Author: chandler yergin
Date: 15:21:06 01/13/05
Go up one level in this thread
On January 13, 2005 at 12:46:40, Robert Hyatt wrote: >On January 12, 2005 at 20:57:40, chandler yergin wrote: > >>On January 12, 2005 at 20:33:25, Dann Corbit wrote: >> >>>On January 12, 2005 at 20:25:24, Uri Blass wrote: >>> >>>>On January 12, 2005 at 19:56:25, Dann Corbit wrote: >>>> >>>>>On January 12, 2005 at 19:37:29, Steve Maughan wrote: >>>>> >>>>>>Dann, >>>>>> >>>>>>>Things that seem impossible quickly become possible. >>>>>> >>>>>>I recon about 300 years before a computer will solve chess. This assumes >>>>>> >>>>>>1) 10^120 possible positions >>>>> >>>>>This is far, far too large. Chess positions have been encoded in 162 bits, >>>>>which puts an absolute upper limit at 10^58 (and it is probably much less than >>>>>that). >>>>> >>>>>>2) Alpha-beta cutting this down to 10^60 sensible positions >>>>> >>>>>The incorrect first assumption renders this and all following assumtions as >>>>>moot. >>>> >>>>The second assumption is also not correct. >>>> >>>>By the same logic alphabeta can cut less than 2^30 positions in KRB vs KR to >>>>2^15 positions but it does not happen and solving some KRB vs KR position with >>>>no KRB vs KR tablebases is not something that you need 2^15 nodes for it. >>> >>>No. The second assumption would be true if the first was true. This was >>>formally PROVEN by Donald Knuth. In a perfectly ordered alpha-beta solution >>>tree, the number of nodes is proportional to the square root of the nodes in the >>>full tree. >>> >>>If there were 10^120 in the full tree, then about 10^60 would be in the solution >>>tree. >>> >>>It can be less than that. >> >>It "Can't be LESS than that! >> >> But it cannot be more. >> >> >>It Certainly CAN! >> >>In any TREE.. the TREE ONLY represents "What HAS Been PLayed." >>REFUTE THAT! >>Can't HUH? >> >>Give it up! > > >this is going nowhere. DC is correct here, and the math is there to support >him. AB gives a minimal tree size with perfect ordering. If you do perfect >ordering, the AB tree will _not_ be larger than the usual estimate. If you use >hashing, it can be even smaller since you can avoid searching duplicate >sub-trees that normal alpha/beta would search... > >In the above context, the tree does not represent "what has been played", It >represents everything that has or can possibly be played in this particular >position and its successors. NONSENSE! A TREE is "ONLY" what has been Played" Are you one of the "DUMB, DEAF, & BLIND"? I thought you had some Common sense! Guess I was Wrong! > >Time to move on...
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