Author: Klaus Friedel
Date: 02:09:15 05/02/04
Go up one level in this thread
On May 01, 2004 at 22:51:55, Robert Hyatt wrote: >On May 01, 2004 at 01:41:52, Klaus Friedel wrote: > >>On April 30, 2004 at 23:04:24, Andrew Wagner wrote: >> >>>Here's the position: >>> >>>[d] 8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - >>> >>>The move to find here is Rxb2. My question is...what ply does your program find >>>the solution on? To tactically work it out to see that you can force queening >>>requires something like 13 or 14 ply. This is an interesting knowledge vs. >>>search position...can you special-case this somehow to find it sooner? The >>>problem is, as an FM friend of mine pointed out, if the king were just a bit >>>closer, the sac is losing. E.g. In this position: >>> >>>[d] 8/7p/5k2/5p2/p1p2P2/Pr1p1K2/1P1R3P/8 b - - (white pawn missing on e3) >>>...the sac would be losing because the king is close enough to stop the pawns. >>>So my first inclination to somehow make the static eval see that the pawns were >>>worth being down a pawn seems to be bad. Any thoughts? >> >>Snitch finds it at ply 9 >> >>I hava a special eval term "rook vs 2 connected pawns with king far away" >>to help in such positions. >> >>Snitch0.3.57 WB2 35 MB: >> 1 00:00 0,20 b3b2 >> 1 00:00 1,78 b3b2 d2b2 f6g6 >> 1 00:00 1,87 b3a3 >> 2 00:00 1,72 b3a3 e3e4 >> 2 00:00 1,78 b3b2 d2b2 f6g6 >> 3 00:00 1,96 b3b2 d2b2 c4c3 >> 4 00:00 1,66 b3b2 d2b2 c4c3 b2b7 f6g6 >> 5 00:00 1,66 b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7g6 >> 5 00:00 1,78 f6f7 h2h3 b3b2 d2b2 c4c3 >> 6 00:00 0,53 f6f7 e3e4 f7e6 f3e3 b3b7 e4e5 e6d5 >> 6 00:00 1,15 b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7g6 b7h7 g6h7 >> 6 00:00 1,49 c4c3 b2c3 b3c3 e3e4 c3a3 f3e3 >> 7 00:00 1,20 c4c3 b2c3 b3c3 e3e4 c3a3 e4e5 f6e6 f3e3 >> 7 00:00 1,30 f6g6 >> 8 00:01 0,51 f6g6 e3e4 b3b7 d2g2 g6f6 f3e3 f5e4 e3e4 b7e7 e4d4 >> 8 00:01 0,67 b3b5 e3e4 f5e4 f3e4 b5b7 e4d4 b7c7 d4e4 c7e7 e4d5 >> 8 00:01 0,80 b3b6 e3e4 f5e4 f3e4 b6e6 e4f3 h7h6 d2g2 e6e7 h2h4 f6f5 >> 8 00:01 0,82 b3b7 e3e4 f5e4 f3e4 b7e7 e4d4 e7e2 >> 9 00:01 0,95 b3b7 e3e4 f5e4 f3e4 b7e7 e4d4 e7e2 d2d1 e2c2 d1e1 c2e2 >> 9 00:01 1,02 b3b2 >> 9 00:02 1,86 b3b2 d2b2 c4c3 b2b6 f6e7 b6b7 e7d8 b7f7 c3c2 f7f5 c2c1q f5d5 >>d8e7 d5d3 e7e6 >>10 00:02 1,86 b3b2 d2b2 c4c3 b2b6 f6f7 b6b7 f7e6 b7b6 e6e7 >>11 00:02 1,86 b3b2 d2b2 c4c3 b2b6 f6f7 b6b7 >>12 00:04 2,06 b3b2 >>12 00:08 3,00 b3b2 d2b2 c4c3 b2b6 f6e7 b6b7 e7e6 >>13 00:14 3,20 b3b2 >>13 00:19 3,74 b3b2 d2b2 c4c3 b2b6 f6e7 f3f2 c3c2 b6c6 e7d7 f2e1 d7c6 e1d2 >>c6d5 h2h3 d5e4 h3h4 c2c1q d2c1 e4e3 c1b2 e3f4 >> >> >>Regards, >>Klaus Friedel > > >See what happens if you move the white pawn on e3 to g3. I once had a bug that >would _still_ think this sac (Rb2) was winning in that position when it >definitely is not... Evaluation still works as designed. Rb2 is not selected in this case. Position with pawn moved to g3 [d] 8/7p/5k2/5p2/p1p2P2/Pr1p1KP1/1P1R3P/8 w - - 0 1 Snitch0.3.57 WB2 35 MB: 1 00:00 -1,02 h2h4 f6e6 1 00:00 -0,82 g3g4 f5g4 f3g4 f6e6 1 00:00 -0,74 f3e3 f6e6 2 00:00 -0,74 f3e3 f6e6 3 00:00 -0,69 f3e3 f6e6 e3d4 4 00:00 -0,73 f3e3 b3b8 e3d4 b8c8 d2d1 f6e6 5 00:00 -0,73 f3e3 b3b8 e3d4 6 00:00 -0,72 f3e3 b3b8 e3d4 b8c8 d4d5 h7h6 d5d4 f6e6 7 00:00 -0,66 f3e3 b3b7 e3d4 b7c7 d2d1 f6e6 d1e1 e6d6 8 00:00 -0,46 f3e3 8 00:00 -0,47 f3e3 b3b6 9 00:00 -0,35 f3e3 b3b7 e3d4 b7c7 d4c3 f6e6 10 00:00 -0,39 f3e3 b3b7 e3d4 b7c7 d4c3 f6e6 c3b4 e6d5 b4a4 c7b7 11 00:00 -0,42 f3e3 b3b7 e3d4 b7c7 d4c3 f6e6 c3b4 e6d5 b4a4 c7b7 a4a5 d5e4 12 00:01 -0,61 f3e3 13 00:01 -0,62 f3e3 b3b7 e3d4 b7c7 d4c3 f6e6 c3d4 e6e7 14 00:04 -0,54 f3e3 b3b7 e3d4 b7c7 d4c3 f6e6 d2d1 e6d6 h2h3 d6c5 d1e1 c7d7 e1e5 d7d5 e5e7 h7h5 15 00:05 -0,54 f3e3 b3b7 e3d4 b7c7 d4c3 f6e6 d2d1 e6d6 16 00:18 -0,57 f3e3 b3b7 e3d4 b7c7 d4d5 f6e7 d2d1 h7h5 d1e1 e7f6 e1e6 f6f7 e6e1 c7e7 e1d1 e7e4 d5c5 h5h4 Regards, Klaus
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.