bilinear form boundary integration for two different FESpaces

Hi,

I was trying to build a bilinear form with two different FESpaces (in use for postprocessing the solution), like but there is a bug concerning the boundary integration.
1, Other() didn't work for element_boundary integration
2, skeleton-based integration didn't work.

E.g., attached code shall return me a vector of ones, but it returns zero vector instead.


Best,
Guosheng

Dear Guosheng,

Indeed, mixed bilinear forms are simply not yet implemented for element_boundary or skeleton-integrators.

A work-around for now could be to set up the larger matrix for the product space and work with it.

Best,
Christoph