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Subject: Re: High NPS vs. Low NPS

Author: Steve Maughan

Date: 04:56:42 11/26/01

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Uri,

Please note I'm not critisising Goliath just using it as an example of a fast
nodes / second engine.

>What do you mean by piece-table evaluation?

The normal definition e.g. a knight on e5 always gets +350 from a pre-computed
table

>Goliath does not use piece-table evaluation

I'd be amazed if it didn't.  The nodes / second are too high for it to be
spending any significant time in the evaluation function.  I guess it's possible
that Goliath doesn't have the definition of nodes / second.

>you cannot evaluate passed pawn only by piece square table and it seems that
>goliath knows to evaluate passed pawns and here is the proof:
>
>goliath can see positive score for white inspite of the fact that it does not
>see the promotion
>
>Goliath Light 1.5 - Blass,U
>7k/7r/2pp4/2p5/2p5/8/PK6/7R w - - 0 1

The example shows that Goliath does know about passed pawns and the squared rule
for them being unstoppable.  In this sense you're right it isn't a *pure* piece
square table engine.  However from the n/s I believe that it must be mainly
piece square table based.  The example you give could be solved using a simple
pawn hash - so I guess that Goliath does a leaf evaluation of pawns coupled with
piece square tables for the other pieces.

>How do you know this information about goliath and chessmaster?
>The source code of Goliath or Chessmaster is not free so the only way that you
>can know is if you talk with the programmers.

Frans Morsch in London 2000 said that Chessmaster evaluated the control of each
square - I don't know from where he found this.  As regards Goliath, I'm
assumming from the nodes / second.

Regards,

Steve



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