dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Wed, Aug 20, 2008 at 08:43:08AM -0600, Ostien, Jakob T wrote:
> Hi,
> 
> I need to be able to assemble an active set of integration points.  Essentially, to determine the set I loop over cells and then loop again over the integration points in the cell and determine if that integration point is active with some criteria.  Then I'd like to be able to assemble that set.
> 
> This is a problem because currently the element_tensor does not break down into integration points, and I need to take derivatives, so the QuadratureElement in FFC is also ruled out.  I suppose I could calculate derivatives and then project on the QuadratureElement, but that seems sort of unclean.
> 
> It seems like the recent discussion about integrating at a point (on the UFC list) might help me out here.
> 
> Any other thoughts on how I might go about this?
> 
> Jake

I don't know yet. I'm thinking about how much of this should go into
the compiler and how much should be left to the user.

We're working on similar things (and I know Garth is too). I think a
common denominator would at least be to be able to evaluate a form at
a given point.

I like Kent's suggestion earlier about adding a new UFC class to go
along with the other three integral classes, something like

  point_integral

with tabulate_tensor taking the coordinates for a point as additional
input.

-- 
Anders

Attachment: signature.asc
Description: Digital signature