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

148 lines
4.0 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 "fmpz_mod_poly.h"
#include "padic_poly.h"
void _padic_poly_add(fmpz *rop, slong *val, slong N,
const fmpz *op1, slong val1, slong len1, slong N1,
const fmpz *op2, slong val2, slong len2, slong N2,
const padic_ctx_t ctx)
{
const slong len = FLINT_MAX(len1, len2);
*val = FLINT_MIN(val1, val2);
if (val1 == val2)
{
_fmpz_poly_add(rop, op1, len1, op2, len2);
_padic_poly_canonicalise(rop, val, len, ctx->p);
}
else /* => (op1 != op2) */
{
fmpz_t x;
fmpz_init(x);
if (val1 < val2) /* F := p^g (G + p^{h-g} H) */
{
fmpz_pow_ui(x, ctx->p, val2 - val1);
if (rop == op1)
{
_fmpz_vec_zero(rop + len1, len2 - len1);
_fmpz_vec_scalar_addmul_fmpz(rop, op2, len2, x);
}
else
{
_fmpz_vec_scalar_mul_fmpz(rop, op2, len2, x);
_fmpz_poly_add(rop, op1, len1, rop, len2);
}
}
else /* F := p^h (p^{g-h} G + H) */
{
fmpz_pow_ui(x, ctx->p, val1 - val2);
if (rop == op2)
{
_fmpz_vec_zero(rop + len2, len1 - len2);
_fmpz_vec_scalar_addmul_fmpz(rop, op1, len1, x);
}
else
{
_fmpz_vec_scalar_mul_fmpz(rop, op1, len1, x);
_fmpz_poly_add(rop, rop, len1, op2, len2);
}
}
fmpz_clear(x);
}
/* Reduce */
if (N - *val > 0)
{
fmpz_t pow;
int alloc;
alloc = _padic_ctx_pow_ui(pow, N - *val, ctx);
if (N >= N1 && N >= N2)
{
slong i;
for (i = 0; i < len; i++)
if (fmpz_cmpabs(rop + i, pow) >= 0)
fmpz_sub(rop + i, rop + i, pow);
}
else
{
_fmpz_vec_scalar_mod_fmpz(rop, rop, len, pow);
}
if (_fmpz_vec_is_zero(rop, len))
*val = 0;
if (alloc)
fmpz_clear(pow);
}
else
{
_fmpz_vec_zero(rop, len);
*val = 0;
}
}
void padic_poly_add(padic_poly_t f,
const padic_poly_t g, const padic_poly_t h,
const padic_ctx_t ctx)
{
const slong lenG = g->length;
const slong lenH = h->length;
const slong lenF = FLINT_MAX(lenG, lenH);
if (lenG == 0)
{
padic_poly_set(f, h, ctx);
return;
}
if (lenH == 0)
{
padic_poly_set(f, g, ctx);
return;
}
if ((lenG == 0 && lenH == 0) || (FLINT_MIN(g->val, h->val) >= f->N))
{
padic_poly_zero(f);
return;
}
padic_poly_fit_length(f, lenF);
_padic_poly_add(f->coeffs, &(f->val), f->N,
g->coeffs, g->val, lenG, g->N,
h->coeffs, h->val, lenH, h->N, ctx);
_padic_poly_set_length(f, lenF);
_padic_poly_normalise(f);
}