euler2d_cudaFortran

2nd order Godunov solver for 2d Euler equations written in CUDA Fortran

Note: If your more interested into c++ for GPUs, have a look at version using C++/kokkos for performance portability: https://github.com/pkestene/euler2d_kokkos

Short description

This code solves the 2D Euler equations in a regular cartesian mesh using a 2nd order godunov-based finite volume scheme.

There are actually two version, one is using the so called cuda fortran programming model, and the other is designed with the newer fortran standard parallelism (stdpar).

Nvhpc compiler for Cuda Fortran and stdpar

You need to have installed [nvhpc] to build this application. then, e.g

module load nvhpc/23.11

By default, nvfortran will detect visible GPU available on the system, and generate code for it.

# for the cuda fortran version
cd cuf
make
# for the stdpar version
cd stdpar
make

Parameter file

Parameters: edit file test.nml

In the cuf version, there are two differents variants of the numerical scheme which are different in term of allocated memory. Use parameter implementationVersion = 0 or 1 to change.

Initial condition: a discontinuity along the domain diagonal

Example of use

./euler2d_gpu ./test.nml

Output: VTK ascii file using VTK Image Data format

Visualization: paraview --data=euler2d_..vti

The cuf version was written in 2013 (with the PGI compiler), and the stdpar version in 2022.

In terms of performance,

• stdpar version is able to run at more than 500 Mcell-updates per seconds on A100, using large domain (2048x2048).
• cuda-fortran version has roughly the same performance (maybe slightly less performant).