[petsc-users] Question about KSP

[Jed Brown]

Elias Karabelas <elias.karabelas at medunigraz.at> writes:

> I have a question about preconditioned solvers. So, I have a 
> Sparsematrix, say A, and now for some reason I would like to add some 
> rank-one term u v^T to that matrix.

You can use Sherman-Morrison/Woodbury, but it costs an extra
preconditioner application and Krylov with the old preconditioner
converges in one extra iteration, so it's a wash.  You might prefer it
for repeated solves though.
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