[petsc-users] what does it mean with "-1.#IND" in solution vector?

[Matthew Knepley]

On Mon, May 30, 2011 at 7:51 AM, Longmin RAN <longmin.ran at gmail.com> wrote:

> Dear all,
>
> I'm using ksp with external superlu package to solve my linear systems. The
> system is sparse, real and symmetric, I'm expecting unique solution with
> normal values. However, the KSPSolve returned with error 0, but the norm of
> error is "1.#QNAN", and in the solution vector some values are "-1.#IND".
> What does this mean ? Any help is appreciated. Thanks.
>

You generate  a NaN somewhere. I usually check for this using norms, since
NaN propagate. Check the norm
of the rhs, initial solution, matrix, etc.

   Matt


> Cheers,
>
> Longmin
>



-- 
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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