Author: Omid David Tabibi
Date: 04:53:07 08/24/03
Go up one level in this thread
On August 24, 2003 at 07:35:12, Sune Fischer wrote: >On August 24, 2003 at 06:35:45, Omid David Tabibi wrote: >>>Like Uri suggested you can first check if the square of the attacker is attacked >>>by a sliding piece, if not no need to look behind it as it can't expose >>>anything. >> >>Sure, but what do you do if you find that an attacker is attacked by a sliding >>piece? How do you incorporate that attacker with the lookup table's result? >> >>For example, there are a number of attackers who attack a square, and a number >>of defenders; the lookup gives the value -3, i.e., a losing capture. Also assume >>that there is an x-ray queen behind one of your attacking pieces. How do you >>incorporate that queen into that -3 value? >> > >Hmm you have not understood completely how the table works I think. I have understood that the tables don't work in such cases :) >As Uri also did point out, a table lookup for SEE doesn't work with this ploy. > >I'm not sure such a table can even be constructed, one could compute the number >of bits theoreticly required by a crafty type SEE. >I suspect such a table would be huge. > >>>I also don't fully agree that qsearch is all about inaccuracies, think about it, >>>all branches terminate in a qsearch, so everything sent down the tree must be >>>garbage....? >> >>Until a while ago at least, Junior did not have any quiescence search at all... > >I think quiescence is too broad a term to say it didn't, every program faces a >quiescence problem at the leaves, so it must have done something. Static SEE analysis at depth = 0 nodes... > >>Besides, even an "accurate" SEE isn't accurate at all: > >I would describle SEE as being accurate, possibly overkill if anything. > >However in my book "accurate" does not mean flawless or perfect, it means >"pretty darn good". "pretty accurate" might be more precise :) > >>3r2k1/pp1n1ppp/2p2q2/8/2PR4/2B5/PPQ2PPP/6K1 w - - 0 1 >> >>SEE will deem Rxd7 a losing capture, while it's actually a winning one. If you >>want a more accurate quiescence, use MVV/LVA. > >No perfect scheme exists, chess is too complex for that (that is why we do the >search in the first place:). >It's just a matter of optimizing the speed vs. accuracy design. > >-S.
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.