1 files changed, 1 insertions, 1 deletions
diff --git a/mg2d.c b/mg2d.c
index 25a1759..d09796b 100644
--- a/mg2d.c
+++ b/mg2d.c
@@ -192,7 +192,7 @@ static int mg_solve_subgrid(MG2DContext *ctx, MG2DLevel *level, int allow_exact)
             /* prolongate the coarser-level correction */
             mg2di_timer_start(&level->timer_prolong);
             ret = mg2di_gt_transfer(level->transfer_prolong, level->prolong_tmp,
-                                    level->child->solver->u_base);
+                                    level->child->solver->u_exterior);
             mg2di_timer_stop(&level->timer_prolong);
             if (ret < 0)
                 return ret;