Author: Robert Hyatt
Date: 19:56:44 12/25/03
Go up one level in this thread
On December 25, 2003 at 20:11:19, Mike S. wrote: >On December 25, 2003 at 04:07:38, Uri Blass wrote: > >>>>>>>>(...) > >> I definetely know Nimzo 2000 (own GUI) doesn't claim such draws when 0.5 >>>would be lost by it so to speak. >> >>How can it lose 1/2 points by it? >>It only can lose it by a bug. >> >>A program with no stupid bugs cannot get into 3 time reptition from a winning >>position and if the original position is a draw then it does not lose 1/2 point >>by it but only lose some chance that the opponent will go wrong. > >Didn't you ever see that an engine which is otherwise totally lost, saves half a >point with a perpetual? That's very common isn't it? I was talking from the >viewpoint of the *other* engine, the one which was winning when there wouldn't >be a perpetual possible. This engine looses 1/2 by it. So it's purely *idiotic* >to claim from this engines viewpoint. The other engine must do it (or - if it's >a human - may as well miss it!). You are forgetting what the two opponents are made of. _both_ are computers. One is _not_ going to overlook a repetition if it is losing, and the opportunity arises. So the other is _never_ going to bet on that happening... If one side allows a 3-fold repetition, it was _only_ because it could find nothing better than a draw in the tree it searched. That means that the opponent is also going to find that draw... > >You understand?? :-)) > >It's ridiculous when the "winning" engine claims the repetition draw the >opponent has forced to *his* advantage! If you (and the others here) don't >understand this, I can only say sorry. The point is that it is _immaterial_ who claims it, as one certainly will do so. And it is impossible to program alpha/beta to behave like that, it only says "draw". Not "I am losing but this is a draw" or "I am winning but I can't avoid a draw." Just "draw". Which is why all this really doesn't apply to computers. Perhaps to humans, but not to computers. > >Nevertheless, a neutral information for the operator should be possible without >being automatically treated as a claim. > >I this really so difficult to understand, folks?? Come on! It is impossible to understand from someone that has actually written this code several times. The search simply does _not_ work like that. > >Basically it's just about adding the words "I claim a draw due..." to a message >string (or leave these words away for an info message when no claim is intended) >and the rules should be improved respectively, distinguishing between that. Does FIDE require the "I claim"? If so, where in the book is it spelled out. If not, why not? I've never seen an engine just pop up an informational message that says "I just found a draw, but don't claim it, I just thought you'd like to know." As far as the engine is concerned it is talking _to_ the opponent. So "3-fold-repetition" is very specific as to what it means. > >Also (@Bob Hyatt), it's not true that the FIDE rule don't distinguish between >(a) 3-fold repetition and (b) *draw by* 3-fold repetition. Read the rules. It's >only a draw when a draw claim is made based on that, by one player. That isn't what I said. What I said is that FIDE does _not_ require me to "claim a draw by repetition" by saying "I claim a draw by 3-fold repetition." I can just say "this is a 3-fold repetition" and it is over. The words "I claim" are not specified in my FIDE rule book. That was my point for this entire discussion. There is no specific method for doing this. And a human can not just pop up in the middle of the game and say "this is a 3-fold repetition." without meaning to claim the draw. It would be considered poor behavior at best... And as far as the program is concerned, you are not the "operator" you are the "opponent". When it tells you something, it is not just being "chatty". :) > >http://www.fide.com/official/handbook.asp?level=EE1 > >"5.2 (...) The game may be drawn if any identical position is about to appear >or has appeared on the chessboard at least three times. (See Article 9.2)" > >**MAY** be drawn, not must be a draw. And 9.2: > >"9.2 The game is drawn, upon a correct claim by the player having the move, >when the same position, for at least the third time (not necessarily by >sequential repetition of moves) is about to appear, if he first writes his move >on his scoresheet and declares to the arbiter his intention to make this move, >or has just appeared, and the player claiming the draw has the move." > >**Upon a correct claim** --> No claim, no draw. Yes, but look at the specifics. The word "claim" is _not_ required. Making the statement _is_ making the claim. That's what a "claim" is, in fact. > >But maybe you will be telling me that the FIDE rules are wrong :-) No, that you are reading more into them than is there. All I need to do is call the TD over, and say "after I make my move of Nc3, this is a 3-fold repetition". He looks at the game score and says "correct, game is a draw." > >And @ Rolf, didn't you read my theoretical example with an engine which has no >repetition rule implemented? Then, it makes a big difference, if the *opponent* >engine which faces a forced repetition and gives just an info, if it's treated >as a draw claim or not. Because if not, there's a chance to continue and still >win, when the other engine doesn't know it has to repeat and cannot claim it. Is >that too difficult to follow? Yes, except exactly which engine doesn't know about repetitions? And don't say Jonny. It _did_ know about repetitions, it just thought 2-fold was just as bad as 3-fold, which technically it is, from a tree-search perspective. > >Regards, >M.Scheidl
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