Author: Tony Werten
Date: 01:00:46 02/04/05
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On February 03, 2005 at 09:42:29, Thomas Mayer wrote: >Hi Tony, > >>>> I have coded a few others (KBP[and more Ps] vs K with all rook pawns, and >>>> KPPPP... vs K all rook pawns), but don't use it at the moment. > >>> They are part of my KP*K and KB*P* recognizers... this is quite simple and >>> almost cost zero. If all pawns are on a rook file and the most advanced >>> pawn is a draw in the bitbase then the hole position is draw... > >> I wonder. Did you check the cases where it is a draw because the king >> captures the first pawn ? > >> [D] K7/8/PB6/Pk6/8/8/8/8 b > >in that case the recognizer returns a failure because the weaker side can >capture a pawn. OK so you covered that. You don't have to return complete failure. In XiniX I also return AT_MOST_DRAW and AT_LEAST_DRAW flags . With 2 flags in a row you can return 0 very often with out/limited search. The flags do leave a philosophical problem. Suppose I have 2 positions wich normally evaluate to the same positive value. My recognizer says the first 1 is at least a draw, the 2nd isn't recognized. Should they return different scores ? One can say: Fist is a garantied draw, score it higher. One can also say: 2nd isn't recognized, so a bigger change it's not a draw. >So it see's the draw a bit later -> IMO the task of the It shouldn't. It's a win for white :) Tony >recognizer is > >a) to be fast >b) to return only CORRECT results or tendencies > >if the return of the recognizer is totally wrong you have a problem because it >will hide the result in the tree... > >e.g. one position I had troubles with: > >[D] 5k2/4p2p/6P1/3K4/8/4B3/8/8 w - - 0 1 > >The solution is 1. Bh3+ with >1. ... Kg8 2. g7 Kf7 3. g8Q+!! Kxg8 4. Ke6 Kh8 5. Kf7 e6 6. Bg7++ > >It was not easy to find rules to return a failure in the KB*KP* recognizer in >all positions... Now it works fine... :) You see that I test this with studies >currently... > >Greets, Thomas > >P.S.: And I have removed lots a bugs yesterday -> I feared that it would work >worser -> but it gets even better and faster... >PPS.: Hm, rethinking your position I think instead of a failure I could at least >return a 0 upperbound for white... cool cool... :) I have some work... :)
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