Author: Fabien Letouzey
Date: 03:40:47 04/16/04
Go up one level in this thread
On April 16, 2004 at 06:17:51, Stefan Meyer-Kahlen wrote:
>Hello Fabien,
>On April 16, 2004 at 05:32:17, Fabien Letouzey wrote:
>>Hello Stefan,
>>I thought I had understood the UCI+ specifications, but a user reported to me
>>that a "bestmove 0000" was sent by Shredder. It is true that a 50-move draw
>>could be claimed in that specific case, but I was not at all expecting to
>>receive a null move as "bestmove".
>Oh, did Shredder really do that? :-)
>This should not happen for a "normal" position. Do you have the position handy?
>I assume that is was a position with no legal move left.
>>Could you make a clarification about that issue (e.g. the interface must never
>>send an "already-draw" position, or 0000 is an acceptable best move???)?
>The proper solution would be not to send games with no move left.
>Stefan
Absolutely, but there was at least one legal move in the position.
However, as I said, at least 100 reversible plies had been played before.
So I thought "Shredder knows a draw should have been claimed, therefore it
refuses to search". I just did not like receiving an illegal move as "bestmove"
:)
I have only partial information, but it appears that the user started with a
made up position (KBNK, without tablebases). So "position fen ... moves ..."
was used, maybe the behaviour can never happen with a guenuine game
("startpos").
Here is an extract of my log file; '>' means sent to the engine and '<' received
from it. Unfortunately the user cut the line and inserted "..." instead, but I
know there were at least 100 plies. I have just asked him for a complete log
file by email, but I expect him not to have it anymore.
---
> ENGINE position fen 8/8/8/8/8/4k3/8/B3K2N w - - 0 1 moves h1f2 e3f4 ...
> ENGINE go wtime 24960 btime 55850
< ENGINE bestmove 0000
---
Don't worry about that specific instance (sorry I did not know a made-up
position was used, I thought it was a normal game). All I need to know is that
"bestmove" should not be followed by "0000" in normal circonstances, right?
Thanks!
Fabien.
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