GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libm/src/s_casinf.c Lines: 0 11 0.0 %
Date: 2017-11-13 Branches: 0 4 0.0 %

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/*	$OpenBSD: s_casinf.c,v 1.5 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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/*							casinf()
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 *
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 *	Complex circular arc sine
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 *
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 *
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 *
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 * SYNOPSIS:
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 *
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 * void casinf();
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 * cmplxf z, w;
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 *
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 * casinf( &z, &w );
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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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 * Inverse complex sine:
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 *
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 *                               2
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 * w = -i clog( iz + csqrt( 1 - z ) ).
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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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 *    IEEE      -10,+10     30000       1.1e-5      1.5e-6
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 * Larger relative error can be observed for z near zero.
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 *
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 */
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#include <complex.h>
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#include <math.h>
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float complex
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casinf(float complex z)
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{
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	float complex w;
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	float x, y;
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	static float complex ca, ct, zz, z2;
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	/*
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	float cn, n;
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	static float a, b, s, t, u, v, y2;
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	static cmplxf sum;
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	*/
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	x = crealf(z);
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	y = cimagf(z);
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#if 0
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	if(y == 0.0f) {
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		if(fabsf(x) > 1.0f) {
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			w = (float)M_PI_2 + 0.0f * I;
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			/*mtherr( "casinf", DOMAIN );*/
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		}
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		else {
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			w = asinf (x) + 0.0f * I;
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		}
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		return (w);
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	}
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#endif
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	/* Power series expansion */
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	/*
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	b = cabsf(z);
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	if(b < 0.125) {
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		z2.r = (x - y) * (x + y);
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		z2.i = 2.0 * x * y;
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		cn = 1.0;
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		n = 1.0;
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		ca.r = x;
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		ca.i = y;
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		sum.r = x;
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		sum.i = y;
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		do {
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			ct.r = z2.r * ca.r  -  z2.i * ca.i;
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			ct.i = z2.r * ca.i  +  z2.i * ca.r;
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			ca.r = ct.r;
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			ca.i = ct.i;
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			cn *= n;
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			n += 1.0;
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			cn /= n;
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			n += 1.0;
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			b = cn/n;
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			ct.r *= b;
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			ct.i *= b;
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			sum.r += ct.r;
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			sum.i += ct.i;
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			b = fabsf(ct.r) + fabsf(ct.i);
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		}
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		while(b > MACHEPF);
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		w->r = sum.r;
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		w->i = sum.i;
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		return;
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	}
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	*/
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	ca = x + y * I;
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	ct = ca * I;	/* iz */
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	/* sqrt( 1 - z*z) */
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	/* cmul( &ca, &ca, &zz ) */
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	/*x * x  -  y * y */
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	zz = (x - y) * (x + y) + (2.0f * x * y) * I;
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	zz = 1.0f - crealf(zz) - cimagf(zz) * I;
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	z2 = csqrtf (zz);
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	zz = ct + z2;
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	zz = clogf (zz);
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	/* multiply by 1/i = -i */
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	w = zz * (-1.0f * I);
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	return (w);
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}
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DEF_STD(casinf);