Common
Class MatrixInversion

java.lang.Object
  Common.MatrixInversion

public class MatrixInversion
extends java.lang.Object

This class is responsible for inverting a matrix for solving a linear equation Ax = b .
This is needed for finding the physical coordinates from screen coordinates (for example, in showing mouse coordinates on the viewer in real time).
Here we need to solve the following equation for X_physical
X_physical * Transformation_Matrix = X_screen
We know the screen coordinates (current mouse coordinates), but need the corresponding physical coodinates.
This is a singleton class.

Since:

1.0

Field Summary

private static double	EPSILON
private int[]	mEqnOrder Because of partial pivoting, equations may be reordered.
private static MatrixInversion	mInstance Single instance of this class.
private float[]	mLUDecomposedMatrix LU decomposition of matrix (4X4).
private float[]	mMultipliers

Constructor Summary

private

MatrixInversion() Class constructor.

Method Summary

private void	BackSubstitutor(float[] A, float[] b)
private void	ForwardSubstitutor(float[] A, float[] b)
static MatrixInversion	Instance() Get the singleton instance of the class.
private boolean	LUDecomposer(float[] A, float[] b)
private void	ReorderB(float[] b)
boolean	SolveEqn(float[] A, float[] b, boolean decomposed)
private boolean	Solver(float[] A, float[] b, boolean decomposed) Solve the equation Ax = b, putting the answer in b.

Methods inherited from class java.lang.Object

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

Field Detail

mLUDecomposedMatrix

private float[] mLUDecomposedMatrix

LU decomposition of matrix (4X4).

mEqnOrder

private int[] mEqnOrder

Because of partial pivoting, equations may be reordered.

mMultipliers

private float[] mMultipliers

EPSILON

private static final double EPSILON

See Also:

Constant Field Values

mInstance

private static MatrixInversion mInstance

Single instance of this class.

Constructor Detail

MatrixInversion

private MatrixInversion()

Class constructor.

Method Detail

Instance

public static MatrixInversion Instance()

Get the singleton instance of the class.

Returns:

MatrixInversion instance

See Also:

mLUDecomposedMatrix

LUDecomposer

private boolean LUDecomposer(float[] A,
                             float[] b)

ReorderB

private void ReorderB(float[] b)

ForwardSubstitutor

private void ForwardSubstitutor(float[] A,
                                float[] b)

BackSubstitutor

private void BackSubstitutor(float[] A,
                             float[] b)

Solver

private boolean Solver(float[] A,
                       float[] b,
                       boolean decomposed)

Solve the equation Ax = b, putting the answer in b.

Parameters:

A - A 16 element (4X4) array containing coefficient matrix.

b - RHS (4 element array). the array can get reordered (the inversion process involves partial pivoting). The array is overwritten with the result.

decomposed - boolean flag: true if A has been LU decomposed by an earlier invocation to this function with this flag false. false if this matrix is being sumbitted for the first time.

Returns:

true if inversion went OK, false if singular (or near singular matrix encountered).

SolveEqn

public boolean SolveEqn(float[] A,
                        float[] b,
                        boolean decomposed)