Author: Angrim
Date: 21:48:17 05/11/01
Go up one level in this thread
On May 11, 2001 at 22:24:21, Robert Hyatt wrote: >On May 11, 2001 at 15:49:19, Angrim wrote: > >>On May 11, 2001 at 03:29:43, Dann Corbit wrote: >> >>>On May 11, 2001 at 01:49:03, Angrim wrote: >><snip> >>>>If your goal is to determine how hard it is to solve chess, then yes. >>>>Rather then go into a lengthy rant here, let me give an example. >>>>The following position has pawns advanced a total of 4 squares, so >>>>subtract 4*50 from the max depth, and your math suggests that there are >>>>38^(5900 -200) total games of chess that can result from this position. >>>>However, the position is trivial. No need for sqrt(38^(5900 -200)) >>>>positions to be searched or stored... >>>> >>>>[D]rnbqkbnr/pppp1ppp/4p3/8/6P1/5P2/PPPPP2P/RNBQKBNR b KQkq g3 0 2 >>> >>>Yet there are many quintillions of quintillions of qintillions of games that can >>>sprout from here. >>> >>My point being that if your goal is to solve this position, then all >>but 1 of those games is totally irrelevant.\\\\\ > > > >Unfortunately they are _not_. Because you have to _prove_ that the best >move is best. And to the best of my knowledge, there is no "oracle" that >will give us perfect move ordering so it is not just likely, it is highly >probable that the winning move won't be searched first. Maybe it will be >searched by the 1/2 way mark at this play, maybe it will be last. But >if it isn't first, you have a HUGE tree to search first... > >That's the way alpha/beta works... not best-first but alpha/beta... > > did you happen to look at the position? You need to look at exactly 1 line to prove that it is the best line. If you are unlucky you might need to look at 30 or so other lines first to find this line, but my point was that the "many quintillions of quintillions of qintillions of games" that can result from this position are irrelevant. The fact that with worst play games thousands of moves long could result from this line is also irrelevant. Yet, much of the discussion of this subject to this point has been about how many legal games there are, and the max depth of such games. Angrim
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