[petsc-users] Problem: Preconditioning of non-daigonally dominant matrix

[panourg at mech.upatras.gr]

Dir All

I have a problem with converging of large block sparse non-diagonally
dominant matrix. Which preconditioner is the best choice for these
systems?
When the diagonal blocks of matrix have more large values by
off-diagonal(diagonally dominant) then the ILU prec gives good results but
when the diagonal blocks have values smaller than off diag. then i cant
take convergence with ILU or other classic preconditioner. Have anyone the
same problem and what did?



K.Panourgias