can't smooth boundary cells in non-periodic problems

src/HRSC/smoother.jl

@@ -161,6 +161,7 @@ function smooth_C0_1st_order!(bulk_v, cell_v, mesh::Mesh2d, isperiodic_x=true, i
   v_iter = dg1d.CellDataIterator(mesh, bulk_v)
 
   for (k,(v,cell)) in enumerate(zip(v_iter,cells))
+    dg1d.is_boundarycell(cell) && continue
     # left, right, up, down
     l, r, d, u = cell.neighbors
     # left-down, left-up, right-down, right-up
@@ -197,6 +198,7 @@ function smooth_C0_2nd_order!(bulk_v, cell_v, mesh::Mesh2d, isperiodic_x=true, i
   v_iter = dg1d.CellDataIterator(mesh, bulk_v)
 
   for (k,(v,cell)) in enumerate(zip(v_iter,cells))
+    dg1d.is_boundarycell(cell) && continue
     # left, right, up, down
     l, r, d, u = cell.neighbors
     # left-down, left-up, right-down, right-up