The seminar series will continue in the summer semester of 2023.
Past Seminars
Talk by Dr. Karl Rupp — 25 Jan. 2023
Date: January 25, 2023, 4–5:30 p.m. CET. Coffee and tea from 4–4:30 p.m.
Speaker: Dr. Karl Rupp (TU Wien), ORCID
Location:
Weyertal 121, 50931 Cologne
RRZK building (Google Maps, OpenStreetMap), Entrance
Room 1.03
Title: 15 Years of GPUs for Computational Science: Past, Present and Future
Abstract: General purpose computations on Graphics Processing Units (GPUs) have become widely available with the first release of the CUDA toolkit in summer 2007. In the 15 years that have followed, GPUs have become widely adopted for many general purpose computations in computational science. And yet, there is still an ongoing debate whether “GPUs are worth it” from a productivity point of view. This talk revisits various technological developments in the GPU landscape over these 15 years and discusses current GPU functionality available in popular software libraries such as PETSc. Based on the lessons learned from the past, current developments and promises are evaluated in order to derive an outlook on where computational science using GPUs is headed.
Talk by Dr.-Ing. Michael Klemm — 23 Jan. 2023
Date: January 23, 2023, 4–5:30 p.m. CET (talk from about 4–5 p.m., followed by a discussion).
Speaker: Dr.-Ing. Michael Klemm (Principal Member of Technical Staff, HPC Center of Excellence, AMD), ORCID
Location:
Weyertal 121, 50931 Cologne
RRZK building (Google Maps, OpenStreetMap), Entrance
Room 1.03
Title: AMD EPYC Processors and Instinct Accelerators — The Journey to Exascale and Beyond
Abstract: High Performance Computing (HPC) is a prevalent and widespread tool to solve advanced, scientific and commercial problems. Simulating the structure of molecules, computational fluid dynamics, quantum chemistry, or astrophysics are just a few examples of the many domains that employ HPC systems at all scales to solve every-day and not so every-day problems. AMD has a rich history of providing hardware that helps satisfy the computational demands of today's HPC workloads. In this presentation, we will recap the developments and innovations at AMD in the recent past and how they led to the current design of AMD EPYC Processors and AMD Instinct Accelerators. Hardware and software are equally important, and so we will spend a bit of time also on software implications. We will close the talk with an outlook on what will be coming in the near-term future.
Talk by Dr. Alexander Heinlein — 18 Jan. 2023
Date: January 18, 2023, 4–5:30 p.m. CET. Coffee and tea from 4–4:30 p.m.
Speaker: Dr. Alexander Heinlein (Delft University of Technology), ORCID
Location:
Weyertal 121, 50931 Cologne
RRZK building (Google Maps, OpenStreetMap), Entrance
Room 1.03
Title: Fast and Robust Overlapping Schwarz Preconditioners in Trilinos — Highly Scalable Algorithms and Their Efficient Implementation
Abstract: The Trilinos library is an object-oriented software framework for the solution of large-scale, complex multi-physics engineering and scientific problems on new and emerging high-performance computing (HPC) architectures. It provides a collection of interoperable software packages enabling the development of algorithms reaching parallel scalability up to the largest supercomputers available.
This talk will discuss different aspects of Trilinos for the example of the FROSch (Fast and Robust Overlapping Schwarz) preconditioning framework, which is part of the Trilinos package ShyLU. FROSch implements multilevel Schwarz preconditioners, which are algebraic, i.e., which can be constructed using only the fully assembled parallel distributed system matrix. Making use of the software infrastructure of Trilinos, FROSch allows for the parallel solution of extremely large problems. Numerical results for various problems indicating parallel scalability up to more than 200,000 MPI ranks will be presented. Moreover, node-level parallelization on CPUs as well as GPUs using the Kokkos programming model through the Tpetra linear algebra framework will be discussed.
Talk by Prof. Dr. Martin Kronbichler — 7 Dec. 2022
Date: December 7, 2022, 4–5:30 p.m. CET. Coffee and tea from 4–4:30 p.m.
Speaker: Prof. Dr. Martin Kronbichler (University of Augsburg), ORCID
Location:
Weyertal 121, 50931 Cologne
RRZK building (Google Maps, OpenStreetMap), Entrance
Room 1.03
Title: Efficient Implementations of High-Order Finite-Element Methods
Abstract: The talk focuses on the efficient implementation of high-order methods in the context of continuous and discontinuous finite elements applied to linear and nonlinear partial differential equations on complex geometries. The core algorithmic ingredient is the matrix-free operator evaluation (matrix-vector product), for which fast quadrature schemes for cell and face integrals based on a technique called sum factorization are employed. The algorithm selection for achieving a high throughput is demonstrated, guided by performance analysis, as well as the scalability to large-scale parallel machines. The best algorithms come with an arithmetic intensity of one to five flop/byte, with memory transfer primarily due to the access into input and output vectors as well as some geometry or variable coefficient data. As a result of our optimizations, many downstream solvers, such as explicit time stepping, smoothers in multigrid methods, or conjugate gradient solvers, are now no longer dominated by the matrix-vector product but by vector operations instead. To overcome this limitation, we consider the whole solution chain and fuse the memory access between different stages of an algorithm. The effect of these optimizations on the performance on contemporary CPU and GPU architectures are illustrated and results are shown of fluid dynamics simulations implemented with computational kernels from the deal.II finite element library.