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/*
Copyright (C) 2017 Fredrik Johansson
This file is part of FLINT.
FLINT 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 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "arb.h"
void
arb_nonnegative_part(arb_t res, const arb_t x)
{
if (!arb_contains_negative(x))
{
arb_set(res, x);
}
else if (!arb_is_finite(x))
{
arb_indeterminate(res);
}
else
{
arf_t t;
arf_init(t);
arf_set_mag(t, arb_radref(x));
arf_add(arb_midref(res), arb_midref(x), t, MAG_BITS, ARF_RND_CEIL);
if (arf_sgn(arb_midref(res)) <= 0)
{
arf_zero(arb_midref(res));
mag_zero(arb_radref(res));
}
else
{
arf_mul_2exp_si(arb_midref(res), arb_midref(res), -1);
arf_get_mag(arb_radref(res), arb_midref(res));
/* needed since arf_get_mag is inexact */
arf_set_mag(arb_midref(res), arb_radref(res));
}
arf_clear(t);
}
}