L. Dijksman Site
WBEC Ridderkerk, Leo Dijksman's long time tournament.
G. Lyapko Site
George Lyapko's computer chess tournaments and ratings.
CEGT
Chess Engines Grand Tournament, ratings about chess programs.
Arena
A graphical interface for chess engines and news about computer chess.
GSEI Group
Italian site of computer chess programmers.
ASTRONOMY
A.R.A.R
Amateur astronomers of Ravenna, many astro photos available.
BACKGROUND
In May 2006, during the World Chess Championship in Turin a program called "LION" was disqualified because it was recognized as a modified version of Fruit/Toga (which is a strong, open-source chess program). I was there, and I also lost the game against it.
This was not a problem, after all I was there for fun. The problem was the press room of the Chess Olympiad which started to write absurd articles (in italian) against this disqualification. After reading these articles my first reaction was to abandon computer chess.
The second reaction was: "One day most chess program will be open source (well, copyrighted if required)". My two cents in supporting open source chess programs is to publish my sources as well.
TWO YEARS LATER
After the publication of my sources I received some critics: "more sources available means more cloned chess programs". I disagreed because Delfi was 200 ELO weaker then the best programs, so its sources were not a problem.
Bye the way in two years Delfi improved more than 150 ELO, so the problem is now real. For this reason the latest version with source code available is 5.1. The new versions are not available.
LICENSE
The source code of Delfi is copyrighted, the license agreement allows you to:
That's all. Any other use is not allowed. For example you cannot copy parts of Delfi in your applications and you cannot publish new chess programs derived from the Delfi code. Please note that the source code cannot be redistributed, the only legal way to get it is from this web page.
If you don't agree to these terms please don't download!
If you agree, click to download the Delfi 5.1 source code.
TECHNICAL DETAILS
The search function is quite standard: null moves, futility and history pruning, PVS alpha-beta. Some of the rest is quite uncommon and sometimes obscure, this is caused by the assembly code. I will remove some assembly code in the future, since it seems that modern compilers can produce very good X86 code by their own.
The easy levels are not included in this distribution. I guess that the source code can be compiled by any Pascal compiler with inline assembly, I used Borland Delphi 5,6,7,2005,2006,Turbo.