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/* 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
*
* 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 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>;
/**
* \brief Rock age method of reading off file
*
*/
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();
}
/**
* \brief Customized version of read_points
* which takes into account a possible nbP first line
*
*/
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();
}
/** \brief Generate points on a grid in a cube of side 2
* having {+-1}^D as vertices and insert them in W.
* The grid has "width" points on each side.
* If torus is true then it is supposed that the cube represents
* a flat torus, hence the opposite borders are associated.
* The points on border in this case are not placed twice.
*/
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);
}
}
/** \brief Generate nbP points uniformly in a cube of side 2
* having {+-1}^dim as its vertices and insert them in W.
*/
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++);
}
}
/** \brief Generate nbP points uniformly on a (dim-1)-sphere
* and insert them in W.
*/
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++);
}
/** \brief Generate nbP points on a (flat) d-torus embedded in R^{2d}
*
*/
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_
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