Highly parallel SCF calculation: the SYSMO Program

This article presents a parallel implementation of the Linear Combination ofAtomic Orbitals - Self Consistent Field (LCAO-SCF) algorithm, based on the Parallel Virtual Machine (PVM) environment and the System Modena (SYSMO) suite of computer programs, explicitly oriented for highly parallel computing. Parallelism is achieved at the Single Program Multiple Data (SPMD) level, dividing the calculation of two electron integrals between processes; special attention has been given to load balancing and minimizing communications between processes. The algorithm is suitable for both conventional and direct SCF approaches. Tests give us results that show the high scalability of the algorithm having efficiency 0.97.