Dear all, I tried to build a mixed space with periodic bc on two of the subspaces: meshbase = RectangleMesh(Nx, Ny, Lx, Ly, quadrilateral=True) mesh = ExtrudedMesh(meshbase, Nz, Delta_z) horiz_elt = FiniteElement("DG", quadrilateral, 0) DG1 = FunctionSpace(mesh, horiz_elt) meshbase = PeriodicRectangleMesh(Nx, Ny, Lx, Ly, quadrilateral=True) mesh = ExtrudedMesh(meshbase, Nz, Delta_z) horiz_elt = FiniteElement("DG", quadrilateral, 0) DG2 = FunctionSpace(mesh, horiz_elt) DG3 = FunctionSpace(mesh, horiz_elt) W = DG1 * DG2 * DG3 but got an error message (see below). Is there a way to set periodic bc on two of the three subspaces? Henrik Traceback (most recent call last): File "twophase.py", line 43, in <module> W = DG1 * DG2 * DG3 File "/home/hb111949/Code/firedrake/firedrake/functionspace.py", line 536, in __mul__ return MixedFunctionSpace((self, other)) File "/home/hb111949/.local/lib/python2.7/site-packages/PyOP2-0.11.0_425_g64db689-py2.7-linux-x86_64.egg/pyop2/caching.py", line 161, in __new__ obj = make_obj() File "/home/hb111949/.local/lib/python2.7/site-packages/PyOP2-0.11.0_425_g64db689-py2.7-linux-x86_64.egg/pyop2/caching.py", line 142, in make_obj obj.__init__(*args, **kwargs) File "/home/hb111949/Code/firedrake/firedrake/functionspace.py", line 742, in __init__ self._ufl_element = ufl.MixedElement(*[fs.ufl_element() for fs in self._spaces]) File "/home/hb111949/.local/lib/python2.7/site-packages/ufl/finiteelement/mixedelement.py", line 57, in __init__ domains = tuple(sorted(set(chain(*[element.domains() for element in elements])))) File "/home/hb111949/.local/lib/python2.7/site-packages/ufl/domain.py", line 216, in __lt__ return self.hash_data() < other.hash_data() File "/home/hb111949/.local/lib/python2.7/site-packages/ufl/exproperators.py", line 55, in _lt return LT(left, right) File "/home/hb111949/.local/lib/python2.7/site-packages/ufl/conditional.py", line 144, in __init__ BinaryCondition.__init__(self, "<", left, right) File "/home/hb111949/.local/lib/python2.7/site-packages/ufl/conditional.py", line 72, in __init__ "Expecting scalar arguments.") File "/home/hb111949/.local/lib/python2.7/site-packages/ufl/assertions.py", line 37, in ufl_assert if not condition: error(*message) File "/home/hb111949/.local/lib/python2.7/site-packages/ufl/log.py", line 151, in error raise self._exception_type(self._format_raw(*message)) ufl.log.UFLException: Expecting scalar arguments. -- Dipl.-Math. Henrik Büsing Institute for Applied Geophysics and Geothermal Energy E.ON Energy Research Center RWTH Aachen University ------------------------------------------------------ Mathieustr. 10 | Tel +49 (0)241 80 49907 52074 Aachen, Germany | Fax +49 (0)241 80 49889 ------------------------------------------------------ http://www.eonerc.rwth-aachen.de/GGE hbuesing@eonerc.rwth-aachen.de ------------------------------------------------------