[petsc-users] Linear solver diverging

[bichinhoverde]

I have a linear system which I can easily solve using the Pardiso library,
which is a direct solver. But when I try Petsc, the solver does not
converge. It reduces the norm a little but then gets stuck.

I tried several combinations of pc_type and ksp_type. It seems that
pc=jacobi is better, since my linear system does not have the diagonal
element in some rows.

Is there some advice you can give me? Some way to analyse the matrix and
find out why it does not work?
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