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

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/****************************************************************************
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**
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*A  find_image.c                ANUPQ source                   Eamonn O'Brien
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**
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*Y  Copyright 1995-2001,  Lehrstuhl D fuer Mathematik,  RWTH Aachen,  Germany
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*Y  Copyright 1995-2001,  School of Mathematical Sciences, ANU,     Australia
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**
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*/
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#include "pq_defs.h"
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#include "pcp_vars.h"
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#include "pga_vars.h"
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#include "pq_functions.h"
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/* find the image of the allowable subgroup having supplied label under
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   the action of automorphism; compute and return its label */
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int
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find_image(int label, int **auts, struct pga_vars *pga, struct pcp_vars *pcp)
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{
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   int index;
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   int **A;
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   int **Image, **Image_transpose;
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   int **S, **S_transpose;
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   int *subset;
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   int K;
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   subset = allocate_vector(pga->s, 0, 0);
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   A = allocate_matrix(pga->q, pga->q, 0, FALSE);
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   assemble_matrix(A, pga->q, auts, pcp);
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   S = label_to_subgroup(&index, &subset, label, pga);
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   S_transpose = transpose(S, pga->s, pga->q);
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   Image_transpose =
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       multiply_matrix(A, pga->q, pga->q, S_transpose, pga->s, pga->p);
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   Image = transpose(Image_transpose, pga->q, pga->s);
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   K = echelonise_matrix(Image, pga->s, pga->q, pga->p, subset, pga);
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   free_matrix(A, pga->q, 0);
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   free_matrix(S, pga->s, 0);
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   free_matrix(S_transpose, pga->q, 0);
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   free_matrix(Image_transpose, pga->q, 0);
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   label = subgroup_to_label(Image, K, subset, pga);
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   free_matrix(Image, pga->s, 0);
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   free_vector(subset, 0);
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   return label;
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}
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