>>> from firedrake import *

>>> m = IcosahedralSphereMesh(radius=3, refinement_level=3)

>>> mesh = ExtrudedMesh(m, 5, layer_height=0.1, extrusion_type='radial')

>>> horiz_elt = FiniteElement("CG", triangle, 1)

>>> vert_elt = FiniteElement("CG", interval, 1)

>>> elt = OuterProductElement(horiz_elt, vert_elt)

>>> V = FunctionSpace(mesh, elt)

>>> u = TrialFunction(V)

>>> v = TestFunction(V)

>>> f = Function(V)

>>> f.interpolate(Expression("(2*x[0])+(sin(3*x[1]))+(cos(0.5*x[2]))"))

Coefficient(FunctionSpace(Mesh(OuterProductVectorElement(OuterProductElement(FiniteElement('Lagrange', triangle, 1), FiniteElement('Lagrange', interval, 1), OuterProductCell(triangle, interval)), dim=3), 4), OuterProductElement(FiniteElement('Lagrange', triangle, 1), FiniteElement('Lagrange', interval, 1), OuterProductCell(triangle, interval))), 3)

>>> a = (dot(grad(v), grad(u)) + v * u) * dx

>>> L = f * v * dx

>>> solve(a == L, u, solver_parameters={'ksp_type': 'cg'})

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "/Users/master/firedrake/lib/python2.7/site-packages/firedrake/solving.py", line 120, in solve

    _solve_varproblem(*args, **kwargs)

  File "/Users/master/firedrake/lib/python2.7/site-packages/firedrake/solving.py", line 132, in _solve_varproblem

    nest = _extract_args(*args, **kwargs)

  File "/Users/master/firedrake/lib/python2.7/site-packages/firedrake/solving.py", line 259, in _extract_args

    u = _extract_u(args[1])

  File "/Users/master/firedrake/lib/python2.7/site-packages/firedrake/solving.py", line 299, in _extract_u

    raise RuntimeError("Expecting second argument to be a Coefficient")

RuntimeError: Expecting second argument to be a Coefficient