Package org.opensourcephysics.numerics

Class Ralston2

java.lang.Object

org.opensourcephysics.numerics.AbstractODESolver

org.opensourcephysics.numerics.Ralston2

All Implemented Interfaces:

ODESolver

public class Ralston2
extends AbstractODESolver

Ralston2 implements Ralston's algorithm for solving ODEs by evaluating the rate at the initial state, estimating the rate for the final state, and using a weighted average of these two rates to advance the state.

Field Summary

Fields inherited from class org.opensourcephysics.numerics.AbstractODESolver

numEqn, ode, stepSize

Constructor Summary

Constructors

Constructor	Description
Ralston2(ODE ode)	Constructor Ralston2

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

Ralston2

public Ralston2(ODE ode)

Constructor Ralston2

Parameters:

ode -

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 getState method to obtain the initial state of the system. The ODESolver then uses this state estimate the rate a intermediate points. Finally, the ODESolver advances the solution and copies the new state into the 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