Use prolongate_and_add() in Multigrid::level_v_step()

diff --git a/include/deal.II/multigrid/multigrid.templates.h b/include/deal.II/multigrid/multigrid.templates.h
index b8a7f3ba6ebd2456b75587324966b987dd13f918..d8f40db0f2f7455910f0704e834cac24b1f15c06 100644 (file)
--- a/include/deal.II/multigrid/multigrid.templates.h
+++ b/include/deal.II/multigrid/multigrid.templates.h
@@ -139,11 +139,9 @@ Multigrid<VectorType>::level_v_step(const unsigned int level)
 
   // do coarse grid correction
   this->signals.prolongation(true, level);
-  transfer->prolongate(level, t[level], solution[level - 1]);
+  transfer->prolongate_and_add(level, solution[level], solution[level - 1]);
   this->signals.prolongation(false, level);
 
-  solution[level] += t[level];
-
   // get in contribution from edge matrices to the defect
   if (edge_in != nullptr)
     {