de.lmu.ifi.dbs.elki.data.projection.random

Class RandomSubsetProjectionFamily

java.lang.Object

de.lmu.ifi.dbs.elki.data.projection.random.AbstractRandomProjectionFamily

de.lmu.ifi.dbs.elki.data.projection.random.RandomSubsetProjectionFamily

All Implemented Interfaces:

RandomProjectionFamily

@Reference(authors="L. Breiman",
           title="Bagging predictors",
           booktitle="Machine learning 24.2",
           url="https://doi.org/10.1007/BF00058655",
           bibkey="DBLP:journals/ml/Breiman96b")
 @Alias(value="de.lmu.ifi.dbs.elki.math.linearalgebra.randomprojections.RandomSubsetProjectionFamily")
public class RandomSubsetProjectionFamily
extends AbstractRandomProjectionFamily

Random projection family based on selecting random features.

The basic idea of using this for data mining should probably be attributed to L. Breiman, who used it to improve the performance of predictors in an ensemble.

Reference:

L. Breiman
Bagging predictors
Machine learning 24.2

Since:

0.6.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RandomSubsetProjectionFamily.Parameterizer Parameterization class.
static class	RandomSubsetProjectionFamily.SubsetProjection Random subset projection.

Nested classes/interfaces inherited from class de.lmu.ifi.dbs.elki.data.projection.random.AbstractRandomProjectionFamily

AbstractRandomProjectionFamily.MatrixProjection

Nested classes/interfaces inherited from interface de.lmu.ifi.dbs.elki.data.projection.random.RandomProjectionFamily

RandomProjectionFamily.Projection

Field Summary

Fields inherited from class de.lmu.ifi.dbs.elki.data.projection.random.AbstractRandomProjectionFamily

random

Constructor Summary

Constructors

Constructor and Description
RandomSubsetProjectionFamily(RandomFactory random) Constructor.

Method Summary

Modifier and Type	Method and Description
RandomProjectionFamily.Projection	generateProjection(int idim, int odim) Generate a projection matrix for the given dimensionalities.
static int[]	randomPermutation(int[] out, java.util.Random random) Perform a random permutation of the array, in-place.
private static int[]	sequence(int e) Generate the integer sequence 0 .. e-1 TODO: move to shared code.

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomSubsetProjectionFamily

public RandomSubsetProjectionFamily(RandomFactory random)

Constructor.

Parameters:

random - Random generator.

Method Detail

generateProjection

public RandomProjectionFamily.Projection generateProjection(int idim,
                                                            int odim)

Description copied from interface: RandomProjectionFamily

Generate a projection matrix for the given dimensionalities.

Parameters:

idim - Input Dimensionality

odim - Output Dimensionality

Returns:

Projection matrix

randomPermutation

public static int[] randomPermutation(int[] out,
                                      java.util.Random random)

Perform a random permutation of the array, in-place. Knuth / Fisher-Yates style shuffle TODO: move to shared code.

Parameters:

out - Existing output array

random - Random generator.

Returns:

Same array.

sequence

private static int[] sequence(int e)

Generate the integer sequence 0 .. e-1

TODO: move to shared code.

Parameters:

e - End (exclusive)

Returns:

End