OUT-OF-CORE SOLVER FOR LARGE, MULTIZONE BOUNDARY-ELEMENT MATRICES

In this paper an out-of-core solver is developed for a three-dimensional elastostatic boundary element program. This program includes multi-regions which enables a large model to be divided into a number of homogeneous sub-models, each with their own material properties. The system matrix produced by multi-regions is sparse, blocked and unsymmetric in character and so reduces disc space and solution time. The solver presented in this paper utilizes efficiently the structure of this matrix by holding only non-zero parts of this matrix in a sequential, unformatted direct access file, reading in as much of the file as possible into the working space, performing Gauss elimination, then writing part of the matrix back to file. The maximum utilization of working space is particularly important on vector machines as vector activity is maximized whilst record read/write is minimized. The effect of multi-regions on CPU is demonstrated on both the CONVEX and GRAY machines.