Title
Improved treatment of exact exchange in Quantum ESPRESSO.
Abstract
We present an algorithm and implementation for the parallel computation of exact exchange in Quantum ESPRESSO (QE) that exhibits greatly improved strong scaling. QE is an open-source software package for electronic structure calculations using plane wave density functional theory, and supports the use of local, semi-local, and hybrid DFT functionals. Wider application of hybrid functionals is desirable for the improved simulation of electronic band energy alignments and thermodynamic properties, but the computational complexity of evaluating the exact exchange potential limits the practical application of hybrid functionals to large systems and requires efficient implementations. We demonstrate that existing implementations of hybrid DFT that utilize a single data structure for both the local and exact exchange regions of the code are significantly limited in the degree of parallelization achievable. We present a band-pair parallelization approach, in which the calculation of exact exchange is parallelized and evaluated independently from the parallelization of the remainder of the calculation, with the wavefunction data being efficiently transformed on-the-fly into a form that is optimal for each part of the calculation. For a 64 water molecule supercell, our new algorithm reduces the overall time to solution by nearly an order of magnitude.
Year
DOI
Venue
2017
10.1016/j.cpc.2017.01.008
Computer Physics Communications
Keywords
Field
DocType
Hybrid DFT,Quantum ESPRESSO,Scalability
Data structure,Mathematical optimization,Quantum ESPRESSO,Electronic structure,Remainder,Hybrid functional,Wave function,Density functional theory,Mathematics,Computational complexity theory
Journal
Volume
ISSN
Citations 
214
0010-4655
2
PageRank 
References 
Authors
0.41
1
7
Name
Order
Citations
PageRank
Taylor Barnes130.76
Thorsten Kurth2578.36
Pierre Carrier330.76
Nathan Wichmann4293.64
David Prendergast541.25
P. R. C. Kent692.15
Jack Deslippe77812.45