On Tue, Aug 14, 2012 at 5:03 PM, Barry Smith <[email protected]> wrote:

But you've just told me that ONLY ts is allowed to use the SNESSetJacobian() context slot (coloring and presumably users) aren't allowed to.

Not at all. I mean that coloring as produced internally by SNES should not ascribe special meaning to that field being NULL or not. You could perhaps have -snes_fd_color create an empty coloring object and put it into the callback slowt. We should perhaps support destructors for function/Jacobian contexts.