How to extract and use physical labels from GMSH surfaces on FEniCS (2D mesh)

mesh
5

@AMM
Secondly, writing your mesh to xdmf as described in the next snippets works for me:

import meshio
msh = meshio.read("amm.msh")

meshio.write("mesh.xdmf", meshio.Mesh(points=msh.points, cells={"triangle": msh.cells["triangle"]}))
meshio.write("mf.xdmf", meshio.Mesh(points=msh.points, cells={"triangle": msh.cells["triangle"]},
                                    cell_data={"triangle": {"name_to_read": msh.cell_data["triangle"]["gmsh:physical"]}}))

from dolfin import *
mesh = Mesh()
with XDMFFile("mesh.xdmf") as infile:
    infile.read(mesh)
mvc = MeshValueCollection("size_t", mesh, 2)
with XDMFFile("mf.xdmf") as infile:
    infile.read(mvc, "name_to_read")
mf = cpp.mesh.MeshFunctionSizet(mesh, mvc)

domains = MeshFunction("size_t", mesh, mesh.topology().dim())
dx = Measure("dx",domain=mesh, subdomain_data=mf)
print(assemble(Constant(1)*dx))
print(assemble(Constant(1)*dx(1)))
print(assemble(Constant(1)*dx(2)))
print(assemble(Constant(1)*dx(3)))
print(assemble(Constant(1)*dx(4)))

as it gives the output:

1.0
0.25
0.25
0.25
0.25
1 Like