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

213 lines
6.4 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) 2013 Martin Lee
Copyright (C) 2013 Mike Hansen
******************************************************************************/
#ifdef T
#include "templates.h"
#include "long_extras.h"
void
_TEMPLATE(T, poly_powmod_x_fmpz_preinv) (
TEMPLATE(T, struct) * res,
const fmpz_t e,
const TEMPLATE(T, struct) * f, slong lenf,
const TEMPLATE(T, struct) * finv, slong lenfinv,
const TEMPLATE(T, ctx_t) ctx)
{
TEMPLATE(T, struct) * T, *Q;
slong lenT, lenQ;
slong i, window, l, c;
lenT = 2 * lenf - 3;
lenQ = lenT - lenf + 1;
T = _TEMPLATE(T, vec_init) (lenT + lenQ, ctx);
Q = T + lenT;
TEMPLATE(T, one) (res, ctx);
l = z_sizeinbase(lenf - 1, 2) - 2;
window = 0;
window = (1 << l);
c = l;
i = fmpz_sizeinbase(e, 2) - 2;
if (i <= l)
{
window = 0;
window = (1 << i);
c = i;
l = i;
}
if (c == 0)
{
_TEMPLATE(T, poly_shift_left) (T, res, lenf - 1, window, ctx);
_TEMPLATE(T, poly_divrem_newton_n_preinv) (Q, res, T,
lenf - 1 + window, f, lenf,
finv, lenfinv, ctx);
c = l + 1;
window = 0;
}
for (; i >= 0; i--)
{
_TEMPLATE(T, poly_sqr) (T, res, lenf - 1, ctx);
_TEMPLATE(T, poly_divrem_newton_n_preinv) (Q, res, T, 2 * lenf - 3, f,
lenf, finv, lenfinv, ctx);
c--;
if (fmpz_tstbit(e, i))
{
if (window == 0 && i <= l - 1)
c = i;
if (c >= 0)
window = window | (1 << c);
}
else if (window == 0)
{
c = l + 1;
}
if (c == 0)
{
_TEMPLATE(T, poly_shift_left) (T, res, lenf - 1, window, ctx);
_TEMPLATE(T, poly_divrem_newton_n_preinv) (Q, res, T,
lenf - 1 + window, f,
lenf, finv, lenfinv,
ctx);
c = l + 1;
window = 0;
}
}
_TEMPLATE(T, vec_clear) (T, lenT + lenQ, ctx);
}
void
TEMPLATE(T, poly_powmod_x_fmpz_preinv) (TEMPLATE(T, poly_t) res,
const fmpz_t e,
const TEMPLATE(T, poly_t) f,
const TEMPLATE(T, poly_t) finv,
const TEMPLATE(T, ctx_t) ctx)
{
slong lenf = f->length;
slong trunc = lenf - 1;
TEMPLATE(T, poly_t) tmp;
if (lenf == 0)
{
TEMPLATE_PRINTF("Exception: %s_poly_powmod_x_preinv:", T);
flint_printf(" divide by zero\n");
abort();
}
if (fmpz_sgn(e) < 0)
{
TEMPLATE_PRINTF("Exception: %s_poly_powmod_x_preinv: ", T);
flint_printf(" negative exp not implemented\n");
abort();
}
if (lenf == 1)
{
TEMPLATE(T, poly_zero) (res, ctx);
return;
}
if (lenf == 2)
{
TEMPLATE(T, poly_t) r, poly;
TEMPLATE(T, poly_init) (tmp, ctx);
TEMPLATE(T, poly_init) (r, ctx);
TEMPLATE(T, poly_init2) (poly, 2, ctx);
TEMPLATE(T, poly_gen) (poly, ctx);
TEMPLATE(T, poly_divrem) (tmp, r, poly, f, ctx);
TEMPLATE(T, poly_powmod_fmpz_binexp_preinv) (res, r, e, f, finv, ctx);
TEMPLATE(T, poly_clear) (tmp, ctx);
TEMPLATE(T, poly_clear) (r, ctx);
TEMPLATE(T, poly_clear) (poly, ctx);
return;
}
if (fmpz_abs_fits_ui(e))
{
ulong exp = fmpz_get_ui(e);
if (exp <= 2)
{
if (exp == UWORD(0))
{
TEMPLATE(T, poly_fit_length) (res, 1, ctx);
TEMPLATE(T, one) (res->coeffs, ctx);
_TEMPLATE(T, poly_set_length) (res, 1, ctx);
}
else if (exp == UWORD(1))
{
TEMPLATE(T, poly_t) r;
TEMPLATE(T, poly_init2) (r, 2, ctx);
TEMPLATE(T, poly_gen) (r, ctx);
TEMPLATE(T, poly_init) (tmp, ctx);
TEMPLATE(T, poly_divrem) (tmp, res, r, f, ctx);
TEMPLATE(T, poly_clear) (tmp, ctx);
TEMPLATE(T, poly_clear) (r, ctx);
}
else
{
TEMPLATE(T, poly_init2) (tmp, 3, ctx);
TEMPLATE(T, poly_gen) (tmp, ctx);
TEMPLATE(T, poly_mulmod) (res, tmp, tmp, f, ctx);
TEMPLATE(T, poly_clear) (tmp, ctx);
}
return;
}
}
if ((res == f) || (res == finv))
{
TEMPLATE(T, poly_init2) (tmp, trunc, ctx);
_TEMPLATE(T, poly_powmod_x_fmpz_preinv) (tmp->coeffs, e, f->coeffs,
lenf, finv->coeffs,
finv->length, ctx);
TEMPLATE(T, poly_swap) (res, tmp, ctx);
TEMPLATE(T, poly_clear) (tmp, ctx);
}
else
{
TEMPLATE(T, poly_fit_length) (res, trunc, ctx);
_TEMPLATE(T, poly_powmod_x_fmpz_preinv) (res->coeffs, e, f->coeffs,
lenf, finv->coeffs,
finv->length, ctx);
}
_TEMPLATE(T, poly_set_length) (res, trunc, ctx);
_TEMPLATE(T, poly_normalise) (res, ctx);
}
#endif