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 testMinStep() {
try {
TestProblem5 pb = new TestProblem5();
double minStep = 0.1 * Math.abs(pb.getFinalTime() - pb.getInitialTime());
double maxStep = Math.abs(pb.getFinalTime() - pb.getInitialTime());
double[] vecAbsoluteTolerance = {1.0e-20, 1.0e-21};
double[] vecRelativeTolerance = {1.0e-20, 1.0e-21};
FirstOrderIntegrator integ =
new GraggBulirschStoerIntegrator(
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()]);
fail("an exception should have been thrown");
} catch (DerivativeException de) {
fail("wrong exception caught");
} catch (IntegratorException ie) {
}
}