[Wien] Speeding up calculations in parallel mose

[Laurence Marks]

Beyond what Pavel said, you are still talking weeks for a calculation. A
critical issue is whether you are using sensible parameters. Many people
have used RKMAX 7 and 1000 kpts assuming that those are "right" -- they are
not. If your H and He have small RMTs then RKMAX should also be smaller.
Also, what is needed is a k-point density, so the number of k-points is
less for a supercell.

I suggest that you copy your case.struct file to a new directory then do
init_lapw in that directory. 23.2 will pick appropriate values for you, and
you can then copy them over.

Beyond that, get your boss to buy you a faster computer.

--
Professor Laurence Marks (Laurie)
Walter P Murphy Professor Emeritus
Department of Materials Science and Engineering, Northwestern University
www.numis.northwestern.edu
"Research is to see what everybody else has seen, and to think what nobody
else has thought" Albert Szent-Györgyi

On Tue, Aug 22, 2023, 04:32 Victor Zenou <zanov at post.bgu.ac.il> wrote:

> Dear Wien2k users!
>
> I’m investigating  a 54 tungsten atoms  supercell ,  with 1 helium atom and 1 hydrogen atom (primitive cell) at different interstitial sites.  It takes ~ 46 hr per  calculation cycle, and half of it (~23 hr) in parallel mode.  The Wien2k version 23.2 was installed on Ubuntu 22.04.2 LTS. using gfortran and I set OMP_NUM_THREADS to  1, and used 2 parallel_jobs in the current work. The computer is build from  i7-10700 processor @ 2.90GHz (8 cores; 16 Threads), 32 GB memory and 500 GB SSD. In the past using the same computer , it took me ~ 14 hr per cycle for the same calculations, meaning 2-4 times faster than today. The wien2k version was 21.1, bur I can’t remember if the calculations were done in parallel, probably yes (I think  the number of parallel jobs was chosen automatically), and I think I set   OMP_NUM_THREADS to  4, but again I’m not sure.How can I speed up my calculations using the same computer?Best regards, Victor
>
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