[Pw_forum] k-point grids...and all that

[Paolo Giannozzi]

On Sep 15, 2008, at 5:30 , Paul M. Grant wrote:
> The ability to compute weighted 1st BZ grids according to the  
> Monkhorst-Pack scheme is included somewhere within espresso-4.0,  
> but exactly where is unclear (k-points.f90?  No).
>
of course no, since it is non-existent:
$ ls -l */k-points.f90
ls: */k-points.f90: No such file or directory
There is however an auxiliary code, pwtools/kpoints.f, that produces  
Monkhorst-Pack
grids with weights (executable: kpoints.x).

Inside q-e, there are several routines for the generation of  
automatic k-point grids.
See PW/setup.f90, under
   !
   ! ... Automatic generation of k-points (if required)
   !
Routines kpoint_grid_efield and kp_strings are specific for  
macroscopic field
and Berry phase calculations; kpoint_grid and setupkpoint (undocumented)
take care of the typical scf case. The difference between the two is  
just
aesthetic.
> Finally, is there a visualization tool to display the k-point  
> distribution within the  1st BZ?  XcrysDen?
>
for sure: see http://www.xcrysden.org/img/xcrysden-in-action.png,  
first picture

Paolo
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Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222