Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Static Exchange Evaluation Question

Author: Frank Schneider

Date: 05:02:16 01/24/99

Go up one level in this thread


On January 24, 1999 at 06:51:45, Steve Maughan wrote:

>I understand the basic idea behind SEE is to evaluate the material outcome of a
>position without searching - however I have some questions
SEE tries to evaluate the outcome of a series of exchanges on one square.
It is usually used during quiescence to guess if a capture makes sense.

>
>1 What algorithms are used to do this?  It looks none-trivial since one cannot
>look at a single piece and decide whether or not it will be captured as you may
>also have a more valuable piece en-prise.
Have a look at (for example) Crafty, I think it is in the file swap.c.
Without searching or moving pieces you
simulate a series of exchanges (every capture has the same destinationsquare).
A minimax-like method is used to compute a score for the first capture.

SEE is not perfect since it doesn't do a search and (usually) doesn't detect
for example that a pinned piece can't move.
I once added recognition of pins (to the king), but it was slower and did
influence the searchresults only a little.

>
>2 With 1 in mind - do you believe the SEE outcome enough to back the score up to
>root or simply as an indication of moves to search further?
>
>3 Are there any alternatives?  Does 'everyone' use SEE?
I think using SEE is a good idea. It helped Gromit a lot.

>All help greatly appreciated!
>
>Regards
>
>Steve Maughan
Frank Schneider



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.