDs means)

Assign each object to the nearest cluster.

Parameters:

means - Cluster medoids

Returns:

loss

findBestSwap

protected void findBestSwap(DBIDRef j,
                            double[] ploss)

Compute the loss change when choosing j as new medoid.

Parameters:

j - New medoid

ploss - Loss array

doSwap

protected double doSwap(ArrayDBIDs medoids,
                        int b,
                        DBIDRef j)

Assign each object to the nearest cluster when replacing one medoid.

Parameters:

medoids - Cluster medoids

b - Medoid position index

j - New medoid

Returns:

medoid silhouette

silhouetteScores

public DoubleDataStore silhouetteScores()

Get the silhouette scores per point (must be run() first)

Returns:

Silhouette scores