Hamed, On Wednesday, October 19, 2016 at 10:25:37 AM UTC-4, Hamed Babaei wrote:It seems that I've been choosing wrong solver for my problem. Since my problem has some sort of instability in its nature, > > although my system_matrix is symmetric, it is not necessarily positive > definite. So I have two questions: > First, Is there any function in Dealii or Petsc to compute the determinant > of system_matrix. I have used a determinant function for 3*3 matrices and > it doesn't work for higher dimensions. > Why do you need this?
> Second, which solver and preconditioner can be used for symmetric but > non-positive definite system_matrix. > For the solver, you can use GMRES, BiCGSTAB, or MinRES. For the preconditioner, you can use ILU, SSOR, or algebraic multigrid (AMG). Sometimes AMG have difficulties with non-s.p.d. matrices though. 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.
