Examples of SwitchingFunction

org.apache.commons.math.ode.SwitchingFunction

This interface represents a switching function.

A switching function allows to handle discrete events in integration problems. These events occur for example when the integration process should be stopped as some value is reached (G-stop facility), or when the derivatives have discontinuities, or simply when the user wants to monitor some states boundaries crossings. These events are traditionally defined as occurring when a g function sign changes, hence the name switching functions.

Since events are only problem-dependent and are triggered by the independent time variable and the state vector, they can occur at virtually any time, unknown in advance. The integrators will take care to avoid sign changes inside the steps, they will reduce the step size when such an event is detected in order to put this event exactly at the end of the current step. This guarantees that step interpolation (which always has a one step scope) is relevant even in presence of discontinuities. This is independent from the stepsize control provided by integrators that monitor the local error (this feature is available on all integrators, including fixed step ones).

@version $Revision: 620312 $ $Date: 2008-02-10 12:28:59 -0700 (Sun, 10 Feb 2008) $ @since 1.2

          new HighamHall54Integrator(minStep, maxStep,
                                     scalAbsoluteTolerance, scalRelativeTolerance);
      TestProblemHandler handler = new TestProblemHandler(pb, integ);
      integ.setStepHandler(handler);


      integ.addSwitchingFunction(new SwitchingFunction() {
        public int eventOccurred(double t, double[] y) {
          return SwitchingFunction.CONTINUE;
        }
        public double g(double t, double[] y) throws FunctionEvaluationException {
          double middle = (pb.getInitialTime() + pb.getFinalTime()) / 2;

        new HighamHall54Integrator(minStep, maxStep,
                                   scalAbsoluteTolerance, scalRelativeTolerance);
    TestProblemHandler handler = new TestProblemHandler(pb, integ);
    integ.setStepHandler(handler);


    integ.addSwitchingFunction(new SwitchingFunction() {
      public int eventOccurred(double t, double[] y) {
        return SwitchingFunction.CONTINUE;
      }
      public double g(double t, double[] y) {
        double middle = (pb.getInitialTime() + pb.getFinalTime()) / 2;

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Examples of SwitchingFunction

Examples of org.apache.commons.math.ode.SwitchingFunction

Examples of org.apache.commons.math.ode.SwitchingFunction