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());
}
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());
}