Actual source code: ex7f.F90

  1: !
  2: !
  3:        subroutine ex7f(vec, comm)
  4: #include <petsc/finclude/petscvec.h>
  5:          use petscvec
  6:          implicit none
  7: !
  8: !  Demonstrates how a computational module may be written
  9: !  in Fortran and called from a C routine, passing down PETSc objects.
 10: !

 12:          PetscScalar, parameter ::  two = 2.0
 13:          Vec vec
 14:          MPI_Comm comm
 15:          PetscErrorCode ierr
 16:          PetscMPIInt rank

 18: !
 19: !     The Objects vec,comm created in a C routine are now
 20: !     used in Fortran routines.
 21: !
 22:          PetscCall(VecSet(vec, two, ierr))
 23:          PetscCallMPI(MPI_Comm_rank(comm, rank, ierr))
 24:          PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, rank, ierr))

 26: !
 27: !  Now call routine from Fortran, passing in the vector, communicator
 28: !
 29:          PetscCall(ex7c(vec, comm, ierr))
 30: !
 31: !     IO from the Fortran routines may cause all kinds of
 32: !
 33: ! 100   format ('[',i1,']',' Calling VecView from Fortran')
 34: !       write(6,100) rank
 35: !
 36: !  Now Call a PETSc Routine from Fortran
 37: !
 38:          PetscCall(VecView(vec, PETSC_VIEWER_STDOUT_WORLD, ierr))
 39:        end