ThinkPHP/Library/Org/Util/PHPExcel/Shared/JAMA/EigenvalueDecomposition.php

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<?php
/**
 *    @package JAMA
 *
 *    Class to obtain eigenvalues and eigenvectors of a real matrix.
 *
 *    If A is symmetric, then A = V*D*V' where the eigenvalue matrix D
 *    is diagonal and the eigenvector matrix V is orthogonal (i.e.
 *    A = V.times(D.times(V.transpose())) and V.times(V.transpose())
 *    equals the identity matrix).
 *
 *    If A is not symmetric, then the eigenvalue matrix D is block diagonal
 *    with the real eigenvalues in 1-by-1 blocks and any complex eigenvalues,
 *    lambda + i*mu, in 2-by-2 blocks, [lambda, mu; -mu, lambda].  The
 *    columns of V represent the eigenvectors in the sense that A*V = V*D,
 *    i.e. A.times(V) equals V.times(D).  The matrix V may be badly
 *    conditioned, or even singular, so the validity of the equation
 *    A = V*D*inverse(V) depends upon V.cond().
 *
 *    @author  Paul Meagher
 *    @license PHP v3.0
 *    @version 1.1
 */
class EigenvalueDecomposition
{
    /**
     *    Row and column dimension (square matrix).
     *    @var int
     */
    private $n;

    /**
     *    Internal symmetry flag.
     *    @var int
     */
    private $issymmetric;

    /**
     *    Arrays for internal storage of eigenvalues.
     *    @var array
     */
    private $d = array();
    private $e = array();

    /**
     *    Array for internal storage of eigenvectors.
     *    @var array
     */
    private $V = array();

    /**
    *    Array for internal storage of nonsymmetric Hessenberg form.
    *    @var array
    */
    private $H = array();

    /**
    *    Working storage for nonsymmetric algorithm.
    *    @var array
    */