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Free keywords:
Physics, Computational Physics, physics.comp-ph, Condensed Matter, Materials Science, cond-mat.mtrl-sci
Abstract:
We present a massive-parallel implementation of the resolution-of-identity
(RI) coupled-cluster approach that includes single, double and perturbatively
triple excitations, namely RI-CCSD(T), in the FHI-aims package for molecular
systems. A domain-based distributed-memory algorithm in the MPI/OpenMP hybrid
framework has been designed to effectively utilize the memory bandwidth and
significantly minimize the interconnect communication, particularly for the
tensor contraction in the evaluation of the particle-particle ladder term. Our
implementation features a rigorous avoidance of the on-the-fly disk storage and
an excellent strong scaling up to 10,000 and more cores. Taking a set of
molecules with different sizes, we demonstrate that the parallel performance of
our CCSD(T) code is competitive with the CC implementations in state-of-the-art
high-performance computing (HPC) computational chemistry packages. We also
demonstrate that the numerical error due to the use of RI approximation in our
RI-CCSD(T) is negligibly small. Together with the correlation-consistent
numeric atom-centered orbital (NAO) basis sets, NAO-VCC-nZ, the method is
applied to produce accurate theoretical reference data for 22 bio-oriented weak
interactions (S22), 11 conformational energies of gaseous cysteine conformers
(CYCONF), and 32 isomerization energies (ISO32).
