Strange Error building mixed FunctionSpace on the "same???" FEniCS version!

Question

Hi, I can build a mixed Nedelec-Space in my FEniCS Version 2016.2.0 installed in 12/2016 as follows with no errors:

import dolfin as df

p = 1
mesh = df.UnitCubeMesh(10, 10, 10)
ele = df.FiniteElement("N1curl", mesh.ufl_cell(), p)
print(ele)
W = df.FunctionSpace(mesh, df.MixedElement([ele, ele]))

The output is:

 <N1curl1 on a tetrahedron>

Now a colleague tries exactly the same code snippet with FEniCS 2016.2.0 installed within the last days (also on Ubuntu) and he gets the following output/error on 2 different PC's:

 <N1curl1 on a <Domain built from <tetrahedron cell in 3D> with label None>>
 Traceback (most recent call last):
    File "debug.py", line 19, in <module>
      W = df.FunctionSpace(mesh, df.MixedElement([ele, ele]))
 TypeError: __init__() takes at least 4 arguments (3 given)

Why is this happening? Is there a difference in the two FEniCS 2016.2.0 versions? At least the print function gives something diffent ...

Comments

Works fine for me both with version 2016.2.0 and the latest development version. I have tested with the Ubuntu packages and using the docker images. No problem with any of them.

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Thank you! Annother colleague has no issues as well. So the problem must be somethere else.

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Maybe he is mixing multiple versions of FEniCS. For example he can have 2016.2.0 installed in /usr from the Ubuntu packages but have a different version installed in some other location like /usr/local or ~/.local. In that case, it would help to remove the other version. If not, then please show us the complete error message.

Answer 1

Everything is fine, my colleague was accidently using a 2016.1 FEniCS version. In this version, you had to define mixed spaces via MixedFunctionSpace, which was deprecated in 2016.2.