1: !
  2: !    "$Id: ex7f.F,v 1.22 2001/08/22 18:00:07 balay Exp $";
  3: !
  4:        subroutine ex7f(vec,comm)

 6:  #include include/finclude/petsc.h
 7:  #include include/finclude/petscvec.h
  8: !
  9: !  This routine demonstates how a computational module may be written
 10: !  in Fortran and called from a C routine, passing down PETSc objects.
 11: !

 13:        PetscScalar      two
 14:        Vec              vec
 15:        MPI_Comm         comm
 16:        integer          ierr,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(two,vec,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: !     grief while linking. *_SYS_LIB in PETSC_ARCH/variables is supporsed
 34: !     to take care of it.
 35: !
 36:  100   format ('[',i1,']',' Calling VecView from Fortran')
 37:        write(6,100) rank
 38: !
 39: !  Now Call a Petsc Routine from Fortran
 40: !
 41:        call VecView(vec,PETSC_VIEWER_STDOUT_WORLD,ierr)
 42:        return
 43:        end

 45: