home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (BinomialDistributionTest.java)

This example Java source code file (BinomialDistributionTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

binomialdistribution, binomialdistributiontest, integerdistribution, integerdistributionabstracttest, override, test

The BinomialDistributionTest.java Java example source code

/*
 * 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.math3.distribution;

import org.junit.Assert;
import org.junit.Test;

/**
 * Test cases for BinomialDistribution. Extends IntegerDistributionAbstractTest.
 * See class javadoc for IntegerDistributionAbstractTest for details.
 *
 */
public class BinomialDistributionTest extends IntegerDistributionAbstractTest {

    /**
     * Constructor to override default tolerance.
     */
    public BinomialDistributionTest() {
        setTolerance(1e-12);
    }

    // -------------- Implementations for abstract methods
    // -----------------------

    /** Creates the default discrete distribution instance to use in tests. */
    @Override
    public IntegerDistribution makeDistribution() {
        return new BinomialDistribution(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.
     * Reference values are from R, version 2.15.3.
     */
    @Override
    public double[] makeDensityTestValues() {
        return new double[] { 0d, 0.0000059049d, 0.000137781d, 0.0014467005,
            0.009001692, 0.036756909, 0.1029193452, 0.200120949, 0.266827932,
            0.2334744405, 0.121060821, 0.0282475249, 0d };
    }

    /** Creates the default cumulative probability density test input values */
    @Override
    public int[] makeCumulativeTestPoints() {
        return makeDensityTestPoints();
    }

    /**
     * Creates the default cumulative probability density test expected values.
     * Reference values are from R, version 2.15.3.
     */
    @Override
    public double[] makeCumulativeTestValues() {
        return new double[] { 0d, 5.9049e-06, 0.0001436859, 0.0015903864, 0.0105920784,  0.0473489874,
            0.1502683326, 0.3503892816, 0.6172172136, 0.8506916541, 0.9717524751, 1d, 1d };
    }

    /** Creates the default inverse cumulative probability test input values */
    @Override
    public double[] makeInverseCumulativeTestPoints() {
        return new double[] { 0, 0.001d, 0.010d, 0.025d, 0.050d, 0.100d,
                0.999d, 0.990d, 0.975d, 0.950d, 0.900d, 1 };
    }

    /**
     * Creates the default inverse cumulative probability density test expected
     * values
     */
    @Override
    public int[] makeInverseCumulativeTestValues() {
        return new int[] { 0, 2, 3, 4, 5, 5, 10, 10, 10, 9, 9, 10 };
    }

    // ----------------- Additional test cases ---------------------------------

    /** Test degenerate case p = 0 */
    @Test
    public void testDegenerate0() {
        BinomialDistribution dist = new BinomialDistribution(5, 0.0d);
        setDistribution(dist);
        setCumulativeTestPoints(new int[] { -1, 0, 1, 5, 10 });
        setCumulativeTestValues(new double[] { 0d, 1d, 1d, 1d, 1d });
        setDensityTestPoints(new int[] { -1, 0, 1, 10, 11 });
        setDensityTestValues(new double[] { 0d, 1d, 0d, 0d, 0d });
        setInverseCumulativeTestPoints(new double[] { 0.1d, 0.5d });
        setInverseCumulativeTestValues(new int[] { 0, 0 });
        verifyDensities();
        verifyCumulativeProbabilities();
        verifyInverseCumulativeProbabilities();
        Assert.assertEquals(dist.getSupportLowerBound(), 0);
        Assert.assertEquals(dist.getSupportUpperBound(), 0);
    }

    /** Test degenerate case p = 1 */
    @Test
    public void testDegenerate1() {
        BinomialDistribution dist = new BinomialDistribution(5, 1.0d);
        setDistribution(dist);
        setCumulativeTestPoints(new int[] { -1, 0, 1, 2, 5, 10 });
        setCumulativeTestValues(new double[] { 0d, 0d, 0d, 0d, 1d, 1d });
        setDensityTestPoints(new int[] { -1, 0, 1, 2, 5, 10 });
        setDensityTestValues(new double[] { 0d, 0d, 0d, 0d, 1d, 0d });
        setInverseCumulativeTestPoints(new double[] { 0.1d, 0.5d });
        setInverseCumulativeTestValues(new int[] { 5, 5 });
        verifyDensities();
        verifyCumulativeProbabilities();
        verifyInverseCumulativeProbabilities();
        Assert.assertEquals(dist.getSupportLowerBound(), 5);
        Assert.assertEquals(dist.getSupportUpperBound(), 5);
    }

    /** Test degenerate case n = 0 */
    @Test
    public void testDegenerate2() {
        BinomialDistribution dist = new BinomialDistribution(0, 0.01d);
        setDistribution(dist);
        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();
        Assert.assertEquals(dist.getSupportLowerBound(), 0);
        Assert.assertEquals(dist.getSupportUpperBound(), 0);
    }

    @Test
    public void testMoments() {
        final double tol = 1e-9;
        BinomialDistribution dist;

        dist = new BinomialDistribution(10, 0.5);
        Assert.assertEquals(dist.getNumericalMean(), 10d * 0.5d, tol);
        Assert.assertEquals(dist.getNumericalVariance(), 10d * 0.5d * 0.5d, tol);

        dist = new BinomialDistribution(30, 0.3);
        Assert.assertEquals(dist.getNumericalMean(), 30d * 0.3d, tol);
        Assert.assertEquals(dist.getNumericalVariance(), 30d * 0.3d * (1d - 0.3d), tol);
    }

    @Test
    public void testMath718() {
        // for large trials the evaluation of ContinuedFraction was inaccurate
        // do a sweep over several large trials to test if the current implementation is
        // numerically stable.

        for (int trials = 500000; trials < 20000000; trials += 100000) {
            BinomialDistribution dist = new BinomialDistribution(trials, 0.5);
            int p = dist.inverseCumulativeProbability(0.5);
            Assert.assertEquals(trials / 2, p);
        }
    }
}

Other Java examples (source code examples)

Here is a short list of links related to this Java BinomialDistributionTest.java source code file:



my book on functional programming

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.