eu.crisis_economics.abm.algorithms.series.TestAbstractSeries.java Source code

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Here is the source code for eu.crisis_economics.abm.algorithms.series.TestAbstractSeries.java

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/*
 * This file is part of CRISIS, an economics simulator.
 * 
 * Copyright (C) 2015 John Kieran Phillips
 *
 * CRISIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * CRISIS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with CRISIS.  If not, see <http://www.gnu.org/licenses/>.
 */
package eu.crisis_economics.abm.algorithms.series;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.math3.stat.descriptive.moment.Mean;
import org.apache.commons.math3.stat.descriptive.moment.StandardDeviation;
import org.testng.Assert;

/**
  * A base class for {@link RandomSeries} unit tests.
  * 
  * @author phillips
  */
abstract class TestAbstractSeries {

    /**
      * Assert that:
      * 
      * <ul>
      *   <li> The long term observed mean for the {@link RandomSeries} in the first
      *        argument is as expected.
      *   <li> The long term standard deviation for the {@link RandomSeries} in the first
      *        argument is as expected.
      * </ul>
      * 
      * @param series (<code>S</code>) <br>
      *        The {@link RandomSeries} object to test.
      * @param numberOfSamples <br>
      *        The number of samples to draw from <code>S</code>.
      * @param expectedLongTermMean <br>
      *        The expected long term mean of the series.
      * @param expectedLongTermStd <br>
      *        The expected long term standard deviation of the series.
      * @param expectedInitialValue <br>
      *        The initial value of the series.
      */
    protected void assertLongTermMomentsAndInitialValue(RandomSeries series, final int numberOfSamples,
            final double expectedLongTermMean, final double expectedLongTermStd,
            final double expectedInitialValue) {
        assertInitialValue(series, expectedInitialValue);
        assertLongTermMean(series, numberOfSamples, expectedLongTermMean);
        assertLongTermStd(series, numberOfSamples, expectedLongTermStd);
    }

    /**
      * Assert that the initial value drawn from a {@link RandomSeries} object
      * is as expected.
      * 
      * @param series <br>
      *        The {@link RandomSeries} from which to draw the initial value.
      * @param expectedInitialValue <br>
      *        The expected initial value to draw.
      */
    protected void assertInitialValue(RandomSeries series, final double expectedInitialValue) {
        Assert.assertEquals(series.next(), expectedInitialValue, 1.e-14);
    }

    /**
      * Assert that the long term mean of values drawn from a {@link RandomSeries} object
      * is as expected.
      * 
      * @param series (<code>S</code>) <br>
      *        The {@link RandomSeries} object to test.
      * @param numberOfSamples <br>
      *        The number of samples to draw from <code>S</code>.
      * @param expectedLongTermMean <br>
      *        The expected long term mean of the series.
      */
    protected void assertLongTermMean(RandomSeries series, final int numberOfSamples,
            final double expectedLongTermMean) {
        final Mean mean = new Mean();

        for (int i = 0; i < numberOfSamples; ++i)
            mean.increment(series.next());

        Assert.assertEquals(mean.getResult(), expectedLongTermMean, 1.e-2);
    }

    /**
      * Assert that the long term mean of values drawn from a {@link RandomSeries} object
      * is as expected.
      * 
      * @param series (<code>S</code>) <br>
      *        The {@link RandomSeries} object to test.
      * @param numberOfSamples <br>
      *        The number of samples to draw from <code>S</code>.
      * @param expectedLongTermStd <br>
      *        The expected long term standard deviation of the series.
      */
    protected void assertLongTermStd(RandomSeries series, final int numberOfSamples,
            final double expectedLongTermStd) {
        final List<Double> observations = new ArrayList<Double>();

        for (int i = 0; i < numberOfSamples; ++i)
            observations.add(series.next());

        final double observedMean = (new StandardDeviation())
                .evaluate(ArrayUtils.toPrimitive(observations.toArray(new Double[observations.size()])));

        Assert.assertEquals(observedMean, expectedLongTermStd, 1.e-1);
    }

    protected static interface RandomSeriesFactory {
        RandomSeries createFactory(long seed);
    }

    /**
      * Assert that two {@link RandomSeries} objects created with the same seed have
      * the same output series (for <code>1000</code> samples).
      * 
      * @param factory
      *        A {@link RandomSeriesFactory} object which creates an instance of a
      *        {@link RandomSeries} from a seed {@link Long}.
      */
    protected void assertReproducibility(final RandomSeriesFactory factory) {
        final RandomSeries first = factory.createFactory(123L), second = factory.createFactory(123L);
        for (int i = 0; i < 1000; ++i)
            Assert.assertEquals(first.next(), second.next(), 0.);
    }
}