Re: A Crime by a Board of Old Imposters

Robert Hyatt wrote:

> > I would be interested to know what the setup was used during the game, 
> > for the Johnny program. Did it use an integrated engine/GUI, did it use 
> > an xboard compatible interface, UCI...
>
>
> I can answer those, other than what was discussed at the time of
> the problem..  Johnny apparently used the chessbase (fritz) GUI as
> the front end...

Ok, that would imply UCI I think, and the GUI signalling the threefold 
repitition. A bit of a mess, I think.

> > > That's different from displaying random junk in an analysis window.
>
> > For me, it depends on what process initiated the popup. If it's the 
> > engine, ok. If it's a separate GUI, maintaining game state and 
> > concluding on its own that a threefold repetition has taken place, I 
> > don't think that should constitute a claim.
>
> What is the basis for separating the GUI from the engine?

To be a bit blunt: sound software engineering practice. The engine and 
the GUI perform different functions; functional decomposition mandates 
that you separate them with a clearly defined interface, in order to 
reduce the total complexity of the system.

> IE crafty has two distinct parts, the input/output, and the
> computation part.

Fair enough. Of course, the engine must be able to get input and output. 
It's only natural to separate this in two parts. I'd say this supports 
my view more than that it contradicts it.

> If I were doing a software engineering project, putting the draw
> claim stuff in the front-end makes perfect sense. 

I disagree. The possibility of a draw claim is something that the 
engine's evaluator should be aware of. If the current player can claim: 
fine: the evaluation for the current player is at least a draw. If 
nothing better comes along, take it. If the opponent can claim: fine: 
the evaluation for the current player in that branch of the search tree 
is at most a draw. The opponent could refuse to claim if he has a better 
option. It's all basic minimax. A possibility to claim a draw is very 
similar to a legal move; it's not obligatory, it has a certain 
evaluation. I'd say all this is best considered and handled by the 
search algorithm, the heart of the engine. If it finds that claiming the 
draw is the best "move", it will do so.

All this leaves of course the interesting possibility that two chess 
programs will get in an infinite exchange of pointless moves, both 
refusing to claim the draw, if they can still force the draw later on, 
but there's also still a deadly mistake that could be made by the opponent.

> It is, after all the part that communicates with the external world.
> Making the engine tell the front end, and the front end tell the world
> seems a bit complicated, not to mention violating a couple of design
> principles for large software projects.

I passionately disagree. The claiming or not claiming a draw is a 
tactical decision, that naturally belongs with the engine, in my 
opinion. It is good software engineering practice to implement 
functionality in the right place, not in a place that is (in most 
circumstances) able to evoke similar behavior by accident.

> > For me, the words "prompted by the engine" have a very specific and 
> > crucial meaning.

> Not for me.  The computer sits on the table and plays chess.  It doesn't
> matter what communicates with the operator.  It only matters that it
> happens...  There has _never_ been a "GUI" component discussion in any
> ICGA event.  There never should be, IMHO.  The engine/gui/computer is
> one symbiotic chess player.  Take any part out and the game can't be
> played.  Does it matter whether your left brain or right brain originates
> a repetition claim?  If not, why does it matter whether the GUI or the
> engine did?  

Because, to me, the GUI is the computer equivalent of the wooden board: 
it's a dumb device on which pieces are moved. Like a regular chessboard, 
it couldn't (and shouldn't) care less if a queen was moved from A1 to 
B8, or if there were 7 kings on the board.

I'd be pretty darn annoyed if my regular local chessclub would buy 
electronical boards that kept track of moves, and announced in the 
middle of time trouble, in a monotonous voice: "draw by repetition of 
position. Game over". A board shouldn't do that, and neither should a 
GUI, IMHO.

- Notwithstanding our almost total disagreement on this (perhaps rather 
philosophical) issue, I am grateful that you take the time to explain 
your view; at the very least, this forces me to state my thoughts as 
clearly as I can.

Best regards,

  Sidney