MPI build issues

[AlexandreLapene]

CMake allows for building without MPI, USE_MPI is an option but VTK uses MPI. So building PAMELA without MPI does not make sense and does not work. Two possibilities:

• Make MPI mandatory for PAMELA - not a big fan as PAMELA can be used in serial
• Make consistent IF_DEF in the source code with proper MPI and no-MPI vtk modules - my pick
  Thanks!

[rrsettgast]

Option 2. GEOSX proper has a bunch of these things in the GeosxConfig.hpp.in/.hpp file generated from CMAKE. I suggest using a nomenclature of PAMELA_USE_OPTION for all your preprocessor variables.

[Antoine948398]

@rrsettgast we have also these types of nomenclature. The problem is that some VTK packages are automatically compiled with MPI, some are not. So if you compile PAMELA with VTK, it will assume that you have the MPI version installed... which is bad I agree with you @AlexandreLapene I will implement your second point.