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

Author: Omid David Tabibi

Date: 03:47:00 11/22/02

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On November 22, 2002 at 06:39:24, Uri Blass wrote:

>On November 22, 2002 at 06:11:54, Omid David Tabibi wrote:
>
>>On November 21, 2002 at 21:21:09, Vincent Diepeveen wrote:
>>
>>>On November 20, 2002 at 17:51:40, Alessandro Damiani wrote:
>>>
>>>'verified' nullmove, or in a different implementation but
>>>same algoritm, with just 1 ply reduction is nearly a fullwidth
>>>search.
>>>
>>>I did with a bigger reduction of course. that's also very
>>>costly compared to R=3. This was just an experiment carried
>>>out years ago when it was described in ICCA journal. Now
>>>we have same algoritm in a few lines diff algorithm.
>>>
>>>I do not see how Omid can just suffer 50% slowdown of his
>>>algorithm. Note he only publishes search depths not
>>>search times. That is wrong.
>>>
>>>You must publish search times.
>>>
>>
>>You understand nothing out of research, and this is demonstrated by your call
>>for comparing search times.
>
>1)I understand the point that time can be different but usually comparison of
>times is what I am interested and I trust my computer to be almost at the same
>speed so the error is small.
>
>Different algorithms may change the number of nodes per second and the
>difference may be dependent on the position so comparison of nodes to get the
>same depth is also not correct.
>

If you are testing this algorithm on your program, then use fixed time
comparisons. But as someone who wanted to publish as generic results as
possible, I couldn't publish time dependant results.


>2)It is clear for me that your algorithm is clearly better than R=2.
>It is not clear if it is better or worse than R=3 but I agree that with some
>tuning it should be better than R=3.
>
>Maybe research is going to be enough for it.
>I do not see how research is about detecting zugzwangs.
>
>The algorithm seems to detect zugzwangs also without research and only searches
>them to reduced depth.
>

Zugzwang detections through the re-search, is just a bonus ;-)
The core of the algorithm is the middlegame enhancement.


>Uri



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