Author: rasjid chan
Date: 23:38:24 01/16/04
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On January 16, 2004 at 16:31:17, Robert Hyatt wrote: >On January 16, 2004 at 12:07:00, Tord Romstad wrote: > >>On January 16, 2004 at 10:02:39, Robert Hyatt wrote: >> >>>I would worry about overflow there. >>> >>>IE e4 could be attacked by pawns on d3 and f3, a bishop at d5 with a queen >>>behind it (4 so far), plus two rooks and two knights. That's 8. It just >>>overflowed to zero. Not to mention the promotion problems where there is a >>>third knight or bishop or second queen... >> >>It is not so dangerous if you are just a bit careful about where and how >>you use the information. I use it mostly in the evaluation function, in >>order to compute stuff like mobility, space and king safety. That one >>or two squares on the board are evaluated incorrectly once every hundred >>nodes or so usually does not have any catastrophic consequences. >> >>You are of course right that an SEE based on this simple kind of attack >>tables is not reliable enough to be used to replace a qsearch. For this >>purpose, I use a much slower and more accurate SEE. >> >>Tord > >I was more worried about the actual overflow. IE if this is a char, 8 attackers >appears to be zero. If it is packed into a word, then 8 attackers wraps into >the next char to the left and corrupts that... I think there is no overflow. His BIT0 is the LSB. 8 attacker overflows to pawn attacking so almost it will be true. having 2 queen almost mean game decided. Extra Knights or Bishop has other simple solution.
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