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* 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,
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* See the License for the specific language governing permissions and
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package org.apache.commons.math.ode.nonstiff;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Random;
import org.apache.commons.math.ode.ContinuousOutputModel;
import org.apache.commons.math.ode.DerivativeException;
import org.apache.commons.math.ode.IntegratorException;
import org.apache.commons.math.ode.TestProblem3;
import org.apache.commons.math.ode.sampling.StepHandler;
import org.apache.commons.math.ode.sampling.StepInterpolator;
import org.apache.commons.math.ode.sampling.StepInterpolatorTestUtils;
import org.junit.Test;
public class GraggBulirschStoerStepInterpolatorTest {
@Test
public void derivativesConsistency()
throws DerivativeException, IntegratorException {
TestProblem3 pb = new TestProblem3(0.9);
double minStep = 0;
double maxStep = pb.getFinalTime() - pb.getInitialTime();
double absTolerance = 1.0e-8;
double relTolerance = 1.0e-8;
GraggBulirschStoerIntegrator integ =
new GraggBulirschStoerIntegrator(minStep, maxStep,
absTolerance, relTolerance);
StepInterpolatorTestUtils.checkDerivativesConsistency(integ, pb, 1.0e-8);
}
@Test
public void serialization()
throws DerivativeException, IntegratorException,
IOException, ClassNotFoundException {
TestProblem3 pb = new TestProblem3(0.9);
double minStep = 0;
double maxStep = pb.getFinalTime() - pb.getInitialTime();
double absTolerance = 1.0e-8;
double relTolerance = 1.0e-8;
GraggBulirschStoerIntegrator integ =
new GraggBulirschStoerIntegrator(minStep, maxStep,
absTolerance, relTolerance);
integ.addStepHandler(new ContinuousOutputModel());
integ.integrate(pb,
pb.getInitialTime(), pb.getInitialState(),
pb.getFinalTime(), new double[pb.getDimension()]);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(bos);
for (StepHandler handler : integ.getStepHandlers()) {
oos.writeObject(handler);
}
assertTrue(bos.size () > 33000);
assertTrue(bos.size () < 34000);
ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
ObjectInputStream ois = new ObjectInputStream(bis);
ContinuousOutputModel cm = (ContinuousOutputModel) ois.readObject();
Random random = new Random(347588535632l);
double maxError = 0.0;
for (int i = 0; i < 1000; ++i) {
double r = random.nextDouble();
double time = r * pb.getInitialTime() + (1.0 - r) * pb.getFinalTime();
cm.setInterpolatedTime(time);
double[] interpolatedY = cm.getInterpolatedState ();
double[] theoreticalY = pb.computeTheoreticalState(time);
double dx = interpolatedY[0] - theoreticalY[0];
double dy = interpolatedY[1] - theoreticalY[1];
double error = dx * dx + dy * dy;
if (error > maxError) {
maxError = error;
}
}
assertTrue(maxError < 5.0e-10);
}
@Test
public void checklone()
throws DerivativeException, IntegratorException {
TestProblem3 pb = new TestProblem3(0.9);
double minStep = 0;
double maxStep = pb.getFinalTime() - pb.getInitialTime();
double scalAbsoluteTolerance = 1.0e-8;
double scalRelativeTolerance = scalAbsoluteTolerance;
GraggBulirschStoerIntegrator integ = new GraggBulirschStoerIntegrator(minStep, maxStep,
scalAbsoluteTolerance,
scalRelativeTolerance);
integ.addStepHandler(new StepHandler() {
public void handleStep(StepInterpolator interpolator, boolean isLast)
throws DerivativeException {
StepInterpolator cloned = interpolator.copy();
double tA = cloned.getPreviousTime();
double tB = cloned.getCurrentTime();
double halfStep = Math.abs(tB - tA) / 2;
assertEquals(interpolator.getPreviousTime(), tA, 1.0e-12);
assertEquals(interpolator.getCurrentTime(), tB, 1.0e-12);
for (int i = 0; i < 10; ++i) {
double t = (i * tB + (9 - i) * tA) / 9;
interpolator.setInterpolatedTime(t);
assertTrue(Math.abs(cloned.getInterpolatedTime() - t) > (halfStep / 10));
cloned.setInterpolatedTime(t);
assertEquals(t, cloned.getInterpolatedTime(), 1.0e-12);
double[] referenceState = interpolator.getInterpolatedState();
double[] cloneState = cloned.getInterpolatedState();
for (int j = 0; j < referenceState.length; ++j) {
assertEquals(referenceState[j], cloneState[j], 1.0e-12);
}
}
}
public boolean requiresDenseOutput() {
return true;
}
public void reset() {
}
});
integ.integrate(pb,
pb.getInitialTime(), pb.getInitialState(),
pb.getFinalTime(), new double[pb.getDimension()]);
}
}