CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Which way are you going? From arrangement to Mesh_2 or the way around?

You can use CGAL::Cartesian_converter to convert the point from the
arrangement that is using EPECK to EPICK for Mesh_2.

Basically,

CGAL::Cartesion_converter<CGAL::EPECK, CGAL::EPICK> to_epick;

EPECK::Point_3 ept;
EPICK::Point_3 pt = to_epick(ept);

HTH,

Sebastien.


On 05/03/2018 05:37 PM, Dinesh Shetty wrote:
> I am really having hard time switching from 4.4 to 4.12. Seems like 
> arrangement crash if I don’t use exact construction but constrained 
> Delaunay mesh does not compile with exact construction
>
> On Thu, Apr 26, 2018 at 12:32 AM Efi Fogel < 
> <mailto:>> wrote:
>
>     The assertion that causes the error has been there for ever. It is
>     active only in debug mode. It's possible that it has never worked in
>     debug mode and still works in release mode. In any case I suggest
>     that you switch to using an exact construction kernel, cause even if
>     it has been working so far, the failure is around the corner
>     regardless of the assertion.
>
>     On Wed, Apr 25, 2018, 19:09 Dinesh Shetty 
> <
>     
> <mailto:>>
>  wrote:
>
>         It worked for many years for all the problems I have tried, but
>         I switch to 4.12 now it breaks
>
>         On Wed, Apr 25, 2018 at 10:55 AM Efi Fogel 
> <
>         
> <mailto:>>
>  wrote:
>
>             When you use inexact construction, your program may work on
>             some instances and may fail on other.
>             We do not guarantee anything.
>
>
>                 ____  _        ____             _
>                /_____/_) o    /__________  __  //
>               (____ (   (    (    (_/ (_/-(-'_(/
>                                       _/
>
>
>
>             On 25 April 2018 at 18:49, Dinesh Shetty
>             
> <
>  
> <mailto:>>
>  wrote:
>
>                 Well my version with 4.4 works
>
>                 On Wed, Apr 25, 2018 at 3:31 AM Efi Fogel
>                 
> <
>  
> <mailto:>>
>  wrote:
>
>                     This could have never worked.
>                     You are using inexact construction.
>                     Change the first line to:
>
>                     typedef
>                     CGAL::Exact_predicates__exact__constructions_kernel
>                     Kernel;
>
>                         ____  _        ____             _
>                        /_____/_) o    /__________  __  //
>                       (____ (   (    (    (_/ (_/-(-'_(/
>                                               _/
>
>
>
>                     On 24 April 2018 at 22:07, Dinesh Shetty
>                     
> <
>                     
> <mailto:>>
>  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
>                         
> <
>  
> <mailto:>>
>                         wrote:
>
>                             Please provide a test case that reproduces
>                             the problem.
>
>                                 ____  _        ____             _
>                                /_____/_) o    /__________  __  //
>                               (____ (   (    (    (_/ (_/-(-'_(/
>                                                       _/
>
>
>
>                             On 24 April 2018 at 17:32, Dinesh Shetty
>                             
> <
>                             
> <mailto:>>
>  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