Premium
Distributed data parallel coupled‐cluster algorithm: Application to the 2‐hydroxypyridine/2‐pyridone tautomerism
Author(s) -
Rendell Alistair P.,
Guest Martyn F.,
Kendall Rick A.
Publication year - 1993
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.540141204
Subject(s) - tautomer , coupled cluster , cluster (spacecraft) , excitation , chemistry , maxima and minima , state (computer science) , computer science , algorithm , mathematics , physics , molecule , quantum mechanics , stereochemistry , mathematical analysis , organic chemistry , programming language
The recently developed parallel coupled‐cluster algorithm of Rendell, Lee, and Lindh [ Chem. Phys. Lett. , 194 , 84 (1992)] is extended to allow four‐indexed quantities containing one or two indices in the virtual orbital space to be stored across the global memory of distributed‐memory parallel processors. Quantities such as the double‐excitation amplitudes can now be distributed over multiple nodes, with blocks of data retrieved from remote nodes by the use of interrupt handlers. As an application of the new code, we have investigated the potential energy surface of the 2‐hydroxypyridine/2‐pyridone tautomers. Using large basis sets, the structure of each tautomer and the transition state connecting the two minima has been determined at the SCF level. The relative energy difference and the activation energy were then redetermined using the MP2, CCSD, and CCSD(T) methods. All calculations have been performed on Intel distributed‐memory supercomputers. The largest coupled‐cluster calculations contained over 2 million double‐excitation amplitudes. © John Wiley & Sons, Inc.