I took a simple 32-atom supercell of aluminum. Here is the input:
control
calculation='scf'
restart_mode='from_scratch',
pseudo_dir = '.'
outdir=./tmp/,
prefix='al'
tprnfor = .true.
tstress = .true.
disk_io='none'
/
&system
ibrav= 0, A=4.05, nat= 32, ntyp= 1, ecutwfc =60.0,
occupations='smearing', smearing='marzari-vanderbilt', degauss=0.05
/
&electrons
diagonalization='david'
mixing_beta = 0.7
/
CELL_PARAMETERS alat2 0 00 2 00 0 2
ATOMIC_SPECIES
Al 26.98 Al.pbe-n-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS crystal
Al 0.00000000 0.00000000 0.00000000
Al 0.25000000 0.25000000 0.00000000
Al 0.25000000 0.00000000 0.25000000
Al 0.00000000 0.25000000 0.25000000
Al 0.50000000 0.00000000 0.00000000
Al 0.75000000 0.25000000 0.00000000
Al 0.75000000 0.00000000 0.25000000
Al 0.50000000 0.25000000 0.25000000
Al 0.00000000 0.50000000 0.00000000
Al 0.25000000 0.75000000 0.00000000
Al 0.25000000 0.50000000 0.25000000
Al 0.00000000 0.75000000 0.25000000
Al 0.50000000 0.50000000 0.00000000
Al 0.75000000 0.75000000 0.00000000
Al 0.75000000 0.50000000 0.25000000
Al 0.50000000 0.75000000 0.25000000
Al 0.00000000 0.00000000 0.50000000
Al 0.25000000 0.25000000 0.50000000
Al 0.25000000 0.00000000 0.75000000
Al 0.00000000 0.25000000 0.75000000
Al 0.50000000 0.00000000 0.50000000
Al 0.75000000 0.25000000 0.50000000
Al 0.75000000 0.00000000 0.75000000
Al 0.50000000 0.25000000 0.75000000
Al 0.00000000 0.50000000 0.50000000
Al 0.25000000 0.75000000 0.50000000
Al 0.25000000 0.50000000 0.75000000
Al 0.00000000 0.75000000 0.75000000
Al 0.50000000 0.50000000 0.50000000
Al 0.75000000 0.75000000 0.50000000
Al 0.75000000 0.50000000 0.75000000
Al 0.50000000 0.75000000 0.75000000
K_POINTS automatic11 11 11 0 0 0
Here, I am running on single node with 48 processor with different number
of nkand nb
For example :
mpiexec.hydra -np 48 /USERS/pranav/compilation/q-e-qe-6.8/bin/pw.x -in
al.scf.david.in -nk 3 -nb 4
In First study, I varied nk while fixed nb=1. Here is the result
*nk nb time(sec)* 1 1 2062 1 1633 1 1444 1 1386 1 1388 1 13112 1 141
In second run, I fixed nk at 3 and varied nb and Here is the result
*nk nb time(sec)* 3 1 1443 2 1813 4 2553 8 426
Why is run-time increasing with increase in nb in second run? I was hoping
for decreasing in trend.
*Note: QE v6. 8 is compiled with intel-oneapi and internal FFT library*
--
PRANAV KUMAR
Research Scholar
IIT MADRAS (AM18D011)
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