eigenvaluedecomposition.java

一个关于java 的常用工具包

package org.jutil.math.matrix;

/**
 * A class of eigenvalue decompositions of a matrix.
 *
 * @path    $Source: /cvsroot/org-jutil/jutil.org/src/org/jutil/math/matrix/EigenvalueDecomposition.java,v $
 * @version $Revision: 1.4 $
 * @date    $Date: 2002/07/02 14:27:31 $
 * @state   $State: Exp $
 * @author  Marko van Dooren
 * @release $Name:  $
 */
public interface EigenvalueDecomposition {

	/* The revision of this class */
	public final static String CVS_REVISION ="$Revision: 1.4 $";

	/**
	 * Return the eigenvalue matrix of this EigenvalueDecomposition.
	 */
 /*@
	 @ public behavior
	 @
	 @ post \result != null;
	 @ post \result.isDiagonal();
   @ post \result.getNbRows() == getNbEigenvalues();
   @ post \result.isSquare();
	 @ post (\forall int i; i>=1 && i <= getNbEigenvalues();
	 @        \result.elementAt(i,i) == getEigenvalue(i));
	 @*/
	public Matrix lambda();

	/**
	 * Return the eigenvectors.
	 */
 /*@
	 @ public behavior
	 @
	 @ post \result != null;
	 @*/
  public Matrix getEigenvectors();

  /**
   * Return the eigenvalues.
	 */
 /*@
	 @ public behavior
	 @
	 @ post \result != null;
	 @ post (\forall int i; i>=1 && i<=\result.size();
	 @        \result.elementAt(i) != 0);
	 @*/
  public Column getEigenvalues();

	/**
	 * Return the index'th eigenvector.
	 *
	 * @param index
	 *        The index of the requested eigenvector.
	 */
 /*@
	 @ public behavior
	 @
	 @ pre index >= 1;
	 @ pre index <= getNbEigenvalues();
	 @
	 @ post \result.equals(getEigenvectors().getColumn(index));
	 @*/
  public Column getEigenvector(int index);

	/**
	 * Return the index'th eigenvalue.
	 *
	 * @param index
	 *        The index of the requested eigenvalue.
	 */
 /*@
	 @ public behavior
	 @
	 @ pre index >= 1;
	 @ pre index <= getNbEigenvalues();
	 @
	 @ post \result == getEigenvalues().elementAt(index);
	 @*/
  public double getEigenvalue(int index);

  /**
	 * Return the number of eigenvalues.
	 */
 /*@
	 @ public behavior
	 @
	 @ post \result == getEigenvalues().size();
	 @*/
	public int getNbEigenvalues();
}
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behalf of the JUTIL.ORG Project. The copyright is dated by the dates 
after the "@date" tags above. All rights reserved.
This software is published under the terms of the JUTIL.ORG Software
License version 1.1 or later, a copy of which has been included with
this distribution in the LICENSE file, which can also be found at
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License for more details.
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