🚀 go-pugleaf

RetroBBS NetNews Server

Inspired by RockSolid Light RIP Retro Guy

Article View: gnu.chess
Article #1094

Re: Searching simple opensource chess program

#1094
From: -nospam-
Date: Sun, 19 Dec 2004 19:22
52 lines
3679 bytes
Paul Pichota wrote:

> For a university project I want to compare different algorithms 
> (minimax, alpha-beta and some variants). So I am looking for rather 
> simple and working opensource program where I can easily exchange the 
> algorithms.

I have tried the same stuff but I came to following conclusion: In order 
to evaluate an algorithm you have to cross-check the results with the 
results obtained from a brute-force search.  The brute-force attack must 
come to a position where the score is agreed with all parties involved.

This has 3 major drawbacks.

1) Brute force search in chess is very time consuming.  Move generation 
is complex and takes a lot of time if a large tree is to be searched. 
(e.g. if you try the go game, you will understand where the compexity lies.)
2) A definite chess score is obtained in the same chess program in the 
evaluation function.  When comparing the chess score obtained with other 
chess programs or a human evaluation, scores may vary.  Only mate and 
technical draw positions are definite.
3) Before all rules (ep, 50moves, 3 fold-repetition) are implemented, it 
takes a lot of time and effort.  Effort that does not contribute to the 
algorithm development.

So in order to compare different algorithms, I designed a program with 
different algorithms and different games.  The only thing you have to do 
is to select the algorithm, and the game-ruleset.  Because of the 
complexity of a chess program, it is left out however.  But I did 
include checkers, connect 4, tictactoe, draughts, othello/reversi... 
etc.  I also implemented different algorithms and you can ask for a move 
to be generated with all algorithms in parallel.  You can easily compare 
the output from minimax/brute-force/alpha-beta/negascout.  It is called 
strategicgames.

 > I have already tried GNU Chess but the search routine is rather
 > complex because of various prunings, heuristics etc.

I can send you the source of my chess program named 'Belofte'.  I can 
assure you, it is much simpler than gnuchess.  You can test playing 
against it on freechess.org.  Finger belofte for more details.  Mail me 
for getting the source code.  www.internetcontact.be/~macchess

You can also download the source code of the strategic games.  It can be 
downloaded from users.telenet.be/artificialintelligence.

PS: Strategic Games does have some errors in the negascout and the 
move-generation for some checkers variants.... Feel free to correct.

Good luck,

Yves
Technical Details
Message-ID: <Yxkxd.4742$aJ2.243774@phobos.telenet-ops.be>
Path: arc1-ca.pugleaf.net!g2news1.google.com!news3.google.com!news.glorb.com!wns14feed!worldnet.att.net!204.71.34.3!newsfeed.cwix.com!ossa.telenet-ops.be!phobos.telenet-ops.be.POSTED!not-for-mail
References: <mailman.6866.1103305323.27204.info-gnu-chess@gnu.org>

Show Full Headers
Complete Article Headers
X-Google-Thread: 10d71d,dc7f62bb0eb67e1f
X-Google-Attributes: gid10d71d,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: arc1-ca.pugleaf.net!g2news1.google.com!news3.google.com!news.glorb.com!wns14feed!worldnet.att.net!204.71.34.3!newsfeed.cwix.com!ossa.telenet-ops.be!phobos.telenet-ops.be.POSTED!not-for-mail
From: -nospam- <-nospam-@telenet.be>
User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.7.3) Gecko/20040910
X-Accept-Language: en-us, en
MIME-Version: 1.0
Newsgroups: gnu.chess
Subject: Re: Searching simple opensource chess program
References: <mailman.6866.1103305323.27204.info-gnu-chess@gnu.org>
In-Reply-To: <mailman.6866.1103305323.27204.info-gnu-chess@gnu.org>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Lines: 52
Message-ID: <Yxkxd.4742$aJ2.243774@phobos.telenet-ops.be>
Date: Sun, 19 Dec 2004 19:22:32 GMT
NNTP-Posting-Host: 81.83.113.178
X-Complaints-To: abuse@telenet.be
X-Trace: phobos.telenet-ops.be 1103484152 81.83.113.178 (Sun, 19 Dec 2004 20:22:32 MET)
NNTP-Posting-Date: Sun, 19 Dec 2004 20:22:32 MET
Organization: Telenet Internet