periodic_cubical_complex_persistence.cpp

/*    This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT.
 *    See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details.
 *    Author(s):       Pawel Dlotko
 *
 *    Copyright (C) 2015 Inria
 *
 *    Modification(s):
 *      - YYYY/MM Author: Description of the modification
 */
 
#include <gudhi/reader_utils.h>
#include <gudhi/Bitmap_cubical_complex.h>
#include <gudhi/Bitmap_cubical_complex_periodic_boundary_conditions_base.h>
#include <gudhi/Persistent_cohomology.h>
 
// standard stuff
#include <iostream>
#include <sstream>
#include <vector>
#include <string>
 
int main(int argc, char** argv) {
  std::clog
      << "This program computes persistent homology, by using "
      << "Bitmap_cubical_complex_periodic_boundary_conditions class, of cubical complexes provided in text files in "
      << "Perseus style (the only numbered in the first line is a dimension D of a bitmap. In the lines I between 2 "
      << "and D+1 there are numbers of top dimensional cells in the direction I. Let N denote product of the numbers "
      << "in the lines between 2 and D. In the lines D+2 to D+2+N there are filtrations of top dimensional cells. We "
      << "assume that the cells are in the lexicographical order. See CubicalOneSphere.txt or CubicalTwoSphere.txt for"
      << " example.\n"
      << std::endl;
 
  if (argc != 2) {
    std::cerr << "Wrong number of parameters. Please provide the name of a file with a Perseus style bitmap at "
              << "the input. The program will now terminate.\n";
    return 1;
  }
 
  typedef Gudhi::cubical_complex::Bitmap_cubical_complex_periodic_boundary_conditions_base<double> Bitmap_base;
  typedef Gudhi::cubical_complex::Bitmap_cubical_complex<Bitmap_base> Bitmap_cubical_complex;
 
  Bitmap_cubical_complex b(argv[1]);
 
  typedef Gudhi::persistent_cohomology::Field_Zp Field_Zp;
  typedef Gudhi::persistent_cohomology::Persistent_cohomology<Bitmap_cubical_complex, Field_Zp> Persistent_cohomology;
  // Compute the persistence diagram of the complex
  Persistent_cohomology pcoh(b, true);
 
  int p = 11;
  double min_persistence = 0;
  pcoh.init_coefficients(p);  // initializes the coefficient field for homology
  pcoh.compute_persistent_cohomology(min_persistence);
 
  std::string output_file_name(argv[1]);
  output_file_name += "_persistence";
 
  std::size_t last_in_path = output_file_name.find_last_of("/\\");
 
  if (last_in_path != std::string::npos) {
    output_file_name = output_file_name.substr(last_in_path + 1);
  }
 
  std::ofstream out(output_file_name.c_str());
  pcoh.output_diagram(out);
  out.close();
 
  std::clog << "Result in file: " << output_file_name << "\n";
 
  return 0;
}