Performance Analysis of Vectorized Nuclear Codes On a Facom Vp-100 At the Japan Atomic Energy Research Institute

We have evaluated the performance of vectorized nuclear codes used at the Japan Atomic Energy Institute. Forty nu clear codes were restructured for vectori zation, with an average vectorization of 83%. The vector to scalar ratio for modi fied code performance is about 5. Vectori zation improved performance in most cases, but certain codes, including LOCA and Monte Carlo codes, required consid erable effort to vectorize, without high performance gains. We discuss the bar riers to achieving high performance, and the need to consider applications charac teristics when evaluating system performance.