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GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it

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#include "typedef.h"

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#include "matrix.h"

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#include "orbit.h"

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#include "symm.h"

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#include "tools.h"

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/**************************************************************************\

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@---------------------------------------------------------------------------

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@---------------------------------------------------------------------------

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@ FILE:  vor_vertices.c

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@---------------------------------------------------------------------------

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@---------------------------------------------------------------------------

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@

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\**************************************************************************/

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/**************************************************************************\

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@---------------------------------------------------------------------------

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@ matrix_TYP **voronoi_vertices(form, grp, anz, form_min, SV_no)

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@ matrix_TYP *form;

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@ bravais_TYP *grp;

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@ int *anz, *form_min, *SV_no;

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@

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@ calculates the voronoi_vertices, i.e. the matrices in the space of

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@ symmetric matrices, that are invariant under the action of G^{tr},

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@ where the voronoi vertices are defined by the sum over all g in the

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@ group 'grp'  of

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@      g x^{tr}x g,

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@ where x is a shortest vector of 'form'.

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@

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@ The number of these vertices is returned via (int *anz)

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@ the number of shortest vectors of 'form' via (int *SV_no) and

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@ the minimum of 'form' via (int *form_min)

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@---------------------------------------------------------------------------

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@

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\**************************************************************************/

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matrix_TYP **voronoi_vertices(form, grp, anz, form_min, SV_no)

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matrix_TYP *form;

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bravais_TYP *grp;

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int *anz, *form_min, *SV_no;

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{

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    int min_norm, orbit_anz;

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    int *subdiv, *svi;

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    matrix_TYP *SV, **vf;

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    int i,j,k,l, n;

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    n = form->cols;

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    SV = shortest(form, &min_norm);

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    *SV_no = SV->rows;

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    *form_min = min_norm;

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    subdiv = orbit_subdivision(SV, grp, &orbit_anz);

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    if((vf = (matrix_TYP **)malloc(orbit_anz *sizeof(matrix_TYP *))) == NULL)

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    {

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       printf("malloc failed\n");

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       exit(2);

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    }

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    for(i=0;i<orbit_anz;i++)

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    {

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      vf[i] = init_mat(n, n, "");

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      vf[i]->flags.Symmetric = TRUE;

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    }

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    for(i=0;i<SV->rows;i++)

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    {

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      svi = SV->array.SZ[i];

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      j = subdiv[i]-1;

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      for(k=0;k<n;k++)

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        for(l=0;l<=k;l++)

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        {

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           vf[j]->array.SZ[k][l] += (svi[k] * svi[l]);

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           if(k!= l)

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             vf[j]->array.SZ[l][k] = vf[j]->array.SZ[k][l];

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        }

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    }

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    for(i=0;i<orbit_anz;i++)

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    {

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      l = 0;

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      for(j=0;j<n && l != 1;j++)

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         for(k=0;k<=j && l != 1 ;k++)

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         {

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           if(vf[i]->array.SZ[j][k] != 0)

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           {

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             if(l == 0)

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               l = vf[i]->array.SZ[j][k];

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             else

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               l = GGT(l, vf[i]->array.SZ[j][k]);

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             if(l<0)

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              l = -l;

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           }

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         }

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       if(l != 1)

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       {

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         for(j=0;j<n;j++)

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          for(k=0;k<=j;k++)

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          {

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            vf[i]->array.SZ[j][k] /= l;

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            vf[i]->array.SZ[k][j] = vf[i]->array.SZ[j][k];

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          }

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       }

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    }

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    free(subdiv);

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    free_mat(SV);

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    *anz = orbit_anz;

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    return(vf);

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}

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