[petsc-users] DIVERGED_DTOL with SNES after switching to 3.8

[David Knezevic]

That works, thanks!

David

On Sat, Oct 28, 2017 at 10:44 AM, Smith, Barry F. <bsmith at mcs.anl.gov>
wrote:

>
>   Run with something like   -snes_divergence_tolerance 1e20
>
>   Barry
>
>
>
>
>
>
>
> > On Oct 28, 2017, at 9:31 AM, David Knezevic <david.knezevic at akselos.com>
> wrote:
> >
> > Hi all,
> >
> > I updated to the head of the maint branch (b5b0337). Previously (with
> version 3.7), I had a SNES test case that converged like this:
> >
> >   NL step  0, |residual|_2 = 9.074962e-03
> >   NL step  1, |residual|_2 = 5.516783e+03
> >   NL step  2, |residual|_2 = 1.370884e-12
> > Number of nonlinear iterations: 2
> > Nonlinear solver convergence/divergence reason: CONVERGED_FNORM_RELATIVE
> >
> > and now I get the following behavior:
> >
> >   NL step  0, |residual|_2 = 9.074962e-03
> >   NL step  1, |residual|_2 = 5.516783e+03
> > Number of nonlinear iterations: 1
> > Nonlinear solver convergence/divergence reason: DIVERGED_DTOL
> >
> > I didn't change anything in my code, so I guess the default DTOL options
> in SNES have changed? If someone could suggest how I can recover the old
> behavior, that'd be great.
> >
> > (Note that this is a contact problem using an augmented Lagrangian
> penalty method, so the convergence is pretty nasty and it's hard to avoid
> these large jumps in the residual, so I don't want to get the DIVERGED_DTOL
> error in this case.)
> >
> > Thanks,
> > David
>
>
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