Package org.hipparchus.ode.sampling

Class AbstractODEStateInterpolator

java.lang.Object

org.hipparchus.ode.sampling.AbstractODEStateInterpolator

All Implemented Interfaces:

Serializable, ODEStateInterpolator

Direct Known Subclasses:

AdamsStateInterpolator, GraggBulirschStoerStateInterpolator, RungeKuttaStateInterpolator

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:

ODEIntegrator, ODEStepHandler, Serialized Form

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractODEStateInterpolator(boolean isForward, ODEStateAndDerivative globalPreviousState, ODEStateAndDerivative globalCurrentState, ODEStateAndDerivative softPreviousState, ODEStateAndDerivative softCurrentState, EquationsMapper equationsMapper)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
protected abstract ODEStateAndDerivative	computeInterpolatedStateAndDerivatives(EquationsMapper equationsMapper, double time, double theta, double thetaH, double oneMinusThetaH)	Compute the state and derivatives at the interpolated time.
protected abstract AbstractODEStateInterpolator	create(boolean newForward, ODEStateAndDerivative newGlobalPreviousState, ODEStateAndDerivative newGlobalCurrentState, ODEStateAndDerivative newSoftPreviousState, ODEStateAndDerivative newSoftCurrentState, EquationsMapper newMapper)	Create a new instance.
ODEStateAndDerivative	getCurrentState()	Get the state at current grid point time.
ODEStateAndDerivative	getGlobalCurrentState()	Get the current global grid point state.
ODEStateAndDerivative	getGlobalPreviousState()	Get the previous global grid point state.
ODEStateAndDerivative	getInterpolatedState(double time)	Get the state at interpolated time.
protected EquationsMapper	getMapper()	Get the mapper for ODE equations primary and secondary components.
ODEStateAndDerivative	getPreviousState()	Get the state at previous grid point time.
boolean	isCurrentStateInterpolated()	Determines if the current state is computed directly by the integrator, or if it is calculated using interpolation.
boolean	isForward()	Check if the natural integration direction is forward.
boolean	isPreviousStateInterpolated()	Determines if the previous state is computed directly by the integrator, or if it is calculated using interpolation.
AbstractODEStateInterpolator	restrictStep(ODEStateAndDerivative previousState, ODEStateAndDerivative currentState)	Create a new restricted version of the instance.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

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 Detail

restrictStep

public AbstractODEStateInterpolator restrictStep(ODEStateAndDerivative previousState,
                                                 ODEStateAndDerivative currentState)

Create a new restricted version of the instance.

The instance is not changed at all.

Specified by:

restrictStep in interface ODEStateInterpolator

Parameters:

previousState - start of the restricted step

currentState - end of the restricted step

Returns:

restricted version of the instance

See Also:

ODEStateInterpolator.getPreviousState(), ODEStateInterpolator.getCurrentState()

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