org.ejml.alg.dense.linsol.lu

Class LinearSolverLuBase_D64

java.lang.Object

org.ejml.alg.dense.linsol.LinearSolverAbstract_D64

org.ejml.alg.dense.linsol.lu.LinearSolverLuBase_D64

All Implemented Interfaces:

LinearSolver<DenseMatrix64F>

Direct Known Subclasses:

LinearSolverLu_D64, LinearSolverLuKJI_D64

public abstract class LinearSolverLuBase_D64
extends LinearSolverAbstract_D64

Constructor Summary

Constructors

Constructor and Description
LinearSolverLuBase_D64(LUDecompositionBase_D64 decomp)

Method Summary

Modifier and Type	Method and Description
LUDecompositionBase_D64	getDecomposition() If a decomposition class was used internally then this will return that class.
void	improveSol(DenseMatrix64F b, DenseMatrix64F x) This attempts to improve upon the solution generated by account for numerical imprecisions.
void	invert(DenseMatrix64F A_inv) Computes the inverse of of the 'A' matrix passed into LinearSolver.setA(org.ejml.data.Matrix) and writes the results to the provided matrix.
boolean	modifiesA() Returns true if the passed in matrix to LinearSolver.setA(org.ejml.data.Matrix) is modified.
boolean	modifiesB() Returns true if the passed in 'B' matrix to LinearSolver.solve(org.ejml.data.Matrix, org.ejml.data.Matrix) is modified.
double	quality() Returns a very quick to compute measure of how singular the system is.
boolean	setA(DenseMatrix64F A) Specifies the A matrix in the linear equation.

Methods inherited from class org.ejml.alg.dense.linsol.LinearSolverAbstract_D64

getA

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.ejml.interfaces.linsol.LinearSolver

solve

Constructor Detail

LinearSolverLuBase_D64

public LinearSolverLuBase_D64(LUDecompositionBase_D64 decomp)

Method Detail

setA

public boolean setA(DenseMatrix64F A)

Description copied from interface: LinearSolver

Specifies the A matrix in the linear equation. A reference might be saved and it might also be modified depending on the implementation. If it is modified then LinearSolver.modifiesA() will return true.

If this value returns true that does not guarantee a valid solution was generated. This is because some decompositions don't detect singular matrices.

Parameters:

A - The 'A' matrix in the linear equation. Might be modified or save the reference.

Returns:

true if it can be processed.

quality

public double quality()

Description copied from interface: LinearSolver

Returns a very quick to compute measure of how singular the system is. This measure will be invariant to the scale of the matrix and always be positive, with larger values indicating it is less singular. If not supported by the solver then the runtime exception IllegalArgumentException is thrown. This is NOT the matrix's condition.

How this function is implemented is not specified. One possible implementation is the following: In many decompositions a triangular matrix is extracted. The determinant of a triangular matrix is easily computed and once normalized to be scale invariant and its absolute value taken it will provide functionality described above.

Returns:

The quality of the linear system.

invert

public void invert(DenseMatrix64F A_inv)

Description copied from interface: LinearSolver

Computes the inverse of of the 'A' matrix passed into LinearSolver.setA(org.ejml.data.Matrix) and writes the results to the provided matrix. If 'A_inv' needs to be different from 'A' is implementation dependent.

Specified by:

invert in interface LinearSolver<DenseMatrix64F>

Overrides:

invert in class LinearSolverAbstract_D64

Parameters:

A_inv - Where the inverted matrix saved. Modified.

improveSol

public void improveSol(DenseMatrix64F b,
                       DenseMatrix64F x)

This attempts to improve upon the solution generated by account for numerical imprecisions. See numerical recipes for more information. It is assumed that solve has already been run on 'b' and 'x' at least once.

Parameters:

b - A matrix. Not modified.

x - A matrix. Modified.

modifiesA

public boolean modifiesA()

Description copied from interface: LinearSolver

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

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(org.ejml.data.Matrix, org.ejml.data.Matrix) is modified.

Returns:

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

getDecomposition

public LUDecompositionBase_D64 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.

Returns:

Internal decomposition class. If there is none then null.