Class ClassicalRungeKuttaFieldIntegrator<T extends RealFieldElement<T>>

java.lang.Object

org.apache.commons.math3.ode.AbstractFieldIntegrator<T>

org.apache.commons.math3.ode.nonstiff.RungeKuttaFieldIntegrator<T>

org.apache.commons.math3.ode.nonstiff.ClassicalRungeKuttaFieldIntegrator<T>

Type Parameters:

T - the type of the field elements

All Implemented Interfaces:

FirstOrderFieldIntegrator<T>, FieldButcherArrayProvider<T>

public class ClassicalRungeKuttaFieldIntegrator<T extends RealFieldElement<T>>
extends RungeKuttaFieldIntegrator<T>

This class implements the classical fourth order Runge-Kutta integrator for Ordinary Differential Equations (it is the most often used Runge-Kutta method).

This method is an explicit Runge-Kutta method, its Butcher-array is the following one :

   0  |  0    0    0    0
  1/2 | 1/2   0    0    0
  1/2 |  0   1/2   0    0
   1  |  0    0    1    0
      |--------------------
      | 1/6  1/3  1/3  1/6

Since:

3.6

See Also:

• EulerFieldIntegrator
• GillFieldIntegrator
• MidpointFieldIntegrator
• ThreeEighthesFieldIntegrator
• LutherFieldIntegrator

Constructor Summary

Constructors

Constructor	Description
ClassicalRungeKuttaFieldIntegrator(Field<T> field, T step)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
protected ClassicalRungeKuttaFieldStepInterpolator<T>	createInterpolator(boolean forward, T[][] yDotK, FieldODEStateAndDerivative<T> globalPreviousState, FieldODEStateAndDerivative<T> globalCurrentState, FieldEquationsMapper<T> mapper)	Create an interpolator.
T[][]	getA()	Get the internal weights from Butcher array (without the first empty row).
T[]	getB()	Get the external weights for the high order method from Butcher array.
T[]	getC()	Get the time steps from Butcher array (without the first zero).

Methods inherited from class RungeKuttaFieldIntegrator

fraction, integrate, singleStep

Methods inherited from class AbstractFieldIntegrator

acceptStep, addEventHandler, addEventHandler, addStepHandler, clearEventHandlers, clearStepHandlers, computeDerivatives, getCurrentSignedStepsize, getCurrentStepStart, getEquations, getEvaluations, getEvaluationsCounter, getEventHandlers, getField, getMaxEvaluations, getName, getStepHandlers, getStepSize, getStepStart, initIntegration, isLastStep, resetOccurred, sanityChecks, setIsLastStep, setMaxEvaluations, setStateInitialized, setStepSize, setStepStart

Methods inherited from class Object

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

Constructor Details

ClassicalRungeKuttaFieldIntegrator

public ClassicalRungeKuttaFieldIntegrator(Field<T> field,
 T step)

Simple constructor. Build a fourth-order Runge-Kutta integrator with the given step.

Parameters:

field - field to which the time and state vector elements belong

step - integration step

Method Details

getC

public T[] getC()

Get the time steps from Butcher array (without the first zero).

Returns:

time steps from Butcher array (without the first zero

getA

public T[][] getA()

Get the internal weights from Butcher array (without the first empty row).

Returns:

internal weights from Butcher array (without the first empty row)

getB

public T[] getB()

Get the external weights for the high order method from Butcher array.

Returns:

external weights for the high order method from Butcher array

createInterpolator

protected ClassicalRungeKuttaFieldStepInterpolator<T> createInterpolator(boolean forward,
 T[][] yDotK,
 FieldODEStateAndDerivative<T> globalPreviousState,
 FieldODEStateAndDerivative<T> globalCurrentState,
 FieldEquationsMapper<T> mapper)

Create an interpolator.

Specified by:

createInterpolator in class RungeKuttaFieldIntegrator<T extends RealFieldElement<T>>

Parameters:

forward - integration direction indicator

yDotK - slopes at the intermediate points

globalPreviousState - start of the global step

globalCurrentState - end of the global step

mapper - equations mapper for the all equations

Returns:

external weights for the high order method from Butcher array