ESMF_ArrayReduce Subroutine

  subroutine ESMF_ArrayReduce(array, result, reduceflag, rootPET, vm, rc)
!
! !ARGUMENTS:
    type(ESMF_Array),       intent(inout)         :: array
    real(ESMF_KIND_R8),     intent(out), optional :: result
    type(ESMF_Reduce_Flag), intent(in)            :: reduceflag
    integer,                intent(in)            :: rootPET
    type(ESMF_VM),          intent(in),  optional :: vm
    integer,                intent(out), optional :: rc  
!
! !DESCRIPTION:
!     Fully reduce the entire Array into a single {\tt result} on {\tt rootPET}
!     according to the operation specified in {\tt reduceflag}. Only root must
!     specify a valid result argument.
!
!     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[{[result ]}]
!        Argument into which to reduce the Array. Only root
!        must provide a valid {\tt result} 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[{[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
    
    result = real(0.,ESMF_KIND_R8)  ! quiet down compiler warnings while not fully implemented
    
  end subroutine ESMF_ArrayReduce