# if defined SINGLE_PRECISION
#    define PRECISION sp
#    define SENDROUTINE mppsend_sp
#    define RECVROUTINE mpprecv_sp
#    define MPI_TYPE MPI_REAL
# else
#    define PRECISION dp
#    define SENDROUTINE mppsend_dp
#    define RECVROUTINE mpprecv_dp
#    define MPI_TYPE MPI_DOUBLE_PRECISION
# endif

   SUBROUTINE ROUTINE_LNK( pt2d, cd_type, psgn, kextj)
      !!---------------------------------------------------------------------
      !!                   ***  routine mpp_lbc_north_icb  ***
      !!
      !! ** Purpose :   Ensure proper north fold horizontal bondary condition
      !!              in mpp configuration in case of jpn1 > 1 and for 2d
      !!              array with outer extra halo
      !!
      !! ** Method  :   North fold condition and mpp with more than one proc
      !!              in i-direction require a specific treatment. We gather
      !!              the 4+kextj northern lines of the global domain on 1
      !!              processor and apply lbc north-fold on this sub array.
      !!              Then we scatter the north fold array back to the processors.
      !!              This routine accounts for an extra halo with icebergs
      !!              and assumes ghost rows and columns have been suppressed.
      !!
      !!----------------------------------------------------------------------
      REAL(PRECISION), DIMENSION(:,:), INTENT(inout) ::   pt2d     ! 2D array with extra halo
      CHARACTER(len=1)        , INTENT(in   ) ::   cd_type  ! nature of pt3d grid-points
      !                                                     !   = T ,  U , V , F or W -points
      REAL(wp)                , INTENT(in   ) ::   psgn     ! = -1. the sign change across the
      !!                                                    ! north fold, =  1. otherwise
      INTEGER                 , INTENT(in   ) ::   kextj    ! Extra halo width at north fold
      !
      INTEGER ::   ji, jj, jr
      INTEGER ::   ierr, itaille
      INTEGER ::   ipj, ij, iproc, ijnr, ii1, ipi, impp
      !
      REAL(PRECISION), DIMENSION(:,:)  , ALLOCATABLE  ::  ztab_e, znorthloc_e
      REAL(PRECISION), DIMENSION(:,:,:), ALLOCATABLE  ::  znorthgloio_e
      !!----------------------------------------------------------------------
#if defined key_mpp_mpi
      !
      ipj=4
      ALLOCATE(        ztab_e(jpiglo, 1-kextj:ipj+kextj)       ,       &
     &            znorthloc_e(jpimax, 1-kextj:ipj+kextj)       ,       &
     &          znorthgloio_e(jpimax, 1-kextj:ipj+kextj,ndim_rank_north)    )
      !
# if defined SINGLE_PRECISION
      ztab_e(:,:)      = 0._sp
      znorthloc_e(:,:) = 0._sp
# else
      ztab_e(:,:)      = 0._dp
      znorthloc_e(:,:) = 0._dp
# endif
      !
      ij = 1 - kextj
      ! put the last ipj+2*kextj lines of pt2d into znorthloc_e 
      DO jj = jpj - ipj + 1 - kextj , jpj + kextj
         znorthloc_e(1:jpi,ij)=pt2d(1:jpi,jj)
         ij = ij + 1
      END DO
      !
      itaille = jpimax * ( ipj + 2*kextj )
      !
      IF( ln_timing ) CALL tic_tac(.TRUE.)
#if defined key_mpp_mpi
      CALL MPI_ALLGATHER( znorthloc_e(1,1-kextj)    , itaille, MPI_TYPE,    &
         &                znorthgloio_e(1,1-kextj,1), itaille, MPI_TYPE,    &
         &                ncomm_north, ierr )
#endif
      !
      IF( ln_timing ) CALL tic_tac(.FALSE.)
      !
      ijnr = 0
      DO jr = 1, ndim_rank_north            ! recover the global north array
         iproc = nfproc(jr)
         IF( iproc /= -1 ) THEN
            impp = nfimpp(jr)
            ipi  = nfjpi(jr)
            ijnr = ijnr + 1
            DO jj = 1-kextj, ipj+kextj
               DO ji = 1, ipi
                  ii1 = impp + ji - 1       ! corresponds to mig(ji) but for subdomain iproc
                  ztab_e(ii1,jj) = znorthgloio_e(ji,jj,ijnr)
               END DO
            END DO
         ENDIF
      END DO

      ! 2. North-Fold boundary conditions
      ! ----------------------------------
      CALL lbc_nfd( ztab_e(:,1-kextj:ipj+kextj), cd_type, psgn, kextj )

      ij = 1 - kextj
      !! Scatter back to pt2d
      DO jj = jpj - ipj + 1 - kextj , jpj + kextj
         DO ji= 1, jpi
            pt2d(ji,jj) = ztab_e(ji+nimpp-1,ij)
         END DO
         ij  = ij +1
      END DO
      !
      DEALLOCATE( ztab_e, znorthloc_e, znorthgloio_e )
      !
#endif
   END SUBROUTINE ROUTINE_LNK 

#    undef PRECISION
#    undef SENDROUTINE
#    undef RECVROUTINE
#    undef MPI_TYPE