Re: NEC-LIST: segments and/or patches limitation

> I use the 4nec2 program and i see that there is a limitation for the
maximum number of > segments and / or patches that i can use for generate the
geometry (11000).

This maximum is limited by the following (at least for as far as I am
aware):

- Operating system
- Amount of RAM memory.
- 4nec2 program
- Available nec2d(XS) executable(s)

When using windows-95 you can never go beyond appr. 4000 segments
Furthermore the max nr of segments depends on the available amount
of RAM memory (for detailed numbers see 4nec2 help)

Nec2 originally made it possible to do out-of-core calculations,
using some kind of 'virtual memory' (using your hard-disk), thus increasing
the max nr-of-segments, but also dramatically increasing the required
caclulation time due to extensive disk-access.

However I noticed that the traditional DOS based nec2d**.exe executables
(created by Jos Bergevoet) do not support this and limit the
max-nr-of-segments
to the available amount of RAM (minus the amount required by windows itself)
Furthermore the 'biggest' nec2d*.exe executable created is the one for 11000
segments, so even if you would have 1Gb or more memory you could not go
beyond this 11000 segment limit.

Concerning the 'other' nec2dXS*.exe executables (required because nec2d*.exe
executables won't run on windows-XP) it's a somewhat different story.
Because I primarily created the 4nec2 stuff for private use and one of my
interests was optimization of HF antennas using repetitive nec2 runs, I
focussed
on speed and not on large number of segments when selecting a compiler to
create
these nec2dXS executables. This also resulted in nec2dXS executables not
being
able to use virtual (on disk) memory and thus limiting the overall max
segment count
(for the moment) to 5000.

However I also have a set if nec2dXS*.exe files available overhere (created
with another compiler) capable of doing out-of-core calculation. Which makes
it possible to run max-segment-count above the maximum as specified by the
available amount of RAM memory on your system. I must admit, I only did some
tests for some 6000 segments using the 5000 segment executable, but never
tried
to run 11000 segments or even more.

If someone would like to receive the set of 'out-of-core' capable files,
let me know. Depending on requests I could contact Ray Anderson to see
if he is willing to place this set on his nec2 site.

Arie.

p.s. The required amount of memory (max segments) is determined by both the
used number of segments and the used number of patches (the latter times
two,
if I remember correctly).

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