[petsc-dev] Matrix-free preconditioners

[Chris Eldred]

Hey Petsc Dev,

I had some questions about preconditioners, and I was hoping the list
could help me out. Specifically, if I have a MatShell with the ability
to compute the diagonal of the matrix; and a geometric multigrid
hierarchy with appropriate operators defined; what are my
preconditioner options?

>From reading the manual and the doc pages, it appears that my options are
1) Jacobi (and block variants)
2) Multigrid
plus the ability to use Fieldsplit for block matrices. Then within
multigrid, any iterative KSP (ie one that requires only matrix-vector
products) can be used as a smoother, with the basic ones being
Chebyshev and Richardson using Jacobi as a preconditioner.

Is this correct? Is there anything else?

Regards,
Chris Eldred

-- 
Chris Eldred
https://www.math.univ-paris13.fr/~eldred/
Postdoctoral Fellow, LAGA, University of Paris 13
PhD, Atmospheric Science, Colorado State University, 2015
DOE Computational Science Graduate Fellow (Alumni)
B.S. Applied Computational Physics, Carnegie Mellon University, 2009
chris.eldred at gmail.com