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Subject: Re: Tournament update(about crafty)

Author: Robert Hyatt

Date: 14:10:18 01/13/99

Go up one level in this thread


On January 13, 1999 at 01:41:36, blass uri wrote:

>
>On January 13, 1999 at 00:51:36, blass uri wrote:
>
>>
>>On January 12, 1999 at 06:24:20, Enrique Irazoqui wrote:
>>
>>>Hiarcs 7 - Shredder 3, 6-4. Next match, Shredder 3 - Junior 5.
>>>
>>>Two PII-400/256, auto232, 40 moves in 40 minutes.
>>>
>>>        H7   J5    M8   T11   F532 R10    F5  N99a   G6   CR   S3   TOTAL    Elo
>>>H7(*)  ---   4    3.5    4    4.5   7     8   6.5    8   7.5   6   59.0/100   57
>>>J5      6   ---    6    6.5   5.5   5    4.5   5    3.5  8.5       50.5/90    41
>>>M8     6.5   4    ---   5.5   3.5  5.5    5    7    6.5   7        50.5/90    41
>>>Ti      6   3.5   4.5   ---    5    6    5.5  6.5    6    7        50.0/90    37
>>>F532   5.5  4.5   6.5    5    ---   4    4.5   5     7    7        49.0/90    30
>>>R10     3    5    4.5    4     6   ---   5.5   5     6   5.5       44.5/90    -2
>>>F5      2   5.5    5    4.5   5.5  4.5   ---   4    5.5   8        44.5/90    -2
>>>N99a   3.5   5     3    3.5    5    5     6   ---   5.5  6.5       43.0/90   -12
>>>G6      2   6.5   3.5    4     3    4    4.5  4.5   ---   4        36.0/90   -61
>>>CR(**) 2.5  1.5    3     3     3   4.5    2   3.5    6   ---       29.0/90  -114
>>>S3      4                                                     ---   4.0/10   -24
>>>
>>>(*) A beta version of Hiarcs 7 with an alpha opening book played in the matches
>>>against Junior 5, Tiger 11.7.5, Mchess 8, Rebel 10 and Fritz 5.
>>>
>>>(**) Crafty 16.1 is playing as an engine for Nimzo 99. Because of a bug in the
>>>interface, Crafty clears its hashtables after every move it makes and therefore
>>>it is playing handicapped in this tournament.
>>>
>>>Enrique
>>
>>I think that crafty cannot use tablebases and this is another reason that it is
>>handicapped.
>>
>>Uri
>I  am sure that crafty could not use tablebases in the way it knows (otherwise
>it would not go for a lost KRP vs KR and understand only after trading rooks
>that it is losing)
>
>Another question:
>Did you tell crafty that it is playing a computer opponent.
>
>In the following position against hiarcs7(game 180)
>crafty's evaluation was 0.33
>4rk2/5R1R/1P6/P1p5/3r3P/8/6PK/3q4 b - - 0 1
>
>I found it strange because it is an obvious draw.
>
>I tried crafty15.18 as an engine for fritz5 and if I tell it computer opponent
>the evaluation becomes 0.
>
>If I give it human opponent in the engine parameters then the evaluation in the
>game is 0.33 advantage for white.
>and if I give it as a position without a game the evaluation againsta human
>opponent is 0.66
>
>Uri

Good eyes.  I've mentioned this before, that Crafty has a "dynamic draw score"
that varies from -1.00 to 0.00 depending on the phase of the game.  This is to
discourage going for a draw in an opening where it gambited a pawn, or in a
middlegame that is pretty even, because it has good tactical skills that might
win.

A draw score of .33 (for white) must mean crafty was black and it saw a
draw...  which is not good against computers, because it means that Crafty
will totally wreck its position to avoid a draw against a very strong opponent.

I have some patches I did for xboard (and sent them to Tim Mann) which recognize
computer opponents on the chess server and send the command "computer" to
crafty.  This forces it to use the normal draw score which should be 0.00 for
most cases, unless the computer is higher rated, where it uses +.2 since a draw
is a good result.

Hopefully this isn't happening in this tournament, however, and maybe I am going
to make this draw score stuff disabled by default and only turn it on when
running on the chess servers against humans...   look for that in 16.4.  :)




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