EvoStrat Generation 100 Network Defeats On-Line Opponent!
The same web-based Connect-Four system (Four In A Line) was used to test the
EvoStrat player that uses the neural network from generation 100, and the EvoStrat-evolved
player defeated the
on-line system playing in Medium difficulty mode! This shows that the evolution
was successful in developing a neural-network that can evaluate board positions better
than a randomly-weighted neural network, and serves as proof that the EvoStrat project
effectively uses evolutionary computation to develop a game-playing software agent that
learns from playing tournament after tournament against other machine agents.
For this test game, EvoStrat once again played as the Red player (the player that
To view screenshots of EvoStrat's winning game against Four In A Line, click on these
thumbnails. EvoStrat is the Red
player in both games; Four In A Line is Yellow in one screenshot and Blue in the other.
EvoStrat Generation 0 Network Loses to On-Line Opponent
A web-based Connect-Four game called "Four In A Line" from the website
was used as an opponent for the EvoStrat system. For the initial
test, a random neural network (from generation 0) was used for the EvoStrat player playing as Red
(the player that goes second), and
the EvoStrat player lost to the on-line system when that system was playing in Beginner mode (the
easiest level that the on-line system provides).
To view screenshots of EvoStrat's game and Four In A Line's game (EvoStrat is the Red
player in both games; Four In A Line is Yellow in one screenshot and Blue in the other),
click on these thumbnails:
Next, the on-line system will be used to
test EvoStrat's evolved best player after 100 generations of evolution.
EvoStrat-evolved Player Defeats Young Human Opponents
The first official tests of the Connect-Four players evolved by EvoStrat were conducted
over the Thanksgiving holiday weekend. My oldest nephew (age 6) was an enthusiastic
test subject for the system, and my children (ages 14, 11 and 8) reluctantly particpated as
well. All four test subjects were able to defeat the Connect-Four machine player that
used a randomly-weighted neural network (a network that would make random evaluations of board
positions and therefore make random moves), but the system using a network that was evolved
to generation 100 consistently beat the 6- and 8-year-old
humans, and split several games against the older human test subjects.
EvoStrat program produces results
The EvoStrat system has produced a series of neural-network-based computing agents that
have evolved generation by generation as a result of the tournament selection method
described previously in this project blog. Using a population size of 20 and an
evolution limit of 100 generations, the system has conducted 100 tournaments and evolved
the succeeding generation from the winner of the current generation's tournament using
To view a screenshot that shows the scores of all 20 of the 100th generation of Connect-Four
machine players in their tournament, click on this thumbnail:
The next step is to modify the Connect-Four game program so that the machine-based players
have the ability to load the neural network weights that were generated by EvoStrat into the
Connect-Four game. The machine player will be tested against human players and
against on-line Connect-Four
Network Configuration Chosen for First Connect-Four Testing
To effectively use a neural network to evaluate Connect-Four game boards, the network
must consider the contents of all board spaces. Since a standard game board has 6 rows
and 7 columns, there are 42 inputs that must be fed into the network to ensure that no
inputs are ignored by the system. It is known in the neural network community that
having many intermediate levels of neurons between the input and output layers of the network
does not yield better results, and only slows down processing time when compared to a network
with one or two intermediate layers; as a consequence, the network configuration that is to
be chosen is one with two intermediate layers: the first will contain 50 neurons and the second
will consist of 10 layers. The network will produce one output value, which will be a
double-precision floating point value between 1.0 and -1.0, which will be interpreted as an
evaluation of the board. A value of 1.0 is a strong position for the Yellow player, and
a value of -1.0 strongly favors the Red player; a value near zero is neutral.
Initially, the networks in the first generation will produce random evaluations, and
by the process of tournament selection, networks in later generations will produce evaluations
that approach the interpretation described above. To view a screenshot of the
network's structure, click on this thumbnail:
Tournament Algorithm Implemented and Tested — It Picks the Winner!
The latest test application conducts a tournament among all members of the current population
of Neural Networks, with each network playing 5 games as the Yellow player (who goes first)
against randomly selected opponents playing Red. The test of the tournament algorithm
doesn't actually play a game of Connect-4; each game for this test is just a random coin-flip
to determine the winner. The purpose of this testing is to see if total game points can
be tracked for each population member and the winner of the tournament can be tracked.
For this test, the winner of a match earns 3 points and the loser earns -4 points.
Since each network might play a different number of games as the red player, the total points
earned are divided by the number of games played, and the winner of the tournament is the
network with the highest average points per game played. The test program correctly
determines the winner, and so this algorithm will be employed when the Connect-4 players are
implemented in the next step in this project. To view a screenshot of the
output of the test program, click on this thumbnail:
Next Step: Conducting a Tournament to Pick a Winning Network from Each
The success of the test implemented last night is just a milestone on the path to having
a Machine Connect-Four player be able to evaluate game board configurations and choose
moves. A crucial difference between simple neural network pattern recognition
tasks and the type of game board evaluation needed for EvoStrat is that there is no
known "best" or "ideal" answer for a particular encoding of a game board state. To
train the networks to be used by EvoStrat, a tournament will be held, pitting members
of the generation against one another, and the winner of the tournament will be judged
as the best member of its generation.
The tournament will be conducted as follows: each of the members of the population
will play 5 games as the yellow player (who makes the first move in every game),
against a randomly-selected opponent who will
play red. The expected number of games that any member of the population will play
as red can be computed to be 5, so on average, each network will play 5 games as the
yellow player and 5 as the red player. The next stage of this project will be to
implement a tournament-playing algorithm to pit networks against each other and choose the
"best" member of the generation by the results of the tournament. Stay tuned....
Simple Genetic Algorithm for Neural Network Learning Works!
After a fair amount of reading manuals, javadocs and on-line documentation, Encog 3 has been
utilized to implement a test program that establishes a population of
20 initially-random neural networks, and uses competitive techniques to evolve generations
networks that get better and better at the task of recognizing a
simple two-input pattern. This is a proof-of-concept test that shows that Encog 3
can be used to
represent the neural networks that will be used in EvoStrat to evaluate
the game state of a particular
game board configuration. To see Java code that implements the genetic algorithm
to evolve the population through numerous generations, or to view a screenshot of the
output of the test program, click on one of these thumbnails:
Encog 3 Chosen for Neural Network Implementation;
(from Heaton Research)
The Machine players for this project need to evaluate Connect-Four game boards and
choose the best move from among all possible moves. To do this, the Machine players will
implement a neural network that evaluates game boards. After researching available
neural network open-source software, I've decided to use the Encog 3 machine learning framework
for Java, from Heaton Research
(http://www.heatonresearch.com). Using an off-the-shelf software library
will save the time it would take to code the details of
neural network implementation myself, and allow me to focus on using the neural network in
determining the best moves to make at any one point in a game.
Working Version 2 Ready for Testing
A game trace area has been added to the interface so that the moves of the game can
be recreated after the game has concluded. Moves are now correctly counted, and illegal
moves made by a Human player are properly disallowed. At this stage, the Machine players
still make random moves, and are very easy to defeat. To play this version, click on
System Supports Machine vs. Machine Play
If Machine vs. Machine play is selected on the start-up screen of the program, a game is played
by the two artificial agents against one another, and the final results are displayed on
screen when the game has ended. At this point, the test agents are both random players, so
the moves made are generally awful if one examines the Connect-Four board, but the point of this
testing is that Machine vs. Machine play is now supported by the game engine.
Human vs. Machine Play Now a Reality
The main interface has now been developed to the point that a Connect-Four game can be
played in one of several modes: Human vs. Human or Human vs. Machine (where the
first move can be made by either the Human player or the Machine player). For testing
purposes, the Machine player simply chooses a column in which to drop a piece at random, so
it's really easy for a Human to beat. But it is a good demonstration that Human vs.
Machine play works with the current system. Now it's time
to get some sleep!
First Step: A Working Connect-Four Game
Before starting work on the evolutionary aspects of the artificial agents for
this project, a working Connect-Four game is needed for testing purposes.
Accordingly, the first coding that been completed is for a Java Application that
allows two human players to compete in a game. This platform will be expanded with
the ability to have a human play against a machine opponent, as well as having two
machine agents play against each other. For a full-size screen-shot of the first
version of the game interface, click on this thumbnail:
Partial Class Diagram: The Player Class and Descendants
I feel it is important to model good programming practices while working on this project,
and as a consequence, I intend to use object-oriented design techniques to structure the
code for the software components of EvoStrat. As a first design step, I plan to
use inheritance to structure the game players for the system: each of the two players
will come from the Player class, and each specific player can be either a
HumanPlayer or a MachinePlayer. The game engine will expect
to work with two Player objects, and the specifics of making moves will be different
based on whether the player is a human or a software agent. Click on this thumbnail to see
a partial UML class diagram for this inheritance situation:
Mid-Summer Progress Update
Well, today is July 1, and I've done a lot of virtual work on EvoStrat (in other words,
thinking about it), but I haven't really started in on the design and programming work
yet. I'm planning to evaluate several artificial neural network programming
libraries over the next two months, and be ready to hit the ground running right after
Labor Day. I plan to post updates to this site weekly during the fall of 2013, so
keep checking back for the latest news on this project.
First Press Release Developed
The EvoStrat Project won't get fully underway until the summer of 2013, but as an example
for the Spring 2013 CSC 492 course at the University of Mount
Union (titled The Practice of Software Engineering), a sample
press release announcing the project has been developed and may be accessed
from this link. More sample documents
may be developed during the Spring semester, as time permits.
Initial Project Timeline Released
The first draft of a project schedule for EvoStrat has been posted to the project web site. Use the "Timeline" navigation item at the top of the screen for the latest details.
Welcome to EvoStrat!
You've arrived at the web home of EvoStrat, software that uses bio-inspired computing techniques to evolve strategies for games with no initial knowledge of the games themeselves. Use the navigation links at the top and/or right-side of this page for more information on this project. This site will be updated regularly as the project develops.