Update halo cells of state%ub from the current interior solution and BC types (NODAL / finite-difference path). Rank-aware: only edge ranks act.
Called (via apply_bcs) at the top of spatial_discretization::compute_resid(state), after halo_exchange has populated the interior-side halos.
On exit: - state%is_periodic is set consistently with state%bc_left / state%bc_right. - On rank 0: state%ub(:, 1-h : 0) is updated according to bc_left. - On rank n_ranks - 1: state%ub(:, n_local+1 : n_local+h) is updated according to bc_right. - On inner ranks: no writes (halo_exchange already filled the cells).
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| type(solver_state_t), | intent(inout) | :: | state |
Solver instance state. |