Hi team, I'm running into "NotImplemented" exception when trying to set component of a vector field using DirichletBC(), on extruded mesh. Basically I'm trying to set the vertical component of the field to zero throughout the domain. Is there anyway around this? Many thanks, -TJ P.S. I think my function space below is perhaps not ideal, it has more DoFs than necessary. But I'm having difficulty in getting something like below to work # V_h = FiniteElement("CG", "quadrilateral", 1) # V_v = FiniteElement("DG", "interval", 0) # V_elt = HDivElement(TensorProductElement(V_h, V_v)) # V = FunctionSpace(mesh, V_elt) Code skeleton --------------------------------------------------------------------------- m = RectangleMesh(10,10,10,10,quadrilateral=True) mesh = ExtrudedMesh(m, layers=1) V = VectorFunctionSpace(mesh, "CG", 1) bc0 = DirichletBC(V.sub(2), Constant(0.0), "top") bc1 = DirichletBC(V.sub(2), Constant(0.0), "bottom") Error message --------------------------------------------------------------------------- NotImplementedError Traceback (most recent call last) <ipython-input-176-0fe88457c2f0> in <module>() ----> 1 bc0 = DirichletBC(V.sub(2), Constant(0.0), "top") 2 bc1 = DirichletBC(V.sub(2), Constant(0.0), "bottom") /home/ts2914/projects/firedrake/local/lib/python2.7/site-packages/firedrake/bcs.pyc in __init__(self, V, g, sub_domain, method) 60 61 if V.extruded and V.component is not None: ---> 62 raise NotImplementedError("Indexed VFS bcs not implemented on extruded meshes") 63 64 @property NotImplementedError: Indexed VFS bcs not implemented on extruded meshes