Re: Searching simple opensource chess program

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