[petsc-dev] Mat/DM dependency

[Jed Brown]

Mat does not normally depend on DM, but a couple implementations do,

  $ grep -rl DAGet petsc/src/mat/impls
  petsc/src/mat/impls/hypre/mhyp.c
  petsc/src/mat/impls/adic/nladic.c
  petsc/src/mat/impls/adic/matadic.c

So when these are enabled, all the Mat examples fail to link because
PETSC_MAT_LIB does not include PETSC_DM_LIB.  This is especially
annoying to me because the PETSc builds I use have Hypre enabled,
meaning that I need to keep more special testing builds (without Hypre)
just to be able to run the Mat tests.

Is the HYPREStruct stuff destined to eventually move out of Mat?

Jed