de.lmu.ifi.dbs.elki.math.linearalgebra.randomprojections

Class SimplifiedRandomHyperplaneProjectionFamily.SignedProjection

java.lang.Object

de.lmu.ifi.dbs.elki.math.linearalgebra.randomprojections.SimplifiedRandomHyperplaneProjectionFamily.SignedProjection

All Implemented Interfaces:

RandomProjectionFamily.Projection

Enclosing class:

SimplifiedRandomHyperplaneProjectionFamily

private static class SimplifiedRandomHyperplaneProjectionFamily.SignedProjection
extends Object
implements RandomProjectionFamily.Projection

Fast projection class, using booleans to represent +-1 matrix entries. Optimized for sparse multiplications, thus we are using a column-row layout.

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
private double[]	buf Shared buffer to use during projections.
private int	k Output dimensionality
(package private) boolean[][]	mat Projection matrix.

Constructor Summary

Constructors

Constructor and Description
SimplifiedRandomHyperplaneProjectionFamily.SignedProjection(int dim, int k, Random random) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
int	getOutputDimensionality() Get the output dimensionality.
double[]	project(NumberVector in) Project a single vector.
double[]	project(NumberVector vec, double[] ret) Project a single vector, into the given buffer.
private double[]	projectDense(NumberVector in, double[] ret) Slower version, for dense multiplication.

Methods inherited from class java.lang.Object

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

Field Detail

mat

boolean[][] mat

Projection matrix.

k

private int k

Output dimensionality

buf

private double[] buf

Shared buffer to use during projections.

Constructor Detail

SimplifiedRandomHyperplaneProjectionFamily.SignedProjection

public SimplifiedRandomHyperplaneProjectionFamily.SignedProjection(int dim,
                                                           int k,
                                                           Random random)

Constructor.

Parameters:

dim - Input dimensionality

k - Output dimensionality

random - Random generator

Method Detail

project

public double[] project(NumberVector in)

Description copied from interface: RandomProjectionFamily.Projection

Project a single vector.

Specified by:

project in interface RandomProjectionFamily.Projection

Parameters:

in - Input vector

Returns:

Projected vector

project

public double[] project(NumberVector vec,
               double[] ret)

Description copied from interface: RandomProjectionFamily.Projection

Project a single vector, into the given buffer.

Specified by:

project in interface RandomProjectionFamily.Projection

Parameters:

vec - Input vector

ret - Output buffer

Returns:

buffer

projectDense

private double[] projectDense(NumberVector in,
                    double[] ret)

Slower version, for dense multiplication.

Parameters:

in - Input vector

Returns:

Projected data.

getOutputDimensionality

public int getOutputDimensionality()

Description copied from interface: RandomProjectionFamily.Projection

Get the output dimensionality.

Specified by:

getOutputDimensionality in interface RandomProjectionFamily.Projection

Returns:

Output dimensionality