Author: Mike S.
Date: 08:25:00 01/28/04
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On January 27, 2004 at 14:49:12, Thomas Mayer wrote: >(...) And as far as I know they did test some positions in a one ply >search... (Where the search itself does not play such a big role - mainly the >eval decides about the move choosed in a one ply search...) - and the version of >List they did test showed almost always the same score and move... I had not read that yet, which is new info for me, before posting a reply below where I suggested just that (IOW. that this should have been done first). Now, I've done just this using the oldest versions of Crafty and List I had quickly available. I think the theoretical, or suspected, chance of similarities (or identical output) in such a case is bigger than when newer, further developed engines are used for the comparison. These were cb-native Crafty 17.14 (run in Fritz 8 GUI) and List 4.61 (WB., run in console mode using the depth and test options). I took 10 positional test positions, because I thought the chance of identical moves is generally better then - so that we can compare evals of the same moves - than in "common" non-test positions. The ply depth was set to 1 ply each. I give the EPD of the positions at the end of the posting. Some of these pos. are somewhat doubtful in a common testing sense, but I think that doesn't matter here. Result: From 10 positions, 6 identical moves were chosen and 4 moves were different. From the 6 same moves each, the evaluation ALWAYS was different. From the 6/10 same moves chosen by both, 3...5 are more or less "obvious" moves, IOW. easy moves like defending the only attacked pawn or moving a piece out of the the attack. Take a look at the moves and positions too see how that is meant. I assume many engines would choose these moves in a one ply search although I didn't check that. I think we can see this as exonerating evidence (=Entlastungsmaterial) in addition to similar contributions by others in several places. Detailed results (evals from White's view): Pos.ID Crafty 17.14 List 4.61 -------------------------------- 25 Bd7 0.17 Bd7 -0.07 26 Rcd1 0.58 c5 0.73 27 Rd7 -0.68 Rd7 -0.80 28 Kf6 2.22 Kf6 2.49 29 Bd7 -1.10 Bd7 -0.99 30 Bxc5+ -0.34 Bxc5+ -0.86 31 Bc6 0.59 f4 0.74 32 Bg2 1.09 Re3 1.08 33 Bb7 0.36 f6 1.00 34 c4 1.41 c4 3.52 Regards, M.Scheidl r1b2rk1/1p2qppp/1bn1p3/p3P3/8/PNQ3P1/1P1B1PBP/R4RK1 b - - bm a4; id "Mike's Test 2.2, Nr. 25"; r5k1/p2r1bpp/2p2p2/8/n1P5/P5B1/5PPP/2R1RBK1 w - - bm c5; id "Mike's Test 2.2, Nr. 26"; 3r1bk1/p4ppp/Qp2p3/8/1P1B4/Pq2P1P1/2r2P1P/R3R1K1 b - - bm e5; id "Mike's Test 2.2, Nr. 27"; 7k/4K1n1/8/6P1/8/3B4/8/8 w - - bm Bg6; id "Mike's Test 2.2, Nr. 28"; r3nrk1/ppq2pbp/2n1b1p1/4pP2/2P5/4BNN1/PP4PP/RQ2KB1R b KQ - bm e4; id "Mike's Test 2.2, Nr. 29"; 8/p2Q2p1/1k3qbp/1pn5/2p4P/2P2P2/5BPK/5B2 w - - bm g3; id "Mike's Test 2.2, Nr. 30"; 2r2rk1/1p1bq3/p3p2p/3pPpp1/1P1Q4/P7/2P2PPP/2R1RBK1 b - - bm Bb5; id "Mike's Test 2.2, Nr. 31"; r1n1kb1r/1b3pp1/1qn1p3/p2pP1Bp/Qp1P1N1P/5NPB/PP3P2/2R1R1K1 w kq - bm Nxe6; id "Mike's Test 2.2, Nr. 32"; 1r1r2k1/2b1qp1p/b1p3p1/p1p1p3/2P1P3/1PN1BP2/P1Q3PP/R2R2K1 b - - bm Rd4; id "Mike's Test 2.2, Nr. 33"; r4k2/2p5/P1pp1n1p/2r2qp1/Q7/6BP/2P2PP1/R3R1K1 w - - bm c4; id "Mike's Test 2.2, Nr. 34";
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