org.ejml.alg.dense.decomposition.eig.symm

Class SymmetricQREigenHelper

java.lang.Object

org.ejml.alg.dense.decomposition.eig.symm.SymmetricQREigenHelper

public class SymmetricQREigenHelper
extends java.lang.Object

A helper class for the symmetric matrix implicit QR algorithm for eigenvalue decomposition. Performs most of the basic operations needed to extract eigenvalues and eigenvectors.

Constructor Summary

Constructors

Constructor and Description
SymmetricQREigenHelper()

Method Summary

Modifier and Type	Method and Description
double	computeShift()
double	computeWilkinsonShift()
double[]	copyDiag(double[] ret)
double[]	copyEigenvalues(double[] ret)
double[]	copyOff(double[] ret)
void	exceptionalShift() Perform a shift in a random direction that is of the same magnitude as the elements in the matrix.
int	getMatrixSize()
void	incrementSteps()
void	init(double[] diag, double[] off, int numCols) Sets up and declares internal data structures.
boolean	nextSplit() Tells it to process the submatrix at the next split.
void	printMatrix()
void	reset(int N) Sets the size of the matrix being decomposed, declares new memory if needed, and sets all helper functions to their initial value.
void	resetSteps()
void	setQ(DenseMatrix64F q)
void	setSubmatrix(int x1, int x2) Sets which submatrix is being processed.
double[]	swapDiag(double[] diag) Exchanges the internal array of the diagonal elements for the provided one.
double[]	swapOff(double[] off) Exchanges the internal array of the off diagonal elements for the provided one.

Methods inherited from class java.lang.Object

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

Constructor Detail

SymmetricQREigenHelper

public SymmetricQREigenHelper()

Method Detail

printMatrix

public void printMatrix()

setQ

public void setQ(DenseMatrix64F q)

incrementSteps

public void incrementSteps()

init

public void init(double[] diag,
                 double[] off,
                 int numCols)

Sets up and declares internal data structures.

Parameters:

diag - Diagonal elements from tridiagonal matrix. Modified.

off - Off diagonal elements from tridiagonal matrix. Modified.

numCols - number of columns (and rows) in the matrix.

swapDiag

public double[] swapDiag(double[] diag)

Exchanges the internal array of the diagonal elements for the provided one.

swapOff

public double[] swapOff(double[] off)

Exchanges the internal array of the off diagonal elements for the provided one.

reset

public void reset(int N)

Sets the size of the matrix being decomposed, declares new memory if needed, and sets all helper functions to their initial value.

copyDiag

public double[] copyDiag(double[] ret)

copyOff

public double[] copyOff(double[] ret)

copyEigenvalues

public double[] copyEigenvalues(double[] ret)

setSubmatrix

public void setSubmatrix(int x1,
                         int x2)

Sets which submatrix is being processed.

Parameters:

x1 - Lower bound, inclusive.

x2 - Upper bound, inclusive.

exceptionalShift

public void exceptionalShift()

Perform a shift in a random direction that is of the same magnitude as the elements in the matrix.

nextSplit

public boolean nextSplit()

Tells it to process the submatrix at the next split. Should be called after the current submatrix has been processed.

computeShift

public double computeShift()

computeWilkinsonShift

public double computeWilkinsonShift()

getMatrixSize

public int getMatrixSize()

resetSteps

public void resetSteps()