Parallel Matrix-free Multigrid for Extreme Scale Computing

Date: 28/01/2021, 2 pm
speaker: Dr. Ulrich Ruede (FAU Erlangen-Nürnberg and CERFACS Toulouse)
This webinar will focus on parallel matrix-free multigrid for extreme scale computing.
Multigrid is one of the most efficient algorithms to solve linear systems for elliptic partial differential equations, and matrix-free variants are essential to reach the best possible performance. This will be demonstrated for positive definite systems as they arise in the discretization of the gyrokinetic Poisson equation, as well as indefinite systems that originate in viscous flow problems.
During this webinar, special attention will be given to the coarse grids of the multigrid hierarchy to avoid that they become a sequential bottleneck. Modern sparse direct methods and their approximate form using block-low-rank approximations will be used.
The talk will include a scalability study, aiming to solve a linear system with more than ten trillion unknowns, equivalent to a solution vector as big as 80 TByte in main memory.
Dr. Ulrich Ruede (FAU Erlangen-Nürnberg and CERFACS, Toulouse) will host this webinar, organized by the European Energy-Oriented Center of Excellence (EoCoE). 
The webinar is free and open to everyone, and will be recorded to be later available on the EoCoE YouTube channel.