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/*
Copyright (C) 2011 Fredrik Johansson
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 "fmpq.h"
#include "fmpq_mat.h"
int
fmpq_mat_pivot(slong * perm, fmpq_mat_t mat, slong r, slong c)
{
slong t, j;
fmpq * u;
if (!fmpq_is_zero(fmpq_mat_entry(mat, r, c)))
return 1;
for (j = r + 1; j < mat->r; j++)
{
if (!fmpq_is_zero(fmpq_mat_entry(mat, j, c)))
{
if (perm)
{
t = perm[j];
perm[j] = perm[r];
perm[r] = t;
}
u = mat->rows[j];
mat->rows[j] = mat->rows[r];
mat->rows[r] = u;
return -1;
}
}
return 0;
}