Mixed Finite element ValueError too many values to unpack

dolfinx
1

Hi,

I have a question regarding the Mixed Function spaces. I’ve tried the following code and I got this error.

ValueError: too many values to unpack (expected 2)

import ufl
from dolfinx import fem, io, mesh
from mpi4py import MPI

msh = mesh.create_rectangle(comm=MPI.COMM_WORLD,
                            points=((0.0, 0.0), (2.0, 1.0)), n=(32, 16),
                            cell_type=mesh.CellType.triangle,)

W = ufl.FiniteElement("N1curl", msh.ufl_cell(), 1)
V = ufl.FiniteElement("CG", msh.ufl_cell(), 1)
V = fem.FunctionSpace(msh, ufl.MixedElement([W, V]))

(u1,u2) = ufl.TestFunction(V)

and if I use:

u = ufl.TestFunction(V)
print(u.ufl_shape)

I can see the shape is (3, ) but it cannot split it.

In the previous version of Dolfin, I could easily do this and the program worked fine, but here I am getting this error. I would appreciate it if you could give me some tips to solve this problem.

Ali

2

First of all, you code has several typos, as VV and WW is not defined.
Secondly, you need to use ufl.TestFunctions with an s at the end to use the split command that you are suggesting.

3

Thank you. You are correct about WW and VV. My apologies for that. I edited the text.