Edge_contractor.h
1 /* This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT.
2  * See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details.
3  * Author(s): David Salinas
4  *
5  * Copyright (C) 2014 Inria
6  *
7  * Modification(s):
8  * - YYYY/MM Author: Description of the modification
9  */
10 
11 #ifndef UTILS_EDGE_CONTRACTOR_H_
12 #define UTILS_EDGE_CONTRACTOR_H_
13 
14 
15 #include <gudhi/Skeleton_blocker_contractor.h>
16 #include <gudhi/Contraction/Edge_profile.h>
17 #include <gudhi/Contraction/policies/Cost_policy.h>
18 
19 #include <vector>
20 
24 template<typename SkBlComplex> class Edge_contractor {
25  private:
26  SkBlComplex& complex_;
27  unsigned num_contractions_;
28 
32  template< typename EdgeProfile> class Length_cost : public contraction::Cost_policy<EdgeProfile> {
33  public:
34  typedef typename contraction::Cost_policy<EdgeProfile>::Cost_type Cost_type;
35  typedef typename EdgeProfile::Point Point;
36 
37  Cost_type operator()(const EdgeProfile& profile, const boost::optional<Point>& placement) const override {
38  Cost_type res;
39  if (!placement)
40  return res;
41  return Geometry_trait::Squared_distance_d()(profile.p0(), profile.p1()); // not working??
42  }
43  };
44 
48  template< typename EdgeProfile> class Middle_placement : public contraction::Placement_policy<EdgeProfile> {
49  public:
50  typedef typename contraction::Placement_policy<EdgeProfile>::Placement_type Placement_type;
51  typedef typename EdgeProfile::Point Point;
52 
53  Placement_type operator()(const EdgeProfile& profile) const override {
54  std::vector<double> mid_coords(profile.p0().dimension(), 0);
55  for (int i = 0; i < profile.p0().dimension(); ++i) {
56  mid_coords[i] = (profile.p0()[i] + profile.p1()[i]) / 2.;
57  }
58  return Point(profile.p0().dimension(), mid_coords.begin(), mid_coords.end());
59  }
60  };
61 
62  public:
63  typedef typename SkBlComplex::Vertex_handle Vertex_handle;
64  typedef typename SkBlComplex::Edge_handle Edge_handle;
65 
70  Edge_contractor(SkBlComplex& complex, unsigned num_contractions) :
71  complex_(complex), num_contractions_(num_contractions) {
72  typedef typename contraction::Edge_profile<Complex> Profile;
73  num_contractions = (std::min)(static_cast<int>(num_contractions), static_cast<int>(complex_.num_vertices() - 1));
74  typedef typename contraction::Skeleton_blocker_contractor<Complex> Contractor;
75  Contractor contractor(complex_,
76  new Length_cost<contraction::Edge_profile < Complex >> (),
77  new Middle_placement<contraction::Edge_profile < Complex >> (),
78  contraction::make_link_valid_contraction<Profile>(),
79  contraction::make_remove_popable_blockers_visitor<Profile>());
80  contractor.contract_edges(num_contractions);
81  }
82 };
83 
84 #endif // UTILS_EDGE_CONTRACTOR_H_
Definition: Edge_contractor.h:24
Edge_contractor(SkBlComplex &complex, unsigned num_contractions)
Modify complex to be the expansion of the k-nearest neighbor symetric graph.
Definition: Edge_contractor.h:70
GUDHIdev  Version 3.5.0  - C++ library for Topological Data Analysis (TDA) and Higher Dimensional Geometry Understanding.  - Copyright : MIT Generated on Sun May 1 2022 09:19:32 for GUDHIdev by Doxygen 1.9.1