Author: Daniel Kang
Date: 09:31:20 11/19/00
Go up one level in this thread
On November 19, 2000 at 02:30:21, Ricardo Gibert wrote: >On November 19, 2000 at 01:34:14, Uri Blass wrote: > >>On November 19, 2000 at 01:15:22, Ricardo Gibert wrote: >> >>>On November 18, 2000 at 22:13:35, Peter Kappler wrote: >>> >>>>On November 18, 2000 at 21:23:54, Ricardo Gibert wrote: >>>> >>>>>On November 18, 2000 at 12:37:20, Amir Ban wrote: >>>>> >>>>>>On November 18, 2000 at 06:03:39, Graham Laight wrote: >>>>>> >>>>>>>On November 17, 2000 at 19:24:23, Amir Ban wrote: >>>>>>> >>>>>>>> >>>>>>>>If your criterion of knowledge is based on accuracy of evaluation then I >>>>>>>>respectfully apply for membership in the exclusive "knowledge based" club (and >>>>>>>>IMO some members don't belong there). >>>>>>>> >>>>>>>>BTW, accuracy of evaluation is the best criterion for being knowledgable that >>>>>>>>I'm aware of. I've posted here in the past that, to start with, we don't have a >>>>>>>>real definition of what good evaluation means. This is the focus of my work with >>>>>>>>Junior for more than a year. >>>>>>> >>>>>>>IMHO, a truly accurate evaluation of a position would yield one of the following >>>>>>>3 ordinal values: >>>>>>> >>>>>>>Win >>>>>>>Draw >>>>>>>Lose >>>>>>> >>>>>>>-g >>>>>>> >>>>>>>>Amir >>>>>> >>>>>>I can easily fake evaluation that gives only those values. I suppose that you >>>>>>mean that the values should be true values. How do you propose to do that ? If I >>>>>>have an eval that gives absolutely correct values 60% of the time (and the rest >>>>>>wrong), do you expect my program to be weak or strong ? If I get 70% right, am I >>>>>>necessarily stronger ? >>>>>> >>>>>>The question is, given two evaluation functions, to decide which is more >>>>>>accurate. >>>>>> >>>>>>This is a good question. Your answer does not seem to lead anywhere. >>>>>> >>>>>>Amir >>>>> >>>>>With 100% correct evaluations of just win, lose or draw, can a program mate in K >>>>>+ R vs K? I think it will just wander around unless mate happens to fall within >>>>>the program search horizon. Yes? >>>> >>>>Yep, it would wander around until it lucked into a mate or until the "threat" of >>>>a draw by the 50-move rule forced it to play a mating line. >>>> >>>>--Peter >>> >>>The 50 move rule may or may not force it to play a mating line. Example: >>> >>>Lets say the program has played 40 moves without pawn move or capture and is >>>able to search only 20 ply. At that point, it may find that a draw due to the >>>move rule is a problem, but may not be able to anything about it, since the >>>position may actually require more than 10 moves (20 ply) to mate. >> >>If the program has accurate evaluation the 50 move rule is not relevant because >>it will never go to a position that is drawn by the 50 move rule because the >>evaluation will not let it to do it because it is going to tell it that it is a >>draw(the same position with different history of the game should be evaluated as >>a win but accurate evaluation should consider also the history of the game). >> >>If the program has accurate evaluation of draw,win,loss one ply search is enough >>to win won positions. >> >>Uri > >It would be a pretty amazing eval that detects 50-move draws in the eval rather >than in the search. I think the normal assumption is that it is detected in the >search. I think that is quite clear that is the operative assumption in this >thread. Right. But we are talking about a *perfect* evaluation function. If the evaluation function can only distinguish between the three ultimate outcomes, search (beyond one ply) becomes completely redundant. I guess it depends on how you see it but I'd expect a perfect eval to be able to tell if a position is drawn or not. Dan.
This page took 0 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.