FETools::Compositing::compute_nonzero_components(): add assert

diff --git a/include/deal.II/fe/fe_tools.templates.h b/include/deal.II/fe/fe_tools.templates.h
index 48512f06fcd8e0fef6413c09ef114d8f3219d9c8..ee985f56eafa72d54cf78a7ba8385f4e03ad1f4d 100644 (file)
--- a/include/deal.II/fe/fe_tools.templates.h
+++ b/include/deal.II/fe/fe_tools.templates.h
@@ -375,7 +375,10 @@ namespace FETools
       const bool do_tensor_product)
     {
       AssertDimension(fes.size(), multiplicities.size());
-
+      Assert(
+        fes.size() > 0,
+        ExcMessage(
+          "This function only makes sense if at least one FiniteElement is provided."));
       // first count the number of dofs and components that will emerge from the
       // given FEs
       unsigned int n_shape_functions = 0;