Hi all,

I'm implementing 3D momentum equation for horizontal velocity components (u,v) that live in RT1xP1 space. So the space is 3D but the field only has 2 components. I'm getting some errors from FFC related to missing quadrature rules:

File "/home/tuomas/.local/lib/python2.7/site-packages/FFC-1.6.0.dev0-py2.7-linux-x86_64.egg/ffc/quadrature/quadraturetransformerbase.py", line 1031, in _create_mapping_basis
    name, non_zeros, zeros, ones = self.name_map[name]
KeyError: 'FE1_C2'

If I interpret that correctly, FE1_C2 is a quad rule for the third component of the vector space, which doesn't exist in this case. If I replace the RT space with DG (dim=2) everything works. Is this a FFC issue or am I doing this wrong?

- Tuomas

---

from firedrake import *

mesh2d = UnitSquareMesh(10, 10)
layers = 6
mesh = ExtrudedMesh(mesh2d, layers, -1.0/layers)

#U = VectorFunctionSpace(mesh, 'DG', 1, vfamily='CG', vdegree=1, dim=2)
U = FunctionSpace(mesh, 'RT', 1, vfamily='CG', vdegree=1)
P1 = FunctionSpace(mesh, 'CG', 1, vfamily='CG', vdegree=1)

f = Function(P1)
f.interpolate(Expression('-x[0]'))
sol = Function(U)

test = TestFunction(U)

# sol + grad(f) = 0
F = inner(sol, test)*dx + (grad(f)[0]*test[0] + grad(f)[1]*test[1])*dx

solve(F == 0, sol)
print sol.dat.data.min(), sol.dat.data.max()