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Subject: Re: finding when a move is obvious.

Author: Robert Hyatt

Date: 09:28:54 04/14/04

Go up one level in this thread


On April 14, 2004 at 03:32:17, Peter Fendrich wrote:

>On April 14, 2004 at 02:21:41, Christophe Theron wrote:
>
>>On April 14, 2004 at 00:26:34, Eric Oldre wrote:
>>
>>>After you find the 1st "good" move don't you narrow the alpha beta window so
>>>that you don't know how much worse the 2nd move is, only that it is not as good
>>>as alpha?
>>>
>>>Or do you not narrow the window at the root node? that seems like it would
>>>greatly expand your search tree.
>>>
>>>or am i missing something else?
>>>
>>>
>>>On April 14, 2004 at 00:09:24, Robert Hyatt wrote:
>>>
>>>>Simple idea:
>>>>
>>>>a move is "easy" and can be made after using less than the planned time limit if
>>>>and only if
>>>>
>>>>1.  estimated score for first root move is way higher than the second move.  IE
>>>>say 2.00 better.
>>>>
>>>>2.  This is a recapture.  IE opponent just captured a piece of ours and we are
>>>>recapturing on the same square.
>>>>
>>>>Other types of "easy" moves have higher risk to stop the search early...
>>>>
>>>>
>>>>>
>>>>>Thanks,
>>>>>Eric Oldre (new chess programmer)
>>
>>
>>
>>I think that by "estimated score", Bob means the score returned by a SEE (Static
>>Exchange Evaluator), not by a real search.
>
>I shouldn't tell what Bob means but I doubt this is right...
>I wouldn't rely on a SEE for such decisions when the first few iterations will
>give you a much more reliable score quite fast and you could use the score for
>previous move in the game as a staring point.
>If the score fulfills the conditions mentioned by Bob from the first iteration
>and up to lets say 1/2 the total time alotted for that move then stop and make
>the move. (Given that the time allocated for a move is just a function of
>remaining time and number of moves left)
>/Peter
>

I don't use SEE.  I use a call to Quiesce() for each root move to get an
approximate score for sorting them...

It still isn't perfect, but it is not bad...

>>
>>
>>
>>    Christophe



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