Large Scale Electromagnetic Analysis Using Unstructured Grids

Tom Cwik, Daniel S. Katz*, Cinzia Zuffada, and Vahraz Jamnejad

Jet Propulsion Laboratory
4800 Oak Grove Drive
California Institute of Technology
Pasadena, California, 91109
(818) 354-4386

*Cray Research Inc.
Suite 1406
222 N. Sepulveda
El Segundo, California, 90245

This paper discusses a software package being developed for the simulation of electromagnetic fields scattered from complex objects. This package uses an unstructured finite element model, and its parallel implementation uses a non-traditional mesh decomposition algorithm. The complete software package is implemented on the Cray T3D massively parallel processor located at the Jet Propulsion Laboratory, using both Cray Adaptive FORTRAN (CRAFT) compiler constructs and message passing. CRAFT is used to simplify portions of the code that operate on irregular data, and optimized message passing is used on portions of the code that operate on regular data and require optimum machine performance. An optimized parallel iterative solver has been developed to solve large sparse systems resulting from the finite element simulation.

For this simulation, a tradeoff exists between problem decomposition and problem solution. The simulation software developed includes a simple decomposition, and a reasonably optimized solution algorithm to create excellent load balance and minimize communication overhead. This software structure also minimizes the time and effort needed in parallelization. Results of the complete simulation are presented and analyzed for varying size problems. Ideas for additional optimization will also be discussed.