double step = FastMath.abs(pb.getFinalTime() - pb.getInitialTime()) * 0.001;
FirstOrderIntegrator integ = new ClassicalRungeKuttaIntegrator(step);
TestProblemHandler handler = new TestProblemHandler(pb, integ);
integ.addStepHandler(handler);
integ.integrate(pb, pb.getInitialTime(), pb.getInitialState(),
pb.getFinalTime(), new double[pb.getDimension()]);
Assert.assertTrue(handler.getLastError() < 5.0e-10);
Assert.assertTrue(handler.getMaximalValueError() < 7.0e-10);
Assert.assertEquals(0, handler.getMaximalTimeError(), 1.0e-12);