Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 58: Poster Wednesday: New Methods and Developments, Frontiers of Electronic Structure Theory
O 58.10: Poster
Wednesday, September 7, 2022, 18:00–20:00, P4
Accelerating plane-wave-based ab initio molecular dynamics by optimization of Fast-Fourier transforms for modern HPC architectures — •Christian Ritterhoff, Tobias Klöffel, Sagarmoy Mandal, and Bernd Meyer — Interdisciplinary Center for Molecular Materials and Computer Chemistry Center, FAU Erlangen-Nürnberg, Germany
The most important advantage of plane-wave basis sets is that wave functions can be transformed efficiently from reciprocal to real space and back by using the Fast-Fourier transform (FFT) algorithm. This allows to evaluate the kinetic and potential energy in reciprocal and real space, respectively, where both operators are diagonal. This reduces the computational cost for applying the Hamilton operator from N2 to N logN. However, the scalability of current FFT libraries is rather limited on today’s HPC systems, which offer large numbers of compute nodes, each of them with many cores. Here we present our optimization of the FFTX library of the Quantum Espresso software package. Data distribution and communication patterns have been revised to make optimal use of combined MPI and OpenMP parallelization. Scalability is further increased by combining FFTs into batches and by introducing overlapping computation and communication. We implemented the revised FFTX library in our optimized version of the CPMD code [1], and we demonstrate the achieved acceleration by a series of benchmark simulations.
[1] T. Klöffel, G. Mathias, B. Meyer, Comput. Phys. Commun. 260
(2021) 107745