mirror of
https://github.com/vale981/arb
synced 2025-03-06 01:41:39 -05:00
122 lines
3.6 KiB
C
122 lines
3.6 KiB
C
/*=============================================================================
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This file is part of ARB.
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ARB is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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ARB is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with ARB; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2012 Fredrik Johansson
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******************************************************************************/
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#include "acb_poly.h"
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void
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_acb_poly_compose_series(acb_ptr res, acb_srcptr poly1, slong len1,
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acb_srcptr poly2, slong len2, slong n, slong prec)
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{
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if (len2 == 1)
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{
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acb_set_round(res, poly1, prec);
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_acb_vec_zero(res + 1, n - 1);
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}
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else if (_acb_vec_is_zero(poly2 + 1, len2 - 2)) /* poly2 is a monomial */
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{
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slong i, j;
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acb_t t;
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acb_init(t);
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acb_set(t, poly2 + len2 - 1);
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acb_set_round(res, poly1, prec);
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for (i = 1, j = len2 - 1; i < len1 && j < n; i++, j += len2 - 1)
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{
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acb_mul(res + j, poly1 + i, t, prec);
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if (i + 1 < len1 && j + len2 - 1 < n)
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acb_mul(t, t, poly2 + len2 - 1, prec);
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}
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if (len2 != 2)
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for (i = 1; i < n; i++)
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if (i % (len2 - 1) != 0)
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acb_zero(res + i);
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acb_clear(t);
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}
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else if (len1 < 6 || n < 6)
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{
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_acb_poly_compose_series_horner(res, poly1, len1, poly2, len2, n, prec);
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}
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else
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{
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_acb_poly_compose_series_brent_kung(res, poly1, len1, poly2, len2, n, prec);
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}
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}
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void
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acb_poly_compose_series(acb_poly_t res,
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const acb_poly_t poly1,
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const acb_poly_t poly2, slong n, slong prec)
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{
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slong len1 = poly1->length;
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slong len2 = poly2->length;
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slong lenr;
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if (len2 != 0 && !acb_is_zero(poly2->coeffs))
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{
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printf("exception: compose_series: inner "
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"polynomial must have zero constant term\n");
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abort();
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}
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if (len1 == 0 || n == 0)
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{
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acb_poly_zero(res);
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return;
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}
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if (len2 == 0 || len1 == 1)
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{
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acb_poly_set_acb(res, poly1->coeffs);
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return;
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}
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lenr = FLINT_MIN((len1 - 1) * (len2 - 1) + 1, n);
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len1 = FLINT_MIN(len1, lenr);
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len2 = FLINT_MIN(len2, lenr);
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if ((res != poly1) && (res != poly2))
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{
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acb_poly_fit_length(res, lenr);
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_acb_poly_compose_series(res->coeffs, poly1->coeffs, len1,
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poly2->coeffs, len2, lenr, prec);
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_acb_poly_set_length(res, lenr);
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_acb_poly_normalise(res);
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}
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else
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{
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acb_poly_t t;
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acb_poly_init2(t, lenr);
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_acb_poly_compose_series(t->coeffs, poly1->coeffs, len1,
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poly2->coeffs, len2, lenr, prec);
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_acb_poly_set_length(t, lenr);
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_acb_poly_normalise(t);
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acb_poly_swap(res, t);
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acb_poly_clear(t);
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}
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}
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