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
