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Commons Math example source code file (AdamsMoultonIntegratorTest.java)

This example Commons Math source code file (AdamsMoultonIntegratorTest.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Math tags/keywords

adams-moulton, adamsmoultonintegrator, adamsmoultonintegrator, derivativeexception, derivativeexception, firstorderintegrator, integratorexception, test, testproblem1, testproblem1, testproblem5, testproblem6, testproblemhandler, testproblemhandler

The Commons Math AdamsMoultonIntegratorTest.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

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);
            }
        }

    }

}

Other Commons Math examples (source code examples)

Here is a short list of links related to this Commons Math AdamsMoultonIntegratorTest.java source code file:

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