Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Shredder's bug?

Author: Omid David Tabibi

Date: 06:05:42 12/21/03

Go up one level in this thread


On December 21, 2003 at 08:53:39, Jaime Benito de Valle Ruiz wrote:

>I've never read any thread about this before, so forgive me if this is a
>recurring topic.
>Many people have noticed that the Principal Variation shown by Shredder is
>sometimes ridiculous, to the point of giving out its queen and a rook for
>nothing, or allowing a silly mate.

My understanding is that unlike most other engines when failing high or low
Shredder does display a full PV extracted from hash tables (whereas other
engines just show the first move). These moves have naturally bounded scores,
and so are not reliable. That is also one of the main problems in extracting PV
using MTD(f) search. But other than that, Shredder's PVs are accurate.


>If this is “really” what Shredder is
>thinking, then I’m truly surprised that it’s such a strong engine… considering
>that it chooses absurd lines that lead to self-destruction. My engine sometimes
>does something similar, and I’m sure it’s a bug, because the final static
>position of the PV does not match the score is showing anyway (I have other
>things to correct before the PV at the moment anyway), and neither does for
>Shredder.
>Is this a really a bug, or just a trick to conceal the way engine is doing the
>internal search? Because I don’t believe that those PVs are the ones Shredder is
>using for analysis, and still play decent chess.
>What do you think?
>
>  Jaime Benito



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.