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/* $NetBSD: clog.c,v 1.1 2007/08/20 16:01:35 drochner Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software written by Stephen L. Moshier.
* It is redistributed by the NetBSD Foundation by permission of the author.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* imported and modified include for newlib 2010/10/03
* Marco Atzeri <marco_atzeri@yahoo.it>
*/
/*
FUNCTION
<<clog>>, <<clogf>>---complex base-e logarithm
INDEX
clog
INDEX
clogf
ANSI_SYNOPSIS
#include <complex.h>
double complex clog(double complex <[z]>);
float complex clogf(float complex <[z]>);
DESCRIPTION
These functions compute the complex natural (base-<[e]>) logarithm
of <[z]>, with a branch cut along the negative real axis.
<<clogf>> is identical to <<clog>>, except that it performs
its calculations on <<floats complex>>.
RETURNS
@ifnottex
The clog functions return the complex natural logarithm value, in
the range of a strip mathematically unbounded along the real axis
and in the interval [-i*pi , +i*pi] along the imaginary axis.
@end ifnottex
@tex
The clog functions return the complex natural logarithm value, in
the range of a strip mathematically unbounded along the real axis
and in the interval [$-i\pi$, $+i\pi$] along the imaginary axis.
@end tex
PORTABILITY
<<clog>> and <<clogf>> are ISO C99
QUICKREF
<<clog>> and <<clogf>> are ISO C99
*/
#include <complex.h>
#include <math.h>
double complex
clog(double complex z)
{
double complex w;
double p, rr;
rr = cabs(z);
p = log(rr);
rr = atan2(cimag(z), creal(z));
w = p + rr * I;
return w;
}
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