Author: Bob Durrett
Date: 07:42:41 11/11/02
Go up one level in this thread
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. > > > > >>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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