The General Atomic and Molecular Electronic Structure System (GAMESS) [1] code is a quantum chemistry code developed by the Gordon Research Group at the Department of Energy Ames Laboratory and Iowa State University. It is employed in the first-principles modeling of complex molecular systems by using the density functional theory (DFT) [2] method as well as a number of other post Hartree-Fock (HF) methods. Both DFT and time-dependent DFT (TDDFT) [3] are of particular interest to the DoD computational biology, chemistry, and materials science community.

Millions of CPU hours per year are expended by GAMESS calculations on DoD high-performance computing (HPC) systems. Therefore, any reduction in wall-clock time for these calculations represents a significant saving in CPU hours. As part of this work, three areas for improvement were identified: (1) integration-grid replacement, (2) TDDFT parallelization, and (3) profiling and optimization of the DFT & TDDFT. This talk will focus on the profiling and optimization of DFT calculations. These software enhancements are to be made available in the next official release of GAMESS.