Hello, Sure. I've shared the input and output in the following link: https://drive.google.com/drive/folders/1trdcWUw7GKSw0zLQouxygpaKwOl7_2KM?usp=sharing
Kind regards, On Sat, Dec 12, 2020 at 5:01 PM Lorenzo Paulatto <[email protected]> wrote: > > Aslo I have tried running the band calculation on different systems (local > pc with 12 nodes) and HPC (with 36 and 72 nodes). Every time I have the > same problem. I have tried QE 6.5 and 6.4 for this calculation all with > same issue. > > > For comparison, I have here a calculation with 119 electrons, 10 k-points, > 100 Ry kinetic energy cutoff. One SCF iteration takes about 5 seconds on 32 > CPUs (2 nodes of a very old computing cluster that has since been retired). > From 120 to 190 electrons there should be around a factor 4 of CPU times. > But it would be easier to say which is the source of the discrepancy if you > sent your input and output files to teh list, to have a look > > > cheers > > > > All the best, > Zahra > > > > > On Fri, Dec 11, 2020, 22:22 Lorenzo Paulatto <[email protected]> wrote: > >> Hello Zahra, >> >> if I understand correctly, you manage to do the scf calculation, but then >> the band calculation is very slow. The cost per k-point of nscf should be >> more or less the same as the cost per k-point of one scf iteration. If it >> is not, there is something wrong. One possible problem, is that ecutwfc is >> interpreted differently during nscf. A tight value (1.d-12 or less) may >> cause the threshold of diagonalization in nscf to become too small and very >> slow to converge. This should be fixed in v 6.7, but you can just increase >> ecutwfc in nscf if you're using a previous version. >> >> If not, it may be a problem with parallelism, i.e. running on too many >> CPUs or some proper human error like running with all the processes on the >> same computing node. >> >> >> cheers >> On 2020-12-11 19:25, Zahra Khatibi wrote: >> >> Dear all, >> >> First of all, I hope everyone is safe and well in these crazy times. >> I'm calculating the electronic band dispersion of a 2D heterostructure >> with a 59 atom unit cell. This system is a small bandgap (10-20 meV) >> semiconductor. The number of valence bands is (valence electrons/2) 181. >> When I set 'nbnd' to 190, the band structure calculation costs me 30 >> minutes for each k point on HPC with 72 processors. This means that if I do >> a simple band calculation for a high symmetry path with 100 points within, >> I have to wait almost 50 hours! This even becomes worst when I try to >> evaluate the band dispersion with SOC switched on (twice the spin >> degenerate band calculation). >> Since the band dispersion evaluation is the major part of our study, I >> was wondering if there is a way around this problem, like reducing the >> number of bands by only looking at energy interval close to Fermi energy? >> I could see that there are lots of papers and studies in the literature >> with huge unit cells and heavy atoms that have presented numerous band >> structures (using QE). So I really appreciate it if you could help me here. >> >> Kind regards, >> -- >> Z. Khatibi >> School of Physics >> Trinity College Dublin >> >> _______________________________________________ >> Quantum ESPRESSO is supported by MaX (www.max-centre.eu) >> users mailing list >> [email protected]https://lists.quantum-espresso.org/mailman/listinfo/users >> >> _______________________________________________ >> Quantum ESPRESSO is supported by MaX (www.max-centre.eu) >> users mailing list [email protected] >> https://lists.quantum-espresso.org/mailman/listinfo/users > > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list > [email protected]https://lists.quantum-espresso.org/mailman/listinfo/users > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
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