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Subject: Re: finding when a move is obvious.

Author: Eric Oldre

Date: 11:38:57 04/14/04

Go up one level in this thread


Thanks to everyone who contributed to this thread, It's helped my understanding
a lot.

I think I'll use the suggestion below and call queis(-INFINITY,INFINITY) for
each root node move to find the estimated score before starting iterative
deepening.

Eric Oldre


On April 14, 2004 at 12:28:54, Robert Hyatt wrote:

>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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