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Subject: Re: different handling of FRC by UCI and Winboard

Author: Reinhard Scharnagl

Date: 16:13:06 06/13/04

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On June 13, 2004 at 18:17:29, Sune Fischer wrote:

>On June 13, 2004 at 17:44:17, Reinhard Scharnagl wrote:
>
>>Well I do not know, whether it would help to explain those points here,
>>but it is a fact, that UCI and Winboard handle FRC very different. And its
>>only up to flexible GUIs like Arena today to cover such weaknesses.
>>
>>1) Winboard does not support FEN position strings for all WBx versions,
>>   but both (WB and UCI) have to support extended FRC-FEN to be fully FRC
>>   aware, because there FRC positions exist, not expressable in normal FEN.
>>2) Winboard handles FRC as a variant, which it is not at all. It is a
>>   compatible upper set of chess. Having supported FRC-FEN strings, there
>>   would be no need to distingush between 'normal', 'fischerandom' and
>>   'nocastle'. The engine simply has to signal to the GUI its FRC awareness,
>>   what could be done easyly in UCI. The GUI then is deciding, whether the
>>   involved engines would play FRC and then support a appropriate starting
>>   position as FEN string.

>In winboard's case I think it's okay to handle FRC as a variant feature.
>
>All these features indicate something outside or above the minimum requirement.
>For a chess engine the minimum requirement is knowing the rules of chess, to
>also know the rules of FRC is an additional "feature", in some sence.

a) a none FRC aware engine has no need to care about such things like FRC.
b) a FRC aware engine has no need to distinguish between those 'variants'.

So what?

>The word variant may not be entirely accurate, but I think that's a bit of an
>academic debate.

No, it is not academic, because that (from the view point of a FRC engine)
unnecessary distinction causes different castling encodings (following the
Winboard specifica for 'fischerandom'). This dualism is 'academic' nonsense.

>>3) a FRC aware engine is always playing FRC, there is not need to switch
>>   between any modes.
>>4) in Winboard there is a formal inconsistence concerning the encoding of
>>   castlings. Because of the inherent identification of all possible FEN
>>   positions it makes no sense to demand a different encoding of castlings
>>   in those 'variants' as specified for 'fischerandom'. UCI has a lack of
>>   specification in that case but also no contradiction.
>>
>>A possible solution to that dilemma is descripted at a page of my site, and
>>in slightly different form implemented within the Arena GUI.
>>[http://www.chessbox.de/Compu/fullchess5b_e.html]

>Regarding your page on the UCI implementation, is this officially part of the
>UCI?

There are two components:
a) the options: why should there be a problem. There is no thinkable conflict.
   Arena seems to handle it that way. It does not hurt any UCI laws.
b) the castling encoding: only the very short castlings have to be encoded in
   a different way, for not to be mixed up with null-moves or regular moves of
   the king. Appending 'k' seems to be natural as in promotions. But the engine
   should always accept alternatives as O-O-O. The behaviour should be choosable
   by another option, because that is a GUI problem to translate between diffe-
   rent engines, e.g. between UCI and Winboard.
Both proposals has been brought to the inventor of UCI, but still have not
become part of a standard. I don't know why. I hope it will be also included.
He wrote in a posting, that this would work compatibly. But obviously he had
not seen a need to support FRC by putting this into the UCI definition. May be
he wants to see first a well working such engine with that protocol.

>I'm also wondering what the reason might be for using a combo box instead of a
>check box, as used for "Ponder"?

As I told, there is no need for a FRC engine to deny that ability. Or why?
Therefore a checkable option or one with alternatives is suggesting nonsense.
Indeed the GUI simply has to check the existence of that option, not its nature.

>shine on,
>-S.

Regards, Reinhard.




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