/*
* MachineAccuracy.java
*
* Copyright (c) 2002-2015 Alexei Drummond, Andrew Rambaut and Marc Suchard
*
* This file is part of BEAST.
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership and licensing.
*
* BEAST 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
* of the License, or (at your option) any later version.
*
* BEAST 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 BEAST; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
package dr.math;
/**
* determines machine accuracy
*
* @version $Id: MachineAccuracy.java,v 1.4 2005/05/24 20:26:01 rambaut Exp $
*
* @author Korbinian Strimmer
* @author Alexei Drummond
*/
public class MachineAccuracy
{
//
// Public stuff
//
/** machine accuracy constant */
public static double EPSILON = 2.220446049250313E-16;
public static double SQRT_EPSILON = 1.4901161193847656E-8;
public static double SQRT_SQRT_EPSILON = 1.220703125E-4;
/** compute EPSILON from scratch */
public static double computeEpsilon()
{
double eps = 1.0;
while( eps + 1.0 != 1.0 )
{
eps /= 2.0;
}
eps *= 2.0;
return eps;
}
/**
* @return true if the relative difference between the two parameters
* is smaller than SQRT_EPSILON.
*/
public static boolean same(double a, double b) {
return Math.abs((a/b)-1.0) <= SQRT_EPSILON;
}
}