MPI-AMRVAC is a parallel adaptive mesh refinement framework aimed at solving partial differential equations by a number of different numerical schemes. It is written in Fortran 90 and uses MPI for parallelisation across many CPUs.

In modern HPC infrastructure, most compute power is however not in the CPUs but in accelerators such as GPUs. In order to make use of this compute power, we have enabled MPI-AMRVAC to run on GPUs using OpenACC, enabling larger-scale simulations than ever before.

I will discuss the advantages and challenges of OpenACC in our experience, and highlight the achieved performance improvement in MPI-AMRVAC on both Snellius and LUMI.