ESMF_ArrayReduceFarray Subroutine

  subroutine ESMF_ArrayReduceFarray(array, farray, reduceflag, rootPET, &
    dimList, tile, vm, rc)
!
! !ARGUMENTS:
    type(ESMF_Array),           intent(inout)           :: array
    real(ESMF_KIND_R8), target, intent(out),  optional  :: farray(:,:)
    type(ESMF_Reduce_Flag),     intent(in)              :: reduceflag
    integer,                    intent(in)              :: rootPET
    integer,                    intent(in)              :: dimList(:)
    integer,                    intent(in),   optional  :: tile
    type(ESMF_VM),              intent(in),   optional  :: vm
    integer,                    intent(out),  optional  :: rc  
!
! !DESCRIPTION:
!     Reduce the dimensions specified in {\tt dimList} of the Array object 
!     into {\tt farray} on {\tt rootPET} according to the operation specified 
!     in {\tt reduceflag}. Only root must provide a valid {\tt farray} argument.
!     
!     This partial reduction operation is tile specific, i.e. only a single
!     DistGrid tile of the Array will be reduced. The tile can be selected
!     by the optional {\tt tile} argument. The shape of the provided 
!     {\tt farray} argument must match that of the Array tile reduced by the
!     dimensions specified in {\tt dimList}.
!      
!
!     This version of the interface 
!     implements the PET-based blocking paradigm: Each PET of the VM must issue
!     this call exactly once for {\em all} of its DEs. The
!     call will block until all PET-local data objects are accessible.
!
!     The arguments are:
!     \begin{description}
!     \item[array] 
!        The {\tt ESMF\_Array} object across which data will be scattered.
!     \item[{[farray]}]
!        Fortran array into which to reduce the Array. Only root
!        must provide a valid {\tt farray} argument.
!     \item[reduceflag] 
!        Reduction operation. See section \ref{const:reduce} for a list of 
!        valid reduce operations. There will be options that determine the 
!        sequence of operations to ensure bit-wise reproducibility.
!     \item[rootPET]
!          root.
!     \item[dimList]
!        List of Array dimensions to be reduced.
!     \item[{[tile]}]
!        The DistGrid tile in {\tt array} to reduce into {\tt farray}.
!        By default tile 1 of {\tt farray} will be reduced.
!     \item[{[vm]}]
!        Optional {\tt ESMF\_VM} object of the current context. Providing the
!        VM of the current context will lower the method's overhead.
!     \item[{[rc]}] 
!          Return code; equals {\tt ESMF\_SUCCESS} if there are no errors.
!     \end{description}
!
!EOPI
!------------------------------------------------------------------------------
    integer                 :: localrc      ! local return code

    ! initialize return code; assume routine not implemented
    localrc = ESMF_RC_NOT_IMPL
    if (present(rc)) rc = ESMF_RC_NOT_IMPL
    
  end subroutine ESMF_ArrayReduceFarray