mirror of
https://github.com/vale981/arb
synced 2025-03-06 09:51:39 -05:00
111 lines
3.5 KiB
C
111 lines
3.5 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) 2008, 2009 William Hart
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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_mullow_classical(acb_ptr res,
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acb_srcptr poly1, long len1,
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acb_srcptr poly2, long len2, long n, long prec)
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{
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len1 = FLINT_MIN(len1, n);
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len2 = FLINT_MIN(len2, n);
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if (n == 1)
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{
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acb_mul(res, poly1, poly2, prec);
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}
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else if (poly1 == poly2 && len1 == len2)
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{
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long i;
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_acb_vec_scalar_mul(res, poly1, FLINT_MIN(len1, n), poly1, prec);
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_acb_vec_scalar_mul(res + len1, poly1 + 1, n - len1, poly1 + len1 - 1, prec);
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for (i = 1; i < len1 - 1; i++)
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_acb_vec_scalar_addmul(res + i + 1, poly1 + 1,
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FLINT_MIN(i - 1, n - (i + 1)), poly1 + i, prec);
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for (i = 1; i < FLINT_MIN(2 * len1 - 2, n); i++)
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acb_mul_2exp_si(res + i, res + i, 1);
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for (i = 1; i < FLINT_MIN(len1 - 1, (n + 1) / 2); i++)
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acb_addmul(res + 2 * i, poly1 + i, poly1 + i, prec);
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}
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else
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{
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long i;
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_acb_vec_scalar_mul(res, poly1, FLINT_MIN(len1, n), poly2, prec);
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if (n > len1)
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_acb_vec_scalar_mul(res + len1, poly2 + 1, n - len1,
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poly1 + len1 - 1, prec);
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for (i = 0; i < FLINT_MIN(len1, n) - 1; i++)
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_acb_vec_scalar_addmul(res + i + 1, poly2 + 1,
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FLINT_MIN(len2, n - i) - 1,
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poly1 + i, prec);
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}
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}
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void
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acb_poly_mullow_classical(acb_poly_t res, const acb_poly_t poly1,
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const acb_poly_t poly2,
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long n, long prec)
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{
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long len_out;
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if (poly1->length == 0 || poly2->length == 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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len_out = poly1->length + poly2->length - 1;
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if (n > len_out)
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n = len_out;
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if (res == poly1 || res == poly2)
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{
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acb_poly_t t;
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acb_poly_init2(t, n);
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_acb_poly_mullow_classical(t->coeffs, poly1->coeffs, poly1->length,
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poly2->coeffs, poly2->length, n, prec);
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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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else
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{
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acb_poly_fit_length(res, n);
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_acb_poly_mullow_classical(res->coeffs, poly1->coeffs, poly1->length,
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poly2->coeffs, poly2->length, n, prec);
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}
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_acb_poly_set_length(res, n);
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_acb_poly_normalise(res);
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}
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