Hello, I am running the following script and want to run the same equation in 3D mesh. Could you give an idea how can I change the 2D mesh script to 3D mesh script?
https://fenicsproject.org/olddocs/dolfin/dev/python/demos/cahn-hilliard/demo_cahn-hilliard.py.html
For the mesh, I think you can just use UnitCubeMesh https://fenicsproject.org/olddocs/dolfin/2016.1.0/python/programmers-reference/cpp/mesh/UnitCubeMesh.html
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@Kei_Yamamoto Thanks a lot for your message. I used UnitCubeMesh and got this error. Do you know what this message means? I cannot get what the “shapes” means.
Can't add expressions with different shapes.
Traceback (most recent call last):
File "demo_cahn-hilliard.py", line 258, in <module>
f = 100*c**2*(1-c)**2
File "/usr/lib/python3/dist-packages/ufl/exproperators.py", line 232, in _rsub
return Sum(o, -self)
File "/usr/lib/python3/dist-packages/ufl/algebra.py", line 41, in __new__
error("Can't add expressions with different shapes.")
File "/usr/lib/python3/dist-packages/ufl/log.py", line 158, in error
raise self._exception_type(self._format_raw(*message))
ufl.log.UFLException: Can't add expressions with different shapes.
@tkoyama010
I can’t tell what is causing error without looking your code but, my understanding of shgapes
is the same as dimensions
. So, you are probably trying add something that doesn’t have the same dimension (For example, trying to add scalar and vector).
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