Apologies for what is probably and incredibly basic question, but I can't seem to find anything about this in the documentation, and the "help" function isn't helping. Could someone clarify what gfu.vec and gfu.vec.data represent for functions in a CompoundFESpace?
For a non-compound space, I gather that gfu.vec is a BaseVector object which stores the raw coefficient values of gfu in gfu.vec.data. When you work in a compound space, you have a new attribute, gfu.vecs, which as far as I can tell is just a list of BaseVectors.
The thing that confuses me is that GridFunctions in CompoundFESpaces still have a "vec" attribute. What do gfu.vec and gfu.vec.data represent in a compound space? Are they just a convenient concatenation of the individual BaseVectors stored in gfu.vecs, or is there something else going on?