example_sparse_rips.cpp

#include <gudhi/Sparse_rips_complex.h>
#include <gudhi/Simplex_tree.h>
#include <gudhi/distance_functions.h>
 
#include <iostream>
#include <vector>
 
int main() {
  using Point = std::vector<double>;
  using Simplex_tree = Gudhi::Simplex_tree<Gudhi::Simplex_tree_options_fast_persistence>;
  using Filtration_value = Simplex_tree::Filtration_value;
  using Sparse_rips = Gudhi::rips_complex::Sparse_rips_complex<Filtration_value>;
 
  Point points[] = {{1.0, 1.0}, {7.0, 0.0}, {4.0, 6.0}, {9.0, 6.0}, {0.0, 14.0}, {2.0, 19.0}, {9.0, 17.0}};
 
  // ----------------------------------------------------------------------------
  // Init from Euclidean points
  // ----------------------------------------------------------------------------
  double epsilon = 2;  // very rough, no guarantees
  Sparse_rips sparse_rips(points, Gudhi::Euclidean_distance(), epsilon);
 
  Simplex_tree stree;
  sparse_rips.create_complex(stree, 10);
 
  // ----------------------------------------------------------------------------
  // Display information about the complex
  // ----------------------------------------------------------------------------
  std::clog << "Sparse Rips complex is of dimension " << stree.dimension() << " - " << stree.num_simplices()
            << " simplices - " << stree.num_vertices() << " vertices." << std::endl;
}