From c524232f734de875d69e2f190f01a6c976024368 Mon Sep 17 00:00:00 2001 From: Gard Spreemann Date: Thu, 14 Jun 2018 20:39:01 +0200 Subject: GUDHI 2.2.0 as released by upstream in a tarball. --- example/Cech_complex/cech_complex_step_by_step.cpp | 166 +++++++++++++++++++++ 1 file changed, 166 insertions(+) create mode 100644 example/Cech_complex/cech_complex_step_by_step.cpp (limited to 'example/Cech_complex/cech_complex_step_by_step.cpp') diff --git a/example/Cech_complex/cech_complex_step_by_step.cpp b/example/Cech_complex/cech_complex_step_by_step.cpp new file mode 100644 index 00000000..d2dc8b65 --- /dev/null +++ b/example/Cech_complex/cech_complex_step_by_step.cpp @@ -0,0 +1,166 @@ +/* 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): Vincent Rouvreau + * + * Copyright (C) 2018 Inria + * + * 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 . + */ + +#include +#include +#include +#include + +#include + +#include + +#include +#include +#include // infinity +#include // for pair +#include + +// ---------------------------------------------------------------------------- +// rips_persistence_step_by_step is an example of each step that is required to +// build a Rips over a Simplex_tree. Please refer to rips_persistence to see +// how to do the same thing with the Rips_complex wrapper for less detailed +// steps. +// ---------------------------------------------------------------------------- + +// Types definition +using Simplex_tree = Gudhi::Simplex_tree<>; +using Simplex_handle = Simplex_tree::Simplex_handle; +using Filtration_value = Simplex_tree::Filtration_value; +using Point = std::vector; +using Points_off_reader = Gudhi::Points_off_reader; +using Proximity_graph = Gudhi::Proximity_graph; + +class Cech_blocker { + private: + using Point_cloud = std::vector; + using Point_iterator = Point_cloud::const_iterator; + using Coordinate_iterator = Point::const_iterator; + using Min_sphere = Gudhi::Miniball::Miniball>; + + public: + bool operator()(Simplex_handle sh) { + std::vector points; + for (auto vertex : simplex_tree_.simplex_vertex_range(sh)) { + points.push_back(point_cloud_[vertex]); +#ifdef DEBUG_TRACES + std::cout << "#(" << vertex << ")#"; +#endif // DEBUG_TRACES + } + Filtration_value radius = Gudhi::Minimal_enclosing_ball_radius()(points); +#ifdef DEBUG_TRACES + std::cout << "radius = " << radius << " - " << (radius > max_radius_) << std::endl; +#endif // DEBUG_TRACES + simplex_tree_.assign_filtration(sh, radius); + return (radius > max_radius_); + } + Cech_blocker(Simplex_tree& simplex_tree, Filtration_value max_radius, const std::vector& point_cloud) + : simplex_tree_(simplex_tree), max_radius_(max_radius), point_cloud_(point_cloud) { + dimension_ = point_cloud_[0].size(); + } + + private: + Simplex_tree simplex_tree_; + Filtration_value max_radius_; + std::vector point_cloud_; + int dimension_; +}; + +void program_options(int argc, char* argv[], std::string& off_file_points, Filtration_value& max_radius, int& dim_max); + +int main(int argc, char* argv[]) { + std::string off_file_points; + Filtration_value max_radius; + int dim_max; + + program_options(argc, argv, off_file_points, max_radius, dim_max); + + // Extract the points from the file filepoints + Points_off_reader off_reader(off_file_points); + + // Compute the proximity graph of the points + Proximity_graph prox_graph = Gudhi::compute_proximity_graph(off_reader.get_point_cloud(), max_radius, + Gudhi::Minimal_enclosing_ball_radius()); + + // Construct the Rips complex in a Simplex Tree + Simplex_tree st; + // insert the proximity graph in the simplex tree + st.insert_graph(prox_graph); + // expand the graph until dimension dim_max + st.expansion_with_blockers(dim_max, Cech_blocker(st, max_radius, off_reader.get_point_cloud())); + + std::cout << "The complex contains " << st.num_simplices() << " simplices \n"; + std::cout << " and has dimension " << st.dimension() << " \n"; + + // Sort the simplices in the order of the filtration + st.initialize_filtration(); + +#if DEBUG_TRACES + std::cout << "********************************************************************\n"; + std::cout << "* The complex contains " << st.num_simplices() << " simplices - dimension=" << st.dimension() << "\n"; + std::cout << "* Iterator on Simplices in the filtration, with [filtration value]:\n"; + for (auto f_simplex : st.filtration_simplex_range()) { + std::cout << " " + << "[" << st.filtration(f_simplex) << "] "; + for (auto vertex : st.simplex_vertex_range(f_simplex)) { + std::cout << static_cast(vertex) << " "; + } + std::cout << std::endl; + } +#endif // DEBUG_TRACES + + return 0; +} + +void program_options(int argc, char* argv[], std::string& off_file_points, Filtration_value& max_radius, int& dim_max) { + namespace po = boost::program_options; + po::options_description hidden("Hidden options"); + hidden.add_options()("input-file", po::value(&off_file_points), + "Name of an OFF file containing a point set.\n"); + + po::options_description visible("Allowed options", 100); + visible.add_options()("help,h", "produce help message")( + "max-radius,r", + po::value(&max_radius)->default_value(std::numeric_limits::infinity()), + "Maximal length of an edge for the Rips complex construction.")( + "cpx-dimension,d", po::value(&dim_max)->default_value(1), + "Maximal dimension of the Rips complex we want to compute."); + + po::positional_options_description pos; + pos.add("input-file", 1); + + po::options_description all; + all.add(visible).add(hidden); + + po::variables_map vm; + po::store(po::command_line_parser(argc, argv).options(all).positional(pos).run(), vm); + po::notify(vm); + + if (vm.count("help") || !vm.count("input-file")) { + std::cout << std::endl; + std::cout << "Construct a Cech complex defined on a set of input points.\n \n"; + + std::cout << "Usage: " << argv[0] << " [options] input-file" << std::endl << std::endl; + std::cout << visible << std::endl; + std::abort(); + } +} -- cgit v1.2.3