2009/12/15 troy <troy@resophonic.com>

alt.boost.cmake uses cmake's standard detection of MPI... our docs are
very terse:

http://sodium.resophonic.com/boost-cmake/current-docs/externals/mpi.html

See the cmake docs for FindMPI. I assume the best way is to tweak some
cache variables post-installation.

I have not found any FindMPI.cmake file (even in MPICH2 or OpenMPI project directories), but only a MPI.cmake file, in <boost-source-root-dir>/tools/build/CMake/externals. There, by adding the following lines, I was successful in building Boost.MPI with OpenMPI rather than with MPICH2:
---------------------------------------------------------------------------------
set(MPI_INCLUDE_PATH /usr/include/openmpi-x86_64)
set(MPI_COMPILE_FLAGS -I/usr/include/openmpi-x86_64)
set(MPI_LINK_FLAGS -L/usr/lib64/openmpi/lib -L/usr/lib64/openmpi/lib/openmpi -lmpi_cxx -lmpi)
set(MPI_LIBRARIES /usr/lib64/openmpi/lib/libmpi.so /usr/lib64/openmpi/lib/libmpi_cxx.so)
set(MPI_FOUND 1)
---------------------------------------------------------------------------------
[Note: the file attached is the corresponding patch]

However, you may see that I am not a CMake specialist, and that I have hard-coded the pathes of OpenMPI. So, if some of you know better CMake than I do, do not hesitate to improve OpenMPI detection.

D.