[CP2K-user] Slow calculating speed of HSE06

[Matt W]

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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