Welcome

• Michel Verleysen

Room: CYCL01

Exascale Computing: A User’s Perspective

• Paul Fischer (Aragone National Laboratory)

Room: CYCL01 We discuss design and performance issues for computational science applications on GPU-based HPC platforms from a user/developer perspective. We focus particularly on the strong-scale limit, where HPC users typically run in practice. This limit is closely tied to the local problem size, that is, the number of degrees-of-freedom (or grid points) per MPI rank, which reflects the amount of parallel work for domain-decomposition-based parallelism. As this number decreases, communication effects become important. On GPUs, kernel launch latency is another factor controlling achievable speed-ups. We discuss several features that distinguish algorithmic optimization strategies for GPU- based HPC platforms from their predecessor, fine-grained distributed-memory, platforms such as IBM’s BG series. As concrete examples, we consider the performance of high-order spectral element methods for incompressible flow on all of Mira ( > 1 M ranks), all of Summit (> 27,000 ranks), and all of Frontier (> 70,000 ranks). We discuss optimizations for each of these platforms, with a particular focus on the Poisson problem, which is the stiffest and therefore most time-consuming substep in Navier-Stokes time advancement. Examples are presented in the context of Nek5000/RS, which is a high-order open-source code for thermal-fluid transport problems. --- Paul Fischer received his Ph.D. in mechanical engineering from MIT in 1989.After postdoctoral research at MIT and Caltech, he joined Brown University as an assistant professor in the Applied Mathematics department. In 1998, he was hired as a mathematician at Argonne and was promoted to senior scientist in 2008. He is a world leader in computational fluid dynamicis. More information about Paul Fisher on the Aragone National Laboratory website: https://www.anl.gov/profile/paul-f-fischer

CÉCI technical talk Room: CYCL01 Topics: - Lemaitre4 - Lyra - Common storage (CEPH) - Hercules and Dragon - Help us help you

Tier-1 and Tier-0 technical talk

• Orian Louant (Université de Liège)

Room: CYCL01

Population genomic analysis using CÉCI clusters

• Surabhi Ranavat

Room: CYCL01

Scaling self-supervised pre-training on Lucia and Lumi

• Renaud Vandeghen (ULiège)

Room: CYCL01

Molecular Dynamics Simulations of multimillion-atom systems using the power of Lucia and Lumi GPUs

• David Dellemme

Room: CYCL01

Integrating AI-Driven heterogenous HPC for Advanced Optical Design

• Nicolas Roy (UNamur)

Room: CYCL01

An unbounded Multigrid Poisson solver within an adaptive multiresolution framework for the Navier-Stokes equations, MURPHY

• Gilles Poncelet (UCLouvain)

Room: CYCL01