org.opensourcephysics.numerics

Class RK45MultiStep

java.lang.Object

org.opensourcephysics.numerics.DormandPrince45

org.opensourcephysics.numerics.RK45

org.opensourcephysics.numerics.RK45MultiStep

All Implemented Interfaces:

ODEAdaptiveSolver, ODESolver

public class RK45MultiStep
extends RK45

Title: RK45MultiStep Description: Perform multiple RK4/5 ODE steps so that a uniform step size is maintained

Version:

1.0

Author:

Wolfgang Christian

Field Summary

Fields

Modifier and Type	Field and Description
protected int	maxIterations

Fields inherited from class org.opensourcephysics.numerics.DormandPrince45

enableExceptions, tol

Fields inherited from interface org.opensourcephysics.numerics.ODEAdaptiveSolver

BISECTION_EVENT_NOT_FOUND, DID_NOT_CONVERGE, NO_ERROR

Constructor Summary

Constructors

Constructor and Description
RK45MultiStep(ODE _ode) Constructs the RK45MultiStep ODESolver for a system of ordinary differential equations.

Method Summary

Methods

Modifier and Type	Method and Description
int	getErrorCode() Gets the error code.
double	getStepSize() Gets the step size.
void	initialize(double stepSize) Initializes the ODE solver.
void	setMaximumNumberOfErrorMessages(int n) Sets the number of error messages if ODE solver did not converge.
void	setMaxIterations(int n) Sets the maximum number of iterations.
void	setStepSize(double stepSize) Method setStepSize
double	step() Steps (advances) the differential equations by the stepSize.

Methods inherited from class org.opensourcephysics.numerics.DormandPrince45

enableRuntimeExpecptions, getTolerance, setTolerance

Methods inherited from class java.lang.Object

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

Field Detail

maxIterations

protected int maxIterations

Constructor Detail

RK45MultiStep

public RK45MultiStep(ODE _ode)

Constructs the RK45MultiStep ODESolver for a system of ordinary differential equations.

Parameters:

_ode - the system of differential equations.

Method Detail

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 at the end of the solution step.

Specified by:

step in interface ODESolver

Overrides:

step in class DormandPrince45

Returns:

the step size

setMaxIterations

public void setMaxIterations(int n)

Sets the maximum number of iterations.

Parameters:

n - maximum

setMaximumNumberOfErrorMessages

public void setMaximumNumberOfErrorMessages(int n)

Sets the number of error messages if ODE solver did not converge.

Parameters:

n - int

initialize

public void initialize(double stepSize)

Initializes the ODE solver. Temporary state and rate arrays are allocated by invoking the superclass method.

Specified by:

initialize in interface ODESolver

Overrides:

initialize in class DormandPrince45

Parameters:

stepSize -

setStepSize

public void setStepSize(double stepSize)

Method setStepSize

Specified by:

setStepSize in interface ODESolver

Overrides:

setStepSize in class DormandPrince45

Parameters:

stepSize -

getStepSize

public double getStepSize()

Gets the step size. The step size is the fixed step size, not the size of the RK4/5 steps that are combined into a single step.

Specified by:

getStepSize in interface ODESolver

Overrides:

getStepSize in class DormandPrince45

Returns:

the step size

getErrorCode

public int getErrorCode()

Gets the error code. Error codes: ODEAdaptiveSolver.NO_ERROR ODEAdaptiveSolver.DID_NOT_CONVERGE

Specified by:

getErrorCode in interface ODEAdaptiveSolver

Overrides:

getErrorCode in class DormandPrince45

Returns:

int