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

java.lang.Object
  de.lmu.ifi.dbs.elki.math.linearalgebra.pca.RelativeEigenPairFilter

All Implemented Interfaces:

EigenPairFilter, InspectionUtilFrequentlyScanned, Parameterizable

@Title(value="Relative 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 of the remaining eigenvectors.")
public class RelativeEigenPairFilter
extends Object
implements EigenPairFilter

The RelativeEigenPairFilter sorts the eigenpairs in descending order of their eigenvalues and marks the first eigenpairs who are a certain factor above the average of the remaining eigenvalues. It is closely related to the WeakEigenPairFilter, and differs mostly by comparing to the remaining Eigenvalues, not to the total sum. There are some situations where one or the other is superior, especially when it comes to handling nested clusters and strong global correlations that are not too interesting. These benefits usually only make a difference at higher dimensionalities.

Nested Class Summary

static class

RelativeEigenPairFilter.Parameterizer Parameterization class.

Field Summary

static double	DEFAULT_RALPHA The default value for ralpha.
static OptionID	EIGENPAIR_FILTER_RALPHA Parameter relative alpha.
private double	ralpha The noise tolerance level for weak eigenvectors

Constructor Summary

RelativeEigenPairFilter(double ralpha)
Constructor.

Method Summary

FilteredEigenPairs

filter(SortedEigenPairs eigenPairs) Filter eigenpairs

Methods inherited from class java.lang.Object

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

Field Detail

EIGENPAIR_FILTER_RALPHA

public static final OptionID EIGENPAIR_FILTER_RALPHA

Parameter relative alpha.

DEFAULT_RALPHA

public static final double DEFAULT_RALPHA

The default value for ralpha.

See Also:

Constant Field Values

ralpha

private double ralpha

The noise tolerance level for weak eigenvectors

Constructor Detail

RelativeEigenPairFilter

public RelativeEigenPairFilter(double ralpha)

Constructor.

Parameters:

ralpha -

Method Detail

filter

public FilteredEigenPairs filter(SortedEigenPairs eigenPairs)

Filter eigenpairs

Specified by:

filter in interface EigenPairFilter

Parameters:

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

Returns:

the filtered eigenpairs