[Wien] lapw1 vs lapwso speed

[pluto]

Dear All,

Thank you for the answers.

Just to clarify, this questions was regarding a large case.klist_band 
file. For the scf run, I always use much smaller case.klist, especially 
for a large slab that has no out-of-plane dispersion.

Best,
Lukasz





On 2023-06-11 21:47, Peter Blaha wrote:
> This is usually not true, except when EMAX is set to 100 Ry or so.
> 
> We use for lapwso  as basisset the lapw1 eigenstates, thus the
> dimension of the lapwso eigenvalue problem is only  2 * NE, where NE
> is typically (depending on EMAX) 20-30% of NMAT of lapw1.
> 
> Am 11.06.2023 um 16:33 schrieb Yundi Quan via Wien:
>> The matrix that lapw1 -up solves is the spin up part of the 
>> Hamiltonian and it should be much smaller than the matrix that lapwso 
>> solves.
>> 
>> On Sunday, June 11, 2023, Peter Blaha <peter.blaha at tuwien.ac.at 
>> <mailto:peter.blaha at tuwien.ac.at>> wrote:
>> 
>>     The speed of lapwso depends on EMAX in case.in1, which limits the
>>     number of eigenvalues calculated in lapw1 and used as basis for 
>> lapwso.
>> 
>>     With EMAX=5.0 the speed of lapw1 and lapwso is usually similar.
>>     With larger emax lapwso may take much more time.
>> 
>>     Am 11.06.2023 um 12:36 schrieb pluto via Wien:
>> 
>>         Dear All,
>> 
>>         When calculating bands for a large slab I have following 
>> sequence:
>> 
>>         Sun May 14 12:33:03 PM CEST 2023> (x) lapw1 -band -up -p
>>         Sun May 14 02:25:26 PM CEST 2023> (x) lapw1 -band -dn -p
>>         Sun May 14 04:17:22 PM CEST 2023> (x) lapwso -up -p
>>         Mon May 15 01:30:05 AM CEST 2023> (x) qtl -up -p -band -so
>>         Mon May 15 01:30:05 AM CEST 2023> (x) lapw2 -p -fermi -so -up
>>         Mon May 15 01:51:51 AM CEST 2023> (x) qtl -dn -p -band -so
>>         Mon May 15 01:51:51 AM CEST 2023> (x) lapw2 -p -fermi -so -dn
>> 
>>         As you can see lapwso takes much longer than lapw1 (approx. 9h
>>         vs 2h). Is this normal for band calculations?
>> 
>>         I have 128 GB of RAM in this computer, so this is not a RAM
>>         issue. Here is what top shows for the lapwso calculation (I 
>> have
>>         4 parallel localhost processes in .machines, OMP=2 and no 
>> mpi):
>> 
>>         Tasks: 505 total,   2 running, 503 sleeping,   0 stopped,   0 
>> zombie
>>         %Cpu(s): 24.0 us,  0.2 sy,  0.0 ni, 75.7 id,  0.0 wa,  0.1 hi, 
>>         0.0 si, 0.0 st
>>         MiB Mem : 128047.1 total,   1845.8 free,  16809.0 used, 
>> 111158.6
>>         buff/cache
>>         MiB Swap:  32088.0 total,  31471.5 free,    616.5 used. 
>> 111238.1
>>         avail Mem
>> 
>>               PID USER      PR  NI    VIRT    RES    SHR S  %CPU       
>>   %MEM     TIME+ COMMAND
>>         1336417 lplucin   20   0 6417856   4.8g  15840 R 199.3   3.8   
>>        1294:13 lapwso
>>         1336392 lplucin   20   0 2848204   2.3g  15880 S 146.8   1.9   
>>        1295:30 lapwso
>>         1336391 lplucin   20   0 2848188   2.4g  15916 S 130.6   1.9   
>>        1304:23 lapwso
>>         1336396 lplucin   20   0 2848060   2.3g  15816 S  99.7   1.9   
>>        1288:06 lapwso
>> 
>>         .machines file:
>> 
>>         omp_global:8
>>         omp_lapw1:2
>>         omp_lapw2:2
>>         omp_lapwso:2
>>         1:localhost
>>         1:localhost
>>         1:localhost
>>         1:localhost
>>         granularity:1
>> 
>>         Best,
>>         Lukasz
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>> 
>>     --     
>> --------------------------------------------------------------------------
>>     Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
>>     Phone: +43-1-58801-165300
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