SCF CALCULATIONS ON MIMD TYPE PARALLEL COMPUTERS

One of the key methods in quantum chemistry, the Hartree-Fock SCF meth od, is performing poorly on typical vector supercomputers. A significa nt acceleration of calculations of this type requires the development and implementation of a parallel SCF algorithm. In this paper various parallelization strategies are discussed comparing local and global co mmunication management as well as sequential and distributed Fock-matr ix updates. Programs based on these algorithms are bench marked on tra nsputer networks and two IBM MIMD prototypes. The portability of the c ode is demonstrated with the portation of the initial Helios version t o other operating systems like Parallel VM/SP and PARIX. Based on the PVM libraries, a platform-independent version has been developed for h eterogeneous workstation clusters as well as for massively parallel co mputers.