What is the difference between these two compilers, mpif90 and mpifort? Both seems to be for Fortran 90 code. Both got installed when I installed openMPI on Linux. Are the usage (compiler options) different?
The MPI standard says nothing about the various compiler wrappers, except that "Some MPI libraries are shipped together with special compilation scripts".
Thus, one needs to consult OpenMPI's documentation:
http://www.open-mpi.org/faq/?category=mpi-apps#mpifort-vs-mpif77-and-mpif90
The gist of it is that modern fortran compilers are better about determining if code should be treated like fortran 2008, fortran 2003, fortran 90, fortran 77, or whatever. OpenMPI wants folks to just use mpifort, and let the fortran front-end compiler do the work.