[petsc-users] a preconditioner question

[SUN Chun]

Hi Petsc Developers,

I was using a preconditioner of ASM with subpc ILU, (outside KSP is BCGS). I have an impression that ASM is somewhat close to block-Jacobi in a parallel sense. Then I was thinking to do multiple preconditioning for the whole system to increase the convergence behavior on the boundary equations. However I can't find any options that I can increase the "passes" of preconditioner usage. 

I was also trying "-pc_type composite", then specifying "-pc_composite_pcs asm,asm", and "-sub_pc_type ilu", this gave me error of ilu can not run in parallel. But I was intended to run ilu as sub_pc inside each domain.

I'm not sure if my idea makes sense or I missed something in the manual.

Thanks for the help.
Chun


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