Author: Uri Blass
Date: 01:49:35 03/07/06
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On March 07, 2006 at 03:27:45, Richard Pijl wrote: >On March 06, 2006 at 22:49:11, Dann Corbit wrote: > >>Unstoppable passed pawn. What does your program see as far as pawn score here? >>[D] 8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - bm Rxb2 > >You'll need to know that two connected passers beat a rook when progressed to >3rd rank (or one to 4 and 2) and the defending king is too far away. >You will not find it in reasonable time without this 'knowledge' in your passed >pawn evaluation if you are doing any kind of pruning (including nullmove >pruning) This is not correct Movei find it in a few seconds without that knowledge and it certainly has pruning including null move pruning. Here is the analysis at depth 12 12 106 265 1659869 b3b8 h2h4 h7h5 d2g2 b8b3 g2f2 b3b7 f2d2 f6e6 d2g2 e6d5 12 107 314 1976669 b3b7 12 111 360 2286743 b3b7 h2h4 h7h5 d2g2 b7b8 g2f2 b8g8 e3e4 f5e4 f3e4 g8e8 e4f3 f6f5 f2g2 12 112 429 2811982 b3b2 12 141 454 3042096 b3b2 12 240 543 3690983 b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7h6 b7b6 h6h5 b6b5 c3c2 b5f5 h5h4 f5f6 h7h5 f6c6 d3d2 c6c2 d2d1q c2e2 12 240 554 3778228 b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7h6 b7b6 h6h5 b6b5 c3c2 b5f5 h5h4 f5f6 h7h5 f6c6 d3d2 c6c2 d2d1q c2e2 >It took me a little while to get this correct in the Baron, but now it solves it >at a 3 ply search in 0.02 seconds on a Xeon 2.8 Ghz: > > ply time nodes score pv > 2( 2)& 0:00.02 115 +0.78 Kf6-e6 e3-e4 > 2( 2)& 0:00.02 174 +0.90 Rb3-b5 Rd2-g2 > 2( 2)& 0:00.02 223 +0.93 Rb3-b6 e3-e4 (f5xe4) > 2( 2)& 0:00.02 272 +1.01 Rb3-b7 e3-e4 (f5xe4) > 2( 2)& 0:00.02 321 +1.04 Rb3-b8 e3-e4 (f5xe4) > 2( 2). 0:00.02 393 +1.04 Rb3-b8 e3-e4 (f5xe4) > 3( 6)& 0:00.02 557 +1.20 Rb3-b8 e3-e4 f5xe4 Kf3xe4 Rb8-d8 > 3( 6)+ 0:00.02 898 +1.99 Rb3xb2 (Rd2xb2) (c4-c3) > 3( 6)& 0:00.02 967 +3.16 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7 > 3( 6). 0:00.02 989 +3.16 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7 This knowledge is not correct and based on this knowledge it may find Rxb2 also in the following diagram with the same PV. [D]8/7p/5k2/5p2/p1p2P2/Pr1p1K2/1P1R3P/8 b - - Uri
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