[QE-users] niter_cg_restart parameter in cp.x

[Riccardo Bertossa]

Hi Zeeshan,

this is an internal parameter of the CG algorithm. The iterations are CG 
iterations, not verlet or anything else. A restart/reset in the CG means 
that the algorithm forgets the previous minimization directions and 
starts again minimizing the function in the gradient direction, as in 
the first step.

If you want to do a CG every N steps of the dynamics you can do a 
restart or use the autopilot module.


best regards,

Riccardo Bertossa

SISSA

On 14/02/19 07:49, Zeeshan Ahmad wrote:
> Hi all,
>
> The explanation for ’niter_cg_restart’ parameter belonging to cp.x input in docs is:
>
> “frequency in iterations for which the conjugate-gradient algorithm for electronic relaxation is restarted” with a  default value of 20.
>
> Does this mean for all types of electron_dynamics like ’none’, ‘verlet’, ‘damp’ etc., conjugate gradient algorithm will be used to converge the wave function every 20 steps by default?
>
> Thanks,
> -Zeeshan
>
> --
> Zeeshan Ahmad
> PhD candidate, Mechanical Engineering
> Carnegie Mellon University
>
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