Author: Robert Hyatt
Date: 07:24:26 11/11/02
Go up one level in this thread
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. :) >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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