Author: Robert Hyatt
Date: 20:42:31 09/27/01
Go up one level in this thread
On September 27, 2001 at 17:48:32, Peter Fendrich wrote: >On September 27, 2001 at 15:12:43, Roy Eassa wrote: > >>On September 27, 2001 at 12:13:10, Peter Fendrich wrote: >> >>>On September 26, 2001 at 21:45:46, Robert Hyatt wrote: >>> >>>>On September 26, 2001 at 20:32:58, Dann Corbit wrote: >>>> >>>-- snip -- >>> >>>>If you correctly predict your opponent's move at least 50% of the time, or >>>>more, then the way we currently ponder can _not_ be improved on. >>> >>>I don't agree if that's what you really mean. "can _not_ be..." is hard to prove >>>in this case. In theory at least you can do better. The _average_ hit rate is >>>>50% >>>If you know that this hit rate vary with different circumstances you will find >>>out different hit rates. If we could separate out cases with very low hit rate >>>it might be succesful with another scheme for just these cases. I've never >>>tested this but it would be interesting to see the hit rate for "consistent" >>>FH's (survives several iterations) compared to the rest. The hit rate for >>>pondermoves giving about the same evaluation as before is probably higher (much >>>higher?). >>>I can think of other types of cases as well. >>>Has anyone computed the figures for different cases like this? >>> >>>I would like leave this "can _not_ be..." open until at least some test like >>>this is done. >>> >> >> >>The factor that causes the engine to be unsure of the move it selected to >>ponder, is the SAME factor that makes pondering multiple moves less useful. >> >>If there are several moves that are all about equal, then there are, by >>definition, also several moves among which you must divide your time pondering. >>Thus even if you were only 20% sure of your opponent's move, it still does not >>make sense to split your pondering time because each likely move would then get >>no more than that same 20%. > >Yes, I buy all that. My intention was to oppose to the "it's impossible" >statement. You are talking about some general case. There is no reason why each >move has to be 20% because the first one is. That's why I'm talking about >isolating cases where the other move might be better. Another question is what >happens if the ponder move has only 10% or 5% probability. >I have no proofs that these cases are possible to identify but I'm still open >for it, until I know better... >//Peter The question is, what would cause that 10%. IE this is all speculation since we won't know whether the opponent will match or not, until he makes a move... But based on collected statistics, Crafty _always_ predicts at well over 50% accuracy. And as long as that is possible, I don't see any way possible to better utilize pondering time. Because it will _always_ be right over 50% of the time and save that time. Here is a test scenario: 1. Assume my opponent _never_ predicts my moves correctly. IE crafty is the only one that ever predicts a move. In this case, crafty is the _only_ player that will save any time pondering. 2. Assume Crafty predicts correctly 60% of the time, and the game being played is such that it has one minute per move, fixed, to make it simple. Then it will average saving 36 seconds per move over the game, based on that 60% prediction rate (.60 * 60 seconds). Now, given those two constraints, give me an algorithm that will save more than 36 seconds per move, on average... You can assume anything you want, just so you don't violate the 60% prediction rate already given.
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