This requires a new file - libxMPI.f - which contains the interface to the MPI library and modifications to the makefile and the machine specific include file to provide information about the MPI libraries and include files.

Updating Crystal98.

This example refers to a port to a PC running Linux with the Portland Group compiler - ports to other machines should be straightforward if the local MPI documentation is available.
We assume that CRYSTAL98 has been copied from the CD and that the directores ./src and ./src/Xmakes exist.

Download  libxMPI.f, makefile.MPI, and, Linux-pgf-MPI.inc

Copy libxMPI.f and makefile.MPI to ./src
Copy Linux-pgf-MPI.inc to; ./src/Xmakes.;

Then try:

cd src
make -f Makefile.MPI ARCH=Linux-pgf-MPI
make -f Makefile.MPI ARCH=Linux-pgf-MPI parallel

Note that the only machine specific instructions are contained in Linux-pgf-MPI where the compiler flags and the variable PLIB must be defined.