I solve the stokes equations on a square domain. Minimal code:
mesh = UnitSquareMesh(8, 8)
P2 = VectorElement("Lagrange", mesh.ufl_cell(), 2)
P1 = FiniteElement("Lagrange", mesh.ufl_cell(), 1)
TH = P2 * P1
W = FunctionSpace(mesh, TH)
def bottom(x, on_boundary): return near(x[1],0.0)
def left(x, on_boundary): return near(x[0],0.0)
bc_b = DirichletBC(W.sub(0), Constant((1.0,0.0)), bottom);
bc_l = DirichletBC(W.sub(0), Constant((0.0,0.0)), left);
bc = [bc_b, bc_l]
(u, p) = TrialFunctions(W)
(v, q) = TestFunctions(W)
a = inner(grad(u), grad(v))*dx + div(v)*p*dx + q*div(u)*dx
L = inner( Constant((0.0,0.0)), v)*dx
U = Function(W)
M = p * dx
solve(a == L, U, bc, tol=0.1, M=M)
This code runs if I change the last line to:
solve(a == L, U, bc)
As written in fails with the message:
Unable to extract all indices.
...
*** Error: Unable to perform just-in-time compilation of form.
I also get the same error if I replace the last line with the code from the Auto adaptive Poisson equation demo,
problem = LinearVariationalProblem(a, L, U, bc)
solver = AdaptiveLinearVariationalSolver(problem, M)
solver.parameters["error_control"]["dual_variational_solver"]["linear_solver"] = "cg"
solver.parameters["error_control"]["dual_variational_solver"]["symmetric"] = True
solver.solve(0.1)
