mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
97 lines
2.9 KiB
C
97 lines
2.9 KiB
C
/*
|
|
Copyright (C) 2008, 2009 William Hart
|
|
Copyright (C) 2011 Sebastian Pancratz
|
|
Copyright (C) 2012 Fredrik Johansson
|
|
|
|
This file is part of Arb.
|
|
|
|
Arb is free software: you can redistribute it and/or modify it under
|
|
the terms of the GNU Lesser General Public License (LGPL) as published
|
|
by the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version. See <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "arb_poly.h"
|
|
|
|
void
|
|
_arb_poly_mullow_classical(arb_ptr res,
|
|
arb_srcptr poly1, slong len1,
|
|
arb_srcptr poly2, slong len2, slong n, slong prec)
|
|
{
|
|
len1 = FLINT_MIN(len1, n);
|
|
len2 = FLINT_MIN(len2, n);
|
|
|
|
if (n == 1)
|
|
{
|
|
arb_mul(res, poly1, poly2, prec);
|
|
}
|
|
else if (poly1 == poly2 && len1 == len2)
|
|
{
|
|
slong i;
|
|
|
|
_arb_vec_scalar_mul(res, poly1, FLINT_MIN(len1, n), poly1, prec);
|
|
_arb_vec_scalar_mul(res + len1, poly1 + 1, n - len1, poly1 + len1 - 1, prec);
|
|
|
|
for (i = 1; i < len1 - 1; i++)
|
|
_arb_vec_scalar_addmul(res + i + 1, poly1 + 1,
|
|
FLINT_MIN(i - 1, n - (i + 1)), poly1 + i, prec);
|
|
|
|
for (i = 1; i < FLINT_MIN(2 * len1 - 2, n); i++)
|
|
arb_mul_2exp_si(res + i, res + i, 1);
|
|
|
|
for (i = 1; i < FLINT_MIN(len1 - 1, (n + 1) / 2); i++)
|
|
arb_addmul(res + 2 * i, poly1 + i, poly1 + i, prec);
|
|
}
|
|
else
|
|
{
|
|
slong i;
|
|
|
|
_arb_vec_scalar_mul(res, poly1, FLINT_MIN(len1, n), poly2, prec);
|
|
|
|
if (n > len1)
|
|
_arb_vec_scalar_mul(res + len1, poly2 + 1, n - len1,
|
|
poly1 + len1 - 1, prec);
|
|
|
|
for (i = 0; i < FLINT_MIN(len1, n) - 1; i++)
|
|
_arb_vec_scalar_addmul(res + i + 1, poly2 + 1,
|
|
FLINT_MIN(len2, n - i) - 1,
|
|
poly1 + i, prec);
|
|
}
|
|
}
|
|
|
|
void
|
|
arb_poly_mullow_classical(arb_poly_t res, const arb_poly_t poly1,
|
|
const arb_poly_t poly2,
|
|
slong n, slong prec)
|
|
{
|
|
slong len_out;
|
|
|
|
if (poly1->length == 0 || poly2->length == 0 || n == 0)
|
|
{
|
|
arb_poly_zero(res);
|
|
return;
|
|
}
|
|
|
|
len_out = poly1->length + poly2->length - 1;
|
|
if (n > len_out)
|
|
n = len_out;
|
|
|
|
if (res == poly1 || res == poly2)
|
|
{
|
|
arb_poly_t t;
|
|
arb_poly_init2(t, n);
|
|
_arb_poly_mullow_classical(t->coeffs, poly1->coeffs, poly1->length,
|
|
poly2->coeffs, poly2->length, n, prec);
|
|
arb_poly_swap(res, t);
|
|
arb_poly_clear(t);
|
|
}
|
|
else
|
|
{
|
|
arb_poly_fit_length(res, n);
|
|
_arb_poly_mullow_classical(res->coeffs, poly1->coeffs, poly1->length,
|
|
poly2->coeffs, poly2->length, n, prec);
|
|
}
|
|
|
|
_arb_poly_set_length(res, n);
|
|
_arb_poly_normalise(res);
|
|
}
|