A Parallel Computing Method for the CoupledCluster Singles and Doubles
Abstract
In this paper, we present a parallel computing method for the coupledcluster singles and doubles (CCSD) in periodic systems. The CCSD in periodic systems solves simultaneous equations for singleexcitation and doubleexcitation amplitudes. In the simultaneous equations for doubleexcitation amplitudes, each equations are characterized by four spin orbitals and three independent momentums of electrons. One of key ideas of our method is to use process numbers in parallel computing to identify two indices which represent momentum of an electron. When momentum of an electron takes $N_{\bm{k}}$ values, $N_{\bm{k}}^2$ processes are prepared in our method. Such parallel distribution processing and way of distribution of known quantities in the simultaneous equations reduces orders of computational cost and required memory scales by $N_{\bm{k}}^2$ compared with a sequential method. In implementation of out method, communication between processes in parallel computing appears in the outmost loop in a nested loop but does not appear inner nested loop.
 Publication:

arXiv eprints
 Pub Date:
 November 2019
 arXiv:
 arXiv:1911.00242
 Bibcode:
 2019arXiv191100242Y
 Keywords:

 Condensed Matter  Strongly Correlated Electrons;
 Condensed Matter  Materials Science;
 Physics  Computational Physics