Author: Baier Helfried
Date: 00:24:45 02/12/98
Go up one level in this thread
On February 11, 1998 at 08:57:04, Robert Hyatt wrote: >On February 11, 1998 at 02:52:29, Bernhard Bauer wrote: > >>On February 10, 1998 at 12:09:49, Bruce Moreland wrote: >> >>>Cool bug. If you want to see other bugs of this type, try setting up >>>positions where each side has only one minor piece, but there is a mate >>>in one. >>> >>>For instance something like >>> >>>5Bbk/8/7K/8/8/8/8/8 w - - 0 1 >>> >> >>Crafty gives: >> >> White(1): Bg7# >> time used: 0.18 >> >> Crafty offers a draw. >> >>So after mating Crafty offers a draw. >> >>>When I tried this a few years ago I found that several programs called >>>this a draw. Maybe they still do. >>> >> >>Looks like you are right. >> >>>Regarding 5-piece endgame databases, I have a whole bunch of them, but I >>>don't actually use very many on ICC, since the Alpha doesn't have enough >>>disk. >>> >>>One of the ones I put on the Alpha, almost as a lark, was KP vs KNN, and >>>it has come in handy twice, which was twice more than I expected. >>> >> >>I think it's a good idea to do things in a proper way. Crippling down a >>program for speed reasons may be a bad idea and may give the customers >>a bad feeling. It would be better to insert a line of code like: >> > >you are assuming facts not in evidence. The reason *I* do what I did is >to win games that are winnable. IE imagine a position where there are 7 >pieces on the board. White has a king, two knights and a pawn. Black >has >a king knight and bishop. Crafty finds a way to win one of black's >pieces for a pawn, and concludes "hey, I have two pieces vs one piece >for my opponent, >that's +3, so I'm going for it since the current score is only + 1. But >the resulting position ends up a draw. Since it is impossible to >determine >which are winnable and which are drawable by search, I have to either >say >"draw or +3". DRAW is right 99.99999 percent of the time. > >It isn't a speed issue at all. IE imagine intentionally heading into >these >+3 types of position tactically, only to find out 50 moves later there >was >no way to win. It happened many times until I fixed this. I'd rather >win >100 and draw 1, than draw 100 and win 1. > >>XXX will not handle this position properly due to speed reasons. STOP. >> >>Here are 2 positions from V. Albillo's home page that cause difficulties >>to crafty. >> >>8/1k1K4/8/8/1pN5/1N6/8/8 w - - bm Nc5+; id "VA19: 6mate"; >>8/8/8/5K2/7k/7p/7N/7N w - - bm Nf2; id "VA20: 9mate"; >> >>Now I know why. >> >>Regards >>Bernhard >>>bruce as far as I know KQx-k (x is Q,R,...) positions are all 1-0 positions except for a stalemate. Does Crafty use this tablebase files or can I delete it? Regards Helfried
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