de.lmu.ifi.dbs.elki.algorithm.clustering.subspace.clique

Class CLIQUESubspace

java.lang.Object

de.lmu.ifi.dbs.elki.data.Subspace

de.lmu.ifi.dbs.elki.algorithm.clustering.subspace.clique.CLIQUESubspace

public class CLIQUESubspace
extends Subspace

Represents a subspace of the original data space in the CLIQUE algorithm.

Since:

0.1

Author:

Elke Achtert

Field Summary

Fields

Modifier and Type	Field and Description
static java.util.Comparator<CLIQUESubspace>	BY_COVERAGE A partial comparator for CLIQUESubspaces based on their coverage.
private int	coverage The coverage of this subspace, which is the number of all feature vectors that fall inside the dense units of this subspace.
private java.util.List<CLIQUEUnit>	denseUnits The dense units belonging to this subspace.

Fields inherited from class de.lmu.ifi.dbs.elki.data.Subspace

DIMENSION_COMPARATOR

Constructor Summary

Constructors

Constructor and Description
CLIQUESubspace(int dimension) Creates a new one-dimensional subspace of the original data space.
CLIQUESubspace(long[] dimensions) Creates a new k-dimensional subspace of the original data space.

Method Summary

Modifier and Type	Method and Description
void	addDenseUnit(CLIQUEUnit unit) Adds the specified dense unit to this subspace.
java.util.List<Pair<Subspace,ModifiableDBIDs>>	determineClusters() Determines all clusters in this subspace by performing a depth-first search algorithm to find connected dense units.
void	dfs(CLIQUEUnit unit, ModifiableDBIDs cluster, CLIQUESubspace model) Depth-first search algorithm to find connected dense units in this subspace that build a cluster.
int	getCoverage() Returns the coverage of this subspace, which is the number of all feature vectors that fall inside the dense units of this subspace.
CLIQUESubspace	join(CLIQUESubspace other, double all, double tau) Joins this subspace and its dense units with the specified subspace and its dense units.
protected CLIQUEUnit	leftNeighbor(CLIQUEUnit unit, int dim) Returns the left neighbor of the given unit in the specified dimension.
protected CLIQUEUnit	rightNeighbor(CLIQUEUnit unit, int dim) Returns the right neighbor of the given unit in the specified dimension.
java.lang.String	toString() Calls the super method and adds additionally the coverage, and the dense units of this subspace.

Methods inherited from class de.lmu.ifi.dbs.elki.data.Subspace

dimensionality, dimensionsToString, dimensonsToString, equals, getDimensions, hashCode, isSubspace, join, joinLastDimensions

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

denseUnits

private java.util.List<CLIQUEUnit> denseUnits

The dense units belonging to this subspace.

coverage

private int coverage

The coverage of this subspace, which is the number of all feature vectors that fall inside the dense units of this subspace.

BY_COVERAGE

public static java.util.Comparator<CLIQUESubspace> BY_COVERAGE

A partial comparator for CLIQUESubspaces based on their coverage. The CLIQUESubspaces are reverse ordered by the values of their coverage.

Compares the two specified CLIQUESubspaces for order. Returns a negative integer, zero, or a positive integer if the coverage of the first subspace is greater than, equal to, or less than the coverage of the second subspace. I.e. the subspaces are reverse ordered by the values of their coverage.

Note: this comparator provides an ordering that is inconsistent with equals.

Constructor Detail

CLIQUESubspace

public CLIQUESubspace(int dimension)

Creates a new one-dimensional subspace of the original data space.

Parameters:

dimension - the dimension building this subspace

CLIQUESubspace

public CLIQUESubspace(long[] dimensions)

Creates a new k-dimensional subspace of the original data space.

Parameters:

dimensions - the dimensions building this subspace

Method Detail

addDenseUnit

public void addDenseUnit(CLIQUEUnit unit)

Adds the specified dense unit to this subspace.

Parameters:

unit - the unit to be added.

determineClusters

public java.util.List<Pair<Subspace,ModifiableDBIDs>> determineClusters()

Determines all clusters in this subspace by performing a depth-first search algorithm to find connected dense units.

Returns:

the clusters in this subspace and the corresponding cluster models

dfs

public void dfs(CLIQUEUnit unit,
                ModifiableDBIDs cluster,
                CLIQUESubspace model)

Depth-first search algorithm to find connected dense units in this subspace that build a cluster. It starts with a unit, assigns it to a cluster and finds all units it is connected to.

Parameters:

unit - the unit

cluster - the IDs of the feature vectors of the current cluster

model - the model of the cluster

leftNeighbor

protected CLIQUEUnit leftNeighbor(CLIQUEUnit unit,
                                  int dim)

Returns the left neighbor of the given unit in the specified dimension.

Parameters:

unit - the unit to determine the left neighbor for

dim - the dimension

Returns:

the left neighbor of the given unit in the specified dimension

rightNeighbor

protected CLIQUEUnit rightNeighbor(CLIQUEUnit unit,
                                   int dim)

Returns the right neighbor of the given unit in the specified dimension.

Parameters:

unit - the unit to determine the right neighbor for

dim - the dimension

Returns:

the right neighbor of the given unit in the specified dimension

getCoverage

public int getCoverage()

Returns the coverage of this subspace, which is the number of all feature vectors that fall inside the dense units of this subspace.

Returns:

the coverage of this subspace

join

public CLIQUESubspace join(CLIQUESubspace other,
                           double all,
                           double tau)

Joins this subspace and its dense units with the specified subspace and its dense units. The join is only successful if both subspaces have the first k-1 dimensions in common (where k is the number of dimensions) and the last dimension of this subspace is less than the last dimension of the specified subspace.

Parameters:

other - the subspace to join

all - the overall number of feature vectors

tau - the density threshold for the selectivity of a unit

Returns:

the join of this subspace with the specified subspace if the join condition is fulfilled, null otherwise.

See Also:

Subspace.joinLastDimensions(de.lmu.ifi.dbs.elki.data.Subspace)

toString

public java.lang.String toString()

Calls the super method and adds additionally the coverage, and the dense units of this subspace.

Overrides:

toString in class Subspace