CGAL users discussion list

[Efi Fogel <>]

When you use inexact construction, your program may work on some instances and may fail on other.

We do not guarantee anything.

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On 25 April 2018 at 18:49, Dinesh Shetty <> wrote:

Well my version with 4.4 works

On Wed, Apr 25, 2018 at 3:31 AM Efi Fogel <> wrote:

This could have never worked.

You are using inexact construction.

Change the first line to:

typedef CGAL::Exact_predicates_exact_constructions_kernel Kernel;

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On 24 April 2018 at 22:07, Dinesh Shetty <> wrote:

typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;

typedef Kernel::FT                                        Number_type;

typedef CGAL::Arr_segment_traits_2<Kernel>              Traits;

typedef Traits::Point_2                                 Point;

typedef Traits::X_monotone_curve_2                      Segment;

typedef CGAL::Arrangement_2<Traits>                     Arrangement;

typedef Arrangement::Vertex_handle                      Vertex_handle;

typedef Arrangement::Halfedge_handle                    Halfedge_handle;

typedef Arrangement::Face_handle                        Face_handle;

typedef Arrangement::Vertex_const_handle                Vertex_const_handle;

typedef Arrangement::Halfedge_const_handle              Halfedge_const_handle;

typedef CGAL::Arr_consolidated_curve_data_traits_2<Traits, int>

Data_traits;

typedef Data_traits::Curve_2                               Numbered_segment;

typedef CGAL::Arrangement_2<Data_traits>                   Numbered_arr;

Numbered_arr   arr;

insert(arr, Numbered_segment(Segment(Point(1.6831200000000E+02,-1.3992000000000E+01), Point( 1.2253100000000E+02, -2.0889000000000E+01)), 6));

insert(arr, Numbered_segment(Segment(Point(1.6490200000000E+02, 1.0314000000000E+01), Point( 1.0342400000000E+02, 4.2850000000000E+00)), 11));

insert(arr, Numbered_segment(Segment(Point(1.7217000000000E+02,-3.2611000000000E+01), Point( 9.9756000000000E+01, -4.3728000000000E+01)), 16));

insert(arr, Numbered_segment(Segment(Point(1.4197300000000E+02, 5.4490000000000E+00), Point( 1.4887000000000E+02, -4.0331000000000E+01)), 51));

std::stringstream ss;

Numbered_arr::Vertex_const_iterator   vit;

for (vit = arr.vertices_begin(); vit != arr.vertices_end(); ++vit) 

{

std::map<int, int> Frequency;

Numbered_arr::Halfedge_around_vertex_const_circulator eit, first;

eit = first = vit->incident_halfedges();

do 

{

++Frequency[eit->curve().data().front()];

} while (++eit != first);

ss << "@ ( " << vit->point() << ")" <<std::endl;

for(auto & itr : Frequency)

{

ss<<itr.first<<" apprears "<<itr.second<<"\n";

}

}

Numbered_arr::Edge_const_iterator eit;

std::vector<int> Pid;

for (eit = arr.edges_begin(); eit != arr.edges_end(); ++eit) 

{

Data_traits::Data_container::const_iterator  it;

if(eit->curve().data().size()> 1)

{

Pid.clear();

Pid.reserve(eit->curve().data().size());

for (it = eit->curve().data().begin(); it != eit->curve().data().end(); ++it)

{

Pid.push_back(*it);

}

ss<<"Overlap detected : ";

for(auto & itr : Pid)

ss<<itr<<" ";

ss<<"\n";

}

}

ss << arr.number_of_edges() << " edges:" << std::endl;

for (eit = arr.edges_begin(); eit != arr.edges_end(); ++eit)

ss << "[" << eit->curve() << "]" << std::endl;

On Tue, Apr 24, 2018 at 12:33 PM, Efi Fogel <> wrote:

Please provide a test case that reproduces the problem.

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On 24 April 2018 at 17:32, Dinesh Shetty <> wrote:

When I switched to CGAL 4.12-beta2 from CGAL-4.4, I get following exception thrown

Exception: CGAL ERROR: precondition violation!

Expr: (m_traits.compare_y_at_x_2_object()(p, cv) == EQUAL) && compare_xy(cv.left(), p) == SMALLER && compare_xy(cv.right(), p) == LARGER

File: D:\PE\PE_Software\3rdParty\CGAL\CGAL-4.12-beta2\include\CGAL/Arr_segment_traits_2.h

Line: 714

Any help appreciated..

On stackExchange

https://stackoverflow.com/questions/50004248/cgal-fails-with-insertion-operation-in-2d-arrangements