[petsc-users] SLEPc EPSGD: Can not converge, error estimation floats over 1e-6

[Jose E. Roman]

Does it work with -eps_gd_blocksize 1 ?
Why do you want to use GD? JD and GD are best when you need to compute eigenvalues around a target. For your case, I would try with the default solver (Krylov-Schur) or with LOBPCG.

Jose


> El 13 jul 2022, a las 4:59, Runfeng Jin <jsfaraway at gmail.com> escribió:
> 
> Hi!
> I am trying to find 3 eigenvalues of a matrix 81,160*81,160, and it get 0 eigenvalue after  162320 iterations. I use -eps_monitor and find error estimation floats over 1e-6, I didn't set the tolerance so it should be the default 1e-8. Actually it should achieve 1e-10.
> 
> I have tried  JD and GD, both of them can not converge. Does there any ways to help it converge to the 1e-10? 
> 
> By the way, I use default Convergence criterion, the output of  -log_view and -eps_monitor  are shown in attachment.
> Thank you!
> 
> Runfeng Jin
> <eps_monitor-and-log_view.txt>