Author: Sune Fischer
Date: 02:11:48 08/24/03
Go up one level in this thread
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. 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....? I think it'd be more on the money to say, that the 7th ply of the qsearch is inaccurate. :) -S.
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