Premium
Parallelization of a multiconfigurational perturbation theory
Author(s) -
Vancoillie Steven,
Delcey Mickaël G.,
Lindh Roland,
Vysotskiy Victor,
Malmqvist PerÅke,
Veryazov Valera
Publication year - 2013
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.23342
Subject(s) - infiniband , computer science , scalability , parallel computing , scaling , supercomputer , memory bandwidth , shared memory , bandwidth (computing) , distributed memory , interconnection , programming paradigm , partitioned global address space , computational science , architecture , latency (audio) , distributed computing , operating system , mathematics , art , computer network , geometry , visual arts , telecommunications , programming language
In this work, we present a parallel approach to complete and restricted active space second‐order perturbation theory, (CASPT2/RASPT2). We also make an assessment of the performance characteristics of its particular implementation in the Molcas quantum chemistry programming package. Parallel scaling is limited by memory and I/O bandwidth instead of available cores. Significant time savings for calculations on large and complex systems can be achieved by increasing the number of processes on a single machine, as long as memory bandwidth allows, or by using multiple nodes with a fast, low‐latency interconnect. We found that parallel efficiency drops below 50% when using 8–16 cores on the shared‐memory architecture, or 16–32 nodes on the distributed‐memory architecture, depending on the calculation. This limits the scalability of the implementation to a moderate amount of processes. Nonetheless, calculations that took more than 3 days on a serial machine could be performed in less than 5 h on an InfiniBand cluster, where the individual nodes were not even capable of running the calculation because of memory and I/O requirements. This ensures the continuing study of larger molecular systems by means of CASPT2/RASPT2 through the use of the aggregated computational resources offered by distributed computing systems. © 2013 Wiley Periodicals, Inc.