[Pw_forum] neb.x with v5.0.2

[Paolo Giannozzi]

The only change between v.5.0.1 and 5.0.2 that might explain 
what you see is the following one:
http://qe-forge.org/gf/project/q-e/scmsvn/?action=browse&path=%
2F&view=rev&revision=9356
In fact the paths for the two versions are not the same,
although they are not very different:

<      initial path length           = 10.6709 bohr
<      initial inter-image distance  =  0.9701 bohr
---
>      initial path length           =  9.8891 bohr
>      initial inter-image distance  =  0.8990 bohr

Apparently this patch works in some cases but not all.
While waiting for better ideas, you may remove the 
IF ( idx > 1 ) THEN ... END IF section in 
NEB/src/engine_to_path_pos.f90 and recompile. 
Thank you for reporting this problem.

P.

On Mon, 2013-06-03 at 23:14 +0200, paolo paoli100 wrote:
> Yes, they are equivalent by a lattice translation but intermediate
> images are not equivalent, because they are set between the first
> image and a last image, different from the one I selected. I get
> “strange” structures of the intermediate images. I still have 2 CO
> molecules, but one is in my supercell, and the other is splitted, the
> C atom is in the supercell I built and the O atom is in the next one.
> 
>  I also tried to run the same input file with version 5.0.1 and QE
> 5.0.1 kept all the atomic positions I listed in my input file. 
> 
> Thanks a lot,
> 
> Luca Dietz
> 
> Bachelor of Science in Chemical Engineering
> 
> Politecnico di Milano, Italy
> 
> 
> 
> 2013/6/1 Paolo Giannozzi <paolo.giannozzi at uniud.it>
>         On Sat, 2013-06-01 at 17:18 +0200, paolo paoli100 wrote:
>         
>         > I set atomic positions of the first and last image, but
>         after running
>         > the first iteration, the file.crd has showed atomic
>         positions
>         > different from the ones I choose. In the last image, a “-“
>         appeared
>         
>         > before the “x” coordinate of an oxygen. [...]
>         > How can I deal with this problem?
>         
>         
>         are you sure it is a problem? are the two positions, the
>         original
>         and the modified one, really different, i.e. not equivalent by
>         a
>         lattice translation?
>         
>         P.
>         --
>         Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
>         Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>         Phone +39-0432-558216, fax +39-0432-558222
>         
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-- 
 Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
 Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
 Phone +39-0432-558216, fax +39-0432-558222