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ForestClaw / forestclaw

Quadtree/octree adaptive PDE solver based based on p4est.
http://www.forestclaw.org
BSD 2-Clause "Simplified" License
58 stars 22 forks source link

Support for OpenMP in build system? #97

Closed donnaaboise closed 6 years ago

donnaaboise commented 9 years ago

Originally reported by: Donna Calhoun (Bitbucket: donnaaboise, GitHub: donnaaboise)

It is easy enough to add -fopenmp to the configure options, but we could also think about adding a check in the build system (although most compilers these days probably support openmp ...)

donnaaboise commented 8 years ago

Original comment by Donna Calhoun (Bitbucket: donnaaboise, GitHub: donnaaboise):

That would be great. But then if we "officially" support OpenMP, it would be good to test it with MPI. I tried, but found that the performance was quite slow, which was surprising. I am not really sure how MPI and OpenMP interact.

Would your student be able to do a few ForestClaw runs to possibly test the OpenMP/MPI combination? That would be great!

On the other hand, I found that at least on the desktop, MPI was faster than OpenMP, so I am not sure what is really gained by using OpenMP, unless we use it at the grid level, i.e. over i,j loops. Currently, I am only using it to parallelize the code at the patch level.

donnaaboise commented 8 years ago

Original comment by Carsten Burstedde (Bitbucket: cburstedde, GitHub: cburstedde):

Ok I'll have my grad student program something.

donnaaboise commented 6 years ago

I think it is easy enough to include openMP in the configure options - no need to make the build system more complicated.