Author: Robert Hyatt
Date: 18:31:09 11/11/02
Go up one level in this thread
On November 11, 2002 at 12:04:03, Uri Blass wrote: >On November 11, 2002 at 10:28:33, Robert Hyatt wrote: > >>On November 11, 2002 at 01:10:23, Uri Blass wrote: >> >>>On November 10, 2002 at 23:53:19, Robert Hyatt wrote: >>> >>>>On November 10, 2002 at 22:38:03, Jeremiah Penery wrote: >>>> >>>>>On November 10, 2002 at 21:29:43, Robert Hyatt wrote: >>>>> >>>>>>On November 10, 2002 at 21:15:07, Jim Bumgardner wrote: >>>>>> >>>>>>>Which of these strategies for "think on opponent's time" makes more sense? >>>>>>> >>>>>>>A) To only search the top-move from the principle variation. If >>>>>>>the opponent makes that move, continue searching, otherwise reset and >>>>>>>search again. >>>>>> >>>>>>This is the _only_ way to do it. I've explained this many times, but it >>>>>>is probably time to go it again... >>>>> >>>>>For the general case. But it shouldn't be hard to find situations where it's >>>>>very easy to tell the ponder move is probably wrong. In those cases, it's >>>>>obvious, IMO, that switching to a different ponder move would help. >>>>> >>>>>One possible scenario is when the ponder move keeps failing high - either the >>>>>ponder move is wrong, or you ponder some other move and you'll find the >>>>>fail-highs again anyway if they play the original ponder move. Otherwise, >>>>>you'll have a better chance of pondering on a better move. You could always >>>>>save the result of the first ponder search just in case. >>>> >>>> >>>>That is a good point of course. If you get the fail high _before_ using the >>>>"target time" then you can safely switch to pondering something else, knowing >>>>you will have time to find the "fail high" again, if the opponent makes the >>>>expected move. >>>> >>>>The bad side might be that you don't fail high until you are beyond your target >>>>time, so that if you start pondering something else, you might not be able to >>>>find the fail high for real if the opponent actually makes that move... >>> >>>You assume here that you are going to forget the fail high. >>> >>>You can rememeber the move that you want to play against the expected move in >>>case of fail high and continue to search other moves and when the opponent plays >>>the expected move you can play the move that you remember in 0 seconds. >> >>Yes, although I am trying to adhere to the KISS principle here. The above >>would work well, but it would introduce additional complexity and the >>opportunity for bugs. But it might be worth it too... >> >>> >>>I also believe that the best strategy is not to ponder only on one move but to >>>have a lot of threads(for every legal move of the opponent a different thread) >>>and to give different priority for different moves. >> >>How about some math to show how the above is going to be better than pondering >>one move that is correct over 50% of the time. I don't see any way to improve >>except in special cases such as a terrible fail-high that lets you know your >>opponent probably won't play that move... > >I admit that there is not a big improvement but if you want some math then here >is is: > >What is better? > >Case A:You ponder the expected move 60% of the cases and ponder another move in >40% of the cases > >case B:In the same 60% of the cases you use 90% of the time for the expected >move. >In the rest of the 40% of the cases you use 30% of the time for the move that is >going to be played. > >0.6*0.9+0.4*0.3=0.66>0.6 > You are making assumptions that are unsound. I am _certain_ that I ponder the correct move 50% of the time (actually significantly better than that, but 50% will do for now). I am _also_ certain that I can't be sure that in your case B that I can use 30% of the time for the move that is going to be played. How can I know that until it is played? I can't. And if the probability that the best move from the search is right 50% of the time, it is wrong 50% of the time. How are you going to be so accurate that you can get _the_ move that will be played to ponder in your above approach? I don't see how it is possible. If the "best move" is wrong 50% of the time, then _clearly_ the second_best move will be wrong _more_ than 50% of the time. If we had a way to get the second-best move anyway... > >Uri
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