[petsc-users] MatType BAIJ and Jacobi preconditioner

[Jed Brown]

"Kirk, Benjamin (JSC-EG311)" <benjamin.kirk-1 at nasa.gov> writes:

> I've got a BAIJ matrix with block size 5 for a compressible flow
> application.
>
> I am curious, when using -pc_type Jacobi what is actually applied as
> the "diagonal" in the preconditioner?
>
> That is, for block matrix K, I assume the Jacobi preconditioner
> extracts the diagonal values K_ii, but is this the scalar diagonal, or
> the 5x5 block-diagonal matrix?

-pc_type jacobi : scalar diagonal

-pc_type pbjacobi: point-block diagonal (the 5x5 blocks)