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Subject: Re: DB NPS (anyone know the position used)?

Author: Ernst A. Heinz

Date: 19:27:40 01/25/00

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Hi Peter,

>Excuse me for being blunt but let me reformulate
>my point: the NPS rate of a one by one hardware move
>generator that is fed via a general purpose computer
>which forks out the last 4 plies is IMHO basically
>__constant__, since the frequency of FIND-VICTIM,
>FIND-AGGRESSOR, MAKE-MOVE, EVALUATE, UNMAKE-MOVE,
>A-B operations is constant and the software overhead
>on the SP can be ignored since the tree that is
>searched on the SP is (relatively speaking) non
>existant.
>
>So my guess is that you can take the starting
>position or a pawn ending to time the thing. Doesn´t
>matter in terms of nodal rate. Same result.

I exactly understand what you mean but I am not so sure
about your conclusions.

  1.  The static evaluation hardware has "fast" and "slow"
      parts which differ considerably in execution cycles.
      The "slow" part is guarded by a futility-style lazy
      mechanism which leads to differences in execution time
      per node.

  2.  The shape of the search tree itself leads to differences
      in execution time per node because the number of moves
      followed before you get a cutoff varies.

(1) + (2) ==> search speed as measured in nodes per second
              may differ significantly in some positions even
              for chess hardware such as Deep Blue!

=Ernst=



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