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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
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* 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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package org.apache.commons.math.ode.nonstiff;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import org.apache.commons.math.ode.DerivativeException;
import org.apache.commons.math.ode.FirstOrderIntegrator;
import org.apache.commons.math.ode.IntegratorException;
import org.apache.commons.math.ode.TestProblem1;
import org.apache.commons.math.ode.TestProblem5;
import org.apache.commons.math.ode.TestProblem6;
import org.apache.commons.math.ode.TestProblemHandler;
import org.junit.Test;
public class AdamsMoultonIntegratorTest {
@Test(expected=IntegratorException.class)
public void dimensionCheck() throws DerivativeException, IntegratorException {
TestProblem1 pb = new TestProblem1();
FirstOrderIntegrator integ =
new AdamsMoultonIntegrator(2, 0.0, 1.0, 1.0e-10, 1.0e-10);
integ.integrate(pb,
0.0, new double[pb.getDimension()+10],
1.0, new double[pb.getDimension()+10]);
}
@Test(expected=IntegratorException.class)
public void testMinStep() throws DerivativeException, IntegratorException {
TestProblem1 pb = new TestProblem1();
double minStep = 0.1 * (pb.getFinalTime() - pb.getInitialTime());
double maxStep = pb.getFinalTime() - pb.getInitialTime();
double[] vecAbsoluteTolerance = { 1.0e-15, 1.0e-16 };
double[] vecRelativeTolerance = { 1.0e-15, 1.0e-16 };
FirstOrderIntegrator integ = new AdamsMoultonIntegrator(4, minStep, maxStep,
vecAbsoluteTolerance,
vecRelativeTolerance);
TestProblemHandler handler = new TestProblemHandler(pb, integ);
integ.addStepHandler(handler);
integ.integrate(pb,
pb.getInitialTime(), pb.getInitialState(),
pb.getFinalTime(), new double[pb.getDimension()]);
}
@Test
public void testIncreasingTolerance()
throws DerivativeException, IntegratorException {
int previousCalls = Integer.MAX_VALUE;
for (int i = -12; i < -2; ++i) {
TestProblem1 pb = new TestProblem1();
double minStep = 0;
double maxStep = pb.getFinalTime() - pb.getInitialTime();
double scalAbsoluteTolerance = Math.pow(10.0, i);
double scalRelativeTolerance = 0.01 * scalAbsoluteTolerance;
FirstOrderIntegrator integ = new AdamsMoultonIntegrator(4, minStep, maxStep,
scalAbsoluteTolerance,
scalRelativeTolerance);
TestProblemHandler handler = new TestProblemHandler(pb, integ);
integ.addStepHandler(handler);
integ.integrate(pb,
pb.getInitialTime(), pb.getInitialState(),
pb.getFinalTime(), new double[pb.getDimension()]);
// the 0.15 and 3.0 factors are only valid for this test
// and has been obtained from trial and error
// there is no general relation between local and global errors
assertTrue(handler.getMaximalValueError() > (0.15 * scalAbsoluteTolerance));
assertTrue(handler.getMaximalValueError() < (3.0 * scalAbsoluteTolerance));
assertEquals(0, handler.getMaximalTimeError(), 1.0e-16);
int calls = pb.getCalls();
assertEquals(integ.getEvaluations(), calls);
assertTrue(calls <= previousCalls);
previousCalls = calls;
}
}
@Test(expected = DerivativeException.class)
public void exceedMaxEvaluations() throws DerivativeException, IntegratorException {
TestProblem1 pb = new TestProblem1();
double range = pb.getFinalTime() - pb.getInitialTime();
AdamsMoultonIntegrator integ = new AdamsMoultonIntegrator(2, 0, range, 1.0e-12, 1.0e-12);
TestProblemHandler handler = new TestProblemHandler(pb, integ);
integ.addStepHandler(handler);
integ.setMaxEvaluations(650);
integ.integrate(pb,
pb.getInitialTime(), pb.getInitialState(),
pb.getFinalTime(), new double[pb.getDimension()]);
}
@Test
public void backward() throws DerivativeException, IntegratorException {
TestProblem5 pb = new TestProblem5();
double range = Math.abs(pb.getFinalTime() - pb.getInitialTime());
FirstOrderIntegrator integ = new AdamsMoultonIntegrator(4, 0, range, 1.0e-12, 1.0e-12);
TestProblemHandler handler = new TestProblemHandler(pb, integ);
integ.addStepHandler(handler);
integ.integrate(pb, pb.getInitialTime(), pb.getInitialState(),
pb.getFinalTime(), new double[pb.getDimension()]);
assertTrue(handler.getLastError() < 1.0e-9);
assertTrue(handler.getMaximalValueError() < 1.0e-9);
assertEquals(0, handler.getMaximalTimeError(), 1.0e-16);
assertEquals("Adams-Moulton", integ.getName());
}
@Test
public void polynomial() throws DerivativeException, IntegratorException {
TestProblem6 pb = new TestProblem6();
double range = Math.abs(pb.getFinalTime() - pb.getInitialTime());
for (int nSteps = 1; nSteps < 7; ++nSteps) {
AdamsMoultonIntegrator integ =
new AdamsMoultonIntegrator(nSteps, 1.0e-6 * range, 0.1 * range, 1.0e-9, 1.0e-9);
TestProblemHandler handler = new TestProblemHandler(pb, integ);
integ.addStepHandler(handler);
integ.integrate(pb, pb.getInitialTime(), pb.getInitialState(),
pb.getFinalTime(), new double[pb.getDimension()]);
if (nSteps < 4) {
assertTrue(integ.getEvaluations() > 140);
} else {
assertTrue(integ.getEvaluations() < 90);
}
}
}
}