arb/acb/csch.c

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/*
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_csch(acb_t res, const acb_t z, slong prec)
{
if (acb_contains_zero(z) || !acb_is_finite(z))
{
acb_indeterminate(res);
}
else if (arb_is_zero(acb_imagref(z)))
{
arb_csch(acb_realref(res), acb_realref(z), prec);
arb_zero(acb_imagref(res));
}
else if (arb_is_zero(acb_realref(z)))
{
arb_csc(acb_imagref(res), acb_imagref(z), prec);
arb_neg(acb_imagref(res), acb_imagref(res));
arb_zero(acb_realref(res));
}
else
{
if (arf_cmpabs_2exp_si(arb_midref(acb_realref(z)), 0) > 0)
{
acb_t t;
acb_init(t);
if (arf_sgn(arb_midref(acb_realref(z))) > 0)
{
acb_neg(t, z);
acb_exp(t, t, prec + 4);
acb_mul(res, t, t, prec + 4);
acb_sub_ui(res, res, 1, prec + 4);
acb_div(res, t, res, prec);
acb_neg(res, res);
}
else
{
acb_exp(t, z, prec + 4);
acb_mul(res, t, t, prec + 4);
acb_sub_ui(res, res, 1, prec + 4);
acb_div(res, t, res, prec);
}
acb_mul_2exp_si(res, res, 1);
acb_clear(t);
}
else
{
acb_sinh(res, z, prec + 4);
acb_inv(res, res, prec);
}
}
}