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Subject: Re: Parallel search article RBF

Author: Vincent Diepeveen

Date: 10:03:12 09/11/02

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On September 11, 2002 at 12:57:20, Vincent Diepeveen wrote:

>On September 11, 2002 at 11:41:13, Robert Hyatt wrote:
>
>>On September 11, 2002 at 07:33:56, Gian-Carlo Pascutto wrote:
>>
>>>On September 11, 2002 at 00:36:21, Dann Corbit wrote:
>>>
>>>>Since the speedup was almost linear, I would say it is better than any [other]
>>>>known method.
>>>
>>>It's 7-15 times slower than alphabeta.
>>>
>>>If you start out by being 7 times slower, it's not hard to get good speedups.
>>>
>>>--
>>>GCP
>>
>>
>>that is the point.  And it also takes a huge amount of memory since best-first
>>has to store the whole tree as it is traversed.
>
>They didn't do this at all. In fact they search in a very pathetic
>way, they search using a selfdefined form of bestfirst search.
>
>There is no garantuee they find anything. Obviously such approaches work
>for tricks with a small b.f., I find their parallel speedup very bad,
>considering the way they search is ideally parallellizable.
>
>Lineair i'd say.
>
>It is not clear to what crafty version they compared and at what machine.
>I get on average over 10 times faster times with crafty to solve something.
>
>From memory i say their box had 500Mhz cpu's, crafty was probably run
>on a box of around 200Mhz i would estimate.
>
>Best regards,
>Vincent

I need to add an important note. in chess they compared search times,
which in itself looks like a good idea. However they compared in othello
not search times but number of nodes. Their reported nodes a second
doesn't seem very fast to me (a few hundreds of evaluations a second),
and more important is that they compared with 'jamboree' search which
they implemented themselves using Cilk.

I've been never a big fan of Cilk here. Claiming it is ideal to 'simulate'
things at 1 processor is a weird statement to me. It is the typical
academic publication where based upon 2 numbers they had by tossing
a coin, they conclude things.







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