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18 package org.apache.commons.math.distribution;
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27 public class ChiSquareDistributionTest extends ContinuousDistributionAbstractTest {
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32
33 public ChiSquareDistributionTest(String name) {
34 super(name);
35 }
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38
39
40 @Override
41 public ContinuousDistribution makeDistribution() {
42 return new ChiSquaredDistributionImpl(5.0);
43 }
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45
46 @Override
47 public double[] makeCumulativeTestPoints() {
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49 return new double[] {0.210216d, 0.5542981d, 0.8312116d, 1.145476d, 1.610308d,
50 20.51501d, 15.08627d, 12.83250d, 11.07050d, 9.236357d};
51 }
52
53
54 @Override
55 public double[] makeCumulativeTestValues() {
56 return new double[] {0.001d, 0.01d, 0.025d, 0.05d, 0.1d, 0.999d,
57 0.990d, 0.975d, 0.950d, 0.900d};
58 }
59
60
61 @Override
62 public double[] makeInverseCumulativeTestPoints() {
63 return new double[] {0, 0.001d, 0.01d, 0.025d, 0.05d, 0.1d, 0.999d,
64 0.990d, 0.975d, 0.950d, 0.900d, 1};
65 }
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68 @Override
69 public double[] makeInverseCumulativeTestValues() {
70 return new double[] {0, 0.210216d, 0.5542981d, 0.8312116d, 1.145476d, 1.610308d,
71 20.51501d, 15.08627d, 12.83250d, 11.07050d, 9.236357d,
72 Double.POSITIVE_INFINITY};
73 }
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75
76 @Override
77 protected void setUp() throws Exception {
78 super.setUp();
79 setTolerance(5e-6);
80 }
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84 public void testSmallDf() throws Exception {
85 setDistribution(new ChiSquaredDistributionImpl(0.1d));
86 setTolerance(1E-4);
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88 setCumulativeTestPoints(new double[] {1.168926E-60, 1.168926E-40, 1.063132E-32,
89 1.144775E-26, 1.168926E-20, 5.472917, 2.175255, 1.13438,
90 0.5318646, 0.1526342});
91 setInverseCumulativeTestValues(getCumulativeTestPoints());
92 setInverseCumulativeTestPoints(getCumulativeTestValues());
93 verifyCumulativeProbabilities();
94 verifyInverseCumulativeProbabilities();
95 }
96
97 public void testDfAccessors() {
98 ChiSquaredDistribution distribution = (ChiSquaredDistribution) getDistribution();
99 assertEquals(5d, distribution.getDegreesOfFreedom(), Double.MIN_VALUE);
100 distribution.setDegreesOfFreedom(4d);
101 assertEquals(4d, distribution.getDegreesOfFreedom(), Double.MIN_VALUE);
102 try {
103 distribution.setDegreesOfFreedom(0d);
104 fail("Expecting IllegalArgumentException for df = 0");
105 } catch (IllegalArgumentException ex) {
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107 }
108 }
109
110 public void testDensity() {
111 double[] x = new double[]{-0.1, 1e-6, 0.5, 1, 2, 5};
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113 checkDensity(1, x, new double[]{0.00000000000, 398.94208093034, 0.43939128947, 0.24197072452, 0.10377687436, 0.01464498256});
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115 checkDensity(0.1, x, new double[]{0.000000000e+00, 2.486453997e+04, 7.464238732e-02, 3.009077718e-02, 9.447299159e-03, 8.827199396e-04});
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117 checkDensity(2, x, new double[]{0.00000000000, 0.49999975000, 0.38940039154, 0.30326532986, 0.18393972059, 0.04104249931});
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119 checkDensity(10, x, new double[]{0.000000000e+00, 1.302082682e-27, 6.337896998e-05, 7.897534632e-04, 7.664155024e-03, 6.680094289e-02});
120 }
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122 private void checkDensity(double df, double[] x, double[] expected) {
123 ChiSquaredDistribution d = new ChiSquaredDistributionImpl(df);
124 for (int i = 0; i < x.length; i++) {
125 assertEquals(expected[i], d.density(x[i]), 1e-5);
126 }
127 }
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129 }