Periodic mesh in a .xml file converted with dolfin-convert

Legacy DOLFIN
,
1

Hi everyone, I have troubles in making a 2D periodic mesh for use with fenics. I have a .geo which is computed into a .msh file using “gmsh -2 file.geo -format msh2”. I then get a .msh file which I convert in the xml format with “dolfin-convert file.msh file.xml”. The command actually returns a .xml file but the mesh seems to be different from the one contained in the .msh file (the .msh file contains 98 elements whereas the .xml only contains 68 elements, though both files have the same number of nodes). When running the python/dolfin script, the .xml is read without raising any error but the results lets me think there is no periodic boundary condiiton.

Here is the .geo file :

SetFactory("OpenCASCADE");
Mesh.CharacteristicLengthMin = 3;
Mesh.CharacteristicLengthMax = 8;
p0 = newp;
Point(p0) = {-16.0, -4.0, 0.0};
p1 = newp;
Point(p1) = {16.0, -4.0, 0};
p2 = newp;
Point(p2) = {16.0, 4.0, 0.0};
p3 = newp;
Point(p3) = {-16.0, 4.0, 0};
l0 = newl;
Line(l0) = {p0, p1};
l1 = newl;
Line(l1) = {p1, p2};
l2 = newl;
Line(l2) = {p2, p3};
l3 = newl;
Line(l3) = {p3, p0};
ll0 = newll;
Line Loop(ll0) = {l0, l1, l2, l3};
s0 = news;
Plane Surface(s0) = {ll0};
Periodic Curve { l1 } = { l3 } Translate { 32.0, 0.0, 0.0 };

Thanks in advance for your help

2

Have you tried msh version 2 (ASCII) ?

Also, please consider reading -