xref: /openbsd-src/lib/libm/src/s_cacosh.c (revision 2f2c00629eff6a304ebffb255fc56f4fa7a1833b)

/*	$OpenBSD: s_cacosh.c,v 1.8 2016/09/12 19:47:02 guenther Exp $	*/
/*
 * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*							cacosh
 *
 *	Complex inverse hyperbolic cosine
 *
 *
 *
 * SYNOPSIS:
 *
 * double complex cacosh();
 * double complex z, w;
 *
 * w = cacosh (z);
 *
 *
 *
 * DESCRIPTION:
 *
 * acosh z = i acos z .
 *
 * ACCURACY:
 *
 *                      Relative error:
 * arithmetic   domain     # trials      peak         rms
 *    IEEE      -10,+10     30000       1.6e-14     2.1e-15
 *
 */

#include <complex.h>
#include <float.h>
#include <math.h>

double complex
cacosh(double complex z)
{
	double complex w;

	w = clog(z + csqrt(z + 1) * csqrt(z - 1));
	return (w);
}
DEF_STD(cacosh);
LDBL_MAYBE_UNUSED_CLONE(cacosh);