Computer Chess Club Archives




Subject: Re: Zero-width Window Null Move Search

Author: Dezhi Zhao

Date: 01:14:16 06/16/98

Go up one level in this thread

On June 15, 1998 at 12:41:26, Ren Wu wrote:

>I did some experiments on this a while back, maybe 2 years ago, both on my chess
>program and my chinese chess program. I can't remember the exact result, but the
>experiment itself make me decide use  alpha, beta, instead a null window.
>I used to use PVS but switch to NegaScout some time ago, but after that
>experiment. So my result is from PVS and is agree with yours here.
>What is your  "vapor-ware" story all about? I think i miss that post.
>BTW what is your program's strength? what is its speed(nps)?
>Ren (

I am happy that you share the same experience and results with me.
Here is the "vapor-ware" story:  When I compared NegaScout to PVS, I found
the savings are virtually negligible (only hundreds of nodes per 3 millions).
I post the results to Crafty mailing list ( and got responses
from Dr. Hyatt  and Vincent Diepveen. They had simliar test results. Vincent
mentained that PVS is the best. And Dr. Hyatt thought that the negligible
savings is not worth the additional structral complexity NegaScout imposes
to the search, and that it seems to be a "vapor ware".  I think it is a
expression, even for a Chinese like me.

My program is still under construction. I think it is now in Expert level.
It can easily beat average players without opening book and pondering.
Currently it searches around 100K nps on Pentium plain 133.
I have a long to-do-list. I'm not as opmistic as I was when starting this
personal project with a goal of Master level.
I am a great believer in bitboard approach. However Chinese chess
has a board of 9*10 squares instead of 8*8.  I am now fighting the arcane
rules of reptition which are not easily and correctly handled as you know.

Tell me something about your Chinese chess program. The best commercial
program as I know is a product of T-Time Co in Taiwan.  Are you  one of
the authors?

PS: I often play at a Free Xiangqi Server, u can visit
my account is dzhao.

Best Regards

Dezhi Zhao

This page took 0.03 seconds to execute

Last modified: Thu, 07 Jul 11 08:48:38 -0700

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