Author: Dave Gomboc
Date: 14:55:20 09/06/02
Go up one level in this thread
On September 06, 2002 at 16:27:08, Uri Blass wrote: >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 But since it should take you about three seconds to fix, why don't you go ahead and fix it? Dave
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