pqc/external/flint-2.4.3/fmpz_poly_mat/prod.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 <stdlib.h>
#include "flint.h"
#include "fmpz_poly.h"
#include "fmpz_poly_mat.h"
static void
binary_splitting(fmpz_poly_mat_t P, fmpz_poly_mat_t * const factors,
slong n1, slong n2)
{
if (n2 - n1 <= 0)
{
fmpz_poly_mat_one(P);
}
else if (n2 - n1 == 1)
{
fmpz_poly_mat_set(P, factors[n1]);
}
else if (n2 - n1 == 2)
{
fmpz_poly_mat_mul(P, factors[n1], factors[n1 + 1]);
}
else
{
fmpz_poly_mat_t P1, P2;
slong m = (n1 + n2) / 2;
fmpz_poly_mat_init(P1, P->r, P->c);
fmpz_poly_mat_init(P2, P->r, P->c);
binary_splitting(P1, factors, n1, m);
binary_splitting(P2, factors, m, n2);
fmpz_poly_mat_mul(P, P1, P2);
fmpz_poly_mat_clear(P1);
fmpz_poly_mat_clear(P2);
}
}
void
fmpz_poly_mat_prod(fmpz_poly_mat_t res,
fmpz_poly_mat_t * const factors, slong n)
{
binary_splitting(res, factors, 0, n);
}