Package org.apache.commons.math3.ode.sampling

Class AbstractFieldStepInterpolator<T extends RealFieldElement<T>>

java.lang.Object

org.apache.commons.math3.ode.sampling.AbstractFieldStepInterpolator<T>

Type Parameters:

T - the type of the field elements

All Implemented Interfaces:

FieldStepInterpolator<T>

public abstract class AbstractFieldStepInterpolator<T extends RealFieldElement<T>>
extends Object
implements FieldStepInterpolator<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).

Since:

3.6

See Also:

• FirstOrderFieldIntegrator
• StepHandler

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractFieldStepInterpolator(boolean isForward, FieldODEStateAndDerivative<T> globalPreviousState, FieldODEStateAndDerivative<T> globalCurrentState, FieldODEStateAndDerivative<T> softPreviousState, FieldODEStateAndDerivative<T> softCurrentState, FieldEquationsMapper<T> equationsMapper)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
protected abstract FieldODEStateAndDerivative<T>	computeInterpolatedStateAndDerivatives(FieldEquationsMapper<T> equationsMapper, T time, T theta, T thetaH, T oneMinusThetaH)	Compute the state and derivatives at the interpolated time.
protected abstract AbstractFieldStepInterpolator<T>	create(boolean newForward, FieldODEStateAndDerivative<T> newGlobalPreviousState, FieldODEStateAndDerivative<T> newGlobalCurrentState, FieldODEStateAndDerivative<T> newSoftPreviousState, FieldODEStateAndDerivative<T> newSoftCurrentState, FieldEquationsMapper<T> newMapper)	Create a new instance.
FieldODEStateAndDerivative<T>	getCurrentState()	Get the state at current grid point time.
FieldODEStateAndDerivative<T>	getGlobalCurrentState()	Get the current global grid point state.
FieldODEStateAndDerivative<T>	getGlobalPreviousState()	Get the previous global grid point state.
FieldODEStateAndDerivative<T>	getInterpolatedState(T time)	Get the state at interpolated time.
FieldODEStateAndDerivative<T>	getPreviousState()	Get the state at previous grid point time.
boolean	isForward()	Check if the natural integration direction is forward.
AbstractFieldStepInterpolator<T>	restrictStep(FieldODEStateAndDerivative<T> previousState, FieldODEStateAndDerivative<T> 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 Details

AbstractFieldStepInterpolator

protected AbstractFieldStepInterpolator(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 Details

restrictStep

public AbstractFieldStepInterpolator<T> restrictStep(FieldODEStateAndDerivative<T> previousState,
 FieldODEStateAndDerivative<T> 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:

• getPreviousState()
• getCurrentState()

create

protected abstract AbstractFieldStepInterpolator<T> create(boolean newForward,
 FieldODEStateAndDerivative<T> newGlobalPreviousState,
 FieldODEStateAndDerivative<T> newGlobalCurrentState,
 FieldODEStateAndDerivative<T> newSoftPreviousState,
 FieldODEStateAndDerivative<T> newSoftCurrentState,
 FieldEquationsMapper<T> 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 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

getPreviousState

public FieldODEStateAndDerivative<T> getPreviousState()

Get the state at previous grid point time.

Specified by:

getPreviousState in interface FieldStepInterpolator<T extends RealFieldElement<T>>

Returns:

state at previous grid point time

getCurrentState

public FieldODEStateAndDerivative<T> getCurrentState()

Get the state at current grid point time.

Specified by:

getCurrentState in interface FieldStepInterpolator<T extends RealFieldElement<T>>

Returns:

state at current grid point time

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 FieldStepInterpolator<T extends RealFieldElement<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 FieldStepInterpolator<T extends RealFieldElement<T>>

Returns:

true if the integration variable (time) increases during integration

computeInterpolatedStateAndDerivatives

protected abstract FieldODEStateAndDerivative<T> computeInterpolatedStateAndDerivatives(FieldEquationsMapper<T> equationsMapper,
 T time,
 T theta,
 T thetaH,
 T oneMinusThetaH)
                                                                                 throws MaxCountExceededException

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:

MaxCountExceededException - if the number of functions evaluations is exceeded