On Sat, 13 Aug 2011 21:07:17 +0200, Helmut Wabnig [email protected] ---
-.dotat wrote:

Am trying to run an optimization on my 3 element yagi which I finally
got into the editor, which was difficult enough.
The optimizer says: no variables selected
but there are none to select.
Empty list field.

I have no experience with 4nec2 to speak of, but what it sounds like
is for an optimizer to work, you must first describe (name as a
variable) what characteristic you would like to vary until the
optimizer achieved an optimal result.

One guess for a three element yagi, I would suspect you would name
three variables, the elements, changing each by by an incremental
length (another variable) at a fixed frequency (another variable) for
maximum gain (another variable) in a particular direction (another
variable). Having said that little at seven variables (some fixed in
value), it is quite a page full of algebra stated in a formulaic way
for the optimizer (However, I fully expect that would be in a table
description, not a literal formula).

Having said even that little, it lends a peek into the number of all
the combinations and permutations of design this leads to. Each
variable taken individually against all the possible others - and then
repeated for the others in turn - leads to what mathematicians call
Combinatorial Explosion (you don't have enough time to wait for the
best solution). This is where constraints are added to the algebra,
and you offer "close enough" as one of them to limit testing.

Nowhere in the helps and getting started they explain that.
I do not want to learn from examples, I rather work from the
basics upwards. Would anyone learn math from a calculus
formula without knowing the arabic numbers first?

Proving the validity of numbers consumed a volume of proofs back when
Whitehead and Russell wrote "Principia Mathematica." It was logically
dead on arrival BEFORE it was published - and yet it was the best
description of simple math known. Calculus was simpler as it is
principally symbol dominated.

73's
Richard Clark, KB7QHC