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Subject: Re: hanging pieces in rebel

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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