KSP/PC choice

[gaatenek at irisa.fr]

Dear Tims,
Do you monitoring the convergence? Try it a see if you have stagnation in
your convergence.
However you can  try this setting,
 -ksp_type gmres
 -ksp_gmres_restart 30
 -pc_type asm
 -pc_asm_overlap 2
 -sub_pc_type ilu
 -sub_pc_factor_zeropivot 0
 -sub_pc_ilu_levels 3
Regards,




> Dear all,
>
> the more KSP and PC methods are available, the more difficult it is to
> choose a suitable one.
>
> I want to compute Navier-Stokes (using Finite Elements) for
> medium-sized Reynolds numbers (still laminar, though).  I am currently
> using
>
> -ksp_type gmres
> -ksp_gmres_restart 30
> -pc_type bjacobi
> -sub_pc_type asm
> -sub_pc_asm_overlap 2
> -sub_sub_pc_type ilu
> -sub_sub_pc_factor_zeropivot 0
> -sub_sub_pc_ilu_levels 1
>
> but with a large number of CPUs (e.g. 20), no convergence is achieved.
> Does anyone have some suggestions for a better setting?
>
> I am using petsc-2.3.0.
>
> Best Regards,
>
> Tim
>
> --
> Dr. Tim Kroeger                            Phone +49-421-218-7710
> tim at mevis.de, tim at cevis.uni-bremen.de      Fax   +49-421-218-4236
>
> MeVis Research GmbH, Universitaetsallee 29, D-28359 Bremen, Germany
>
> Amtsgericht Bremen HRB 16222
> Geschaeftsfuehrer: Prof. Dr. H.-O. Peitgen
>
>