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-   -   what's dummy Pstream for?? (http://www.cfd-online.com/Forums/openfoam-installation/98149-whats-dummy-pstream.html)

quaintchewster March 4, 2012 12:55

what's dummy Pstream for??
 
I tried compiling OF 2.1.0 on a cluster with its native MPI. The make system of OpenFoam is really puzzeling. And I was confused by the dummy Pstream.

I think dummy Pstream was designed for serial running. But why libOpenFoam.so is forced to be linked with dummy version libPstream.so ? How this libOpenFoam.so with the dummy Pstream code can do parallel running??

wyldckat March 4, 2012 13:54

Greetings quaintchewster,

It's simple: the dummy Pstream acts as a place holder, sort-of of a stub. This way it's possible to have a single OpenFOAM installation that can easily work with any number of MPI libraries/toolboxes as you want to, without having to recompile the whole OpenFOAM source code.

For example, if you were conducting experiments to compare several MPI libraries, such as Open-MPI 1.4.3 and 1.5.3 vs MPICH2 1.4.1, you would then have the following folders in "$FOAM_LIBBIN":
  • dummy
  • openmpi-1.4.3
  • openmpi-1.5.3
  • mpich2-1.4.1
Inside each one you will then have a dedicated Pstream library, along with other MPI dependent libraries.

For more about how wmake works: OpenFoam Installation in Redhat Enterprise linux 5 - post #22
For more about how the OpenFOAM works on the shell: Advanced tips for working with the OpenFOAM shell environment

Best regards,
Bruno

quaintchewster March 4, 2012 14:29

wyldckat

Thank you !!
If only I read these a week ago. It took me so much time to make it.


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