required_local Function

private pure function required_local(d) result(needed)

Minimum interior cell count this rank must hold. A non-periodic rank needs at least halo_width cells. A periodic decomposition needs one more: the wrap send skips the duplicated endpoint node (global node n_global == node 1), so the periodic edge ranks send cells [2 .. h+1] / [n_local-h .. n_local-1], which require n_local >= halo_width + 1. The bound is applied to every rank (not just the edges) so the feasibility guarantee is uniform.

Arguments

Type IntentOptional Attributes Name
type(decomp_t), intent(in) :: d

Return Value integer