Re: [Spglib-users] spglib and cubic silicon

[Atsushi T. <atz...@gm...>]

Hi,

You have these lines:

dataset = spg_get_dataset(lattice,
                          positions,
                          types,
                          num_atom,
                              1e-5);

But they should be like this:

dataset = spg_get_dataset(lattice,
                          positions,
                          types,
                          num_atom_prim,
                              1e-5);


Togo

On Mon, Nov 10, 2014 at 11:22 PM, SAYEDE ADLANE
<say...@ho...> wrote:
> Dear spglib devlopper and users,
>
> I wanted a clarification on the use of spglib in the case of cubic silicon,
> I want to find the primitive cell of the following structure
>
> Lattice:
> 4.000000 0.000000 0.000000
> 0.000000 4.000000 0.000000
> 0.000000 0.000000 4.000000
>
> Positions :
> 0.000000 0.000000 0.000000
> 0.250000 0.750000 0.750000
> 0.000000 0.500000 0.500000
> 0.250000 0.250000 0.250000
> 0.500000 0.000000 0.500000
> 0.750000 0.750000 0.250000
> 0.500000 0.500000 0.000000
> 0.750000 0.250000 0.750000
>
> spg_find_primitive give me :
>
> Lattice:
> 2.000000 -2.000000 2.000000
> -2.000000 -0.000000 2.000000
> 0.000000 -2.000000 0.000000
>
> Positions :
> 0.000000 0.000000 0.000000
> -0.250000 -0.500000 0.250000
>
> When I use the obtained structure spg_get_dataset indicate that structure
> has  Cm (8) symmetry !!
>
> The code :
> ######################################################################################
> #include "spglib.h"
> #include <stdio.h>
>
> int main()
> {
>   double lattice[3][3] = { {4, 0, 0}, {0, 4, 0}, {0, 0, 4} };
>   double positions[32][3];
>   double pos_orig[][3] = {
>     {0, 0, 0},
>     {0.0, 0.5, 0.5},
>     {0.5, 0.5, 0.0},
>     {0.5, 0.0, 0.5},
>     {0.75, 0.25, 0.75},
>     {0.25, 0.25, 0.25},
>     {0.25, 0.75, 0.75},
>     {0.75, 0.75, 0.25}
>   };
>   int types[32];
>   int i, num_atom = 8, num_atom_prim, num_atom_bravais;
>   double symprec = 1e-5;
>
>   for (i = 0; i < num_atom; i++) {
>     positions[i][0] = pos_orig[i][0];
>     positions[i][1] = pos_orig[i][1];
>     positions[i][2] = pos_orig[i][2];
>     types[i] = 1;
>   }
>
>   num_atom_bravais = spg_refine_cell(lattice,
>                                      positions,
>                                      types,
>                                      num_atom,
>                                      symprec);
>  num_atom_prim = spg_find_primitive(lattice, positions, types,
> num_atom_bravais, symprec);
>
>   for (i = 0; i < 3; i++) {
>     printf("%f %f %f\n", lattice[i][0], lattice[i][1], lattice[i][2]);
>   }
>
> for (i = 0; i < num_atom_prim; i++) {
>     printf("%f %f %f\n",  positions[i][0], positions[i][1],
> positions[i][2]);
>   }
>
> SpglibDataset *dataset;
> const char *wl = "abcdefghijklmnopqrstuvwxyz";
> char symbol[11];
> spg_get_schoenflies(symbol, lattice, positions, types, num_atom, 1e-5);
> dataset = spg_get_dataset(lattice,
>                           positions,
>                           types,
>                           num_atom,
>                               1e-5);
>
> printf("International: %s (%d)\n", dataset->international_symbol,
> dataset->spacegroup_number );
> printf("Hall symbol:   %s\n", dataset->hall_symbol );
> printf("Number o f symmetry operations: %d\n", dataset->n_operations);
> }
> ######################################################################################
> Can someone tell me  what going wrong ?
>
> Thank you in advance ,
> Adlane
>
>
>
>
>
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>
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-- 
Atsushi Togo
http://atztogo.github.com/
atz...@gm...