Computer Chess Club Archives




Subject: Re: Proving something is better

Author: Omid David Tabibi

Date: 12:58:09 12/18/02

Go up one level in this thread

On December 18, 2002 at 15:49:14, Uri Blass wrote:

>On December 18, 2002 at 15:43:56, Omid David Tabibi wrote:
>>On December 18, 2002 at 14:31:21, Bruce Moreland wrote:
>>>On December 18, 2002 at 11:29:37, Omid David Tabibi wrote:
>>>>On December 18, 2002 at 11:23:38, Gian-Carlo Pascutto wrote:
>>>>>On December 18, 2002 at 11:15:01, Omid David Tabibi wrote:
>>>>>>I further don't understand why all the fire is directed at me; fixed depth
>>>>>>comparisons are the common accepted comparison methods, which are completely
>>>>>>hardware independant.
>>>>>>For the most recent examples take a look at Heinz and Plaat's numerous >articles, all of which were conducted in fixed depth.
>>>>>I would think that the best research is the one that improves upon
>>>>>the mistakes of previous ones.
>>>>I am yet to be convinced that the methodology practiced by Hyatt, Schaeffer,
>>>>Marsland, Buro, Plaat, Heinz, and others, is mistake.
>>>I have complaint with how this is applied, sometimes.
>>>One type of test involves making the tree smaller, period, while doing the same
>>>kinds of work.  If Schaeffer is going to test the history heuristic, that's
>>>great -- if the tree is smaller, it's a win, because if you can consistently do
>>>the *same* stuff in fewer nodes, that's always good.
>>>The only possible criticism I can have of something like this is if it doesn't
>>>use enough test positions.
>>>If you are trying to prove that something sees more, what does seeing more mean?
>>> You can blow the tree size up by extending everywhere, and you will see more in
>>>a given depth.  But depth is not the proper measure, since a larger tree size
>>>will also take more time to search.
>>>If you want to "improve" a chess program in this manner, just incorporate a
>>>two-ply search into your eval function.  You'll find stuff two plies sooner.
>>>The only reason that your experiment shows that VR=3 is better than R=2 is that
>>>the solution set was bigger *and* the node counts were smaller.  You can
>>>*assume* from that that the times are also reduced.
>>>You can't make these assumptions about R=3 as compared with VR=3.
>>>And for that
>>>matter, you can't make them about R=3 as compared with R=2, given the data you
>>>Your data strongly implies that R=3 is better than R=2.  That is disturbing,
>>>since your paper regards the superiority of R=2 over R=3 as axiomatic.
>>I didn't intend to reinvent the cycle. It has already been shown elsewhere that
>>std R=2 is superior to std R=3.
>if std R=2 is superior to std R=3 for program X when  VR=3 is superior to std
>R=2 for program Y then it does not prove superiority of  VR=3 to std R=3
>I believe that R=2 is not superior to R=3 for Genesis and I remember that even
>before the article you claimed that R=3 is better than R=2 for genesis at long
>time control.

No, I claimed that for longer time controls the superiority of std R=2 over std
R=3 is not that significant. But I never said that std R=3 is better than std
R=2 under any time control.


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