Coverage Report - org.apache.commons.math.special.Erf

Classes in this File	Line Coverage	Branch Coverage	Complexity
Erf	67%	100%	1.5;1.5

1		/*
2		* Copyright 2004 The Apache Software Foundation.
3		*
4		* Licensed under the Apache License, Version 2.0 (the "License");
5		* you may not use this file except in compliance with the License.
6		* You may obtain a copy of the License at
7		*
8		* http://www.apache.org/licenses/LICENSE-2.0
9		*
10		* Unless required by applicable law or agreed to in writing, software
11		* distributed under the License is distributed on an "AS IS" BASIS,
12		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13		* See the License for the specific language governing permissions and
14		* limitations under the License.
15		*/
16		package org.apache.commons.math.special;
17
18		import java.io.Serializable;
19
20		import org.apache.commons.math.MathException;
21
22		/**
23		* This is a utility class that provides computation methods related to the
24		* error functions.
25		*
26		* @version $Revision$ $Date: 2005-02-26 05:11:52 -0800 (Sat, 26 Feb 2005) $
27		*/
28		public class Erf implements Serializable {
29
30		/**
31		* Default constructor. Prohibit instantiation.
32		*/
33		private Erf() {
34	0	super();
35	0	}
36
37		/**
38		* Returns the error function erf(x).
39		*
40		* The implementation of this method is based on:
41		* <ul>
42		* <li>
43		* <a href="http://mathworld.wolfram.com/Erf.html">
44		* Erf</a>, equation (3).</li>
45		* </ul>
46		*
47		* @param x the value.
48		* @return the error function erf(x)
49		* @throws MathException if the algorithm fails to converge.
50		*/
51		public static double erf(double x) throws MathException {
52	470	double ret = Gamma.regularizedGammaP(0.5, x * x, 1.0e-15, 10000);
53	470	if (x < 0) {
54	198	ret = -ret;
55		}
56	470	return ret;
57		}
58		}