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Commons Math example source code file (BetaDistributionTest.java)

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

Java - Commons Math tags/keywords

betadistribution, betadistribution, betadistributionimpl, betadistributionimpl, betadistributiontest, mathexception, mathexception, testcase, testcase

The Commons Math BetaDistributionTest.java 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.math.distribution;

import junit.framework.TestCase;
import org.apache.commons.math.MathException;

public class BetaDistributionTest extends TestCase {
    public void testCumulative() throws MathException {
        double[] x = new double[]{-0.1, 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1};
        // all test data computed using R 2.5
        checkCumulative(0.1, 0.1,
                x, new double[]{
                0.0000000000, 0.0000000000, 0.4063850939, 0.4397091902, 0.4628041861,
                0.4821200456, 0.5000000000, 0.5178799544, 0.5371958139, 0.5602908098,
                0.5936149061, 1.0000000000, 1.0000000000});
        checkCumulative(0.1, 0.5,
                x, new double[]{
                0.0000000000, 0.0000000000, 0.7048336221, 0.7593042194, 0.7951765304,
                0.8234948385, 0.8480017124, 0.8706034370, 0.8926585878, 0.9156406404,
                0.9423662883, 1.0000000000, 1.0000000000});
        checkCumulative(0.1, 1.0,
                x, new double[]{
                0.0000000000, 0.0000000000, 0.7943282347, 0.8513399225, 0.8865681506,
                0.9124435366, 0.9330329915, 0.9502002165, 0.9649610951, 0.9779327685,
                0.9895192582, 1.0000000000, 1.0000000000});
        checkCumulative(0.1, 2.0,
                x, new double[]{
                0.0000000000, 0.0000000000, 0.8658177758, 0.9194471163, 0.9486279211,
                0.9671901487, 0.9796846411, 0.9882082252, 0.9939099280, 0.9974914239,
                0.9994144508, 1.0000000000, 1.0000000000});
        checkCumulative(0.1, 4.0,
                x, new double[]{
                0.0000000000, 0.0000000000, 0.9234991121, 0.9661958941, 0.9842285085,
                0.9928444112, 0.9970040660, 0.9989112804, 0.9996895625, 0.9999440793,
                0.9999967829, 1.0000000000, 1.0000000000});
        checkCumulative(0.5, 0.1,
                x, new double[]{
                0.00000000000, 0.00000000000, 0.05763371168, 0.08435935962,
                0.10734141216, 0.12939656302, 0.15199828760, 0.17650516146,
                0.20482346963, 0.24069578055, 0.29516637795, 1.00000000000, 1.00000000000});

        checkCumulative(0.5, 0.5,
                x, new double[]{
                0.0000000000, 0.0000000000, 0.2048327647, 0.2951672353, 0.3690101196,
                0.4359057832, 0.5000000000, 0.5640942168, 0.6309898804, 0.7048327647,
                0.7951672353, 1.0000000000, 1.0000000000});
        checkCumulative(0.5, 1.0,
                x, new double[]{
                0.0000000000, 0.0000000000, 0.3162277660, 0.4472135955, 0.5477225575,
                0.6324555320, 0.7071067812, 0.7745966692, 0.8366600265, 0.8944271910,
                0.9486832981, 1.0000000000, 1.0000000000});
        checkCumulative(0.5, 2.0,
                x, new double[]{
                0.0000000000, 0.0000000000, 0.4585302607, 0.6260990337, 0.7394254526,
                0.8221921916, 0.8838834765, 0.9295160031, 0.9621590305, 0.9838699101,
                0.9961174630, 1.0000000000, 1.0000000000});
        checkCumulative(0.5, 4.0,
                x, new double[]{
                0.0000000000, 0.0000000000, 0.6266250826, 0.8049844719, 0.8987784842,
                0.9502644369, 0.9777960959, 0.9914837366, 0.9974556254, 0.9995223859,
                0.9999714889, 1.0000000000, 1.0000000000});
        checkCumulative(1.0, 0.1,
                x, new double[]{
                0.00000000000, 0.00000000000, 0.01048074179, 0.02206723146,
                0.03503890488, 0.04979978349, 0.06696700846, 0.08755646344,
                0.11343184943, 0.14866007748, 0.20567176528, 1.00000000000, 1.00000000000});
        checkCumulative(1.0, 0.5,
                x, new double[]{
                0.00000000000, 0.00000000000, 0.05131670195, 0.10557280900,
                0.16333997347, 0.22540333076, 0.29289321881, 0.36754446797,
                0.45227744249, 0.55278640450, 0.68377223398, 1.00000000000, 1.00000000000});
        checkCumulative(1, 1,
                x, new double[]{
                0.0, 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.0});
        checkCumulative(1, 2,
                x, new double[]{
                0.00, 0.00, 0.19, 0.36, 0.51, 0.64, 0.75, 0.84, 0.91, 0.96, 0.99, 1.00, 1.00});
        checkCumulative(1, 4,
                x, new double[]{
                0.0000, 0.0000, 0.3439, 0.5904, 0.7599, 0.8704, 0.9375, 0.9744, 0.9919,
                0.9984, 0.9999, 1.0000, 1.0000});
        checkCumulative(2.0, 0.1,
                x, new double[]{
                0.0000000000000, 0.0000000000000, 0.0005855492117, 0.0025085760862,
                0.0060900720266, 0.0117917748341, 0.0203153588864, 0.0328098512512,
                0.0513720788952, 0.0805528836776, 0.1341822241505, 1.0000000000000, 1.0000000000000});
        checkCumulative(2, 1,
                x, new double[]{
                0.00, 0.00, 0.01, 0.04, 0.09, 0.16, 0.25, 0.36, 0.49, 0.64, 0.81, 1.00, 1.00});
        checkCumulative(2.0, 0.5,
                x, new double[]{
                0.000000000000, 0.000000000000, 0.003882537047, 0.016130089900,
                0.037840969486, 0.070483996910, 0.116116523517, 0.177807808356,
                0.260574547368, 0.373900966300, 0.541469739276, 1.000000000000, 1.000000000000});
        checkCumulative(2, 2,
                x, new double[]{
                0.000, 0.000, 0.028, 0.104, 0.216, 0.352, 0.500, 0.648, 0.784, 0.896, 0.972, 1.000, 1.000});
        checkCumulative(2, 4,
                x, new double[]{
                0.00000, 0.00000, 0.08146, 0.26272, 0.47178, 0.66304, 0.81250, 0.91296,
                0.96922, 0.99328, 0.99954, 1.00000, 1.00000});
        checkCumulative(4.0, 0.1,
                x, new double[]{
                0.000000000e+00, 0.000000000e+00, 3.217128269e-06, 5.592070271e-05,
                3.104375474e-04, 1.088719595e-03, 2.995933981e-03, 7.155588777e-03,
                1.577149153e-02, 3.380410585e-02, 7.650088789e-02, 1.000000000e+00, 1.000000000e+00});
        checkCumulative(4.0, 0.5,
                x, new double[]{
                0.000000000e+00, 0.000000000e+00, 2.851114863e-05, 4.776140576e-04,
                2.544374616e-03, 8.516263371e-03, 2.220390414e-02, 4.973556312e-02,
                1.012215158e-01, 1.950155281e-01, 3.733749174e-01, 1.000000000e+00, 1.000000000e+00});
        checkCumulative(4, 1,
                x, new double[]{
                0.0000, 0.0000, 0.0001, 0.0016, 0.0081, 0.0256, 0.0625, 0.1296, 0.2401,
                0.4096, 0.6561, 1.0000, 1.0000});
        checkCumulative(4, 2,
                x, new double[]{
                0.00000, 0.00000, 0.00046, 0.00672, 0.03078, 0.08704, 0.18750, 0.33696,
                0.52822, 0.73728, 0.91854, 1.00000, 1.00000});
        checkCumulative(4, 4,
                x, new double[]{
                0.000000, 0.000000, 0.002728, 0.033344, 0.126036, 0.289792, 0.500000,
                0.710208, 0.873964, 0.966656, 0.997272, 1.000000, 1.000000});

    }

    private void checkCumulative(double alpha, double beta, double[] x, double[] cumes) throws MathException {
        BetaDistribution d = new BetaDistributionImpl(alpha, beta);
        for (int i = 0; i < x.length; i++) {
            assertEquals(cumes[i], d.cumulativeProbability(x[i]), 1e-8);
        }

        for (int i = 1; i < x.length - 1; i++) {
            assertEquals(x[i], d.inverseCumulativeProbability(cumes[i]), 1e-5);
        }
    }

    public void testDensity() throws MathException {
        double[] x = new double[]{1e-6, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9};
        checkDensity(0.1, 0.1,
                x, new double[]{
                12741.2357380649, 0.4429889586665234, 2.639378715e-01, 2.066393611e-01,
                1.832401831e-01, 1.766302780e-01, 1.832404579e-01, 2.066400696e-01,
                2.639396531e-01, 4.429925026e-01});
        checkDensity(0.1, 0.5,
                x, new double[]{
                2.218377102e+04, 7.394524202e-01, 4.203020268e-01, 3.119435533e-01,
                2.600787829e-01, 2.330648626e-01, 2.211408259e-01, 2.222728708e-01,
                2.414013907e-01, 3.070567405e-01});
        checkDensity(0.1, 1.0,
                x, new double[]{
                2.511886432e+04, 7.943210858e-01, 4.256680458e-01, 2.955218303e-01,
                2.281103709e-01, 1.866062624e-01, 1.583664652e-01, 1.378514078e-01,
                1.222414585e-01, 1.099464743e-01});
        checkDensity(0.1, 2.0,
                x, new double[]{
                2.763072312e+04, 7.863770012e-01, 3.745874120e-01, 2.275514842e-01,
                1.505525939e-01, 1.026332391e-01, 6.968107049e-02, 4.549081293e-02,
                2.689298641e-02, 1.209399123e-02});
        checkDensity(0.1, 4.0,
                x, new double[]{
                2.997927462e+04, 6.911058917e-01, 2.601128486e-01, 1.209774010e-01,
                5.880564714e-02, 2.783915474e-02, 1.209657335e-02, 4.442148268e-03,
                1.167143939e-03, 1.312171805e-04});
        checkDensity(0.5, 0.1,
                x, new double[]{
                88.3152184726, 0.3070542841, 0.2414007269, 0.2222727015,
                0.2211409364, 0.2330652355, 0.2600795198, 0.3119449793,
                0.4203052841, 0.7394649088});
        checkDensity(0.5, 0.5,
                x, new double[]{
                318.3100453389, 1.0610282383, 0.7957732234, 0.6946084565,
                0.6497470636, 0.6366197724, 0.6497476051, 0.6946097796,
                0.7957762075, 1.0610376697});
        checkDensity(0.5, 1.0,
                x, new double[]{
                500.0000000000, 1.5811309244, 1.1180311937, 0.9128694077,
                0.7905684268, 0.7071060741, 0.6454966865, 0.5976138778,
                0.5590166450, 0.5270459839});
        checkDensity(0.5, 2.0,
                x, new double[]{
                749.99925000000, 2.134537420613655, 1.34163575536, 0.95851150881,
                0.71151039830, 0.53032849490, 0.38729704363, 0.26892534859,
                0.16770415497, 0.07905610701});
        checkDensity(0.5, 4.0,
                x, new double[]{
                1.093746719e+03, 2.52142232809988, 1.252190241e+00, 6.849343920e-01,
                3.735417140e-01, 1.933481570e-01, 9.036885833e-02, 3.529621669e-02,
                9.782644546e-03, 1.152878503e-03});
        checkDensity(1.0, 0.1,
                x, new double[]{
                0.1000000900, 0.1099466942, 0.1222417336, 0.1378517623, 0.1583669403,
                0.1866069342, 0.2281113974, 0.2955236034, 0.4256718768,
                0.7943353837});
        checkDensity(1.0, 0.5,
                x, new double[]{
                0.5000002500, 0.5270465695, 0.5590173438, 0.5976147315, 0.6454977623,
                0.7071074883, 0.7905704033, 0.9128724506,
                1.1180367838, 1.5811467358});
        checkDensity(1, 1,
                x, new double[]{
                1, 1, 1,
                1, 1, 1, 1,
                1, 1, 1});
        checkDensity(1, 2,
                x, new double[]{
                1.999998, 1.799998, 1.599998, 1.399998, 1.199998, 0.999998, 0.799998,
                0.599998, 0.399998,
                0.199998});
        checkDensity(1, 4,
                x, new double[]{
                3.999988000012, 2.915990280011, 2.047992320010, 1.371994120008,
                0.863995680007, 0.499997000006, 0.255998080005, 0.107998920004,
                0.031999520002, 0.003999880001});
        checkDensity(2.0, 0.1,
                x, new double[]{
                1.100000990e-07, 1.209425730e-02, 2.689331586e-02, 4.549123318e-02,
                6.968162794e-02, 1.026340191e-01, 1.505537732e-01, 2.275534997e-01,
                3.745917198e-01, 7.863929037e-01});
        checkDensity(2.0, 0.5,
                x, new double[]{
                7.500003750e-07, 7.905777599e-02, 1.677060417e-01, 2.689275256e-01,
                3.872996256e-01, 5.303316769e-01, 7.115145488e-01, 9.585174425e-01,
                1.341645818e+00, 2.134537420613655});
        checkDensity(2, 1,
                x, new double[]{
                0.000002, 0.200002, 0.400002, 0.600002, 0.800002, 1.000002, 1.200002,
                1.400002, 1.600002,
                1.800002});
        checkDensity(2, 2,
                x, new double[]{
                5.9999940e-06, 5.4000480e-01, 9.6000360e-01, 1.2600024e+00,
                1.4400012e+00, 1.5000000e+00, 1.4399988e+00, 1.2599976e+00,
                9.5999640e-01, 5.3999520e-01});
        checkDensity(2, 4,
                x, new double[]{
                0.00001999994, 1.45800971996, 2.04800255997, 2.05799803998,
                1.72799567999, 1.24999500000, 0.76799552000, 0.37799676001,
                0.12799824001, 0.01799948000});
        checkDensity(4.0, 0.1,
                x, new double[]{
                1.193501074e-19, 1.312253162e-04, 1.167181580e-03, 4.442248535e-03,
                1.209679109e-02, 2.783958903e-02, 5.880649983e-02, 1.209791638e-01,
                2.601171405e-01, 6.911229392e-01});
        checkDensity(4.0, 0.5,
                x, new double[]{
                1.093750547e-18, 1.152948959e-03, 9.782950259e-03, 3.529697305e-02,
                9.037036449e-02, 1.933508639e-01, 3.735463833e-01, 6.849425461e-01,
                1.252205894e+00, 2.52142232809988});
        checkDensity(4, 1,
                x, new double[]{
                4.000000000e-18, 4.000120001e-03, 3.200048000e-02, 1.080010800e-01,
                2.560019200e-01, 5.000030000e-01, 8.640043200e-01, 1.372005880e+00,
                2.048007680e+00, 2.916009720e+00});
        checkDensity(4, 2,
                x, new double[]{
                1.999998000e-17, 1.800052000e-02, 1.280017600e-01, 3.780032400e-01,
                7.680044800e-01, 1.250005000e+00, 1.728004320e+00, 2.058001960e+00,
                2.047997440e+00, 1.457990280e+00});
        checkDensity(4, 4,
                x, new double[]{
                1.399995800e-16, 1.020627216e-01, 5.734464512e-01, 1.296547409e+00,
                1.935364838e+00, 2.187500000e+00, 1.935355162e+00, 1.296532591e+00,
                5.734335488e-01, 1.020572784e-01});

    }

    private void checkDensity(double alpha, double beta, double[] x, double[] expected) throws MathException {
        BetaDistribution d = new BetaDistributionImpl(alpha, beta);
        for (int i = 0; i < x.length; i++) {
            assertEquals(String.format("density at x=%.1f for alpha=%.1f, beta=%.1f", x[i], alpha, beta), expected[i], d.density(x[i]), 1e-5);
        }
    }
}

Other Commons Math examples (source code examples)

Here is a short list of links related to this Commons Math BetaDistributionTest.java source code file:

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