We are pushing the bounds of -snes_fd and I wanted to understand what we can expect. We do not use a DM. I assume FD has to apply the operator N times. I don't see how you can color unless we give SNES a graph (in a DM). Am I missing something?
If not, I could construct a symmetric matrix that would be, I think, a "safe" graph to use for coloring. Is there an method (or example code) to get SNES to use that for a coloring? Like a DM constructor that takes a graph in a Mat.
