This variable is used only in the case of the creation of a parallel executable.
It can possess only one out of two possible settings. One MPIBIT setting is
8x4, which means you are going to use MPI libraries which support 8-byte
long REAL and 4-byte long INTEGER variables. This is also the default value for
the MPIBIT variable. The other setting is 8x8, which means that you are
going to use MPI libraries which support 8-byte long REAL and 4-byte long INTEGER
variables whereas the deMon2k program itself uses 8-byte long INTEGER. Note that
the MPIBIT variable itself does not automatically sets the compilation flags for
8-byte long INTEGER. Instead, the compile option for 8-byte long INTEGER has to
be set additionally with the FFLAGS variable (ifort: -i8; gfortran: -fdefault-integer-8. See also the Linux-x86_64.mpi.ifort file in the
database directory of the shipped version as an example for the 8x8
setting of the MPIBIT variable.