Author: Dieter Buerssner
Date: 10:22:20 11/30/03
Go up one level in this thread
On November 30, 2003 at 12:49:21, Robert Hyatt wrote:
>On November 30, 2003 at 11:43:45, Bob Durrett wrote:
>>How do the open-source engines, like Crafty, deal with this issue?
>
>_correctly_.
>
>:)
Are you sure?
Crafty 17.14 with the critical position set up:
Black(37): go
time surplus 1:12 time limit 31.29 (3:07)
nss depth time score variation (1)
14-> 0.17 0.00 37. ... Kh7
15 0.17 0.00 37. ... Kh7
15-> 0.41 0.00 37. ... Kh7
16 0.41 0.00 37. ... Kh7
16-> 0.74 0.00 37. ... Kh7
17 0.74 0.00 37. ... Kh7
17-> 1.39 0.00 37. ... Kh7
18 1.39 0.00 37. ... Kh7
18-> 2.75 0.00 37. ... Kh7
19 2.75 0.00 37. ... Kh7
19-> 5.68 0.00 37. ... Kh7
20 5.68 0.00 37. ... Kh7
20-> 11.87 0.00 37. ... Kh7
21 11.87 0.00 37. ... Kh7
21-> 30.95 0.00 37. ... Kh7
22 30.95 0.00 37. ... Kh7
time=1:02 cpu=99% mat=1 n=67680116 fh=90% nps=1077022
ext-> checks=5044426 recaps=120656 pawns=243230 1rep=318232 thrt:4
5078
predicted=0 nodes=67680116 evals=13317768
endgame tablebase-> probes done=4154 successful=460
hashing-> trans/ref=33% pawn=99% used=99%
Black(37): Kh7
time used: 1:02
game is a draw by repetition.
Note, we first see the move, and then the info: "game drawn", which can easily
be interpreted as not correct.
Now the same in xboard mode. It may also show a small bug in Crafty. I had set
up the position after white's 33rd move by fen and forced the moves in the
actual game, just before the critical move. Crafty ignored the movenumber of the
FEN, so I set mn to 37.
White(38): undo
ERROR! move is illegal
NOTICE: 55 moves to next time control
So I set back the mn, then:
White(6): mn 6
move number set to 6
White(6): undo
NOTICE: 56 moves to next time control
Black(5): mn 37
move number set to 37
Black(37): xboard
tellics set 1 Crafty v17.14
kibitz Hello from Crafty v17.14!
go
move g8h7
1/2-1/2 {Drawn by 3-fold repetition}
Again, first the move (which would be shown on the GUI board). Then claiming the
result. Arguably also not correct, and even bad timing could come in. Assume,
xboard just sent the move to ICC. Opponent moves immediatly (say before ICC sees
the draw claim, due to some lag) and with his move, he will not allow another
repetition.
There is no good solution in general for WB/XB. For a manually operated game,
perhaps something like
telluser I write Kh7 on my score sheet now, and claim a draw by this. Please
call the TD, stop the clocks, don't do the move on the board ...
would be sufficient.
I think, GCP is quite right, when he says that probably no engine does this
correctly.
Regards,
Dieter
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