public void testBackward() throws DerivativeException, IntegratorException {

    TestProblem5 pb = new TestProblem5();
    double minStep = 0;
    double maxStep = pb.getFinalTime() - pb.getInitialTime();
    double scalAbsoluteTolerance = 1.0e-8;
    double scalRelativeTolerance = 0.01 * scalAbsoluteTolerance;

    FirstOrderIntegrator integ =
        new GraggBulirschStoerIntegrator(
            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()]);

    assertTrue(handler.getLastError() < 9.0e-10);
    assertTrue(handler.getMaximalValueError() < 9.0e-10);
    assertEquals(0, handler.getMaximalTimeError(), 1.0e-12);
    assertEquals("Gragg-Bulirsch-Stoer", integ.getName());
  }
Пример #2
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  public void testKepler() throws DerivativeException, IntegratorException {

    final TestProblem3 pb = new TestProblem3(0.9);
    double minStep = 0;
    double maxStep = pb.getFinalTime() - pb.getInitialTime();
    double[] vecAbsoluteTolerance = {1.0e-8, 1.0e-8, 1.0e-10, 1.0e-10};
    double[] vecRelativeTolerance = {1.0e-10, 1.0e-10, 1.0e-8, 1.0e-8};

    FirstOrderIntegrator integ =
        new HighamHall54Integrator(minStep, maxStep, vecAbsoluteTolerance, vecRelativeTolerance);
    integ.addStepHandler(new KeplerHandler(pb));
    integ.integrate(
        pb,
        pb.getInitialTime(),
        pb.getInitialState(),
        pb.getFinalTime(),
        new double[pb.getDimension()]);
    assertEquals("Higham-Hall 5(4)", integ.getName());
  }
  public void testVariableSteps() throws DerivativeException, IntegratorException {

    final 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;
    FirstOrderIntegrator integ =
        new GraggBulirschStoerIntegrator(
            minStep, maxStep,
            absTolerance, relTolerance);
    integ.addStepHandler(new VariableStepHandler());
    double stopTime =
        integ.integrate(
            pb,
            pb.getInitialTime(),
            pb.getInitialState(),
            pb.getFinalTime(),
            new double[pb.getDimension()]);
    assertEquals(pb.getFinalTime(), stopTime, 1.0e-10);
    assertEquals("Gragg-Bulirsch-Stoer", integ.getName());
  }