use check_convergence() to stop optimization when vertices do not move enough

the convergence ratio is set to 0.001 by default

+ fix the use of moving_vertices for iterations after the first one

Mesh_2/include/CGAL/Mesh_2/Mesh_global_optimizer_2.h

@@ -76,8 +76,8 @@ public:
    * Constructor
    */
   Mesh_global_optimizer_2(CDT& cdt,
-                        const FT& freeze_ratio = 0., //no criterion
                         const FT& convergence_ratio = 0., //no criterion
+                        const FT& freeze_ratio = 0., //no criterion
                         const MoveFunction move_function = MoveFunction())
     : cdt_(cdt)
     , sq_freeze_ratio_(freeze_ratio * freeze_ratio)
@@ -137,6 +137,8 @@ public:
       // Update mesh with those moves
       update_mesh(moves, moving_vertices);
 
+      // ToDo : freeze vertices that do not move enough
+
       move_function_.after_move(cdt_);
 
 #ifdef CGAL_MESH_2_OPTIMIZER_VERBOSE
@@ -162,7 +164,8 @@ public:
     timer.stop();
     std::cerr << std::endl;
     if ( check_convergence() )
-      std::cerr << "Convergence reached" << std::endl;
+      std::cerr << "Convergence reached for ratio "
+                << convergence_ratio_ << std::endl;
     std::cerr << "Total optimization time: " << timer.time()
               << "s" << std::endl << std::endl;
 #endif
@@ -316,14 +319,10 @@ private:
       //function not available, see Constrained_triangulation_2
       cdt_.remove(v);
       cdt_.insert(new_position);
-      //todo : insert new faces to outdated_faces
 
       if( is_time_limit_reached() )
         break;
     }
-
-    // Update cdt
-    moving_vertices.clear();
   }
 
 public:

Mesh_2/include/CGAL/lloyd_optimize_mesh_2.h

@@ -10,7 +10,8 @@ namespace CGAL
 
   template<typename CDT>
   void lloyd_optimize_mesh_2(CDT& cdt,
-                             const unsigned int nb_iterations)
+                             const unsigned int nb_iterations = 1,
+                             const double convergence_ratio = 0.001)
   {
     typedef typename CDT::Geom_traits Gt;
     typedef CGAL::Lipschitz_sizing_field_2<Gt> Lip_sizing;
@@ -22,9 +23,11 @@ namespace CGAL
       ++vit)
         points.insert(vit->point());
     Lip_sizing size(points.begin(), points.end());
-    
+
+
     typedef CGAL::Mesh_2::Lloyd_move_2<CDT, Lip_sizing> Mf;
-    CGAL::Mesh_2::Mesh_global_optimizer_2<CDT, Mf> lloyd(cdt);
+    CGAL::Mesh_2::Mesh_global_optimizer_2<CDT, Mf> lloyd(cdt,
+                                                         convergence_ratio);
     lloyd.set_sizing_field(size);
     lloyd(nb_iterations);
   }