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Subject: Re: new thoughts on verified null move

Author: Omid David Tabibi

Date: 20:19:38 11/23/02

Go up one level in this thread


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?!

>
>>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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