hcrypto.analyzer.evolutionary
Class WordBasedGaIndividual

java.lang.Object
  hcrypto.analyzer.evolutionary.GaIndividual
      hcrypto.analyzer.evolutionary.WordBasedGaIndividual

All Implemented Interfaces:

java.lang.Comparable

public class WordBasedGaIndividual
extends GaIndividual
implements java.lang.Comparable

Field Summary

java.lang.String	unused_decrypt
java.lang.StringBuffer	unusedLetters
java.lang.String	used_decrypt
java.lang.StringBuffer	usedLetters
java.lang.String	usedLettersNoDups
int	word_count

Constructor Summary

WordBasedGaIndividual(GaIndividual i)
Copy constructor

WordBasedGaIndividual(java.lang.String text, java.lang.String initKey, Dictionary d, GaParameters p)
This constructor takes an initial distribution for the key as a parameter.

Method Summary

void	calcFitness() This method should be implemented in the subclass.
void	cross(GaIndividual i) This version of cross swaps characters from each individual's list of characters used in the words found by each individual's key.
java.lang.String	displayCrossData()
double	evaluate(java.lang.String text, java.lang.StringBuffer usedLetters)
int	mutate(double rate) This version of mutate swaps two random characters in the key.
int	mutateUnused(double rate) This version of mutate swaps two unused characters in the key.
java.lang.String	toString()

Methods inherited from class hcrypto.analyzer.evolutionary.GaIndividual

compareTo, getDecrypt, getFitness, getKey

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Comparable

compareTo

Field Detail

unusedLetters

public java.lang.StringBuffer unusedLetters

usedLetters

public java.lang.StringBuffer usedLetters

usedLettersNoDups

public java.lang.String usedLettersNoDups

used_decrypt

public java.lang.String used_decrypt

unused_decrypt

public java.lang.String unused_decrypt

word_count

public int word_count

Constructor Detail

WordBasedGaIndividual

public WordBasedGaIndividual(java.lang.String text,
                             java.lang.String initKey,
                             Dictionary d,
                             GaParameters p)

This constructor takes an initial distribution for the key as a parameter.

Parameters:

text - -- A string giving the text to be decrypted.

initKey - -- A string giving the initial values for the key.

WordBasedGaIndividual

public WordBasedGaIndividual(GaIndividual i)

Copy constructor

Method Detail

cross

public void cross(GaIndividual i)

This version of cross swaps characters from each individual's list of characters used in the words found by each individual's key. If the OCCURS check is included -- that is, if a check is made to insure that a swap will not negate a key's decrypt of a word -- then this algorithm will guarantee that the children are no worse than their parents at finding words. In experimental runs, approximately half the crosses result in improvements and half in no change. Without the occurs check a very small percentage of all crosses lead to improvement and a slightly smaller percentage produce children that are actually lower scoring than their parents. MODIFICATION: 11/5/02. Added some swapping of unused characters.

Specified by:

cross in class GaIndividual

Parameters:

i1 - an Individual parent

i2 - an Individual parent

mutate

public int mutate(double rate)

This version of mutate swaps two random characters in the key. The mutation is done with frequency equal to rate. The resulting mutant is discarded if it does not improve the fitness of the individual.

Specified by:

mutate in class GaIndividual

Parameters:

rate - is the mutation rate

mutateUnused

public int mutateUnused(double rate)

This version of mutate swaps two unused characters in the key. The mutation is done with frequency equal to rate. The resulting mutant is discarded if it does not improve the fitness of the individual.

Parameters:

rate - is the mutation rate

calcFitness

public void calcFitness()

Description copied from class: GaIndividual

This method should be implemented in the subclass.

Specified by:

calcFitness in class GaIndividual

evaluate

public double evaluate(java.lang.String text,
                       java.lang.StringBuffer usedLetters)

displayCrossData

public java.lang.String displayCrossData()

Overrides:

displayCrossData in class GaIndividual

toString

public java.lang.String toString()

Overrides:

toString in class GaIndividual