Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Unique nodes, en passant and perfect hashing

Author: Andreas Stabel

Date: 07:59:39 11/25/99

Go up one level in this thread


On November 25, 1999 at 10:11:58, Ulrich Tuerke wrote:

>I find your results very interesting.
>
>What puzzles me, is the large branching ratio from one iteration to the next one
>which you obtained. I'd thought, that you get a factor of 4 to 5, provided you
>have a resonable move ordering, whereas you have factor of ~20. Could it be that
>your move ordering is very poor ?
>
>I assume, with an improved move ordering, the effects, which you have observed,
>will also become less drastic.
>
>Nevertheless, it might be worthwhile to try your suggestion regarding en
>passant.
>
>Thanks,
>Uli

Remember that this is NOT a chess playing program, only a pure tree scanning
one. To get a branch factor of 4 to 5 you need an evaluation and an alpha-
beta algorithm which I don't have in this system.

Your observation that alpha-beta and a good evaluation and move ordering
will reduce the effects I have found is of course correct. But I still
think clearing the en passant target square when it is not necessary is
so simple that it may have an effect on the speed of a chess program.

Regards
Andreas Stabel



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.