Event Information:

• Thu

  22

  May

  2025

  SC Seminar: Raju Ram

  11:45Hybrid (Room 32-349 and via Zoom)

  Raju Ram, Bosch, Leonberg, Germany

  Title: Hybrid Parallel Preconditioners in Domain Decomposition Methods: Achieving Robustness and Scalability in the Solution of Large-Scale Linear Systems
  

  Abstract:

  Krylov subspace solvers like GMRES and preconditioners such as ILU are widely used for solving large-scale linear systems in simulations. Scalable parallel implementations are required to exploit the increasing parallelism provided by modern hardware. We develop a hybrid parallel Crout ILU preconditioner within the linear solver library GaspiLS, leveraging the GASPI programming model. At the process level, domain decomposition methods such as additive Schwarz (AS) and restricted additive Schwarz (RAS) are employed, and the multilevel nested dissection method is applied at the thread level.
  Our implementation achieves 80 percent parallel efficiency on 1280 cores (64 sockets) when solving the convection-diffusion equation. Compared to the PETSc linear solver library, it delivers comparable baseline performance and better scalability at higher socket counts. When solving large-scale real-world computational fluid dynamics problems, scalability is maintained up to 1920 cores (96 sockets), with the RAS preconditioner successfully controlling iteration growth, unlike the AS variant. Further tests on ill-conditioned matrices from the SuiteSparse collection demonstrate the robustness and generality of the preconditioner, successfully solving problems that the traditional ILU(0) preconditioner fails to solve.
  Our approach offers a generic, algebraic, and scalable preconditioner that enables productivity for the domain expert in solving large-scale, sparse linear systems.

  How to join online

  You can join online via Zoom, using the following link:
  https://uni-kl-de.zoom-x.de/j/69269239534?pwd=Z9UOzMpkhMjrxVhll3d49sNHFe9Fd1.1