GRAPE-2A: a special purpose computer for simulations of many-body systems with arbitrary central force

The authors are developing GRAPE-2A which is a back-end processor to accelerate the simulations of many-body systems such as stellar clusters and systems of molecules. GRAPE-2A calculates forces exerted on one particle from all other particles. The host computer, connected to GRAPE-2A through a VME bus, performs other calculations such as time integration. In the simulation of many-body systems, almost all computation time is consumed in the calculation of forces between particles, i.e. gravitational, Coulomb, and van der Waals forces. GRAPE-2A can calculate the forces with an arbitrary functional form using a hardwired pipeline. The host computer can set the functional form of the force by sending the interpolation data to GRAPE-2A. The computational speed of GRAPE-2A is 300 MFLOPS. Aiming at a speed of 1 TFLOPS, the authors are planning to develop a GRAPE system in which many GRAPE pipelines work in parallel