[petsc-users] DIVERGED_FNORM_NAN

[Matthew Knepley]

On Wed, Sep 16, 2015 at 8:28 AM, Alexander Lindsay <adlinds3 at ncsu.edu>
wrote:

> Hi all,
>
> I've built a MOOSE application and the problem I'm studying solves great
> using serial LU. However, when I try to solve in parallel using super LU, I
> encounter many DIVERGED_LINE_SEARCH errors using the default bt line
> search. If I switch to line_search=none, then instead of
> DIVERGED_LINE_SEARCH errors I get DIVERGED_FNORM_NAN errors. I do not have
> a lot of debugging experience, but I am slowly gaining more. Is there a
> good way to get more information about what's causing the NAN's? I.e. a
> specific residual or jacobian statement?
>
> This may not even be an appropriate list to post this problem in (could be
> more on the MOOSE side); apologies if that's the case.
>

The NaN means something has gone wrong. However, there are a few
SuperLU_dist bugs that we know of. You could try:

  - Upgrading PETSc to the latest patch, which should download the fixed
SuperLU_dist

  - Trying MUMPS instead

  Thanks,

     Matt


> Alex
>



-- 
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
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