Make the ghost points explicit in prolongation

1 files changed, 5 insertions, 3 deletions

diff --git a/mg2d.c b/mg2d.c
index 84985d7..25a1759 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);
+                                    level->child->solver->u_base);
             mg2di_timer_stop(&level->timer_prolong);
             if (ret < 0)
                 return ret;
@@ -444,8 +444,10 @@ static int mg_levels_init(MG2DContext *ctx)
             cur->transfer_prolong->dst.step[0] = cur->solver->step[0];
             cur->transfer_prolong->dst.step[1] = cur->solver->step[1];
 
-            cur->transfer_prolong->src.size[0] = cur->child->solver->domain_size[0];
-            cur->transfer_prolong->src.size[1] = cur->child->solver->domain_size[1];
+            cur->transfer_prolong->src.start[0] = -FD_STENCIL_MAX;
+            cur->transfer_prolong->src.start[1] = -FD_STENCIL_MAX;
+            cur->transfer_prolong->src.size[0] = cur->child->solver->domain_size[0] + 2 * FD_STENCIL_MAX;
+            cur->transfer_prolong->src.size[1] = cur->child->solver->domain_size[1] + 2 * FD_STENCIL_MAX;
             cur->transfer_prolong->src.step[0] = cur->child->solver->step[0];
             cur->transfer_prolong->src.step[1] = cur->child->solver->step[1];