I was wondering whether any of you knew if FENICS has the capability to solve coupled 1D-3D problems that are linear non-iteratively? As an example, pipes embedded in a porous domain will provide pressure sources (at their terminal ends) to the Darcy equation. This can be solved with a linear solver if I can concatenate the finite element matrix with the Poiseuille flow in the pipes. I can't quite see how to do this in FENICS, if it is at all indeed possible. Any suggestions, or directions towards more appropriate forums, would be massively appreciated.