de.lmu.ifi.dbs.elki.math.linearalgebra.pca
Class PercentageEigenPairFilter

java.lang.Object
  de.lmu.ifi.dbs.elki.logging.AbstractLoggable
      de.lmu.ifi.dbs.elki.math.linearalgebra.pca.PercentageEigenPairFilter

All Implemented Interfaces:

EigenPairFilter, Parameterizable

@Title(value="Percentage based Eigenpair filter")
@Description(value="Sorts the eigenpairs in decending order of their eigenvalues and returns the first eigenpairs, whose sum of eigenvalues is higher than the given percentage of the sum of all eigenvalues.")
public class PercentageEigenPairFilter
extends AbstractLoggable
implements EigenPairFilter, Parameterizable

The PercentageEigenPairFilter sorts the eigenpairs in descending order of their eigenvalues and marks the first eigenpairs, whose sum of eigenvalues is higher than the given percentage of the sum of all eigenvalues as strong eigenpairs.

Author:

Elke Achtert

Field Summary

private double	alpha The threshold for strong eigenvectors: the strong eigenvectors explain a portion of at least alpha of the total variance.
static OptionID	ALPHA_ID OptionID for ALPHA_PARAM
private DoubleParameter	ALPHA_PARAM The threshold for 'strong' eigenvectors: the 'strong' eigenvectors explain a portion of at least alpha of the total variance.
static double	DEFAULT_ALPHA The default value for alpha.

Fields inherited from class de.lmu.ifi.dbs.elki.logging.AbstractLoggable

debug, logger

Constructor Summary

PercentageEigenPairFilter(Parameterization config)
Constructor, adhering to Parameterizable

Method Summary

FilteredEigenPairs

filter(SortedEigenPairs eigenPairs) Filters the specified eigenpairs into strong and weak eigenpairs, where strong eigenpairs having high variances and weak eigenpairs having small variances.

Methods inherited from class de.lmu.ifi.dbs.elki.logging.AbstractLoggable

debugFine, debugFiner, debugFinest, exception, progress, verbose, warning

Methods inherited from class java.lang.Object

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

Field Detail

ALPHA_ID

public static final OptionID ALPHA_ID

OptionID for ALPHA_PARAM

DEFAULT_ALPHA

public static final double DEFAULT_ALPHA

The default value for alpha.

See Also:

Constant Field Values

ALPHA_PARAM

private final DoubleParameter ALPHA_PARAM

The threshold for 'strong' eigenvectors: the 'strong' eigenvectors explain a portion of at least alpha of the total variance.

Default value: DEFAULT_ALPHA

Key: -pca.filter.alpha

alpha

private double alpha

The threshold for strong eigenvectors: the strong eigenvectors explain a portion of at least alpha of the total variance.

Constructor Detail

PercentageEigenPairFilter

public PercentageEigenPairFilter(Parameterization config)

Constructor, adhering to Parameterizable

Parameters:

config - Parameterization

Method Detail

filter

public FilteredEigenPairs filter(SortedEigenPairs eigenPairs)

Description copied from interface: EigenPairFilter

Filters the specified eigenpairs into strong and weak eigenpairs, where strong eigenpairs having high variances and weak eigenpairs having small variances.

Specified by:

filter in interface EigenPairFilter

Parameters:

eigenPairs - the eigenPairs (i.e. the eigenvectors and

Returns:

the filtered eigenpairs