org.esa.snap.core.util.math

Class LinEqSysSolver

java.lang.Object

org.esa.snap.core.util.math.LinEqSysSolver

public class LinEqSysSolver
extends Object

A gauss-based solver for linear equation systems.

Version:

$Revision$ $Date$

Constructor Summary

Constructors

Constructor and Description
LinEqSysSolver()

Method Summary

Modifier and Type	Method and Description
static boolean	gauss_debug(double[][] a, double[] c, double[] x, int n, double eps) Same as the gausss method, but prints extra debug information.
static boolean	gauss(double[][] a, double[] c, double[] x, int n, double eps) Solves a linear equation system using the gaussian algorithm.
static boolean	pivotize(double[][] a, double[] c, int k, int n, double eps) Rearranges the matrix a by swapping line k with a suitable pivot line k'.

Methods inherited from class java.lang.Object

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

Constructor Detail

LinEqSysSolver

public LinEqSysSolver()

Method Detail

gauss

public static boolean gauss(double[][] a,
                            double[] c,
                            double[] x,
                            int n,
                            double eps)
                     throws SingularMatrixException

Solves a linear equation system using the gaussian algorithm.

Parameters:

a - coefficient matrix [0..n-1][0..n-1] (left side of equation)

c - the constant vector [0..n-1] (right side of equation)

x - the result vector [0..n-1] (right side of equation)

n - number of coefficients

eps - the epsilon value, e.g. 1.0e-09

Throws:

SingularMatrixException - if the matrix a is singular

gauss_debug

public static boolean gauss_debug(double[][] a,
                                  double[] c,
                                  double[] x,
                                  int n,
                                  double eps)

Same as the gausss method, but prints extra debug information.

Parameters:

a - coefficient matrix [0..n-1][0..n-1] (left side of equation)

c - the constant vector [0..n-1] (right side of equation)

x - the result vector [0..n-1] (right side of equation)

n - number of coefficients

eps - the epsilon value, e.g. 1.0e-09

Throws:

SingularMatrixException - if the matrix a is singular

See Also:

gauss(double[][], double[], double[], int, double)

pivotize

public static boolean pivotize(double[][] a,
                               double[] c,
                               int k,
                               int n,
                               double eps)

Rearranges the matrix a by swapping line k with a suitable pivot line k'.

Parameters:

a - coefficient matrix [0..n-1][0..n-1] (left side of equation)

c - the constant vector [0..n-1] (right side of equation)

k - the current index of a diagonal element = current line and column

n - matrix size

eps - the epsilon value, e.g. 1.0e-09

Throws:

SingularMatrixException - if the matrix a is singular