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Java > Open Source Codes > org > apache > commons > math > special > GammaTest


1 /*
2  * Copyright 2003-2004 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 org.apache.commons.math.MathException;
19 import org.apache.commons.math.TestUtils;
20
21 import junit.framework.TestCase;
22
23 /**
24  * @version $Revision$ $Date: 2005-02-26 05:11:52 -0800 (Sat, 26 Feb 2005) $
25  */
26 public class GammaTest extends TestCase {
27     /**
28      * Constructor for BetaTest.
29      * @param name
30      */
31     public GammaTest(String JavaDoc name) {
32         super(name);
33     }
34
35     private void testRegularizedGamma(double expected, double a, double x) {
36         try {
37             double actualP = Gamma.regularizedGammaP(a, x);
38             double actualQ = Gamma.regularizedGammaQ(a, x);
39             TestUtils.assertEquals(expected, actualP, 10e-5);
40             TestUtils.assertEquals(actualP, 1.0 - actualQ, 10e-5);
41         } catch(MathException ex){
42             fail(ex.getMessage());
43         }
44     }
45
46     private void testLogGamma(double expected, double x) {
47         double actual = Gamma.logGamma(x);
48         TestUtils.assertEquals(expected, actual, 10e-5);
49     }
50
51     public void testRegularizedGammaNanPositive() {
52         testRegularizedGamma(Double.NaN, Double.NaN, 1.0);
53     }
54
55     public void testRegularizedGammaPositiveNan() {
56         testRegularizedGamma(Double.NaN, 1.0, Double.NaN);
57     }
58     
59     public void testRegularizedGammaNegativePositive() {
60         testRegularizedGamma(Double.NaN, -1.5, 1.0);
61     }
62     
63     public void testRegularizedGammaPositiveNegative() {
64         testRegularizedGamma(Double.NaN, 1.0, -1.0);
65     }
66     
67     public void testRegularizedGammaZeroPositive() {
68         testRegularizedGamma(Double.NaN, 0.0, 1.0);
69     }
70     
71     public void testRegularizedGammaPositiveZero() {
72         testRegularizedGamma(0.0, 1.0, 0.0);
73     }
74     
75     public void testRegularizedGammaPositivePositive() {
76         testRegularizedGamma(0.632121, 1.0, 1.0);
77     }
78     
79     public void testLogGammaNan() {
80         testLogGamma(Double.NaN, Double.NaN);
81     }
82     
83     public void testLogGammaNegative() {
84         testLogGamma(Double.NaN, -1.0);
85     }
86     
87     public void testLogGammaZero() {
88         testLogGamma(Double.NaN, 0.0);
89     }
90     
91     public void testLogGammaPositive() {
92         testLogGamma(0.693147, 3.0);
93     }
94 }
95
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