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/*
Copyright (C) 2015 Tommy Hofmann
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "fmpz_mat.h"
slong
fmpz_mat_howell_form_mod(fmpz_mat_t A, const fmpz_t mod)
{
slong i, j, n;
slong k;
if (fmpz_mat_is_empty(A))
return 0;
n = A->r;
k = n;
fmpz_mat_strong_echelon_form_mod(A, mod);
for (i = 0; i < n; i++)
{
if (fmpz_mat_is_zero_row(A, i))
{
k--;
for (j = i + 1; j < n; j++)
{
if (!fmpz_mat_is_zero_row(A, j))
{
fmpz_mat_swap_rows(A, NULL, i, j);
j = n;
k++;
}
}
}
}
return k;
}