java.lang.Object
- org.hipparchus.ode.sampling.AbstractFieldODEStateInterpolator<T>
- - org.hipparchus.ode.nonstiff.interpolators.RungeKuttaFieldStateInterpolator<T>
  - - org.hipparchus.ode.nonstiff.interpolators.ThreeEighthesFieldStateInterpolator<T>

Type Parameters:

T - the type of the field elements

All Implemented Interfaces:

FieldODEStateInterpolator<T>
```
public class ThreeEighthesFieldStateInterpolator<T extends CalculusFieldElement<T>>
extends RungeKuttaFieldStateInterpolator<T>
```
This class implements a step interpolator for the 3/8 fourth order Runge-Kutta integrator.
This interpolator allows to compute dense output inside the last step computed. The interpolation equation is consistent with the integration scheme :
- Using reference point at step start:
  y(t_n + θ h) = y (t_n) + θ (h/8) [ (8 - 15 θ + 8 θ²) y'₁ + 3 * (15 θ - 12 θ²) y'₂ + 3 θ y'₃ + (-3 θ + 4 θ²) y'₄ ]
- Using reference point at step end:
  y(t_n + θ h) = y (t_n + h) - (1 - θ) (h/8) [(1 - 7 θ + 8 θ²) y'₁ + 3 (1 + θ - 4 θ²) y'₂ + 3 (1 + θ) y'₃ + (1 + θ + 4 θ²) y'₄ ]
where θ belongs to [0 ; 1] and where y'₁ to y'₄ are the four evaluations of the derivatives already computed during the step.
See Also:

ThreeEighthesFieldIntegrator

Constructor Summary

Constructors
Constructor	Description
`ThreeEighthesFieldStateInterpolator(Field<T> field, boolean forward, T[][] yDotK, FieldODEStateAndDerivative<T> globalPreviousState, FieldODEStateAndDerivative<T> globalCurrentState, FieldODEStateAndDerivative<T> softPreviousState, FieldODEStateAndDerivative<T> softCurrentState, FieldEquationsMapper<T> mapper)`	Simple constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected FieldODEStateAndDerivative<T>`	`computeInterpolatedStateAndDerivatives(FieldEquationsMapper<T> mapper, T time, T theta, T thetaH, T oneMinusThetaH)`	Compute the state and derivatives at the interpolated time.
`protected ThreeEighthesFieldStateInterpolator<T>`	`create(Field<T> newField, boolean newForward, T[][] newYDotK, FieldODEStateAndDerivative<T> newGlobalPreviousState, FieldODEStateAndDerivative<T> newGlobalCurrentState, FieldODEStateAndDerivative<T> newSoftPreviousState, FieldODEStateAndDerivative<T> newSoftCurrentState, FieldEquationsMapper<T> newMapper)`	Create a new instance.

Methods inherited from class org.hipparchus.ode.nonstiff.interpolators.RungeKuttaFieldStateInterpolator
create, currentStateLinearCombination, derivativeLinearCombination, previousStateLinearCombination

Methods inherited from class org.hipparchus.ode.sampling.AbstractFieldODEStateInterpolator
getCurrentState, getGlobalCurrentState, getGlobalPreviousState, getInterpolatedState, getMapper, getPreviousState, isCurrentStateInterpolated, isForward, isPreviousStateInterpolated, restrictStep

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ThreeEighthesFieldStateInterpolator

public ThreeEighthesFieldStateInterpolator(Field<T> field,
                                           boolean forward,
                                           T[][] yDotK,
                                           FieldODEStateAndDerivative<T> globalPreviousState,
                                           FieldODEStateAndDerivative<T> globalCurrentState,
                                           FieldODEStateAndDerivative<T> softPreviousState,
                                           FieldODEStateAndDerivative<T> softCurrentState,
                                           FieldEquationsMapper<T> mapper)

Simple constructor.

Parameters:: field - field to which the time and state vector elements belong; forward - integration direction indicator; yDotK - slopes at the intermediate points; globalPreviousState - start of the global step; globalCurrentState - end of the global step; softPreviousState - start of the restricted step; softCurrentState - end of the restricted step; mapper - equations mapper for the all equations

Method Detail

create

protected ThreeEighthesFieldStateInterpolator<T> create(Field<T> newField,
                                                        boolean newForward,
                                                        T[][] newYDotK,
                                                        FieldODEStateAndDerivative<T> newGlobalPreviousState,
                                                        FieldODEStateAndDerivative<T> newGlobalCurrentState,
                                                        FieldODEStateAndDerivative<T> newSoftPreviousState,
                                                        FieldODEStateAndDerivative<T> newSoftCurrentState,
                                                        FieldEquationsMapper<T> newMapper)

Create a new instance.

Specified by:: create in class RungeKuttaFieldStateInterpolator<T extends CalculusFieldElement<T>>
Parameters:: newField - field to which the time and state vector elements belong; newForward - integration direction indicator; newYDotK - slopes at the intermediate points; 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

computeInterpolatedStateAndDerivatives

protected FieldODEStateAndDerivative<T> computeInterpolatedStateAndDerivatives(FieldEquationsMapper<T> mapper,
                                                                               T time,
                                                                               T theta,
                                                                               T thetaH,
                                                                               T oneMinusThetaH)

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.

Specified by:: computeInterpolatedStateAndDerivatives in class AbstractFieldODEStateInterpolator<T extends CalculusFieldElement<T>>
Parameters:: mapper - 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

Class ThreeEighthesFieldStateInterpolator<T extends CalculusFieldElement<T>>