@Test
public void testNextGamma() {
double[] quartiles;
long[] counts;
// Tests shape > 1, one case in the rejection sampling
quartiles = TestUtils.getDistributionQuartiles(new GammaDistribution(4, 2));
counts = new long[4];
randomData.reSeed(1000);
for (int i = 0; i < 1000; i++) {
double value = randomData.nextGamma(4, 2);
TestUtils.updateCounts(value, counts, quartiles);
}
TestUtils.assertChiSquareAccept(expected, counts, 0.001);
// Tests shape <= 1, another case in the rejection sampling
quartiles = TestUtils.getDistributionQuartiles(new GammaDistribution(0.3, 3));
counts = new long[4];
randomData.reSeed(1000);
for (int i = 0; i < 1000; i++) {
double value = randomData.nextGamma(0.3, 3);
TestUtils.updateCounts(value, counts, quartiles);
}
TestUtils.assertChiSquareAccept(expected, counts, 0.001);
}
@Test
public void testNextWeibull() {
double[] quartiles = TestUtils.getDistributionQuartiles(new WeibullDistribution(1.2, 2.1));
long[] counts = new long[4];
randomData.reSeed(1000);
for (int i = 0; i < 1000; i++) {
double value = randomData.nextWeibull(1.2, 2.1);
TestUtils.updateCounts(value, counts, quartiles);
}
TestUtils.assertChiSquareAccept(expected, counts, 0.001);
}
/** test failure modes and distribution of nextExponential() */
@Test
public void testNextExponential() {
try {
randomData.nextExponential(-1);
Assert.fail("negative mean -- expecting MathIllegalArgumentException");
} catch (MathIllegalArgumentException ex) {
// ignored
}
try {
randomData.nextExponential(0);
Assert.fail("zero mean -- expecting MathIllegalArgumentException");
} catch (MathIllegalArgumentException ex) {
// ignored
}
double[] quartiles;
long[] counts;
// Mean 1
quartiles = TestUtils.getDistributionQuartiles(new ExponentialDistribution(1));
counts = new long[4];
randomData.reSeed(1000);
for (int i = 0; i < 1000; i++) {
double value = randomData.nextExponential(1);
TestUtils.updateCounts(value, counts, quartiles);
}
TestUtils.assertChiSquareAccept(expected, counts, 0.001);
// Mean 5
quartiles = TestUtils.getDistributionQuartiles(new ExponentialDistribution(5));
counts = new long[4];
randomData.reSeed(1000);
for (int i = 0; i < 1000; i++) {
double value = randomData.nextExponential(5);
TestUtils.updateCounts(value, counts, quartiles);
}
TestUtils.assertChiSquareAccept(expected, counts, 0.001);
}
/** test failure modes and distribution of nextGaussian() */
@Test
public void testNextGaussian() {
try {
randomData.nextGaussian(0, 0);
Assert.fail("zero sigma -- MathIllegalArgumentException expected");
} catch (MathIllegalArgumentException ex) {
// ignored
}
double[] quartiles = TestUtils.getDistributionQuartiles(new NormalDistribution(0, 1));
long[] counts = new long[4];
randomData.reSeed(1000);
for (int i = 0; i < 1000; i++) {
double value = randomData.nextGaussian(0, 1);
TestUtils.updateCounts(value, counts, quartiles);
}
TestUtils.assertChiSquareAccept(expected, counts, 0.001);
}