mikera.matrixx.decompose.impl.lu

Class AltLU

java.lang.Object

mikera.matrixx.decompose.impl.lu.AltLU

public class AltLU
extends Object

Contains common data structures and operations for LU decomposition algorithms.

Author:

Peter Abeles

Field Summary

Fields

Modifier and Type	Field and Description
protected double[]	dataLU
protected int[]	indx
protected Matrix	LU
protected int	m
protected int	maxWidth
protected int	n
protected int[]	pivot
protected double[]	vv

Constructor Summary

Constructors

Constructor and Description
AltLU()

Method Summary

Modifier and Type	Method and Description
LUPResult	_decompose(AMatrix a) This is a modified version of what was found in the JAMA package.
double[]	_getVV()
void	_solveVectorInternal(double[] vv) a specialized version of solve that avoid additional checks that are not needed.
static LUPResult	decompose(AMatrix A)
int[]	getIndx()
AMatrix	getLU()
int[]	getPivot()
boolean	isSingular() Determines if the decomposed matrix is singular.
double	quality() the quality is the absolute value of the product of each diagonal element divided by the magnitude of the largest diagonal element.

Methods inherited from class java.lang.Object

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

Field Detail

LU

protected Matrix LU

maxWidth

protected int maxWidth

m

protected int m

n

protected int n

dataLU

protected double[] dataLU

vv

protected double[] vv

indx

protected int[] indx

pivot

protected int[] pivot

Constructor Detail

AltLU

public AltLU()

Method Detail

decompose

public static LUPResult decompose(AMatrix A)

getLU

public AMatrix getLU()

getIndx

public int[] getIndx()

getPivot

public int[] getPivot()

quality

public double quality()

the quality is the absolute value of the product of each diagonal element divided by the magnitude of the largest diagonal element. If all diagonal elements are zero then zero is returned.

Returns:

_decompose

public LUPResult _decompose(AMatrix a)

This is a modified version of what was found in the JAMA package. The order that it performs its permutations in is the primary difference from NR

Parameters:

a - The matrix that is to be decomposed. Not modified.

Returns:

true If the matrix can be decomposed and false if it can not.

_solveVectorInternal

public void _solveVectorInternal(double[] vv)

a specialized version of solve that avoid additional checks that are not needed.

_getVV

public double[] _getVV()

isSingular

public boolean isSingular()

Determines if the decomposed matrix is singular. This function can return false and the matrix be almost singular, which is still bad.

Returns:

true if singular false otherwise.