int main()
{
Delaunay_triangulation T;
Point_value_map value_function;
Point_vector_map gradient_function;
//parameters for spherical function:
Coord_type a(0.25), bx(1.3), by(-0.7), c(0.2);
for (int y=0; y<4; y++) {
for (int x=0; x<4; x++) {
K::Point_2 p(x,y);
T.insert(p);
value_function.insert(std::make_pair(p,a + bx* x+ by*y + c*(x*x+y*y)));
}
}
sibson_gradient_fitting_nn_2(T, std::inserter(gradient_function,
gradient_function.begin()),
CGAL:: Data_access<Point_value_map>(value_function),
Traits());
for(Point_vector_map::iterator it = gradient_function.begin(); it != gradient_function.end(); ++it)
{
std::cout << it->first << " " << it->second << std::endl;
}
// coordinate computation
K::Point_2 p(1.6, 1.4);
std::vector< std::pair< Point, Coord_type > > coords;
Coord_type norm = CGAL::natural_neighbor_coordinates_2(T, p, std::back_inserter(coords)).second;
//Sibson interpolant: version without sqrt:
std::pair<Coord_type, bool> res =
CGAL::sibson_c1_interpolation_square(coords.begin(),
coords.end(), norm, p,
CGAL::Data_access<Point_value_map>(value_function),
CGAL::Data_access<Point_vector_map>(gradient_function),
Traits());
if(res.second)
std::cout << "Tested interpolation on " << p
<< " interpolation: " << res.first << " exact: "
<< a + bx*p.x() + by*p.y() + c*(p.x()*p.x()+p.y()*p.y())
<< std::endl;
else
std::cout << "C^1 Interpolation not successful." << std::endl
<< " not all gradients are provided." << std::endl
<< " You may resort to linear interpolation." << std::endl;
return EXIT_SUCCESS;
}
/* Interpolation Potential */
Potential_interpolation_2d::Potential_interpolation_2d(
const Coordinate_2d& coords, const vector<double>& values)
{
size_t n = coords.size();
for (size_t i = 0; i < n; ++i)
{
Point p(coords.x(i), coords.y(i));
_dt.insert(p);
_value_map.insert(make_pair(p, values[i]));
}
sibson_gradient_fitting_nn_2(
_dt, inserter(_grad_map, _grad_map.begin()),
Data_access_value(_value_map),
GradTraits());
}
