Author: Robert Hyatt
Date: 08:56:20 05/21/01
Go up one level in this thread
On May 21, 2001 at 11:48:09, Bruce Moreland wrote: >On May 21, 2001 at 10:18:16, Robert Hyatt wrote: > >>On May 21, 2001 at 06:52:52, Uri Blass wrote: >> >>>This position could happen in kasparov-Deeper blue but kasparov did not play >>>40.gxh5 >>> >>>Based on Deeper blue logfiles we know that Deeper blue evaluated the position >>>as 0.5 pawn advantage for white at depth 9(6)=15 >>> >>>Crafty's evaluation at depth 15 is 2.93 pawns for white so we can see that the >>>difference in evaluation is 2.43 pawns. >>> >>>Part of the difference can be explained by different evaluation but most of the >>>difference is clearly because of the fact that Crafty can see more than Deeper >>>blue. >> >>You should be able to see crafty's PV, which would clearly explain whether >>the 2.9 is position or material. Unfortunately, you can not see DB's PV >>so there +.5 is totally unknown. IE it could be just a bit better positionally, >>it could be material down and a really big positional plus. Who knows? and >>who can tell? > >You give a supported pawn on the 7th a big bonus, and that's what white has >here. So I'm betting it's a positional thing. > >bruce Wouldn't surprise me at all. One thing Uri can do to see where the scores are coming from is to set up the position in question, using the FEN input string, then type "reada" and hit return. cut/paste the PV above into the text window and hit enter. Crafty will run down the PV and make each move on the board. Once that is done, type "score" and it will give the various scoring components that go into making up the score. IE material, pawns, passed pawns, you-name-it... That's why I said it is a mistake to compare evaluations of programs. IE I have seen positions where Gambit Tiger said +3 and lost, I have see positions where it said +3 and won. Positional scores are simply "guesses" or "approximations". Taking those scores as "this is the absolute value of this position" is really flipping a coin and hoping for "edge" to come up. > >> >> >> >>> >>>Deeper blue found the line 40...Bxh5 41.Rh1 only at depth 10(6)=16 when Crafty >>>could see it at depth 14 and the line was not changed at the next 2 plies. >> >>This is the same problem. My eval is tuned to more risky play, because of the >>opposition I see on ICC all the time. In some types of positions I would >>expect it to get a much better picture of the real score than DB. But in >>others I would expect it to get a worse idea. And tactically, it would be >>no competition with DB having a huge edge. >> >>If DB searches 16, and crafty searches to 16, I would prefer the non-null-move >>16 any day. It is _clearyly_ more accurate. >> >> >> >> >> >>> >>>Crafty can see the line 40...Bxh5 41.Rh1 Bf3 42.Rg1 Bh5 43.g7 Nf3 44.Rg3 c5 >>>45.bxc5 Rc8 46.f6 Rxc5 at depth 15 and 16 when Deeper blue can see it only at >>>depth 17,18(deeper blue can see a different line but the difference is only >>>41...Kg5 42.Rg1 Kh6 that leads to the same position as 41..Bf3 42.Rg1 Bh5 and >>>moves 43-46 are the same. >>> >>>It seems that Crafty is a very good program and it can outsearch deeper blue by >>>2 plies. >> >> >>That's a speculation that is based on too many what-ifs. IE what if you just >>let each program search for 3 minutes? Which is better? I don't like to >>compare search depth to search depth, as that is usually a totally wrong way >>to compare programs. IE you might try hiarcs at the same depth and find that >>it sees more or less. >> >>Plies between programs are not really interesting. >> >> >> >> >>> >>>I do not know the meaning of the plies of deeper blue but it seems to be not >>>brute force search. >>> >>>I also doubt if deeper blue could search 200M nodes per second otherwise I >>>cannot understand the reason that it is outsearched by other top programs again >>>and again based on the pv's >> >>What "top program" sees more in 3-4 minutes than they do? IE what program >>can solve all the nolot positions in reasonable time (maybe 1-2 exceptions >>as I think they missed one or two). But who can do all but 2 in 3-4 minutes? >>To say "top programs outsearch them" therefore seems strange. Unless you mean >>"top programs outsearch them given _enough_ time". And that is always true and >>meaningless at the same time. >> >> >> >> >>> >>>It is possible that the claims about 200M nodes per second were only a >>>psychological war against kasparov >> >> >>Not a chance... I have sat behind them and watched too many times... >> >> >>> >>>Here is the analysis of Crafty >>> >>>kasparov - Deeper blue >>>[D]3rr3/8/2p3Pk/1p2nP1P/pP2p3/P1B1Nb1B/2P2K2/5R2 b - - 0 1 >>> >>>Analysis by Crafty 18.08: >>> >>>40...Kxh5 >>> +- (1.42) Depth: 1/8 00:00:00 >>>40...Kxh5 41.g7 Ng4+ 42.Bxg4+ Bxg4 >>> +- (1.68) Depth: 2/8 00:00:00 >>>40...Kg7 41.f6+ Kxf6 >>> +- (1.53) Depth: 2/8 00:00:00 >>>40...Kg7 41.f6+ Kxf6 42.Kg3 >>> +- (1.53) Depth: 3/8 00:00:00 >>>40...Kg7 41.Ng4 Bxg4 42.Bxg4 c5 >>> +- (2.58) Depth: 4/10 00:00:00 >>>40...Rd6 >>> +- (2.18) Depth: 4/10 00:00:00 >>>40...Rd6 41.Rg1 Bxh5 42.g7 Bf7 >>> +- (2.03) Depth: 4/10 00:00:00 >>>40...Kxh5 >>> +- (1.63) Depth: 4/10 00:00:00 >>>40...Bxh5 41.Bg2 Bf3 42.Bh3 >>> ± (1.34) Depth: 4/10 00:00:00 >>>40...Bxh5 41.Bg2 Nxg6 42.fxg6 Rf8+ 43.Ke1 Rxf1+ 44.Kxf1 Bxg6 >>> ± (1.33) Depth: 5/16 00:00:00 >>>40...Bxh5 41.Kg3 Kg5 42.Rf4 Bf3 43.Rh4 >>> +- (1.62) Depth: 6/16 00:00:00 88kN >>>40...Bxh5 41.Rg1 Kg7 42.Bg4 Kh6 43.Bxe5 Rxe5 44.Rh1 >>> +- (1.76) Depth: 7/19 00:00:01 222kN >>>40...Bxh5 41.Rg1 Nf3 42.Rh1 Kg5 43.g7 Rg8 44.f6 Kf4 >>> +- (1.81) Depth: 8/20 00:00:01 480kN >>>40...Bxh5 41.Rg1 Nf3 42.Rh1 Ne5 43.Bg2 Nxg6 44.fxg6 Kxg6 >>> +- (1.78) Depth: 9/23 00:00:03 1223kN >>>40...Kxh5 41.Rg1 Kh4 42.Bf1 Kh5 43.g7 Ng4+ 44.Nxg4 Bxg4 45.Rh1+ Kg5 46.f6 e3+ >>>47.Kg3 >>> +- (1.77) Depth: 9/23 00:00:04 1778kN >>>40...Kxh5 41.Rg1 Kh4 42.Bg2 Bxg2 43.Rxg2 Kh5 44.g7 Nf7 45.Rg6 Nd6 46.Bd4 >>> +- (2.01) Depth: 10/26 00:00:07 3318kN >>>40...Bxh5 41.Kg3 Kg5 42.g7 Nf7 43.f6 Rg8 44.Rf4 Bf3 45.Be6 Kg6 >>> +- (1.94) Depth: 10/26 00:00:14 6548kN >>>40...Bxh5 41.Kg3 Kg5 42.g7 Nf7 43.f6 Rg8 44.Be6 Bg6 45.Rh1 Rd6 46.Bg4 >>> +- (2.16) Depth: 11/27 00:00:24 11929kN >>>40...Kxh5 41.Rg1 Kh4 42.Bg2 Bxg2 43.Rxg2 Kh5 44.g7 Nf7 45.Bf6 Rd2+ 46.Kf1 Rxg2 >>>47.Kxg2 >>> +- (2.14) Depth: 11/27 00:00:33 16243kN >>>40...Kxh5 41.Rg1 Kh6 42.g7 Nf7 43.Rg6+ Kh7 44.Rxc6 Rc8 45.Rxc8 Rxc8 46.Bd4 Rd8 >>>47.Bc3 Kg8 >>> +- (2.53) Depth: 12/29 00:01:24 41952kN >>>40...Bxh5 41.Kg3 Kg5 42.g7 Nf3 >>> +- (2.45) Depth: 12/29 00:01:48 54476kN >>>40...Bxh5 41.Kg3 Kg5 42.g7 Nf7 43.Rf4 Nd6 44.f6 Bg6 45.Rg4+ Kh5 46.Kf4 Rg8 >>>47.Rg5+ Kh4 48.Be6 >>> +- (2.71) Depth: 13/32 00:02:59 89583kN >>>40...Bxh5 41.Rh1 Kg5 42.Rg1+ Kf6 43.Bg2 Bf3 44.Bxf3 exf3 45.g7 Kf7 46.g8Q+ Rxg8 >>>47.Rxg8 Rxg8 48.Bxe5 Re8 49.Ng4 >>> +- (2.61) Depth: 14/34 00:08:56 267478kN >>>40...Bxh5 41.Rh1 Bf3 42.Rg1 Bh5 43.g7 Nf3 44.Rg3 c5 45.bxc5 Rc8 46.f6 Rxc5 >>>47.Bb4 Rg5 48.Rxg5 Kxg5 >>> +- (2.93) Depth: 15/39 00:23:36 722662kN >>>40...Bxh5 41.Rh1 Bf3 42.Rg1 Bh5 43.g7 Nf3 44.Rg3 c5 45.bxc5 Rc8 46.f6 Rxc5 >>>47.Bb4 Rg5 48.Rxg5 Kxg5 49.Be7 >>> +- (3.06) Depth: 16/40 00:43:40 1309529kN >>> >>>(Blass, Tel-Aviv 21.05.2001) >> >> >>That shows that Crafty can get to depth=16 after searching a billion nodes. >>With Null-Move (R=3) that equates to a brute-force of 13 plies. I'm not sure >>how to reach any comclusion from that. >> >>There are _always_ positions that Crafty will evaluate better than _anybody_. >>There are always positions where it will evaluate worse. Ditto for tactics. >>Unfortunately, one position doesn't win a game, although one can lose it.
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