Package unifeat.featureSelection.wrapper.PSOBasedMethods.CPSO

Class Swarm

java.lang.Object

unifeat.featureSelection.wrapper.PSOBasedMethods.BasicSwarm<Double,Particle>

unifeat.featureSelection.wrapper.PSOBasedMethods.CPSO.Swarm

public class Swarm
extends BasicSwarm<Double,Particle>

This java class is used to implement a swarm of particles in continuous particle swarm optimization (CPSO) method in which the type of position vector is double and the type of particle is extended from Particle class.

Author:

Sina Tabakhi

See Also:

• BasicSwarm

Field Summary

Fields

Modifier and Type	Field	Description
private Random	rand
private int	seedValue

Fields inherited from class unifeat.featureSelection.wrapper.PSOBasedMethods.BasicSwarm

C1, C2, END_POS_INTERVAL, fitnessEvaluator, gBest, INERTIA_WEIGHT, MAX_VELOCITY, MIN_VELOCITY, population, POPULATION_SIZE, PROBLEM_DIMENSION, START_POS_INTERVAL

Constructor Summary

Constructors

Constructor	Description
Swarm(double theta)	Initializes the parameters

Method Summary

Modifier and Type	Method	Description
void	evaluateFitness()	This method evaluates the fitness of each particle in the swarm by predefined fitness function.
void	initialization()	This method initializes the position and velocity vectors of each particle in the swarm.
void	updateGlobalBest()	This method updates the global best position (global best) of the swarm.
void	updateParticlePosition()	This method updates the position vector of each particle in the swarm.
void	updateParticleVelocity()	This method updates the velocity vector of each particle in the swarm.
void	updatePersonalBest()	This method updates the best position (personal best) of each particle in the swarm.

Methods inherited from class unifeat.featureSelection.wrapper.PSOBasedMethods.BasicSwarm

getGBest, getGBestFitness, setGBest, setGBestFitness

Methods inherited from class java.lang.Object

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

Field Details

seedValue

private int seedValue

rand

private Random rand

Constructor Details

Swarm

public Swarm(double theta)

Initializes the parameters

Parameters:

theta - the threshold is used to determine whether a feature is selected or not

Method Details

initialization

public void initialization()

This method initializes the position and velocity vectors of each particle in the swarm. Each particle is randomly initialized in the predefined ranges of values.

Specified by:

initialization in class BasicSwarm<Double,Particle>

evaluateFitness

public void evaluateFitness()

This method evaluates the fitness of each particle in the swarm by predefined fitness function. K-fold cross validation on training set is used for evaluating the classification performance of selected feature subset by each particle.

Specified by:

evaluateFitness in class BasicSwarm<Double,Particle>

updatePersonalBest

public void updatePersonalBest()

This method updates the best position (personal best) of each particle in the swarm. Personal best position is updated when the classification performance of the particle's new position is better than personal best.

Specified by:

updatePersonalBest in class BasicSwarm<Double,Particle>

updateGlobalBest

public void updateGlobalBest()

This method updates the global best position (global best) of the swarm. Global best position is updated when the classification performance of any personal best position of the particles is better than global best.

Specified by:

updateGlobalBest in class BasicSwarm<Double,Particle>

updateParticleVelocity

public void updateParticleVelocity()

This method updates the velocity vector of each particle in the swarm.

Specified by:

updateParticleVelocity in class BasicSwarm<Double,Particle>

updateParticlePosition

public void updateParticlePosition()

This method updates the position vector of each particle in the swarm.

Specified by:

updateParticlePosition in class BasicSwarm<Double,Particle>