On the Use of Diffusion Synthetic Acceleration in Parallel 3D Neutral Particle Transport Calculations

On the Use of Diffusion Synthetic Acceleration in Parallel 3D Neutral Particle Transport Calculations

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Published: 1998

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The linear Boltzmann transport equation (BTE) is an integro-differential equation arising in deterministic models of neutral and charged particle transport. In slab (one-dimensional Cartesian) geometry and certain higher-dimensional cases, Diffusion Synthetic Acceleration (DSA) is known to be an effective algorithm for the iterative solution of the discretized BTE. Fourier and asymptotic analyses have been applied to various idealizations (e.g., problems on infinite domains with constant coefficients) to obtain sharp bounds on the convergence rate of DSA in such cases. While DSA has been shown to be a highly effective acceleration (or preconditioning) technique in one-dimensional problems, it has been observed to be less effective in higher dimensions. This is due in part to the expense of solving the related diffusion linear system. We investigate here the effectiveness of a parallel semicoarsening multigrid (SMG) solution approach to DSA preconditioning in several three dimensional problems. In particular, we consider the algorithmic and implementation scalability of a parallel SMG-DSA preconditioner on several types of test problems.


Energy Research Abstracts

Energy Research Abstracts

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Publisher:

Published: 1986

Total Pages: 562

ISBN-13:

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Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.


Recently Developed Methods in Neutral-particle Transport Calculations

Recently Developed Methods in Neutral-particle Transport Calculations

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Published: 1982

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It has become increasingly apparent that successful, general methods for the solution of the neutral particle transport equation involve a close connection between the spatial-discretization method used and the source-acceleration method chosen. The first form of the transport equation, angular discretization which is discrete ordinates is considered as well as spatial discretization based upon a mesh arrangement. Characteristic methods are considered briefly in the context of future, desirable developments. The ideal spatial-discretization method is described as having the following attributes: (1) positive-positive boundary data yields a positive angular flux within the mesh including its boundaries; (2) satisfies the particle balance equation over the mesh, that is, the method is conservative; (3) possesses the diffusion limit independent of spatial mesh size, that is, for a linearly isotropic flux assumption, the transport differencing reduces to a suitable diffusion equation differencing; (4) the method is unconditionally acceleratable, i.e., for each mesh size, the method is unconditionally convergent with a source iteration acceleration. It is doubtful that a single method possesses all these attributes for a general problem. Some commonly used methods are outlined and their computational performance and usefulness are compared; recommendations for future development are detailed, which include practical computational considerations.


Handbook of Nuclear Engineering

Handbook of Nuclear Engineering

Author: Dan Gabriel Cacuci

Publisher: Springer Science & Business Media

Published: 2010-09-14

Total Pages: 3701

ISBN-13: 0387981306

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This is an authoritative compilation of information regarding methods and data used in all phases of nuclear engineering. Addressing nuclear engineers and scientists at all levels, this book provides a condensed reference on nuclear engineering since 1958.


Numerical Astrophysics

Numerical Astrophysics

Author: Shoken M. Miyama

Publisher: Springer Science & Business Media

Published: 1999-03-31

Total Pages: 470

ISBN-13: 9780792355663

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This book contains all the oral and poster sessions presented at the `Numerical Astrophysics 1998' symposium held in Tokyo on March 10-13, 1998. It covers a wide variety of research fields, from the large-scale structure of the Universe to planetary systems. Astrophysics employing all kinds of supercomputers, such as massive-parallel computers, parallel vector machines, and special-purpose computers, are included. Recent progress in numerical methods, remote data analysis, and special-purpose computers are also reviewed. This book is suitable for researchers and graduate students in astronomy/astrophysics, who want an overview of the present research fronts based on supercomputing.