El 22/05/2013, a las 22:15, Heikki Virtanen escribió: > Hi, I have been trying to solve a generalized eigenvalue problem using > SLEPc's EPS object. I have tried to parallelize my solver, so I should > use PETSc's mpiaij matrices instead of seqaij matrices. > Unfortunately, PETSc's LU preconditioner does not support MPI matrices. > (this is said in the manual and if I use it with mpiaij matrices I > get an error message) I get the eigenvalue problem solved with > LU preconditioner and seqaij matrices but, I also have to use a > spectral transformation ( shift-invert ) to improve convergence. > > But, as I mentioned before I cannot use LU preconditioner with mpiaij > matrices. Thus, I have changed preconditioner to Hypre's BoomerAMG, > for example. ( which supports mpiaij matrices ) When I use this > combination ( BoomerAMG/shift-invert transformation/ > Krylov-Schur solver) I get an early convergence failure after a couple > of iterations. I have also tried other solvers and preconditioners, > (Hypre's pilut, euclid, bjacobi and Jacobi-Davidson solver) but the result is > the same. Without any preconditioner I also get the early convergence > failure and without the spectral transformation convergence is > too slow. Any comments or suggestions? > > -Heikki
Try a parallel LU such as MUMPS. This is mentioned in the manual. Jose
