1. How to access ghost nodes?

    Answer: Following Fortran code illustrates how to see which nodes in the mesh are ghost nodes.

    subroutine query_ghosts( mesh )
  type( atlas_Mesh ), intent(in) :: mesh

  type( atlas_mesh_Nodes ) :: nodes
  type( atlas_Field ) :: field_ghost
  integer, pointer :: ghost(:)
  integer :: nb_ghost, ghost_begin, jnode

  nodes = mesh%nodes()
  field_ghost = nodes%ghost()
  call field_ghost%data( ghost )

  nb_ghost = 0
  ghost_begin = nodes%size()
  do jnode = 1, nodes%size()
    if( ghost(jnode) ) then
      nb_ghost = nb_ghost + 1
      ghost_begin = min( ghost_begin, jnode )
    endif
  enddo
end subroutine

    In early atlas versions, ghost nodes were located in between owned nodes. In later versions the default behaviour is that all ghost nodes are located at the end. This means that using above snippet, all ghost nodes start from "ghost_begin" to "nodes%size()"
    We will try to make it easier in subsequent atlas versions.