コード例 #1
0
  public void testModelsMerging() throws DerivativeException, IntegratorException {

    // theoretical solution: y[0] = cos(t), y[1] = sin(t)
    FirstOrderDifferentialEquations problem =
        new FirstOrderDifferentialEquations() {
          public void computeDerivatives(double t, double[] y, double[] dot)
              throws DerivativeException {
            dot[0] = -y[1];
            dot[1] = y[0];
          }

          public int getDimension() {
            return 2;
          }
        };

    // integrate backward from π to 0;
    ContinuousOutputModel cm1 = new ContinuousOutputModel();
    FirstOrderIntegrator integ1 = new DormandPrince853Integrator(0, 1.0, 1.0e-8, 1.0e-8);
    integ1.setStepHandler(cm1);
    integ1.integrate(problem, Math.PI, new double[] {-1.0, 0.0}, 0, new double[2]);

    // integrate backward from 2π to π
    ContinuousOutputModel cm2 = new ContinuousOutputModel();
    FirstOrderIntegrator integ2 = new DormandPrince853Integrator(0, 0.1, 1.0e-12, 1.0e-12);
    integ2.setStepHandler(cm2);
    integ2.integrate(problem, 2.0 * Math.PI, new double[] {1.0, 0.0}, Math.PI, new double[2]);

    // merge the two half circles
    ContinuousOutputModel cm = new ContinuousOutputModel();
    cm.append(cm2);
    cm.append(new ContinuousOutputModel());
    cm.append(cm1);

    // check circle
    assertEquals(2.0 * Math.PI, cm.getInitialTime(), 1.0e-12);
    assertEquals(0, cm.getFinalTime(), 1.0e-12);
    assertEquals(cm.getFinalTime(), cm.getInterpolatedTime(), 1.0e-12);
    for (double t = 0; t < 2.0 * Math.PI; t += 0.1) {
      cm.setInterpolatedTime(t);
      double[] y = cm.getInterpolatedState();
      assertEquals(Math.cos(t), y[0], 1.0e-7);
      assertEquals(Math.sin(t), y[1], 1.0e-7);
    }
  }
コード例 #2
0
 private boolean checkAppendError(ContinuousOutputModel cm, double t0, double[] y0, double t1)
     throws DerivativeException {
   try {
     ContinuousOutputModel otherCm = new ContinuousOutputModel();
     otherCm.handleStep(buildInterpolator(t0, y0, t1), true);
     cm.append(otherCm);
   } catch (IllegalArgumentException iae) {
     // expected behavior
     return true;
   }
   return false;
 }