[petsc-users] Implementing a homotopy solver

Matthew Knepley knepley at gmail.com
Wed Jul 18 09:55:38 CDT 2018

On Tue, Jul 17, 2018 at 1:32 PM zakaryah <zakaryah at gmail.com> wrote:

> Thanks Matt.
>>> 2) Is there a way to reuse the KSP for (1) to efficiently solve (2),
>>> given the method which answers question 1) ?
>> Not really, unless you use some type of factorization for the
>> preconditioner.
> Can you elaborate?
> ​I know that KSP can efficiently solve linear systems with the same matrix
> but different right-hand sides, just by calling KSPSolve successively.
> Will this be impossible within the nonlinear solver after calculating the
> nullspace?​
This is what I was referring to. KSP reuse only works if you have some
factorization preconditioner. In that case, KSP
will keep it around if you call KSPSolve() again with a different rhs. You
can do that same thing in your case.


What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
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