Add AssertThrow to catch the not implemented case

diff --git a/include/deal.II/matrix_free/operators.h b/include/deal.II/matrix_free/operators.h
index 4118825da36c8cac0612991d7ff5d8cffe45269c..5273980806c3fd9878506b5910398553830db4e1 100644 (file)
--- a/include/deal.II/matrix_free/operators.h
+++ b/include/deal.II/matrix_free/operators.h
@@ -1831,7 +1831,12 @@ namespace MatrixFreeOperators
                VectorType,
                VectorizedArrayType>::MassOperator()
     : Base<dim, VectorType, VectorizedArrayType>()
-  {}
+  {
+    AssertThrow(
+      IsBlockVector<VectorType>::value == false,
+      ExcNotImplemented(
+        "This class only supports the non-blocked vector variant of the Base operator because only a single FEEvaluation object is used in the apply function."));
+  }