A Multi-Layer Parallelization Scheme for Pseudospectral Computations of Fluid Turbulence
Universidad de Buenos Aires and CONICET, Argentina
GHOST (the Geophysical High-Order Suite for Turbulence) is an accurate and highly scalable pseudospectral code that solves a variety of PDEs often encountered in studies of turbulent flows. Some of the equations that can be solved with GHOST include rotating and stratified flows using the Boussinesq approximation, compressible and incompressible magnetohydrodynamic (MHD) equations for space physics, and superfluids and Bose-Einstein condensates using the Gross-Pitaevskii equation. Recently, support for the computation of trajectories of Lagrangian particles, test particles (charged particles in a conducting fluid or a plasma), and inertial particles was added. The code uses a multi-layer parallelization method combining MPI, OpenMP and CUDA, and can run efficiently in laptops and small clusters, as well as to scale up to 100,000 CPU cores (and GPUs) in production runs in supercomputers. In this talk I will present some of the parallelization schemes used in GHOST, including a hybrid MPI-OpenMP domain decomposition of the pseudospectral grids, CUDA support, I/O handling, and performance measurements to illustrate the utility of the methods.
Pablo Mininni is a professor in the Physics Department at UBA where he was also the chair of the department from 2011 to 2015. He received his diploma in 1999 and his doctoral degree in 2003, both in physics and from the University of Buenos Aires (UBA) in Argentina. He works on the numerical and theoretical study of turbulent flows, with applications in astrophysics, geophysics, and atmospheric sciences. In the field of fluid dynamics, his expertise includes parallelization methods for computational fluid dynamics, the application of statistical methods for the characterization and analysis of turbulent flows, spectral analysis of multi-scale and multi-physics phenomena, and sub-grid modeling for turbulent flows. Applications include the solar cycle and turbulent dynamos, magnetic reconnection, rotating and stratified turbulence, and superfluid turbulence.
Tuesday, March 7, 2017
2:00 pm – 3:00 pm
Mesa Lab, Main Seminar Room