ECJ 10
A Java-based Evolutionary Computation and
Genetic Programming Research System
by Sean Luke

Contributors: Liviu Panait, Jeff Bassett, Robert Hubley, Gabriel Catalin Balan, and Alexander Chircop

ECJ is a research EC system written in Java. It was designed to be highly flexible, with nearly all classes (and all of their settings) dynamically determined at runtime by a user-provided parameter file. All structures in the system are arranged to be easily modifiable. Even so, the system was designed with an eye toward efficiency; ECJ may make you reconsider notions about Java and slowness.

Features

ECJ is pretty full-featured as evolutionary computation systems go, and I believe it to be the most feature-rich GP system available in the public domain.

General Features

• Platform-independent checkpointing and logging
• Hierarchical parameter files
• Multithreading
• Mersenne Twister Random Number Generators
• Abstractions for implementing a variety of EC forms.

• Asynchronous island models over TCP/IP
• Genetic Algorithms/Programming style Steady State and Generational evolution, with or without Elitism
• Evolutionary-Strategies style (mu,lambda) and (mu+lambda) evolution
• Very flexible breeding architecture
• Many selection operators
• Multiple subpopulations and species
• Inter-subpopulation exchanges
• Reading populations from files
• Hooks for coevolution, competitive/cooperative fitness strategies, and multiobjective optimization
• Packages for parsimony pressure

• Set-based Strongly-Typed Genetic Programming
• Ephemeral Random Constants
• Automatically-Defined Functions and Automatically Defined Macros
• Multiple tree forests
• Six tree-creation algorithms
• Extensive set of GP breeding operators
• Seven pre-done GP application problem domains (ant, regression, multiplexer, lawnmower, parity, two-box, edge)

• Fixed-Length and Variable-Length Genomes
• Arbitrary representations
• Five pre-done vector application problem domains (sum, rosenbrock, sphere, step, noisy-quartic)

• Multiset-based genomes in the rule package, for evolving Pitt-approach rulesets or other set-based representations.
• Hooks for using the Teambots robot simultation system to do evaluation.

Download ECJ

Download ECJ version 10 as ec.tar.gz or (bigger) ec.zip. The license agreement and online documentation of the system is also available.

ECJ is released under a special open source license. Please read the license before using the software. See the provided README file to locate the software license.

ECJ is a very extensive system and my experimental needs only rigorously test certain parts of it. I welcome you to try it out and bang on it and improve it. Please contact me with any suggestions, ideas, or modifications.

Migrating from the Previous Version

ECJ10 is bug fixes mostly. One bug fix is particularly crucial with regard to ES: ECJ9's mu,lambda and mu+lambda selection procedures were usually inverted (it picked the worst individuals rather than the best). Hopefully we've got that straight now :-) ... double-check just in case and let us know.

Another bug fix -- well, update really -- is a new initialization algorithm for Mersenne Twister. This puts us in parity with the current MT implementations; however the result is that we are NOT replicable with previous ECJ versions any more. If you need replicability, the previous version of MT is provided in ec/util.

In general, it would be wise to scrutinize the CHANGES file...

The Agent

The software license refers to the "Agent". Presently, that's me, Sean.

Contacting the author

Other Publically-Available Java-Based Evolutionary Computation Systems

GP Systems

Tree-based GP, implemented with trees

• ECJ
• gpsys
• jrgp
• JGProg
• Sutherland (contact Nicholas McPhee)
• Genetic Programming in Java by Russell Wallace

Tree-based GP, implemented with arrays

• javaGPtree, by Steve Furlong

GP Applets

• Symbolic Regression applet by Hansueli Gerber.
• DGP, based on Gerber's applet.
• MTGP (contact A. M. S. Zalzala)

GP using Java Bytecode

• BCGP (contact Brad Harvey)
• JME and DJBGP (contact Eduard Lukschandl)

Private GP Systems

• genetic-programming.com (John Koza's company) has developed a fast Java system.

GP: Whereabouts Unknown

• gpjpp
• gpjava, originally developed at ASyG, Vrje Universiteit Brussel.

Other EC Stuff in Java

This is just a small sample, of course.

• DREAM/ JEO (code here) Quite an extensive grid computing model for doing EC stuff on a big scale. Check it out.
• ECKit, a Java-based system for cooperative coevolution.
• JDEAL (GA/ES)
• JavaSANE (evolving neural networks)
• Java applet showing Evolved Cellular Automata
• GENALG, another GA applet
• Evolvica, a collection of tutorials and applets demonstrating GA, ES, and GP.
• Another GA demo.
• The EA Visualizer (GA)
• Rasjus Ursem's EA Library (GA, a little GP)
• jaga (GA)
• Multiobjective optimization applet
• Various Demonstrations of using Java to evolve nifty stuff
• GASLAB has GA Java tools
• A Java-based demonstration of evolved Traffic control rules, discovered through GP