🚀 go-pugleaf

Mind wrote:
> 
> For the evaluation function am using an (elementary) evaluation   based on
> material balance and some consideration about development , pawn structures
> and king protection : and this is my problem : this evaluation is very
> elementary and making the program playing really bad.
> 
> Am looking for considerations I may include in my evaluation function.
> What is the vealuation function used in today chess prog (gnuchess for
> example). What Am I missing ? any help is very appreciated (articles, web
> refernces, source code).

I listed out some the things Crafty uses it in evaluation
function in the following note of computer chess.

http://www.wretched.demon.co.uk/Chess.htm

Mobility, and centralisation, are two terms you didn't mention,
that feature heavily in most programs.

GNU Chess uses a lazy evaluation, where the material deficit is
larger than any previously seen positional compensation, it
assumes a cut down evaluation function is sufficient to
recognise a position where material has been lost unnecessarily.
I think this will keep.

GNU Chess also recognises specific ending in he evaluation
function, so as to win KBNvK, or to try and evaluate KPvK
quickly.

GNU Chess and Crafty are both available as source, amongst other
engines, if you need more ideas.

> Is there some consideration for the size of the opening book (am using a
> little book : 5 openings) ? Is this really important ?

I think in opening books quality is as important as quantity,
even if you only give it a handful of lines for each side, for
as long as they are well thought out it'll still be playing good
chess. Of course at the higher levels of chess a comprehensive
knowledge of opening positions is necessary to avoid wasting
time reinventing old analysis, at least computers don't tire
whilst rediscovering old opening theory.