/* Copyright (C) 2002 Univ. of Massachusetts Amherst, Computer Science Dept.
This file is part of "MALLET" (MAchine Learning for LanguagE Toolkit).
http://www.cs.umass.edu/~mccallum/mallet
This software is provided under the terms of the Common Public License,
version 1.0, as published by http://www.opensource.org. For further
information, see the file `LICENSE' included with this distribution. */
/**
@author Andrew McCallum <a href="mailto:mccallum@cs.umass.edu">mccallum@cs.umass.edu</a>
*/
package cc.mallet.fst.tests;
import junit.framework.*;
public class TestSumNegLogProb2 extends TestCase
{
public TestSumNegLogProb2 (String name)
{
super (name);
}
private double sumNegLogProb (double a, double b) {
return - Math.log (Math.exp(-a) + Math.exp(-b));
}
public void testSum (double a, double b)
{
double al = - Math.log (a);
double bl = - Math.log (b);
double abl = sumNegLogProb (al, bl);
double ab = Math.exp (-abl);
System.out.println (" " + a +" + "+ b +" = "+ab);
System.out.println (">" + al +" + "+ bl +" = "+abl);
assertTrue (Math.abs (ab - (a+b)) < 0.001);
}
public void testTwo ()
{
testSum (.5, .5);
testSum (.9, .1);
testSum (.99, .01);
testSum (.99999, .00001);
testSum (.00001, 0.00001);
testSum (.00000001, 0.00001);
testSum (.0000000000001, 0.00001);
}
public static Test suite ()
{
return new TestSuite (TestSumNegLogProb2.class);
}
public static void main (String[] args)
{
junit.textui.TestRunner.run (suite());
}
}