Class AbstractFieldODEStateInterpolator<T extends CalculusFieldElement<T>>

  • Type Parameters:
    T - the type of the field elements
    All Implemented Interfaces:
    FieldODEStateInterpolator<T>

    public abstract class AbstractFieldODEStateInterpolator<T extends CalculusFieldElement<T>>
    extends Object
    implements FieldODEStateInterpolator<T>
    This abstract class represents an interpolator over the last step during an ODE integration.

    The various ODE integrators provide objects extending this class to the step handlers. The handlers can use these objects to retrieve the state vector at intermediate times between the previous and the current grid points (dense output).

    See Also:
    FieldODEIntegrator, FieldODEStepHandler
    • Constructor Detail

      • AbstractFieldODEStateInterpolator

        protected AbstractFieldODEStateInterpolator​(boolean isForward,
                                                    FieldODEStateAndDerivative<T> globalPreviousState,
                                                    FieldODEStateAndDerivative<T> globalCurrentState,
                                                    FieldODEStateAndDerivative<T> softPreviousState,
                                                    FieldODEStateAndDerivative<T> softCurrentState,
                                                    FieldEquationsMapper<T> equationsMapper)
        Simple constructor.
        Parameters:
        isForward - integration direction indicator
        globalPreviousState - start of the global step
        globalCurrentState - end of the global step
        softPreviousState - start of the restricted step
        softCurrentState - end of the restricted step
        equationsMapper - mapper for ODE equations primary and secondary components
    • Method Detail

      • getGlobalPreviousState

        public FieldODEStateAndDerivative<T> getGlobalPreviousState()
        Get the previous global grid point state.
        Returns:
        previous global grid point state
      • getGlobalCurrentState

        public FieldODEStateAndDerivative<T> getGlobalCurrentState()
        Get the current global grid point state.
        Returns:
        current global grid point state
      • isPreviousStateInterpolated

        public boolean isPreviousStateInterpolated()
        Determines if the previous state is computed directly by the integrator, or if it is calculated using interpolation.

        Typically the previous state is directly computed by the integrator, but when events are detected the steps are shortened so that events occur on step boundaries which means the previous state may be computed by the interpolator.

        Specified by:
        isPreviousStateInterpolated in interface FieldODEStateInterpolator<T extends CalculusFieldElement<T>>
        Returns:
        true if the previous state was calculated by the interpolator and false if it was computed directly by the integrator.
      • isCurrentStateInterpolated

        public boolean isCurrentStateInterpolated()
        Determines if the current state is computed directly by the integrator, or if it is calculated using interpolation.

        Typically the current state is directly computed by the integrator, but when events are detected the steps are shortened so that events occur on step boundaries which means the current state may be computed by the interpolator.

        Specified by:
        isCurrentStateInterpolated in interface FieldODEStateInterpolator<T extends CalculusFieldElement<T>>
        Returns:
        true if the current state was calculated by the interpolator and false if it was computed directly by the integrator.
      • getInterpolatedState

        public FieldODEStateAndDerivative<T> getInterpolatedState​(T time)
        Get the state at interpolated time.

        Setting the time outside of the current step is allowed, but should be used with care since the accuracy of the interpolator will probably be very poor far from this step. This allowance has been added to simplify implementation of search algorithms near the step endpoints.

        Specified by:
        getInterpolatedState in interface FieldODEStateInterpolator<T extends CalculusFieldElement<T>>
        Parameters:
        time - time of the interpolated point
        Returns:
        state at interpolated time
      • isForward

        public boolean isForward()
        Check if the natural integration direction is forward.

        This method provides the integration direction as specified by the integrator itself, it avoid some nasty problems in degenerated cases like null steps due to cancellation at step initialization, step control or discrete events triggering.

        Specified by:
        isForward in interface FieldODEStateInterpolator<T extends CalculusFieldElement<T>>
        Returns:
        true if the integration variable (time) increases during integration
      • getMapper

        protected FieldEquationsMapper<T> getMapper()
        Get the mapper for ODE equations primary and secondary components.
        Returns:
        mapper for ODE equations primary and secondary components
      • computeInterpolatedStateAndDerivatives

        protected abstract FieldODEStateAndDerivative<T> computeInterpolatedStateAndDerivatives​(FieldEquationsMapper<T> equationsMapper,
                                                                                                T time,
                                                                                                T theta,
                                                                                                T thetaH,
                                                                                                T oneMinusThetaH)
                                                                                         throws MathIllegalStateException
        Compute the state and derivatives at the interpolated time. This is the main processing method that should be implemented by the derived classes to perform the interpolation.
        Parameters:
        equationsMapper - mapper for ODE equations primary and secondary components
        time - interpolation time
        theta - normalized interpolation abscissa within the step (theta is zero at the previous time step and one at the current time step)
        thetaH - time gap between the previous time and the interpolated time
        oneMinusThetaH - time gap between the interpolated time and the current time
        Returns:
        interpolated state and derivatives
        Throws:
        MathIllegalStateException - if the number of functions evaluations is exceeded