[petsc-users] ASM vs GASM

Griffith, Boyce Eugene boyceg at email.unc.edu
Mon Apr 29 19:10:32 CDT 2019

I am trying to setup a GASM preconditioner and am running into some difficulty getting convergence even with exact subdomain solvers. I am just doing things in serial now, and tried switching to ASM, and get convergence. I am wondering if I am misunderstanding the GASM interface. If inner_ises and outer_ises define the “inner” and “outer” subdomains for GASM, should GASM and ASM do the same things when configured via:

	PCGASMSetSubdomains(pc, n_subdomains, inner_ises, outer_ises);


	PCASMSetLocalSubdomains(pc, n_subdomains, outer_ises, inner_ises);


— Boyce

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