Dolfinx different material in newest version

dolfinx
1

Hi everyone, I tried to realize the two different material on the domain with two methods:
one is

def conductor(x):
    return x[0] < 0.1 + np.finfo(float).eps

conductor_domain = locate_entities_geometrical(mesh, mesh.topology.dim-1,
                                               conductor, boundary_only=False)
dx = Measure('dx', subdomain_data=conductor_tag)
print(dolfinx.fem.assemble_scalar(dolfinx.Constant(mesh, 1)*dx(1)))

It outputs about 0.11 and should be 0.1

The other method:

V = dolfinx.FunctionSpace(mesh, ('DG', 0))
w = dolfinx.Function(V)

x = V.tabulate_dof_coordinates()
for i in range(x.shape[0]):
    if x[i][0] <= 0.1:
        w.vector.setValueLocal(i, 6)
    else:
        w.vector.setValueLocal(i, 2)

with XDMFFile(dolfinx.MPI.comm_world, "w.xdmf",
          encoding=XDMFFile.Encoding.HDF5) as file:
file.write(w)

But I cannot save w and it reports “segment error”

2

Duplicate of Dolfinx Discontinuous Expressions SIGSEGV, Which is Fixed in https://github.com/FEniCS/dolfinx/pull/931