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Subject: Re: Computers-underpromotion

Author: Robert Hyatt

Date: 09:53:01 04/16/00

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On April 16, 2000 at 11:06:16, blass uri wrote:

>On April 16, 2000 at 09:53:15, Robert Hyatt wrote:
>
>>On April 16, 2000 at 09:25:33, Daniel Clausen wrote:
>>
>>>Hi
>>>
>>>On April 16, 2000 at 09:11:08, Charlie GOLD wrote:
>>>>     Crafty analysed the position and showed # in one (Pf8-N #), BUT IT DID NOT
>>>>MAKE THE MOVE UNTIL I FORCED IT TO. The other machines made the move in less
>>>>than 5 seconds.   charlie
>>>
>>>Some engine continue with the search when they found a mate-in-N on a
>>>certain ply in the hope to find a shorter mate. Of course in the case
>>>of a mate-in-1 this is a bit silly. :) Maybe you saw this effect in
>>>Crafty?
>>>
>>>Kind regards,
>>> -sargon
>>
>>
>>Crafty stops at the right point, _unless_ given a sd=N command.  It uses the
>>rule of "search to 2*N=1" when it finds a mate in N, just to be sure there
>>isn't a shorter mate.    In the position you gave, it stopped after 4 plies
>>as that is the minimum depth it will normally search to, regardless of the
>>mate found...
>>
>>I don't see how it could continue to search unless it is in infinite mode or
>>a specific depth has been given to it...
>
>I know that under chessbase crafty always use time to play even when it can see
>mate in 1 and the only cases that it does not use time are because of the
>permanent brain.
>
>It does not change the result of the game but I saw crafty using 246 seconds to
>do mate in 1 against Fritz6 in the ssdf games when it was under chessbase
>interface.
>It has nothing to do with underpromotions.
>
>Under infinite time control it will never play because it "believes" that it has
>to use time.
>
>Uri


That is interesting. I have no idea how the GUI could make it take a long time,
unless it is setting the time limit wrong.  IE Crafty has a st=N command that
says use N seconds of time.  But that is the wrong way to play games as it will
always take N seconds, never any less (on easy moves), never any more (when the
score drops drastically).

Can you (or someone) send me a log file from where this happens?  I'd like to
find out why it is doing something it won't do under winboard or in text mode.

Bob



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