[petsc-users] KSP no longer returning NaNs?

Jed Brown jedbrown at mcs.anl.gov
Wed Jul 25 19:03:26 CDT 2012

On Wed, Jul 25, 2012 at 6:35 PM, Sean Farley <sean at mcs.anl.gov> wrote:

> You mention in your first email that checking for NAN is due to your
> timestep; perhaps an alternative route would be to use the newer TS
> code which has some adaptive options, namely:
>   -ts_max_snes_failures <1>: Maximum number of nonlinear solve
> failures (TSSetMaxSNESFailures)
>   -ts_max_reject <10>: Maximum number of step rejections before step
> fails (TSSetMaxStepRejections)
>   -ts_adapt_dt_min <1e-20>: Minimum time step considered
> (TSAdaptSetStepLimits)
>   -ts_adapt_dt_max <1e+50>: Maximum time step considered
> (TSAdaptSetStepLimits)
>   -ts_adapt_scale_solve_failed <0.25>: Scale step by this factor if
> solve fails ()

These options are only relative to SNESConvergedReason. The "problem" is
that PetscError is being called. If NaN arising in the solver is not an
"error", just a "did not converge", then we can't be calling PetscError.
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