[petsc-users] Incorrect eigenvalues

[Jose E. Roman]

> El 18 jul 2016, a las 21:48, Hassan Md Mahmudulla <mhassan at miners.utep.edu> escribió:
> 
> Would you please give me an idea what combination of ksp solver and preconditioner I should use to solve this generalized symmetric hermitian problem? To get the convergence faster, do I need to use external solvers like mumps and superlu_dist?
> 
> Thanks
> M Hassan

For computing eigenvalues in an interval, you have to follow exactly what is written in section 3.4.5 of SLEPc's users manual. It is not possible to use preconditioners in that case. Also, superlu_dist cannot be used for this, only MUMPS or PETSc's cholesky (sequential).

Jose