Author: Christophe Theron
Date: 19:56:04 01/23/00
Go up one level in this thread
On January 23, 2000 at 03:35:35, Bruce Moreland wrote:
>On January 23, 2000 at 02:51:55, Amir Ban wrote:
>
>>The results can be disregarded on these grounds of course, but it's also true
>>that the results, as reported, can be dismissed as being in contradiction to the
>>DB/DT public record, and to common sense in general.
>
>Here are some ideas about what might have happened in those games:
>
>1) DB Jr may have beaten those programs purely through eval function
>superiority.
>
>2) It may have won because of superior search.
>
>3) There may have been a poor comparison between node rates, resulting in DB Jr
>having a massive hardware advantage.
>
>4) The whole thing may be ficticious.
>
>5) Random chance.
>
>6) Something I haven't thought of yet.
>
>Bob may go nuts because I included #4. I don't believe that #4 is true, but
>someone can always claim that it is, and there is no obvious evidence that can
>be used to refute this claim, which disadvantages us who want to understand this
>rather than argue religion and conspiracies all day.
>
>#1 is what we are expected to believe, I thought that is what this test was
>supposed to measure. I have a very hard time with this one. I don't believe
>there are any terms that in and of themselves would result in such a lopsided
>match. I don't believe that I could set up my program to search exactly a
>hundred million nodes per search, and play it against the best eval function I
>could possibly write, also searching a hundred million nodes per search, and
>score 38-2.
I totally agree with you here.
>Could I be convinced that #1 is true? You bet! Will I accept that #1 is true
>based upon faith in the reputations of Hsu and Campbell? With all due respect,
>not a chance. I don't think anyone should be expected to be so trusting in a
>field that's even remotely scientific.
>
>It would also be hard to accept #2, since DB is supposedly not optimized for
>short searches. And I believe that you've ruled out #5, which seems a sensible
>thing to do.
I haven't followed the discussion, but on short searches, how many plies deeper
do you need to compute to get a 38-2 result?
My guess is that 3 plies and a bit of luck would do it easily. You need to be
100 to 200 times faster than your opponent to achieve this (less if you have a
decent branching factor, but DB has not).
I think this is a very easy experiment to do.
DB is definitely optimized for short searches, if you think about it.
It has the best NPS of all times, and probably one of the worse branching factor
you can imagine, because of this crazy singular extension and lack of null move
(or related) optimization.
So I would say that compared to modern microcomputer programs it would perform
worse and worse as time control increases.
Maybe I missed something?
Christophe
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