[gpaw-users] Speeding up calculation for DFT/MD?

[Toma Susi]

On 22.4.2013, at 18.09, gpaw-users-request at listserv.fysik.dtu.dk wrote:
> 
> Message: 2
> Date: Mon, 22 Apr 2013 15:37:44 +0200
> From: Ask Hjorth Larsen <asklarsen at gmail.com>
> Subject: Re: [gpaw-users] Speeding up calculation for DFT/MD?
> To: Lars Smykalla <lars.smykalla at physik.tu-chemnitz.de>
> Cc: gpaw-users <gpaw-users at listserv.fysik.dtu.dk>
> 
> 2013/4/22 Lars Smykalla <lars.smykalla at physik.tu-chemnitz.de>:
>> Hello,
>> 
>> sorry for interfering.
>> 
>>> and be sure to use xc='oldLDA' or 'oldPBE' if you can as
>>> this is much faster than the default libxc implementation.
>> 
>> What is the difference to the default PBE?
>> Will oldPBE give the same energy but just faster?
>> 
>> 
>> Greetings,
>> Lars
> 
> They are just implementations outside libxc.  libxc is extremely slow.
> 
> There may a very small difference due to numerics.
> 
> Regards
> Ask
> 

Hi,

Does this mean one should ALWAYS use oldPBE instead of PBE, or just to speed up calculations?

-Toma