bgeot_mesh_structure.h

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 Copyright (C) 1999-2017 Yves Renard

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/**@file bgeot_mesh_structure.h
   @author  Yves Renard <Yves.Renard@insa-lyon.fr>
   @date November 5, 1999.
   @brief Mesh structure definition
*/

#ifndef BGEOT_MESH_STRUCTURE_H__
#define BGEOT_MESH_STRUCTURE_H__

#include <set>
#include "bgeot_convex_structure.h"
#include "dal_tree_sorted.h"

namespace bgeot {

  struct APIDECL mesh_convex_structure {
    typedef std::vector<size_type> ind_pt_ct;

    pconvex_structure cstruct;       /* type of convex.                  */
    ind_pt_ct pts;                   /* point list indices.               */

    pconvex_structure structure() const { return cstruct; }
    pconvex_structure &structure() { return cstruct; }
    mesh_convex_structure() : cstruct(0) {}
  };

  struct convex_face
  {
    convex_face(size_type element, short_type face) : cv(element), f(face) {}
    size_type cv = -1;
    short_type f = -1;
    bool valid() const {return (cv != size_type(-1)) && (f != short_type(-1));}
    static convex_face invalid_face() {return {size_type(-1), short_type(-1)};}
  };

  /**@addtogroup mesh */
  ///@{
  /** Mesh structure definition.
   *   At this point, the mesh is just a graph: the points have no
   *  associated coordinates
   */
  class APIDECL mesh_structure {

  public :

    typedef std::vector<size_type> ind_cv_ct;
    typedef std::vector<size_type> ind_set;
    typedef gmm::tab_ref_index_ref<ind_cv_ct::const_iterator,
                            convex_ind_ct::const_iterator> ind_pt_face_ct;
    typedef dal::dynamic_array<ind_cv_ct, 8> point_ct;

  protected :

    dal::dynamic_tas<mesh_convex_structure, 8> convex_tab;
    point_ct points_tab;

  public :

    /// Return the list of valid convex IDs
    const dal::bit_vector &convex_index() const
      { return convex_tab.index(); }
    /// Return the list of valid convex IDs of a given dimension
    dal::bit_vector convex_index(dim_type) const;
    /// The total number of convexes in the mesh
    size_type nb_convex() const { return convex_tab.card(); }
    /// The number of convex indexes from 0 to the index of the last convex
    size_type nb_allocated_convex() const
      { return convex_tab.index().last_true()+1; }
    /// Return true if i is in convex_index()
    bool is_convex_valid(size_type i) { return (convex_tab.index())[i]; }
    size_type nb_max_points() const { return points_tab.size(); }
    /// Return true if the point i is used by at least one convex
    bool is_point_valid(size_type i) const { return !(points_tab[i].empty()); }
    /** Return a container to the list of points attached to convex ic.
        They are ordered according to structure_of_convex(ic) */
    const ind_cv_ct &ind_points_of_convex(size_type ic)
      const { return convex_tab[ic].pts; }
    /// Return the "local" index for point ip of the mesh
    size_type local_ind_of_convex_point(size_type ic, size_type ip) const;
    /// Return the pconvex_structure of the convex ic.
    pconvex_structure structure_of_convex(size_type ic) const
    { return convex_tab[ic].cstruct; }
    /// Return the number of points of convex ic.
    short_type nb_points_of_convex(size_type ic) const
    { return convex_tab[ic].cstruct->nb_points(); }
    /// Return the number of faces of convex ic.
    short_type nb_faces_of_convex(size_type ic) const
    { return short_type(convex_tab[ic].cstruct->nb_faces()); }
    /// Exchange two point IDs
    void swap_points(size_type i, size_type j);
    /// Exchange two convex IDs
    void swap_convex(size_type cv1, size_type cv2);

    template<class ITER>
    size_type add_convex_noverif(pconvex_structure cs, ITER ipts,
                                 size_type to_index = size_type(-1));
    /** Insert a new convex in the mesh_structure.
        @param cs the structure of the new convex.
        @param ipts an iterator over a sequence of integers (point IDs of the convex nodes).
        @param present an optional argument, contains true on return if the convex already exists in the mesh_structure.
        @return the convex ID
    */
    template<class ITER>
    size_type add_convex(pconvex_structure cs,
                         ITER ipts, bool *present = 0);
    template<class ITER> size_type add_simplex(dim_type dim, ITER ipts)
      { return add_convex(simplex_structure(dim), ipts); }
    size_type add_segment(size_type a, size_type b);
    /** Remove the convex ic */
    void sup_convex(size_type ic);
    /** Remove a convex given its points
        @param nb the number of points for the convex
        @param ipts an iterator over the list of point IDs of the convex
    */
    template<class ITER>
    void sup_convex_with_points(ITER ipts, short_type nb);
    void sup_segment(size_type a, size_type b)
      { size_type t[2]; t[0] = a; t[1] = b; sup_convex_with_points(&t[0], 2); }
    /** Insert a new convex corresponding to face f of the convex ic */
    size_type add_face_of_convex(size_type ic, short_type f);
    /** Insert new convexes corresponding to the faces of the convex ic */
    void add_faces_of_convex(size_type ic);
    /** build a new mesh, such that its convexes are the faces of the
        convexes of the previous one */
    void to_faces(dim_type n);
    /** build a new mesh, such that its convexes are the edges of the
        convexes of the previous one */
    void to_edges();

    size_type nb_convex_with_edge(size_type i1, size_type i2);
    void convex_with_edge(size_type i1, size_type i2,
                          std::vector<size_type> &ipt) const;

    /** Return a container of the convexes attached to point ip */
    const ind_cv_ct &convex_to_point(size_type ip) const
    { return points_tab[ip]; }
    /** Return a container of the points attached (via an edge) to point ip */
    void ind_points_to_point(size_type, ind_set &) const;

    /** Return true if the convex contains the listed points.
        @param ic the convex ID.
        @param nb the number of points which are searched in ic.
        @param pit an iterator to the list of points searched.
    */
    template<class ITER>
      bool is_convex_having_points(size_type ic,short_type nb, ITER pit) const;

    /** Return true if the face of the convex contains the given list of points */
    template<class ITER>
    bool is_convex_face_having_points(size_type ic, short_type face_num,
                                      short_type nb, ITER pit) const;

    /** Return a container of the (global) point number for face f or convex ic */
    ind_pt_face_ct ind_points_of_face_of_convex(size_type ic,
                                                short_type f) const;

    size_type memsize() const;
    /** Reorder the convex IDs and point IDs, such that there is no
        hole in their numbering. */
    void optimize_structure();
    /// erase the mesh
    void clear();
    void stat();

    /** Return in s a list of neighbours of a given convex face.
        @param ic the convex id.
        @param f the face number of the convex.
        @param s the resulting ind_set.
     */
    void neighbours_of_convex(size_type ic, short_type f, ind_set &s) const;

    /** Return in s a list of neighbours of a given convex sharing the
        intersection of a given list of faces
        @param ic the convex id.
        @param f the face number of the convex.
        @param s the resulting ind_set.
     */
    void neighbours_of_convex(size_type ic,
                              const std::vector<short_type> &ftab,
                              ind_set &s) const;

    /** Return a list of neighbours of a given convex.
        @param ic the convex id.
        @param  s the resulting ind_set.
    */
    void neighbours_of_convex(size_type ic, ind_set &s) const;

    /** Return a neighbour convex of a given convex face.
        @param ic the convex id.
        @param f the face number of the convex.
        @return size_type(-1) if there is no neighbour to this convex and
        the index of the first neighbour found otherwise.
    */
    size_type neighbour_of_convex(size_type ic, short_type f) const;

    /**Return a face of the neighbouring element that is adjacent to the given face
       @param ic the convex id.
       @param f the face number of the convex.
       @return convex_face that contains the neighbours convex id and the adjacent
       face number, or convex_face::invalid_face() otherwise.
    */
    convex_face adjacent_face(size_type ic, short_type f) const;

    bool is_convex_having_neighbour(size_type ic, short_type f) const
    { return (neighbour_of_convex(ic, f) != size_type(-1)); }

    /** Convex ID of the first convex attached to the point ip. */
    size_type first_convex_of_point(size_type ip) const
    { return points_tab[ip].empty() ?  size_type(-1) : points_tab[ip][0]; }
    /** Find the local index of the point of global index ip with respect to
     *        the convex cv.
     *  @return local index (a number smaller than
     *        nb_points_of_convex(first_convex_of_point(ip))) or size_type(-1) if
     *  the point is not found.
     */
    size_type ind_in_convex_of_point(size_type ic, size_type ip) const;
  };
  ///@}




  /** Return the cuthill_mc_kee ordering on the convexes */
  void APIDECL cuthill_mckee_on_convexes(const bgeot::mesh_structure &ms,
                                         std::vector<size_type> &cmk);

  template<class ITER>
    bool mesh_structure::is_convex_having_points(size_type ic,
                                              short_type nb, ITER pit) const {
    const ind_cv_ct &pt = ind_points_of_convex(ic);
    for (short_type i = 0; i < nb; ++i, ++pit)
      if (std::find(pt.begin(), pt.end(), *pit) == pt.end())
        return false;
    return true;
  }

  template<class ITER> bool
  mesh_structure::is_convex_face_having_points(size_type ic, short_type face_num,
                                               short_type nb, ITER pit) const {
    ind_pt_face_ct pt = ind_points_of_face_of_convex(ic, face_num);
    for (short_type i = 0; i < nb; ++i, ++pit)
      if (std::find(pt.begin(), pt.end(), *pit) == pt.end()) return false;
    return true;
  }

  template<class ITER>
  size_type mesh_structure::add_convex_noverif(pconvex_structure cs,
                                               ITER ipts, size_type is) {
    mesh_convex_structure s; s.cstruct = cs;
    size_type nb = cs->nb_points();

    if (is != size_type(-1)) { sup_convex(is); convex_tab.add_to_index(is,s); }
    else is = convex_tab.add(s);

    convex_tab[is].pts.resize(nb);
    for (size_type i = 0; i < nb; ++i, ++ipts)
      { convex_tab[is].pts[i] = *ipts; points_tab[*ipts].push_back(is); }
    return is;
  }

  template<class ITER>
  size_type mesh_structure::add_convex(pconvex_structure cs,
                                       ITER ipts, bool *present) {
    if (present) *present = false;
    for (size_type i = 0; i < points_tab[*ipts].size(); ++i)
      if (structure_of_convex(points_tab[*ipts][i]) == cs &&
          is_convex_having_points(points_tab[*ipts][i], cs->nb_points(), ipts))
        { if (present) *present = true; return points_tab[*ipts][i]; }
    return add_convex_noverif(cs, ipts);
  }

  template<class ITER>
  void mesh_structure::sup_convex_with_points(ITER ipts, short_type nb) {
    if (nb) {
      for (size_type i = 0; i < points_tab[*ipts].size(); ++i)
        if (is_convex_having_points(points_tab[*ipts][i], nb, ipts))
          sup_convex(points_tab[*ipts][i]);
    }
  }


  /* ********************************************************************* */
  /*                                                                       */
  /*  Gives the list of edges of a mesh.                                   */
  /*                                                                       */
  /* ********************************************************************* */

  /* maybe this should be removed from the matlab interface and obsoleted */
  struct APIDECL edge_list_elt  {
    size_type i, j;
    size_type cv;
    inline bool operator < (const edge_list_elt &e) const {
      if (i < e.i) return true;
      if (i > e.i) return false;
      if (j < e.j) return true; else if (j > e.j) return false;
      if (cv < e.cv) return true;
      return false;
    }
    edge_list_elt(size_type ii, size_type jj, size_type ic = 0) : cv(ic)
    { i = std::min(ii, jj); j = std::max(ii, jj); }
    edge_list_elt() {}
  };

  typedef dal::dynamic_tree_sorted<edge_list_elt> edge_list;

  /* do not use that */
  void APIDECL mesh_edge_list_convex(pconvex_structure cvs,
                             std::vector<size_type> points_of_convex,
                             size_type cv_id, edge_list &el,
                             bool merge_convex);
  void APIDECL mesh_edge_list(const mesh_structure &m, edge_list &el,
                      bool merge_convex = true);



}  /* end of namespace bgeot.                                              */


#endif /* BGEOT_MESH_STRUCTURE_H__                                         */