On Wed, Mar 21, 2018 at 3:35 AM, 我 <[email protected]> wrote:
> Hi,
> I want to compare the time cost between preconditioner and
> unpreconditioner in PETSc. But I didn't know how to turn off the
> preconditioner in Petsc. If I choose the PCNONE, but the solution even can
> not converge.
>
That is how you turn off a preconditioner, -pc_type none. Without a
preconditioner, almost nothing converges. You can't have it both ways.
Thanks,
Matt
> If I do not declare PC at the beginning of my program, will PETSc choose a
> default preconditioner? I just want to turn off it. Any suggestions?
> Thank you very much!
> Daye
>
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--
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/>
