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Subject: Re: crafty 16.3 - something broken in K and P endgames?

Author: James B. Shearer

Date: 21:24:59 02/01/99

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On January 31, 1999 at 10:43:10, Robert Hyatt wrote:

                      <snip>
>
>No idea why it takes 16 plies however... but I'll look...
>

     A big part of the reason is crafty 16.3 is far too optimistic about g5.
This can lead to the positions like that shown below which crafty scores -2.35.
This is quite optimistic considering that material is even and the position is a
dead draw.  Crafty 15.15 scores this position -1.19 (see below) which is still
optimistic but better.
                               James B. Shearer
Crafty v16.3

White(1): in fit40a
White(1): setboard 8/8/4p1k1/1p1pP1p1/p2Pp1P1/P1P5/1P2K3/8 b - - 0 40

       +---+---+---+---+---+---+---+---+
    8  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    7  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    6  |   |   |   |   | *P|   | *K|   |
       +---+---+---+---+---+---+---+---+
    5  |   | *P|   | *P| P |   | *P|   |
       +---+---+---+---+---+---+---+---+
    4  | *P|   |   | P | *P|   | P |   |
       +---+---+---+---+---+---+---+---+
    3  | P |   | P |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    2  |   | P |   |   | K |   |   |   |
       +---+---+---+---+---+---+---+---+
    1  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
         a   b   c   d   e   f   g   h

Black(1): exit

Black(1): display
Black(1): score
end-game phase
              clearing hash tables
note: scores are for the white side
material evaluation.................   0.00
development.........................   0.00
pawn evaluation.....................  -0.75
passed pawn evaluation..............  -0.40
passed pawn race evaluation.........  -0.50
interactive piece evaluation........  -0.70
total evaluation....................  -2.35

Crafty v15.15

White(1): in fit40a
White(1): setboard 8/8/4p1k1/1p1pP1p1/p2Pp1P1/P1P5/1P2K3/8 b - - 0 40

       +---+---+---+---+---+---+---+---+
    8  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    7  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    6  |   |   |   |   | *P|   | *K|   |
       +---+---+---+---+---+---+---+---+
    5  |   | *P|   | *P| P |   | *P|   |
       +---+---+---+---+---+---+---+---+
    4  | *P|   |   | P | *P|   | P |   |
       +---+---+---+---+---+---+---+---+
    3  | P |   | P |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
    2  |   | P |   |   | K |   |   |   |
       +---+---+---+---+---+---+---+---+
    1  |   |   |   |   |   |   |   |   |
       +---+---+---+---+---+---+---+---+
         a   b   c   d   e   f   g   h

Black(1): exit

Black(1): score
end-game phase
              clearing hash tables
note: scores are for the white side
material evaluation.................   0.00
development.........................   0.00
pawn evaluation.....................  -0.39
passed pawn evaluation..............  -0.40
passed pawn race evaluation.........   0.00
interactive piece evaluation........  -0.40
total evaluation....................  -1.19



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