pqc/external/flint-2.4.3/nmod_poly_mat/det.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2011 Fredrik Johansson
******************************************************************************/
#include "flint.h"
#include "nmod_poly.h"
#include "nmod_poly_mat.h"
void
nmod_poly_mat_det(nmod_poly_t det, const nmod_poly_mat_t A)
{
slong n = A->r;
if (n == 0)
{
nmod_poly_one(det);
}
else if (n == 1)
{
nmod_poly_set(det, nmod_poly_mat_entry(A, 0, 0));
}
else if (n == 2)
{
nmod_poly_t tmp;
nmod_poly_init(tmp, nmod_poly_mat_modulus(A));
nmod_poly_mul(det, nmod_poly_mat_entry(A, 0, 0),
nmod_poly_mat_entry(A, 1, 1));
nmod_poly_mul(tmp, nmod_poly_mat_entry(A, 0, 1),
nmod_poly_mat_entry(A, 1, 0));
nmod_poly_sub(det, det, tmp);
nmod_poly_clear(tmp);
}
else if (n < 15) /* should be entry sensitive too */
{
nmod_poly_mat_det_fflu(det, A);
}
else
{
nmod_poly_mat_det_interpolate(det, A);
}
}