Re: design of analog circuits using genetic algorithm

On Tue, 11 Mar 2008 12:05:24 -0700, "Joel Koltner"
<zapwireDASHgroups@xxxxxxxxx> wrote:

"John Larkin" <jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:0cldt3hl9rrp0llh7hp7l79lk58jibvna9@xxxxxxxxxx
People, mostly academics, keep trying this. As far as I know, it
doesn't work. Understanding electronics is still better than random
fiddling; the solution spaces, first for a topology and then for
values, is just too big.

I believe you were the one telling us you're personally much more than just a
giant genetic algorithm yourself though, right, John? :-)

Somehow a few trillion neurons work better than a few thousand lines
of code. Maybe some day computers will be better than people for
circuit design, like they are now for chess. But chess has rules.


I agree with you, although I will point out for the benefit of the O.P. that
using optimizers (genetic algorithms or more traditional ones) to *tweak*
component values once you have a decent toplogy and reasonably sane starting
values is quite common and successful.

Have you done genetic optimization of circuit values? I guess you'd
first have to come up with a scoring system that defines "best" (like,
for a voltage regulator, something that includes line reg, load reg,
tc, transient response, standard value parts, cost? Then wrap around
that a simulator, then wrap around that the random value diddler and
genetic selection stuff. I can see that diverging fast. Or rather,
diverging slow. It's easy to get lost in a 17-dimensional space.

Even intelligent diddling and simulation, for something simple like a
filter, can easily become a horror.

I sometines do brute-force numerical searches for things like crystal
frequencies and divisors that satisfy some number of requirements.
That's not so much genetic as just trying a bazillion possible values
in some nested FOR loops.

John


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