no.uib.cipr.matrix.SymmEVD Maven / Gradle / Ivy
/*
* Copyright (C) 2003-2006 Bjørn-Ove Heimsund
*
* This file is part of MTJ.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package no.uib.cipr.matrix;
/**
* Symmetric eigenvalue decomposition
*/
abstract class SymmEVD {
/**
* Size of the matrix
*/
final int n;
/**
* The eigenvalues
*/
final double[] w;
/**
* The eigenvectors stored columnwise
*/
final DenseMatrix Z;
/**
* Job to do
*/
final JobEig job;
/**
* Allocates storage for an eigenvalue computation
*
* @param n
* Size of the matrix
* @param vectors
* True to compute the eigenvectors, false for just the
* eigenvalues
*/
public SymmEVD(int n, boolean vectors) {
this.n = n;
w = new double[n];
job = vectors ? JobEig.All : JobEig.Eigenvalues;
if (vectors)
Z = new DenseMatrix(n, n);
else
Z = null;
}
/**
* Allocates storage for an eigenvalue computation. Includes eigenvectors
*
* @param n
* Size of the matrix
*/
public SymmEVD(int n) {
this(n, true);
}
/**
* Gets the eigenvalues (stored in ascending order)
*/
public double[] getEigenvalues() {
return w;
}
/**
* Gets the eigenvectors, if available
*/
public DenseMatrix getEigenvectors() {
return Z;
}
/**
* True if the eigenvectors have been computed
*/
public boolean hasEigenvectors() {
return Z != null;
}
}