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<DIV>>I think it is the too much k-points that caused the problem .when I set
the k-point to Gamma ,it iterated very quickly.but I don't know whether it is
right or wrong that I set it to Gamma.</DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I don't know either. I think you could compare
the Gamma results and 2X2X2 or 4X4X4 if necessary. If the energy different and
coordinate is nearly the same. you may could use a small K-mesh to save
computional cost. </FONT></DIV>
<DIV><FONT face=Arial size=2>As far as I tested, the energy would be within 1%
for large supercells, but the coordinates of several atoms may differ 200%. So I
have the same question like you. </FONT></DIV>
<DIV><FONT face=Arial size=2>Could anyone help us, please~ what is the benchmark
for judging whether the k-mesh is adequate? the most important thing is the
energy or the coordinates of atoms? If the energy difference is with 1% and 80%
of atoms or more in the system is nearly at the same position, but
coordinate some of atoms very different for the two case. Could we trust the
results calculated by relative small number of k points?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> <FONT face=Arial
size=2>vega</FONT></DIV>
<DIV><FONT face=Arial
size=2>=================================================================================<BR>Vega
Lew (weijia liu)<BR>PH.D Candidate in Chemical Engineering<BR>State Key
Laboratory of Materials-oriented Chemical Engineering<BR>College of Chemistry
and Chemical Engineering<BR>Nanjing University of Technology, 210009, Nanjing,
Jiangsu, China</FONT></DIV>
<DIV style="FONT: 10pt Tahoma">
<DIV><BR></DIV>
<DIV style="BACKGROUND: #f5f5f5">
<DIV style="font-color: black"><B>From:</B> <A
title="mailto:wangqj1@126.com
CTRL + 单击以下链接"
href="mailto:wangqj1@126.com">wangqj1</A> </DIV>
<DIV><B>Sent:</B> Friday, September 12, 2008 3:34 PM</DIV>
<DIV><B>To:</B> <A title="mailto:vegalew@hotmail.com
CTRL + 单击以下链接"
href="mailto:vegalew@hotmail.com">vegalew@hotmail.com</A> </DIV>
<DIV><B>Subject:</B> relax is too slow</DIV></DIV></DIV>
<DIV><BR></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> Thank you very much for your advice !</DIV>
<DIV>My input file as follows:</DIV>
<DIV>
&CONTROL<BR>
title = ZnOrelax
,<BR>
calculation = 'relax'
,<BR>
restart_mode = 'from_scratch'
,<BR>
pseudo_dir = '/root/tool/espresso-3.2.3/pseudo/'
,<BR>
prefix = ZnO
,<BR>
forc_conv_thr = 1.D-4
,<BR>
tstress = .true.
,<BR>
tprnfor = .true.
,<BR>
dt = 100
,<BR> /<BR> &SYSTEM<BR>
ibrav =
14,<BR>
celldm(1) =
18.6488,<BR>
celldm(2) =
0.666667,<BR>
celldm(3) =
1.0691,<BR>
celldm(4) =
0,<BR>
celldm(5) =
0,<BR>
celldm(6) =
-0.5,<BR>
nat =
48,<BR>
ntyp =
2,<BR>
ecutwfc = 40
,<BR>
ecutrho = 200
,<BR>
nosym = .true.
,<BR>
nbnd =
220,<BR>
occupations = 'smearing'
,<BR>
degauss = 0.002
,<BR>
smearing = 'methfessel-paxton'
,<BR>
nspin = 1
,<BR>
lda_plus_u = .false.
,<BR> /<BR> &ELECTRONS<BR>
startingpot = 'atomic'
,<BR>
startingwfc = 'atomic'
,<BR>
mixing_mode = 'plain'
,<BR>
mixing_beta = 0.7
,<BR>
diagonalization = 'cg'
,<BR> /<BR> &IONS<BR>
ion_dynamics = 'damp'
,<BR>
phase_space = 'full'
,<BR>
pot_extrapolation = 'second_order'
,<BR>
wfc_extrapolation = 'second_order'
,<BR> /<BR>ATOMIC_SPECIES<BR> Zn 65.00000
Zn.pbe-van.UPF <BR> O 16.00000
O.pbe-rrkjus.UPF <BR>ATOMIC_POSITIONS angstrom <BR>
Zn 0.000000000
1.899193710 0.000000000 1 1 1
<BR> O
0.000000000 1.899193710
2.018253260 1 1 1 <BR>
Zn 1.644750000
0.949596855 2.637550000 1 1 1
<BR> O
1.644750000 0.949596855
4.655803260 1 1 1 <BR>
Zn 3.289500000
1.899193710 0.000000000 1 1 1
<BR> O
3.289500000 1.899193710
2.018253260 1 1 1 <BR>
Zn 4.934250000
0.949596855 2.637550000 0 0 0
<BR> O
4.934250000 0.949596855
4.655803260 0 0 0<BR>
Zn 6.579000000
1.899193710 0.000000000 0 0 0
<BR> O
6.579000000 1.899193710
2.018253260 0 0 0 <BR>
Zn 8.223750000
0.949596855 2.637550000 0 0 0
<BR> O
8.223750000 0.949596855
4.655803260 0 0 0 <BR>
Zn -1.644750000
4.747984276 0.000000000 1 1 1
<BR> O -1.644750000
4.747984276 2.018253260 1 1 1
<BR> Zn 0.000000000
3.798387421 2.637550000 1 1 1
<BR> O
0.000000000 3.798387421
4.655803260 1 1 1 <BR>
Zn 1.644750000
4.747984276 0.000000000 1 1 1
<BR> O
1.644750000 4.747984276
2.018253260 1 1 1 <BR>
Zn 3.289500000
3.798387421 2.637550000 0 0 0
<BR> O
3.289500000 3.798387421
4.655803260 0 0 0 <BR>
Zn 4.934250000
4.747984276 0.000000000 0 0 0
<BR> O
4.934250000 4.747984276
2.018253260 0 0 0 <BR>
Zn 6.579000000
3.798387421 2.637550000 0 0 0
<BR> O
6.579000000 3.798387421
4.655803260 0 0 0 <BR>
Zn 0.000000000
1.899193710 5.275100000 1 1 1
<BR> O
0.000000000 1.899193710
7.293353260 1 1 1 <BR>
Zn 1.644750000
0.949596855 7.912650000 1 1 1
<BR> O
1.644750000 0.949596855
9.930903260 1 1 1 <BR>
Zn 3.289500000
1.899193710 5.275100000 1 1 1
<BR> O
3.289500000 1.899193710
7.293353260 1 1 1 <BR>
Zn 4.934250000
0.949596855 7.912650000 0 0 0
<BR> O
4.934250000 0.949596855
9.930903260 0 0 0 <BR>
Zn 6.579000000
1.899193710 5.275100000 0 0 0
<BR> O
6.579000000 1.899193710
7.293353260 0 0 0 <BR>
Zn 8.223750000
0.949596855 7.912650000 0 0 0
<BR> O
8.223750000 0.949596855
9.930903260 0 0 0 <BR>
Zn -1.644750000
4.747984276 5.275100000 1 1 1
<BR> O -1.644750000
4.747984276 7.293353260 1 1 1
<BR> Zn 0.000000000
3.798387421 7.912650000 1 1 1
<BR> O
0.000000000 3.798387421
9.930903260 1 1 1 <BR>
Zn 1.644750000
4.747984276 5.275100000 1 1 1
<BR> O
1.644750000 4.747984276
7.293353260 1 1 1 <BR>
Zn 3.289500000
3.798387421 7.912650000 0 0 0
<BR> O
3.289500000 3.798387421
9.930903260 0 0 0 <BR>
Zn 4.934250000
4.747984276 5.275100000 0 0 0
<BR> O
4.934250000 4.747984276
7.293353260 0 0 0 <BR>
Zn 6.579000000
3.798387421 7.912650000 0 0 0
<BR> O
6.579000000 3.798387421
9.930903260 0 0 0 <BR>K_POINTS automatic
<BR> 4 4 4 0 0 0 </DIV>
<DIV> </DIV>
<DIV>According your advice I found the CPU user% ratio is about 98% and the swap
is about 16%.I think it is the too much k-points that caused the problem .when I
set the k-point to Gamma ,it iterated very quickly.but I don't know whether it
is right or wrong that I set it to Gamma.</DIV>
<DIV> </DIV>
<DIV>Sincerely</DIV>
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