Author: Uri Blass
Date: 13:27:08 09/06/02
Go up one level in this thread
On September 06, 2002 at 15:50:25, Robert Hyatt wrote: >On September 06, 2002 at 15:15:29, Uri Blass wrote: > >>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) > >Hey!... > >weren't you one of the ones urging me to go to the 64 bit node counter >in crafty, for longer analysis? > >Get that node counter fixed... :) I remember that I said that I prefered Deep Fritz for deep search because of having correct number of nodes. I also know that the history table may be wrong if I search many nodes but I read that history table is not very important when I use hash tables and killers and some even say that it is counter productive. I guess that I will fix the number of nodes in the future but today it is not in the top of my priorities. Uri
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