Hi, How do I fix the following error for the solver? File "2d_compressible_stratified.py", line 195, in <module> solver = LinearVariationalSolver(problem, solver_parameters={'ksp_rtol': 1e-14}) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/firedrake/firedrake/variational_solver.py", line 286, in __init__ super(LinearVariationalSolver, self).__init__(*args, **kwargs) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/firedrake/firedrake/variational_solver.py", line 156, in __init__ pre_function_callback=pre_f_callback) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/firedrake/firedrake/solving_utils.py", line 226, in __init__ appctx=appctx) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/firedrake/firedrake/assemble.py", line 120, in allocate_matrix allocate_only=True) File "<decorator-gen-279>", line 2, in _assemble File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/firedrake/firedrake/utils.py", line 62, in wrapper return f(*args, **kwargs) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/firedrake/firedrake/assemble.py", line 192, in _assemble kernels = tsfc_interface.compile_form(f, "form", parameters=form_compiler_parameters, inverse=inverse) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/firedrake/firedrake/tsfc_interface.py", line 193, in compile_form number_map).kernels File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/PyOP2/pyop2/caching.py", line 200, in __new__ obj = make_obj() File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/PyOP2/pyop2/caching.py", line 190, in make_obj obj.__init__(*args, **kwargs) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/firedrake/firedrake/tsfc_interface.py", line 112, in __init__ tree = tsfc_compile_form(form, prefix=name, parameters=parameters) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/tsfc/tsfc/driver.py", line 44, in compile_form fd = ufl_utils.compute_form_data(form) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/tsfc/tsfc/ufl_utils.py", line 56, in compute_form_data do_estimate_degrees=do_estimate_degrees, File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/ufl/ufl/algorithms/compute_form_data.py", line 387, in compute_form_data check_form_arity(preprocessed_form, self.original_form.arguments()) # Currently testing how fast this is File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/ufl/ufl/algorithms/check_arities.py", line 152, in check_form_arity check_integrand_arity(itg.integrand(), arguments) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/ufl/ufl/algorithms/check_arities.py", line 145, in check_integrand_arity args = map_expr_dag(rules, expr, compress=False) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/ufl/ufl/corealg/map_dag.py", line 37, in map_expr_dag result, = map_expr_dags(function, [expression], compress=compress) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/ufl/ufl/corealg/map_dag.py", line 86, in map_expr_dags r = handlers[v._ufl_typecode_](v, *[vcache[u] for u in v.ufl_operands]) File "/usr/not-backed-up/firedrake/2017-02-28/firedrake/src/ufl/ufl/algorithms/check_arities.py", line 42, in sum raise ArityMismatch("Adding expressions with non-matching form arguments {0} vs {1}.".format(a, b)) ufl.algorithms.check_arities.ArityMismatch: Adding expressions with non-matching form arguments (Argument(WithGeometry(FunctionSpace(<firedrake.mesh.MeshTopology object at 0x7f105c981410>, VectorElement(FiniteElement('Discontinuous Lagrange', triangle, 2), dim=2), name=None), Mesh(VectorElement(FiniteElement('Lagrange', triangle, 1), dim=2), 1)), 0, None), Argument(WithGeometry(FunctionSpace(<firedrake.mesh.MeshTopology object at 0x7f105c981410>, VectorElement(FiniteElement('Discontinuous Lagrange', triangle, 2), dim=2), name=None), Mesh(VectorElement(FiniteElement('Lagrange', triangle, 1), dim=2), 1)), 1, None)) vs (Argument(WithGeometry(FunctionSpace(<firedrake.mesh.MeshTopology object at 0x7f105c981410>, VectorElement(FiniteElement('Discontinuous Lagrange', triangle, 2), dim=2), name=None), Mesh(VectorElement(FiniteElement('Lagrange', triangle, 1), dim=2), 1)), 0, None),).