title: Improvement of parallelization performance of GAMESS: global sum and (semi-)direct integral calculation in multireference perturbation calculation.
abstract: Performance benchmark tests of the multireference perturbation theory (MRPT2) calculation in the GAMESS suite of programs have been performed on a 128-node PC cluster system. The benchmark results point to two kinds of problems with GAMESS: network delay and slow access to disk files. To overcome these bottlenecks, we employ (semi-)direct atomic orbital integral calculations and a new algorithm for the "global sum" operation. These modifications produce remarkable performance improvements, especially in the 128-node PC cluster system, which was almost twice as fast in our version as in the original version. The modification of "global sum" also improved the performance of other types of molecular orbital calculations in GAMESS, such as density functional theory.
authors.affiliation: Department of Material Science, College of Integrated Arts and Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Umeda
authors.forename: Shiro
authors.initials: S
authors.lastname: Koseki
authors.forename: Umpei
authors.initials: U
authors.lastname: Nagashima