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Subject: Crafty source code question

Author: KyoJin Kim

Date: 07:32:51 03/26/98


Hi, Bob!

I try to understand source code of Crafty.
I KNOW BASIC deep alpha beta pruning of negamax searh algorithm.
I have question about this this part of code in search.c.

      if (first_move) {
        value=-ABSearch(-beta,-alpha,ChangeSide(wtm),
                        depth+extensions,ply+1,DO_NULL);
      }
      else {
        value=-ABSearch(-alpha-1,-alpha,ChangeSide(wtm),   <=== ????
                        depth+extensions,ply+1,DO_NULL);
        if (value>alpha && value<beta) {
          value=-ABSearch(-beta,-alpha,ChangeSide(wtm),
                          depth+extensions,ply+1,DO_NULL);
        }
      }

Could you explain to me this part?
Is there any book or document which explanin about this (windows ?) ?

Thank you in advance.



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