mirror of https://github.com/CGAL/cgal
85 lines
3.1 KiB
C++
85 lines
3.1 KiB
C++
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
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#include <CGAL/natural_neighbor_coordinates_2.h>
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#include <CGAL/Interpolation_gradient_fitting_traits_2.h>
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#include <CGAL/sibson_gradient_fitting.h>
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#include <CGAL/interpolation_functions.h>
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#include <CGAL/Regular_triangulation_2.h>
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#include <iostream>
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#include <iterator>
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#include <map>
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#include <utility>
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#include <vector>
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typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
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typedef CGAL::Regular_triangulation_2<K> Regular_triangulation;
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typedef CGAL::Interpolation_gradient_fitting_traits_2<K> Traits;
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typedef K::FT Coord_type;
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typedef K::Weighted_point_2 Point;
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struct Less
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{
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bool operator()(const Point& p, const Point& q) const {
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return K::Less_xy_2()(p.point(), q.point());
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}
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};
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typedef std::map<Point, Coord_type, Less> Point_value_map ;
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typedef std::map<Point, K::Vector_2 , Less> Point_vector_map;
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int main()
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{
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Regular_triangulation T;
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Point_value_map value_function;
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Point_vector_map gradient_function;
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//parameters for spherical function:
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Coord_type a(0.25), bx(1.3), by(-0.7), c(0.2);
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for (int y=0; y<4; y++) {
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for (int x=0; x<4; x++) {
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Point p(x,y);
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T.insert(p);
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value_function.insert(std::make_pair(p, a + bx*x + by*y + c*(x*x+y*y)));
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}
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}
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sibson_gradient_fitting_rn_2(T,
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std::inserter(gradient_function, gradient_function.begin()),
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CGAL::Data_access<Point_value_map>(value_function),
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Traits());
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for(const Point_vector_map::value_type& pv : gradient_function) {
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std::cout << pv.first << " " << pv.second << std::endl;
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}
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//coordinate computation
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Point p(1.6, 1.4);
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std::vector<std::pair<Point, Coord_type> > coords;
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Coord_type norm = CGAL::regular_neighbor_coordinates_2(T, p, std::back_inserter(coords)).second;
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//Sibson interpolant: version without sqrt:
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std::pair<Coord_type, bool> res = CGAL::sibson_c1_interpolation_square(coords.begin(),
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coords.end(),
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norm,
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p,
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CGAL::Data_access<Point_value_map>(value_function),
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CGAL::Data_access<Point_vector_map>(gradient_function),
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Traits());
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if(res.second)
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std::cout << "Tested interpolation on " << p
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<< " interpolation: " << res.first << " exact: "
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<< a + bx*p.x() + by*p.y()+ c*(p.x()*p.x()+p.y()*p.y())
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<< std::endl;
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else
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std::cout << "C^1 Interpolation not successful." << std::endl
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<< " not all gradients are provided." << std::endl
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<< " You may resort to linear interpolation." << std::endl;
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return 0;
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}
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