NEC-LIST: Re: Compiling NEC for a Large Number of Segments

Mr. Carter and all;

I have had for some time worked on getting the maximum number of
segments out of NEC-4 built on a Unix-like system. The best that I have
gotten is 30000 segments. Beyond that, I get compiler exceptions of the
same general sort as you got. Earlier discussions on the board alluded
to the need to change certain parts of the Fortran code to accomidate
larger segment definition. This setup was compiled and runs on MacOS X
10.4.6 on a klunky old 32-bit, 768MHz, QuickSilver G4 - slow, but it got
results.

All attempts to run very large models even for very good commercial
NEC-4 packages resulted in failures of Windows memory management. The
IT manager here is setting us up with a Linux PC (probably Xandros
64-bit when it is released). This will allow compiling NEC-4 Unix
source using g77 which is a f2c-like translater (I think) that then
calls the gcc compiler.

In case you want to try the Linux route, the reference that enabled me
to compile was posted on this list by John B. Wood 03/04/04:

> Hello. I ran a thread on this subject a while back. NEC 4.1 can be
> somewhat optimized to run on a Linux box by compiling with g77 as
> follows:
>
> g77 nec41.f -O3 -fno-automatic
>
> where nec41.f is the NEC 4.1 f77 source code file. The default
> executable filename will be nec41.o. The above gave me results
> consistent with those I had obained on an old HPUX workstation. You
> might also try
>
> g77 -O3 -fno-emulate-complex -funroll-loops nec41.f
>
> This version of the compile was published in the Nov. '98 ACES
> newletter but I never could get the executable to run reliably on the
> laptop I was using (Panasonic Toughbook CF-27). Sincerely,
>

I have used both of the above proceedures to compile NEC-4 on Mac OS X.
and have gotten good results for double-precision models of about 16000
wire segments. As I remember, someone mentioned a complication with
very large models using wire segmants that connect to patches.

Hope this helps,

Darryl Holder

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