Chaotic, Single-Pass Inner-Iteration Scheme for the Discrete Ordinate Method S(sub n)

摘要

A chaotic, single-pass inner-iteration scheme for the deterministic transport algorithm S/sub n/ is presented. The single-pass scheme is a slight modification to the standard iterative S/sub n/ method. In the standard scheme, an energy group may make multiple sweeps through the inner iteration loop before satisfying a convergence criterion that controls the group's termination of the iteration loop. In the single-pass scheme, only a single inner-iteration pass is allowed for each energy group. This scheme is executed both sequentially and in parallel. The parallel implementation executes without synchronizing the updates of the outer flux, whose iterates are passed between higher and lower energy groups during the inner iteration. This unsynchronized access to the outer flux represents the chaotic nature of this algorithm. The performance of the single-pass scheme is presented in terms of execution times and total number of inner-iteration counts required for the solution of the particular source calculation. The paper also examines the effects due to different problem (input) specifications. 7 refs., 12 figs. (ERA citation 14:023689)