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

90 lines
2.5 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) 2012 Sebastian Pancratz
******************************************************************************/
#include "fmpz_mod_poly.h"
#include "padic_poly.h"
void _padic_poly_pow(fmpz *rop, slong *rval, slong N,
const fmpz *op, slong val, slong len, ulong e,
const padic_ctx_t ctx)
{
fmpz_t pow;
int alloc;
*rval = (slong) e * val;
alloc = _padic_ctx_pow_ui(pow, N - *rval, ctx);
_fmpz_mod_poly_pow(rop, op, len, e, pow);
if (alloc)
fmpz_clear(pow);
}
void padic_poly_pow(padic_poly_t rop, const padic_poly_t op, ulong e,
const padic_ctx_t ctx)
{
if (e == 0)
{
padic_poly_one(rop);
}
else if (op->length == 0 || (slong) e * op->val >= rop->N)
{
padic_poly_zero(rop);
}
else if (e == 1)
{
padic_poly_set(rop, op, ctx);
}
else
{
const slong rlen = (slong) e * (op->length - 1) + 1;
fmpz *t;
if (rop == op)
{
t = _fmpz_vec_init(rlen);
}
else
{
padic_poly_fit_length(rop, rlen);
t = rop->coeffs;
}
_padic_poly_pow(t, &(rop->val), rop->N,
op->coeffs, op->val, op->length, e, ctx);
if (rop == op)
{
_fmpz_vec_clear(rop->coeffs, rop->alloc);
rop->coeffs = t;
rop->alloc = rlen;
}
_padic_poly_set_length(rop, rlen);
_padic_poly_normalise(rop);
}
}