[CP2K-user] [CP2K:20725] Re: out of memory: C3N4 (56 atoms) HES06 + RI-HFX + ADMM

[Augustin Bussy]

Hi Jiang,
I was able to run your input file on a 512G system, but I'd like to add a 
few comments:
1) I somehow missed the fact that you are running RI-HFX with K-points. In 
such a case, the choice of the RI metric is not crucial for performance (or 
memory usage), and the best course of action is to keep the default.
2) What really matters is the number of atoms in the unit cell, the 
diffuseness of the basis set, and the range of the HFX potential. There is 
not much you can do here, especially since you already use ADMM. The range 
of the HFX potential really matters, because this influences how many 
periodic images of your system need to be considered. Typically, this  has 
a limited impact for 2D systems, because there should only be images along 
the XY axes. However, if the extent of the cell in the Z direction is too 
short, periodic images get involved as well. *I found that increasing the Z 
cell parameters from 20 Ang to 30 Ang speeds up the calculations by a 
factor 2*, because less images are needed.
3) Unless you reach a very high number of K-points (~1000), this has 
practically no impact on cost, and only a little on memory. You might as 
well use a denser grid than 3x3x1
4) I am not sure if your system is a metal. If it is not, you should avoid 
using Broyden mixing and smearing, as SCF convergence slows down.
5) While you can run this calculation on a single HPC node with 512G, this 
will be extremely slow. I highly recommand using more resources, and 
increasing the KP_NGROUPS keyword the the HF%RI section. This is not a 
small calculation you are attempting.

I invite you to read the paper written for the method: 
https://doi.org/10.1063/5.0189659, this might help you understand some of 
the points above.
I hope that helps. Best,
Augustin
On Wednesday 18 September 2024 at 16:54:17 UTC+2 yj jiang wrote:

> Thank you all very much for your help. A few days ago, I thought I had 
> uploaded the output file here, but it seems that due to the large file 
> size, the upload may not have been successful. I apologize for this.
>
> Yesterday, I seemed to have found the reason. The supercomputing job 
> system I am using has a memory allocation limit for each process, and this 
> issue is not exclusive to cp2k jobs. I am now planning to set the maximum 
> memory usage for cp2k to see if it resolves the problem.
>
> Thank you again for your help!
>
> Jiang
>
> 在2024年9月17日星期二 UTC+8 15:33:33<Augustin Bussy> 写道：
>
> Hi,
> everything that Frederick mentioned is very relevant. Additionally, I'd 
> like to add that the method was developed with small unit cells in mind. 
> Your cell is quite large, and this might cause memory issues, although 
> having a 2D material should help. I'll see if I am able to run it.
> Best,
> Augustin
>
> On Monday 16 September 2024 at 08:18:57 UTC+2 Frederick Stein wrote:
>
> Due to my lack of experience, I can just guess from my knowledge on RI 
> methods, the manual and what I was told by the developer. Please also 
> consider the respective manual page: 
> https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/DFT/XC/HF/RI.html#CP2K_INPUT.FORCE_EVAL.DFT.XC.HF.RI 
> .
> - Change RI_METRIC to TRUNCATED and CUTOFF_RADIUS in the &RI section to a 
> value between 1.0 and 2.0 . Lower values improve sparsity, larger values 
> increase accuracy. The shortrange Coulomb metric has a rather large range. 
> If you would like to stick to it, set the OMEGA parameter of the &RI 
> section to a value larger then 0.11 (let's say 1-10).
> - Just for testing, try a single k-point.
> - Try other values of MEMORY_CUT in &RI. Larger values (try 10) should 
> decrease the block sizes. I do not really know how it works but it does 
> have an effect on memory usage.
> - Increase EPS_FILTER in &RI to a larger value (double-check later whether 
> you have to decrease it again).
> If nothing of my suggestions work and the developer of the feature does 
> not chime in, it may be that you do not have enough memory.
> Best,
> Frederick
>
>
> Frederick Stein schrieb am Sonntag, 15. September 2024 um 18:42:31 UTC+2:
>
> Hi,
> I am not an expert with RI-HFX but I would try to run potentially cheaper 
> settings first (single k-point, smaller basis sets, larger value of omega, 
> identity metric). It may also help to have an CP2K output file or 
> supplementary input/output file if you submit jobs with a scheduler like 
> Slurm. If there is no function stack in the output file(s) given (either by 
> the compiler or by CP2K), you could also add the keywords TRACE and 
> TRACE_MASTER to your GLOBAL section.
> Best,
> Frederick
>
> yj jiang schrieb am Sonntag, 15. September 2024 um 18:13:42 UTC+2:
>
> Hi, I'm calculating band structure for C3N4 with a Ni atom (attachment). I 
> want to use HES06 + RI-HFX + ADMM. There is a "out of memory" error. How 
> can I address this? Thx. a lot.
>
> I can access a hpc with max memory of 512G.
>
>

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