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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.