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Diffstat (limited to 'src/Witness_complex/include/gudhi/Strong_witness_complex.h')
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diff --git a/src/Witness_complex/include/gudhi/Strong_witness_complex.h b/src/Witness_complex/include/gudhi/Strong_witness_complex.h new file mode 100644 index 00000000..c7b8c27b --- /dev/null +++ b/src/Witness_complex/include/gudhi/Strong_witness_complex.h @@ -0,0 +1,174 @@ +/* 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): Siargey Kachanovich + * + * Copyright (C) 2015 INRIA (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 STRONG_WITNESS_COMPLEX_H_ +#define STRONG_WITNESS_COMPLEX_H_ + +#include <utility> +#include <vector> +#include <list> +#include <limits> + +#include <gudhi/Active_witness/Active_witness.h> +#include <gudhi/Kd_tree_search.h> + +namespace gss = Gudhi::spatial_searching; + +namespace Gudhi { + +namespace witness_complex { + +/** + * \private + * \class Strong_witness_complex + * \brief Constructs strong witness complex for the given sets of witnesses and landmarks. + * \ingroup witness_complex + * + * \tparam Kernel_ requires a <a target="_blank" + * href="http://doc.cgal.org/latest/Kernel_d/classCGAL_1_1Epick__d.html">CGAL::Epick_d</a> class, which + * can be static if you know the ambiant dimension at compile-time, or dynamic if you don't. + * \tparam DimensionTag can be either <a target="_blank" + * href="http://doc.cgal.org/latest/Kernel_23/classCGAL_1_1Dimension__tag.html">Dimension_tag<d></a> + * if you know the intrinsic dimension at compile-time, + * or <a target="_blank" + * href="http://doc.cgal.org/latest/Kernel_23/classCGAL_1_1Dynamic__dimension__tag.html">CGAL::Dynamic_dimension_tag</a> + * if you don't. + */ +template< class Kernel_ > +class Strong_witness_complex { +private: + typedef Kernel_ K; + typedef typename K::Point_d Point_d; + typedef typename K::FT FT; + typedef std::vector<Point_d> Point_range; + typedef gss::Kd_tree_search<Kernel_, Point_range> Kd_tree; + typedef typename Kd_tree::INS_range Nearest_landmark_range; + typedef typename std::vector<Nearest_landmark_range> Nearest_landmark_table; + typedef typename Nearest_landmark_range::iterator Nearest_landmark_row_iterator; + + typedef std::vector< double > Point_t; + typedef std::vector< Point_t > Point_Vector; + + typedef FT Filtration_value; + + + typedef std::size_t Witness_id; + typedef typename Nearest_landmark_range::Point_with_transformed_distance Id_distance_pair; + typedef typename Id_distance_pair::first_type Landmark_id; + typedef Active_witness<Id_distance_pair, Nearest_landmark_range> ActiveWitness; + typedef std::list< ActiveWitness > ActiveWitnessList; + typedef std::vector< Landmark_id > typeVectorVertex; + typedef std::pair< typeVectorVertex, Filtration_value> typeSimplex; + + typedef Landmark_id Vertex_handle; + + private: + Point_range witnesses_, landmarks_; + Kd_tree landmark_tree_; + + public: + ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////// + /* @name Constructor + */ + + //@{ + + /** + * \brief Initializes member variables before constructing simplicial complex. + * \details Records landmarks from the range 'landmarks' into a + * table internally, as well as witnesses from the range 'witnesses'. + */ + template< typename LandmarkRange, + typename WitnessRange > + Strong_witness_complex(const LandmarkRange & landmarks, + const WitnessRange & witnesses) + : witnesses_(witnesses), landmarks_(landmarks), landmark_tree_(landmarks_) + { + } + + + /** \brief Returns the point corresponding to the given vertex. + */ + template <typename Vertex_handle> + Point_d get_point( Vertex_handle vertex ) const + { + return landmarks_[vertex]; + } + + /** \brief Outputs the strong witness complex of relaxation 'max_alpha_square' + * in a simplicial complex data structure. + * @param[out] complex Simplicial complex data structure, which is a model of + * SimplicialComplexForWitness concept. + * @param[in] max_alpha_square Maximal squared relaxation parameter. + * @param[in] limit_dimension Represents the maximal dimension of the simplicial complex + * (default value = no limit). + */ + template < typename SimplicialComplexForWitness > + bool create_complex(SimplicialComplexForWitness& complex, + FT max_alpha_square, + Landmark_id limit_dimension = std::numeric_limits<Landmark_id>::max()-1) + { + std::size_t nbL = landmarks_.size(); + Landmark_id complex_dim = 0; + if (complex.num_vertices() > 0) { + std::cerr << "Strong witness complex cannot create complex - complex is not empty.\n"; + return false; + } + if (max_alpha_square < 0) { + std::cerr << "Strong witness complex cannot create complex - squared relaxation parameter must be non-negative.\n"; + return false; + } + if (limit_dimension < 0) { + std::cerr << "Strong witness complex cannot create complex - limit dimension must be non-negative.\n"; + return false; + } + typeVectorVertex vv; + for (unsigned i = 0; i != nbL; ++i) { + // initial fill of 0-dimensional simplices + vv = {i}; + complex.insert_simplex(vv, Filtration_value(0.0)); + } + for (auto w: witnesses_) { + ActiveWitness aw(landmark_tree_.query_incremental_nearest_neighbors(w)); + typeVectorVertex simplex; + typename ActiveWitness::iterator aw_it = aw.begin(); + float lim_dist2 = aw.begin()->second + max_alpha_square; + while ((Landmark_id)simplex.size() <= limit_dimension + 1 && aw_it != aw.end() && aw_it->second < lim_dist2) { + simplex.push_back(aw_it->first); + complex.insert_simplex_and_subfaces(simplex, aw_it->second - aw.begin()->second); + aw_it++; + } + if ((Landmark_id)simplex.size() - 1 > complex_dim) + complex_dim = simplex.size() - 1; + } + complex.set_dimension(complex_dim); + return true; + } + + //@} +}; + +} // namespace witness_complex + +} // namespace Gudhi + +#endif |