Author: Robert Hyatt
Date: 11:13:36 02/19/02
Go up one level in this thread
On February 19, 2002 at 11:26:51, Uri Blass wrote: > >If you look at the position after Kf1 then programs cannot find draw score >mainly because of the fact that they do not know to evaluate other lines as a >draw and Deep Fritz evaluates it as a clear advantage for white but does not >choose deeper blue moves. > >Here is Deep Fritz's analysis one ply after 44.Kf1 Rb8 >After some minutes it changes it's mind and do not choose deeper blue move >45.Ra6 > >You can criticize deep Fritz for not evaluating correctly the endgame when it >gives evaluation of +1.56 for a drawn endgame but the problem that prevent Deep >Fritz to see the draw does not seem to be the 60 ply line. > >Deep Fritz understands enough to choose the correct move at move 44 >1.91 at depth 24 for 44.Kh1 compared to 1.56 at depth 22 for 45.Qd7+ This doesn't mean it understands _anything_ here. It just happens to like one move over the other due to its evaluation. How many programs find a wild sacrifice simply because they misunderstand the resulting position and think it is better for the _wrong_ reasons? > >[D]Rr6/5kp1/1qQb1p1p/1p1PpP2/1Pp1B3/2P4P/6P1/5K2 w - - 0 1 > >Analysis by Deep Fritz: > >45.Qd7+! > ± (1.31) Depth: 3/11 00:00:00 1kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 > ± (1.34) Depth: 5/12 00:00:00 4kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 > ± (1.34) Depth: 5/12 00:00:00 4kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 > ± (1.34) Depth: 5/12 00:00:00 4kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 > ± (1.34) Depth: 5/12 00:00:00 4kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 > ± (1.34) Depth: 5/12 00:00:00 4kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 > ± (1.34) Depth: 5/12 00:00:00 4kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 > ± (1.34) Depth: 5/12 00:00:00 4kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 49.g3 > +- (1.44) Depth: 6/16 00:00:00 9kN >45.Qd7+-- > ± (1.13) Depth: 7/15 00:00:00 22kN >45.Qd7+-- > ± (1.13) Depth: 7/15 00:00:00 25kN >45.Qxb6! > ± (1.16) Depth: 7/15 00:00:00 27kN >45.Qxb6! Rxb6 46.Ra7+ Kf8 47.g3 h5 48.Ke2 h4 49.gxh4 > ± (1.25) Depth: 7/18 00:00:00 38kN >45.Ra6! > ± (1.28) Depth: 7/18 00:00:00 48kN >45.Ra6! Qxc6 46.dxc6 Ke8 47.Ra7 Rc8 > ± (1.38) Depth: 7/18 00:00:00 53kN >45.Ra6 Qxc6 46.dxc6 Ke8 47.Ra7 Rc8 > ± (1.38) Depth: 8/18 00:00:00 80kN >45.Ra6 Qxc6 46.dxc6 Ke8 47.Ra7 Rd8 > +- (1.44) Depth: 9/21 00:00:00 157kN >45.Ra6 Qxc6 46.dxc6 Bc7 47.Ra7 Rc8 48.Rb7 Ke7 49.Ke2 Kd6 50.Rxb5 > +- (1.44) Depth: 10/24 00:00:00 303kN >45.Ra6 Qxc6 46.dxc6 Kg8 47.Ra7 Rc8 48.Rb7 Kf8 49.Rxb5 > +- (1.53) Depth: 11/28 00:00:01 839kN >45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rd8 48.Rb7 Ra8 49.Rd7 Be7 50.c7 Ra1+ > +- (1.59) Depth: 12/30 00:00:02 1617kN >45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 48.Rb7 Bc7 49.Rxb5 Ke7 > +- (1.66) Depth: 13/32 00:00:04 3128kN >45.Ra6 Qxc6 46.dxc6 Rc8 47.Ra5 Ke7 48.Rxb5 h5 49.Bd5 > +- (1.78) Depth: 14/34 00:00:11 7087kN >45.Ra6-- > +- (1.47) Depth: 15/40 00:00:59 37421kN >45.Ra6-- Qe3 46.Qd7+ Kg8 47.Qxd6 Rf8 48.Qe6+ Kh7 49.Qe7 Rg8 50.Bf3 Qc1+ > ± (1.22) Depth: 15/41 00:01:18 49651kN >45.Ra6 Qe3 46.Qd7+ Kg8 47.Qxd6 Rf8 48.Qe6+ Kh7 49.Bf3 Qc1+ 50.Kf2 Qd2+ > ± (1.22) Depth: 16/45 00:02:48 106539kN >45.Ra6 Qe3 46.Qxd6 Re8 47.h4 h5 48.Bf3 Qc1+ 49.Kf2 Qd2+ 50.Be2 Qf4+ > ± (1.00) Depth: 17/43 00:06:12 235347kN >45.Qd7+! > ± (1.03) Depth: 17/43 00:07:40 293411kN >45.Qd7+! Kg8 46.Ra7 Bf8 47.Qe6+ Kh8 48.Qxb6 Rxb6 49.Bf3 Bd6 50.Ra8+ Kh7 > ± (1.31) Depth: 17/44 00:08:23 320283kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh8 48.Qxb6 Rxb6 49.Bf3 Bd6 50.Ra8+ Rb8 > ± (1.28) Depth: 18/42 00:09:56 379789kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Ke2 Kh7 48.Qf7 > +- (1.47) Depth: 19/44 00:17:16 662024kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qf7+ Kh8 48.Ke2 Qd6 49.Qe6 Qb6 50.Qxb6 Rxb6 > +- (1.50) Depth: 20/47 00:33:48 1297637kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qf7+ Kh8 48.Ke2 Qd6 49.Qe6 Qb6 50.Qxb6 Rxb6 > +- (1.53) Depth: 21/48 01:05:55 2543899kN >45.Qd7+ Kg8 46.Ra7 Bf8 47.Qf7+ Kh8 48.Ke2 Qd6 49.Qe6 Qb6 50.Qxb6 Rxb6 > +- (1.56) Depth: 22/52 02:25:04 5625115kN > >[D]R7/1r3kp1/1qQb1p1p/1p1PpP2/1Pp1B3/2P4P/6P1/6K1 w - - 0 1 > >Analysis by Deep Fritz: > >44.Qxb6 Rxb6 45.Ra7+ Kf8 > ± (0.94) Depth: 2/7 00:00:00 >44.Qxb6 Rxb6 45.Ra7+ Kf8 > ± (0.94) Depth: 2/7 00:00:00 >44.Qxb6 Rxb6 45.Ra7+ Kf8 > ± (0.94) Depth: 2/7 00:00:00 >44.Qxb6 Rxb6 45.Ra7+ Kf8 46.Kf2 > ± (1.13) Depth: 3/9 00:00:00 >44.Qxb6 Rxb6 45.Ra7+ Kg8 46.Kf2 Kh7 > ± (1.03) Depth: 4/9 00:00:00 >44.Qxb6 Rxb6 45.Ra7+ Be7 46.Kf2 Rd6 47.g3 > ± (0.84) Depth: 5/11 00:00:00 2kN >44.Kf1! > ± (0.88) Depth: 5/12 00:00:00 3kN >44.Kf1! Qxc6 45.dxc6 Rc7 46.Ra5 Ke7 47.Rxb5 > ± (1.28) Depth: 5/13 00:00:00 5kN >44.Kf1 Qxc6 45.dxc6 Rc7 46.Ra5 Ke7 47.Rxb5 > ± (1.28) Depth: 6/14 00:00:00 7kN >44.Kf1 Rb8 45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 > ± (1.34) Depth: 7/16 00:00:01 17kN >44.Kf1 Rb8 45.Qd7+ Kg8 46.Ra7 Bf8 47.Qe6+ Kh7 48.Qxb6 Rxb6 49.g3 > +- (1.44) Depth: 8/18 00:00:01 37kN >44.Kf1 Rb8 45.Qxb6 Rxb6 46.Ra7+ Kf8 47.g3 h5 48.Ke2 h4 49.gxh4 > ± (1.25) Depth: 9/19 00:00:02 84kN >44.Kf1 Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.g3 Rc8 48.Ra5 Rb8 49.Ra7 Rc8 > ± (1.38) Depth: 10/25 00:00:03 212kN >44.Kf1 Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 > ± (1.38) Depth: 11/25 00:00:03 392kN >44.Kf1 Rb8 45.Ra6 Qxc6 46.dxc6 Bc7 47.Ra7 Rc8 > +- (1.44) Depth: 12/28 00:00:04 859kN >44.Kf1 Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 > +- (1.50) Depth: 13/30 00:00:06 1917kN >44.Kf1 Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 48.Rb7 Ra8 > +- (1.59) Depth: 14/34 00:00:09 4077kN >44.Kf1 Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 48.Rb7 Rc7 49.Rxb5 Ke7 > +- (1.66) Depth: 15/38 00:00:16 8762kN >44.Kf1 Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 48.Rb7 Rc7 49.Rxb5 > +- (1.78) Depth: 16/37 00:00:38 22540kN >44.Kf1 Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 48.Rb7 Rc7 49.Rxb5 Ke7 > +- (1.78) Depth: 17/39 00:01:10 43120kN >44.Kf1-- > +- (1.47) Depth: 18/44 00:03:32 131479kN >44.Kf1-- Rb8 45.Qd7+ Kg8 46.Ra7 Bf8 47.Qf7+ Kh7 48.Ke2 Rd8 49.Qb7 Rb8 > ± (1.31) Depth: 18/45 00:07:15 272559kN >44.Kh1! > ± (1.34) Depth: 18/45 00:09:10 346790kN >44.Kh1! Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 48.g3 Rc7 49.Ra8+ Kf7 > +- (1.50) Depth: 18/45 00:10:39 402006kN >44.Kh1 Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 48.g3 Rc7 49.Ra5 Ke7 > +- (1.63) Depth: 19/46 00:13:29 512685kN >44.Kh1 Rb8 45.Ra6 Qxc6 46.dxc6 Kf8 47.Ra7 Rc8 48.g3 Rc7 49.Ra5 Ke7 > +- (1.63) Depth: 20/48 00:22:01 842954kN >44.Kh1 Rb8 45.Ra6 Qxc6 46.dxc6 Rc8 47.Ra5 Ke8 48.Kh2 Ke7 49.Rxb5 Rb8 > +- (1.78) Depth: 21/50 00:40:58 1579956kN >44.Kh1 Rb8 45.Ra6 Qxc6 46.dxc6 Rc8 47.Ra5 Ke7 48.Rxb5 h5 49.Kh2 h4 > +- (1.81) Depth: 22/51 01:44:09 4053399kN >44.Kh1 Rb8 45.Ra6 Qxc6 46.dxc6 Rc8 47.Ra5 Ke7 48.Rxb5 h5 49.g3 Bc7 > +- (1.88) Depth: 23/53 03:11:14 7470799kN >44.Kh1 Rb8 45.Ra6 Qxc6 46.dxc6 Rc8 47.Ra5 Ke7 48.Rxb5 h5 49.g3 Bc7 > +- (1.91) Depth: 24/53 06:27:16 15175713kN > >(Blass, Tel-aviv 04.09.2001) The question is, can it see that Kf1 is a draw? The answer is obviously "not just no, but heck no..." Not even close. Give it as long as you want. A week or a month or a year... > >No >I did not say that the pruning rules are going to prune all the legal moves >except one. It doesn't matter. _if_ you can create a forward pruning rule that is _always_ right, even though it only eliminates _one_ move, then it is easy to prove that you can _also_ produce a forward pruning move that is always right even when it eliminates more than one move. I claim that such is _impossible_. You might get the error down to .0001% if you are very lucky. But that is not zero, and it will fail. > >The pruning rules should detect illogical moves and reduce the size of the chess >tree. > >They should not resuce it to 0. > >If you prune in every move only 40% of the possible moves you are goinbg to >reduce the size of the chess tree significantly but you are not going to solve >chess. Correct. The error rate will be so huge that it won't prove anything at all about the game. > >I do not think that you need billions of lines and I believe that some millions >may be enough because one rule can be good for many position. Pick an iron-clad position where you can eliminate a move for a specific reason. And let's see if we can break it. Then you fix it. Then we break it. And this goes on almost forever... > >a big part of the work will not be to write the code but to discover the right >pruning rules. >It is possible to write thousands of lines today and correct the errors without >million of dollars. No it isn't. Any good software engineering book will explain the problems and why software is in the shape it is in today. The concept of a "bug-free program" is and always will be an oxymoron, when "program" means something with thousands of lines. > >If you get some millions of dollars for a project then it may be possible to do >better. Do you think windows 2000 has been supported by "millions of dollars"? What about Unix at AT&T? VMS at Digital? IRIX at SGI? VM and AIX at IBM? And they are "bug free"? :) > >Note that Junior5 pruned under promotions in it search and in I think that in >more than 99% of the games it caused no problems. but in 1% it caused it to blunder. The more you prune, the more those probabilities add up... > >Most of the problems with pruning under promotions is underpromotion to a >knight. >pruning underpromotion to a bishop or rook may cause problems only when there is >a stalemate combination and if there are a lot of pieces in the board there is >no chance for stalemate. > >if a rule cause problems only in 0.00001% of the games then you can safely have >1000 similiar rules with no practical problem. > >Uri Assume you are right 99.99% of the time. See what happens when you add together 1000 rules. Just compute .9999 ^ 1000 and you might be amazed at the chance you get thru that maze with no "error"... The chance is 1 in 10 that you will "blow it". And 1000 rules isn't going to be even _close_ to what you need.
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