MOLECULAR-DYNAMICS ON APE100

We have studied portability, efficiency and accuracy of a standard Mol ecular Dynamics simulation on the SIMD parallel computer APE100. Compu ting speed performance and physical system size range have been analyz ed and compared with those of a conventional computer. Short range and long range potentials have been considered, and the comparative advan tage of different simulation approaches has been assessed. For long ra nge potentials, APE turns out to be faster than a conventional compute r; large systems can be conveniently simulated using either the clonin g approach (up to similar to 10(5) particles) or a domain decompositio n with the systolic method. In the case of short range potentials and systems with diffusion (like a liquid), APE is convenient only when us ing a large number of processors. In a special case (a crystal without diffusion), a specific domain decomposition technique with frames mak es APE advantageous for intermediate and large systems. Using the latt er technique we have studied in detail the effect of different numeric al error sources, and compared the accuracy of APE with that of a conv entional computer.