Error from solving using mini element

Question

Hi,

I received the following error when solving a problem using a mixed function containing mini element as defined by:

V = FunctionSpace(mesh, "CG", 1)
B = FunctionSpace(mesh, "Bubble", 4)
VB = (V+B)*(V+B)*(V+B)
Q = FunctionSpace(mesh, "DG",0)
Q2 = FunctionSpace(mesh, "CG",2)
Pspace = FunctionSpace(mesh, "Real", 0)
W = MixedFunctionSpace([VB,Q,Q2,Q2,Pspace])

A, b = assemble_system(Jac, -F, bcs_du, form_compiler_parameters={'quadrature_degree': quad_degree})
File "/usr/lib/python2.7/dist-packages/dolfin/fem/assembling.py", line 339, in assemble_system
assembler.assemble(A_tensor, b_tensor)
RuntimeError: tabulate_dof_coordinates is not defined for this element

Anybody encounter this problem before?

Answer 1

Hi, the way dual basis for enriched elements was computed resulted in a basis which was not nodal, see here. The issue is not yet resolved and in the mean time some functionality, tabulate_* and etc, was disabled.

Comments

Thanks MiroK! Is there any workaround currently to use enriched element to solve nonlinear variational problem?