[Pw_forum] How to read the output of pp.x?

[Paolo Giannozzi]

On Wed, 2014-12-17 at 10:59 -0500, Jing Wang wrote:

> I'm really confused about how can I read the local potential out 
> from the scf calculation. I used pp.x, plot_num=1 to extract the scf
> potential of the the system, however I can't really understand the
> output? 

the "output" is not meant to be read by humans but by other codes.

> Should it show the potential in cofficients of G-vectors?

no, it is in real space, in the format explained here:
http://www.quantum-espresso.org/wp-content/uploads/Doc//developer_man/developer_man.html#SECTION00080000000000000000

> Head of the output is like this:

>       25      25     100      25      25     100       2       1

FFT maximum dimensions and grids (nr1x nr2x nr3x nr1 nr2 nr3),
number of atoms, number of species

>      4        4.64900000      0.00000000      4.00000000     
>  0.00000000      0.00000000      0.00000000

ibrav, celldm(1-3) as given in scf input

>       153.2912575334        4.0000000000       70.0000000000     1

Gmax in (2pi/a)^2 units, dual (ecutrho=dual*ecutwfc), cutoff (Ry)

>    1   C     4.00
>    1       0.000000000    0.000000000    0.000000000    1
>    2       0.500000000   -0.288675135    0.000000000    1

atomic species and atomic positions. The plotted quantity in real space
(array length nr1x*nr2x*nr3) follows

Paolo

>   3.248268856E+00  3.159870688E+00  2.515974539E+00  6.186557012E-01
> -2.154636042E+00
>  -3.866568628E+00 -3.274420891E+00 -2.365272143E+00 -2.086628582E+00
> -1.945051309E+00
>  -1.918992011E+00 -1.927145835E+00 -1.943940931E+00 -1.943940931E+00
> -1.927145835E+00
>  -1.918992010E+00 -1.945051309E+00 -2.086628581E+00 -2.365272143E+00
> -3.274420890E+00
>  -3.866568627E+00 -2.154636041E+00  6.186557014E-01  2.515974539E+00
> 3.159870688E+00
>   3.159870688E+00  3.159870688E+00  2.802339131E+00  1.452305376E+00
> -1.033031298E+00
>  -3.409639826E+00 -3.654745566E+00 -2.575759384E+00 -2.021392120E+00
> -1.762140769E+00
>  -1.637123367E+00 -1.599819700E+00 -1.588050229E+00 -1.591678304E+00
> -1.588050228E+00
>  -1.599819700E+00 -1.637123366E+00 -1.762140768E+00 -2.021392119E+00
> -2.575759383E+00
>  -3.654745566E+00 -3.409639826E+00 -1.033031298E+00  1.452305376E+00
> 2.802339131E+00
>   2.515974539E+00  2.794920980E+00  2.515974539E+00  1.452305376E+00
> -6.088327143E-01
>  -2.976954364E+00 -3.787496708E+00 -2.827784418E+00 -2.048224903E+00
> -1.714196738E+00
>  -1.488710208E+00 -1.380390580E+00 -1.313398615E+00 -1.296957599E+00
> -1.296957599E+00
>  -1.313398615E+00 -1.380390580E+00 -1.488710208E+00 -1.714196738E+00
> -2.048224903E+00
>  -2.827784418E+00 -3.787496708E+00 -2.976954363E+00 -6.088327142E-01
> 1.452305376E+00
>   6.186557014E-01  1.426203806E+00  1.426203806E+00  6.186557014E-01
> -1.033031298E+00
>  -2.976954363E+00 -3.792558359E+00 -2.995197487E+00 -2.094921250E+00
> -1.698073457
> 
> 
> 
> Thanks.
> 
> 
> Jing Wang
> 
> Dept. of Physics
> 
> Georgia Tech, GA, U.S.A
> 
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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