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Subject: Re: new thoughts on verified null move

Author: Tony Werten

Date: 20:36:21 11/23/02

Go up one level in this thread


On November 23, 2002 at 23:19:38, Omid David Tabibi wrote:

>On November 23, 2002 at 23:14:52, Omid David Tabibi wrote:
>
>>On November 23, 2002 at 22:25:02, Tony Werten wrote:
>>
>>>On November 23, 2002 at 22:14:27, Omid David Tabibi wrote:
>>>
>>>>On November 23, 2002 at 21:50:01, Tony Werten wrote:
>>>>
>>>>>On November 23, 2002 at 21:24:08, Omid David Tabibi wrote:
>>>>>
>>>>>>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?)
>>>>>
>>>>>In case of a fail high I reduce the depth with 20%. ( doesn't work in your silly
>>>>>program :)
>>>>>
>>>>
>>>>Anyway, no matter what the reduction is, you are using verified null-move
>>>>pruning, which is good :-) In my paper I just gave a new null-move pruning
>>>>framework; feel free to play with the values that best fit your program.
>>>
>>>It's a no brainer to implement. If it's not bad then it's worth investigating.
>>>
>>>>
>>>>Even better values do exist. I've been working on them for some time and will
>>>>publish them in near future.
>>>
>>>If I might give an advice. For first reviews, send them it to some active
>>>chessprogrammers, and not to academic has beens. It will save you a lot of
>>>typework. ( you have been quite active on this forum lately )
>>>
>>
>>I will. However, after posting a new method, several days of "heavy presence"
>>will always be needed to clear things up and answer the questions...
>>
>>
>>>BTW last time we mailed I concluded your last name was David, were does the
>>>Tabibi come from ?
>>>
>>
>>My full name has always been Omid David Tabibi. But I usually use just David as
>>my last name in informal occasions. After ICGA put my name as "O.D. Tabibi" on
>>their cover, I thought it would be a good idea to use my full name here to avoid
>>confusion.
>>
>
>BTW, it is 6:20 AM in israel and 5:20 AM in Netherlands... I thought I'm the
>only one awake at this part of the world during the night. Why don't you get a
>sleep?!

Birthday of my mother in law. Need more drinks. BTW good morning. I need to give
my son his breakfest in 2.5 hours.

Tony

>
>>
>>>Tony
>>>
>>>>
>>>>
>>>>>In XiniX I have partial extensions (PLY is 32).
>>>>>The addition to your idea is to give big reductions when there is still a lot of
>>>>>searchdepth remaining. So fe when there is 12 ply left I give more reduction
>>>>>than when there's 6 ply left (with a minimum of 1 ply ) That's 6*0,2 is 1,2 ply
>>>>>more. For XiniX that seems to make the difference between a good and a bad new
>>>>>idea.
>>>>>
>>>>>Tony
>>>>>
>>>>>>
>>>>>>
>>>>>>>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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