MGTransferGlobalCoarsening: add assert

diff --git a/include/deal.II/multigrid/mg_transfer_global_coarsening.h b/include/deal.II/multigrid/mg_transfer_global_coarsening.h
index ea86730e573e4de9c129535807689fd953615e99..aaf96ed803779d384ec783af1e1b1adf57f89239 100644 (file)
--- a/include/deal.II/multigrid/mg_transfer_global_coarsening.h
+++ b/include/deal.II/multigrid/mg_transfer_global_coarsening.h
@@ -481,6 +481,13 @@ MGTransferGlobalCoarsening<dim, VectorType>::copy_to_mg(
 {
   (void)dof_handler;
 
+  Assert(
+    initialize_dof_vector,
+    ExcMessage(
+      "To be able to use this function, a function to initialize an internal "
+      "DoF vector has to be provided in the constructor of "
+      "MGTransferGlobalCoarsening."));
+
   for (unsigned int level = dst.min_level(); level <= dst.max_level(); ++level)
     initialize_dof_vector(level, dst[level]);
 
@@ -514,6 +521,13 @@ MGTransferGlobalCoarsening<dim, VectorType>::interpolate_to_mg(
 {
   (void)dof_handler;
 
+  Assert(
+    initialize_dof_vector,
+    ExcMessage(
+      "To be able to use this function, a function to initialize an internal "
+      "DoF vector has to be provided in the constructor of "
+      "MGTransferGlobalCoarsening."));
+
   const unsigned int min_level = transfer.min_level();
   const unsigned int max_level = transfer.max_level();