1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.math.distribution;
19
20 /**
21 * Test cases for CauchyDistribution.
22 * Extends ContinuousDistributionAbstractTest. See class javadoc for
23 * ContinuousDistributionAbstractTest for details.
24 *
25 * @version $Revision: 762087 $ $Date: 2009-04-05 10:20:18 -0400 (Sun, 05 Apr 2009) $
26 */
27 public class CauchyDistributionTest extends ContinuousDistributionAbstractTest {
28
29 /**
30 * Constructor for CauchyDistributionTest.
31 * @param arg0
32 */
33 public CauchyDistributionTest(String arg0) {
34 super(arg0);
35 }
36
37 //-------------- Implementations for abstract methods -----------------------
38
39 /** Creates the default continuous distribution instance to use in tests. */
40 @Override
41 public ContinuousDistribution makeDistribution() {
42 return new CauchyDistributionImpl(1.2, 2.1);
43 }
44
45 /** Creates the default cumulative probability distribution test input values */
46 @Override
47 public double[] makeCumulativeTestPoints() {
48 // quantiles computed using Mathematica
49 return new double[] {-667.2485619d, -65.6230835d, -25.48302995d,
50 -12.05887818d, -5.263135428d, 7.663135428d, 14.45887818d,
51 27.88302995d, 68.0230835d, 669.6485619d};
52 }
53
54 /** Creates the default cumulative probability density test expected values */
55 @Override
56 public double[] makeCumulativeTestValues() {
57 return new double[] {0.001d, 0.01d, 0.025d, 0.05d, 0.1d, 0.900d, 0.950d,
58 0.975d, 0.990d, 0.999d};
59 }
60
61 //---------------------------- Additional test cases -------------------------
62
63 public void testInverseCumulativeProbabilityExtremes() throws Exception {
64 setInverseCumulativeTestPoints(new double[] {0.0, 1.0});
65 setInverseCumulativeTestValues(
66 new double[] {Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY});
67 verifyInverseCumulativeProbabilities();
68 }
69
70 public void testMedian() {
71 CauchyDistribution distribution = (CauchyDistribution) getDistribution();
72 double expected = Math.random();
73 distribution.setMedian(expected);
74 assertEquals(expected, distribution.getMedian(), 0.0);
75 }
76
77 public void testScale() {
78 CauchyDistribution distribution = (CauchyDistribution) getDistribution();
79 double expected = Math.random();
80 distribution.setScale(expected);
81 assertEquals(expected, distribution.getScale(), 0.0);
82 }
83
84 public void testSetScale() {
85 CauchyDistribution distribution = (CauchyDistribution) getDistribution();
86 try {
87 distribution.setScale(0.0);
88 fail("Can not have 0.0 scale.");
89 } catch (IllegalArgumentException ex) {
90 // success
91 }
92
93 try {
94 distribution.setScale(-1.0);
95 fail("Can not have negative scale.");
96 } catch (IllegalArgumentException ex) {
97 // success
98 }
99 }
100 }