fix warning: -1 assignment to unsigned

diff --git a/include/deal.II/numerics/vector_tools_constraints.templates.h b/include/deal.II/numerics/vector_tools_constraints.templates.h
index b941e2cdbe01ec77dc0228f1d5295a9ce1594272..35f6e84b42b47bb5ece1b0a3ec8ab2c97cbc3484 100644 (file)
--- a/include/deal.II/numerics/vector_tools_constraints.templates.h
+++ b/include/deal.II/numerics/vector_tools_constraints.templates.h
@@ -1494,7 +1494,7 @@ namespace VectorTools
             // constraint indices will get the normal that contain the other
             // indices.
             Tensor<1, dim> normal;
-            unsigned       constrained_index = -1;
+            unsigned int   constrained_index = numbers::invalid_unsigned_int;
             for (unsigned int d = 0; d < dim; ++d)
               if (is_constrained[d])
                 {