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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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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 static Test suite() {
55 TestSuite suite = new TestSuite(ListUnivariateImplTest.class);
56 suite.setName("Frequency Tests");
57 return suite;
58 }
59
60
61 public void testStats() {
62 List<Object> externalList = new ArrayList<Object>();
63
64 DescriptiveStatistics u = new ListUnivariateImpl( externalList );
65
66 assertEquals("total count",0,u.getN(),tolerance);
67 u.addValue(one);
68 u.addValue(two);
69 u.addValue(two);
70 u.addValue(three);
71 assertEquals("N",n,u.getN(),tolerance);
72 assertEquals("sum",sum,u.getSum(),tolerance);
73 assertEquals("sumsq",sumSq,u.getSumsq(),tolerance);
74 assertEquals("var",var,u.getVariance(),tolerance);
75 assertEquals("std",std,u.getStandardDeviation(),tolerance);
76 assertEquals("mean",mean,u.getMean(),tolerance);
77 assertEquals("min",min,u.getMin(),tolerance);
78 assertEquals("max",max,u.getMax(),tolerance);
79 u.clear();
80 assertEquals("total count",0,u.getN(),tolerance);
81 }
82
83 public void testN0andN1Conditions() throws Exception {
84 List<Object> list = new ArrayList<Object>();
85
86 DescriptiveStatistics u = new ListUnivariateImpl( list );
87
88 assertTrue("Mean of n = 0 set should be NaN", Double.isNaN( u.getMean() ) );
89 assertTrue("Standard Deviation of n = 0 set should be NaN", Double.isNaN( u.getStandardDeviation() ) );
90 assertTrue("Variance of n = 0 set should be NaN", Double.isNaN(u.getVariance() ) );
91
92 list.add( Double.valueOf(one));
93
94 assertTrue( "Mean of n = 1 set should be value of single item n1", u.getMean() == one);
95 assertTrue( "StdDev of n = 1 set should be zero, instead it is: " + u.getStandardDeviation(), u.getStandardDeviation() == 0);
96 assertTrue( "Variance of n = 1 set should be zero", u.getVariance() == 0);
97 }
98
99 public void testSkewAndKurtosis() {
100 DescriptiveStatistics u = new DescriptiveStatistics();
101
102 double[] testArray = { 12.5, 12, 11.8, 14.2, 14.9, 14.5, 21, 8.2, 10.3, 11.3, 14.1,
103 9.9, 12.2, 12, 12.1, 11, 19.8, 11, 10, 8.8, 9, 12.3 };
104 for( int i = 0; i < testArray.length; i++) {
105 u.addValue( testArray[i]);
106 }
107
108 assertEquals("mean", 12.40455, u.getMean(), 0.0001);
109 assertEquals("variance", 10.00236, u.getVariance(), 0.0001);
110 assertEquals("skewness", 1.437424, u.getSkewness(), 0.0001);
111 assertEquals("kurtosis", 2.37719, u.getKurtosis(), 0.0001);
112 }
113
114 public void testProductAndGeometricMean() throws Exception {
115 ListUnivariateImpl u = new ListUnivariateImpl(new ArrayList<Object>());
116 u.setWindowSize(10);
117
118 u.addValue( 1.0 );
119 u.addValue( 2.0 );
120 u.addValue( 3.0 );
121 u.addValue( 4.0 );
122
123 assertEquals( "Geometric mean not expected", 2.213364, u.getGeometricMean(), 0.00001 );
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127 for( int i = 0; i < 10; i++ ) {
128 u.addValue( i + 2 );
129 }
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132 assertEquals( "Geometric mean not expected", 5.755931, u.getGeometricMean(), 0.00001 );
133
134
135 }
136
137
138 public void testSerialization() {
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140 DescriptiveStatistics u = new ListUnivariateImpl();
141
142 assertEquals("total count",0,u.getN(),tolerance);
143 u.addValue(one);
144 u.addValue(two);
145
146 DescriptiveStatistics u2 = (DescriptiveStatistics)TestUtils.serializeAndRecover(u);
147
148 u2.addValue(two);
149 u2.addValue(three);
150
151 assertEquals("N",n,u2.getN(),tolerance);
152 assertEquals("sum",sum,u2.getSum(),tolerance);
153 assertEquals("sumsq",sumSq,u2.getSumsq(),tolerance);
154 assertEquals("var",var,u2.getVariance(),tolerance);
155 assertEquals("std",std,u2.getStandardDeviation(),tolerance);
156 assertEquals("mean",mean,u2.getMean(),tolerance);
157 assertEquals("min",min,u2.getMin(),tolerance);
158 assertEquals("max",max,u2.getMax(),tolerance);
159
160 u2.clear();
161 assertEquals("total count",0,u2.getN(),tolerance);
162 }
163 }
164