Vectorization of MORSE-DD code

We have vectorized the multi-group Monte Carlo code MORSE-DD. The Monte Carlo method is very powerful to simulate the motion of particles. However the Monte Carlo codes spend much calculation time, it is required to accelerate the codes by using vector processing. It was known that vectorization of the Monte Carlo codes for treating with the neutron transport problem is very difficult, because each neutron has a different motion and there are many paths in a Monte Carlo step. The Monte Carlo step of MORSE-DD code is completely rewritten by using event bank method. As the result, we have obtained speedup 1.55 times on FACOM VP-100 compared with the original code in scalar mode for problem to analyze neutron behaviour in FNS (Fusion Neutron Source). In this report, the techniques employed for vectorization and the essential problems which prevent from the efficient use of vector processor are described. (author)