[QE-users] [External Email] Re: difference in the order of k/q points with pw.x and ph.x
Hari Paudyal
hpaudya1 at binghamton.edu
Thu Aug 6 23:23:43 CEST 2020
Hi Pietro,
Thank you for the reply.
This system actually has an issue with the symmetry while running an EPW
calculation (which has been fixed temporarily for now in the code). I had
the phonon done with splitting a job in each q-point generated by pw.x, and
later when I ran an EPW, it crashed with error in the specific q-point
which is not in the same order with ph.x. For many of the systems I
checked, the way I run works.
I am not really worried, but trying to understand what's going on with this
specific case.
Sincerely,
Hari
On Thu, Aug 6, 2020 at 12:06 PM Pietro Delugas <pdelugas at sissa.it> wrote:
> Hi Hari
>
>
>
> They are generated by two different routines and probably with two
> different algorithms.
>
> Why are you worried about their ordering ?
>
>
>
> they are two different things.
>
>
>
> One is a MP mesh used to estimate integrals of periodic functions in the
> Brillouin Zone exploiting phase cancelations; they are used all together
> to make an SCF calculation.
>
> The other one is a uniform grid of q points at each one of which to
> compute independently a dynamical matrix using all k points (plus others)
> of the previous list. Then taken all together the dynamical matrices
> form the Fourier transform of the interatomic force constants in a 6X6X4
> supercell.
>
>
>
> Regards - Pietro
>
>
>
>
>
>
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
>
> *From: *Hari Paudyal <hpaudya1 at binghamton.edu>
> *Sent: *Thursday, August 6, 2020 4:00 PM
> *To: *Quantum Espresso users Forum <users at lists.quantum-espresso.org>
> *Subject: *[QE-users] difference in the order of k/q points with pw.x and
> ph.x
>
>
>
> Hi all,
>
>
>
> I am doing a phonon calculation of a trigonal system with SG 164. I
> noticed that the order of the k (q) points printed from pw.x and ph.x is
> different for the same k (q) grids.
>
>
>
> my inputs/outputs are as the following:
>
> *pw.x input * *ph.x input*
>
> K_POINTS {automatic} ldisp = .true.
> 6 6 4 0 0 0 nq1 = 6, nq2 = 6,
> nq3 = 4
>
>
>
> *pw.x output*
>
> number of k points= 24 Marzari-Vanderbilt smearing, width (Ry)=
> 0.0200
> cart. coord. in units 2pi/alat
> k( 1) = ( 0.0000000 0.0000000 0.0000000), wk = 0.0138889
> k( 2) = ( 0.0000000 0.0000000 0.1707981), wk = 0.0277778
> k( 3) = ( 0.0000000 0.0000000 -0.3415962), wk = 0.0138889
> k( 4) = ( 0.0000000 0.1924501 0.0000000), wk = 0.0833333
> k( 5) = ( 0.0000000 0.1924501 0.1707981), wk = 0.0833333
> k( 6) = ( 0.0000000 0.1924501 -0.3415962), wk = 0.0833333
> k( 7) = ( 0.0000000 0.3849002 0.0000000), wk = 0.0833333
> k( 8) = ( 0.0000000 0.3849002 0.1707981), wk = 0.0833333
> k( 9) = ( 0.0000000 0.3849002 -0.3415962), wk = 0.0833333
> k( 10) = ( 0.0000000 -0.5773503 0.0000000), wk = 0.0416667
> k( 11) = ( 0.0000000 -0.5773503 0.1707981), wk = 0.0833333
> k( 12) = ( 0.0000000 -0.5773503 -0.3415962), wk = 0.0416667
> k( 13) = ( 0.1666667 0.2886751 0.0000000), wk = 0.0833333
> k( 14) = ( 0.1666667 0.2886751 0.1707981), wk = 0.1666667
> k( 15) = ( 0.1666667 0.2886751 -0.3415962), wk = 0.0833333
> k( 16) = ( 0.1666667 0.4811252 0.0000000), wk = 0.1666667
> k( 17) = ( 0.1666667 0.4811252 0.1707981), wk = 0.1666667
> k( 18) = ( 0.1666667 0.4811252 -0.3415962), wk = 0.1666667
> k( 19) = ( 0.3333333 0.5773503 0.0000000), wk = 0.0277778
> k( 20) = ( 0.3333333 0.5773503 0.1707981), wk = 0.0555556
> k( 21) = ( 0.3333333 0.5773503 -0.3415962), wk = 0.0277778
> k( 22) = ( 0.0000000 0.1924501 -0.1707981), wk = 0.0833333
> k( 23) = ( 0.0000000 0.3849002 -0.1707981), wk = 0.0833333
> k( 24) = ( -0.1666667 0.4811252 -0.1707981), wk = 0.1666667
>
>
>
> *ph.x output*
>
> Dynamical matrices for ( 6, 6, 4) uniform grid of q-points
> ( 24 q-points):
> N xq(1) xq(2) xq(3)
> 1 0.000000000 0.000000000 0.000000000
> 2 0.000000000 0.000000000 0.170798095
> 3 0.000000000 0.000000000 -0.341596190
> 4 0.000000000 0.192450090 0.000000000
> 5 0.000000000 0.192450090 0.170798095
> 6 0.000000000 0.192450090 -0.341596190
> 7 0.000000000 0.192450090 -0.170798095
> 8 0.000000000 0.384900179 0.000000000
> 9 0.000000000 0.384900179 0.170798095
> 10 0.000000000 0.384900179 -0.341596190
> 11 0.000000000 0.384900179 -0.170798095
> 12 0.000000000 -0.577350269 0.000000000
> 13 0.000000000 -0.577350269 0.170798095
> 14 0.000000000 -0.577350269 -0.341596190
> 15 0.166666667 0.288675135 0.000000000
> 16 0.166666667 0.288675135 0.170798095
> 17 0.166666667 0.288675135 -0.341596190
> 18 0.166666667 0.481125224 0.000000000
> 19 0.166666667 0.481125224 0.170798095
> 20 0.166666667 0.481125224 -0.341596190
> 21 0.166666667 0.481125224 -0.170798095
> 22 0.333333333 0.577350269 0.000000000
> 23 0.333333333 0.577350269 0.170798095
> 24 0.333333333 0.577350269 -0.341596190
>
>
>
> For example, you can see the 7th point from pw.x is the 8th point from
> ph.x and so on.
>
>
>
> Any suggestions and explanations are highly appreciated.
>
>
>
> Sincerely,
>
> Hari Paudyal
>
>
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