mirror of https://github.com/CGAL/cgal
122 lines
4.1 KiB
C++
122 lines
4.1 KiB
C++
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
|
|
#include <CGAL/Kernel/global_functions_2.h>
|
|
|
|
#include <CGAL/Regular_triangulation_2.h>
|
|
#include <CGAL/boost/graph/graph_traits_Regular_triangulation_2.h>
|
|
|
|
#include <CGAL/internal/boost/function_property_map.hpp>
|
|
|
|
#include <boost/graph/kruskal_min_spanning_tree.hpp>
|
|
#include <boost/graph/filtered_graph.hpp>
|
|
|
|
#include <fstream>
|
|
|
|
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
|
|
typedef K::FT FT;
|
|
typedef K::Weighted_point_2 Weighted_point;
|
|
|
|
typedef CGAL::Regular_triangulation_2<K> Triangulation;
|
|
|
|
// As we only consider finite vertices and edges
|
|
// we need the following filter
|
|
|
|
template <typename T>
|
|
struct Is_finite {
|
|
|
|
const T* t_;
|
|
|
|
Is_finite() : t_(NULL) { }
|
|
Is_finite(const T& t) : t_(&t) { }
|
|
|
|
template <typename VertexOrEdge>
|
|
bool operator()(const VertexOrEdge& voe) const {
|
|
return ! t_->is_infinite(voe);
|
|
}
|
|
};
|
|
|
|
template <typename T>
|
|
struct Compute_edge_weight
|
|
{
|
|
const T& t_;
|
|
|
|
Compute_edge_weight(const T& t) : t_(t) { }
|
|
|
|
typedef typename boost::graph_traits<T>::vertex_descriptor vertex_descriptor;
|
|
typedef typename boost::graph_traits<T>::edge_descriptor edge_descriptor;
|
|
|
|
FT operator()(const edge_descriptor ed) const {
|
|
vertex_descriptor svd = source(ed, t_);
|
|
vertex_descriptor tvd = target(ed, t_);
|
|
typename T::Vertex_handle sv = svd;
|
|
typename T::Vertex_handle tv = tvd;
|
|
return CGAL::power_product(sv->point(), tv->point());
|
|
}
|
|
};
|
|
|
|
typedef Is_finite<Triangulation> Filter;
|
|
typedef boost::filtered_graph<Triangulation,Filter,Filter> Finite_triangulation;
|
|
typedef boost::graph_traits<Finite_triangulation>::vertex_descriptor vertex_descriptor;
|
|
typedef boost::graph_traits<Finite_triangulation>::vertex_iterator vertex_iterator;
|
|
typedef boost::graph_traits<Finite_triangulation>::edge_descriptor edge_descriptor;
|
|
|
|
// The BGL makes use of indices associated to the vertices
|
|
// We use a std::map to store the index
|
|
typedef std::map<vertex_descriptor,int> VertexIndexMap;
|
|
VertexIndexMap vertex_id_map;
|
|
|
|
// A std::map is not a property map, because it is not lightweight
|
|
typedef boost::associative_property_map<VertexIndexMap> VertexIdPropertyMap;
|
|
VertexIdPropertyMap vertex_index_pmap(vertex_id_map);
|
|
|
|
int
|
|
main(int argc,char* argv[])
|
|
{
|
|
const char* filename = (argc > 1) ? argv[1] : "data/weighted_points.xyw";
|
|
std::ifstream input(filename);
|
|
Triangulation t;
|
|
Filter is_finite(t);
|
|
Finite_triangulation ft(t, is_finite, is_finite);
|
|
|
|
Weighted_point wp ;
|
|
while(input >> wp){
|
|
t.insert(wp);
|
|
}
|
|
|
|
// Note that with the input "data/weighted_points.xyw", there is one hidden vertex
|
|
std::cout << "number of hidden vertices: " << t.number_of_hidden_vertices() << std::endl;
|
|
|
|
vertex_iterator vit, ve;
|
|
// Associate indices to the vertices
|
|
int index = 0;
|
|
// boost::tie assigns the first and second element of the std::pair
|
|
// returned by boost::vertices to the variables vit and ve
|
|
for(boost::tie(vit,ve)=boost::vertices(ft); vit!=ve; ++vit ){
|
|
vertex_descriptor vd = *vit;
|
|
vertex_id_map[vd]= index++;
|
|
}
|
|
|
|
// We use a custom edge length property map that computes the power distance
|
|
// between the extremities of an edge of the regular triangulation
|
|
typedef Compute_edge_weight<Triangulation> Edge_weight_functor;
|
|
|
|
// In the function call you can see a named parameter: vertex_index_map
|
|
std::list<edge_descriptor> mst;
|
|
boost::kruskal_minimum_spanning_tree(
|
|
ft, std::back_inserter(mst),
|
|
vertex_index_map(vertex_index_pmap).
|
|
weight_map(CGAL::internal::boost_::make_function_property_map<
|
|
edge_descriptor, FT, Edge_weight_functor>(Edge_weight_functor(t))));
|
|
|
|
std::cout << "The edges of the Euclidean mimimum spanning tree:" << std::endl;
|
|
for(std::list<edge_descriptor>::iterator it = mst.begin(); it != mst.end(); ++it){
|
|
edge_descriptor ed = *it;
|
|
vertex_descriptor svd = source(ed,t);
|
|
vertex_descriptor tvd = target(ed,t);
|
|
Triangulation::Vertex_handle sv = svd;
|
|
Triangulation::Vertex_handle tv = tvd;
|
|
std::cout << "[ " << sv->point() << " | " << tv->point() << " ] " << std::endl;
|
|
}
|
|
|
|
return 0;
|
|
}
|