Author: Omid David Tabibi
Date: 03:35:45 08/24/03
Go up one level in this thread
On August 24, 2003 at 05:11:48, Sune Fischer wrote: >On August 24, 2003 at 02:27:59, Omid David Tabibi wrote: > >>On August 23, 2003 at 19:55:31, Sune Fischer wrote: >> >>>On August 23, 2003 at 19:35:22, Omid David Tabibi wrote: >>>>> >>>>>Yes you can do that, if you don't need to know where the attacks came from. >>>>> >>>>>It won't be a super accurate SEE, for how do you do x-ray attacks using that? >>>> >>>>And how do you do it accurately using your 32 bit per square scheme? >>>> >>> >>>You get the map of "primary" attackers by the lookup, I still scan behind them >>>the most primitive way to see if there is x-ray attackers. >> >>But how do you incorporate that x-ray attacker with the lookup's result? You >>cannot just add its value to the lookup result... > >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? > >BTW gave some more thought to the squares vs indices table. >It dawned on me, that a square table would not need twice the space but four >times the space, it would be 64x64 rather than 32x32. >There might also be a problem keeping track of the pieces with the square table, >the pieces have a tendency to jump around so you'd never know where their attack >board was and it would be complicated to xor out with the old one. > >Giving each piece a permanent ID-tag makes it easier to track that idividual >piece, ie. where was that piece 5 moves ago, has it been an active piece... and >so on. > >>>I just don't see a quicker way, do you? >> >>Maybe ignoring x-ray attackers altogether?! After all, quiescence search is all >>about inaccuracies, isn't it? (disclaimer: I have not tried this idea yet :) > >If it was just for move ordering I wouldn't question it for a second, but can >you still cull the losing captures using this? >It seems to me it would be wrong very often. > >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... Besides, even an "accurate" SEE isn't accurate at all: [D]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. > >I think it'd be more on the money to say, that the 7th ply of the qsearch is >inaccurate. :) > >-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.