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Subject: Re: Verified Null-Move Pruning, ICGA 25(3)

Author: Omid David Tabibi

Date: 18:47:00 11/26/02

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On November 26, 2002 at 20:02:06, Robert Hyatt wrote:

>On November 26, 2002 at 16:21:00, Omid David Tabibi wrote:
>>On November 26, 2002 at 15:58:06, Gian-Carlo Pascutto wrote:
>>>On November 26, 2002 at 15:55:56, Omid David Tabibi wrote:
>>>>So it is reasonable that on every program starting from a certain depth >adaptive null-move pruning will always construct a smaller search tree.
>>>Don't you mean the other way around?
>>Yes :-)
>>Starting from a certain depth, verified null-move pruning will always construct
>>a smaller search tree than the adaptive one.
> I am doing some testing now.  First thing I noticed is that for WAC, the
>measurement went down very significantly for your algorithm.  And I have not
>anything such as turning null-move off when low material happens, since your
>idea will
>catch the zug problems.
>I am playing a match between old and new, and at the moment the result is
>5 wins, 2 losses, 13 draws, new version is ahead.  Not enough games, but it is
>More as I get more info...

Definitely interesting...

BTW, since Crafty has strong extensions, I suggest that you also try reducing
the depth by 2 plies (instead of 1) on fail-high reports. In the "Conclusions"
section I reported that in this case the tactical strength was lower than std
R=2 on occasions; but considering the fact that its search tree was also far
smaller, it is still an interesting option.

In the paper, my goal was to present an algorithm tactically stronger than std
R=2, and with smaller search tree. In practice however, other values might work
even better.

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