bijnum
Class BIJJacobi

java.lang.Object
  |
  +--bijnum.BIJJacobi

public class BIJJacobi

extends java.lang.Object

This class implements the jacobi function as a Java class. Redesigned to be faster, for float. Internal calculations are still double though. From Press et al., 2nd ed., Numerical Solutions in C.

See Also:

for the original sources which I kept to be sure because they worked. Copyright (c) 1999-2003, Michael Abramoff. All rights reserved.

Field Summary

float[][]	a The matrix of which you want to compute E.
protected boolean	doFeedback Whether to show a showProgress() in ImageJ only.
float[]	eigenvalues
float[][]	eigenvectors
protected int	n
protected int	nrot
protected int	sweeps
protected static float	UNDERFLOW_LIMIT

Constructor Summary

BIJJacobi(float[][] m)
Create new instance to compute eigenvectors, eigenvalues.

BIJJacobi(float[][] m, boolean doFeedback)
Create new instance to compute eigenvectors, eigenvalues.

Method Summary

void	compute() Compute all eigenvalues and eigenvectors of a real symmetric matrix a[N][N].
int	nrot()
protected void	rotate(float[][] a, int i, int j, int k, int l, double s, double tau) Rotate, used to be a macro in C sources.
void	sort() Sort the eigenvalues/eigenvectors on the basis of the eigenvalues, largest first.
int	sweeps()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

a

public float[][] a

The matrix of which you want to compute E.

eigenvectors

public float[][] eigenvectors

eigenvalues

public float[] eigenvalues

doFeedback

protected boolean doFeedback

Whether to show a showProgress() in ImageJ only.

n

protected int n

nrot

protected int nrot

sweeps

protected int sweeps

UNDERFLOW_LIMIT

protected static final float UNDERFLOW_LIMIT

Constructor Detail

BIJJacobi

public BIJJacobi(float[][] m,
                 boolean doFeedback)
          throws BIJException

Create new instance to compute eigenvectors, eigenvalues.

Parameters:

m - a real, symmetric matrix of nxn.

doFeedback, - whether a progress routine should be called after each sweep (only for user interaction).

BIJJacobi

public BIJJacobi(float[][] m)
          throws BIJException

Create new instance to compute eigenvectors, eigenvalues.

Parameters:

m - a real symmetric matrix of NxN.

Method Detail

compute

public void compute()

Compute all eigenvalues and eigenvectors of a real symmetric matrix a[N][N]. Will destroy a!. The eigenvalues/eigenvectors can be obtained from the corresponding public variables. From: Press et al., Numerical Recipes in C, 2nd ed., pp 467-

sort

public void sort()

Sort the eigenvalues/eigenvectors on the basis of the eigenvalues, largest first. Straight insertion method.

rotate

protected void rotate(float[][] a,
                      int i,
                      int j,
                      int k,
                      int l,
                      double s,
                      double tau)

Rotate, used to be a macro in C sources. The comment below applies to C source, but I kept it in for historical reasons. Note: Numerical Recipes source uses a #define for function "rotate". On some compilers this may result in a nonfunctional jacobi (took me 3 days to find this out). So please keep "rotate" as a function!

nrot

public int nrot()

sweeps

public int sweeps()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object