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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 "arb_fmpz_poly.h"
void
_arb_fmpz_poly_evaluate_arb_horner(arb_t y, const fmpz * f, slong len,
const arb_t x, slong prec)
{
if (len == 0)
{
arb_zero(y);
}
else if (len == 1 || arb_is_zero(x))
{
arb_set_round_fmpz(y, f, prec);
}
else if (len == 2)
{
arb_mul_fmpz(y, x, f + 1, prec);
arb_add_fmpz(y, y, f + 0, prec);
}
else
{
slong i = len - 1;
arb_t t, u;
arb_init(t);
arb_init(u);
arb_set_fmpz(u, f + i);
for (i = len - 2; i >= 0; i--)
{
arb_mul(t, u, x, prec);
arb_add_fmpz(u, t, f + i, prec);
}
arb_swap(y, u);
arb_clear(t);
arb_clear(u);
}
}
void
arb_fmpz_poly_evaluate_arb_horner(arb_t res, const fmpz_poly_t f, const arb_t a, slong prec)
{
_arb_fmpz_poly_evaluate_arb_horner(res, f->coeffs, f->length, a, prec);
}
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