001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.math.distribution; 019 020 /** 021 * Test cases for CauchyDistribution. 022 * Extends ContinuousDistributionAbstractTest. See class javadoc for 023 * ContinuousDistributionAbstractTest for details. 024 * 025 * @version $Revision: 762087 $ $Date: 2009-04-05 10:20:18 -0400 (Sun, 05 Apr 2009) $ 026 */ 027 public class CauchyDistributionTest extends ContinuousDistributionAbstractTest { 028 029 /** 030 * Constructor for CauchyDistributionTest. 031 * @param arg0 032 */ 033 public CauchyDistributionTest(String arg0) { 034 super(arg0); 035 } 036 037 //-------------- Implementations for abstract methods ----------------------- 038 039 /** Creates the default continuous distribution instance to use in tests. */ 040 @Override 041 public ContinuousDistribution makeDistribution() { 042 return new CauchyDistributionImpl(1.2, 2.1); 043 } 044 045 /** Creates the default cumulative probability distribution test input values */ 046 @Override 047 public double[] makeCumulativeTestPoints() { 048 // quantiles computed using Mathematica 049 return new double[] {-667.2485619d, -65.6230835d, -25.48302995d, 050 -12.05887818d, -5.263135428d, 7.663135428d, 14.45887818d, 051 27.88302995d, 68.0230835d, 669.6485619d}; 052 } 053 054 /** Creates the default cumulative probability density test expected values */ 055 @Override 056 public double[] makeCumulativeTestValues() { 057 return new double[] {0.001d, 0.01d, 0.025d, 0.05d, 0.1d, 0.900d, 0.950d, 058 0.975d, 0.990d, 0.999d}; 059 } 060 061 //---------------------------- Additional test cases ------------------------- 062 063 public void testInverseCumulativeProbabilityExtremes() throws Exception { 064 setInverseCumulativeTestPoints(new double[] {0.0, 1.0}); 065 setInverseCumulativeTestValues( 066 new double[] {Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY}); 067 verifyInverseCumulativeProbabilities(); 068 } 069 070 public void testMedian() { 071 CauchyDistribution distribution = (CauchyDistribution) getDistribution(); 072 double expected = Math.random(); 073 distribution.setMedian(expected); 074 assertEquals(expected, distribution.getMedian(), 0.0); 075 } 076 077 public void testScale() { 078 CauchyDistribution distribution = (CauchyDistribution) getDistribution(); 079 double expected = Math.random(); 080 distribution.setScale(expected); 081 assertEquals(expected, distribution.getScale(), 0.0); 082 } 083 084 public void testSetScale() { 085 CauchyDistribution distribution = (CauchyDistribution) getDistribution(); 086 try { 087 distribution.setScale(0.0); 088 fail("Can not have 0.0 scale."); 089 } catch (IllegalArgumentException ex) { 090 // success 091 } 092 093 try { 094 distribution.setScale(-1.0); 095 fail("Can not have negative scale."); 096 } catch (IllegalArgumentException ex) { 097 // success 098 } 099 } 100 }