[CP2K-user] Slow calculating speed of HSE06
Matt W
mattwa... at gmail.com
Fri Apr 9 13:09:07 UTC 2021
I hadn't seen the earlier messages in another thread. At a quick glance
your input looks fine. I'd decrease EPS_DEFAULT to 10^-14 or something to
be sure things were set up accurately. Make sure you restart from a GGA
converged solution.
It will, of course, get more expensive for bigger cells but in the limit of
really big cells only linearly with sytem size.
CELL_OPT can be quite expensive with hybrids. You could just do a volume
sweep with static calcs as you have a cubic cell.
Matt
On Friday, April 9, 2021 at 1:31:02 PM UTC+1 ma... at gmail.com wrote:
> Dear Matt,
>
> Yes, I know GAMMA point for such a small system doesn't make sense. I did
> this calculation just for exercise because I thought small system will save
> time. I thought a small system already took such a long time, the larger
> system would take much longer. But based on your description, it seems what
> I though is totally wrong. I would run some large supercell systems later.
> Thanks!
> By the way, regarding the attached input file that I used, could you
> please have a look when you are free and provide some suggestions that may
> improve the performance (e.g., speed and stability) based on your expertise?
>
> Thanks & Regards,
> Hongyang
>
> 在2021年4月9日星期五 UTC+10 下午10:12:47<Matt W> 写道:
>
>> You can't run an 8 atom system without k-points, it doesn't make sense
>> and you can't run hybrid functionals with k-points at the moment.
>>
>> Absolute minimum is a 64 atom system (still nowhere near converged). For
>> the HSE screened exchange, I'd suggest you wil need box dimensions of _at
>> least_ 1 nm on each side otherwise strange things will happen.
>>
>> If ADMM is working well the extra cost of going to bigger systems will
>> not be too big. Plane wave code will be more efficient for the smallest
>> cells, but CP2K should win out for bigger defect cells.
>>
>> Matt
>>
>> On Friday, April 9, 2021 at 9:47:52 AM UTC+1 ma... at gmail.com wrote:
>>
>>> Hi,
>>>
>>> I'm a beginner of using cp2k7.1. My aim is to use HSE06 to calculate the
>>> Si (8 atoms) system. However the calculating speed is extremly slow. I used
>>> OT and ADMM approaches and GAMMA point with 48 cores, but this CELL_OPT
>>> calculation took around 30 mins to finish. As a comparison, I used VASP to
>>> run the same geometry with HSE06 and with only 1 core, the calculation
>>> finished in 50 seconds... So clearly, I must did something wrong in the
>>> input file resulting in a significant limitation in the calculating speed
>>> but I couldn't figure out which part is wrong. Could somebody please
>>> provide some help? Thanks.
>>>
>>> Regards,
>>> Hongyang
>>>
>>
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