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16 package org.apache.commons.math.stat.descriptive;
17
18 import junit.framework.Test;
19 import junit.framework.TestCase;
20 import junit.framework.TestSuite;
21
22 import org.apache.commons.math.random.RandomData;
23 import org.apache.commons.math.random.RandomDataImpl;
24
25
30
31 public final class DescriptiveStatisticsImplTest extends TestCase {
32 private double one = 1;
33 private float two = 2;
34 private int three = 3;
35 private double mean = 2;
36 private double sumSq = 18;
37 private double sum = 8;
38 private double var = 0.666666666666666666667;
39 private double std = Math.sqrt(var);
40 private double n = 4;
41 private double min = 1;
42 private double max = 3;
43 private double skewness = 0;
44 private double kurtosis = 0.5;
45 private double tolerance = 10E-15;
46
47 public DescriptiveStatisticsImplTest(String  name) {
48 super(name);
49 }
50
51 public void setUp() {
52 }
53
54 public static Test suite() {
55 TestSuite suite = new TestSuite(DescriptiveStatisticsImplTest.class);
56 suite.setName("DescriptiveStatistics Tests");
57 return suite;
58 }
59
60
61 public void testStats() {
62 DescriptiveStatistics u = DescriptiveStatistics.newInstance();
63 assertEquals("total count",0,u.getN(),tolerance);
64 u.addValue(one);
65 u.addValue(two);
66 u.addValue(two);
67 u.addValue(three);
68 assertEquals("N",n,u.getN(),tolerance);
69 assertEquals("sum",sum,u.getSum(),tolerance);
70 assertEquals("sumsq",sumSq,u.getSumsq(),tolerance);
71 assertEquals("var",var,u.getVariance(),tolerance);
72 assertEquals("std",std,u.getStandardDeviation(),tolerance);
73 assertEquals("mean",mean,u.getMean(),tolerance);
74 assertEquals("min",min,u.getMin(),tolerance);
75 assertEquals("max",max,u.getMax(),tolerance);
76 u.clear();
77 assertEquals("total count",0,u.getN(),tolerance);
78 }
79
80 public void testN0andN1Conditions() throws Exception {
81 DescriptiveStatistics u = DescriptiveStatistics.newInstance();
82
83 assertTrue("Mean of n = 0 set should be NaN",
84 Double.isNaN( u.getMean() ) );
85 assertTrue("Standard Deviation of n = 0 set should be NaN",
86 Double.isNaN( u.getStandardDeviation() ) );
87 assertTrue("Variance of n = 0 set should be NaN",
88 Double.isNaN(u.getVariance() ) );
89
90 u.addValue(one);
91
92 assertTrue( "Mean of n = 1 set should be value of single item n1",
93 u.getMean() == one);
94 assertTrue( "StdDev of n = 1 set should be zero, instead it is: "
95 + u.getStandardDeviation(), u.getStandardDeviation() == 0);
96 assertTrue( "Variance of n = 1 set should be zero",
97 u.getVariance() == 0);
98 }
99
100 public void testSkewAndKurtosis() {
101 DescriptiveStatistics u = DescriptiveStatistics.newInstance();
102
103 double[] testArray =
104 { 12.5, 12, 11.8, 14.2, 14.9, 14.5, 21, 8.2, 10.3, 11.3, 14.1,
105 9.9, 12.2, 12, 12.1, 11, 19.8, 11, 10, 8.8, 9, 12.3 };
106 for( int i = 0; i < testArray.length; i++) {
107 u.addValue( testArray[i]);
108 }
109
110 assertEquals("mean", 12.40455, u.getMean(), 0.0001);
111 assertEquals("variance", 10.00236, u.getVariance(), 0.0001);
112 assertEquals("skewness", 1.437424, u.getSkewness(), 0.0001);
113 assertEquals("kurtosis", 2.37719, u.getKurtosis(), 0.0001);
114 }
115
116 public void testProductAndGeometricMean() throws Exception {
117 DescriptiveStatistics u = DescriptiveStatistics.newInstance();
118 u.setWindowSize(10);
119
120 u.addValue( 1.0 );
121 u.addValue( 2.0 );
122 u.addValue( 3.0 );
123 u.addValue( 4.0 );
124
125 assertEquals( "Geometric mean not expected",
128 2.213364, u.getGeometricMean(), 0.00001 );
129
130 for( int i = 0; i < 10; i++ ) {
133 u.addValue( i + 2 );
134 }
135
137 assertEquals( "Geometric mean not expected", 5.755931,
140 u.getGeometricMean(), 0.00001 );
141 }
142
143 public void testGetSortedValues() {
144 double[] test1 = {5,4,3,2,1};
145 double[] test2 = {5,2,1,3,4,0};
146 double[] test3 = {1};
147 int[] testi = null;
148 double[] test4 = null;
149 RandomData rd = new RandomDataImpl();
150 tstGetSortedValues(test1);
151 tstGetSortedValues(test2);
152 tstGetSortedValues(test3);
153 for (int i = 0; i < 10; i++) {
154 testi = rd.nextPermutation(10,6);
155 test4 = new double[6];
156 for (int j = 0; j < testi.length; j++) {
157 test4[j] = (double) testi[j];
158 }
159 tstGetSortedValues(test4);
160 }
161 for (int i = 0; i < 10; i++) {
162 testi = rd.nextPermutation(10,5);
163 test4 = new double[5];
164 for (int j = 0; j < testi.length; j++) {
165 test4[j] = (double) testi[j];
166 }
167 tstGetSortedValues(test4);
168 }
169 }
170
171
172 private void tstGetSortedValues(double[] test) {
173 DescriptiveStatistics u = DescriptiveStatistics.newInstance();
174 for (int i = 0; i < test.length; i++) {
175 u.addValue(test[i]);
176 }
177 double[] sorted = u.getSortedValues();
178 if (sorted.length != test.length) {
179 fail("wrong length for sorted values array");
180 }
181 for (int i = 0; i < sorted.length-1; i++) {
182 if (sorted[i] > sorted[i+1]) {
183 fail("sorted values out of sequence");
184 }
185 }
186 }
187
188 public void testPercentiles() {
189 double[] test = {5,4,3,2,1};
190 DescriptiveStatistics u = DescriptiveStatistics.newInstance();
191 for (int i = 0; i < test.length; i++) {
192 u.addValue(test[i]);
193 }
194 assertEquals("expecting min",1,u.getPercentile(5),10E-12);
195 assertEquals("expecting max",5,u.getPercentile(99),10E-12);
196 assertEquals("expecting middle",3,u.getPercentile(50),10E-12);
197 try {
198 double x = u.getPercentile(0);
199 fail("expecting IllegalArgumentException for getPercentile(0)");
200 } catch (IllegalArgumentException ex) {
201 ;
202 }
203 try {
204 double x = u.getPercentile(120);
205 fail("expecting IllegalArgumentException for getPercentile(120)");
206 } catch (IllegalArgumentException ex) {
207 ;
208 }
209
210 u.clear();
211 double[] test2 = {1,2,3,4};
212 for (int i = 0; i < test2.length; i++) {
213 u.addValue(test2[i]);
214 }
215 assertEquals("Q1",1.25,u.getPercentile(25),10E-12);
216 assertEquals("Q3",3.75,u.getPercentile(75),10E-12);
217 assertEquals("Q2",2.5,u.getPercentile(50),10E-12);
218
219 u.clear();
220 double[] test3 = {1};
221 for (int i = 0; i < test3.length; i++) {
222 u.addValue(test3[i]);
223 }
224 assertEquals("Q1",1,u.getPercentile(25),10E-12);
225 assertEquals("Q3",1,u.getPercentile(75),10E-12);
226 assertEquals("Q2",1,u.getPercentile(50),10E-12);
227
228 u.clear();
229 RandomData rd = new RandomDataImpl();
230 int[] testi = rd.nextPermutation(100,100); for (int j = 0; j < testi.length; j++) {
232 u.addValue((double) testi[j]); }
234 for (int i = 1; i < 100; i++) {
235 assertEquals("percentile " + i,
236 (double) i-1 + (double) i*(.01), u.getPercentile(i),10E-12);
237 }
238
239 u.clear();
240 double[] test4 = {1,2,3,4,100};
241 for (int i = 0; i < test4.length; i++) {
242 u.addValue(test4[i]);
243 }
244 assertEquals("80th",80.8,u.getPercentile(80),10E-12);
245
246 u.clear();
247 assertTrue("empty value set should return NaN",
248 Double.isNaN(u.getPercentile(50)));
249 }
250
251 }
252
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