Class Integrator

java.lang.Object
  Integrator

All Implemented Interfaces:

java.lang.Runnable

Direct Known Subclasses:

RK4

public abstract class Integrator

extends java.lang.Object

implements java.lang.Runnable

Integrator is an abstract class which can be subclassed to create any kind of numerical integrator. All calculations are performed using Points enabling any dimension of problem to be solved without rewriting either this superclass or any its subclasses.

Field Summary

protected int	steps The number of steps being used for the integration.
protected double	x Current value of the independent variable that the integration is begin performed with respect to.
protected double	x0 Initial value of the independent variable that the integration is begin performed with respect to.
protected double	x1 Final value of the independent variable that the integration is begin performed with respect to.
protected Point	y Current state of the system being integrated.
protected Point	y0 Initial state of the system being integrated.

Constructor Summary

Integrator(double xStart, double xEnd, Point yStart, int steps)
Constructor to instantiate Integrator - never called directly.

Method Summary

abstract Point	function(double x, Point y) Method to calculate the required function which defines the problem being integrated.
double	getIV() Method used to return the current value of the independent variable.
Point	getLocation() Method used to return the current state of the system.
abstract Point	integrate() Abstract method which performs the numerical integration, implemented by any subclass of Integrator.
void	run() Method used to start a new thread performing the integration.
void	setEnd(double x1) Method used to reset the final value of the independent variable used in the numerical integration.
void	setSteps(int steps) Method used to reset the number of steps used in the numerical integration.
abstract java.lang.String	toString() Abstract method to return the problem being integrated in human readable form.

Methods inherited from class java.lang.Object

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

Field Detail

x0

protected final double x0

Initial value of the independent variable that the integration is begin performed with respect to.

x1

protected double x1

Final value of the independent variable that the integration is begin performed with respect to.

x

protected double x

Current value of the independent variable that the integration is begin performed with respect to.

y0

protected final Point y0

Initial state of the system being integrated.

y

protected Point y

Current state of the system being integrated.

steps

protected int steps

The number of steps being used for the integration.

Constructor Detail

Integrator

public Integrator(double xStart,
                  double xEnd,
                  Point yStart,
                  int steps)

Constructor to instantiate Integrator - never called directly.

Method Detail

integrate

public abstract Point integrate()

Abstract method which performs the numerical integration, implemented by any subclass of Integrator.

function

public abstract Point function(double x,
                               Point y)

Method to calculate the required function which defines the problem being integrated. This is calculated with respect to the independent variable x and perhaps wrt the Point y but this depends on the problem, e.g. an equation of motion integration would require the derivative of the Point y wrt x. This is abstract and must be implemented by the instance subclass of Integrator.

toString

public abstract java.lang.String toString()

Abstract method to return the problem being integrated in human readable form.

getLocation

public Point getLocation()

Method used to return the current state of the system. Used by the Display class in package compsim3.display.

getIV

public double getIV()

Method used to return the current value of the independent variable. Used by the Display class in package compsim3.display.

setSteps

public void setSteps(int steps)

Method used to reset the number of steps used in the numerical integration.

setEnd

public void setEnd(double x1)

Method used to reset the final value of the independent variable used in the numerical integration.

run

public void run()

Method used to start a new thread performing the integration. used by the display class in package compsim3.display.

Specified by:

run in interface java.lang.Runnable