CSGCGALMeshGenerator2D generates bad mesh

[Felix Ospald]

C++ Example to reproduce:

#include <dolfin.h>

int main()
{
        dolfin::Mesh mesh;
        dolfin::Circle primitive(0, 0, 1, 4);
        dolfin::CSGCGALMeshGenerator2D meshgen(primitive);
        meshgen.generate(mesh);
        std::cout << mesh.hmin() << " " << mesh.hmax() << " " << mesh.rmin() << " " << mesh.rmax() << std::endl;
        return 0;
}

prints: 0.0184443 inf 0 0.00873079

for 1.4.0 and 1.2.0: 0.0184443 0.0349987 0.00356169 0.00873079

Consequently assembling a matrix contains inf, nan, values... This happens also for other mesh resolutions.

Is there a simple fix for this?help I could not find out where the problem is. I also compiled 1.3 with the same CGAL version as 1.4, but it did not fix the problem. I'd like to use 1.3. since 1.4 requires a lot of changes to my code.

[Tianyi Li]

Try setting in your bashrc/bash_profile file

export LC_ALL=en_US.UTF-8  
export LANG=en_US.UTF-8

It solved the problem in my case, so give a try...

[Felix Ospald]

This did not work.

[Benjamin Dam Kehlet]

This is probably a duplicate of #224 ( https://bitbucket.org/fenics-project/dolfin/issue/224/cgal-produces-degenerate-cells ) which has been fixed in 1.4.

I don't know of any fix except patching dolfin/generation/CSGCGALMeshgenerator2D.cpp. If you are building Dolfin from source, you could try to backport the fix by replacing that file with the version from 1.4.

[Prof Garth Wells]

CGAL-based mesh generation is being moved into mshr.