Package elki.datasource.filter.transform

Class ClassicMultidimensionalScalingTransform<I,O extends NumberVector>

java.lang.Object

elki.datasource.filter.transform.ClassicMultidimensionalScalingTransform<I,O>

Type Parameters:

I - Input data type

O - Output vector type

All Implemented Interfaces:

ObjectFilter

@Alias("mds")
public class ClassicMultidimensionalScalingTransform<I,O extends NumberVector>
extends java.lang.Object
implements ObjectFilter

Rescale the data set using multidimensional scaling, MDS. Note: the current implementation is rather expensive, both memory- and runtime wise. Don't use for large data sets! Instead, have a look at FastMultidimensionalScalingTransform which uses power iterations instead.

Since:

0.6.0

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field	Description
(package private) PrimitiveDistance<? super I>	dist	Distance function to use.
(package private) NumberVector.Factory<O>	factory	Vector factory.
private static Logging	LOG	Class logger.
(package private) int	tdim	Target dimensionality

Constructor Summary

Constructors

Constructor	Description
ClassicMultidimensionalScalingTransform(int tdim, PrimitiveDistance<? super I> dist, NumberVector.Factory<O> factory)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected static <I> double[][]	computeSquaredDistanceMatrix(java.util.List<I> col, PrimitiveDistance<? super I> dist)	Compute the squared distance matrix.
static void	doubleCenterSymmetric(double[][] m)	Double-center the given matrix (only upper triangle is used).
MultipleObjectsBundle	filter(MultipleObjectsBundle objects)	Filter a set of object packages.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final Logging LOG

Class logger.

dist

PrimitiveDistance<? super I> dist

Distance function to use.

tdim

int tdim

Target dimensionality

factory

NumberVector.Factory<O extends NumberVector> factory

Vector factory.

Constructor Detail

ClassicMultidimensionalScalingTransform

public ClassicMultidimensionalScalingTransform(int tdim,
                                               PrimitiveDistance<? super I> dist,
                                               NumberVector.Factory<O> factory)

Constructor.

Parameters:

tdim - Target dimensionality.

dist - Distance function to use.

factory - Vector factory.

Method Detail

filter

public MultipleObjectsBundle filter(MultipleObjectsBundle objects)

Description copied from interface: ObjectFilter

Filter a set of object packages.

Specified by:

filter in interface ObjectFilter

Parameters:

objects - Object to filter

Returns:

Filtered objects

computeSquaredDistanceMatrix

protected static <I> double[][] computeSquaredDistanceMatrix(java.util.List<I> col,
                                                             PrimitiveDistance<? super I> dist)

Compute the squared distance matrix.

Parameters:

col - Input data

dist - Distance function

Returns:

Distance matrix.

doubleCenterSymmetric

public static void doubleCenterSymmetric(double[][] m)

Double-center the given matrix (only upper triangle is used). For improved numerical precision, we perform incremental updates to the mean values, instead of computing a large sum and then performing division.

Parameters:

m - Matrix to double-center.