generators.h

/*    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):       Siargey Kachanovich
 *
 *    Copyright (C) 2015 Inria
 *
 *    Modification(s):
 *      - YYYY/MM Author: Description of the modification
 */
 
#ifndef GENERATORS_H_
#define GENERATORS_H_
 
#include <CGAL/Epick_d.h>
#include <CGAL/point_generators_d.h>
#include <CGAL/Random.h>
 
#include <fstream>
#include <string>
#include <vector>
#include <cmath>
 
using K = CGAL::Epick_d<CGAL::Dynamic_dimension_tag>;
using FT = K::FT;
using Point_d = K::Point_d;
using Point_Vector = std::vector<Point_d>;
using Random_cube_iterator = CGAL::Random_points_in_cube_d<Point_d>;
using Random_point_iterator = CGAL::Random_points_in_ball_d<Point_d>;
 
inline void
off_reader_cust(std::string file_name, std::vector<Point_d> & points) {
  std::ifstream in_file(file_name.c_str(), std::ios::in);
  if (!in_file.is_open()) {
    std::cerr << "Unable to open file " << file_name << std::endl;
    return;
  }
  std::string line;
  double x;
  // Line OFF. No need in it
  if (!getline(in_file, line)) {
    std::cerr << "No line OFF\n";
    return;
  }
  // Line with 3 numbers. No need
  if (!getline(in_file, line)) {
    std::cerr << "No line with 3 numbers\n";
    return;
  }
  // Reading points
  while (getline(in_file, line)) {
    std::vector< double > point;
    std::istringstream iss(line);
    while (iss >> x) {
      point.push_back(x);
    }
    points.push_back(Point_d(point));
  }
  in_file.close();
}
 
inline void
read_points_cust(std::string file_name, Point_Vector & points) {
  std::ifstream in_file(file_name.c_str(), std::ios::in);
  if (!in_file.is_open()) {
    std::cerr << "Unable to open file " << file_name << std::endl;
    return;
  }
  std::string line;
  double x;
  while (getline(in_file, line)) {
    std::vector< double > point;
    std::istringstream iss(line);
    while (iss >> x) {
      point.push_back(x);
    }
    Point_d p(point.begin(), point.end());
    if (point.size() != 1)
      points.push_back(p);
  }
  in_file.close();
}
 
void generate_points_grid(Point_Vector& W, int width, int D, bool torus) {
  int nb_points = 1;
  for (int i = 0; i < D; ++i)
    nb_points *= width;
  for (int i = 0; i < nb_points; ++i) {
    std::vector<double> point;
    int cell_i = i;
    for (int l = 0; l < D; ++l) {
      if (torus)
        point.push_back(-1 + (2.0 / (width - 1))*(cell_i % width));
      else
        point.push_back(-1 + (2.0 / width)*(cell_i % width));
      // attention: the bottom and the right are covered too!
      cell_i /= width;
    }
    W.push_back(point);
  }
}
 
void generate_points_random_box(Point_Vector& W, int nbP, int dim) {
  Random_cube_iterator rp(dim, 1.0);
  for (int i = 0; i < nbP; i++) {
    W.push_back(*rp++);
  }
}
 
void generate_points_sphere(Point_Vector& W, int nbP, int dim) {
  CGAL::Random_points_on_sphere_d<Point_d> rp(dim, 1);
  for (int i = 0; i < nbP; i++)
    W.push_back(*rp++);
}
 
void generate_points_torus(Point_Vector& W, int nbP, int dim) {
  CGAL::Random rand;
  const double pi = std::acos(-1);
  for (int i = 0; i < nbP; i++) {
    std::vector<FT> point;
    for (int j = 0; j < dim; j++) {
      double alpha = rand.uniform_real(static_cast<double>(0), 2*pi);
      point.push_back(sin(alpha));
      point.push_back(cos(alpha));
    }
    W.push_back(Point_d(point));
  }
}
 
#endif  // GENERATORS_H_