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Subject: Re: Use of square eval using Bit Boards aka Ed's Rebel Evaluation,but for bb

Author: scott farrell

Date: 04:08:36 01/08/03

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On January 08, 2003 at 05:03:08, Russell Reagan wrote:

>On January 08, 2003 at 04:43:12, scott farrell wrote:
>
>>for (sq=0; sq<64;sq++){
>>  if(  (mask[sq] & whiteQueenAttacks) !=0)
>>    attackers++;
>>  if(  (mask[sq] & blackQueenAttacks) !=0)
>>    defenders++;
>>  ......
>>}
>>if (attackers>defenders)
>>    ATTACK_NOW_!!!!!
>>
>>atleast this method I dont have ot itereate the actuall attack vectors, and
>>avoid slow msb/pop type routines.
>
>If are only interested in the number of attackers, instead of doing a
>64-iteration loop, just do a popcount. It shouldn't be any slower than what you
>are doing above, and it will only take N iterations when there are N attacks on
>the board, so it should always be faster.
>
So I guess you are saying:

whileThereAreMorePieces
  getAttackers().popcount
  getDefenders().popcount

So you iterate the pieces instead of the squares, that is better than I had, but
still a lot of loops.

Scott

>As for using Ed's idea with bitboards, I am interested in this too, but it's
>late and my brain isn't all here, so maybe I'll have some other ideas after I
>get some sleep :)
>
>Russell



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