Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Ups, text this time.

Author: Robert Hyatt

Date: 17:17:06 11/28/00

Go up one level in this thread


On November 28, 2000 at 15:58:31, Mogens Larsen wrote:

>On November 28, 2000 at 13:44:15, Robert Hyatt wrote:
>
>>I don't have any "suspicious speculation" in this case.  Only a strong feeling
>>that "right move, wrong reason" is not convincing me of very much.  IE on ICC
>>the other night we had a long discussion about a move Crafty had played.  The
>>GM (Don't remember who it was not, but not Roman) said "Rd4 was beautiful...
>>I am very impressed that the program saw it as it led to a crushing position
>>for it."  I looked at the log and told the group discussing this "The score was
>>very bad for it at that point...  it actually thought that move was best, but
>>that it was losing the game... until it failed high on the 'pondering search'
>>after playing it."  We all agreed that it was just "lucky" there that it found
>>a move that turned into a win, even though it had no idea when it played it how
>>it would turn out...
>>
>>That was my point.  Yes it played the right move.  No it didn't understand
>>why.  It played it fully expecting to lose.  It could have played any of
>>_several_ moves and _still_ expected to lose.  It just _happened_ to pick the
>>right one.  In this case, for a reason (weak opponent pawn) that had _nothing_
>>to do with how the game actually progressed and was won by that move.
>
>The problem with this argumentation is that "right reason" only holds if you're
>able to distinguish between moves by a rising score at a shallow depth. So it's
>basically useless in most cases. Crafty played Rd4 because it evaluated the move
>as being best. Labelling the reasons as either wrong or right for the chosing
>the initial move is wrong.
>
>If the PV at the time of the move was close to what happened in the game then I
>consider it to be chosen for the right reason, even though the score may have
>been inaccurate due to insufficient depth.
>
>Either way, using human perception of "right" and "wrong" reasons based on score
>alone is very simplistic and useless IMHO.
>
>Mogens.


Obviously I don't suggest _only_ relying on the score.  My earlier comments
on the "gambit tiger sacrifices" should dispose of that idea quickly.  The
_right_ PV is convincing.  The right score might be convincing.  The right
move _and_ a reasonable score is convincing.  The only exception is that the
right move, wrong PV, wrong score is _not_ convincing at all...



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.