[Pw_forum] Error in routine sym_rho_init_shell (4): lone vector

[Paolo Giannozzi]

On Sun, Dec 3, 2017 at 2:09 PM, Manoar Hossain <manoarphy at niser.ac.in>
wrote:

Thanks for your kind reply but [...] Your first suggestion (A) is not
> working, can you please enlighten me why ?
>

I am not a Zen master. I can just explain the origin of a problem, but if
you do not read, or do not understand, my explanations, there is nothing I
can do. Anyway:
1. I am 10% sure my fix works for the input data you sent a few days ago
2. The input data you just sent has the same problem: input lattice vectors
that are close to hexagonal, but not exactly hexagonal


> Also what is the permanent solution ?
>

The permanent solution is to disable symmetry with user-supplied lattice
vectors.

Here I attached the relevant files.
>
> Thanks in advance.
>
>
>
>
> Regards,
>
> On Fri, Dec 1, 2017 at 10:03 PM, Paolo Giannozzi <p.giannozzi at gmail.com>
> wrote:
>
>> On Thu, Nov 30, 2017 at 3:02 PM, Manoar Hossain <manoarphy at niser.ac.in>
>> wrote:
>>
>> can anybody please tell me why this is happening ?
>>>
>>
>> the code recognizes hexagonal symmetry in your data. In order to
>> symmetrize the charge density, the code needs to reorganize G-vectors in
>> such a way that only entire shells of G-vectors are present on each
>> processor. Since however your lattice vectors are not exactly hexagonal,
>> the algorithm may fail in some unfortunate cases, ending up with half a
>> shell on one processor, half a shell on another one. Unfortunately there is
>> no easy workaround, but ...
>>
>> And without reducing (or changing) the lattice parameter then how one can
>>> get rid of this error ?
>>>
>>
>> ... if you specify your lattice vectors as
>>
>> CELL_PARAMETERS
>>    7.1189946603   12.330460450   0.000000000
>>   -7.1189946603   12.330460450   0.000000000
>>   0.0000000       0.0000000    19.000000000
>>
>> (12.330460450=7.1189946603*sqrt(3)) instead of
>>
>> CELL_PARAMETERS
>>    7.1189946603   12.330463153   0.000000000
>>   -7.1189946603   12.330463153   0.000000000
>>    0.0000000       0.0000000    19.000000000
>>
>> it works. As a rule, it is a good idea to use "exact" lattice vectors (by
>> specifying ibrav, or the space group) instead of user-supplied lattice
>> vectors whenever symmetry is important.
>>
>> Paolo
>> --
>> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>> Phone +39-0432-558216 <+39%200432%20558216>, fax +39-0432-558222
>> <+39%200432%20558222>
>>
>>
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>
>
>
> --
> Manoar Hossain
> Research Scholar
> School of Physical Sciences
> NISER, Bhubaneswar
>
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>



-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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