[petsc-users] KSP no longer returning NaNs?

Barry Smith bsmith at mcs.anl.gov
Wed Jul 25 16:58:18 CDT 2012

  As always a COMPLETE error report is useful. There are a million ways you could see this change in behavior but we can't spend time guessing.  At a minimum please send the entire error output.  

   I note in 3.3 the KSPDefaultConverged() still checks for NAN and returns a negative converged reason (not an error) so I can only guess why you are getting different behavior without more information.,


On Jul 25, 2012, at 4:35 PM, Kirk, Benjamin (JSC-EG311) 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?
> Thanks,
> -Ben

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