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KSP/PC choice

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@xxxxxxxx, tim@xxxxxxxxxxxxxxxxxxx      Fax   +49-421-218-4236

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