/**
* Copyright (C) 2009 - present by OpenGamma Inc. and the OpenGamma group of companies
*
* Please see distribution for license.
*/
package com.opengamma.analytics.financial.timeseries.model;
import static org.testng.AssertJUnit.assertEquals;
import static org.testng.AssertJUnit.assertTrue;
import org.testng.annotations.Test;
import org.threeten.bp.LocalDate;
import cern.jet.random.engine.MersenneTwister;
import cern.jet.random.engine.MersenneTwister64;
import com.opengamma.analytics.financial.timeseries.analysis.AutocorrelationFunctionCalculator;
import com.opengamma.analytics.financial.timeseries.analysis.DoubleTimeSeriesStatisticsCalculator;
import com.opengamma.analytics.math.statistics.descriptive.MeanCalculator;
import com.opengamma.analytics.math.statistics.descriptive.SampleVarianceCalculator;
import com.opengamma.analytics.math.statistics.distribution.NormalDistribution;
import com.opengamma.timeseries.date.localdate.LocalDateDoubleTimeSeries;
import com.opengamma.util.test.TestGroup;
/**
* Test.
*/
@Test(groups = TestGroup.UNIT)
public class MovingAverageTimeSeriesModelTest {
private static final double MEAN = 0;
private static final double STD = 0.25;
private static final MovingAverageTimeSeriesModel MODEL = new MovingAverageTimeSeriesModel(new NormalDistribution(MEAN, STD,
new MersenneTwister64(MersenneTwister.DEFAULT_SEED)));
private static final int ORDER = 2;
private static final LocalDateDoubleTimeSeries MA;
private static final double[] THETA;
private static double LIMIT = 3;
static {
final int n = 20000;
final LocalDate[] dates = new LocalDate[n];
for (int i = 0; i < n; i++) {
dates[i] = LocalDate.ofEpochDay(i);
}
THETA = new double[ORDER + 1];
THETA[0] = 0.;
for (int i = 1; i <= ORDER; i++) {
THETA[i] = (i + 1) / 10.;
}
MA = MODEL.getSeries(THETA, ORDER, dates);
LIMIT /= Math.sqrt(n);
}
@Test(expectedExceptions = IllegalArgumentException.class)
public void testBadConstructor() {
new MovingAverageTimeSeriesModel(null);
}
@Test(expectedExceptions = IllegalArgumentException.class)
public void testNullThetas() {
MODEL.getSeries(null, 2, new LocalDate[] {LocalDate.ofEpochDay(1)});
}
@Test(expectedExceptions = IllegalArgumentException.class)
public void testEmptyThetas() {
MODEL.getSeries(new double[0], 2, new LocalDate[] {LocalDate.ofEpochDay(1)});
}
@Test(expectedExceptions = IllegalArgumentException.class)
public void testNegativeOrder() {
MODEL.getSeries(new double[] {0.2}, -3, new LocalDate[] {LocalDate.ofEpochDay(1)});
}
@Test(expectedExceptions = IllegalArgumentException.class)
public void testInsufficientThetas() {
MODEL.getSeries(new double[] {0.2}, 4, new LocalDate[] {LocalDate.ofEpochDay(1)});
}
@Test(expectedExceptions = IllegalArgumentException.class)
public void testNullDates() {
MODEL.getSeries(new double[] {0.3}, 1, null);
}
@Test(expectedExceptions = IllegalArgumentException.class)
public void testEmptyDates() {
MODEL.getSeries(new double[] {0.3}, 1, new LocalDate[0]);
}
@Test
public void testACF() {
final double eps = 1e-2;
final double[] rho = new AutocorrelationFunctionCalculator().evaluate(MA);
assertEquals(rho[0], 1, 1e-16);
final double denom = 1 + THETA[1] * THETA[1] + THETA[2] * THETA[2];
assertEquals(rho[1], (THETA[1] * THETA[2] + THETA[1]) / denom, eps);
assertEquals(rho[2], THETA[2] / denom, eps);
for (int i = 1; i <= 20; i++) {
if (i < ORDER + 1) {
assertTrue(rho[i] > LIMIT);
} else {
assertTrue(rho[i] < LIMIT);
}
}
final Double mean = new DoubleTimeSeriesStatisticsCalculator(new MeanCalculator()).evaluate(MA);
assertEquals(mean, THETA[0], eps);
final Double variance = new DoubleTimeSeriesStatisticsCalculator(new SampleVarianceCalculator()).evaluate(MA);
double sum = 1;
for (int i = 1; i <= ORDER; i++) {
sum += THETA[i] * THETA[i];
}
assertEquals(variance, sum * STD * STD, eps);
}
}