MathUtil.java

/* ==========================================
 * JGraphT : a free Java graph-theory library
 * ==========================================
 *
 * Project Info:  http://jgrapht.sourceforge.net/
 * Project Creator:  Barak Naveh (http://sourceforge.net/users/barak_naveh)
 *
 * (C) Copyright 2003-2008, by Barak Naveh and Contributors.
 *
 * 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.
 */
/* -----------------
 * MathUtil.java
 * -----------------
 * (C) Copyright 2005-2008, by Assaf Lehr and Contributors.
 *
 * Original Author:  Assaf Lehr
 * Contributor(s):   -
 *
 * $Id: MathUtil.java 645 2008-09-30 19:44:48Z perfecthash $
 *
 * Changes
 * -------
 */
package edu.nd.nina.util;

/**
 * Math Utilities. Currently contains the following:
 * <li>factorial(int N) - caclulate the factorial of N (aka N!)
 *
 * @author Assaf
 * @since May 30, 2005
 */
public class MathUtil
{
    //~ Methods ----------------------------------------------------------------
    public static long factorial(int N)
    {
        long multi = 1;
        for (int i = 1; i <= N; i++) {
            multi = multi * i;
		}
		return multi;
	}

	/**
	 * Numbers that are closer than this are considered equal by almostEquals.
	 */
	public static double EPSILON = 0.000001;

	public static boolean almostEquals(double d1, double d2) {
		return almostEquals(d1, d2, EPSILON);
	}

	public static boolean almostEquals(double d1, double d2, double epsilon) {
		return Math.abs(d1 - d2) < epsilon;
	}

	public static boolean almostEquals(double[] d1, double[] d2, double eps) {
		for (int i = 0; i < d1.length; i++) {
			double v1 = d1[i];
			double v2 = d2[i];
			if (!almostEquals(v1, v2, eps))
				return false;
		}
		return true;
	}
	
	
}

// End MathUtil.java