Dofmap construction fails for VectorFunctionSpace(mesh, 'CG', 3, restriction='facet')

[Prof Garth Wells]

The below code reproduces the error:

from dolfin import *
mesh = UnitSquareMesh(2, 2)
V = VectorFunctionSpace(mesh, 'CG', 3, restriction='facet')

[Chris Richardson]

Seems to be around line 1174 of DofMapBuilder.cpp - I'm not sure what to fix, but I've put an assert in, which fails... see branch chris/fix-issue-444

[Chris Richardson]

I'm not sure, but the bug could possibly be in ffc. I think the scalar subdofmap of a restricted VectorFunctionSpace should also be restricted, and it is not, leading to an overflow...

[Prof Garth Wells]

I'm pretty sure the issue is in FFC.

[Chris Richardson]

Probably needs a fix in ffc

[Anders Logg (Chalmers)]

Removing milestone: 1.7 (automated comment)

[Jan Blechta]

https://bitbucket.org/fenics-project/ffc/issues/79/subdofmap-of-restricted