mirror of
https://github.com/vale981/arb
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59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
/*
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Copyright (C) 2010 Sebastian Pancratz
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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 "arb_poly.h"
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void
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_arb_poly_evaluate_horner(arb_t y, arb_srcptr f, slong len,
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const arb_t x, slong prec)
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{
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if (len == 0)
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{
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arb_zero(y);
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}
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else if (len == 1 || arb_is_zero(x))
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{
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arb_set_round(y, f, prec);
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}
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else if (len == 2)
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{
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arb_mul(y, x, f + 1, prec);
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arb_add(y, y, f + 0, prec);
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}
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else
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{
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slong i = len - 1;
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arb_t t, u;
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arb_init(t);
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arb_init(u);
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arb_set(u, f + i);
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for (i = len - 2; i >= 0; i--)
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{
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arb_mul(t, u, x, prec);
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arb_add(u, f + i, t, prec);
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}
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arb_swap(y, u);
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arb_clear(t);
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arb_clear(u);
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}
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}
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void
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arb_poly_evaluate_horner(arb_t res, const arb_poly_t f, const arb_t a, slong prec)
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{
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_arb_poly_evaluate_horner(res, f->coeffs, f->length, a, prec);
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}
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