Having
mesh = UnitSquareMesh(2, 2)
Q = FunctionSpace(mesh, 'DG', 0)
this works as expected
R = mesh.ufl_cell().circumradius
R = project(R, Q)
but this fails
h = mesh.ufl_cell().max_facet_edge_length
h = project(h, Q)
when compiling generated code with error: 'facet_area' was not declared...
Does max_facet_edge_length return lengths of the longest edge of a cell as I expected or does it do something else? If so, is there some implementation of this? Or should I loop over cells and their edges to compute h manually?