[Pw_forum] error cannot remap grid on k-point list

[Paolo Giannozzi]

On Sep 15, 2008, at 15:51 , Elena Roxana Margine wrote:

> I have been trying to perform an electron-phonon calculation for a  
> hexagonal
> structure but the calculation crashes at second point on a 2x2x2 q- 
> mesh in
> the elphon subroutine with the error "cannot remap grid on k-point  
> list"
> [...]
> The problem is that the code finds more irreducible k-points than  
> there should
> be. In this example k(27) is the same as k(25) and k(29) is the  
> same as k(9).
> So, the correct number of k points should be 26 not 30.

it is a known[*] problem of all recent versions of the phonon code,  
fixed in the
CVS version (which is undergoing some heavy restructuring of the  
symmetry
part).  Fixing it in the stable version requires some nontrivial  
changes. As a
workaround, try to run the intermediate non-scf calculation with the   
'phonon'
keyword instead of the "ldisp" option: you should get the correct  
number of
k-points. Thank you for bringing this to our attention and for  
providing a simple
and useful bug report

Paolo

[*] that is, known to me and to a couple of other guys
---
Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222