[jason.ryon]

Sorry for the beginner question:

I have seen multiple posts about how using Gamma MPI is beneficial to improving parallel efficiency.

1. How do I see what MPI (gamma, openmpi, etc...) I am using?

2. How do I change it to something else (gamma for example) in OpenFOAM 1.6? From what I read, it is something like:
a. Edit ~OpenFOAM/OpenFOAM-1.6/etc/bashrc to be "gamma" instead of openmpi in the "WM_MPLIB"
b. cd $FOAM_SRC/Pstream
c. ./Allwmake
Now when I try to decomposePar it says:
decomposePar: error while loading shared libraries: libPstream.so: cannot open shared object file: No such file or directory

Can somebody please point me to how to install gamma mpi and also set it up with OpenFOAM 1.6?

Thanks,
Jason

[bastil]

From what I know:
1. It only makes really sence on ethernet clusters no ib or similar
2. last recommendation was to use open-mx instead of gamma since it is much easier to compile.
TO use it build open-mx (http://open-mx.gforge.inria.fr/) from source and afterwards compile openmpi against open-mx.

Regards

[jason.ryon]

Does Gamma effect parallel scalability on a single node (i.e. from 2 to 3 to 4 cores on a single processor)?

I am still in the single-box testing phase before I get to ethernet or ib.

Thanks,
Jason