edu.uci.ics.jung.algorithms.util
Class IterativeProcess

java.lang.Object
  edu.uci.ics.jung.algorithms.util.IterativeProcess

All Implemented Interfaces:

IterativeContext

Direct Known Subclasses:

AbstractRanker, EdmondsKarpMaxFlow

public abstract class IterativeProcess
extends Object
implements IterativeContext

Provides basic infrastructure for iterative algorithms. Services provided include:

• storage of current and max iteration count
• framework for initialization, iterative evaluation, and finalization
• test for convergence
• etc.

Algorithms that subclass this class are typically used in the following way:

 FooAlgorithm foo = new FooAlgorithm(...)
 foo.setMaximumIterations(100); //set up conditions
 ...
 foo.evaluate(); //key method which initiates iterative process
 foo.getSomeResult();
 

Author:

Scott White (originally written by Didier Besset)

Constructor Summary

IterativeProcess()
Generic constructor.

Method Summary

boolean	done() Returns true if this iterative process is finished, and false otherwise.
void	evaluate() Performs the iterative process.
protected void	finalizeIterations() Perform eventual clean-up operations (must be implement by subclass when needed).
double	getDesiredPrecision() Returns the desired precision.
int	getIterations() Returns the number of iterations performed.
int	getMaximumIterations() Returns the maximum allowed number of iterations.
double	getPrecision() Returns the attained precision.
boolean	hasConverged() Check to see if the result has been attained.
protected void	initializeIterations() Initializes internal parameters to start the iterative process.
double	relativePrecision(double epsilon, double x)
void	reset()
void	setDesiredPrecision(double prec) Defines the desired precision.
void	setMaximumIterations(int maxIter) Defines the maximum allowed number of iterations.
void	setPrecision(double precision)
abstract void	step() Evaluate the result of the current iteration.

Methods inherited from class java.lang.Object

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

Constructor Detail

IterativeProcess

public IterativeProcess()

Generic constructor.

Method Detail

evaluate

public void evaluate()

Performs the iterative process. Note: this method does not return anything because Java does not allow mixing double, int, or objects

step

public abstract void step()

Evaluate the result of the current iteration.

Specified by:

step in interface IterativeContext

finalizeIterations

protected void finalizeIterations()

Perform eventual clean-up operations (must be implement by subclass when needed).

getDesiredPrecision

public double getDesiredPrecision()

Returns the desired precision.

getIterations

public int getIterations()

Returns the number of iterations performed.

getMaximumIterations

public int getMaximumIterations()

Returns the maximum allowed number of iterations.

getPrecision

public double getPrecision()

Returns the attained precision.

setPrecision

public void setPrecision(double precision)

Parameters:

precision - the precision to set

hasConverged

public boolean hasConverged()

Check to see if the result has been attained.

Returns:

boolean

done

public boolean done()

Description copied from interface: IterativeContext

Returns true if this iterative process is finished, and false otherwise.

Specified by:

done in interface IterativeContext

initializeIterations

protected void initializeIterations()

Initializes internal parameters to start the iterative process.

reset

public void reset()

relativePrecision

public double relativePrecision(double epsilon,
                                double x)

Parameters:

epsilon - double

x - double

Returns:

double

setDesiredPrecision

public void setDesiredPrecision(double prec)
                         throws IllegalArgumentException

Defines the desired precision.

Throws:

IllegalArgumentException

setMaximumIterations

public void setMaximumIterations(int maxIter)
                          throws IllegalArgumentException

Defines the maximum allowed number of iterations.

Throws:

IllegalArgumentException