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Record Details

Record 78 of 97443
Massively parallel computation of RCS with finite elements
Author and Affiliation:
Parker, Jay(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Abstract: One of the promising combinations of finite element approaches for scattering problems uses Whitney edge elements, spherical vector wave-absorbing boundary conditions, and bi-conjugate gradient solution for the frequency-domain near field. Each of these approaches may be criticized. Low-order elements require high mesh density, but also result in fast, reliable iterative convergence. Spherical wave-absorbing boundary conditions require additional space to be meshed beyond the most minimal near-space region, but result in fully sparse, symmetric matrices which keep storage and solution times low. Iterative solution is somewhat unpredictable and unfriendly to multiple right-hand sides, yet we find it to be uniformly fast on large problems to date, given the other two approaches. Implementation of these approaches on a distributed memory, message passing machine yields huge dividends, as full scalability to the largest machines appears assured and iterative solution times are well-behaved for large problems. We present times and solutions for computed RCS for a conducting cube and composite permeability/conducting sphere on the Intel ipsc860 with up to 16 processors solving over 200,000 unknowns. We estimate problems of approximately 10 million unknowns, encompassing 1000 cubic wavelengths, may be attempted on a currently available 512 processor machine, but would be exceedingly tedious to prepare. The most severe bottlenecks are due to the slow rate of mesh generation on non-parallel machines and the large transfer time from such a machine to the parallel processor. One solution, in progress, is to create and then distribute a coarse mesh among the processors, followed by systematic refinement within each processor. Elimination of redundant node definitions at the mesh-partition surfaces, snap-to-surface post processing of the resulting mesh for good modelling of curved surfaces, and load-balancing redistribution of new elements after the refinement are auxiliary steps expected to result in a robust low i/o system for very large finite element problems.
Publication Date: Jan 01, 1993
Document ID:
19940015964
(Acquired Dec 28, 1995)
Accession Number: 94N20437
Subject Category: COMMUNICATIONS AND RADAR
Coverage: Abstract Only
Document Type: Conference Paper
Publication Information: gress In Electromagnetics Research Symposium (PIERS); p 605
Publisher Information: United States
Financial Sponsor: NASA; United States
Organization Source: Jet Propulsion Lab., California Inst. of Tech.; Pasadena, CA, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: FINITE ELEMENT METHOD; GRID GENERATION (MATHEMATICS); MASSIVELY PARALLEL PROCESSORS; NEAR FIELDS; PARALLEL PROCESSING (COMPUTERS); RADAR CROSS SECTIONS; RADAR SCATTERING; BOUNDARY CONDITIONS; CONVERGENCE; ITERATIVE SOLUTION; MATRICES (MATHEMATICS)
Imprint And Other Notes: In its Progress In Electromagnetics Research Symposium (PIERS) p 605 (SEE N94-20403 05-32)
Availability Source: Other Sources
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