mirror of
https://github.com/vale981/arb
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73 lines
1.6 KiB
C
73 lines
1.6 KiB
C
/*
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Copyright (C) 2013 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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void
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_acb_poly_evaluate2_horner(acb_t y, acb_t z, acb_srcptr poly,
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slong len, const acb_t x, slong prec)
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{
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if (len == 0)
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{
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acb_zero(y);
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acb_zero(z);
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}
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else if (len == 1)
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{
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acb_set_round(y, poly + 0, prec);
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acb_zero(z);
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}
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else if (acb_is_zero(x))
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{
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acb_set_round(y, poly + 0, prec);
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acb_set_round(z, poly + 1, prec);
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}
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else if (len == 2)
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{
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acb_mul(y, x, poly + 1, prec);
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acb_add(y, y, poly + 0, prec);
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acb_set_round(z, poly + 1, prec);
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}
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else
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{
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acb_t t, u, v;
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slong i;
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acb_init(t);
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acb_init(u);
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acb_init(v);
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acb_set_round(u, poly + len - 1, prec);
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acb_zero(v);
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for (i = len - 2; i >= 0; i--)
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{
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acb_mul(t, v, x, prec);
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acb_add(v, u, t, prec);
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acb_mul(t, u, x, prec);
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acb_add(u, t, poly + i, prec);
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}
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acb_swap(y, u);
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acb_swap(z, v);
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acb_clear(t);
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acb_clear(u);
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acb_clear(v);
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}
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}
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void
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acb_poly_evaluate2_horner(acb_t r, acb_t s, const acb_poly_t f, const acb_t a, slong prec)
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{
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_acb_poly_evaluate2_horner(r, s, f->coeffs, f->length, a, prec);
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}
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