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Subject: Re: new thoughts on verified null move

Author: Omid David Tabibi

Date: 18:24:08 11/23/02

Go up one level in this thread


On November 23, 2002 at 21:09:36, Tony Werten wrote:

>On November 23, 2002 at 20:52:01, Omid David Tabibi wrote:
>
>>On November 23, 2002 at 20:00:15, Tony Werten wrote:
>>
>>>On November 23, 2002 at 11:11:16, Christophe Theron wrote:
>>>
>>>>On November 23, 2002 at 09:22:37, jefkaan wrote:
>>>>
>>>>>oops, wasn't finished yet..
>>>>>
>>>>>>are done by using the results of the positional eval
>>>>>>to prune the q-search,
>>>>>and there using only material eval
>>>>> (haven't tried it out yet, and wouldn't
>>>>>know how to do it, but it's only an idea,
>>>>>you know.. to explore options of
>>>>>more effective branch factor reducements
>>>>>and efficient programming (besides
>>>>>lousy solutions as inline assembler
>>>>>and bitboards..
>>>>>:)
>>>>
>>>>
>>>>
>>>>Yes Chess Tiger does much more pruning than known (published) techniques.
>>>>
>>>>I think other top programs do it also.
>>>>
>>>>I still fail to see why the efficiency of an algorithm depends on what your
>>>>QSearch does.
>>>>
>>>>If your pruning algorithm is good, it will increase the strength of the program
>>>>regardless on how good your QSearch is.
>>>>
>>>>If your QSearch is smart, then it will increase the strength even more.
>>>>
>>>>I don't like the idea that some algorithms that have almost nothing to do with
>>>>each other would have such an influence on each other. It is indeed possible and
>>>>it probably happens all the time, but it's hard to work with such hypothesis in
>>>>mind.
>>>>
>>>>I think it's better to first assume that the kind of QSearch you do will not
>>>>interfere with the quality of the pruning algorithm used before the QSearch.
>>>>
>>>>If your QSearch sucks, it's not because you are doing a lot of pruning in the
>>>>"full width" part of the search. It's because it sucks.
>>>
>>>The paper does prove that the more your (q)search sucks, the better your pruning
>>>algoritm seems. But that's not really news.
>>>
>>
>>Does it prove that?! No, it's just my impression based on the data gathered so
>>far. Maybe a reduction of 2 (instead of 1) in case of fail-high report, will
>>work better in programs with heavy extensions and quiescence.
>
>A reduction of 20% seems to be working best in XiniX ( heavy qsearch).

What do you mean by 20%? (you used a reduction of 1 or 2 in case of fail-high
report?)


>I'm
>interessed in your idea. It's commented out in my program now, but not deleted.
>I still have to play with it some more.
>
>Despite of the negative comments you had, I don't think it's a bad idea. I'm
>just not convinced yet it's a good one.
>

It took me several months of experiments to get convinced. After a little more
tuning and playing with different reduction values (1 or 2), I believe you will
be convinced too ;-)


>Tony
>
>
>
>>
>>
>>>Tony
>>>
>>>>
>>>>
>>>>
>>>>    Christophe



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