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17 package org.apache.commons.math.stat.descriptive;
18
19 import java.util.ArrayList;
20 import java.util.List;
21
22 import org.apache.commons.math.TestUtils;
23
24 import junit.framework.Test;
25 import junit.framework.TestCase;
26 import junit.framework.TestSuite;
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32
33
34 public final class ListUnivariateImplTest extends TestCase {
35
36 private double one = 1;
37 private float two = 2;
38 private int three = 3;
39
40 private double mean = 2;
41 private double sumSq = 18;
42 private double sum = 8;
43 private double var = 0.666666666666666666667;
44 private double std = Math.sqrt(var);
45 private double n = 4;
46 private double min = 1;
47 private double max = 3;
48 private double tolerance = 10E-15;
49
50 public ListUnivariateImplTest(String name) {
51 super(name);
52 }
53
54 public void setUp() {
55 }
56
57 public static Test suite() {
58 TestSuite suite = new TestSuite(ListUnivariateImplTest.class);
59 suite.setName("Frequency Tests");
60 return suite;
61 }
62
63
64 public void testStats() {
65 List externalList = new ArrayList();
66
67 DescriptiveStatistics u = new ListUnivariateImpl( externalList );
68
69 assertEquals("total count",0,u.getN(),tolerance);
70 u.addValue(one);
71 u.addValue(two);
72 u.addValue(two);
73 u.addValue(three);
74 assertEquals("N",n,u.getN(),tolerance);
75 assertEquals("sum",sum,u.getSum(),tolerance);
76 assertEquals("sumsq",sumSq,u.getSumsq(),tolerance);
77 assertEquals("var",var,u.getVariance(),tolerance);
78 assertEquals("std",std,u.getStandardDeviation(),tolerance);
79 assertEquals("mean",mean,u.getMean(),tolerance);
80 assertEquals("min",min,u.getMin(),tolerance);
81 assertEquals("max",max,u.getMax(),tolerance);
82 u.clear();
83 assertEquals("total count",0,u.getN(),tolerance);
84 }
85
86 public void testN0andN1Conditions() throws Exception {
87 List list = new ArrayList();
88
89 DescriptiveStatistics u = new ListUnivariateImpl( list );
90
91 assertTrue("Mean of n = 0 set should be NaN", Double.isNaN( u.getMean() ) );
92 assertTrue("Standard Deviation of n = 0 set should be NaN", Double.isNaN( u.getStandardDeviation() ) );
93 assertTrue("Variance of n = 0 set should be NaN", Double.isNaN(u.getVariance() ) );
94
95 list.add( new Double(one));
96
97 assertTrue( "Mean of n = 1 set should be value of single item n1", u.getMean() == one);
98 assertTrue( "StdDev of n = 1 set should be zero, instead it is: " + u.getStandardDeviation(), u.getStandardDeviation() == 0);
99 assertTrue( "Variance of n = 1 set should be zero", u.getVariance() == 0);
100 }
101
102 public void testSkewAndKurtosis() {
103 DescriptiveStatistics u = new DescriptiveStatistics();
104
105 double[] testArray = { 12.5, 12, 11.8, 14.2, 14.9, 14.5, 21, 8.2, 10.3, 11.3, 14.1,
106 9.9, 12.2, 12, 12.1, 11, 19.8, 11, 10, 8.8, 9, 12.3 };
107 for( int i = 0; i < testArray.length; i++) {
108 u.addValue( testArray[i]);
109 }
110
111 assertEquals("mean", 12.40455, u.getMean(), 0.0001);
112 assertEquals("variance", 10.00236, u.getVariance(), 0.0001);
113 assertEquals("skewness", 1.437424, u.getSkewness(), 0.0001);
114 assertEquals("kurtosis", 2.37719, u.getKurtosis(), 0.0001);
115 }
116
117 public void testProductAndGeometricMean() throws Exception {
118 ListUnivariateImpl u = new ListUnivariateImpl(new ArrayList());
119 u.setWindowSize(10);
120
121 u.addValue( 1.0 );
122 u.addValue( 2.0 );
123 u.addValue( 3.0 );
124 u.addValue( 4.0 );
125
126 assertEquals( "Geometric mean not expected", 2.213364, u.getGeometricMean(), 0.00001 );
127
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129
130 for( int i = 0; i < 10; i++ ) {
131 u.addValue( i + 2 );
132 }
133
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135 assertEquals( "Geometric mean not expected", 5.755931, u.getGeometricMean(), 0.00001 );
136
137
138 }
139
140
141 public void testSerialization() {
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143 DescriptiveStatistics u = new ListUnivariateImpl();
144
145 assertEquals("total count",0,u.getN(),tolerance);
146 u.addValue(one);
147 u.addValue(two);
148
149 DescriptiveStatistics u2 = (DescriptiveStatistics)TestUtils.serializeAndRecover(u);
150
151 u2.addValue(two);
152 u2.addValue(three);
153
154 assertEquals("N",n,u2.getN(),tolerance);
155 assertEquals("sum",sum,u2.getSum(),tolerance);
156 assertEquals("sumsq",sumSq,u2.getSumsq(),tolerance);
157 assertEquals("var",var,u2.getVariance(),tolerance);
158 assertEquals("std",std,u2.getStandardDeviation(),tolerance);
159 assertEquals("mean",mean,u2.getMean(),tolerance);
160 assertEquals("min",min,u2.getMin(),tolerance);
161 assertEquals("max",max,u2.getMax(),tolerance);
162
163 u2.clear();
164 assertEquals("total count",0,u2.getN(),tolerance);
165 }
166 }
167