Draft: C++ port of horizontal/mo_lib_gradients.F90

Port the functions of mo_lib_gradients.F90 to C++, with C bindings. Untested, but compiles.

src/horizontal/mo_lib_gradients.cpp

@@ -58,8 +58,8 @@ void grad_fd_norm_lib(const T* psi_c,
             // Compute the normal derivative by the finite difference approximation
             // See Bonaventura and Ringler MWR 2005
             grad_norm_psi_e_view(je, jk, jb) =
-                psi_c_view(edge_cell_idx_view(je, jb, 1), jk, edge_cell_blk_view(je, jb, 1)) -
-                psi_c_view(edge_cell_idx_view(je, jb, 0), jk, edge_cell_blk_view(je, jb, 0)) *
+                (psi_c_view(edge_cell_idx_view(je, jb, 1), jk, edge_cell_blk_view(je, jb, 1)) -
+                psi_c_view(edge_cell_idx_view(je, jb, 0), jk, edge_cell_blk_view(je, jb, 0))) *
                 inv_dual_edge_length_view(je, jb);
         });
         Kokkos::fence();