Alya towards Exascale: Algorithmic Scalability using PSCToolkit

TL;DR

This paper details an upgrade to the Alya simulation code, integrating PSCToolkit's advanced parallel linear solvers to enhance scalability and efficiency for exascale computing in fluid dynamics simulations.

Contribution

The paper introduces a new software module interfacing Alya with PSCToolkit, enabling scalable Krylov and Algebraic MultiGrid solvers for large-scale Navier-Stokes simulations.

Findings

PSCToolkit solvers outperform original Alya solvers in scalability.

Significant improvements in parallel efficiency on wind farm airflow benchmarks.

Demonstrates Alya's readiness for exascale computing environments.

Abstract

In this paper, we describe an upgrade of the Alya code with up-to-date parallel linear solvers capable of achieving reliability, efficiency and scalability in the computation of the pressure field at each time step of the numerical procedure for solving a Large Eddy Simulation formulation of the incompressible Navier-Stokes equations. We developed a software module in Alya's kernel to interface the libraries included in the current version of PSCToolkit, a framework for the iterative solution of sparse linear systems on parallel distributed-memory computers by Krylov methods coupled to Algebraic MultiGrid preconditioners. The Toolkit has undergone various extensions within the EoCoE-II project with the primary goal of facing the exascale challenge. Results on a realistic benchmark for airflow simulations in wind farm applications show that the PSCToolkit solvers significantly outperform the original versions of the Conjugate Gradient method available in the Alya's kernel in terms of scalability and parallel efficiency and represent a very promising software layer to move the Alya code towards exascale.