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

java.lang.Object
  extended by 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

Release 0.4.0 (2011-09-20_1324)