[CP2K-user] Slow calculating speed of HSE06

[Matt W]

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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