gf: mesh. const_iterator and add cbegin

- for meshes :
clean concept w/ doc, add cbegin, and changed
iterator to const_iterator (more standard name).

triqs/gfs/block.hpp

@@ -142,7 +142,7 @@ namespace triqs { namespace gfs {
    public boost::iterator_facade< block_gf_iterator<Target,Opt>, typename Target::view_type , boost::forward_traversal_tag, typename Target::view_type  > {
     friend class boost::iterator_core_access;
     typedef gf_view<block_index,Target,Opt> big_gf_t;
-    typedef typename big_gf_t::mesh_t::iterator mesh_iterator_t;
+    typedef typename big_gf_t::mesh_t::const_iterator mesh_iterator_t;
     big_gf_t big_gf;
     mesh_iterator_t mesh_it;
 

triqs/gfs/gf.hpp

@@ -35,8 +35,8 @@ namespace triqs { namespace gfs {
 
  // GENERALISE matrxi TO DEFAULT
  template<typename Variable, typename Opt=void> struct mesh;
- template<typename Variable, typename Target=matrix_valued, typename Opt=void> class gf;         // the value class
+ template<typename Variable, typename Target=matrix_valued, typename Opt=void> class gf;         // the regular type
- template<typename Variable, typename Target=matrix_valued, typename Opt=void> class gf_view;    // the view class
+ template<typename Variable, typename Target=matrix_valued, typename Opt=void> class gf_view;    // the view type
 
  // various implementation traits
  namespace gfs_implementation { // never use using of this... 

triqs/gfs/meshes/discrete.hpp

@@ -61,9 +61,11 @@ namespace triqs { namespace gfs {
    mesh_point_t operator[](index_t i) const { return mesh_point_t (*this,i);}
 
    /// Iterating on all the points...
-   typedef  mesh_pt_generator<discrete_mesh> iterator;
+   typedef  mesh_pt_generator<discrete_mesh> const_iterator;
-   iterator begin() const { return iterator (this);}
+   const_iterator begin() const { return const_iterator (this);}
-   iterator end()   const { return iterator (this, true);}
+   const_iterator end()   const { return const_iterator (this, true);}
+   const_iterator cbegin() const { return const_iterator (this);}
+   const_iterator cend()   const { return const_iterator (this, true);}
 
    /// Mesh comparison
    bool operator == (discrete_mesh const & M) const { return (_dom == M._dom) ;} 

triqs/gfs/meshes/linear.hpp

@@ -37,6 +37,8 @@ namespace triqs { namespace gfs {
    typedef size_t index_t; 
    typedef typename domain_t::point_t  domain_pt_t;
 
+   linear_mesh () : _dom(), L(0), a_pt(0), b_pt(0), xmin(0), xmax(0), del(0), meshk(half_bins) {}
+   
    linear_mesh (domain_t const & dom, double a, double b, size_t n_pts, mesh_kind mk) :
      _dom(dom), L(n_pts), a_pt(a), b_pt(b), meshk(mk) {
      switch(mk) {
@@ -57,8 +59,6 @@ namespace triqs { namespace gfs {
      xmax = xmin + del*(L-1);
    }
 
-   linear_mesh () : _dom(), L(0), a_pt(0), b_pt(0), xmin(0), xmax(0), del(0), meshk(half_bins) {}
-
    domain_t const & domain() const { return _dom;}
    size_t size() const { return L; }
    double delta() const { return del; }
@@ -110,9 +110,11 @@ namespace triqs { namespace gfs {
    public:
 
    /// Iterating on all the points...
-   typedef  mesh_pt_generator<linear_mesh> iterator;
+   typedef  mesh_pt_generator<linear_mesh> const_iterator;
-   iterator begin() const { return iterator (this);}
+   const_iterator begin() const { return const_iterator (this);}
-   iterator end()   const { return iterator (this, true);}
+   const_iterator end()   const { return const_iterator (this, true);}
+   const_iterator cbegin() const { return const_iterator (this);}
+   const_iterator cend()   const { return const_iterator (this, true);}
 
    /// Mesh comparison
    bool operator == (linear_mesh const & M) const { return ((_dom == M._dom) && (size() ==M.size()) && (std::abs(xmin - M.xmin)<1.e-15) && (std::abs(xmax - M.xmax)<1.e-15));} 

triqs/gfs/meshes/product.hpp

@@ -107,9 +107,11 @@ namespace triqs { namespace gfs {
    mesh_point_t operator()(typename Meshes::index_t ... i) const { return (*this)[std::make_tuple(i...)];}
 
    /// Iterating on all the points...
-   typedef  mesh_pt_generator<mesh_product> iterator;
+   typedef  mesh_pt_generator<mesh_product> const_iterator;
-   iterator begin() const { return iterator (this);}
+   const_iterator begin() const { return const_iterator (this);}
-   iterator end()   const { return iterator (this, true);}
+   const_iterator end()   const { return const_iterator (this, true);}
+   const_iterator cbegin() const { return const_iterator (this);}
+   const_iterator cend()   const { return const_iterator (this, true);}
 
    /// Mesh comparison
    friend bool operator == (mesh_product const & M1, mesh_product const & M2) { return M1.m_tuple==M2.m_tuple; }