/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math4.distribution;
import org.apache.commons.math4.distribution.IntegerDistribution;
import org.apache.commons.math4.distribution.NormalDistribution;
import org.apache.commons.math4.distribution.PascalDistribution;
import org.junit.Assert;
import org.junit.Test;
/**
* Test cases for PascalDistribution.
* Extends IntegerDistributionAbstractTest. See class javadoc for
* IntegerDistributionAbstractTest for details.
*
*/
public class PascalDistributionTest extends IntegerDistributionAbstractTest {
// --------------------- Override tolerance --------------
protected double defaultTolerance = NormalDistribution.DEFAULT_INVERSE_ABSOLUTE_ACCURACY;
@Override
public void setUp() {
super.setUp();
setTolerance(defaultTolerance);
}
//-------------- Implementations for abstract methods -----------------------
/** Creates the default discrete distribution instance to use in tests. */
@Override
public IntegerDistribution makeDistribution() {
return new PascalDistribution(10,0.70);
}
/** Creates the default probability density test input values */
@Override
public int[] makeDensityTestPoints() {
return new int[] {-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11};
}
/** Creates the default probability density test expected values */
@Override
public double[] makeDensityTestValues() {
return new double[] {0, 0.0282475249, 0.0847425747, 0.139825248255, 0.167790297906, 0.163595540458,
0.137420253985, 0.103065190489, 0.070673273478, 0.0450542118422, 0.0270325271053,
0.0154085404500, 0.0084046584273};
}
/** Creates the default cumulative probability density test input values */
@Override
public int[] makeCumulativeTestPoints() {
return makeDensityTestPoints();
}
/** Creates the default cumulative probability density test expected values */
@Override
public double[] makeCumulativeTestValues() {
return new double[] {0, 0.0282475249, 0.1129900996, 0.252815347855, 0.420605645761, 0.584201186219,
0.721621440204, 0.824686630693, 0.895359904171, 0.940414116013, 0.967446643119,
0.982855183569, 0.991259841996};
}
/** Creates the default inverse cumulative probability test input values */
@Override
public double[] makeInverseCumulativeTestPoints() {
return new double[] {0.0, 0.001, 0.010, 0.025, 0.050, 0.100, 0.999,
0.990, 0.975, 0.950, 0.900, 1.0};
}
/** Creates the default inverse cumulative probability density test expected values */
@Override
public int[] makeInverseCumulativeTestValues() {
return new int[] {0, 0, 0, 0, 1, 1, 14, 11, 10, 9, 8, Integer.MAX_VALUE};
}
//----------------- Additional test cases ---------------------------------
/** Test degenerate case p = 0 */
@Test
public void testDegenerate0() {
setDistribution(new PascalDistribution(5, 0.0d));
setCumulativeTestPoints(new int[] {-1, 0, 1, 5, 10 });
setCumulativeTestValues(new double[] {0d, 0d, 0d, 0d, 0d});
setDensityTestPoints(new int[] {-1, 0, 1, 10, 11});
setDensityTestValues(new double[] {0d, 0d, 0d, 0d, 0d});
setInverseCumulativeTestPoints(new double[] {0.1d, 0.5d});
setInverseCumulativeTestValues(new int[] {Integer.MAX_VALUE, Integer.MAX_VALUE});
verifyDensities();
verifyCumulativeProbabilities();
verifyInverseCumulativeProbabilities();
}
/** Test degenerate case p = 1 */
@Test
public void testDegenerate1() {
setDistribution(new PascalDistribution(5, 1.0d));
setCumulativeTestPoints(new int[] {-1, 0, 1, 2, 5, 10 });
setCumulativeTestValues(new double[] {0d, 1d, 1d, 1d, 1d, 1d});
setDensityTestPoints(new int[] {-1, 0, 1, 2, 5, 10});
setDensityTestValues(new double[] {0d, 1d, 0d, 0d, 0d, 0d});
setInverseCumulativeTestPoints(new double[] {0.1d, 0.5d});
setInverseCumulativeTestValues(new int[] {0, 0});
verifyDensities();
verifyCumulativeProbabilities();
verifyInverseCumulativeProbabilities();
}
@Test
public void testMoments() {
final double tol = 1e-9;
PascalDistribution dist;
dist = new PascalDistribution(10, 0.5);
Assert.assertEquals(dist.getNumericalMean(), ( 10d * 0.5d ) / 0.5d, tol);
Assert.assertEquals(dist.getNumericalVariance(), ( 10d * 0.5d ) / (0.5d * 0.5d), tol);
dist = new PascalDistribution(25, 0.7);
Assert.assertEquals(dist.getNumericalMean(), ( 25d * 0.3d ) / 0.7d, tol);
Assert.assertEquals(dist.getNumericalVariance(), ( 25d * 0.3d ) / (0.7d * 0.7d), tol);
}
}