org.carrot2.matrix.factorization
Class PartialSingularValueDecomposition

java.lang.Object
  org.carrot2.matrix.factorization.PartialSingularValueDecomposition

All Implemented Interfaces:

IMatrixFactorization

public class PartialSingularValueDecomposition
extends Object
implements IMatrixFactorization

Performs matrix factorization using the Singular Value Decomposition algorithm.

Field Summary

protected org.apache.mahout.math.matrix.DoubleMatrix2D	A Input matrix
protected static int	DEFAULT_K The default number of desired base vectors
protected int	k The desired number of base vectors
protected org.apache.mahout.math.matrix.DoubleMatrix2D	U Base vector result matrix
protected org.apache.mahout.math.matrix.DoubleMatrix2D	V Coefficient result matrix

Constructor Summary

PartialSingularValueDecomposition(org.apache.mahout.math.matrix.DoubleMatrix2D A)
Computes a partial SVD of a matrix.

Method Summary

void	compute() Computes the factorization.
int	getK() Returns the number of base vectors k .
double[]	getSingularValues() Returns singular values of the matrix.
org.apache.mahout.math.matrix.DoubleMatrix2D	getU() Returns the U matrix (base vectors matrix).
org.apache.mahout.math.matrix.DoubleMatrix2D	getV() Returns the V matrix (coefficient matrix)
void	setK(int k) Sets the number of base vectors k .
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.carrot2.matrix.factorization.IMatrixFactorization

getU, getV

Field Detail

k

protected int k

The desired number of base vectors

DEFAULT_K

protected static final int DEFAULT_K

The default number of desired base vectors

See Also:

Constant Field Values

A

protected org.apache.mahout.math.matrix.DoubleMatrix2D A

Input matrix

U

protected org.apache.mahout.math.matrix.DoubleMatrix2D U

Base vector result matrix

V

protected org.apache.mahout.math.matrix.DoubleMatrix2D V

Coefficient result matrix

Constructor Detail

PartialSingularValueDecomposition

public PartialSingularValueDecomposition(org.apache.mahout.math.matrix.DoubleMatrix2D A)

Computes a partial SVD of a matrix. Before accessing results, perform computations by calling the compute()method.

Parameters:

A - matrix to be factorized

Method Detail

compute

public void compute()

Computes the factorization.

toString

public String toString()

Overrides:

toString in class Object

getSingularValues

public double[] getSingularValues()

Returns singular values of the matrix.

setK

public void setK(int k)

Sets the number of base vectors k .

Parameters:

k - the number of base vectors

getK

public int getK()

Returns the number of base vectors k .

getU

public org.apache.mahout.math.matrix.DoubleMatrix2D getU()

Description copied from interface: IMatrixFactorization

Returns the U matrix (base vectors matrix).

Specified by:

getU in interface IMatrixFactorization

Returns:

U matrix

getV

public org.apache.mahout.math.matrix.DoubleMatrix2D getV()

Description copied from interface: IMatrixFactorization

Returns the V matrix (coefficient matrix)

Specified by:

getV in interface IMatrixFactorization

Returns:

V matrix