org.ejml.alg.dense.decompose.qr

Class QRDecompositionHouseholderColumn_CD64

java.lang.Object

org.ejml.alg.dense.decompose.qr.QRDecompositionHouseholderColumn_CD64

All Implemented Interfaces:

DecompositionInterface<CDenseMatrix64F>, QRDecomposition<CDenseMatrix64F>

public class QRDecompositionHouseholderColumn_CD64
extends java.lang.Object
implements QRDecomposition<CDenseMatrix64F>

Householder QR decomposition is rich in operations along the columns of the matrix. This can be taken advantage of by solving for the Q matrix in a column major format to reduce the number of CPU cache misses and the number of copies that are performed.

See Also:

QRDecompositionHouseholder_D64

Constructor Summary

Constructors

Constructor and Description
QRDecompositionHouseholderColumn_CD64()

Method Summary

Modifier and Type	Method and Description
boolean	decompose(CDenseMatrix64F A) To decompose the matrix 'A' it must have full rank.
double[]	getGammas()
CDenseMatrix64F	getQ(CDenseMatrix64F Q, boolean compact) Computes the Q matrix from the imformation stored in the QR matrix.
double[][]	getQR() Returns the combined QR matrix in a 2D array format that is column major.
CDenseMatrix64F	getR(CDenseMatrix64F R, boolean compact) Returns an upper triangular matrix which is the R in the QR decomposition.
boolean	inputModified() Is the input matrix to DecompositionInterface.decompose(org.ejml.data.Matrix) is modified during the decomposition process.
void	setExpectedMaxSize(int numRows, int numCols)

Methods inherited from class java.lang.Object

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

Constructor Detail

QRDecompositionHouseholderColumn_CD64

public QRDecompositionHouseholderColumn_CD64()

Method Detail

setExpectedMaxSize

public void setExpectedMaxSize(int numRows,
                               int numCols)

getQR

public double[][] getQR()

Returns the combined QR matrix in a 2D array format that is column major.

Returns:

The QR matrix in a 2D matrix column major format. [ column ][ row ]

getQ

public CDenseMatrix64F getQ(CDenseMatrix64F Q,
                            boolean compact)

Computes the Q matrix from the imformation stored in the QR matrix. This operation requires about 4(m²n-mn²+n³/3) flops.

Specified by:

getQ in interface QRDecomposition<CDenseMatrix64F>

Parameters:

Q - The orthogonal Q matrix.

compact - If true an m by n matrix is created, otherwise n by n.

Returns:

The Q matrix.

getR

public CDenseMatrix64F getR(CDenseMatrix64F R,
                            boolean compact)

Returns an upper triangular matrix which is the R in the QR decomposition. If compact then the input expected to be size = [min(rows,cols) , numCols] otherwise size = [numRows,numCols].

Specified by:

getR in interface QRDecomposition<CDenseMatrix64F>

Parameters:

R - Storage for upper triangular matrix.

compact - If true then a compact matrix is expected.

Returns:

The R matrix.

decompose

public boolean decompose(CDenseMatrix64F A)

To decompose the matrix 'A' it must have full rank. 'A' is a 'm' by 'n' matrix. It requires about 2n*m²-2m²/3 flops.

The matrix provided here can be of different dimension than the one specified in the constructor. It just has to be smaller than or equal to it.

Specified by:

decompose in interface DecompositionInterface<CDenseMatrix64F>

Parameters:

A - The matrix which is being decomposed. Modification is implementation dependent.

Returns:

Returns if it was able to decompose the matrix.

inputModified

public boolean inputModified()

Description copied from interface: DecompositionInterface

Is the input matrix to DecompositionInterface.decompose(org.ejml.data.Matrix) is modified during the decomposition process.

Specified by:

inputModified in interface DecompositionInterface<CDenseMatrix64F>

Returns:

true if the input matrix to decompose() is modified.

getGammas

public double[] getGammas()