jidt/java/unittests/infodynamics/measures/continuous/gaussian/EntropyCalculatorGaussianTe...

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Java
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/*
* Java Information Dynamics Toolkit (JIDT)
* Copyright (C) 2012, Joseph T. Lizier
*
* This program 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
package infodynamics.measures.continuous.gaussian;
import infodynamics.utils.MatrixUtils;
import infodynamics.utils.RandomGenerator;
import junit.framework.TestCase;
public class EntropyCalculatorGaussianTest extends TestCase {
public void testVarianceSetting() throws Exception {
EntropyCalculatorGaussian entcalc = new EntropyCalculatorGaussian();
entcalc.initialise();
double variance = 3.45567;
entcalc.setVariance(variance);
assertEquals(variance, entcalc.variance);
}
public void testVarianceCalculation() {
EntropyCalculatorGaussian entcalc = new EntropyCalculatorGaussian();
entcalc.initialise();
RandomGenerator randomGenerator = new RandomGenerator();
double[] gaussianObservations = randomGenerator.generateNormalData(100, 5, 3);
double variance = MatrixUtils.stdDev(gaussianObservations);
variance *= variance;
entcalc.setObservations(gaussianObservations);
assertEquals(variance, entcalc.variance);
}
public void testEntropyCalculation() throws Exception {
EntropyCalculatorGaussian entcalc = new EntropyCalculatorGaussian();
entcalc.initialise();
double variance = 3.45567;
entcalc.setVariance(variance);
double expectedEntropy = 0.5 * Math.log(2.0*Math.PI*Math.E*variance);
assertEquals(expectedEntropy, entcalc.computeAverageLocalOfObservations());
}
public void testLocalEntropiesAverage() throws Exception {
RandomGenerator rg = new RandomGenerator();
double[] data = rg.generateNormalData(100, 0, 1);
EntropyCalculatorGaussian entcalc = new EntropyCalculatorGaussian();
entcalc.initialise();
entcalc.setObservations(data);
double entropy = entcalc.computeAverageLocalOfObservations();
double[] localEntropies = entcalc.computeLocalOfPreviousObservations();
double avgLocal = MatrixUtils.mean(localEntropies);
// There are many sources of numerical noise in the combination of so many
// local entropy calculations here (in comparison to the average calculation
// which only comes from the variance), so we need to leave a wide tolerance
assertEquals(entropy, avgLocal, 0.02);
}
}