Author: Rémi Coulom
Date: 09:48:16 08/21/99
Go up one level in this thread
On August 21, 1999 at 10:56:13, Robert Hyatt wrote: >On August 21, 1999 at 04:47:36, Rémi Coulom wrote: > >>Hello, >> >>I spent some time trying to write code to evaluate pawn races in TCB, and I have >>a few comments and questions for programmers. >> >>First, I took a look at the source code of Crafty. I was surprised to find that >>the code can fail in many cases and evaluate that a passed pawn can promote when >>it can not. My guess is that the gains can outweight the problems, but I tend to >>believe that "If you have something that can make a chess program play a stupid >>move, it will happen, and it will probably be during the World Championship". I >>made up a few positions that trap Crafty's evaluation. They are all cases when >>it underestimates the opponent's ability to promote first. It can happen : >> 1. If the opponent has a check that wins a tempo > > >I don't follow. I don't do the pawn race if the opponent has a piece left >(pawns only to trigger the test.) In that case, how can a check win a tempo? The answer is in the following log file. The f passed pawn can win a tempo with f3+. This is why Crafty likes Rxe2+?? for 3 minutes (P90). > >>Crafty v15.17 >> >>Crafty 15.17 vs tcb >>playing a computer! >>pondering disabled. >>choose from book moves randomly (using weights.) >>choose from 5 best moves. >>hash table memory = 6M bytes. >>noise level set to 1000. >> >>White(1): setboard 8/1p3p/p//7P/P3k/2R1b1K w - - >> >> +---+---+---+---+---+---+---+---+ >> 8 | | | | | | | | | >> +---+---+---+---+---+---+---+---+ >> 7 | | *P| | | | *P| | | >> +---+---+---+---+---+---+---+---+ >> 6 | *P| | | | | | | | >> +---+---+---+---+---+---+---+---+ >> 5 | | | | | | | | | >> +---+---+---+---+---+---+---+---+ >> 4 | | | | | | | | P | >> +---+---+---+---+---+---+---+---+ >> 3 | P | | | | *K| | | | >> +---+---+---+---+---+---+---+---+ >> 2 | | | R | | *B| | K | | >> +---+---+---+---+---+---+---+---+ >> 1 | | | | | | | | | >> +---+---+---+---+---+---+---+---+ >> a b c d e f g h >> >>White(1): bd >>Illegal move: bd >>White(1): display >>White(1): analyze >>end-game phase >> clearing hash tables >> time surplus 0.00 time limit 30.00 (3:00) >> depth time score variation (1) >> 5 0.10 5.28 1. Rxe2+ Kxe2 2. h5 f5 3. h6 f4 4. >> a4 >> 5-> 0.27 5.28 1. Rxe2+ Kxe2 2. h5 f5 3. h6 f4 4. >> a4 >> 6 0.45 4.96 1. Rxe2+ Kxe2 2. h5 f5 3. Kg3 Ke3 4. >> a4 >> 6-> 0.67 4.96 1. Rxe2+ Kxe2 2. h5 f5 3. Kg3 Ke3 4. >> a4 >> 7 1.06 4.59 1. Rxe2+ Kxe2 2. h5 f5 3. Kg3 Ke3 4. >> a4 f4+ 5. Kg4 >> 7-> 1.51 4.59 1. Rxe2+ Kxe2 2. h5 f5 3. Kg3 Ke3 4. >> a4 f4+ 5. Kg4 >> 8 2.20 4.56 1. Rxe2+ Kxe2 2. h5 f5 3. Kg3 Ke3 4. >> Kh4 f4 5. Kg4 >> 8-> 3.91 4.56 1. Rxe2+ Kxe2 2. h5 f5 3. Kg3 Ke3 4. >> Kh4 f4 5. Kg4 >> 9 5.23 4.63 1. Rxe2+ Kxe2 2. h5 f5 3. Kg3 Ke3 4. >> h6 f4+ 5. Kg2 Ke2 6. Kh3 Ke3 >> 9-> 7.88 4.63 1. Rxe2+ Kxe2 2. h5 f5 3. Kg3 Ke3 4. >> h6 f4+ 5. Kg2 Ke2 6. Kh3 Ke3 >> 10 8.93 -- 1. Rxe2+ >> 10 11.93 3.57 1. Rxe2+ Kxe2 2. Kh3 f5 3. Kg3 Ke3 >> 4. h5 f4+ 5. Kg2 b5 6. h6 f3+ 7. Kf1 >> a5 >> 10-> 1:23 3.57 1. Rxe2+ Kxe2 2. Kh3 f5 3. Kg3 Ke3 >> 4. h5 f4+ 5. Kg2 b5 6. h6 f3+ 7. Kf1 >> a5 >> 11 1:25 -- 1. Rxe2+ >> 11 1:36 1.86 1. Rxe2+ Kxe2 2. Kg3 Ke3 3. Kg4 Ke4 >> 4. h5 f5+ 5. Kh4 Ke5 6. Kg5 Ke6 7. >> h6 Kf7 8. Kxf5 >> 11 3:04 ++ 1. Rc5!! >> 11 5:14 2.73 1. Rc5 Bf3+ 2. Kh2 Kf4 3. h5 b5 4. >> h6 Be4 5. Rc7 Kg5 6. Rxf7 Kxh6 7. Rf6+ >> Kg5 8. Rxa6 >> 11 5:55 ++ 1. Rc7!! >> 11 6:24 3.50 1. Rc7 Bh5 2. Kg3 b5 3. Rc6 f5 4. Re6+ >> Kd4 5. Rxa6 Ke5 6. Rb6 f4+ 7. Kf2 Be8 >> 11 7:18 ++ 1. Kg3!! >> 11 7:35 3.91 1. Kg3 Bh5 2. Rc5 Bg6 3. h5 Bb1 4. >> Rc7 f5 5. Re7+ Kd4 6. Rxb7 Be4 7. Re7 >> 11-> 8:00 3.91 1. Kg3 Bh5 2. Rc5 Bg6 3. h5 Bb1 4. >> Rc7 f5 5. Re7+ Kd4 6. Rxb7 Be4 7. Re7 >> >>
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