Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: How many commercial programs use the Brute Force instead of selective ?

Author: Bert van den Akker

Date: 12:44:09 11/19/00

Go up one level in this thread


On November 19, 2000 at 10:19:44, Uri Blass wrote:

>On November 19, 2000 at 09:10:12, Bert van den Akker wrote:
>
><snipped>
>>I think a brute force program with only null move pruning added is at least
>>100 elo points stronger the pure brute force program because it will
>>search 1 or 2 ply deeper.
>
>There are lines that you are going  to see deeper without null move because null
>move pruning prunes them so you cannot use the difference in plies in order to
>calculate the difference in rating.
>
>The only way to know is by playing games.
>
>Uri

In this respect you are right.
But there are also lines which you will see deeper with null move pruning
because the general search will be deeper.


My experiments with null move pruning shows that null move pruning
can cut 90 to 95% af the search tree. In general some combinations
are seen 1 or 2 plies later with null move pruning but this can be compensated
with threat and other extensions and the fact that you are searching 2 plies
deeper in the same time.
A bigger problem with null move pruning is that moves whitch gives subtile
positional advanges can be pruned because  of the nature of the null move
method.

So making a very advanced positional evaluation makes not mutch sense if you
don't make some provisions.

Maybe this is the reason why in the null move pruning is not used.

BvdA



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.