Dear Firedrakers,
Greetings from Montreal. I'm thinking about a double splitting method to solve the system
(M + D + L)u = f,
which as a preconditioner works out as
(M + D)^{-1}M(M + L)^{-1} r,
where r is a residual.
In the absence of a better idea, I'll implement this through a Python preconditioner. But is there a smarter way to do this?
all the best
--cjc