1: !
  2: !
  3:        subroutine ex7f(vec,comm)

 5:  #include include/finclude/petsc.h
 6:  #include include/finclude/petscvec.h
  7: !
  8: !  This routine demonstates how a computational module may be written
  9: !  in Fortran and called from a C routine, passing down PETSc objects.
 10: !

 12:        PetscScalar      two
 13:        Vec              vec
 14:        MPI_Comm         comm
 15:        PetscErrorCode ierr
 16:        PetscMPIInt rank

 18:        two  = 2.0

 20: !
 21: !     The Objects vec,comm created in a C routine are now
 22: !     used in fortran routines.
 23: !
 24:        call VecSet(vec,two,ierr)
 25:        call MPI_Comm_rank(comm,rank,ierr)

 27: !
 28: !  Now call C routine from Fortran, passing in the vector, communicator
 29: !
 30:        call ex7c(vec,comm,ierr)
 31: !
 32: !     IO from the fortran routines may cause all kinds of
 33: !
 34:  100   format ('[',i1,']',' Calling VecView from Fortran')
 35:        write(6,100) rank
 36: !
 37: !  Now Call a Petsc Routine from Fortran
 38: !
 39:        call VecView(vec,PETSC_VIEWER_STDOUT_WORLD,ierr)
 40:        return
 41:        end

 43: