Package org.hipparchus.ode.sampling

Class AbstractODEStateInterpolator

java.lang.Object
org.hipparchus.ode.sampling.AbstractODEStateInterpolator
All Implemented Interfaces:
Serializable, ODEStateInterpolator
public abstract class AbstractODEStateInterpolator extends Object implements ODEStateInterpolator
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:

  • Constructor Details

    • AbstractODEStateInterpolator

      protected AbstractODEStateInterpolator(boolean isForward, ODEStateAndDerivative globalPreviousState, ODEStateAndDerivative globalCurrentState, ODEStateAndDerivative softPreviousState, ODEStateAndDerivative softCurrentState, EquationsMapper 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 Details

    • restrictStep

      public AbstractODEStateInterpolator restrictStep(ODEStateAndDerivative previousState, ODEStateAndDerivative currentState)
      Create a new restricted version of the instance.

      The instance is not changed at all.

      Parameters:
      previousState - start of the restricted step
      currentState - end of the restricted step
      Returns:
      restricted version of the instance
      See Also:

    • create

      protected abstract AbstractODEStateInterpolator create(boolean newForward, ODEStateAndDerivative newGlobalPreviousState, ODEStateAndDerivative newGlobalCurrentState, ODEStateAndDerivative newSoftPreviousState, ODEStateAndDerivative newSoftCurrentState, EquationsMapper newMapper)
      Create a new instance.
      Parameters:
      newForward - integration direction indicator
      newGlobalPreviousState - start of the global step
      newGlobalCurrentState - end of the global step
      newSoftPreviousState - start of the restricted step
      newSoftCurrentState - end of the restricted step
      newMapper - equations mapper for the all equations
      Returns:
      a new instance

    • getGlobalPreviousState

      public ODEStateAndDerivative getGlobalPreviousState()
      Get the previous global grid point state.
      Returns:
      previous global grid point state

    • getGlobalCurrentState

      public ODEStateAndDerivative getGlobalCurrentState()
      Get the current global grid point state.
      Returns:
      current global grid point state

    • getPreviousState

      public ODEStateAndDerivative getPreviousState()
      Get the state at previous grid point time.
      Specified by:
      getPreviousState in interface ODEStateInterpolator
      Returns:
      state at previous grid point time

    • 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 ODEStateInterpolator
      Returns:
      true if the previous state was calculated by the interpolator and false if it was computed directly by the integrator.

    • getCurrentState

      public ODEStateAndDerivative getCurrentState()
      Get the state at current grid point time.
      Specified by:
      getCurrentState in interface ODEStateInterpolator
      Returns:
      state at current grid point time

    • 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 ODEStateInterpolator
      Returns:
      true if the current state was calculated by the interpolator and false if it was computed directly by the integrator.

    • getInterpolatedState

      public ODEStateAndDerivative getInterpolatedState(double 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 ODEStateInterpolator
      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 ODEStateInterpolator
      Returns:
      true if the integration variable (time) increases during integration

    • getMapper

      protected EquationsMapper getMapper()
      Get the mapper for ODE equations primary and secondary components.
      Returns:
      mapper for ODE equations primary and secondary components

    • computeInterpolatedStateAndDerivatives

      protected abstract ODEStateAndDerivative computeInterpolatedStateAndDerivatives(EquationsMapper equationsMapper, double time, double theta, double thetaH, double 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