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

90 lines
2.7 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, 2012 Sebastian Pancratz
******************************************************************************/
#include "padic_poly.h"
void padic_poly_set_coeff_padic(padic_poly_t poly, slong n, const padic_t x,
const padic_ctx_t ctx)
{
if (padic_is_zero(x) || padic_val(x) >= padic_poly_prec(poly))
{
if (n < poly->length)
{
fmpz_zero(poly->coeffs + n);
padic_poly_canonicalise(poly, ctx->p);
}
return;
}
padic_poly_fit_length(poly, n + 1);
if (n + 1 > poly->length)
{
mpn_zero((mp_ptr) (poly->coeffs + poly->length), n - poly->length);
poly->length = n + 1;
}
if (padic_val(x) == poly->val)
{
fmpz_set(poly->coeffs + n, padic_unit(x));
}
else if (poly->val < padic_val(x))
{
fmpz_t y;
fmpz_init(y);
fmpz_pow_ui(y, ctx->p, padic_val(x) - poly->val);
fmpz_mul(poly->coeffs + n, padic_unit(x), y);
fmpz_clear(y);
padic_poly_canonicalise(poly, ctx->p);
}
else /* poly->val > x->val */
{
fmpz_t pow;
fmpz_init(pow);
fmpz_pow_ui(pow, ctx->p, poly->val - padic_val(x));
_fmpz_vec_scalar_mul_fmpz(poly->coeffs,
poly->coeffs, poly->length, pow);
fmpz_set(poly->coeffs + n, padic_unit(x));
fmpz_clear(pow);
poly->val = padic_val(x);
}
if (padic_poly_prec(poly) < padic_prec(x)) /* Reduction? */
{
int c;
fmpz_t pow;
c = _padic_ctx_pow_ui(pow, padic_poly_prec(poly) - padic_poly_val(poly), ctx);
fmpz_mod(poly->coeffs + n, poly->coeffs + n, pow);
if (c)
fmpz_clear(pow);
}
_padic_poly_normalise(poly);
}