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 WeibullDistribution.
22   * Extends ContinuousDistributionAbstractTest.  See class javadoc for
23   * ContinuousDistributionAbstractTest for details.
24   * 
25   * @version $Revision: 1.8 $ $Date: 2004-07-24 16:41:37 -0500 (Sat, 24 Jul 2004) $
26   */
27  public class WeibullDistributionTest extends ContinuousDistributionAbstractTest  {
28      
29      /**
30       * Constructor for CauchyDistributionTest.
31       * @param arg0
32       */
33      public WeibullDistributionTest(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      public ContinuousDistribution makeDistribution() {
41          return new WeibullDistributionImpl(1.2, 2.1);
42      }   
43      
44      /** Creates the default cumulative probability distribution test input values */
45      public double[] makeCumulativeTestPoints() {
46          // quantiles computed using Mathematica 
47          return new double[] {0.00664355181d, 0.04543282833d, 0.09811627374d,
48                  0.1767135246d, 0.3219468654d, 4.207902826d, 5.23968437d,
49                  6.232056007d, 7.497630467d, 10.51154969d};
50      }
51      
52      /** Creates the default cumulative probability density test expected values */
53      public double[] makeCumulativeTestValues() {
54          return new double[] {0.001d, 0.01d, 0.025d, 0.05d, 0.1d, 0.900d, 0.950d,
55                  0.975d, 0.990d, 0.999d};
56      }
57      
58      //---------------------------- Additional test cases -------------------------
59      
60      public void testInverseCumulativeProbabilityExtremes() throws Exception {
61          setInverseCumulativeTestPoints(new double[] {0.0, 1.0});
62          setInverseCumulativeTestValues(
63                  new double[] {0.0, Double.POSITIVE_INFINITY});
64          verifyInverseCumulativeProbabilities();
65      }
66      
67      public void testAlpha() {
68          WeibullDistribution distribution = (WeibullDistribution) getDistribution();
69          double expected = Math.random();
70          distribution.setShape(expected);
71          assertEquals(expected, distribution.getShape(), 0.0);
72      }
73      
74      public void testBeta() {
75          WeibullDistribution distribution = (WeibullDistribution) getDistribution();
76          double expected = Math.random();
77          distribution.setScale(expected);
78          assertEquals(expected, distribution.getScale(), 0.0);
79      }
80      
81      public void testSetAlpha() {
82          WeibullDistribution distribution = (WeibullDistribution) getDistribution();
83          try {
84              distribution.setShape(0.0);
85              fail("Can not have 0.0 alpha.");
86          } catch (IllegalArgumentException ex) {
87              // success
88          }
89          
90          try {
91              distribution.setShape(-1.0);
92              fail("Can not have negative alpha.");
93          } catch (IllegalArgumentException ex) {
94              // success
95          }
96      }
97      
98      public void testSetBeta() {
99          WeibullDistribution distribution = (WeibullDistribution) getDistribution();
100         try {
101             distribution.setScale(0.0);
102             fail("Can not have 0.0 beta.");
103         } catch (IllegalArgumentException ex) {
104             // success
105         }
106         
107         try {
108             distribution.setScale(-1.0);
109             fail("Can not have negative beta.");
110         } catch (IllegalArgumentException ex) {
111             // success
112         }
113     }
114 }