edu.udo.cs.yale.operator.features.construction
Class FourierGenerator

java.lang.Object
  edu.udo.cs.yale.operator.features.IndividualOperator
      edu.udo.cs.yale.operator.features.construction.FourierGenerator

All Implemented Interfaces:

PopulationOperator

public class FourierGenerator
extends IndividualOperator

This PopulationOperator generates new attributes in an individual's example table. Each piecewise continous function can be synthesized with help of a Fourier synthesis, i.e. with a sum of trigonometric function with different frequencies and phases. This pop op searches for the best frequencies and construct the corresponding trigonometric functions as new attributes. For each attribute a of the individuals the following is done:

1. The label is seen as function of the attribute a
2. A fast fourier transform is performed to search the k biggest frequencies f_kin this attributes space (and their phase differences p_k).
3. For each of these k frequencies a new attribute is generated: sin(f_k * a) + p_k.

Version:

$Id: FourierGenerator.java,v 1.4 2006/08/03 14:39:36 ingomierswa Exp $

Author:

Ingo Mierswa

Field Summary

private int	applyInGeneration
private SinusFactory	factory The sinus factory.
private RandomGenerator	random
private int	startGenerations

Constructor Summary

FourierGenerator(int maxPeaks, int adaptionType, int attributesPerPeak, double epsilon, RandomGenerator random)
Creates a new fourier generator.

Method Summary

java.util.List<Individual>	operate(Individual individual) Subclasses must implement this method providing a list of new individuals.
boolean	performOperation(int generation) The default implementation returns true for every generation.
void	setApplyInGeneration(int applyInGeneration)
void	setStartGenerations(int startGenerations)

Methods inherited from class edu.udo.cs.yale.operator.features.IndividualOperator

operate

Methods inherited from class java.lang.Object

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

Field Detail

factory

private SinusFactory factory

The sinus factory.

startGenerations

private int startGenerations

applyInGeneration

private int applyInGeneration

random

private RandomGenerator random

Constructor Detail

FourierGenerator

public FourierGenerator(int maxPeaks,
                        int adaptionType,
                        int attributesPerPeak,
                        double epsilon,
                        RandomGenerator random)

Creates a new fourier generator.

Method Detail

setStartGenerations

public void setStartGenerations(int startGenerations)

setApplyInGeneration

public void setApplyInGeneration(int applyInGeneration)

performOperation

public boolean performOperation(int generation)

Description copied from class: IndividualOperator

The default implementation returns true for every generation.

Specified by:

performOperation in interface PopulationOperator

Overrides:

performOperation in class IndividualOperator

operate

public java.util.List<Individual> operate(Individual individual)
                                   throws java.lang.Exception

Description copied from class: IndividualOperator

Subclasses must implement this method providing a list of new individuals. individual will be removed from the population so it might be useful to return a list of size 1 containing only the modified individual. If the original individual should also be part of the new population it must also be added to the result list.

Specified by:

operate in class IndividualOperator

Throws:

java.lang.Exception