Author: Robert Hyatt
Date: 12:44:55 11/11/02
Go up one level in this thread
On November 11, 2002 at 10:42:41, Bob Durrett wrote: >On November 11, 2002 at 10:24:26, Robert Hyatt wrote: > >>On November 11, 2002 at 08:21:01, Andreas Guettinger wrote: >> >>>I would think that engine moves are easier to predict than human moves. I don't >>>have the statistics to support this, it is simply based on experience following >>>engine-human matches. >>> >>>So what may be a good strategy for one must not be so for the other. Predict >>>engine moves in 1/2 of all the cases might be possible, but for humans moves I >>>would suspect that it is less than 1/4 of all the cases. So possibly: >>> >> >> >>Depends. In games vs GM players, Crafty averages predicting correctly 70-80% >>of the time. In games vs computers, this might drop to 60-70 for whatever >>reasons. But it is generally > 50% for all cases until you start throwing in >>very weak opponents, as it drops to almost nothing in those cases, for obvious >>reasons. :) > >What's that? : ) > >Amateur chess is better than GM chess because there are more surprises. > >Bob D. Yes. And more blunders too. :) > >> >> >> >> >>>Strategy A) in engine tournaments. >>> >>>Strategy B) in human tournaments. >>> >>>Andreas >>> >>> >>> >>>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... >>>> >>>>Suppose you predict your opponent's move correctly only 50% of the time. >>>>And it should be pointed out that this is a _low_ estimate from thousands >>>>of observed games (via log files). This means that 1/2 of the time, you will >>>>predict correctly and when your opponent moves, you have an instant response >>>>ready. 1/2 of the time you get to think for free. >>>> >>>>Suppose you choose to search the top three moves instead of just the first one. >>>>When your opponent has moved, you have spent 1/3 of the total time on each move. >>>>You save 1/3 of the time. And that is worse than saving 1/2. If you only >>>>search the top 2 moves, you will save 1/2 of the time, _if_ the move played is >>>>one of those two, but occasionally it won't. >>>> >>>>It is really simple to see why searching only the best move is the right >>>>idea. I could think of a few cases where I might vary this, such as where >>>>my target time is 3 minutes and my opponent searches for 12 minutes. Do I >>>>want to search one move for 12 minutes, or do I want to take a chance and >>>>use 1/2 of that time (say) to search for an alternative best move? Tough to >>>>say, and although I have tried such ideas many times, I have always come back >>>>to searching what I consider the best move only. And since 50% is a low >>>>prediction percentage, searching one move actually is even better than the >>>>above pessimistic analysis. >>>> >>>>> >>>>>B) To search all possible moves the opponent might make. When the opponent >>>>>moves, reset and search again (but faster, since the hash tables have been >>>>>seeded). >>>> >>>>see above why this is not so good... >>>> >>>> >>>>> >>>>>C) Some other strategy? For example, to use A) only if the top move is >>>>>'singular' (has a significantly better score). >>>>> >>>>>What strategy does your chess engine use? To date, I have been using "A", >>>>>but I am beginning to think that "B" or "C" might be better. >>>>> >>>>>- Jim
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