ffc team mailing list archive

[Andy Ray Terrel <andy.terrel@xxxxxxxxx>]

Okay I see.  Its just a third order bubble, sometimes I send mail
before I think.  The mini element is a first order bubble or at least
that's what Brezzi Fortin say.

-- Andy



On Fri, Apr 9, 2010 at 8:43 PM,  <meg@xxxxxxxxx> wrote:
>> Is there anything telling how the bubble functions are defined?
>>
>> For example with the Mini example:
>>
>> P1 = VectorElement("Lagrange", "triangle", 1)
>> B = VectorElement("Bubble", "triangle", 3)
>> Q = FiniteElement("Lagrange", "triangle", 1)
>> Mini = (P1 + B) * Q
>>
>> Does B consist of 3 bubble functions in some symmetric pattern in the
>> element?
>>
>
> The bubble functions are the bubble functions ;)
>
> In the above example, B is the span of the piecewise continuous
> cubic functions that are zero on the boundary of each triangle.
> (1 per triangle for a FiniteElement and hence 2 per triangle for a
> VectorElement of value dimension 2.)
>
> In general, the bubble finite element of degree k is the span of the interior
> basis functions of CG_k.
>
> --
> Marie
>
>
>