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

156 lines
4.3 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) 2011 Fredrik Johansson
Copyright (C) 2012 Lina Kulakova
Copyright (C) 2013 Mike Hansen
******************************************************************************/
#ifdef T
#include "templates.h"
#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"
void
_TEMPLATE(T, poly_compose_mod_horner) (
TEMPLATE(T, struct) * res,
const TEMPLATE(T, struct) * f, slong lenf,
const TEMPLATE(T, struct) * g,
const TEMPLATE(T, struct) * h, slong lenh,
const TEMPLATE(T, ctx_t) ctx)
{
slong i, len;
TEMPLATE(T, struct) * t;
if (lenh == 1)
return;
if (lenf == 1)
{
TEMPLATE(T, set) (res, f, ctx);
return;
}
if (lenh == 2)
{
_TEMPLATE(T, TEMPLATE(poly_evaluate, T)) (res, f, lenf, g, ctx);
return;
}
len = lenh - 1;
i = lenf - 1;
t = _TEMPLATE(T, vec_init) (2 * lenh - 3, ctx);
_TEMPLATE(T, TEMPLATE(poly_scalar_mul, T)) (res, g, len, f + i, ctx);
i--;
if (i >= 0)
{
TEMPLATE(T, add) (res, res, f + i, ctx);
}
while (i > 0)
{
i--;
_TEMPLATE(T, poly_mulmod) (t, res, len, g, len, h, lenh, ctx);
_TEMPLATE(T, poly_add) (res, t, len, f + i, 1, ctx);
}
_TEMPLATE(T, vec_clear) (t, 2 * lenh - 3, ctx);
}
void
TEMPLATE(T, poly_compose_mod_horner) (TEMPLATE(T, poly_t) res,
const TEMPLATE(T, poly_t) poly1,
const TEMPLATE(T, poly_t) poly2,
const TEMPLATE(T, poly_t) poly3,
const TEMPLATE(T, ctx_t) ctx)
{
TEMPLATE(T, t) inv3;
slong len1 = poly1->length;
slong len2 = poly2->length;
slong len3 = poly3->length;
slong len = len3 - 1;
slong vec_len = FLINT_MAX(len3 - 1, len2);
TEMPLATE(T, struct) * ptr2;
if (len3 == 0)
{
TEMPLATE_PRINTF
("Exception: division by zero in %s_poly_compose_mod_horner\n", T);
abort();
}
if (len1 == 0 || len3 == 1)
{
TEMPLATE(T, poly_zero) (res, ctx);
return;
}
if (len1 == 1)
{
TEMPLATE(T, poly_set) (res, poly1, ctx);
return;
}
if (res == poly3 || res == poly1)
{
TEMPLATE(T, poly_t) tmp;
TEMPLATE(T, poly_init) (tmp, ctx);
TEMPLATE(T, poly_compose_mod_horner) (tmp, poly1, poly2, poly3, ctx);
TEMPLATE(T, poly_swap) (tmp, res, ctx);
TEMPLATE(T, poly_clear) (tmp, ctx);
return;
}
ptr2 = _TEMPLATE(T, vec_init) (vec_len, ctx);
if (len2 <= len3 - 1)
{
_TEMPLATE(T, vec_set) (ptr2, poly2->coeffs, len2, ctx);
_TEMPLATE(T, vec_zero) (ptr2 + len2, vec_len - len2, ctx);
}
else
{
TEMPLATE(T, init) (inv3, ctx);
TEMPLATE(T, inv) (inv3, poly3->coeffs + len, ctx);
_TEMPLATE(T, poly_rem) (ptr2, poly2->coeffs, len2,
poly3->coeffs, len3, inv3, ctx);
TEMPLATE(T, clear) (inv3, ctx);
}
TEMPLATE(T, poly_fit_length) (res, len, ctx);
_TEMPLATE(T, poly_compose_mod_horner) (res->coeffs,
poly1->coeffs, len1,
ptr2, poly3->coeffs, len3, ctx);
_TEMPLATE(T, poly_set_length) (res, len, ctx);
_TEMPLATE(T, poly_normalise) (res, ctx);
_TEMPLATE(T, vec_clear) (ptr2, vec_len, ctx);
}
#endif