Choosing time-steppers to build parallel-in-time algorithms for geophysical and astrophysical flows


Mouloud Kessar, Univ Savoie Mont-Blanc. 1 décembre 2023 15:00 TLR edp
Abstract:

Geophysical phenomenon such as magnetic field reversal are a challenge to observe numerically. They are quite demanding in terms of numerical resources, and with the upcoming generation of exascale computers, it becomes necessary to ensure an efficient and full usage of such clusters. In geophysical and astrophysical flows, the classical method for parallelism is data parallelism. The physical domain is distributed across a large number of cores. The scaling of such a distribution can quickly saturate when the number of cores increases. Introducing an additional pipeline parallelism, through a distribution of a time interval across a number of cores, is a potential solution to use a larger number of cores, and perform numerical simulations of magnetic field reversals. When used by parallel in time schemes, time-steppers need to validate a few of criteria. We extracted 18 time-steppers from literature, from second to eighth order of accuracy. We will compare the accuracy and efficiency of those time steppers in the context of liquid planetary cores, in order to identify potential candidates to build parallel in time schemes.