ffc issue building dolfin-2017.2.0

[Adrian Jackson]

Hi,

I'm trying to build dolfin 2017.2.0 in a container but am getting this
error:

Traceback (most recent call last):
File "/usr/bin/ffc", line 9, in <module>
load_entry_point('fenics-ffc==2017.2.0', 'console_scripts', 'ffc')()
File
"/usr/lib/python2.7/site-packages/fenics_ffc-2017.2.0-py2.7.egg/ffc/main.py",
line 217, in main
resultcode = _compile_files(args, parameters, enable_profile)
File
"/usr/lib/python2.7/site-packages/fenics_ffc-2017.2.0-py2.7.egg/ffc/main.py",
line 256, in _compile_files
code_h, code_c = compile_ufl_data(ufd, prefix, parameters)
File
"/usr/lib/python2.7/site-packages/fenics_ffc-2017.2.0-py2.7.egg/ffc/main.py",
line 102, in compile_ufl_data
parameters=parameters)
File
"/usr/lib/python2.7/site-packages/fenics_ffc-2017.2.0-py2.7.egg/ffc/compiler.py",
line 150, in compile_element
prefix, parameters, jit)
File
"/usr/lib/python2.7/site-packages/fenics_ffc-2017.2.0-py2.7.egg/ffc/compiler.py",
line 190, in compile_ufl_objects
ir = compute_ir(analysis, prefix, parameters, jit)
File
"/usr/lib/python2.7/site-packages/fenics_ffc-2017.2.0-py2.7.egg/ffc/representation.py",
line 171, in compute_ir
for e in elements]
File
"/usr/lib/python2.7/site-packages/fenics_ffc-2017.2.0-py2.7.egg/ffc/representation.py",
line 203, in _compute_element_ir
fiat_element = create_element(ufl_element)
File
"/usr/lib/python2.7/site-packages/fenics_ffc-2017.2.0-py2.7.egg/ffc/fiatinterface.py",
line 99, in create_element
element = _create_fiat_element(ufl_element)
File
"/usr/lib/python2.7/site-packages/fenics_ffc-2017.2.0-py2.7.egg/ffc/fiatinterface.py",
line 196, in _create_fiat_element
element = ElementClass(fiat_cell, degree)
File "build/bdist.linux-x86_64/egg/FIAT/lagrange.py", line 56, in __init__
File "build/bdist.linux-x86_64/egg/FIAT/polynomial_set.py", line 176,
in __init__
File "build/bdist.linux-x86_64/egg/FIAT/expansions.py", line 375, in
tabulate_derivatives
File "build/bdist.linux-x86_64/egg/FIAT/expansions.py", line 104, in
_tabulate_dpts
File "build/bdist.linux-x86_64/egg/FIAT/expansions.py", line 50, in
form_derivative
File "/usr/lib/python2.7/site-packages/sympy/core/function.py", line
1993, in diff
return Derivative(f, *symbols, **kwargs)
File "/usr/lib/python2.7/site-packages/sympy/core/function.py", line
1117, in __new__
it cannot be differentiated.''' % expr))
ValueError:
Since there are no variables in the expression [0, 0, 0], it cannot be
differentiated.

It's failing in the form building, at form
demo/undocumented/elasticity/cpp/Elasticity.ufl. Playing with:

ffc -l dolfin demo/undocumented/elasticity/cpp/Elasticity.ufl I can see
it fails on the element line below.

cell = tetrahedron
element = VectorElement("Lagrange", cell, 1)

Any ideas what's gone wrong? I'm guessing something is screwed up with
my ffc install...

cheers

adrianj

--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

[Jan Blechta]

This is a regression in SymPy 1.2 relased few days ago. It is patched
in FIAT master. You can backport this patch to the lates FIAT release:
https://bitbucket.org/fenics-project/fiat/commits/8ceb29a3b9b14668b9d387321a3f8f4126f9a159
or install older sympy

pip3 install --upgrade sympy==1.1.1

We will think about how to prevent this happening in containers.

Jan

[Björn Baran]

I had the same issue as Adrian with dolfin 2018.1.0 in Anaconda 5.2.

After I saw Jans post, I used the following line to create the Anaconda environment:

conda create -n fenicsproject -c conda-forge fenics scipy sympy=1.1.1  matplotlib ipython spyder

This solved the issue for me. Thank you Jan for the solution.

Björn

[Jan Heiland]

Same thing when building from source.

Downgrade of sympy solved this issue.

Looks like the patch in FIAT master has not reached the pip repositories yet.