Add operator <

Heat_method_3/include/CGAL/Heat_method_3/Intrinsic_Delaunay_Triangulation_3.h

@@ -137,6 +137,11 @@ namespace Intrinsic_Delaunay_Triangulation_3 {
        struct Vertex_descriptor {
          halfedge_descriptor hd;
 
+         bool operator<(const Vertex_descriptor& other) const
+         {
+           return hd < other.hd;
+         }
+         
          Vertex_descriptor(const halfedge_descriptor& hd)
            : hd(hd)
          {}

Heat_method_3/test/Heat_method_3/heat_method_intrinsic_surface_mesh_test.cpp

@@ -131,6 +131,8 @@ int main()
 
   //source set tests
   Heat_method hm(sm, vertex_distance_map);
+  hm.add_source(* vertices(sm).first);
+  hm.update();
 #if 0
   source_set_tests(hm,sm);
   //cotan matrix tests