Author: Uri Blass
Date: 12:15:29 09/06/02
Go up one level in this thread
On September 06, 2002 at 12:14:00, Robert Hyatt wrote: >On September 06, 2002 at 10:56:54, Uri Blass wrote: > >>On September 06, 2002 at 07:23:15, Yuriy Lyapko wrote: >> >>>Which chess engine will see that Rb1 is winning in this position? >>> >>>[D] b4bk1/p2p4/p1p1p2p/P1P1Pp1P/3P3p/2N4N/1r3PP1/4R1K1 w - - >>> >>>Best regards, >>>George >> >>Movei0076 can see a small advantage for white with Rb1(p850,32 Mbytes hash) >>in less than 10 minutes. >> >>I imagine that stronger engines can find it faster. >> >>scores at the last iterations(from white point of view): > > >I don't make any claims about being "stronger" or "weaker" than much of >anything, but Rb1 is the _only_ move Crafty considers. > >It isn't going to like white's position, of course, until it sees white >winning material, which suggests that the bishop scoring needs more control >on the lack of mobility in this position. > >> > >The score starts out at -1.0 (good for black) and drops to about -.5 quickly. > >Which is totally wrong. Movei does not consider pair of bishops in it's evaluation. If we look at pawns and pawn structure then the score is about 0.4 pawns for black based on Movei's evaluation(black has one pawn more but movei reduce 0.3 pawns for every case that there are 2 pawns in the same file). Movei evaluates usually bishop as slightly more than knight but in this position it is not the case because the knights have better squares Movei gives white a small positional advantage because of better mobility except the root position when the black rook is more active than the white rook. I guess that this is the reason for the scores that are close to 0.00 score. At big depth movei can see advntage for white that is increasing Here is movei's output for depth 18-21 Depth 18 0.36 for white Depth 19 0.45 for white depth 20 0.47 for white depth 21 0.54 for white debug file(the negative number of nodes is not a problem that is important for me today) 1256200 <first : 18 36 124813 212119124 e1b1 b2b7 b1b7 a8b7 c3d1 f8e7 d1e3 e7g5 e3c4 g5d8 f2f4 d8c7 g1f2 g8f7 f2e3 f7g7 h3f2 g7f7 f2d3 1571140 <first : 18 36 156307 266204733 e1b1 b2b7 b1b7 a8b7 c3d1 f8e7 d1e3 e7g5 e3c4 g5d8 f2f4 d8c7 g1f2 g8f7 f2e3 f7g7 h3f2 g7f7 f2d3 2533710 <first : 19 45 252564 442753446 e1b1 b2b7 b1b7 a8b7 c3d1 f8e7 d1e3 e7g5 e3c4 g5e7 g1f1 g8g7 f1e2 e7d8 e2e3 d8c7 h3f4 g7f7 c4d6 c7d6 c5d6 3011400 <first : 19 45 300333 525531875 e1b1 b2b7 b1b7 a8b7 c3d1 f8e7 d1e3 e7g5 e3c4 g5e7 g1f1 g8g7 f1e2 e7d8 e2e3 d8c7 h3f4 g7f7 c4d6 c7d6 c5d6 6358390 <first : 20 47 635027 1136886800 e1b1 b2b7 b1b7 a8b7 c3d1 f8e7 d1e3 e7g5 e3c4 g8h8 h3g5 h6g5 c4d6 b7a8 d6e8 g5g4 e8f6 h8g7 f6d7 a8b7 g1f1 7462620 <first : 20 47 745455 1330465799 e1b1 b2b7 b1b7 a8b7 c3d1 f8e7 d1e3 e7g5 e3c4 g8h8 h3g5 h6g5 c4d6 b7a8 d6e8 g5g4 e8f6 h8g7 f6d7 a8b7 g1f1 12739360 <first : 21 54 1273124 -2020697262 e1b1 b2b7 b1b7 a8b7 c3d1 f8e7 d1e3 g8f7 g1f1 f7g8 f1e2 g8g7 e3c4 g7f8 e2e3 f8f7 h3f4 f7g7 f4g6 g7f7 g6h4 d7d5 14875250 <first : 21 54 1486718 -1654416289 e1b1 b2b7 b1b7 a8b7 c3d1 f8e7 d1e3 g8f7 g1f1 f7g8 f1e2 g8g7 e3c4 g7f8 e2e3 f8f7 h3f4 f7g7 f4g6 g7f7 g6h4 d7d5 14875250 <first : move e1b1 Uri
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