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Manuscript Title: LOCFES: a program for automatic determination of the order of spatial approximations in one-dimensional particle transport.
Authors: P. Nelson, D.S. Ek
Program title: LOCFES
Catalogue identifier: ACJP_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 74(1993)91
Programming language: Fortran.
Computer: VAX 9000-210V.
Operating system: VMS VERSION 5.4-1A.
RAM: 86K words
Word size: 32
Keywords: Reactor systems, Particle transport, Neutron transport, Radiative transfer, Discrete ordinates, Source iteration, (closed) linear one Cell functional methods.
Classification: 21.2, 22.

Other versions:
Cat Id Title Reference
ACVD_v1_0 LOCFES-B CPC 82(1994)265

Nature of problem:
Monoenergetic and azimuthally symmetric neutron transport in one- dimensional plane-parallel geometry.

Solution method:
Source iteration applied to a discrete approximation defined by the discrete-ordinates approximation for the angular variable, with a quadrature rule specified by input, and an arbitrary closed linear one- cell approximation for the spatial variable, as defined by a user- supplied modular subroutine.

The current version is limited to 8 angular (polar direction cosine) quadrature points, that must be symmetric about the origin. It also is limited to 3 zones, a maximum of 4096 spatial cells per zone, and closed linear one-cell spatial approximations having at most four basic linear functionals. These dimensional limitations may be changed by resetting appropriate parameters.

Unusual features:
The code is designed to facilitate testing and comparsion of different spatial approximations in neutron transport. Accordingly, it permits automatic determination of both the rate of convergence of the source iteration, and of the order of accuracy of a particular spatial approximation, the latter through successive applications of source iteration for a sequence of (automatically) refined meshes.

Running time:
Approximately of the form C1 ncells nmu(1+C2 nblf) per ray-tracing sweep, where the Ci are "constants" that depend on both the computational platform and the particular closed linear one-cell spatial approximation being employed, ncells is the (total, over all zones) number of spatial cells in the mesh, nmu is the number of quadrature points, and nblf is the number of basic linear functionals in the CLOF being employed. For a VAX 9000 and the diamond-difference and linear- characteristic methods, C1 is on the order of several (5 to 10) mu seconds, and C2 is of the order of unity.