Vector coding the finite-volume procedure for the CYBER 205 (Q1067914)

The paper reviews a method for the large-scale numerical simulation of fluid flow and discusses fundamental principles of vector programming in FORTRAN in order to set the stage for the main topic, the vector coding and execution of the finite-volume procedure on the CYBER 205. With the proper structure given to the data by the grid transformation each coordinate direction can be differenced throughout the entire grid in one vector operation. Boundary conditions must be interleaved which tends to inhibit the concurrency of the overall scheme, but a strategy of no data motion together with only inner-loop vectorization is judged to be the best compromise. The computed example of transonic vortex flow separating from the sharp leading edge of a delta wing demonstrates the processing performance of the procedure. Vectors over 40.000 elements long are obtained, and a rate of over 125 megaflops sustained over the entire computation indicates the high degree of vectorization achieved.