HIGHLY PARALLELIZED SPECIAL-PURPOSE COMPUTER, GRAPE-3

We have developed a highly parallelized special-purpose computer, GRAPE (GRAvity PipE)-3, for gravitational many-body simulations. Its peak computing speed is equivalent to 15 Gflops. The GRAPE-3 system comprises two identical boards connected to a host computer (workstation) through the VME bus. Each board has 24 custom LSI chips (GRAPE chips) which calculate gravitational forces in parallel. The calculation of the gravitational forces is easily parallelized, since the forces on different particles can be calculated independently. One GRAPE chip running at a 10 MHz clock has a computing speed equivalent to 0.3 Gflops; the GRAPE-3 system with 48 GRAPE chips thus achieves a peak speed of 15 Gflops. The sustained speed of the GRAPE-3 system reached 10 Gflops-equivalent.