[petsc-users] "Must select a target sorting criterion if using shift-and-invert"

[Matthew Knepley]

On Fri, Oct 20, 2017 at 7:43 PM, Kong, Fande <fande.kong at inl.gov> wrote:

> Hi All,
>
> I am trying to solve a generalized eigenvalue problem (using SLEPc) with
> "-eps_type krylovschur -st_type sinvert". I got an error message: "Must
> select a target sorting criterion if using shift-and-invert".
>
> Not sure how to proceed.  I do not quite understand this sentence.
>

You need to know how to choose the shift. So for instance you want the
smallest eigenvalues, or the closest to zero, etc.
I don't know the options, but they are in the manual.

   Matt


>
> Fande,
>



-- 
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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