Author: Vincent Diepeveen
Date: 10:14:46 03/01/01
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On February 28, 2001 at 10:24:22, Robert Hyatt wrote: >On February 27, 2001 at 10:49:29, Uri Blass wrote: > >>On February 27, 2001 at 10:07:31, Robert Hyatt wrote: >> >>>On February 27, 2001 at 08:24:14, Jorge Pichard wrote: >>> >>>>I believe that the drawish move was Qe3! instead of the Qxc6? Can somebody >>>>post the FEN string that produce the graphical position for me. Plus I wonder >>>>what program save the draw in the shortest time possible? >>> >>> >>>None can see this. It is a 60+ ply repetition. Way beyond anything we can >>>see today. >> >>We need to test all the programs in order to say that none can see it. >> >>Some programs like dark thought are not available so we cannot know that none >>can see it. >> >>The fact that it is 60 ply repetition is not a proof that none can see it >>because programs only to need the right extensions to see the relevant 60 plies >>forward. >> >>If you are wrong then testing only one program is enough to prove it. >> >>Uri > > >Here I disagree. I fully understand what chess programs are doing in the >tree, and I have a good grasp of the exponential search issue. While what >you say is _possible_, it may also be possible to exceed the speed of light >in space travel one day. But _not_ with today's technology. Same for the >search issue. To reach 60+ plies in that position would require some >impossibly accurate extensions... because if they are triggered in the _wrong_ >positions, the tree will explode to an impossible-to-search size. If a chess >program could search this position with an effective branching factor of 2, >it would still have to overcome the issue of 2^60 to get deep enough to find >that draw. > Suppose i hardcode it in search for this position: "if no draw score found for black then extend moves to the white king, not caring for queen side". That finds it pretty quick. Note the draw here is like 18 plies of search at most. So a bit more lucky with extensions and i find it already. Will try a shot today. Note that the line is *not* 60 ply. Assuming check is extended by 1, then this position is about 21 ply or so if you do some checks in qsearch that is... Greetings, Vincent >It would be more likely to recognize potential perps by static analysis, because >the actual tree here is simply _impossibly_ big. Humans don't solve it by >searching until they _see_ the repetition... they solve it by searching until >they reach a position where they recognize that a repetition is unavoidable. >Programs don't yet work like that. I am not sure they will for a _long_ time.
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