Cannot create 1d mesh

[dokken]

Frankly, I am getting tired of repeating myself here.

@mekong

#read the lines
mvc = MeshValueCollection("size_t", mesh, mesh.topology().dim())
with XDMFFile("line_mesh.xdmf") as infile:
    infile.read(mvc, "name_to_read")
cf = cpp.mesh.MeshFunctionSizet(mesh, mvc)
xdmf.close()

#read the vertices
mvc = MeshValueCollection("size_t", mesh, mesh.topology().dim()-1)
with XDMFFile("line_mesh.xdmf") as infile:
    infile.read(mvc, "name_to_read")
sf = cpp.mesh.MeshFunctionSizet(mesh, mvc)
xdmf.close()

Please look closely at the definition of sf.
This does not match what is done in:

@dokken

mvc = MeshValueCollection("size_t", mesh, mesh.topology().dim())
with XDMFFile("mesh.xdmf") as infile:
    infile.read(mvc, "name_to_read")
cf = cpp.mesh.MeshFunctionSizet(mesh, mvc)
xdmf.close()

mvc = MeshValueCollection("size_t", mesh, mesh.topology().dim()-1)
with XDMFFile("surface.xdmf") as infile:
    infile.read(mvc, "name_to_read")
sf = cpp.mesh.MeshFunctionSizet(mesh, mvc)
xdmf.close()

where you observe that the surface/facet data is read from a different file that the mesh itself, which I have now stated multiple times before.

@dokken

You haven’t stored your facet markers to file. See for instance: How to read a physical object from a xdmf file - #7 by dokken where I already showed you this.

@dokken

# create mesh with new method
mesh = Mesh()
with XDMFFile(input_directory + "/triangle_mesh.xdmf") as infile:
    infile.read(mesh)
mvc = MeshValueCollection("size_t", mesh, 1)
with XDMFFile(input_directory + "/line_mesh.xdmf") as infile:
    infile.read(mvc, "name_to_read")