Am 12.06.2012 15:04, schrieb Jed Brown: > On Tue, Jun 12, 2012 at 7:56 AM, Thomas Witkowski > <thomas.witkowski at tu-dresden.de > <mailto:thomas.witkowski at tu-dresden.de>> wrote: > > There should be no null space from the Cahn-Hilliard equation. > > > You said all those boundary conditions are either Neumann or periodic. > I guess it couples to the fluid variables without any null space? yes. > > Is there some black-box preconditioner that does not relay on LU > factorization at some point? I know that black-box approaches are > mostly not efficient, but I would have something I can work with. > > > The SVD always works and will tell you about a null space, but of > course it's very expensive. So assume I have a basis for the null space of the system that should be solved. Is there any block-box solver/preconditioner approach that does not make use of (I)LU factorization at any point?
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