Re: Particle Swarm Optimization

Albert van der Horst <albert@[EMAIL PROTECTED]
> writes Re: Particle Swarm
Optimization
[..]

> Was your ampliphier a discrete problem?

No. But it has multiple solutions at (sub)multiples of the 
switching frequency, and near a solution the phase relation
between current and voltage is extremely im****tant (ns resolution
required). Furthermore, I needed to minimize a vector function, 
so it was necessary to 'play' with the weights of the 
vector-to-scalar conversion.

[..]

> 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.

How did you know it was already optimal? (I assume you not really
meant to say that was a given). Even if your client would not 
implement the final program, they should've been interested to 
know by how much their current software was off the optimum.

> 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.

For the amplifier problem, a single algorithmic step costs a full
eight HF-cycle simulation of the entire circuit. I didn't do the 
simulation in SPICE, but wrote the circuit equations in Matlab 
so that the amplifier became a function of its component values.
If I need to take it further (the project is by far not finished 
yet), I'll do only the inner steps with SPICE (sort of a 
space-mapping approach).

-marcel