If this flag is set the parallel version is generated. It is necessary to recompile all files. The parallelization requires that MPI is installed on the machine and the position of the libraries must be specified in the makefile.
There is one minor ``technical'' problem with MPI: MPI requires an include file mpi.h, which is usually not F90 free format conform-able (CRAY is one exception). Therefore the include file mpi.h must be copied to the directory vasp.4 and converted to f90 style and named mpif.h. This can be done using the following lines:
> cp ...mpi.../include/mpi.h mpif.h > ./convert mpif.hThe convert utility converts a F77 fortran file to a F90 free format file and is supplied in the vasp.4 directory. (On the Cray T3E at IDRIS this is for instance not required, and mpif.h can be found in one of the default include pathes).