Computer Chess Club Archives




Subject: Re: Proving something is better

Author: Omid David Tabibi

Date: 12:43:56 12/18/02

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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. So I mainly focused on comparison between vrfd
R=3 and std R=2 (as the strongest representitive of Standard Null-Move Pruning).


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