Package org.ejml.sparse.csc.decomposition.qr

Class QrLeftLookingDecomposition_DSCC

java.lang.Object

org.ejml.sparse.csc.decomposition.qr.QrLeftLookingDecomposition_DSCC

All Implemented Interfaces:

DecompositionInterface<DMatrixSparseCSC>, DecompositionSparseInterface<DMatrixSparseCSC>, QRDecomposition<DMatrixSparseCSC>, QRSparseDecomposition<DMatrixSparseCSC>

public class QrLeftLookingDecomposition_DSCC
extends Object
implements QRSparseDecomposition<DMatrixSparseCSC>

Left-looking QR decomposition algorithm for sparse matrices. A=Q*R

NOTE: See qr_left on page 71 and cs_qr() in csparse

Constructor Summary

Constructors

Constructor	Description
QrLeftLookingDecomposition_DSCC(@Nullable ComputePermutation<DMatrixSparseCSC> permutation)

Method Summary

Modifier and Type	Method	Description
boolean	decompose(DMatrixSparseCSC A)	Computes the decomposition of the input matrix.
double[]	getBeta()
double	getBeta(int index)
int[]	getFillPermutation()
IGrowArray	getGwork()
DGrowArray	getGx()
DMatrixSparseCSC	getQ(@Nullable DMatrixSparseCSC Q, boolean compact)	Returns the Q matrix from the decomposition.
DMatrixSparseCSC	getR()
DMatrixSparseCSC	getR(@Nullable DMatrixSparseCSC R, boolean compact)	Returns the R matrix from the decomposition.
QrStructuralCounts_DSCC	getStructure()
DMatrixSparseCSC	getV()
boolean	inputModified()	Checks if the input matrix to DecompositionInterface.decompose(org.ejml.data.Matrix) is modified during the decomposition process.
boolean	isFillPermutated()
boolean	isSingular()
boolean	isStructureLocked()	Checks to see if the structure is locked.
void	setStructureLocked(boolean locked)	Save results from structural analysis step.

Methods inherited from class java.lang.Object

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

Constructor Details

QrLeftLookingDecomposition_DSCC

public QrLeftLookingDecomposition_DSCC(@Nullable
 @Nullable ComputePermutation<DMatrixSparseCSC> permutation)

Method Details

decompose

public boolean decompose(DMatrixSparseCSC A)

Description copied from interface: DecompositionInterface

Computes the decomposition of the input matrix. Depending on the implementation the input matrix might be stored internally or modified. If it is modified then the function DecompositionInterface.inputModified() will return true and the matrix should not be modified until the decomposition is no longer needed.

Specified by:

decompose in interface DecompositionInterface<DMatrixSparseCSC>

Parameters:

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

Returns:

Returns if it was able to decompose the matrix.

getQ

public DMatrixSparseCSC getQ(@Nullable
 @Nullable DMatrixSparseCSC Q,
 boolean compact)

Description copied from interface: QRDecomposition

Returns the Q matrix from the decomposition. Should only be called after DecompositionInterface.decompose(org.ejml.data.Matrix) has been called.

Specified by:

getQ in interface QRDecomposition<DMatrixSparseCSC>

Parameters:

Q - (Input) Storage for Q. Reshaped to correct size automatically. If null a new matrix is created.

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

Returns:

The Q matrix.

getR

public DMatrixSparseCSC getR(@Nullable
 @Nullable DMatrixSparseCSC R,
 boolean compact)

Description copied from interface: QRDecomposition

Returns the R matrix from the decomposition. Should only be called after DecompositionInterface.decompose(org.ejml.data.Matrix) has been.

If setZeros is true then an n × m matrix is required and all the elements are set. If setZeros is false then the matrix must be at least m × m and only the upper triangular elements are set.

Specified by:

getR in interface QRDecomposition<DMatrixSparseCSC>

Parameters:

R - (Input) Storage for R. Reshaped to correct size automatically. If null a new matrix is created.

compact - If true only the upper triangular elements are set

Returns:

The R matrix.

inputModified

public boolean inputModified()

Description copied from interface: DecompositionInterface

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

Specified by:

inputModified in interface DecompositionInterface<DMatrixSparseCSC>

Returns:

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

getGwork

public IGrowArray getGwork()

getGx

public DGrowArray getGx()

getStructure

public QrStructuralCounts_DSCC getStructure()

getV

public DMatrixSparseCSC getV()

getR

public DMatrixSparseCSC getR()

getBeta

public double[] getBeta()

getBeta

public double getBeta(int index)

getFillPermutation

public int[] getFillPermutation()

isFillPermutated

public boolean isFillPermutated()

isSingular

public boolean isSingular()

setStructureLocked

public void setStructureLocked(boolean locked)

Description copied from interface: DecompositionSparseInterface

Save results from structural analysis step. This can reduce computations if a matrix with the exactly same non-zero pattern is decomposed in the future. If a matrix has yet to be processed then the structure of the next matrix is saved. If a matrix has already been processed then the structure of the most recently processed matrix will be saved.

Specified by:

setStructureLocked in interface DecompositionSparseInterface<DMatrixSparseCSC>

isStructureLocked

public boolean isStructureLocked()

Description copied from interface: DecompositionSparseInterface

Checks to see if the structure is locked.

Specified by:

isStructureLocked in interface DecompositionSparseInterface<DMatrixSparseCSC>

Returns:

true if locked or false if not locked.