diff --git a/Mesh/periodical.h b/Mesh/periodical.h
index 255fa2f9d1eb4f2da457c325fcda3427af2535bd..59cbafd95783bf9159fa469f1c67555bfd2d94a7 100644
--- a/Mesh/periodical.h
+++ b/Mesh/periodical.h
@@ -29,5 +29,6 @@ class voroMetal3D{
   void print_geo_line_loop(int,std::vector<int>&,std::vector<int>&,std::ofstream&);
   void print_geo_face_loop(int,std::vector<int>&,std::ofstream&);
   void correspondance(double);
+  bool correspondance(double,double,double,double);
   bool equal(double,double,double);
 };