[Pw_forum] Crash in routine set_sym_bl
Sergi Vela
sergi.vela at gmail.com
Fri Feb 13 16:38:50 CET 2015
Dear Paolo,
Do you mean: "a*sqrt(3)/2" instead of "2a/sqrt(3)", right?
Otherwise I'm lost... I would understand small numeric deviations from the
totally simmetric axes, but "2a/sqrt(3)" means that the correct axes would
be those ones:
0.852441 0.000000 0.000000 -0.426221 *0.984314* 0.000000 0.000000
0.000000 1.000000
which are quite far away from mines:
0.852441 0.000000 0.000000 -0.426221 *0.738236* 0.000000 0.000000
0.000001 1.000000
I always calculate the axes this way (triclinic cell's vectors), using my
own fortran code (this is probably the error, do I need to fix the number
of decimals that appearm right?):
v1 = (a, 0, 0),
v2 = (b*cos(gamma), b*sin(gamma), 0)
v3 = (c*cos(beta), c*(cos(alpha)-cos(beta)cos(gamma))/sin(gamma),
c*sqrt( 1 + 2*cos(alpha)cos(beta)cos(gamma)-
cos(alpha)^2-cos(beta)^2-cos(gamma)^2 )/sin(gamma)
And those are the unit cell paramers (extracted from the .cif file that I
attach):
_cell_length_a 23.0703
_cell_length_b 23.0703
_cell_length_c 27.0638
_cell_angle_alpha 90.0000
_cell_angle_beta 90.0000
_cell_angle_gamma 120.0000
Thanks! For your help and specially for creating this code, I've been
working with it quite some time and I'm very satisfied overall.
Sergi
2015-02-13 14:38 GMT+01:00 Paolo Giannozzi <paolo.giannozzi at uniud.it>:
> On Fri, 2015-02-13 at 11:23 +0100, Sergi Vela wrote:
>
> > "Error in routine set_sym_bl (1): Symmetry group not a group!
>
> this is the error
>
> > Use standard orientations for axis"
>
> and this is a hint. One known case in which this happens is for
> hexagonal lattices with a basal crystal axis rotated of 15 degrees
> wrt to the cartesian axis.
> In your case, it happens (I think) because you choose these axis:
>
> CELL_PARAMETERS
> 0.85244126841036916 0.0000000000000000 0.000000
> -0.42622032521263958 0.73823597207445180 0.000000
> 3.13916478650538062E-007 5.43719027573123104E-007 1.000000
>
> that are very close but not exactly equal to what you wanted:
> a 0 0
> -a/2 2a/sqrt(3)
> 0 0 c
> so some symmetry operations that should be there, aren't found
>
> > One piece of information: I am running it with QE v.5.1.1. When I run
> > it using version 4.2.1 I don't get any error.
>
> because v.4.2.1 didn't check if the group is a group. It is not needed
> in most cases, but for some calculations it is
>
> Paolo
>
> > Any help is appreciated. Thanks!
> >
> >
> > Sergi Vela,
> > University of Strasbourg
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20150213/8304e862/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: SURF-EXP3.cif
Type: application/octet-stream
Size: 22311 bytes
Desc: not available
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20150213/8304e862/attachment.obj>
More information about the users
mailing list