[Beowulf] Re: Beowulf Digest, Vol 15, Issue 16
James.P.Lux at jpl.nasa.gov
Tue May 10 15:44:41 PDT 2005
At 03:37 PM 5/10/2005, Lombard, David N wrote:
> > Actually, the ideal "goal evaluator" is me, looking at the results of
> > several runs and comparing them, then telling the "box" which way to
> > next. As you say, if you could define a goal function with sufficient
> > clarity, then any manner of optimizers could grind away on the problem
> > overnight. Unfortunately, most real design problems have requirements
> > that
> > are a bit fuzzy: Don't make it "too big" or "too flimsy". terms like
> > "flimsy" are hard to encapsulate succinctly in a mathematical
> > (although, gosh, we certainly try, by requiring certain mechanical
> > resonance properties and failure strengths). Much like other things,
> > know them when you see them.
>Hmm, too "big" or "flimsy" have very precise definition based on exactly
>the measures you describe. Such goal functions have been in use in the
>various structural optimizers for years now, e.g., weight, stress
>distributions, deflections, modal responses, &etc.
True, when you have hard specifications. The hard part is negotiating a
relative weight for each of these factors when doing the tradeoff, as is
often the case in early trade studies.
That's where the "skilled evaluator" comes in. A person with some years of
experience can integrate all those different factors fairly easily.
> > Aha... your idea has been anticipated! Several people have done just
> > (using a Beowulf, even, for the optimizing). Randy Haupt did a fair
> > amount
> > of it with wire antennas (and others, I'm sure). There was also
> > at
> > UCLA who designed wireless antennas using just what you describe
> > and removing small patches of conductive surface). They then
> > the antennas and tested them.
>Yes, there are a number of extant solutions using stochastic
>optimization in the automotive and aerospace manufacturers among others
>for these very purposes. Clusters running in throughput mode are a
>really good engine for this work.
>David N. Lombard
>My comments represent my opinions, not those of Intel Corporation.
James Lux, P.E.
Spacecraft Radio Frequency Subsystems Group
Flight Communications Systems Section
Jet Propulsion Laboratory, Mail Stop 161-213
4800 Oak Grove Drive
Pasadena CA 91109
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