Michal, Le ven. 19 oct. 2018 à 06:33, Michał Wichrowski <mtwichrow...@gmail.com> a écrit : > 1) The number of iterations and residual are obviously strange. I guess that > ARPACK solver does not update SlolverControl object That's correct. SolverControl is used to set ARPACK's parameters but it is not updated by ARPACK so the number of iterations and the residual are garbage.
> 2) The largest eigenvalue is computed instead of the largest one, and, I > guess, the smallest eigenvalue is computed instead of the largest one. If you use ARPACK through deal without patching it, then the only method available is shift-inverse. The thing is that when you know the largest eigenvalue of the inverse you can get the smallest eigenvalue of the operator. So yes, the names are reversed. > 3) I get complex eigenvalues in some cases and I am quite sure, that all > eigenvalues of the system are real. I've not had this problem. Maybe it's because of numerical error? > I noticed that in some cases the "smallest" eigenvalue does not match maximum > eigenvalue obtained from power method. Are you sure that the power method has converged? Also, try using ARPACK's regular mode instead of shift-inverse. I think it might be better to find the largest eigenvalue. Best, Bruno -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
