On Sat, Feb 25, 2012 at 12:23, Jed Brown <[email protected]> wrote:

I now realize a weakness in my PF transformation suggestion: it doesn't work with vector elements (Raviart-Thomas or Nedelec) or staggered grids. I don't know a way to include that with the ability to transform from conservative to primitive variables. This is unfortunate because many important preconditioning methods operate in different variables than the nonlinear system is defined in.

This is to say, that sort of transformation can't reasonably be _implemented_ using only DM base, it has to be implemented using DMXXXSet* methods.