com.mockturtlesolutions.snifflib.linalg

Class NRLUAlgorithm

java.lang.Object

com.mockturtlesolutions.snifflib.linalg.AbstractLUAlgorithm

com.mockturtlesolutions.snifflib.linalg.NRLUAlgorithm

All Implemented Interfaces:

LUAlgorithm

public class NRLUAlgorithm
extends AbstractLUAlgorithm

This LU algorithm closely follows the one given in Numerical Recipes in Fortran by Press et al. 1992

Constructor Summary

Constructors

Constructor and Description
NRLUAlgorithm(DblMatrix X)

Method Summary

Methods

Modifier and Type	Method and Description
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.
DblMatrix	solveSystem(DblMatrix b) Solves the set of n linear equations A*X = B.

Methods inherited from class java.lang.Object

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

Constructor Detail

NRLUAlgorithm

public NRLUAlgorithm(DblMatrix X)

Method Detail

getSwapFactor

public int getSwapFactor()

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

Specified by:

getSwapFactor in class AbstractLUAlgorithm

solveSystem

public DblMatrix solveSystem(DblMatrix b)

Solves the set of n linear equations A*X = B. Generally used in combination with DblMatrix.ludcmp to solve linear system in the following way: X = U\(L\B) DblMatrix[] LUINFO = DblMatrix.ludcmp(A); DblMatrix X = DblMatrix.lubksb(LUINFO,B); By separating the ludcmp and lubksb the same decomposition can be used over and over for different B. Note lubksb only does backsubstitutions for the non-zero B. Follows the code of Press et al in Numerical Receipes in Fortran The Art of Scientific Computing p38-39.

Specified by:

solveSystem in interface LUAlgorithm

Specified by:

solveSystem in class AbstractLUAlgorithm

isSingular

public boolean isSingular()

Description copied from class: AbstractLUAlgorithm

Return true if a singular condition is encountered during.

Specified by:

isSingular in interface LUAlgorithm

Specified by:

isSingular in class AbstractLUAlgorithm

getL

public DblMatrix getL()

Description copied from interface: LUAlgorithm

Get the lower triangular L of the LU decomposition.

Specified by:

getL in interface LUAlgorithm

Specified by:

getL in class AbstractLUAlgorithm

getU

public DblMatrix getU()

Description copied from class: AbstractLUAlgorithm

Get the upper triangular matrix U of the LU decomposition.

Specified by:

getU in interface LUAlgorithm

Specified by:

getU in class AbstractLUAlgorithm