CGAL 4.7 - Spatial Sorting: Spatial_sorting/small_example_delaunay_2.cpp

\( \newcommand{\E}{\mathrm{E}} \) \( \newcommand{\A}{\mathrm{A}} \) \( \newcommand{\R}{\mathrm{R}} \) \( \newcommand{\N}{\mathrm{N}} \) \( \newcommand{\Q}{\mathrm{Q}} \) \( \newcommand{\Z}{\mathrm{Z}} \) \( \def\ccSum #1#2#3{ \sum_{#1}^{#2}{#3} } \def\ccProd #1#2#3{ \sum_{#1}^{#2}{#3} }\)

CGAL 4.7 - Spatial Sorting

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Spatial_sorting/small_example_delaunay_2.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Delaunay_triangulation_2.h>
#include <CGAL/spatial_sort.h>
#include <CGAL/Timer.h>
#include <iostream>
#include <vector>
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Delaunay_triangulation_2<K> DT;
void compute_delaunay(std::vector<K::Point_2>::iterator it,
std::vector<K::Point_2>::iterator e){
DT dt;
DT::Face_handle hint;
for( ;it!=e; ++it) hint = dt.insert(*it, hint)->face();
}
int main ()
{ int size = 1000;
std::vector<K::Point_2> v;
v.reserve(size);
CGAL::Timer cost;
std::cout <<size<< " points on a parabola" << std::endl;
for (int i=0; i< size; ++i) {
double x= -size +i;
v.push_back( K::Point_2( x, x*x ));
}
cost.reset();cost.start();
std::cout << " Delaunay without spatial sort... "<< std::flush;
compute_delaunay(v.begin(),v.end());cost.stop();
std::cout << "done in "<<cost.time()<<" seconds." << std::endl;
cost.reset();cost.start();
std::cout << " Delaunay with Hilbert sort... " << std::flush;
CGAL::hilbert_sort(v.begin(),v.end());
compute_delaunay(v.begin(),v.end());cost.stop();
std::cout << "done in "<<cost.time()<<" seconds." << std::endl;
cost.reset();cost.start();
std::cout << " Delaunay with spatial sort... " << std::flush;
CGAL::spatial_sort(v.begin(),v.end());
compute_delaunay(v.begin(),v.end());cost.stop();
std::cout << "done in "<<cost.time()<<" seconds." << std::endl;
return 0;
}