Computer Chess Club Archives




Subject: Re: Hashing double bounds

Author: Robert Hyatt

Date: 13:55:26 06/20/05

Go up one level in this thread

On June 20, 2005 at 15:18:05, rasjid chan wrote:

>I have implemented hashing 2 bounds after reading fruit does this.
>It is fairly complicated to do and I just want to see if it is done wrongly.
>I measured the figure
>  hash-hit-return-by-2nd-bound/total-hash-hit
>Per game move it is 0.000 almost all the time.
>Ocasionally it has 0.001 and almost rarely 0.002.
>If others have much higher figure then this,I suspect my double-bound is done
>badly. It is difficult to debug except through usual hit statistic.
>If this 2nd bound statistic is correct, then fail-soft propagation
>of exactness is far better. For full-search FL exactness,it starts from 2/3%
>and drops to about 1% for whole game.
>Best Regards

This is more common for mtd(f) programs, since the same position may fail high
one search, and low the next, as the window passes over the true score.  For
non-mtd(f) programs, two bounds is worthless.

This page took 0.01 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.