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ElementUnion

 

noreply@xxxxxxxxxxxxx wrote:
------------------------------------------------------------
revno: 1440
committer: Marie E. Rognes <meg@xxxxxxxxx>
branch nick: ffc
timestamp: Sun 2010-03-07 21:32:00 +0100
message:
  Bug fixes in logic wrt unions of mixed elements. Human-readable code
  generated for Mini looks correct now :)
(Don't know about evaluate_basis* and tabulate_tensor*)

FFC is now able to compile ElementUnions. An ElementUnion of a set
of elements represents the span of the union of the finite element bases.
A classic example of its use would be to augment some element space
by the bubble element (cf ffc/demo/Mini.ufl).

Note that it is not really a finite element in the Ciarlet sense,
because the combined basis does not form a nodal basis.
In short, the effect is that one can assemble forms, but
interpolation onto such spaces is not safe.

Some comments:
(a) I'm not convinced that ElementUnion is the perfect name.
(b) Some additions are required for pydolfin to recognize ElementUnions. Hake?
(c) It is not fully tested -> hangs on (b)

--
Marie