Package org.opensourcephysics.numerics

Class RK4

java.lang.Object

org.opensourcephysics.numerics.AbstractODESolver

org.opensourcephysics.numerics.RK4

All Implemented Interfaces:

ODESolver

Direct Known Subclasses:

Adams4

public class RK4
extends AbstractODESolver

Title: RK4 Description: A fourth order Runge-Kutta ODE solver.

Field Summary

Fields inherited from class org.opensourcephysics.numerics.AbstractODESolver

numEqn, ode, stepSize

Constructor Summary

Constructors

Constructor	Description
RK4(ODE ode)	Constructs the RK4 ODESolver for a system of ordinary differential equations.

Method Summary

Modifier and Type	Method	Description
void	initialize(double stepSize)	Initializes the ODE solver and allocates the rate and state arrays.
double	step()	Steps (advances) the differential equations by the stepSize.

Methods inherited from class org.opensourcephysics.numerics.AbstractODESolver

getStepSize, setStepSize

Methods inherited from class java.lang.Object

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

Constructor Detail

RK4

public RK4(ODE ode)

Constructs the RK4 ODESolver for a system of ordinary differential equations.

Parameters:

ode - the system of differential equations.

Method Detail

initialize

public void initialize(double stepSize)

Initializes the ODE solver and allocates the rate and state arrays. The number of differential equations is determined by invoking getState().length on the superclass.

Specified by:

initialize in interface ODESolver

Overrides:

initialize in class AbstractODESolver

Parameters:

stepSize -

step

public double step()

Steps (advances) the differential equations by the stepSize. The ODESolver invokes the ODE's getRate method to compute the rate at various intermediate states. The ODESolver then advances the solution and copies the new state into the ODE's state array at the end of the solution step.

Specified by:

step in interface ODESolver

Specified by:

step in class AbstractODESolver

Returns:

the step size