[petsc-users] Differences between jacobi and bjacobi preconditioner for cg method 1-processor/block

[Jonathan Wong]

I'm running into an issue for a symmetric (may not be pd) finite element
problem where I am using the cg method and getting an indefinite_mat or
indefinite_pc error using the jacobi preconditioner. If I change the pc
type to bjacobi, it converges nicely. I am only using 1 process, and I
assumed they would produce the same result, as I'm using default options.

Does anyone have any ideas why this would happen?

It also works fine with gmres + jacobi pc.

Thanks,
Jon
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