arb/acb/acos.c
2016-04-26 17:20:05 +02:00

32 lines
728 B
C

/*
Copyright (C) 2015 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.h"
void
acb_acos(acb_t res, const acb_t z, slong prec)
{
if (acb_is_one(z))
{
acb_zero(res);
}
else
{
acb_t t;
acb_init(t);
acb_asin(res, z, prec);
acb_const_pi(t, prec);
acb_mul_2exp_si(t, t, -1);
acb_sub(res, t, res, prec);
acb_clear(t);
}
}