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<p>Is the memory usage that you showed for the 3*3*1 or 4*4*1 supercell? Try to figure out if there is no memory problem for the 4*4*1. If you can run a MPI calculation, then do it using more than one node.<br>
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<p>When you generate (with "run_kgenhf_lapw -redklist") a reduced k-mesh for a -redklist calculation, the reduced k-mesh is in case.klist_rfbz, but not in case.klist_ibz and case.klist_fbz which are still for the original k-mesh.<br>
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<p>If you are interested only in the electronic structure (DOS), then I strongly recommend the use of the option "-diagfh" (see explanations in the user's guide) for a huge speed up of the calculation (supposing that this approximation is accurate enough in
your case).<br>
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<p>Using -ec 0.6 is nonsense.<br>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> Wien <wien-bounces@zeus.theochem.tuwien.ac.at> on behalf of Yifan Ding <yfding0375@foxmail.com><br>
<b>Sent:</b> Saturday, May 15, 2021 10:25 AM<br>
<b>To:</b> wien<br>
<b>Subject:</b> [Wien] How to select the appropriate nband in hybrid functionals calculations</font>
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<div>Dear Prof. Tran and Prof. Abo,</div>
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<div>Thank you very much for your kindly reply.</div>
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<div>The 4*4*1 supercell (including 64 atoms) I want to calculate is really large. When I set the h-BN monolayer 3*3*1 supercell including 36 atoms, the calculation can be successfully completed.</div>
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<div>At present, I am doing a calculation of 3*3*1 supercell, and the SCF is running HF in parallel mode. I ssh to the computing node and use the command 'top' to query the following information:</div>
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<div><i> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND</i></div>
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<div><i>15914 yurc 20 0 2681m 2.6g 916 R 100.0 4.1 953:27.35 hfc </i></div>
<div><i> 350 root 39 19 0 0 0 R 99.9 0.0 5128682h kipmi0 </i></div>
<div><i>15789 yurc 20 0 2682m 2.6g 824 R 99.9 4.1 953:27.78 hfc </i></div>
<div><i>15820 yurc 20 0 2682m 2.6g 916 R 99.9 4.1 953:27.85 hfc </i></div>
<div><i>15882 yurc 20 0 2681m 2.6g 916 R 99.9 4.1 953:27.38 hfc </i></div>
<div><i>15851 yurc 20 0 2682m 2.6g 904 R 99.6 4.1 953:27.47 hfc </i> </div>
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<div>The above five "yurc" are my user names, and it seems that there is no problem with memory usage. I didn't use MPI parallel calculations in 3*3*1 supercell or 4*4*1 supercell calculations, and all calculations are k-point parallel. For the 3*3*1 supercell,
the total number of k points is 9, and there are 5 k points in the case.klist_ibz file.</div>
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<div>Back to the 4*4*1 supercell calculations with "Error in Parallel HF", although I set nx = 1, ny = 1, nz = 1 for the reduced k-mesh, because the total k points are 10, the number of k points displayed by case.klist_ibz is 5. In 4*4*1 supercell calculations
with "Error in Parallel HF", the number of nodes is 1 and the number of cores is 5. Setting -ec 0.6 is indeed very rough, because the value of nband will affect the energy range of DOS, but choosing a large nband will make the hybrid functional calculation
very slow. I want to quickly calculate and judge the upper limit of the energy window of DOS by setting different nband, and finally choose the appropriate nband to get DOS of -20 eV ~ 20 eV. In order to complete SCF faster, I used -redklist. Therefore, I
set "run_lapw -hf -redklist -ec 0.6 -p -i 999 > output.log" in 4*4*1 supercell calculations. </div>
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<div>I am very grateful to the two professors for your enthusiastic help and help me find the questions and answers I didn't found in the mailing list. </div>
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<div>I found out from the installation folder that the version information of Wien2k I used is WIEN2k_14.2 (Release 15/10/2014). Because I use the public supercomputer of the Institute of Physics, I found on the network that using the command "grep hf /var/log/syslog"
seems to require root, and I don't have permission. At present, many people are using the WIEN2k_14.2 in our institute. If there is a chance later, I will try to upgrade it.</div>
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