com.mockturtlesolutions.snifflib.linalg

Class LUFact

java.lang.Object

com.mockturtlesolutions.snifflib.linalg.LUFact

All Implemented Interfaces:

LUAlgorithm

public class LUFact
extends java.lang.Object
implements LUAlgorithm

A basic decorator class for various methods of LU matrix decomposition. Note: That if you wish to perform Z = X^(-1)*B you can do this by LUFact LU = new LUFact(X); DblMatrix Z = LU.solveSystem(B); Similarly, if you need to compute L'*B*L where L=X^(-1) you can do two steps of LU backsubstitution with transposition as in: LUFact LU = new LUFact(X.transpose()); DblMatrix Z = LU.solveSystem(B); Z = LU.solveSystem(Z.transpose()); Z = Z.transpose();

Constructor Summary

Constructors

Constructor and Description
LUFact(AbstractLUAlgorithm Alg) Default construction useful when the user wants to use a non-default algorithm.
LUFact(DblMatrix X) Construction using the default algorithm.

Method Summary

Methods

Modifier and Type	Method and Description
AbstractLUAlgorithm	getAlgorithm()
DblMatrix	getL() Get the lower triangular L of the LU decomposition.
int	getSwapFactor() Returns (-1)^S where S is the number or row interchanges.
DblMatrix	getU() Get the upper triangular matrix U of the LU decomposition.
boolean	isSingular() Return true if a singular condition is encountered during.
void	setAlgorithm(AbstractLUAlgorithm a)
DblMatrix	solveSystem(DblMatrix b) Solve a linear system (X*b = Y) returning the coeficients as a DblMatrix.

Methods inherited from class java.lang.Object

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

Constructor Detail

LUFact

public LUFact(AbstractLUAlgorithm Alg)

Default construction useful when the user wants to use a non-default algorithm.

LUFact

public LUFact(DblMatrix X)

Construction using the default algorithm.

Method Detail

getL

public DblMatrix getL()

Description copied from interface: LUAlgorithm

Get the lower triangular L of the LU decomposition.

Specified by:

getL in interface LUAlgorithm

getU

public DblMatrix getU()

Description copied from interface: LUAlgorithm

Get the upper triangular matrix U of the LU decomposition.

Specified by:

getU in interface LUAlgorithm

setAlgorithm

public void setAlgorithm(AbstractLUAlgorithm a)

getAlgorithm

public AbstractLUAlgorithm getAlgorithm()

isSingular

public boolean isSingular()

Description copied from interface: LUAlgorithm

Return true if a singular condition is encountered during.

Specified by:

isSingular in interface LUAlgorithm

solveSystem

public DblMatrix solveSystem(DblMatrix b)

Description copied from interface: LUAlgorithm

Solve a linear system (X*b = Y) returning the coeficients as a DblMatrix.

Specified by:

solveSystem in interface LUAlgorithm

getSwapFactor

public int getSwapFactor()

Returns (-1)^S where S is the number or row interchanges.