Hi!

I would like to ask if it is possible to create a MatNest matrix that
contains matrices, vectors and scalars.

My (jacobian) matrix looks like the following

[[A, B, a, b],
 [C, D, c, d],
 [e, f, g, h]]

where A-D are sparse square matrices, a-d are dense column vectors, e,
f are sparse row vectors and g,h are just scalars.

Is there also a petsc4py example that shows how nest objects should be
created and how they should be used?

Best regards
Thomas