Author: Frank Schneider
Date: 12:09:05 02/10/03
Go up one level in this thread
On February 09, 2003 at 23:03:43, Charles Roberson wrote:
>
> I have more tests to do, but this seems to work.
> I began to wonder how close the first and second search values are in pvs.
> I ran some tests and the seem relatively close. So, I adjusted the algorithm.
>
> Normal algorithm:
> v = -Search(-alpha-1,-alpha); // first value
> if ((v>alpha) && (v<beta))
> v = -Search(-alpha,-beta) // second value
>
> Adjusted algorithm:
> v = -Search(-alpha-1,-alpha);
> if ((v>alpha) && (v<beta))
> {
> int nalpha, nbeta;
> nalpha = v - (pawnvalue>>3);
> nbeta = v + (pawnvalue>>3);
Hi,
this can also be done at the root: instead of opening the aspiration
window to (fail_high_score, infinite) just open it to (fail_high_score,
fail_high_score + delta).
Frank
> v = -Search(-nbeta,-nalpha);
> if ((v<nalpha) || (v>nbeta))
> v = -Search(-beta, -alpha);
> }
>
> So far this produces a 3 to 5 percent speedup in NoonianChess.
>
> What does everyone think?
>
> Charles
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