Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: How important are hashtables?

Author: Stuart Cracraft

Date: 10:34:08 12/27/05

Go up one level in this thread


On December 27, 2005 at 04:49:51, Vasik Rajlich wrote:

>On December 26, 2005 at 16:52:23, Jonas Cohonas wrote:
>
>>For long analysis that is, i mean if you have an engine running for say 2 days
>>on a position, will it come to another conclusion whether you use 32Mb hash or
>>2Gb hash?
>>
>>In other words will it, at that time control/analysis matter what hash size you
>>use?
>
>I vaguely remember some tests which suggest that every doubling of the hash size
>gives 5 or 6 rating points.
>
>Vas

Yes - I recall something from Gordon Goetsch and Hans Berliner at CMU quite
some time ago that gave 2x = 8 rating points. It may have been Carl Ebeling.
I believe it was the 1970's or 1980's for that figure. And that may have been
USCF rating points instead of ELO points.

Here is a more recent commentary from 1998 SSDF which gave 4-5 rating points
per doubling.

http://www.geocities.com/CapeCanaveral/Launchpad/2640/ssdf/1998/ssdf9804.htm

And here:

http://www.chessassistance.com/Articles/020_Hash_size.html

It is no quick way to improved rating unless the table is horribly small already
of course.

I like to size the table commeasurate with the size of searches I'm doing. Since
I don't size dynamically but statically at compile time. I am sure most size
dynamically at compile time for flexibility. I haven't done this yet.

Stuart



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.