TY - JOUR A1 - Wende, Florian A1 - Marsman, Martijn A1 - Kim, Jeongnim A1 - Vasilev, Fedor A1 - Zhao, Zhengji A1 - Steinke, Thomas T1 - OpenMP in VASP: Threading and SIMD T2 - International Journal of Quantum Chemistry N2 - The Vienna Ab initio Simulation Package (VASP) is a widely used electronic structure code that originally exploits process-level parallelism through the Message Passing Interface (MPI) for work distribution within and across nodes. Architectural changes of modern parallel processors urge programmers to address thread- and data-level parallelism as well to benefit most from the available compute resources within a node. We describe for VASP how to approach for an MPI + OpenMP parallelization including data-level parallelism through OpenMP SIMD constructs together with a generic high-level vector coding scheme. We can demonstrate an improved scalability of VASP and more than 20% gain over the MPI-only version, as well as a 2x increased performance of collective operations using the multiple-endpoint MPI feature. The high-level vector coding scheme applied to VASP's general gradient approximation routine gives up 9x performance gain on AVX512 platforms with the Intel compiler. Y1 - 2018 UR - https://opus4.kobv.de/opus4-zib/frontdoor/index/index/docId/7230 IS - Emerging Architectures in Computational Chemistry SP - e25851 PB - Wiley Online Library ER -