[petsc-users] Solutions different after program restart

[Jed Brown]

On Sun, Jun 3, 2012 at 9:09 AM, Niceno Bojan <bojan.niceno at psi.ch> wrote:

> Well, even above that, around 50 :-)
>
> You were right.  Reducing 50 by a factor of 0.001, which I set, the
> differences are indeed smaller than the solver tolerance :-)
>

Good


>
>
> But, allow me to ask one more time, to make sure:  I am using gmres with
> Jacobi's preconditioner.  The run is sequential, the nodes are not
> renumbered.  Is it safe to neglect these differences, even if they are
> smaller than prescribed tolerances?
>

It's "safe" in the sense that both answers are equivalent, but it would be
good to know what is causing the differences. How is the matrix assembled?
Did you use -ksp_view_binary and ksp ex10 to check that the system really
is identical? Does ksp ex10 give the same output each time you run it? Can
you send a few iterations of output from -ksp_monitor_true_residual?
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