4nec2 wrote:
On 16 jun, 21:45, art wrote:


Do you know of a program that for optimisation can work with all
dimensions being variable AT THE SAME TIME?


Yes, maybe. If I am correct you do have some AO experience. 4nec2 does
contain an optimiser based on the same principles, however it's not
Mininec based as OA was, but Nec2 based (or Nec4 based if you own a
Nec4 license).
You can directly read-in your *.ao files into 4nec2, they will be
automatically converted. Complicated ao files may need some minor
manual changes afterwards.

You can include as much variables as you like in your antenna model
and for each run, you can select the variables to optimise from the
list. When the run has completed and the selected quality of your
model has been optimized as good as possible, you can (partly)
deselect previous variables and select another set of variabels and
continue optimization based on the outcome of previous run.

Furthermore it also contains a GA (genetic algorithms) based optimizer
similar to the one included in the commercial SuperNec package.

When optimizing multiple variables at the same time, this type of
optimizer is prefered. It also avoids the model of being trapped in
local maxima. The drawback of this is the increase of optimization
time needed.

However be aware, it needs some 'learning curve'.
There seem to be two distinct groups of people, those who adore it and
those who think it's much to complicated. It seems not possible to
'sit' anywhere between those both extremes.


I think this is true of all optimizers..
The more complex the thing being optimized, the more difficult it is to
have a generic interface that provides a way for the user to tell the
optimizer what the constraints and desires are. In the limit, you wind
up writing a program to implement the constraints, and another program
to implement the evaluation function, and yet another program to take
the optimized variables and turn it into a model which the modeling
engine can run.