math.numerics
Class RK4

java.lang.Object
  math.numerics.RK4

All Implemented Interfaces:

ODESolver

public class RK4
extends java.lang.Object
implements ODESolver

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

Version:

1.0

Author:

Wolfgang Christian

Constructor Summary

RK4(ODE _ode)
Constructs the RK4 ODESolver for a system of ordinary differential equations.

Method Summary

double	getStepSize() Gets the step size.
void	initialize(double _stepSize) Initializes the ODE solver.
void	setStepSize(double _stepSize) Sets the step size.
double	step() Steps (advances) the differential equations by the stepSize.

Methods inherited from class java.lang.Object

equals, 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. Three rate arrays and four temporary state arrays are allocated. The number of differential equations is determined by invoking getState2().length on the ODE.

Specified by:

initialize in interface ODESolver

Parameters:

_stepSize -

step

public double step()

Steps (advances) the differential equations by the stepSize. The ODESolver invokes the ODE's getRate method to obtain the initial state of the system. The ODESolver then advances the solution and copies the new state into the state array affineTransform the end of the solution step.

Specified by:

step in interface ODESolver

Returns:

the step size

setStepSize

public void setStepSize(double _stepSize)

Sets the step size. The step size remains fixed in this algorithm.

Specified by:

setStepSize in interface ODESolver

Parameters:

_stepSize -

getStepSize

public double getStepSize()

Gets the step size. The stepsize is constant in this algorithm.

Specified by:

getStepSize in interface ODESolver

Returns:

the step size