ImportError: cannot import name 'AbstractFiniteElement' from 'ufl.finiteelement'

installation
1

After installing in WSL2, Ubuntu 22.04.3 I’m finding that when running demo_elasticity.py as cloned from github’s url for dolfinx package::::

prusso@Yoga730-15ikb:~/dolfinx/python$  cd /home/prusso/dolfinx/python ; /usr/bin/env /bin/python3 /home/prusso/.vscode-server/extensions/ms-python.python-2023.22.1/pythonFiles/lib/python/debugpy/adapter/../../debugpy/launcher 39953 -- /home/prusso/dolfinx/python/demo/demo_elasticity.py 
Traceback (most recent call last):
  File "/home/prusso/dolfinx/python/demo/demo_elasticity.py", line 31, in <module>
    import dolfinx
  File "/usr/lib/petsc/lib/python3/dist-packages/dolfinx/__init__.py", line 40, in <module>
    from dolfinx import fem, geometry, graph, io, jit, la, log, mesh, nls, plot
  File "/usr/lib/petsc/lib/python3/dist-packages/dolfinx/fem/__init__.py", line 12, in <module>
    from dolfinx.fem.assemble import (apply_lifting, assemble_matrix,
  File "/usr/lib/petsc/lib/python3/dist-packages/dolfinx/fem/assemble.py", line 22, in <module>
    from dolfinx.fem.forms import Form
  File "/usr/lib/petsc/lib/python3/dist-packages/dolfinx/fem/forms.py", line 17, in <module>
    from dolfinx import default_scalar_type, jit
  File "/usr/lib/petsc/lib/python3/dist-packages/dolfinx/jit.py", line 17, in <module>
    import ffcx.codegeneration.jit
  File "/usr/lib/python3/dist-packages/ffcx/codegeneration/jit.py", line 21, in <module>
    import ffcx.naming
  File "/usr/lib/python3/dist-packages/ffcx/naming.py", line 16, in <module>
    from .element_interface import convert_element
  File "/usr/lib/python3/dist-packages/ffcx/element_interface.py", line 12, in <module>
    import basix.ufl
  File "/home/prusso/.local/lib/python3.10/site-packages/basix/ufl.py", line 15, in <module>
    from ufl.finiteelement import AbstractFiniteElement as _AbstractFiniteElement
ImportError: cannot import name 'AbstractFiniteElement' from 'ufl.finiteelement' (/usr/lib/python3/dist-packages/ufl/finiteelement/__init__.py)
prusso@Yoga730-15ikb:~/dolfinx/python$

Anyone know why this particular ImportError and/or how to make things resolve and start to run the script?

2

You can’t mix an installation of dolfinx from the PPA with an installation of basix from pip. Run pip uninstall fenics-basix and verify that you are prompted to remove /home/prusso/.local/lib/python3.10/site-packages/basix.

Furthermore don’t go and download the demos from GitHub, because they might be for a newer version than the one you have installed. When install from the PPA, you have a package

dolfinx-doc Documentation and demo programs for DOLFIN

that install demos in /usr/share/doc/dolfinx. Copy them from there to your home.

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