pqc/external/flint-2.4.3/fmpz_poly/evaluate_horner_mpq.c
2014-05-24 23:16:06 +02:00

95 lines
2.6 KiB
C

/*=============================================================================
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) 2010 Sebastian Pancratz
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_poly.h"
void
_fmpz_poly_evaluate_horner_mpq(fmpz_t rnum, fmpz_t rden,
const fmpz * f, slong len,
const fmpz_t anum, const fmpz_t aden)
{
if (len == 0)
{
fmpz_zero(rnum);
fmpz_one(rden);
}
else if (len == 1)
{
fmpz_set(rnum, f);
fmpz_one(rden);
}
else
{
slong i = len - 1;
fmpz_t d;
fmpz_init(d);
fmpz_set(rnum, f + i);
fmpz_one(rden);
do
{
--i;
fmpz_mul(rnum, rnum, anum);
fmpz_mul(rden, rden, aden);
{
fmpz_gcd(d, rnum, rden);
fmpz_divexact(rnum, rnum, d);
fmpz_divexact(rden, rden, d);
}
fmpz_addmul(rnum, rden, f + i);
if (*rnum == WORD(0))
fmpz_one(rden);
} while (i);
fmpz_clear(d);
}
}
void
fmpz_poly_evaluate_horner_mpq(mpq_t res, const fmpz_poly_t f, const mpq_t a)
{
fmpz_t rnum, rden, anum, aden;
fmpz_init(rnum);
fmpz_init(rden);
fmpz_init(anum);
fmpz_init(aden);
fmpz_set_mpz(anum, mpq_numref(a));
fmpz_set_mpz(aden, mpq_denref(a));
_fmpz_poly_evaluate_horner_mpq(rnum, rden, f->coeffs, f->length, anum, aden);
fmpz_get_mpz(mpq_numref(res), rnum);
fmpz_get_mpz(mpq_denref(res), rden);
fmpz_clear(rnum);
fmpz_clear(rden);
fmpz_clear(anum);
fmpz_clear(aden);
}