Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: A question about quiescence search

Author: Antonio Dieguez

Date: 20:45:20 10/19/02

Go up one level in this thread


On October 19, 2002 at 22:02:53, Nagendra Singh Tomar wrote:

>On October 19, 2002 at 21:22:57, Antonio Dieguez wrote:
>
>>
>>>I believe we do qsearch to see if there are any hidden surprises (a solution for
>>>the horizon effect). So the objective of doing a qsearch is to find whether the
>>>current positions score is really what we think or whether there is a big
>>>surprise which pulls it down drastically. So if we assume that the score is at
>>>least the static score then we are losing the advantages of qsearch, the reason
>>>at first place why we opted to do a qsearch
>>
>>'cuse me.
>>
>>what happens if there are no captures, you return the static score (I
>>suppose...) and clearly if the side to move has available captures then the
>>thing could only get cooler for it
>
>Not always..
>At least not for forced-capture cases. let me explain forced capture. Suppose at
>the end of the extensive search (qsearch root)
>we have our rook(trapped or pinned to a higher value piece so that it is
>immobile) and suppose the
>opponent's pawn is attacking it. The attacking pawn is also guarded by another
>pawn. The only way for us to avoid losing our rook is to capture the atatcking
>pawn by say our knight. This is a forced capture. now in the next move the
>opponents other pawn will take our knight so we lose our knight to the
>opponent's pawn. In this case the capture is leading to a worse score than the
>static score.
>We can have many such cases during the search. Rook and pawn are just symbolic
>of a high value and low value piece.

you are completely right in what you mean. Personally I get out of the qsearch
in a few cases only sometimes when a pawn is attacking a piece, or a horse
attacking a rook or queen, or a bishop at.a rook on a corner, or a rook at.a
queen at b2/g2/b7/g7. That is something minimal to do though, I suposse there is
nothing so great to do in the qsearch anyway because that is the reason for the
main fullpowered search. At least one could add all the cases when there are a
piece enprise, but I didn't like that when I tried(so often not affecting in
nothing, except taking more time to reach depth)

seeyou.



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.