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    /*	$OpenBSD: s_cacos.c,v 1.7 2016/09/12 19:47:02 guenther Exp $	*/  | 
    
    
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    /*  | 
    
    
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     * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>  | 
    
    
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     *  | 
    
    
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     * Permission to use, copy, modify, and distribute this software for any  | 
    
    
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     * purpose with or without fee is hereby granted, provided that the above  | 
    
    
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     * copyright notice and this permission notice appear in all copies.  | 
    
    
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     *  | 
    
    
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     * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES  | 
    
    
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     * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF  | 
    
    
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     * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  | 
    
    
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     * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES  | 
    
    
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     * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN  | 
    
    
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     * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  | 
    
    
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     * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  | 
    
    
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     */  | 
    
    
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    /*							cacos()  | 
    
    
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     *  | 
    
    
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     *	Complex circular arc cosine  | 
    
    
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     *  | 
    
    
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     * SYNOPSIS:  | 
    
    
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     *  | 
    
    
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     * double complex cacos();  | 
    
    
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     * double complex z, w;  | 
    
    
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     *  | 
    
    
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     * w = cacos (z);  | 
    
    
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     *  | 
    
    
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     *  | 
    
    
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     *  | 
    
    
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     * DESCRIPTION:  | 
    
    
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     *  | 
    
    
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     *  | 
    
    
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     * w = arccos z  =  PI/2 - arcsin z.  | 
    
    
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     *  | 
    
    
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     *  | 
    
    
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     *  | 
    
    
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     *  | 
    
    
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     * ACCURACY:  | 
    
    
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     *  | 
    
    
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     *                      Relative error:  | 
    
    
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     * arithmetic   domain     # trials      peak         rms  | 
    
    
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     *    DEC       -10,+10      5200      1.6e-15      2.8e-16  | 
    
    
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     *    IEEE      -10,+10     30000      1.8e-14      2.2e-15  | 
    
    
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     */  | 
    
    
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    #include <complex.h>  | 
    
    
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    #include <float.h>  | 
    
    
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    #include <math.h>  | 
    
    
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    double complex  | 
    
    
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    cacos(double complex z)  | 
    
    
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    { | 
    
    
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    	double complex w;  | 
    
    
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    	w = casin (z);  | 
    
    
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    	w = (M_PI_2 - creal (w)) - cimag (w) * I;  | 
    
    
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    	return (w);  | 
    
    
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    }  | 
    
    
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    DEF_STD(cacos);  | 
    
    
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    LDBL_MAYBE_UNUSED_CLONE(cacos);  |