[petsc-users] SNES always ends at iteration 0

[Mark Adams]

The three "tol" values should be finite. It sounds like you set them to 0.
Don't do that and use the defaults to start.
The behavior with zero tolerances is not defined.
You can use -snes_monitor to print out the iterations.

On Sun, Dec 12, 2021 at 6:22 PM celestechevali at gmail.com <
celestechevali at gmail.com> wrote:

> Hello,
>
> I encountered a strange problem concerning the convergence of SNES.
>
> In my recent test runs I found that SNES always stops at iteration 0...
>
> At first I thought there may be an error with the tolerance setting, so I
> output the tolerances :
>
>
>
> *atol = 0.000000, rtol = 0.000000, stol = 0.000000, maxit = 50, maxf =
> 10000  Norm of error 760.491 Iterations 0*
>
> Which are exactly the default values that I always used. However, for the
> same tolerance settings, the SNES solver converges successfully if I
> decrease the number of degrees of freedom in my system...
>
> I wish to know if anyone has experienced the same type of problems or has
> an idea about what could possibly cause the problem...
>
> Thank you so much in advance.
>
> I appreciate any advice that you provide.
>
>
>
>
>
>
>
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