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Parallelization of four‐component calculations. II. Symmetry‐driven parallelization of the 4‐Spinor CCSD algorithm
Author(s) -
Pernpointner Markus,
Visscher Lucas
Publication year - 2003
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.10215
Subject(s) - spinor , coupled cluster , component (thermodynamics) , computer science , computation , node (physics) , dirac (video compression format) , series (stratigraphy) , algorithm , parallel computing , mathematics , physics , quantum mechanics , mathematical physics , molecule , neutrino , paleontology , biology
Given the importance of the Coupled‐cluster (CC) method as an efficient and accurate way to take electron correlation into account, we extend the parallelization technique in the second part of this series also to the 4‐Spinor CCSD algorithm implemented in the Dirac–Fock packages DIRAC and MOLFDIR. The present implementation is based on the availability of the transformed molecular two‐electron integrals on an external storage medium. The linearity of the CC equations in these two‐electron integrals is used in a parallelization strategy that is based on distribution of the two largest integral classes that carry three or four virtual spinor indices. The corresponding partial contributions to the T 1 and T 2 amplitudes are calculated on each node and added using Message Passing Interface (MPI) library calls. Although we did not employ a master/slave principle, one specific node was assigned to also perform the remaining serial parts of the algorithm. In the critical sections considerable savings in storage requirements and computer time could be achieved, and this allows for computations on larger systems in the framework of four‐component theory. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 754–759, 2003