KERNEL(gradient)
  FORALL_CELLS_EXT()
    ON_EDGES
      grad(EDGE) = SIGN*(b(CELL2)-b(CELL1))
    END_BLOCK
  END_BLOCK
END_BLOCK

KERNEL(div)
  FORALL_CELLS_EXT()
    ON_PRIMAL
      div_ij=0.
      FORALL_EDGES
        div_ij = div_ij + SIGN*LE_DE*u(EDGE)
      END_BLOCK
      divu(CELL) = div_ij / AI
    END_BLOCK
  END_BLOCK
END_BLOCK