org.opensourcephysics.numerics
Class EulerRichardson

java.lang.Object
  extended by org.opensourcephysics.numerics.AbstractODESolver
      extended by org.opensourcephysics.numerics.EulerRichardson
All Implemented Interfaces:
ODESolver

public class EulerRichardson
extends AbstractODESolver

An Euler-Richardson (midpoint) method ODE solver. The Euler-Richardson method uses the state at the beginning of the interval to estimate the state at the midpoint. x(midpoint) = x(n) + v(n)*dt/2 v(midpoint) = v(n) + a(n)*dt/2 t(midpoint) = t(n) + dt/2 The midpoint state is then used to calculate the final state.

Version:
1.0
Author:
Wolfgang Christian

Field Summary
 
Fields inherited from class org.opensourcephysics.numerics.AbstractODESolver
numEqn, ode, stepSize
 
Constructor Summary
EulerRichardson(ODE ode)
          Constructs the EulerRichardson ODESolver for a system of ordinary differential equations.
 
Method Summary
 void initialize(double stepSize)
          Initializes the ODE solver.
 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

EulerRichardson

public EulerRichardson(ODE ode)
Constructs the EulerRichardson 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. The rate and midstate arrays are allocated. The number of differential equations is determined by invoking getState().length on the ODE.

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 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