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Java > Open Source Codes > org > apache > commons > math > distribution > FDistributionTest


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.distribution;
17
18
19 /**
20  * Test cases for FDistribution.
21  * Extends ContinuousDistributionAbstractTest. See class javadoc for
22  * ContinuousDistributionAbstractTest for details.
23  *
24  * @version $Revision$ $Date: 2005-02-26 05:11:52 -0800 (Sat, 26 Feb 2005) $
25  */
26 public class FDistributionTest extends ContinuousDistributionAbstractTest {
27
28     /**
29      * Constructor for FDistributionTest.
30      * @param name
31      */
32     public FDistributionTest(String JavaDoc name) {
33         super(name);
34     }
35
36     //-------------- Implementations for abstract methods -----------------------
37
38     /** Creates the default continuous distribution instance to use in tests. */
39     public ContinuousDistribution makeDistribution() {
40         return DistributionFactory.newInstance().createFDistribution(5.0, 6.0);
41     }
42     
43     /** Creates the default cumulative probability distribution test input values */
44     public double[] makeCumulativeTestPoints() {
45         // quantiles computed using R version 1.8.1 (linux version)
46 return new double[] {0.03468084d ,0.09370091d, 0.1433137d,
47             0.2020084d, 0.2937283d, 20.80266d, 8.745895d, 5.987565d,
48             4.387374d, 3.107512d};
49     }
50     
51     /** Creates the default cumulative probability density test expected values */
52     public double[] makeCumulativeTestValues() {
53         return new double[] {0.001d, 0.01d, 0.025d, 0.05d, 0.1d, 0.999d,
54                 0.990d, 0.975d, 0.950d, 0.900d};
55     }
56     
57     // --------------------- Override tolerance --------------
58 protected void setup() throws Exception JavaDoc {
59         super.setUp();
60         setTolerance(1E-6);
61     }
62
63     //---------------------------- Additional test cases -------------------------
64
65     public void testCumulativeProbabilityExtremes() throws Exception JavaDoc {
66         setCumulativeTestPoints(new double[] {-2, 0});
67         setCumulativeTestValues(new double[] {0, 0});
68         verifyCumulativeProbabilities();
69     }
70
71     public void testInverseCumulativeProbabilityExtremes() throws Exception JavaDoc {
72         setInverseCumulativeTestPoints(new double[] {0, 1});
73         setInverseCumulativeTestValues(new double[] {0, Double.POSITIVE_INFINITY});
74         verifyInverseCumulativeProbabilities();
75     }
76     
77     public void testDfAccessors() {
78         FDistribution distribution = (FDistribution) getDistribution();
79         assertEquals(5d, distribution.getNumeratorDegreesOfFreedom(), Double.MIN_VALUE);
80         distribution.setNumeratorDegreesOfFreedom(4d);
81         assertEquals(4d, distribution.getNumeratorDegreesOfFreedom(), Double.MIN_VALUE);
82         assertEquals(6d, distribution.getDenominatorDegreesOfFreedom(), Double.MIN_VALUE);
83         distribution.setDenominatorDegreesOfFreedom(4d);
84         assertEquals(4d, distribution.getDenominatorDegreesOfFreedom(), Double.MIN_VALUE);
85         try {
86             distribution.setNumeratorDegreesOfFreedom(0d);
87             fail("Expecting IllegalArgumentException for df = 0");
88         } catch (IllegalArgumentException JavaDoc ex) {
89             // expected
90 }
91         try {
92             distribution.setDenominatorDegreesOfFreedom(0d);
93             fail("Expecting IllegalArgumentException for df = 0");
94         } catch (IllegalArgumentException JavaDoc ex) {
95             // expected
96 }
97     }
98
99     public void testLargeDegreesOfFreedom() throws Exception JavaDoc {
100         org.apache.commons.math.distribution.FDistributionImpl fd =
101             new org.apache.commons.math.distribution.FDistributionImpl(
102                 100000., 100000.);
103         double p = fd.cumulativeProbability(.999);
104         double x = fd.inverseCumulativeProbability(p);
105         assertEquals(.999, x, 1.0e-5);
106     }
107 }
108
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