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C1 continuous functionspace (hermite) for interval and quad mesh in dolfinx #869
Description
dolfinx.fem.functionspace(mesh_r, basix.ufl.element(
"HER", 'interval', 2, shape=(3, )))
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
File /usr/lib/python3/dist-packages/basix/finite_element.py:903, in string_to_family(family, cell)
902 try:
--> 903 return families[family]
904 except KeyError:
KeyError: 'HER'
During handling of the above exception, another exception occurred:
ValueError Traceback (most recent call last)
Cell In[6], line 1
----> 1 dolfinx.fem.functionspace(mesh_r, basix.ufl.element(
2 "HER", 'interval', 2, shape=(3, )))
File /usr/lib/python3/dist-packages/basix/ufl.py:1988, in element(family, cell, degree, lagrange_variant, dpc_variant, discontinuous, shape, symmetry, dtype)
1985 if family == "DPC":
1986 discontinuous = True
-> 1988 family = _basix.finite_element.string_to_family(family, cell.name)
1990 # Default variant choices
1991 EF = _basix.ElementFamily
File /usr/lib/python3/dist-packages/basix/finite_element.py:905, in string_to_family(family, cell)
903 return families[family]
904 except KeyError:
--> 905 raise ValueError(f"Unknown element family: {family} with cell type {cell}")
ValueError: Unknown element family: HER with cell type interval
Similarly for quad mesh,
dolfinx.fem.functionspace(mesh, basix.ufl.element(
"HER", 'quadrilateral', 2, shape=(3, )))
ValueError: Unknown element family: HER with cell type quadrilateral
I don't find any option to implement C1 continuity requirement for dolfinx. Can you provide a way to solve this issue which is available and tested?
Activity
mscroggs commentedon Oct 25, 2024
A Hermite Basix element can be created using
basix.create_elementbut C1 continuous elements are not yet supported in FFCx so these will not work with DOLFINxbagla0 commentedon Oct 25, 2024
Thanks @mscroggs for the quick response.
Is there any example or method available in dolfinx, where they solved this C1 requirement through an alternative way? My weak form contains second order derivative.