Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: pv score oscillation

Author: Reinhold Gellner

Date: 06:45:52 10/20/97

Go up one level in this thread


On October 20, 1997 at 08:52:02, Chris Whittington wrote:

>
>On October 20, 1997 at 02:29:25, Reinhold Gellner wrote:

>>To eliminate that problem, try increasing the search depth by 2 ply
>>every iteration.
>
>This is a surprisingly well used solution.
>But increasing by 2 each iteration loses much of the advantage of
>iterating (guided search and 'small' incrementally deeper researches).
>You need to jump by two every two iterations, and find a method for what
>to do in the 'gap' iteration.
>
>Its also an advantage for an exchange-evaluator to stop on odd plies,
>rather than even. Its decisions that an as yet untaken piece is actually
>lost will be better taken if the piece is a computer piece (odd ply)
>than a human piece (even ply). Asymetric safety factor skandal for
>Komputers !.
>
>Best then is to jump by 2 ply every two iterations and use a pruning
>function over the final plies that is strong pruning the first iteration
>and weaker pruning the second - then jump two plies again and so on.
>

2-ply-jumping is not neccessarily more stable than 1-ply-steps, because
the jumping "distance" is simply one ply more. If you are doing
sophisticated prunings, e.g. part-ply prunings, together with
part-ply-extensions, then perhaps half-ply-iterations might be worth
considering.

At the moment I can live with smooth oscillations jumping allways one
ply.

Reinhold



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.