Author: Bob Durrett
Date: 16:36:05 12/09/03
Go up one level in this thread
On December 09, 2003 at 13:21:35, Robert Hyatt wrote: >On December 09, 2003 at 13:02:56, Bob Durrett wrote: > >>On December 09, 2003 at 11:13:56, martin fierz wrote: >> >>>On December 09, 2003 at 10:50:23, Sune Fischer wrote: >>> >>>[snip] >>> >>>>If the bare engine had been playing he would have had to add a few things the >>>>GUI normally takes care of. >>>>For UCI engines it is expected that the GUI handles certain (trivial) things. >>> >>>claiming a draw on 3-fold repetition is *not* a trivial thing. there are >>>different possible cases: >>> >>>1) if your opponent avoids it, he loses >>>2) if your opponent avoids it, he wins >>> >>>in case 2) you should of course claim the draw, because perhaps he will notice >>>he could avoid it. in case 1) however, you can safely repeat the moves, and not >>>claim the draw. it is *not* mandatory to claim a draw on the 3rd repetition. so >>>you should basically not claim it if you might win if your opponent avoids the >>>draw. >>> >>>how do you expect a GUI to make the right decision? imagine the following >>>absurdity: jonny is running without GUI and happily repeats moves against >>>shredder, and does not claim the draw because the engine doesn't know about it. >>>shredder has a bug and allows a 3-fold repetition but will deviate before the >>>fourth repetition. now shredders GUI stops shredder from moving, and says "i >>>claim a draw with my move XY because of 3fold repetition" - this would have been >>>hilarious for everybody except SMK :-) >>> >>>since 3fold repetition is something you claim or don't claim based on the >>>current position, it is clearly something the GUI shouldn't be doing! >>> >>>cheers >>> martin >> >>THIS suggests the obvious changes which should be made to engines and GUIs ASAP >>by all chess programmers. >> >>Before an engine &/or GUI claims a draw, it should evaluate the position and >>determine whether or not it has a strong advantage. > >The engine already _does_ this. It searches every root move individually >and chooses the one that produces the best score. If you get a draw >score back, you can safely assume that no other move will give you a >"strong advantage" since the score of 0.00 was better than any other move. > >QED. It chose the drawing move, thinking a draw was the best outcome >possible in this particular position. > > >> If it does have a strong >>advantage, then claiming a draw would be precluded by the programmer. In other >>words, the software would be programmed in advance to make the sensible choice. > >Which it already does, as I explained. > > >> >>Similarly, the engine/GUI should be programmed to claim a draw by repetition in >>cases where repetition can be played and when also the engine evaluates the >>position as being a strong disadvantage. >> > >The engine will evaluate the position as 0.00 in the above case. > > > >>Obviously, humans avoid claiming repetition draws whenever they are winning and >>claim repetition draws whenever they can if they are losing otherwise. In >>positions perceived to be equal, humans may or may not claim the draw by >>repetition depending on other factors such as tournament standing. > >If you play a move that repeats for the third time. You can claim the >draw. Or your opponent can claim the draw immediately when it is his >move. Playing a repetition for the 3rd time and wishing your opponent >would not notice reminds me of "Grumpy old men". "You can wish in one >hand and crap in the other, and see which one fills up first." > >:) > >> >>Chess computers should be programmed similarly. >> >>Bob D. Bob Hyatt: I don't mean to be unkind, but perhaps you should read my bulletin again. Bob D.
This page took 0.01 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.