User defined basis functions

On 13 June 2012 13:25, Tore Gunnar Halvorsen
<email address hidden> wrote:
> New question #200303 on DOLFIN:
> https://answers.launchpad.net/dolfin/+question/200303
>
> Hello!
>
> I am going to implement a convection-diffusion equation, and I am considering using the Dolfin framework. The catch is that we are going to upwind the test-space, hence we need to be able to define the basis functions in the test space according to the upwinding. These are not standard basis functions, but rather linear combinations of basis functions on a finer mesh.
>
> So, is it possible to user define the basis functions given a mesh and degrees-of-freedom?
>

Yes. You would need to implement the ufc::tabulate_tensor function by
hand. This function simply returns the local element vector or matrix.

DOLFIN doesn't provide any support for basis functions, but you could
use FFC to create a ufc::finite_element, which would allow you to
access standard shape functions, which might be helpful in building
the element vector/matrix.

Garth

> Cheers
>
>
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