de.lmu.ifi.dbs.elki.math.linearalgebra.pca.filter

Class WeakEigenPairFilter

java.lang.Object

de.lmu.ifi.dbs.elki.math.linearalgebra.pca.filter.WeakEigenPairFilter

All Implemented Interfaces:

EigenPairFilter

@Title(value="Weak Eigenpair Filter")
 @Description(value="Sorts the eigenpairs in decending order of their eigenvalues and returns those eigenpairs, whose eigenvalue is above the average (\'expected\') eigenvalue.")
public class WeakEigenPairFilter
extends java.lang.Object
implements EigenPairFilter

The WeakEigenPairFilter sorts the eigenpairs in descending order of their eigenvalues and returns the first eigenpairs who are above the average mark as "strong", the others as "weak".

Since:

0.2

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	WeakEigenPairFilter.Parameterizer Parameterization class.

Field Summary

Fields

Modifier and Type	Field and Description
static double	DEFAULT_WALPHA The default value for walpha.
private double	walpha The noise tolerance level for weak eigenvectors

Fields inherited from interface de.lmu.ifi.dbs.elki.math.linearalgebra.pca.filter.EigenPairFilter

PCA_EIGENPAIR_FILTER

Constructor Summary

Constructors

Constructor and Description
WeakEigenPairFilter(double walpha) Constructor.

Method Summary

Modifier and Type	Method and Description
int	filter(double[] eigenValues) Filters the specified eigenvalues into strong and weak eigenvalues, where strong eigenvalues have high variance and weak eigenvalues have small variance.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_WALPHA

public static final double DEFAULT_WALPHA

The default value for walpha.

See Also:

Constant Field Values

walpha

private double walpha

The noise tolerance level for weak eigenvectors

Constructor Detail

WeakEigenPairFilter

public WeakEigenPairFilter(double walpha)

Constructor.

Parameters:

walpha -

Method Detail

filter

public int filter(double[] eigenValues)

Description copied from interface: EigenPairFilter

Filters the specified eigenvalues into strong and weak eigenvalues, where strong eigenvalues have high variance and weak eigenvalues have small variance.

Specified by:

filter in interface EigenPairFilter

Parameters:

eigenValues - the array of eigenvalues, must be sorted descending

Returns:

the number of eigenvectors to keep