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Subject: Re: History pruning

Author: Harald Lüßen

Date: 11:48:10 02/28/06

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On February 27, 2006 at 22:22:55, Robert Hyatt wrote:
...
>4.  the biggest thing I want to play with is the history values.  I am currently
>"aging" the values between iterations, but what is happening is that the values
>climb faster as the search gets deeper, which tends to make it get more
>conservative as it goes deeper due to the history threshold limiting when
>reductions are done.  Either the history values need to be stabilized, or
>perhaps the reduction threshold needs to climb along with iteration number...
>or something in between...

When I read my history values I always get values between 0 (not good)
and 256 (most often successfull). I do this with saved history values
between 0 and 65536 and an additional maximum value which is always
updated. Then I can return (history * 256 / (maximum + 1)). When maximum
gets too big, all values and the maximum are divided by a factor.
This is not very precise but you can easyly fix the flaws and
find good tuning values for too big and factor.

I do this because I want always be able to use the history
as input value for some formulas like reductions or margins.
Since my engine is not very good this might be a bad idea. ;-)

Is it possible to make history pruning / late move reductions
depend on the whole history value interval or is it important
to use == 0 and != 0 only?

Harald



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