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Subject: Re: Aborting a search

Author: Matthew White

Date: 13:04:21 03/18/03

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On March 18, 2003 at 09:59:00, Robert Hyatt wrote:

>On March 18, 2003 at 04:18:05, Ed Schröder wrote:
>
>>On March 17, 2003 at 21:54:36, Nathan Thom wrote:
>>
>>>Im having troubles trying to figure out what to do with my search results when a
>>>timeout occurs. eg I could have searched 10 plies fully, and am part way through
>>>the 11th ply when time runs out.
>>>
>>>The simplest thing to do is ditch all results from the last incomplete search
>>>and just go with what you had after 10 plies. But this seems a big waste.
>>>
>>>Thoughts?
>>
>>Nathan,
>>
>>It's quite simple, just check the "time_is_up" condition after your "undo_move"
>>call and jump to the place where you climb back one ply in the tree (as if there
>>are no more moves to search on the current ply).
>>
>>My best,
>>
>>Ed
>
>
>This can be a fatal error.  You are at ply=N and have 10 legal moves to search.
>The first is horrible, but the second wins everything.  If you quit after
>searching the first move and return that score, the previous ply may well like
>the move it tried, and since it has now searched every move, it backs the
>score up.  And so forth.  But when the game really enters this path, the
>first move is not actually played by your opponent, he plays the second, and
>the roof falls in.
>
>You have to _not_ back up things from below the root, once you have decided that
>time is up.

What if you finished ply N with a lazy eval instead of the full eval. Would that
solve the problem?

Matt



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