Package elki.datasource.filter.normalization.columnwise

Class AttributeWiseCDFNormalization<V extends elki.data.NumberVector>

java.lang.Object

elki.datasource.filter.normalization.columnwise.AttributeWiseCDFNormalization<V>

Type Parameters:

V - vector type

All Implemented Interfaces:

Normalization<V>, elki.datasource.filter.ObjectFilter

Direct Known Subclasses:

AttributeWiseBetaNormalization

public class AttributeWiseCDFNormalization<V extends elki.data.NumberVector>
extends java.lang.Object
implements Normalization<V>

Class to perform and undo a normalization on real vectors by estimating the distribution of values along each dimension independently, then rescaling objects to the cumulative density function (CDF) value at the original coordinate.

This process is for example also mentioned in section 3.4 of

Effects of Feature Normalization on Image Retrieval
S. Aksoy, R. M. Haralick

but they do not detail how to obtain an appropriate function `F`.

Since:

0.6.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AttributeWiseCDFNormalization.Par<V extends elki.data.NumberVector>	Parameterization class.

Field Summary

Fields

Modifier and Type	Field	Description
protected java.util.List<elki.math.statistics.distribution.Distribution>	dists	Stores the estimated distributions
protected java.util.List<? extends elki.math.statistics.distribution.estimator.DistributionEstimator<?>>	estimators	Stores the distribution estimators
protected elki.data.NumberVector.Factory<V>	factory	Number vector factory.
private static elki.logging.Logging	LOG	Class logger.

Constructor Summary

Constructors

Constructor	Description
AttributeWiseCDFNormalization(java.util.List<? extends elki.math.statistics.distribution.estimator.DistributionEstimator<?>> estimators)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected boolean	constantZero(java.util.List<V> column, AttributeWiseCDFNormalization.Adapter adapter)	Test if an attribute is constant zero.
elki.datasource.bundle.MultipleObjectsBundle	filter(elki.datasource.bundle.MultipleObjectsBundle objects)
protected elki.math.statistics.distribution.Distribution	findBestFit(java.util.List<V> col, AttributeWiseCDFNormalization.Adapter adapter, int d, double[] test)	Find the best fitting distribution.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface elki.datasource.filter.normalization.Normalization

restore, transform

Field Detail

LOG

private static final elki.logging.Logging LOG

Class logger.

estimators

protected java.util.List<? extends elki.math.statistics.distribution.estimator.DistributionEstimator<?>> estimators

Stores the distribution estimators

dists

protected java.util.List<elki.math.statistics.distribution.Distribution> dists

Stores the estimated distributions

factory

protected elki.data.NumberVector.Factory<V extends elki.data.NumberVector> factory

Number vector factory.

Constructor Detail

AttributeWiseCDFNormalization

public AttributeWiseCDFNormalization(java.util.List<? extends elki.math.statistics.distribution.estimator.DistributionEstimator<?>> estimators)

Constructor.

Parameters:

estimators - Distribution estimators

Method Detail

filter

public elki.datasource.bundle.MultipleObjectsBundle filter(elki.datasource.bundle.MultipleObjectsBundle objects)

Specified by:

filter in interface elki.datasource.filter.ObjectFilter

findBestFit

protected elki.math.statistics.distribution.Distribution findBestFit(java.util.List<V> col,
                                                                     AttributeWiseCDFNormalization.Adapter adapter,
                                                                     int d,
                                                                     double[] test)

Find the best fitting distribution.

Parameters:

col - Column of table

adapter - Adapter for accessing the data

d - Dimension

test - Scatch space for testing goodness of fit

Returns:

Best fit distribution

constantZero

protected boolean constantZero(java.util.List<V> column,
                               AttributeWiseCDFNormalization.Adapter adapter)

Test if an attribute is constant zero.

Parameters:

column - Column

adapter - Data accessor.

Returns:

true if all values are zero

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object