CGAL users discussion list

[huanghz <>]

Hi, I am a new user and have some problem when constructing an arrangement
for a Voronoi Diagram.
Firstly, I get a  Delaunay Triangulation for some points:

Delaunay dt;
dt.insert(vertices.begin(), vertices.end());

Then, I use its dual graph to get my Voronoi Diagram:

Delaunay::Edge_iterator eit;
std::vector<X_monotone_curve_2> curves;
for( eit = dt.edges_begin(); eit != dt.edges_end(); eit ++)
{
                CGAL::Object o = dt.dual(eit);
                if (CGAL::object_cast<K::Segment_2>(&o))
                {
                        double p1x = 
(double)CGAL::object_cast<K::Segment_2>(&o)->source().hx();
                        double p1y = 
(double)CGAL::object_cast<K::Segment_2>(&o)->source().hy();
                        Point p1(p1x, p1y); 
                        double p2x = 
(double)CGAL::object_cast<K::Segment_2>(&o)->target().hx();
                        double p2y = 
(double)CGAL::object_cast<K::Segment_2>(&o)->target().hy();
                        Point p2(p2x, p2y);
                        const Segment_2 s(p1,p2);
                        curves.push_back(s);
                }
}

But when I do this, there will be an runtime error:
insert(arr, curves.begin(), curves.end());

CGAL error: precondition violation!
Expression : comp_f(object, parentP->object) != SMALLER
File       : e:\huanghz\lib\cgal-4.2\include\cgal\multiset.h
Line       : 2129
Explanation:
Refer to the bug-reporting instructions at
http://www.cgal.org/bug_report.html

My kernel and traits are defined as follow:
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Arr_linear_traits_2<K> Traits_2;
typedef CGAL::Delaunay_triangulation_2<K> Delaunay;
typedef Traits_2::Point_2 Point;
typedef Traits_2::X_monotone_curve_2 X_monotone_curve_2;
typedef Traits_2::Segment_2 Segment_2;
typedef Traits_2::Ray_2 Ray_2;
typedef Traits_2::Line_2 Line_2;
typedef CGAL::Arrangement_2<Traits_2> Arrangement_2;
typedef Arrangement_2::Vertex_handle Vertex_handle;
typedef Arrangement_2::Halfedge_handle Halfedge_handle;




--
View this message in context: 
http://cgal-discuss.949826.n4.nabble.com/Problems-when-constructing-arrangement-tp4657652.html
Sent from the cgal-discuss mailing list archive at Nabble.com.