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Subject: Re: Null-Move: Difference between R = 2 and R = 3 in action

Author: Sune Fischer

Date: 07:35:44 07/20/02

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On July 20, 2002 at 09:20:41, Uri Blass wrote:

>On July 20, 2002 at 08:38:52, Sune Fischer wrote:
>
>>On July 20, 2002 at 08:13:44, Gian-Carlo Pascutto wrote:
>>
>>>On July 20, 2002 at 08:04:01, Sune Fischer wrote:
>>>
>>>>I think it matters "a factor of 2".
>>>>
>>>>1) it helps you to prune
>>>>2) you get better evaluation in the upper plies when you can return a score
>>>>based on a deeper search.
>>>>
>>>>number one will show itself directly because you iterate deeper, the second one
>>>>you don't "see", but it does improve depth along some branches in the same way.
>>>
>>>1) I get +- 10% hash hits (and less prunes) in typical middlegame. Not enough to
>>>matter a factor of two (but I didnt check this so not 100% sure).
>>>
>>>2) Uh?
>>
>>You have 1 ply to go, you probe and get a hit based on a 10 ply search.
>>
>>Or, what is perhaps more likely, a 6 ply result when you only had 4 plies to go,
>>that is still 2 more plies of accuracy and you also prune/transpose at the same
>>time.
>
>I doubt about the accuracy.
>
>You may remember a draw score and use it
>when practically it is not a draw because
>the draw score is based on previous positions and when
>you get the same position again the previous positions
>are not the same.
>
>Uri

I don't store repetition draws in the hashtable, but the other way around, that
the result _could_ be draw when I return something else, is just unavoidable
AFAIK. But I doubt that causes a lot of errors.

-S.



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