[petsc-users] A number of questions about DMDA with SNES and Quasi-Newton methods

[zakaryah .]

I tried -snes_compare_explicit, and got the following error:

[0]PETSC ERROR: Invalid argument

[0]PETSC ERROR: Matrix not generated from a DMDA

What am I doing wrong?

On Tue, Oct 3, 2017 at 10:08 AM, Jed Brown <jed at jedbrown.org> wrote:

> Barry Smith <bsmith at mcs.anl.gov> writes:
>
> >> On Oct 3, 2017, at 5:54 AM, zakaryah . <zakaryah at gmail.com> wrote:
> >>
> >> I'm still working on this.  I've made some progress, and it looks like
> the issue is with the KSP, at least for now.  The Jacobian may be
> ill-conditioned.  Is it possible to use -snes_test_display during an
> intermediate step of the analysis?  I would like to inspect the Jacobian
> after several solves have already completed,
> >
> >    No, our currently code for testing Jacobians is poor quality and
> poorly organized. Needs a major refactoring to do things properly. Sorry
>
> You can use -snes_compare_explicit or -snes_compare_coloring to output
> differences on each Newton step.
>
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