arb/acb/acosh.c
2018-03-04 10:00:18 +01:00

57 lines
1.3 KiB
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_acosh(acb_t res, const acb_t z, slong prec)
{
if (acb_is_one(z))
{
acb_zero(res);
}
else
{
acb_t t, u;
acb_init(t);
acb_init(u);
acb_add_ui(t, z, 1, prec);
acb_sub_ui(u, z, 1, prec);
acb_sqrt(t, t, prec);
acb_sqrt(u, u, prec);
acb_mul(t, t, u, prec);
acb_add(t, t, z, prec);
if (!arb_is_zero(acb_imagref(z)))
{
acb_log(res, t, prec);
acb_clear(t);
acb_clear(u);
return;
}
arb_t one, abs;
arb_init(one);
arb_init(abs);
arb_one(one);
arb_abs(abs, acb_realref(z));
acb_log(res, t, prec);
if (arb_lt(abs, one))
{
arb_zero(acb_realref(res));
}
acb_clear(t);
acb_clear(u);
arb_clear(one);
arb_clear(abs);
}
}