Speaker: Professor P.K. Yeung, Georgia Tech
Date and Time: September 23, 2:00-3:00 p.m.
Location: Scheller, Room 102
Host: CSE Assistant Professor Spencer Bryngelson

Title: Turbulence on the verge of the Exascale: pseudo-spectral algorithms and particle tracking

Abstract: With Exascale Computing having officially arrived in mid 2022, we report on the development of a new Exascale-ready GPU algorithm for three-dimensional homogeneous turbulence.  Our goal is to push the envelope in simulation size while optimizing code performance aggressively by fully exploiting the particular strengths of leadership-class hardware and software.  In particular on “Frontier" at Oak Ridge Leadership Computing Facility (OLCF), OpenMP offloading to GPUs, fast GPU-aware message passing and reduced needs for host-device data copying are putting turbulence simulations at 35 trillion grid points resolution on the verge of becoming a reality, while also raising hopes for other computational challenges previously out of reach. In this talk, we discuss progress achieved on precursor machines to Frontier, with the benefit of close contact with vendor experts as part of a highly selective Center for Accelerated Application Readiness (CAAR) program at OLCF. The  technical focus of our CAAR project is on Fourier pseudo-spectral methods which have considerable impact beyond the study of turbulence via direct numerical simulations. However we also address the additional challenges of particle tracking necessary for studies of turbulent dispersion, for which most elements of an highly scalable algorithm developed on “Frontera" at the Texas Advanced Computation Center (TACC) have been ported to GPUs for future work on Frontier, as well.

Bio: Professor P.K. Yeung received his PhD at Cornell University in 1989, and joined the faculty in the School of Aerospace Engineering at Georgia Tech in 1992. Professor Yeung's research is focused on massive computations of turbulence by needs for both new physical insights and advancements in theory of modeling. He has a long record of success in accessing and using facilities at external national-scale supercomputer centers operated by the US Department of Energy or supported by the National Science Foundation. In recent years especially notable advancements have been achieved using GPUs on the supercomputers Titan, Summit, and (soon) Frontier at the Oak Ridge Leadership Computing Facility. Currently his group holds the record for the largest turbulence simulation worldwide, at a resolution of over 5 trillion grid points, as presented at the SC'19 Conference.