[petsc-users] KSP no longer returning NaNs?

[Matthew Knepley]

On Wed, Jul 25, 2012 at 4:35 PM, Kirk, Benjamin (JSC-EG311) <
benjamin.kirk-1 at nasa.gov> wrote:

> Hello -
>
> I've been using PETSc 3.1 for quite a while now and have been hesitant to
> upgrade because of some new behavior I found in 3.2.  Let me explain...
>
> In petsc-3.1, if the KSP encountered a NaN it would return it to the
> application code.  We actually liked this feature because it gives us an
> opportunity to catch the NaN and attempt recovery, in our case by
> decreasing
> the time step and trying again.
>
> It seems in petsc-3.2, however, that PETSc itself aborts internally, so we
> are unable to recover from the situation.
>
> Is there any way to get the old behavior back?
>

1) How exactly could the KSP generate a NaN if it was not injected in A or
b?

2) You can always check the return value of KSPSolve() and do what you did
last time.

   Matt


> Thanks,
>
> -Ben
>
>


-- 
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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