Dear Jed,

I will try to answer your questions. I've started a calculation with the -eps_view and -log_view and send you the output once it is done.

On Wed, Dec 28, 2016 at 4:42 PM, Jed Brown <jed@jedbrown.org> wrote:
Vijay Gopal Chilkuri <vijay.gopal.c@gmail.com> writes:


How sparse is your matrix, where does it come from (affects spectrum and
thus convergence rate),

The matrix is a variant of the Double Exchange model Hamiltonian. It has at most 48 non-zero elements per row.
 
how many eigenvalues did you request, and what
preconditioner did you use? 

I requested for 2 eigenvalues. I used the krylovshur solver from the SLEPc package with the default preconditioner. 

I'm curious about the preconditioner thing. Can you suggest some suitable for my system ?

Thanks a lot !
 Vijay
 
Sending the output of running with
-eps_view -log_view is necessary to start understanding the performance.

> I have two questions:
>
> 1. Is this time reasonable, if not, is it possible to optimize further ?
>
> 2. I've tried a quick google search but could not find a comprehensive
> benchmarking of the SLEPc library for sparse matrix diagonalization. Could
> you point me to a publication/resource which has such a benchmarking ?
>
> Thanks for your help.
>
> PETSc Version: master branch commit: b33322e
> SLEPc Version: master branch commit: c596d1c
>
> Best,
>  Vijay