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/*
Copyright (C) 2010 Sebastian Pancratz
Copyright (C) 2012 Fredrik Johansson
This file is part of Arb.
Arb is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version. See <http://www.gnu.org/licenses/>.
*/
#include "acb_poly.h"
void
_acb_poly_evaluate_horner(acb_t y, acb_srcptr f, slong len,
const acb_t x, slong prec)
{
if (len == 0)
{
acb_zero(y);
}
else if (len == 1 || acb_is_zero(x))
{
acb_set_round(y, f, prec);
}
else if (len == 2)
{
acb_mul(y, x, f + 1, prec);
acb_add(y, y, f + 0, prec);
}
else
{
slong i = len - 1;
acb_t t, u;
acb_init(t);
acb_init(u);
acb_set(u, f + i);
for (i = len - 2; i >= 0; i--)
{
acb_mul(t, u, x, prec);
acb_add(u, f + i, t, prec);
}
acb_swap(y, u);
acb_clear(t);
acb_clear(u);
}
}
void
acb_poly_evaluate_horner(acb_t res, const acb_poly_t f, const acb_t a, slong prec)
{
_acb_poly_evaluate_horner(res, f->coeffs, f->length, a, prec);
}
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