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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: 155427 $ $Date: 2005-02-26 06:11:52 -0700 (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 name) {
33 super(name);
34 }
35
36
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
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
58 protected void setup() throws Exception {
59 super.setUp();
60 setTolerance(1E-6);
61 }
62
63
64
65 public void testCumulativeProbabilityExtremes() throws Exception {
66 setCumulativeTestPoints(new double[] {-2, 0});
67 setCumulativeTestValues(new double[] {0, 0});
68 verifyCumulativeProbabilities();
69 }
70
71 public void testInverseCumulativeProbabilityExtremes() throws Exception {
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 ex) {
89
90 }
91 try {
92 distribution.setDenominatorDegreesOfFreedom(0d);
93 fail("Expecting IllegalArgumentException for df = 0");
94 } catch (IllegalArgumentException ex) {
95
96 }
97 }
98
99 public void testLargeDegreesOfFreedom() throws Exception {
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 }