[petsc-users] SLEPc - Generalized symmetric eigenproblem using ARPACK

[Jose E. Roman]

El 25/03/2015, a las 21:29, Harshad Sahasrabudhe escribió:

> Hi,
> 
> I'm trying to use the ARPACK interface in SLEPc for calculating smallest eigenvalues with eigenvectors of a generalized eigenproblem. The matrices are symmetric.
> 
> What are the suggested linear solvers/preconditioners for this type of a system when using ARPACK? I am using shift and invert with a shift of 0.
> 
> I get a lot of spurious eigenvalues when I use GMRES linear solver or MUMPS for LU factorization. Chebyshev doesn't seem to converge (I don't have a good guess for the higher end of eigenvalues). 
> 
> Thanks,
> Harshad

With MUMPS you should not get spurious eigenvalues. Did you try the krylovschur solver? How do you know the eigenvalues are wrong? Are you setting problem type to GHEP?

Jose