[Trilinos-Users] ilut setting

[Hoang Giang Bui]

Dear Trilinos developers,

Is there difference between 2 settings:

solver_parameters.set("AZ_solver", "AZ_bicgstab")
solver_parameters.set("AZ_kspace", 1000)
solver_parameters.set("AZ_output", 100)
solver_parameters.set("AZ_precond", "AZ_dom_decomp")
solver_parameters.set("AZ_subdomain_solve", "AZ_ilut")
solver_parameters.set("AZ_drop", 0.0)
solver_parameters.set("AZ_ilut_fill", 10.0)
aztec_solver.SetParameters(solver_parameter, true);

And:
solver_parameters.set("AZ_solver", "AZ_bicgstab")
solver_parameters.set("AZ_kspace", 1000)
solver_parameters.set("AZ_output", 100)
solver_parameters.set("AZ_precond", "AZ_none")
aztec_solver.SetParameters(solver_parameter, true);
IFPreconditionerType = "ILUT"
preconditioner_parameters.set("fact: ilut level-of-fill", 10.0);
preconditioner_parameters.set("fact: drop tolerance", 0.0);
overlap_level = 1
mPrec = Teuchos::rcp(Factory.Create(IFPreconditionerType, &rA, 
overlap_level));
mPrec->SetParameters(preconditioner_parameters);
aztec_solver.SetPrecOperator(&*(mpPrec->GetOperator()))

I thought it all resulted in Additive-Schwartz preconditioner with ILUT 
as local subdomain preconditioner. But it gives different performance. 
The first setting works well but the second failed to converge.

Best regards
Giang Bui