bgeot_convex.h

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/* -*- c++ -*- (enables emacs c++ mode) */
/*===========================================================================
 
 Copyright (C) 1999-2026 Yves Renard
 
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/**@file bgeot_convex.h
   @author  Yves Renard <Yves.Renard@insa-lyon.fr>
   @date December 20, 1999.
   @brief Convex objects (structure + vertices)
*/
 
#ifndef BGEOT_CONVEX_H__
#define BGEOT_CONVEX_H__
 
#include "bgeot_convex_structure.h"
 
namespace bgeot {
 
  /** @defgroup convexes Convexes */
  /** @addtogroup convexes */
  /*@{*/
 
  /// generic definition of a convex ( bgeot::convex_structure + vertices coordinates )
  template<class PT, class PT_TAB = std::vector<PT> > class convex {
  public :
    
    typedef PT point_type;
    typedef PT_TAB point_tab_type;
    typedef typename PT_TAB::size_type size_type;
    
    typedef gmm::tab_ref_index_ref< typename PT_TAB::const_iterator,
      convex_ind_ct::const_iterator> ref_convex_pt_ct;
    
    typedef gmm::tab_ref_index_ref< typename PT_TAB::const_iterator,
      ref_convex_ind_ct::const_iterator> dref_convex_pt_ct;
    
  protected :
    
    pconvex_structure cvs;
    PT_TAB pts;
    
  public :
    
    ref_convex_pt_ct points_of_face(short_type i) const {
      return ref_convex_pt_ct(pts.begin(), cvs->ind_points_of_face(i).begin(),
                              cvs->ind_points_of_face(i).end());
    }
    
    /** Return "direct" points. These are the subset of points than can be
        used to build a direct vector basis. (rarely used)
    */
    ref_convex_pt_ct dir_points() const {
      return ref_convex_pt_ct(pts.begin(), cvs->ind_dir_points().begin(),
                              cvs->ind_dir_points().end());
    }
    /** Direct points for a given face.
        @param i the face number.
    */
    dref_convex_pt_ct dir_points_of_face(short_type i) const {
      return dref_convex_pt_ct(pts.begin(),
                               cvs->ind_dir_points_of_face(i).begin(),
                               cvs->ind_dir_points_of_face(i).end());
    }
    pconvex_structure structure() const { return cvs; }
    pconvex_structure &structure() { return cvs; }
    const PT_TAB &points() const { return pts; }
    PT_TAB &points() { return pts; }
    short_type nb_points() const { return cvs->nb_points(); }
    
    //void translate(const typename PT::vector_type &v);
    //template <class CONT> void base_of_orthogonal(CONT &tab);
    convex() { }
    /** Build a convex object.
        @param c the convex structure.
        @param t the points array.
    */
    convex(pconvex_structure c, const PT_TAB &t) : cvs(c), pts(t) {}
    convex(pconvex_structure c) : cvs(c) {}
  };
  /*@}*/
  /*template<class PT, class PT_TAB>
    void convex<PT, PT_TAB>::translate(const typename PT::vector_type &v) {
    typename PT_TAB::iterator b = pts.begin(), e = pts.end();
    for ( ; b != e ; ++b) *b += v;
  }
  */
  /*  
  template<class PT, class PT_TAB> template<class CONT>
    void convex<PT, PT_TAB>::base_of_orthogonal(CONT &tab)
  { // programmation a revoir.
    int N = (points())[0].size();
    pconvex_structure cv = structure();
    int n = cv->dim();
    dal::dynamic_array<typename PT::vector_type> vect_;
    vsvector<double> A(N), B(N);
    ref_convex_ind_ct dptf = cv->ind_dir_points_of_face(f);
    int can_b = 0;
    
    for (int i = 0; i < n-1; i++) {
      vect_[i]  = (points())[dptf[i+1]]; vect_[i] -= (points())[dptf[0]];
      
      for (j = 0; j < i; j++)
        A[j] = vect_sp(vect_[i], vect_[j]);
      for (j = 0; j < i; j++)
        { B = vect_[j]; B *= A[j]; vect_[i] -= B; }
      vect_[i] /= vect_norm2(vect_[i]);
    }
    
    for (int i = n; i < N; i++) {
      vect_[i] = vect_[0];
      vect_random(vect_[i]);
      for (j = 0; j < i; j++)
        A[j] = vect_sp(vect_[i], vect_[j]);
      for (j = 0; j < i; j++)
        { B = vect_[j]; B *= A[j]; vect_[i] -= B; }
      
      if (vect_norm2(vect_[i]) < 1.0E-4 )
        i--;
      else
        vect_[i] /= vect_norm2(vect_[i]);
    }
    for (int i = n; i < N; i++) tab[i-n] = vect_[i];
  }
  */
 
  template<class PT, class PT_TAB>
    std::ostream &operator <<(std::ostream &o, const convex<PT, PT_TAB> &cv)
  {
    o << *(cv.structure());
    o << " points : ";
    for (size_type i = 0; i < cv.nb_points(); ++i) o << cv.points()[i] << " ";
    o << endl;
    return o;
  }
 
  /* ********************************************************************** */
  /* Unstabilized part.                                                     */
  /* ********************************************************************** */
 
  template<class PT, class PT_TAB>
    convex<PT, PT_TAB> simplex(const PT_TAB &t, int nc)
  { return convex<PT, PT_TAB>(simplex_structure(nc), t); }
 
 
  template<class PT, class PT_TAB1, class PT_TAB2>
    convex<PT> convex_product(const convex<PT, PT_TAB1> &cv1,
                              const convex<PT, PT_TAB2> &cv2)
  { // optimisable
    typename convex<PT>::point_tab_type tab;
    tab.resize(cv1.nb_points() * cv2.nb_points());
    size_type i,j,k;
    for (i = 0, k = 0; i < cv1.nb_points(); ++i)
      for (j = 0; j < cv2.nb_points(); ++j, ++k)
        { tab[k] = (cv1.points())[i]; tab[k] += (cv2.points())[j]; }
    return convex<PT>(
             convex_product_structure(cv1.structure(), cv2.structure()), tab);
  }
 
  struct special_convex_structure_key_ : virtual public dal::static_stored_object_key {
    pconvex_structure p;
    bool compare(const static_stored_object_key &oo) const override {
      auto &o = dynamic_cast<const special_convex_structure_key_ &>(oo);
      return p < o.p;
    }
    bool equal(const static_stored_object_key &oo) const override {
      auto &o = dynamic_cast<const special_convex_structure_key_ &>(oo);
      if (p == o.p) return true;
 
      auto pkey = dal::key_of_stored_object(p);
      auto poo_key = dal::key_of_stored_object(o.p);
      return *pkey == *poo_key;
    }
    special_convex_structure_key_(pconvex_structure pp) : p(pp) {}
  };
 
  template<class PT, class PT_TAB1, class PT_TAB2>
    convex<PT> convex_direct_product(const convex<PT, PT_TAB1> &cv1,
                                     const convex<PT, PT_TAB2> &cv2) {
    if (cv1.nb_points() == 0 || cv2.nb_points() == 0)
      throw std::invalid_argument(
                     "convex_direct_product : null convex product");
    
    if (!dal::exists_stored_object(cv1.structure())) {
      dal::pstatic_stored_object_key
        pcs = std::make_shared<special_convex_structure_key_>(cv1.structure());
      dal::add_stored_object(pcs, cv1.structure(),
                             dal::AUTODELETE_STATIC_OBJECT);
    }
    if (!dal::exists_stored_object(cv2.structure())) {
      dal::pstatic_stored_object_key
        pcs = std::make_shared<special_convex_structure_key_>(cv2.structure());
      dal::add_stored_object(pcs, cv2.structure(),
                             dal::AUTODELETE_STATIC_OBJECT);
    }
    convex<PT> r(convex_product_structure(cv1.structure(), cv2.structure()));
    r.points().resize(r.nb_points());
    std::fill(r.points().begin(), r.points().end(), PT(r.structure()->dim()));
    dim_type dim1 = cv1.structure()->dim();
    typename PT_TAB1::const_iterator it1, it1e = cv1.points().end();
    typename PT_TAB2::const_iterator it2, it2e = cv2.points().end();
    typename convex<PT>::point_tab_type::iterator it = r.points().begin();
    for (it2 = cv2.points().begin(); it2 != it2e; ++it2)
      for (it1 = cv1.points().begin() ; it1 != it1e; ++it1, ++it)
      {
        std::copy((*it1).begin(), (*it1).end(), (*it).begin());
        std::copy((*it2).begin(), (*it2).end(), (*it).begin()+dim1);
      }
    return r;
  }
 
  template<class PT, class PT_TAB>
    convex<PT> convex_multiply(const convex<PT, PT_TAB> &cv, dim_type n)
  {
    if (cv.nb_points() == 0 || n == 0)
      throw std::invalid_argument(
                     "convex_multiply : null convex product");
    convex<PT> r(multiply_convex_structure(cv.structure(), n));
    r.points().resize(r.nb_points());
    std::fill(r.points().begin(), r.points().end(), PT(r.structure()->dim()));
    dim_type dim1 = cv.structure()->dim();
    typename convex<PT>::point_tab_type::iterator it = r.points().begin();
    typename PT_TAB::const_iterator it1  = cv.points().begin(), it2,
                                    it1e = cv.points().end();
    for (dim_type k = 0; k < n; ++k)
      for (it2 = it1; it2 != it1e; ++it2) *it++ = *it2;
    return r;
  }
 
}  /* end of namespace bgeot.                                             */
 
 
#endif /* BGEOT_CONVEX_H__                                                */