Flux update with OpenMP

[ivan-pi]

See issue described in https://fortran-lang.discourse.group/t/fixing-an-openmp-race-condition/3102 and https://fortran-lang.discourse.group/t/graph-coloring/3116

A similar problem is described by PoP CoE: https://co-design.pop-coe.eu/patterns/indirect-reductions-atomic-large-data-structure.html

A best practice described to solve the problem is explicit dependencies: https://co-design.pop-coe.eu/best-practices/multideps-indirect-reductions-large-data-structure.html

See also:

• Advanced OpenMP
• OpenMP Programming Workshops
• OpenMP Offloading: Day3-1.pdf
• Lecture 12: Introduction to OpenMP (Part 1)
• Lecture 12: Introduction to OpenMP (Part 2)

[ivan-pi]

More presentations addressing explicit dependency graphs:

• Programming OpenMP - Task Dependencies
• OpenMP 5.0 and Beyond: Taking Good Care of the Node in Exascale?
• Tasking in OpenMP 5.0
• Programming OpenMP