Author: Bo Persson
Date: 05:14:54 10/20/02
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. > This might be a position where you are to extend you normal search, and *not* go into the qsearch at all. Singuar extension, anyone? Bo Persson bop2@telia.com
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.