public void testEvents() throws DerivativeException, IntegratorException {
TestProblem4 pb = new TestProblem4();
double minStep = 0;
double maxStep = pb.getFinalTime() - pb.getInitialTime();
double scalAbsoluteTolerance = 1.0e-8;
double scalRelativeTolerance = 0.01 * scalAbsoluteTolerance;
FirstOrderIntegrator integ =
new HighamHall54Integrator(minStep, maxStep, scalAbsoluteTolerance, scalRelativeTolerance);
TestProblemHandler handler = new TestProblemHandler(pb, integ);
integ.addStepHandler(handler);
EventHandler[] functions = pb.getEventsHandlers();
for (int l = 0; l < functions.length; ++l) {
integ.addEventHandler(functions[l], Double.POSITIVE_INFINITY, 1.0e-8 * maxStep, 1000);
}
assertEquals(functions.length, integ.getEventHandlers().size());
integ.integrate(
pb,
pb.getInitialTime(),
pb.getInitialState(),
pb.getFinalTime(),
new double[pb.getDimension()]);
assertTrue(handler.getMaximalValueError() < 1.0e-7);
assertEquals(0, handler.getMaximalTimeError(), 1.0e-12);
assertEquals(12.0, handler.getLastTime(), 1.0e-8 * maxStep);
integ.clearEventHandlers();
assertEquals(0, integ.getEventHandlers().size());
}
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 HighamHall54Integrator(
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
assertTrue(handler.getMaximalValueError() < (1.3 * scalAbsoluteTolerance));
assertEquals(0, handler.getMaximalTimeError(), 1.0e-12);
int calls = pb.getCalls();
assertEquals(integ.getEvaluations(), calls);
assertTrue(calls <= previousCalls);
previousCalls = calls;
}
}
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());
}
private double getMaxError(FirstOrderIntegrator integrator, TestProblemAbstract pb)
throws DerivativeException, IntegratorException {
TestProblemHandler handler = new TestProblemHandler(pb, integrator);
integrator.addStepHandler(handler);
integrator.integrate(
pb,
pb.getInitialTime(),
pb.getInitialState(),
pb.getFinalTime(),
new double[pb.getDimension()]);
return handler.getMaximalValueError();
}
public void testIncreasingTolerance() throws DerivativeException, IntegratorException {
int previousCalls = Integer.MAX_VALUE;
for (int i = -12; i < -4; ++i) {
TestProblem1 pb = new TestProblem1();
double minStep = 0;
double maxStep = pb.getFinalTime() - pb.getInitialTime();
double absTolerance = Math.pow(10.0, i);
double relTolerance = absTolerance;
FirstOrderIntegrator integ =
new GraggBulirschStoerIntegrator(
minStep, maxStep,
absTolerance, relTolerance);
TestProblemHandler handler = new TestProblemHandler(pb, integ);
integ.addStepHandler(handler);
integ.integrate(
pb,
pb.getInitialTime(),
pb.getInitialState(),
pb.getFinalTime(),
new double[pb.getDimension()]);
// the coefficients are only valid for this test
// and have been obtained from trial and error
// there is no general relation between local and global errors
double ratio = handler.getMaximalValueError() / absTolerance;
assertTrue(ratio < 2.4);
assertTrue(ratio > 0.02);
assertEquals(0, handler.getMaximalTimeError(), 1.0e-12);
int calls = pb.getCalls();
assertEquals(integ.getEvaluations(), calls);
assertTrue(calls <= previousCalls);
previousCalls = calls;
}
}
