@Test
public void testTooLargeFirstStep()
throws DimensionMismatchException, NumberIsTooSmallException, MaxCountExceededException,
NoBracketingException {
AdaptiveStepsizeIntegrator integ =
new DormandPrince853Integrator(0, Double.POSITIVE_INFINITY, Double.NaN, Double.NaN);
final double start = 0.0;
final double end = 0.001;
FirstOrderDifferentialEquations equations =
new FirstOrderDifferentialEquations() {
public int getDimension() {
return 1;
}
public void computeDerivatives(double t, double[] y, double[] yDot) {
Assert.assertTrue(t >= FastMath.nextAfter(start, Double.NEGATIVE_INFINITY));
Assert.assertTrue(t <= FastMath.nextAfter(end, Double.POSITIVE_INFINITY));
yDot[0] = -100.0 * y[0];
}
};
integ.setStepSizeControl(0, 1.0, 1.0e-6, 1.0e-8);
integ.integrate(equations, start, new double[] {1.0}, end, new double[1]);
}
public void testDimensionCheck() {
try {
TestProblem1 pb = new TestProblem1();
AdaptiveStepsizeIntegrator integrator =
new GraggBulirschStoerIntegrator(0.0, 1.0, 1.0e-10, 1.0e-10);
integrator.integrate(
pb, 0.0, new double[pb.getDimension() + 10], 1.0, new double[pb.getDimension() + 10]);
fail("an exception should have been thrown");
} catch (DerivativeException de) {
fail("wrong exception caught");
} catch (IntegratorException ie) {
}
}
@Test
public void testIncreasingTolerance()
throws DimensionMismatchException, NumberIsTooSmallException, MaxCountExceededException,
NoBracketingException {
int previousCalls = Integer.MAX_VALUE;
AdaptiveStepsizeIntegrator integ =
new DormandPrince853Integrator(0, Double.POSITIVE_INFINITY, Double.NaN, Double.NaN);
for (int i = -12; i < -2; ++i) {
TestProblem1 pb = new TestProblem1();
double minStep = 0;
double maxStep = pb.getFinalTime() - pb.getInitialTime();
double scalAbsoluteTolerance = FastMath.pow(10.0, i);
double scalRelativeTolerance = 0.01 * scalAbsoluteTolerance;
integ.setStepSizeControl(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 1.3 factor is only valid for this test
// and has been obtained from trial and error
// there is no general relation between local and global errors
Assert.assertTrue(handler.getMaximalValueError() < (1.3 * scalAbsoluteTolerance));
Assert.assertEquals(0, handler.getMaximalTimeError(), 1.0e-12);
int calls = pb.getCalls();
Assert.assertEquals(integ.getEvaluations(), calls);
Assert.assertTrue(calls <= previousCalls);
previousCalls = calls;
}
}
