Make comparator const

diff --git a/include/deal.II/numerics/vector_tools.templates.h b/include/deal.II/numerics/vector_tools.templates.h
index bcc6399baef717f696d44a6b6e0a9e8c5ef8ae1b..cab72cbc41bf96a2602646b74dfb39b101f1c20b 100644 (file)
--- a/include/deal.II/numerics/vector_tools.templates.h
+++ b/include/deal.II/numerics/vector_tools.templates.h
@@ -6625,7 +6625,7 @@ namespace VectorTools
     struct PointComparator
     {
       bool operator ()(const std::array<types::global_dof_index,dim> &p1,
-                       const std::array<types::global_dof_index,dim> &p2)
+                       const std::array<types::global_dof_index,dim> &p2) const
       {
         for (unsigned int d=0; d<dim; ++d)
           if (p1[d] < p2[d])