Non repeatability issue

[Barry Smith]

   Try a ksp_tol of 1.e-14 instead of 1.e-12?

    Barry

On Mar 31, 2008, at 8:11 AM, Aldo Bonfiglioli wrote:
> Barry, Matt
> I am back on the Non repeatability issue with answers
> to your questions.
>
>> 2) did you do the -ksp_rtol 1.e-12 at the same time as the -   
>> vecscatter_reproduce? They
>> must be done together.
>
> The enclosed plot (res_vs_step) shows the mass residual
> history versus the Newton step counter.
>
> For these same runs, the continuation parameter (CFL) shows similar  
> jumps
> being based upon the SER approach, see plot cfl_vs_its.pdf
>
>> When you just fix the CFL and run Newton  runs to completion
>> is it stable?
>
> I have restarted the code from an almost fully converged solution
> using infinite CFL and let it run for 30 Newton steps.
> The behaviour is much more "reasonable" and the solution
> remains within the steady state (see plot restarted....)
>
>> Then if you ramp up the CFL much more slowly is it  stable and Newton
>> convergence much smoother?
>
> I have not tried yet.
> I know there exist smoother strategies
> than SER to rump the continuation parameter
> (I know this
> http://www.cs.kuleuven.ac.be/publicaties/rapporten/tw/TW304.ps.gz
> for instance)
>
>
> Aldo
>
> -- 
> Dr. Aldo Bonfiglioli
> Dip.to di Ingegneria e Fisica dell'Ambiente (DIFA)
> Universita' della Basilicata
> V.le dell'Ateneo lucano, 10 85100 Potenza ITALY
> tel:+39.0971.205203 fax:+39.0971.205160
>
>
> < 
> res_vs_step 
> .pdf><cfl_vs_its.pdf><restarted_from_converged_solution.pdf>