mirror of
https://github.com/vale981/arb
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109 lines
3.1 KiB
C
109 lines
3.1 KiB
C
/*
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Copyright (C) 2012 Fredrik Johansson
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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 it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version. See <http://www.gnu.org/licenses/>.
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*/
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#include "acb_poly.h"
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#define CUTOFF 4
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void
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_acb_poly_mullow(acb_ptr res,
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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 (n < CUTOFF || len1 < CUTOFF || len2 < CUTOFF)
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_acb_poly_mullow_classical(res, poly1, len1, poly2, len2, n, prec);
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else
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_acb_poly_mullow_transpose(res, poly1, len1, poly2, len2, n, prec);
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}
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void
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acb_poly_mullow(acb_poly_t res, 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, len2;
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len1 = poly1->length;
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len2 = poly2->length;
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if (len1 == 0 || len2 == 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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n = FLINT_MIN((len1 + len2 - 1), n);
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len1 = FLINT_MIN(len1, n);
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len2 = FLINT_MIN(len2, n);
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/* Hack to avoid temporary allocations with first derivatives. */
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if (n <= 2 && !(len1 == 2 && len2 == 2))
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{
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acb_poly_fit_length(res, n);
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if (n == 1)
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{
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acb_mul(res->coeffs, poly1->coeffs, poly2->coeffs, prec);
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}
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else if (len2 == 1)
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{
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acb_mul(res->coeffs + 1, poly1->coeffs + 1, poly2->coeffs, prec);
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acb_mul(res->coeffs, poly1->coeffs, poly2->coeffs, prec);
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}
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else if (len1 == 1)
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{
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acb_mul(res->coeffs + 1, poly2->coeffs + 1, poly1->coeffs, prec);
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acb_mul(res->coeffs, poly2->coeffs, poly1->coeffs, prec);
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}
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else
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{
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if (res == poly1 || res == poly2)
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{
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acb_t t;
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acb_init(t);
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acb_mul(t, poly1->coeffs, poly2->coeffs + 1, prec);
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acb_addmul(t, poly2->coeffs, poly1->coeffs + 1, prec);
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acb_mul(res->coeffs, poly1->coeffs, poly2->coeffs, prec);
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acb_swap(t, res->coeffs + 1);
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acb_clear(t);
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}
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else
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{
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acb_mul(res->coeffs, poly1->coeffs, poly2->coeffs, prec);
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acb_mul(res->coeffs + 1, poly1->coeffs, poly2->coeffs + 1, prec);
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acb_addmul(res->coeffs + 1, poly2->coeffs, poly1->coeffs + 1, prec);
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}
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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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return;
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}
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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(t->coeffs, poly1->coeffs, len1,
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poly2->coeffs, len2, 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(res->coeffs, poly1->coeffs, len1,
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poly2->coeffs, len2, 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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