On Thu, 30 Jun 2011, Truman Ellis wrote:
> How do I access neighbor information using
> the DiffSystem framework,
FEMContext::elem>neighbor(FEMContext::side) is the neighboring
element.
> specifically to calculate jumps and averages for calculating fluxes?
Currently that's only possible by doing things the same way as
nonDiffSystem codes: build a new FEBase (you can get the right type
from the FEMContext), initialize it on the neighbor with the
inverse_map'ed xyz values that the first FEBase gave you, and
calculate values and gradients from that.
It would probably be straightforward to fold that code into
FEMSystem/FEMContext in the library, though, with a pervariable
boolean to determine which variables needed jump information... my
suggestion would be to start with it in user code for this DG Poisson
system you're trying to get familiar with the APIs, then we'll move it
to library code and use that trial system for regression testing, and
then you'll have the facility already up and will have the same
capability already available for more complex formulations.

Roy
