On Tue, Mar 29, 2011 at 15:29, Thomas Witkowski < [email protected]> wrote:

Is there any example which makes use of it?

src/snes/examples/tutorials/ex28.c is a (contrived) multi-physics prototype that uses MatNest tranparently if you run with -pack_dm_mat_type nest (currently, you should add -pc_type fieldsplit -pc_fieldsplit_type additive because off-diagonal blocks are not automatically preallocated). There are also two tests that use the low-level API: $ grep -l MatNest src/**/tests/*.c src/ksp/ksp/examples/tests/ex22.c src/snes/examples/tests/ex17.c