Interface StepHandler

All Known Implementing Classes:
ContinuousOutputModel, DummyStepHandler, StepNormalizer

public interface StepHandler

This interface represents a handler that should be called after each successful step.

The ODE integrators compute the evolution of the state vector at some grid points that depend on their own internal algorithm. Once they have found a new grid point (possibly after having computed several evaluation of the derivative at intermediate points), they provide it to objects implementing this interface. These objects typically either ignore the intermediate steps and wait for the last one, store the points in an ephemeris, or forward them to specialized processing or output methods.

See Also:
FirstOrderIntegrator, SecondOrderIntegrator, StepInterpolator

Method Summary
 void handleStep(StepInterpolator interpolator, boolean isLast)
          Handle the last accepted step
 boolean requiresDenseOutput()
          Determines whether this handler needs dense output.
 void reset()
          Reset the step handler.

Method Detail


boolean requiresDenseOutput()
Determines whether this handler needs dense output.

This method allows the integrator to avoid performing extra computation if the handler does not need dense output. If this method returns false, the integrator will call the handleStep(org.jscience.mathematics.analysis.ode.StepInterpolator, boolean) method with a DummyStepInterpolator rather than a custom interpolator.

true if the handler needs dense output


void reset()
Reset the step handler. Initialize the internal data as required before the first step is handled.


void handleStep(StepInterpolator interpolator,
                boolean isLast)
                throws DerivativeException
Handle the last accepted step

interpolator - interpolator for the last accepted step. For efficiency purposes, the various integrators reuse the same object on each call, so if the instance wants to keep it across all calls (for example to provide at the end of the integration a continuous model valid throughout the integration range, as the ContinuousOutputModel class does), it should build a local copy using the clone method of the interpolator and store this copy. Keeping only a reference to the interpolator and reusing it will result in unpredictable behaviour (potentially crashing the application).
isLast - true if the step is the last one
DerivativeException - this exception is propagated to the caller if the underlying user function triggers one