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Diffstat (limited to 'GudhUI/utils/Edge_contractor.h')
-rw-r--r-- | GudhUI/utils/Edge_contractor.h | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/GudhUI/utils/Edge_contractor.h b/GudhUI/utils/Edge_contractor.h new file mode 100644 index 00000000..45079a40 --- /dev/null +++ b/GudhUI/utils/Edge_contractor.h @@ -0,0 +1,97 @@ +/* This file is part of the Gudhi Library. The Gudhi library + * (Geometric Understanding in Higher Dimensions) is a generic C++ + * library for computational topology. + * + * Author(s): David Salinas + * + * Copyright (C) 2014 INRIA Sophia Antipolis-Mediterranee (France) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#ifndef UTILS_EDGE_CONTRACTOR_H_ +#define UTILS_EDGE_CONTRACTOR_H_ + + +#include <gudhi/Skeleton_blocker_contractor.h> +#include <gudhi/Contraction/Edge_profile.h> +#include <gudhi/Contraction/policies/Cost_policy.h> + +#include <vector> + +/** + * Iteratively puts every vertex at the center of its neighbors + */ +template<typename SkBlComplex> class Edge_contractor { + private: + SkBlComplex& complex_; + unsigned num_contractions_; + + /** + * @brief return a cost corresponding to the squared length of the edge + */ + template< typename EdgeProfile> class Length_cost : public contraction::Cost_policy<EdgeProfile> { + public: + typedef typename contraction::Cost_policy<EdgeProfile>::Cost_type Cost_type; + typedef typename EdgeProfile::Point Point; + + Cost_type operator()(const EdgeProfile& profile, const boost::optional<Point>& placement) const override { + Cost_type res; + if (!placement) + return res; + return Geometry_trait::Squared_distance_d()(profile.p0(), profile.p1()); // not working?? + } + }; + + /** + * @brief return a cost corresponding to the squared length of the edge + */ + template< typename EdgeProfile> class Middle_placement : public contraction::Placement_policy<EdgeProfile> { + public: + typedef typename contraction::Placement_policy<EdgeProfile>::Placement_type Placement_type; + typedef typename EdgeProfile::Point Point; + + Placement_type operator()(const EdgeProfile& profile) const override { + std::vector<double> mid_coords(profile.p0().dimension(), 0); + for (size_t i = 0; i < profile.p0().dimension(); ++i) { + mid_coords[i] = (profile.p0()[i] + profile.p1()[i]) / 2.; + } + return Point(profile.p0().dimension(), mid_coords.begin(), mid_coords.end()); + } + }; + + public: + typedef typename SkBlComplex::Vertex_handle Vertex_handle; + typedef typename SkBlComplex::Edge_handle Edge_handle; + + /** + * @brief Modify complex to be the expansion of the k-nearest neighbor + * symetric graph. + */ + Edge_contractor(SkBlComplex& complex, unsigned num_contractions) : + complex_(complex), num_contractions_(num_contractions) { + typedef typename contraction::Edge_profile<Complex> Profile; + num_contractions = (std::min)(static_cast<int>(num_contractions), static_cast<int>(complex_.num_vertices() - 1)); + typedef typename contraction::Skeleton_blocker_contractor<Complex> Contractor; + Contractor contractor(complex_, + new Length_cost<contraction::Edge_profile < Complex >> (), + new Middle_placement<contraction::Edge_profile < Complex >> (), + contraction::make_link_valid_contraction<Profile>(), + contraction::make_remove_popable_blockers_visitor<Profile>()); + contractor.contract_edges(num_contractions); + } +}; + +#endif // UTILS_EDGE_CONTRACTOR_H_ |