## Efficient Parallel All-Electron Four-Component Dirac–Kohn–Sham Program Using a Distributed Matrix Approach II

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posted on 10.12.2013, 00:00 by Loriano Storchi, Sergio Rampino, Leonardo Belpassi, Francesco Tarantelli, Harry
M. QuineyWe propose a new complete memory-distributed
algorithm, which significantly
improves the parallel implementation of the all-electron four-component
Dirac–Kohn–Sham (DKS) module of BERTHA (

*J. Chem. Theory Comput.***2010**,*6*, 384). We devised an original procedure for mapping the DKS matrix between an efficient integral-driven distribution, guided by the structure of specific G-spinor basis sets and by density fitting algorithms, and the two-dimensional block-cyclic distribution scheme required by the ScaLAPACK library employed for the linear algebra operations. This implementation, because of the efficiency in the memory distribution, represents a leap forward in the applicability of the DKS procedure to arbitrarily large molecular systems and its porting on last-generation massively parallel systems. The performance of the code is illustrated by some test calculations on several gold clusters of increasing size. The DKS self-consistent procedure has been explicitly converged for two representative clusters, namely Au_{20}and Au_{34}, for which the density of electronic states is reported and discussed. The largest gold cluster uses more than 39k basis functions and DKS matrices of the order of 23 GB.