Fortran Parallel Examples

Examples of parallel runtimes from native Fortran syntax. direct MPI operations or Fortran Coarrays are in separate repos.

Examples include:

• do concurrent: including Fortran 202x "reduce" syntax
• OpenACC: directive for Fortran
• openmp: OpenMP threading examples

do concurrent

do concurrent was enhanced in Fortran 202x including "reduce" syntax. Intel oneAPI requires OpenMP to parallelize do concurrent. The LLVM Flang compiler team has written a thoughtful article on the characteristics and limitations of do concurrent parallelization.

OpenMP

macOS users may need to install OpenMP library.

OpenACC

Not every compiler supports OpenACC. For example, Intel oneAPI does not support OpenACC, but provides a migration tool from OpenACC to OpenMP.

NVIDIA HPC SDK generally shows 10s of percent runtime improvement with OpenACC on this example. Other compilers like GCC might show little advantage.