\( \newcommand{\E}{\mathrm{E}} \) \( \newcommand{\A}{\mathrm{A}} \) \( \newcommand{\R}{\mathrm{R}} \) \( \newcommand{\N}{\mathrm{N}} \) \( \newcommand{\Q}{\mathrm{Q}} \) \( \newcommand{\Z}{\mathrm{Z}} \) \( \def\ccSum #1#2#3{ \sum_{#1}^{#2}{#3} } \def\ccProd #1#2#3{ \sum_{#1}^{#2}{#3} }\)
CGAL 4.11.2 - Point Set Processing
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Point_set_processing_3/scale_estimation_example.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/IO/read_xyz_points.h>
#include <CGAL/estimate_scale.h>
#include <CGAL/jet_smooth_point_set.h>
#include <CGAL/grid_simplify_point_set.h>
#include <CGAL/Timer.h>
#include <CGAL/Memory_sizer.h>
#include <vector>
#include <fstream>
#include <boost/tuple/tuple.hpp>
// Concurrency
#ifdef CGAL_LINKED_WITH_TBB
typedef CGAL::Parallel_tag Concurrency_tag;
#else
typedef CGAL::Sequential_tag Concurrency_tag;
#endif
// Types
typedef Kernel::FT FT;
typedef Kernel::Point_3 Point_3;
int main (int argc, char** argv)
{
const char* fname = (argc>1)?argv[1]:"data/sphere_20k.xyz";
CGAL::Timer task_timer;
std::vector<Point_3> points;
std::ifstream stream(fname);
// read input
if (!(stream
&& CGAL::read_xyz_points(stream, std::back_inserter(points))))
{
std::cerr << "Error: can't read input file" << std::endl;
return EXIT_FAILURE;
}
// estimate k scale
task_timer.start();
std::size_t k_scale = CGAL::estimate_global_k_neighbor_scale (points.begin(), points.end());
task_timer.stop();
// Example: use estimated k as scale for jet smoothing
CGAL::jet_smooth_point_set<Concurrency_tag>
(points.begin(), points.end(),
static_cast<unsigned int>(k_scale));
// estimate range scale
task_timer.start();
FT range_scale = CGAL::estimate_global_range_scale (points.begin(), points.end());
task_timer.stop();
// Example: use estimated range for grid simplification
points.erase (CGAL::grid_simplify_point_set (points.begin(), points.end(), range_scale),
points.end());
// print some informations on runtime
std::size_t memory = CGAL::Memory_sizer().virtual_size();
double time = task_timer.time();
std::cout << "Scales computed in " << time << " second(s) using "
<< (memory>>20) << " MiB of memory:" << std::endl;
std::cout << " * Global K scale: " << k_scale << std::endl;
std::cout << " * Global range scale: " << range_scale << std::endl;
return EXIT_SUCCESS;
}