ffc team mailing list archive

["Johan Hoffman" <jhoffman@xxxxxxxxxx>]

>
> On Wed, 13 Aug 2008, Jed Brown wrote:
>
>> On Wed 2008-08-13 17:37, Shawn Walker wrote:
>>> ok, but how would you adjust the xml mesh format?  That should be
>>> figured
>>> out first.  I was thinking one could just add extra data for each cell
>>> that specifies the location of the other control points for the
>>> triangle
>>> sides.  Or maybe it would be better to just supply a finite element
>>> function (2nd order or higher) for the x,y,z coordinates of the mesh
>>> and
>>> do it that way?
>>
>> I'm a fan of storing coordinates just like any other function, but you
>> probably want variable order (p-adaptivity) for this since you would
>> like most elements to have an affine mapping (for efficiency and to
>> improve the accuracy of the quadrature).
>
> Well, if DOLFIN has p-adaptive functions built into it, then this would
> not be a problem.  If it doesn't have it yet, then it could wait.  In the
> meantime, I would just have a full P2, or P3 (2nd or 3rd order) function
> for all triangles.  And, in addition, provide a boolean function on each
> cell that says whether it is straight or not.

I am also interested in curved boundaries. If we do not want to change the
xml format, maybe it would be enough to use a boolean MeshFunction over
the boundary to achieve what you describe?

/Johan