Package org.ejml.dense.block.linsol.qr

Class QrHouseHolderSolver_DDRB

java.lang.Object

org.ejml.dense.block.linsol.qr.QrHouseHolderSolver_DDRB

All Implemented Interfaces:

LinearSolver<DMatrixRBlock,DMatrixRBlock>, LinearSolverDense<DMatrixRBlock>

public class QrHouseHolderSolver_DDRB
extends Object
implements LinearSolverDense<DMatrixRBlock>

A solver for QRDecompositionHouseholder_DDRB. Systems are solved for using the standard QR decomposition method, sketched below.

A = Q*R
A*x = b
Q*R*x = b
R*x = y = Q^Tb
x = R^-1y

Where A is the m by n matrix being decomposed. Q is an orthogonal matrix. R is upper triangular matrix.

Field Summary

Fields

Modifier and Type	Field	Description
protected QRDecompositionHouseholder_DDRB	decomposer
protected DMatrixRBlock	QR

Constructor Summary

Constructors

Constructor	Description
QrHouseHolderSolver_DDRB()

Method Summary

Modifier and Type	Method	Description
QRDecomposition<DMatrixRBlock>	getDecomposition()	If a decomposition class was used internally then this will return that class.
void	invert(DMatrixRBlock A_inv)	Invert by solving for against an identity matrix.
boolean	modifiesA()	Returns true if the passed in matrix to LinearSolver.setA(Matrix) is modified.
boolean	modifiesB()	Returns true if the passed in 'B' matrix to LinearSolver.solve(Matrix, Matrix) is modified.
double	quality()	Computes the quality using diagonal elements the triangular R matrix in the QR decomposition.
boolean	setA(DMatrixRBlock A)	Computes the QR decomposition of A and store the results in A.
void	solve(DMatrixRBlock B, DMatrixRBlock X)	Solves for X in the linear system, A*X=B.

Methods inherited from class java.lang.Object

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

Field Details

decomposer

protected QRDecompositionHouseholder_DDRB decomposer

QR

protected DMatrixRBlock QR

Constructor Details

QrHouseHolderSolver_DDRB

public QrHouseHolderSolver_DDRB()

Method Details

setA

public boolean setA(DMatrixRBlock A)

Computes the QR decomposition of A and store the results in A.

Specified by:

setA in interface LinearSolver<DMatrixRBlock,DMatrixRBlock>

Parameters:

A - The A matrix in the linear equation. Modified. Reference saved.

Returns:

true if the decomposition was successful.

quality

public double quality()

Computes the quality using diagonal elements the triangular R matrix in the QR decomposition.

Specified by:

quality in interface LinearSolver<DMatrixRBlock,DMatrixRBlock>

Returns:

Solutions quality.

solve

public void solve(DMatrixRBlock B,
 DMatrixRBlock X)

Description copied from interface: LinearSolver

Solves for X in the linear system, A*X=B.

In some implementations 'B' and 'X' can be the same instance of a variable. Call LinearSolver.modifiesB() to determine if 'B' is modified.

Specified by:

solve in interface LinearSolver<DMatrixRBlock,DMatrixRBlock>

Parameters:

B - A matrix ℜ ^{m × p}. Might be modified.

X - A matrix ℜ ^{n × p}, where the solution is written to. Modified.

invert

public void invert(DMatrixRBlock A_inv)

Invert by solving for against an identity matrix.

Specified by:

invert in interface LinearSolverDense<DMatrixRBlock>

Parameters:

A_inv - Where the inverted matrix saved. Modified.

modifiesA

public boolean modifiesA()

Description copied from interface: LinearSolver

Returns true if the passed in matrix to LinearSolver.setA(Matrix) is modified.

Specified by:

modifiesA in interface LinearSolver<DMatrixRBlock,DMatrixRBlock>

Returns:

true if A is modified in setA().

modifiesB

public boolean modifiesB()

Description copied from interface: LinearSolver

Returns true if the passed in 'B' matrix to LinearSolver.solve(Matrix, Matrix) is modified.

Specified by:

modifiesB in interface LinearSolver<DMatrixRBlock,DMatrixRBlock>

Returns:

true if B is modified in solve(B,X).

getDecomposition

public QRDecomposition<DMatrixRBlock> getDecomposition()

Description copied from interface: LinearSolver

If a decomposition class was used internally then this will return that class. Most linear solvers decompose the input matrix into a more simplistic form. However some solutions do not require decomposition, e.g. inverse by minor.

Specified by:

getDecomposition in interface LinearSolver<DMatrixRBlock,DMatrixRBlock>

Returns:

Internal decomposition class. If there is none then null.