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Subject: Re: Q: Singular extensions

Author: Antonio Dieguez

Date: 19:38:45 01/05/04

Go up one level in this thread


On January 05, 2004 at 19:48:25, Bas Hamstra wrote:

>>>Here is what I tried (idea from Bruce I believe):
>>>
>>>Before you search all moves (after nullmove) you search all moves (unsorted)
>>>with D-R
>>
>>  Good point I had missed :)
>>  I was doing an expensive D search with (Alpha-Margin,Alpha-Margin+1) and if
>>only one move failed high, search it again with (Alpha,Beta) extended 1 ply.
>>
>>>and check if there is one and only one move with a score above alpha
>>>*and* above Alpha-Margin.
>>
>>  So if I get it right, you search all moves with D-R and a null window around
>>Alpha-Margin. If only one move fails high, then search it again with D-R and a
>>null window around Alpha. If it fails high again, then that move is extended.
>
>It did not do this, but your idea might be better. I did one single pass with
>window(Alpha-M, Alpha) and simply counted the results.

hi

I don't know if you did it or if it makes big difference, but now that i think
of it, when searching with a window that includes ranges that are worth the same
(areas XYZ, like Alpha-M+1 to Alpha-1 in your window above) there is an
optimization like this, at the top of search. Don't ask me what is best.

if (alpha is in an area XYZ)
{
    alpha = higher value in area XYZ;
    if (alpha>=beta)
    { return beta; }
}

if (beta is in an area XYZ)
{
    beta = lower value in area XYZ;
}



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