Author: José de Jesús García Ruvalcaba
Date: 08:53:55 08/01/01
Go up one level in this thread
On August 01, 2001 at 09:08:08, Gordon Rattray wrote: >On July 31, 2001 at 22:35:26, Christophe Theron wrote: > >>On July 31, 2001 at 19:18:36, Roy Eassa wrote: >> >>>On July 31, 2001 at 15:26:08, Ed Panek wrote: >>> >>>>On July 31, 2001 at 15:24:48, Roy Eassa wrote: >>>> >>>>>On July 31, 2001 at 15:21:17, Ed Panek wrote: >>>>> >>>>>>Lets say I have a move generator that selects a random move every time it is its >>>>>>turn. What are the odds against it drawing/winning a game? Is it less likely >>>>>>than winning a game of Keno with all the correct numbers picked? >>>>>> >>>>> >>>>>Is the opponent Kramnik or Deeper Blue? Or a human rated 400? Or another such >>>>>"random" program? I think this matters. >>>> >>>>Lets try a random opponent first...and then Kramnik >>>> >>>>Ed >>> >>> >>>Obviously, the chance of beating another random-playing program is 50% (not >>>counting draws). >> >> >>It depends how is programmed the random opponent. >> >>If the opponent just picks a move at random, odds are 50%. >> >>If the opponent is a program that does some sort of of alpha beta on a tree >>where the leaves receive random numbers, this opponent will win very often. >> >>That means: a random evaluation function is much stronger than a program >>choosing a move at random. > >Do you assume that a move leading immediately to checkmate, stalemate, etc. >returns a meaningful (non-random) value? If not, I don't understand why your >claim holds true? I assume a "random evaluation function" to be random for >*all* positions. > >Gordon > Even with a pure random non-constant evaluation, deeper search helps (but I would assume that checkmates and other ways to end the game are recognised and properly evaluated). The reason is that even a random evaluation will favour moves which increase the own mobility (as long as the search depth is bigger than two) and decrease the opponent's mobility (as long as the search depth is bigger than one). And mobility is a positional factor, taking it in account is better than pure random play. By "favouring certain moves" I mean that those moves have a higher probability of being played as the other moves, not that they will always be played. Pure random play is equivalent to a random evaluation after a 1-ply search, so mobility does not count. José. > >> >>This does not answer your question but probably gives food for thoughts about >>what randomness means, or is good for. :) >> >> >> Christophe >> >> >> >> >> >> >>>The chance of beating Kramnik or another top-notch grandmaster is so small as to >>>be essentially zero. Perhaps one in (ten to the power of 40). >>> >>>What might be most interesting is estimating the chance of beating an extremely >>>weak human player -- I don't know how low ratings go, but say USCF 400. (I have >>>a friend with a 4-year-old daughter who knows the rules of chess but not much >>>more.) Then the question becomes: how much better (or worse?!) than random are >>>that player's moves?
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