CGAL users discussion list

[Peter Hachenberger <>]

Did you try the Extended_cartesian kernel? It does not compile under
CGAL 3.3.1, but I have a fix. Didn't I send that to you?

Peter

On Wed, 2008-02-06 at 14:09 +0800, Max wrote:
> >Hello Peter
> >
> >From what I get from your mail msg's, AFAIUC, there's
> >the following facts with relate to Nef_3:
> >
> >1. To use half-space nef_3 ctor such as
> >     Nef_polyhedron_3 N(Plane_3(1, 0, 0, -1), Nef_polyhedron_3::INCLUDED);
> >one should use extended kernel;
> >
> >2. Don't use inexact kernels with Nef_3;
> >
> >3. To play with Nef_3 with double type coordinates, one should
> >use SNC_indexed_items as the 2nd template parameter in instantiating
> >a Nef_3 type;
> >
> >4. Extended kernels do not work together with SNC_indexed_items.
> >
> >It seems that there's no choice, of combinition of Nef_3/kernel, for me 
> >to meet these needs:
> >
> >a) I need the half-space Nef_3 ctor; (that means I should used extended 
> >kernel)
> >
> >b) my coordinates is double type; (that means I should use 
> >SNC_indexed_items, but it's
> >incompatible with extended kernel)
> >
> >So this seems to be a deadlock. Is there any solution?
> >
> >Many thanks for your help, Peter.
> >
> 
> I've tested for the following combinitions:
> a) Number type, integer(I) or float(F), more specifcally, 
>       use Gmpz or Gmpzf;
> b) Standard(S) or extended kernel(E), more specifcally, 
>       use Homogeneous<> or Extended_homogeneous<>;
> c) items type for Nef_3: default(D) or SNC_indexed_items(I)
> 
> I've tested for all of the combinitions of [a(I|F), b(S|E), c(D|I)],
> and the results is as follows:
> 
> configuration Result
> -----------------------------------------------------------------------
> [I, S, D]             1.      “Gmpz constructed from non-integer double 
> value” warning
>                               2.      “Constructor not available for this 
> Kernel” warning
> [I, S, I]             “Gmpz constructed from non-integer double value” 
> warning
> [I, E, D]             “Gmpz constructed from non-integer double value” 
> warning
> [I, E, I]             1.      “Gmpz constructed from non-integer double 
> value” warning
>                               2.      Runtime error, at (CGAL) 
> snc_external_structure.h @ line 1090:
>                                       it->second.sort(Halfedge_key_lt());
> [F, S, D]             Runtime error and exit directly:
>                               CGAL error: assertion violation!
>                               Expr: 0
>                               File: 
> e:\lib\CGAL-3.3.1\include\CGAL/Nef_3/Pluecker_line_3.h
>                               Line: 129
>                               Explanation:Pluecker line 0 0 0 0 0 0 
> shouldn't appear!!!
> [F, S, I]             “Constructor not available for this Kernel” warning
> [F, E, D]             Runtime error and exit directly:
>                               CGAL error: assertion violation!
>                               Expr: 0
>                               File: 
> e:\lib\CGAL-3.3.1\include\CGAL/Nef_3/Pluecker_line_3.h
>                               Line: 129
>                               Explanation:Pluecker line 0 0 0 0 0 0 
> shouldn't appear!!!
> [F, E, I]             Runtime error, at (CGAL) snc_external_structure.h @ 
> line 1090:
>                               it->second.sort(Halfedge_key_lt());
> 
> Additionally, I've tested the Exact_predicates_exact_constructions_kernel 
> kernel with the default or index items type for Nef_3, the reaults are
> the same:
> 
> I got a tatic assertion failure in Point_3.h @ line 46:
>   BOOST_STATIC_ASSERT((boost::is_same<Self, typename R_::Point_3>::value));
> 
> Test platform: CGAL 3.3.1(with updates you gave me)+WinXP/SP2+VS2005/SP1
> 
> What I get from the tests is, none of all the combinitions I've tested 
> could 
> give me a clean output.
> 
> >B/Rgds
> >Max
> 
>