The International Conference for High Performance Computing, Networking, Storage and Analysis
RHF SCF Parallelization in GAMESS by Using MPI and OpenMP.
Authors: Yuri Alexeev (Argonne National Laboratory), Graham Fletcher (Argonne National Laboratory), Vitali Morozov (Argonne National Laboratory)
Abstract: In the exascale era, only carefully tuned applications are expected to scale to millions of cores. For quantum chemistry, one of the practical solutions to achieve such scalability is to employ new highly parallel methods which use both MPI and OpenMP. In this work, we optimized code and developed a thread-safe Rys quadrature integral code with parallelized Self Consistent Field (SCF) method using OpenMP in quantum chemistry package GAMESS. We implemented and benchmarked three different hybrid MPI/OpenMP algorithms, and discussed their advantages and disadvantages. The most efficient MPI/OpenMP algorithm was benchmarked against an MPI-only implementation on Mira, the ALCF’s IBM Blue Gene/Q supercomputer, and was shown to be consistently faster by a factor of two.