Java Word Generator using Genetic Algorithms

by Daniel Booher

This is a Java program, run in the terminal, that generates a target word/phrase using Genetic Algorithms

This program uses ANSI Escape Sequences meaning that Windows Command Prompt (cmd) CANNOT OUTPUT CORRECTLY!

If you are using Windows, there are a number of terminal emulators available that do support ANSI Escape Sequences, the easiest of which to get is:

Windows Terminal

Terms

These are some terms that are necessary to understand in order to use this program:

Target

The word or phrase that the program will try to generate using genetic algorithms

Word

Each Word has the same number of letters as the target word/phrase

Every Word has a fitness based on the letters it contains

Fitness

If a letter in a given Word is the same letter and in the same spot as in the target, it is worth 1 fitness

Fitness for each Word is calculated by summing up each letter's fitness

Example:

target = cat

Word = cac

Fitness = 2 (1 for the c and 1 for the a and 0 for the second c)

Population

A collection of Words used to generate new Words

A Population knows:

The highest fitness within the population

The word that has the highest fitness in the population

The average fitness in the population

Generation

Each Generation a new Population is created

This new Population gets its Words by mutating the Words of the old Population

It does this by picking 2 Words from the old Population as parents and creating a new Word (the child) from those parents

Every child has a 50% chance to inherit a letter from each parent (50% to inherit from parent 1 and 50% to inherit from parent 2)

Every child also has a user determined percent chance to have each letter mutate

A mutation replaces that letter with a random letter and no inheritance happens for that letter

Usage:

java wordGenerator.WordGenerator

If this command does not work, you probably need to define the classpath for the JVM to use.

While in the JavaWordGenerator folder use the command:

java -cp . wordGenerator.WordGenerator or java --classpath . wordGenerator.WordGenerator

It will ask you to input some values:

Population size

The number of words to be mutated in a Population

Population size is an int

Mutation Percentage

The percentage each letter in a given word has to mutate (randomly change to another letter)

Mutation Percentage is entered as an int which is interpreted as a percentage

ex: Mutation Percentage = 10 -> 10% chance for a letter to mutate

Target

The word/phrase that this program will try to generate

is a String and can include A-Z, a-z, 0-9, spaces, and symbols

Example:

Input: java wordGenerator.WordGenerator

Output: Please enter population size

Input: 100

Output: Please enter the percentage for the mutation to occour

Input: 1

Output: Please enter target word or phrase

Input: Hello World

Output:

Generation: 559

Top Word: Hello World

Fitness: 11

Average Fitness: 9.880000

Elapsed time: 0.8557480000000001 second(s)