Author: Uri Blass
Date: 10:30:13 09/12/01
Go up one level in this thread
On September 12, 2001 at 10:06:01, Robert Hyatt wrote: >On September 12, 2001 at 05:04:55, Uri Blass wrote: > >>On September 12, 2001 at 00:49:38, Robert Hyatt wrote: >> >>>On September 12, 2001 at 00:00:21, Uri Blass wrote: >>> >>>> >>>>1)The size of the tree is not enormous. >>>>If it was so big humans had no chance to prove the draw or equal material by a >>>>tree. >>> >>>First, the size of the tree _is_ enormous. It took many humans, searching >>>all night long, to find the draw in game 2. >> >>No >>It took me with the help of Genius3(p100) and no help from >>other humans few hours to see a draw evaluation >>(I proved at that time by a tree >>that black can force draw evaluation when I consider numbers like >>+0.2 also as a draw) > > > >OK.. Before we proceed, we need to come to a standard definition of "draw". >That is (to a computer) an evaluation of "draw_score" which is typically 0.00. >If you start making wild assumptions, such as "any score < .3 is a draw" then >none of this analysis matters. Because to a computer, .2 is _not_ a draw at >all, and considering it such is an invalid condition to test under. > > > > >> >>I needed some hours because the hardware was slow at that time and >>today 30 minutes are enough. > >If you didn't know the position was a draw from the beginning, I don't >believe you would prove that it is, within 30 minutes. If you could, you >are better than a _bunch_ of GM/IM + computer operators on ICC and FICS. > > > > > > > >> >>I did not publish my analysis at that time but I know that there was >>no need for many humans+many hours to >> >> >>Crafty also can see the draw if you continue >>some plies down in the tree. > >So what? You have to see it from the _beginning_ to prove it is really a >draw. Not based on some human analysis that is hardly perfect in what is >searched and what is excluded. > > > > > >> >> >>The hardest line for computers after Ra6 Qe3 is the following line: >>I used * for obvious singular moves >> >>45.Qxd6 Re8* 46.h4 h5 47.Bf3* Qc1+* 48.Kf2* Qd2+* 49.Be2* Qf4+* >>50.Kg1* Qe3+ 51.Kh2* Qf4+* 52.Kh3* Qxf5+* 53.Kh2* Qf4+* >> >>Here even Crafty can see 0.00 at depth 12 > > > > >Again, you miss the point here. Crafty doesn't necessarily _prove_ that >this position is a draw. It proves that its evaluation suggests that one >side has an advantage, and the other side will therefore try to repeat. It >is not a "proof" that this is a draw, in the same way that a mate score >definitely proves that the position is a mate. Because for mates there are >no positional decisions like "OK, he has a pawn on a3 that I don't think I >can stop so I am going to perp him rather than letting it promote". A few plies >deeper might show that "hey, I can let the pawn promote because I can mate him >anyway..." Deeper search also shows 0.00 score. > >So 0.00 scores do not _prove_ that a position is a draw. It only proves that >one side of the tree search believes it should repeat to avoid something that >looks worse, but which might not be worse at all on deeper analysis. I have >seen _many_ cases in a game where Crafty would say 0.00, and then drop >negative or jump positive on a deeper search. > > > >> >>New position >>[D]4r3/5kp1/R2Q1p2/1p1Pp2p/1Pp2q1P/2P5/4B1PK/8 w - - 0 1 >> >>Analysis by Crafty 18.10: >> >>54.g3 >> +- (2.97) Depth: 1/3 00:00:00 >>54.g3 Qf2+ 55.Kh3 Qxe2 >> -+ (-1.68) Depth: 2/3 00:00:00 >>54.Kh3 >> µ (-1.28) Depth: 2/3 00:00:00 >>54.Kh3 Qe3+ 55.Bf3 Qxc3 >> +- (1.62) Depth: 2/3 00:00:00 >>54.Kg1 Qxh4 >> +- (1.79) Depth: 2/3 00:00:00 >>54.Kg1 Qe3+ 55.Kf1 Qf4+ 56.Ke1 Qxh4+ >> +- (2.14) Depth: 3/6 00:00:00 >>54.Kg1 Qe3+ 55.Kf1 Qc1+ 56.Kf2 Qf4+ 57.Bf3 Qxh4+ >> +- (2.21) Depth: 4/8 00:00:00 >>54.Kg1 Qe3+ 55.Kf1 Qc1+ 56.Kf2 Qf4+ 57.Bf3 Qxh4+ 58.Ke3 >> +- (2.51) Depth: 5/11 00:00:00 >>54.Kg1 Qe3+ 55.Kf1 Qc1+ 56.Kf2 Qf4+ 57.Bf3 Qxh4+ 58.g3 Qg5 >> +- (2.24) Depth: 6/15 00:00:00 21kN >>54.Kg1 Qe3+ 55.Kf1 Qc1+ 56.Kf2 Qf4+ 57.Bf3 Qxh4+ 58.Ke2 e4 59.Qd7+ Re7 >> +- (2.29) Depth: 7/16 00:00:00 55kN >>54.Kg1 Qe3+ 55.Kf1 Qf4+ 56.Ke1 Qc1+ 57.Bd1 Qxc3+ 58.Kf1 Qd3+ 59.Be2 Qf5+ 60.Ke1 >>e4 >> ± (0.78) Depth: 8/17 00:00:01 185kN >>54.Kg1 Qe3+ 55.Kf1 Qf4+ 56.Ke1 Qc1+ 57.Bd1 Qxc3+ 58.Kf1 Qc1 59.Ke2 Qb2+ 60.Kf1 >>Qc1 >> ± (1.16) Depth: 9/23 00:00:01 350kN >>54.Kg1 Qe3+ 55.Kf1 Qf4+ 56.Ke1 Qc1+ 57.Bd1 Qxc3+ 58.Kf1 Qc1 59.Ra7+ Kg6 60.Ke2 >>Qb2+ 61.Kf3 c3 >> ± (1.17) Depth: 10/23 00:00:02 660kN >>54.Kg1 Qe3+ 55.Kf1 Qf4+ 56.Ke1 Qc1+ 57.Bd1 Qe3+ 58.Kf1 Qf4+ 59.Kg1 Qc1 60.Ra7+ >>Kg6 61.Qd7 Qxd1+ 62.Kh2 Rb8 63.Qxg7+ >> ² (0.35) Depth: 11/25 00:00:03 1633kN >>54.Kg1 Qe3+ 55.Kf1 Qf4+ 56.Ke1 Qc1+ 57.Bd1 Qxc3+ 58.Ke2 Qd3+ 59.Ke1 Qc3+ >> = (0.00) Depth: 12/29 00:00:09 4227kN >>54.Kg1 Qe3+ 55.Kf1 Qf4+ 56.Ke1 Qc1+ 57.Bd1 Qxc3+ 58.Ke2 Qd3+ 59.Ke1 Qc3+ >> = (0.00) Depth: 13/34 00:00:29 13389kN >>54.Kg1 Qe3+ 55.Kf1 Qf4+ 56.Ke1 Qc1+ 57.Bd1 Qxc3+ 58.Ke2 Qd3+ 59.Ke1 Qc3+ >> = (0.00) Depth: 14/35 00:00:39 18185kN >>54.Kg1 Qe3+ 55.Kf1 Qf4+ 56.Ke1 Qc1+ 57.Bd1 Qxc3+ 58.Ke2 Qd3+ 59.Ke1 Qc3+ >> = (0.00) Depth: 15/38 00:01:04 29538kN >> >>(Blass, Tel-aviv 12.09.2001) >> >> >>The number of non singular moves in that line is at most 6 plies from >>Deeper blue's point of view(I count also the first 2 plies Ra6 Qe3 >>as non singular(Deeper blue did not expect Qe3 when it played Ra6 so >>it is clear that Qe3 was not singular from it's point of view and >>I assume that Ra6 was also not singular. >> >>Here is part of Deep blue logfile from that position >> >>12(6) #[Ra6](162)[TIMEOUT] 162 T=192 >>ra8a6 Qb6c6q pd5c6Q Rb8c8 be4d5 Kf7e7 ra6a5 Bd6c7 ra5b5P Ke7d6 bd5f3 Kd6e7 rb5c5 >>Rc8a8 bf3d5 Ke7d6 >>--------------------------------------- >>--> 45. Ra6 <-- 15/75:45 >> >>You can see that deeper blue could search depth 18 so >>6 non singular moves mean that the remaining depth from the position >>that Crafty see 0.00 is 12 and depth 12 +singular extension is >>clearly bigger than depth 12 of Crafty. >> >>It seems to me that something is wrong in your assumptions about >>deeper blue(maybe depth 12(6) is not depth 18 and maybe >>deeper blue did not extend a full ply for every singular move. >> > >It didn't extend a full ply for _every_ singular move. I gave the one >constraint that they used, namely that two consecutive plies were limited to >2 plies of extensions, max. It does not change the fact that when all the moves except 6 are singular the reduced depth is not more than 6 plies. I do not care if they extend 1 ply for every singular move or 2 plies for one of them and 0 plies for consecutive move. But your analysis of a forced draw, based on a >0.00 score by a computer, is flawed. Try other programs in the same position >and see if _all_ of them say 0.00... I checked both shredder and Junior and they say 0.00 after a short time Uri
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