Monte Carlo simulation of the Ising model and random number generation on the vector processor

The Monte Carlo simulation of the Ising model on the vector processor is discussed with particular attention given to the development of the vectorizable algorithm and the implementation, tuning, and tests necessary for the large-scale computations. The machine is the HITAC S820/80. The maximum simulation speed is 0.93×10⁹ spins per second for the ferromagnetic Ising models on a simple cubic lattice. The random number generation algorithms are also explained. The present generator can produce 0.62×10⁹ 32-bit random integers per second. The results of randomness tests which use the two-dimensional Ising model are presented