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[Garth Wells <>]

I've been running into some issues with mesh generation in 3D. I'm creating
meshes of rather simple polyhedra (tetrahedra, cubes), but have been finding
that the generation randomly fails at times. I'm also seeing a dependency on
the gcc version and optimisation level. The code at the end of this message,
taken from

   
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Mesh_3/Chapter_main.html#Subsection_50.3.5

runs without error with g++ 4.6.1, but with g++ 4.4.6 and the -O2 or -O3
flag I get the error 

    terminate called after throwing an instance of
'CGAL::Precondition_exception'
      what():  CGAL ERROR: precondition violation!
    Expr: index != Subdomain_index()
    File: /usr/include/CGAL/Mesh_3/Mesh_complex_3_in_triangulation_3_base.h
    Line: 160
    Aborted

I've tested with CGAL 3.8 and 3.9. The code is compiled using

    g++ -O2 -frounding-math  test.cpp -lCGAL -lboost_thread -lmpfr -lgmp

Any help with this would be greatly appreciated.

Garth




#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Mesh_triangulation_3.h>
#include <CGAL/Mesh_complex_3_in_triangulation_3.h>
#include <CGAL/Mesh_criteria_3.h>
#include <CGAL/Polyhedral_mesh_domain_with_features_3.h>
#include <CGAL/make_mesh_3.h>

// Domain
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Polyhedral_mesh_domain_with_features_3<K> Mesh_domain;

// Triangulation
typedef CGAL::Mesh_triangulation_3<Mesh_domain>::type Tr;
typedef CGAL::Mesh_complex_3_in_triangulation_3<
  Tr,Mesh_domain::Corner_index,Mesh_domain::Curve_segment_index> C3t3;

// Criteria
typedef CGAL::Mesh_criteria_3<Tr> Mesh_criteria;

// To avoid verbose function and named parameters call
using namespace CGAL::parameters;

int main()
{
  // Create domain
  Mesh_domain domain("fandisk.off");

  // Get sharp features
  domain.detect_features();

  // Mesh criteria
  Mesh_criteria criteria(edge_size = 0.025,
                         facet_angle = 25, facet_size = 0.05, facet_distance
= 0.005,
                         cell_radius_edge_ratio = 3, cell_size = 0.05);

  // Mesh generation
  C3t3 c3t3 = CGAL::make_mesh_3<C3t3>(domain, criteria);
}

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