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Subject: Re: Is it possible for pondering to have a slightly negative impact?

Author: Tony Werten

Date: 00:33:06 08/11/01

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On August 10, 2001 at 16:04:18, Artem Pyatakov wrote:

>I just implemented pondering in my program, but it seems that this has a
>negative effect on average search depth in games. Here is my reasoning:
>
>1) My engine is not very strong, so especially in games against humans, the
>percentage of the times when it ponders correctly in "indecisive positions" is
>low.
>(Aside question: What approximate percentages do programs like crafty have?)

I'm quite sure it changes with the opponent. When I played Patzer last time, I
think we predicted each other moves about 90% of the time. The only reason for
not moving immediately was that after predicting the right moves a couple of
times, the time spend would not be long enough. (the game ended in a draw)

>
>2) So, let's say the ponder was incorrect. Wouldn't the ponder process have
>ended up loading a lot of "junk" into the hash table and the history table?

If you're afraid of that, copy the whole stuff before pondering and copy it back
after an unexpected move.

>
>Does this even sound reasonable? Has anyone run into this? Or is this most
>probably a bug? Any suggestions/comments are appreciated.

From my own experience, I know it is possible to make a lot of mistakes in
pondering :(

Tony

>
>Thank you.
>
>Artem



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