Re: NEC parallel

Gerry van Dooren asked:
 
> I wondered whether there are people out there that have ported the
NEC (V2)
> code to a parallel platform? If yes, any information is appreciated....
 
NEC2 parallel: Overview of efforts at Dept. Elec. Eng. at the
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University of the Witwatersrand, South Africa.
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A number of years ago Derek Nitch implemented a parallel version of
NEC2 using a mixture of FORTRAN and OCCAM code which he implemented
and tested on INMOS T800 transputers. This effort was reported on in:

DC Nitch and APC Fourie, 'Adapting NEC to run in parlallel on a
network of transputers'. In SAIEE Third Joint Symposium on Antennas
and Propagation and Microwave Theory and Techniques, pages 31-38.
Somerset West, August 1990. An M.Sc. dissertation on this topic was
also submitted by Derek Nitch in June 1990 at this university.

Parallel efficiencies in the order of 90% and higher were obtained
for both matrix filling and factoring.

We found the FORTRAN code difficult to generalize to different
parallel platforms and NEC2 theory was redesigned using the Object
Oriented Paradigm and coded using the C++ language. This produced a
program, which we call SuperNEC, which can be ported to different
platforms with ease and in general provided a program very suitable
to modifications. Some of this work is reported on in:

DC Nitch and APC Fourie: 'A redesign of NEC2 using the object
oriented paradigm' in APS International Symposium, Seattle, USA, pp
1150-1153, 1994.

as well as a Ph. D. thesis containing all the detail:

DC Nitch 'A serial and parallel design of NEC2 to demonstrate the
advantages of the objecto oriented paradigm in comparision with the
procedural paradigm'. PhD thesis, University of the Witwatersrand,
Johannesburg, December 1992.

To illustrate one of the benefits of the object oriented SuperNEC
program it was once again modified for parallel execution on T800's
in a period of two weeks as opposed to the 6 months required for the
previous FORTRAN version (excluding all the learning curves i.e.
referring to coding time only). This was reported on in

DC Nitch and APC Fourie, 'Parallel implementation of NEC'. Applied
Computational Electromagnetics Society (ACES) Journal, 9(1) p51-57,
March 1994 as well as the PhD thesis cited above.

Some iterative solution techniques and other modifications
have been added to the SuperNEC implementation, some of these
reported on in:

APC Fourie, and DC Nitch, 'A fast sparse interative method (SIM) for
method of moments' as well as 'Comparing the sparse iterative method
with the banded Jacobi and conjugate gradient techniques.' Both papers
presented at APS Symposium in Seattle, USA, 1994. pp1146-1149 and pp
1181-1184 respectively.

Recently the SuperNEC program has been adapted to run in parallel on
workstations connected with a TCPIP LAN using a public domain program
for inter machine communication called PVM (Parallel Virtual
Machine). This parallel implementation is the most attractive to date
with the following features:

- Distribution of computational effort as well as memory making use
of workstations available on a local area network.

- Different machines can be used (we have used networks with a
mixture of IBM R6000's and SUN Sparc 10's and 2's). (Load balancing
is possible, but not yet implemented)

- All important numerical components are in parallel in terms of
memory as well as execution (filling, iterative as well as LU
solving, near field and radiation pattern calculations, symmetry
computations etc).

We believe the PVM approach to be very attractive, since it is a move
away from dedicated parallel architectures and allows the user to
make use of available, general purpose workstations on the LAN.

Regards
Andre Fourie
e-mail: fourie_at_odie.ee.wits.ac.za
Tel: intl + 27 11 716 5386
Fax: intl + 27 11 339 4610
Address: Dr. APC Fourie, Dept Elec Eng, PO WITS, 2050, South Africa
Received on Tue Jul 25 1995 - 23:10:00 EDT