138 lines
3.9 KiB
C
138 lines
3.9 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 Fredrik Johansson
|
|
|
|
******************************************************************************/
|
|
|
|
#include <gmp.h>
|
|
#include "flint.h"
|
|
#include "fmpz.h"
|
|
#include "fmpz_poly.h"
|
|
#include "fmpz_mat.h"
|
|
#include "ulong_extras.h"
|
|
|
|
void
|
|
_fmpz_poly_compose_series_brent_kung(fmpz * res, const fmpz * poly1, slong len1,
|
|
const fmpz * poly2, slong len2, slong n)
|
|
{
|
|
fmpz_mat_t A, B, C;
|
|
fmpz *t, *h;
|
|
slong i, m;
|
|
|
|
if (n == 1)
|
|
{
|
|
fmpz_set(res, poly1);
|
|
return;
|
|
}
|
|
|
|
m = n_sqrt(n) + 1;
|
|
|
|
fmpz_mat_init(A, m, n);
|
|
fmpz_mat_init(B, m, m);
|
|
fmpz_mat_init(C, m, n);
|
|
|
|
h = _fmpz_vec_init(n);
|
|
t = _fmpz_vec_init(n);
|
|
|
|
/* Set rows of B to the segments of poly1 */
|
|
for (i = 0; i < len1 / m; i++)
|
|
_fmpz_vec_set(B->rows[i], poly1 + i*m, m);
|
|
_fmpz_vec_set(B->rows[i], poly1 + i*m, len1 % m);
|
|
|
|
/* Set rows of A to powers of poly2 */
|
|
fmpz_one(A->rows[0]);
|
|
_fmpz_vec_set(A->rows[1], poly2, len2);
|
|
for (i = 2; i < m; i++)
|
|
_fmpz_poly_mullow(A->rows[i], A->rows[i-1], n, poly2, len2, n);
|
|
|
|
fmpz_mat_mul(C, B, A);
|
|
|
|
/* Evaluate block composition using the Horner scheme */
|
|
_fmpz_vec_set(res, C->rows[m - 1], n);
|
|
_fmpz_poly_mullow(h, A->rows[m - 1], n, poly2, len2, n);
|
|
|
|
for (i = m - 2; i >= 0; i--)
|
|
{
|
|
_fmpz_poly_mullow(t, res, n, h, n, n);
|
|
_fmpz_poly_add(res, t, n, C->rows[i], n);
|
|
}
|
|
|
|
_fmpz_vec_clear(h, n);
|
|
_fmpz_vec_clear(t, n);
|
|
|
|
fmpz_mat_clear(A);
|
|
fmpz_mat_clear(B);
|
|
fmpz_mat_clear(C);
|
|
}
|
|
|
|
void
|
|
fmpz_poly_compose_series_brent_kung(fmpz_poly_t res,
|
|
const fmpz_poly_t poly1, const fmpz_poly_t poly2, slong n)
|
|
{
|
|
slong len1 = poly1->length;
|
|
slong len2 = poly2->length;
|
|
slong lenr;
|
|
|
|
if (len2 != 0 && !fmpz_is_zero(poly2->coeffs))
|
|
{
|
|
flint_printf("Exception (fmpz_poly_compose_series_brent_kung). Inner \n"
|
|
"polynomial must have zero constant term.\n");
|
|
abort();
|
|
}
|
|
|
|
if (len1 == 0 || n == 0)
|
|
{
|
|
fmpz_poly_zero(res);
|
|
return;
|
|
}
|
|
|
|
if (len2 == 0 || len1 == 1)
|
|
{
|
|
fmpz_poly_set_fmpz(res, poly1->coeffs);
|
|
return;
|
|
}
|
|
|
|
lenr = FLINT_MIN((len1 - 1) * (len2 - 1) + 1, n);
|
|
len1 = FLINT_MIN(len1, lenr);
|
|
len2 = FLINT_MIN(len2, lenr);
|
|
|
|
if ((res != poly1) && (res != poly2))
|
|
{
|
|
fmpz_poly_fit_length(res, lenr);
|
|
_fmpz_poly_compose_series_brent_kung(res->coeffs, poly1->coeffs, len1,
|
|
poly2->coeffs, len2, lenr);
|
|
_fmpz_poly_set_length(res, lenr);
|
|
_fmpz_poly_normalise(res);
|
|
}
|
|
else
|
|
{
|
|
fmpz_poly_t t;
|
|
fmpz_poly_init2(t, lenr);
|
|
_fmpz_poly_compose_series_brent_kung(t->coeffs, poly1->coeffs, len1,
|
|
poly2->coeffs, len2, lenr);
|
|
_fmpz_poly_set_length(t, lenr);
|
|
_fmpz_poly_normalise(t);
|
|
fmpz_poly_swap(res, t);
|
|
fmpz_poly_clear(t);
|
|
}
|
|
}
|