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
