[Pw_forum] real space non-local pseudopotential projectors

[Nicola Marzari]

Dear Nichols,

We don't really have much experience with PWSCF and very large systems,
but 1000 atoms with CP (inside quantum-espresso) seems doable (of 
course, it depends on how many electrons you have).

Note that the CP steps mentioned below are damped dynamics -
CVS CP can now do the ground state relaxation with conjugate-gradients, 
as well, that is more efficient (in practice, even if in theory they are
comparable).

------
On 8 dual-xeon motherboards, 3.4 GHz (16 cpu, although the second CPU on
each motherboard is close to useless):

PWSCF
(10,10) CNT -  (49bohr*49*14 , 125 atoms, 3 k-points)
electronic relax - 3 hours
ionic relax - it really depends on the initial configuration. Between
5 and 10 days.

CP
(10,10) CNT - (43bohr*43*37,  325 atoms)
electronic relax - 17 hours (310 damped dynamics steps)
--------
On 4 PIV 3.2 GHz

CP
(5,5) CNT - (36bohr*36*56, 248 atoms,  )
electronic relax - 44 hours (260 damped dyanmics steps)

On the same machine (4 PIV, 16GB) a spin-unpolarized
protein, with ~340 atoms, took ~10 minutes per CP step.
--------

Let us know what you get !

Best,

			nicola


Nichols A. Romero wrote:

> Hi,
> 
> Does PWSCF use real space non-local pseudopotential projectors using
> the method of King-Smith et. al?
> 
> What are the largest system that people have treated using PWSCF?
> Given excellent computer resources, could it handle 1000 atom systems
> (lighter elements)?
> 
> Thanks,
> --
> Nichols A. Romero, Ph.D.
> 1613 Denise Dr. Apt. D
> Forest Hill, MD 21050
> 443-567-8328 (C)
> 410-306-0709 (O)
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Prof Nicola Marzari   Department of Materials Science and Engineering
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