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?
