org.apache.commons.math3.ode.nonstiff

Class LutherFieldIntegrator<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.LutherFieldIntegrator<T>

Type Parameters:

T - the type of the field elements

All Implemented Interfaces:

FirstOrderFieldIntegrator<T>, FieldButcherArrayProvider<T>

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

This class implements the Luther sixth order Runge-Kutta integrator for Ordinary Differential Equations.

This method is described in H. A. Luther 1968 paper An explicit Sixth-Order Runge-Kutta Formula.

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

        0   |               0                     0                     0                     0                     0                     0
        1   |               1                     0                     0                     0                     0                     0
       1/2  |              3/8                   1/8                    0                     0                     0                     0
       2/3  |              8/27                  2/27                  8/27                   0                     0                     0
   (7-q)/14 | (  -21 +   9q)/392    (  -56 +   8q)/392    (  336 -  48q)/392    (  -63 +   3q)/392                  0                     0
   (7+q)/14 | (-1155 - 255q)/1960   ( -280 -  40q)/1960   (    0 - 320q)/1960   (   63 + 363q)/1960   ( 2352 + 392q)/1960                 0
        1   | (  330 + 105q)/180    (  120 +   0q)/180    ( -200 + 280q)/180    (  126 - 189q)/180    ( -686 - 126q)/180     ( 490 -  70q)/180
            |--------------------------------------------------------------------------------------------------------------------------------------------------
            |              1/20                   0                   16/45                  0                   49/180                 49/180         1/20
 

where q = √21

Since:

3.6

See Also:

EulerFieldIntegrator, ClassicalRungeKuttaFieldIntegrator, GillFieldIntegrator, MidpointFieldIntegrator, ThreeEighthesFieldIntegrator

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
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 org.apache.commons.math3.ode.nonstiff.RungeKuttaFieldIntegrator

integrate, singleStep

Methods inherited from class org.apache.commons.math3.ode.AbstractFieldIntegrator

addEventHandler, addEventHandler, addStepHandler, clearEventHandlers, clearStepHandlers, computeDerivatives, getCurrentSignedStepsize, getCurrentStepStart, getEvaluations, getEventHandlers, getField, getMaxEvaluations, getName, getStepHandlers, setMaxEvaluations

Methods inherited from class java.lang.Object

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

Constructor Detail

LutherFieldIntegrator

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

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

Parameters:

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

step - integration step

Method Detail

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