Re: Particle Swarm Optimization

In article <22823313213559@[EMAIL PROTECTED]
>, Marcel Hendrix <mhx@[EMAIL PROTECTED]
>
wrote:
>anton@[EMAIL PROTECTED]
 (Anton Ertl) writes Re: Particle Swarm
Optimization
>> mhx@[EMAIL PROTECTED]
 (Marcel Hendrix) writes:
>>> Triggered by a (German) C't article, last week I experimented a bit
>>> with Particle Swarm Optimization.
>> ...
>>> Unfortunately, I found the results quite unconvincing.
>[..]
>> Yes.  Maybe I missed something, but the particle swarm stuff seems to
>> be similar to ant algorithms to me; and that fails to convince me, too
>> (but maybe I miss the point of that, too): We know the best path yet
>> after the first ant walks it, no need to simulate multiple ants
>> walking the same path.  Such algorithms may have a place if you have
>> massive parallelism, and very limited communication bandwidth compared
>> to computation, but not in settings that most of us use.
>
>Well, ant algorithms can solve 'discrete' problems (without
>derivatives) which is useful. AFAIK, particle swarms can't
>handle such discrete problems, and are very bad at accurately
>finding derivatives. Apparently the algorithm is so deeply
>buried in C++ that even C't editors can't find it. Or maybe
>they were only looking at the graphics :-)

Was your ampliphier a discrete problem?

I got interested in simulated annealing for planning problems.
My previous assignment involved a steel milling plant, with many
restrictions on what products can follow what other products, and
complicated rules about using resources and weighting unrelated
aspects.

Given there are about thousand products a week, so the search space
was 1000! to start with, and given that computer assisted planning
already was very near optimal, I gave the customer little hope that a
s.a. solution could better this, so the project was cancelled.
But this left me wondering how far s.a. could have got with this
problem. Evaluating a planning involves running a simulated
factory over it, which is much more costly than a step evaluation
in a typical travelling salesman problem.

>
>-marcel
>

Groetjes Albert

--
-- 
Albert van der Horst, UTRECHT,THE NETHERLANDS
Economic growth -- like all pyramid schemes -- ultimately falters.
albert@[EMAIL PROTECTED]
 &=n http://home.hccnet.nl/a.w.m.van.der.horst