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16 package org.apache.commons.math.stat.descriptive;
17
18 import java.util.ArrayList  ;
19 import java.util.List ;
20
21 import org.apache.commons.math.TestUtils;
22
23 import junit.framework.Test;
24 import junit.framework.TestCase;
25 import junit.framework.TestSuite;
26
27
32
33 public final class ListUnivariateImplTest extends TestCase {
34
35 private double one = 1;
36 private float two = 2;
37 private int three = 3;
38
39 private double mean = 2;
40 private double sumSq = 18;
41 private double sum = 8;
42 private double var = 0.666666666666666666667;
43 private double std = Math.sqrt(var);
44 private double n = 4;
45 private double min = 1;
46 private double max = 3;
47 private double skewness = 0;
48 private double kurtosis = 0.5;
49 private double tolerance = 10E-15;
50
51 public ListUnivariateImplTest(String name) {
52 super(name);
53 }
54
55 public void setUp() {
56 }
57
58 public static Test suite() {
59 TestSuite suite = new TestSuite(ListUnivariateImplTest.class);
60 suite.setName("Frequency Tests");
61 return suite;
62 }
63
64
65 public void testStats() {
66 List externalList = new ArrayList ();
67
68 DescriptiveStatistics u = new ListUnivariateImpl( externalList );
69
70 assertEquals("total count",0,u.getN(),tolerance);
71 u.addValue(one);
72 u.addValue(two);
73 u.addValue(two);
74 u.addValue(three);
75 assertEquals("N",n,u.getN(),tolerance);
76 assertEquals("sum",sum,u.getSum(),tolerance);
77 assertEquals("sumsq",sumSq,u.getSumsq(),tolerance);
78 assertEquals("var",var,u.getVariance(),tolerance);
79 assertEquals("std",std,u.getStandardDeviation(),tolerance);
80 assertEquals("mean",mean,u.getMean(),tolerance);
81 assertEquals("min",min,u.getMin(),tolerance);
82 assertEquals("max",max,u.getMax(),tolerance);
83 u.clear();
84 assertEquals("total count",0,u.getN(),tolerance);
85 }
86
87 public void testN0andN1Conditions() throws Exception {
88 List list = new ArrayList ();
89
90 DescriptiveStatistics u = new ListUnivariateImpl( list );
91
92 assertTrue("Mean of n = 0 set should be NaN", Double.isNaN( u.getMean() ) );
93 assertTrue("Standard Deviation of n = 0 set should be NaN", Double.isNaN( u.getStandardDeviation() ) );
94 assertTrue("Variance of n = 0 set should be NaN", Double.isNaN(u.getVariance() ) );
95
96 list.add( new Double (one));
97
98 assertTrue( "Mean of n = 1 set should be value of single item n1", u.getMean() == one);
99 assertTrue( "StdDev of n = 1 set should be zero, instead it is: " + u.getStandardDeviation(), u.getStandardDeviation() == 0);
100 assertTrue( "Variance of n = 1 set should be zero", u.getVariance() == 0);
101 }
102
103 public void testSkewAndKurtosis() {
104 DescriptiveStatistics u = DescriptiveStatistics.newInstance();
105
106 double[] testArray = { 12.5, 12, 11.8, 14.2, 14.9, 14.5, 21, 8.2, 10.3, 11.3, 14.1,
107 9.9, 12.2, 12, 12.1, 11, 19.8, 11, 10, 8.8, 9, 12.3 };
108 for( int i = 0; i < testArray.length; i++) {
109 u.addValue( testArray[i]);
110 }
111
112 assertEquals("mean", 12.40455, u.getMean(), 0.0001);
113 assertEquals("variance", 10.00236, u.getVariance(), 0.0001);
114 assertEquals("skewness", 1.437424, u.getSkewness(), 0.0001);
115 assertEquals("kurtosis", 2.37719, u.getKurtosis(), 0.0001);
116 }
117
118 public void testProductAndGeometricMean() throws Exception {
119 ListUnivariateImpl u = new ListUnivariateImpl(new ArrayList ());
120 u.setWindowSize(10);
121
122 u.addValue( 1.0 );
123 u.addValue( 2.0 );
124 u.addValue( 3.0 );
125 u.addValue( 4.0 );
126
127 assertEquals( "Geometric mean not expected", 2.213364, u.getGeometricMean(), 0.00001 );
128
129 for( int i = 0; i < 10; i++ ) {
132 u.addValue( i + 2 );
133 }
134
136 assertEquals( "Geometric mean not expected", 5.755931, u.getGeometricMean(), 0.00001 );
137
138
139 }
140
141
142 public void testSerialization() {
143
144 DescriptiveStatistics u = null;
145
146 try {
147 u = DescriptiveStatistics.newInstance(ListUnivariateImpl.class);
148 } catch (InstantiationException e) {
149 fail(e.getMessage());
150 } catch (IllegalAccessException e) {
151 fail(e.getMessage());
152 }
153
154 assertEquals("total count",0,u.getN(),tolerance);
155 u.addValue(one);
156 u.addValue(two);
157
158 DescriptiveStatistics u2 = (DescriptiveStatistics)TestUtils.serializeAndRecover(u);
159
160 u2.addValue(two);
161 u2.addValue(three);
162
163 assertEquals("N",n,u2.getN(),tolerance);
164 assertEquals("sum",sum,u2.getSum(),tolerance);
165 assertEquals("sumsq",sumSq,u2.getSumsq(),tolerance);
166 assertEquals("var",var,u2.getVariance(),tolerance);
167 assertEquals("std",std,u2.getStandardDeviation(),tolerance);
168 assertEquals("mean",mean,u2.getMean(),tolerance);
169 assertEquals("min",min,u2.getMin(),tolerance);
170 assertEquals("max",max,u2.getMax(),tolerance);
171
172 u2.clear();
173 assertEquals("total count",0,u2.getN(),tolerance);
174 }
175 }
176
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