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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libm/src/s_csqrtf.c	Lines:	0	35	0.0 %
Date:	2017-11-13	Branches:	0	14	0.0 %


/*	$OpenBSD: s_csqrtf.c,v 1.4 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.
 */

/*							csqrtf()
 *
 *	Complex square root
 *
 *
 *
 * SYNOPSIS:
 *
 * float complex csqrtf();
 * float complex z, w;
 *
 * w = csqrtf( z );
 *
 *
 *
 * DESCRIPTION:
 *
 *
 * If z = x + iy,  r = |z|, then
 *
 *                       1/2
 * Re w  =  [ (r + x)/2 ]   ,
 *
 *                       1/2
 * Im w  =  [ (r - x)/2 ]   .
 *
 * Cancellation error in r-x or r+x is avoided by using the
 * identity  2 Re w Im w  =  y.
 *
 * Note that -w is also a square root of z.  The root chosen
 * is always in the right half plane and Im w has the same sign as y.
 *
 *
 *
 * ACCURACY:
 *
 *
 *                      Relative error:
 * arithmetic   domain     # trials      peak         rms
 *    IEEE      -10,+10    1,000,000    1.8e-7       3.5e-8
 *
 */

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

float complex
csqrtf(float complex z)
{
	float complex w;
	float x, y, r, t, scale;

	x = crealf(z);
	y = cimagf(z);

	if(y == 0.0f) {
		if (x < 0.0f) {
			w = 0.0f + copysign(sqrtf(-x), y) * I;
			return (w);
		}
		else if (x == 0.0f) {
			return (0.0f + y * I);
		}
		else {
			w = sqrtf(x) + y * I;
			return (w);
		}
	}

	if (x == 0.0f) {
		r = fabsf(y);
		r = sqrtf(0.5f*r);
		if(y > 0)
			w = r + r * I;
		else
			w = r - r * I;
		return (w);
	}

	/* Rescale to avoid internal overflow or underflow.  */
	if ((fabsf(x) > 4.0f) || (fabsf(y) > 4.0f)) {
		x *= 0.25f;
		y *= 0.25f;
		scale = 2.0f;
	}
	else {
		x *= 6.7108864e7f; /* 2^26 */
		y *= 6.7108864e7f;
		scale = 1.220703125e-4f; /* 2^-13 */
#if 0
		x *= 4.0f;
		y *= 4.0f;
		scale = 0.5f;
#endif
	}
	w = x + y * I;
	r = cabsf(w);
	if (x > 0) {
		t = sqrtf( 0.5f * r + 0.5f * x );
		r = scale * fabsf((0.5f * y) / t);
		t *= scale;
	}
	else {
		r = sqrtf(0.5f * r - 0.5f * x);
		t = scale * fabsf((0.5f * y) / r);
		r *= scale;
	}

	if (y < 0)
		w = t - r * I;
	else
		w = t + r * I;
	return (w);
}
DEF_STD(csqrtf);


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: s_csqrtf.c,v 1.4 2016/09/12 19:47:02 guenther Exp $ */
2			/*
3			* Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
4			*
5			* Permission to use, copy, modify, and distribute this software for any
6			* purpose with or without fee is hereby granted, provided that the above
7			* copyright notice and this permission notice appear in all copies.
8			*
9			* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10			* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11			* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12			* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13			* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14			* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15			* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16			*/
17
18			/* csqrtf()
19			*
20			* Complex square root
21			*
22			*
23			*
24			* SYNOPSIS:
25			*
26			* float complex csqrtf();
27			* float complex z, w;
28			*
29			* w = csqrtf( z );
30			*
31			*
32			*
33			* DESCRIPTION:
34			*
35			*
36			* If z = x + iy, r = \|z\|, then
37			*
38			* 1/2
39			* Re w = [ (r + x)/2 ] ,
40			*
41			* 1/2
42			* Im w = [ (r - x)/2 ] .
43			*
44			* Cancellation error in r-x or r+x is avoided by using the
45			* identity 2 Re w Im w = y.
46			*
47			* Note that -w is also a square root of z. The root chosen
48			* is always in the right half plane and Im w has the same sign as y.
49			*
50			*
51			*
52			* ACCURACY:
53			*
54			*
55			* Relative error:
56			* arithmetic domain # trials peak rms
57			* IEEE -10,+10 1,000,000 1.8e-7 3.5e-8
58			*
59			*/
60
61			#include <complex.h>
62			#include <math.h>
63
64			float complex
65			csqrtf(float complex z)
66			{
67			float complex w;
68			float x, y, r, t, scale;
69
70			x = crealf(z);
71			y = cimagf(z);
72
73			if(y == 0.0f) {
74			if (x < 0.0f) {
75			w = 0.0f + copysign(sqrtf(-x), y) * I;
76			return (w);
77			}
78			else if (x == 0.0f) {
79			return (0.0f + y * I);
80			}
81			else {
82			w = sqrtf(x) + y * I;
83			return (w);
84			}
85			}
86
87			if (x == 0.0f) {
88			r = fabsf(y);
89			r = sqrtf(0.5f*r);
90			if(y > 0)
91			w = r + r * I;
92			else
93			w = r - r * I;
94			return (w);
95			}
96
97			/* Rescale to avoid internal overflow or underflow. */
98			if ((fabsf(x) > 4.0f) \|\| (fabsf(y) > 4.0f)) {
99			x *= 0.25f;
100			y *= 0.25f;
101			scale = 2.0f;
102			}
103			else {
104			x = 6.7108864e7f; / 2^26 */
105			y *= 6.7108864e7f;
106			scale = 1.220703125e-4f; /* 2^-13 */
107			#if 0
108			x *= 4.0f;
109			y *= 4.0f;
110			scale = 0.5f;
111			#endif
112			}
113			w = x + y * I;
114			r = cabsf(w);
115			if (x > 0) {
116			t = sqrtf( 0.5f * r + 0.5f * x );
117			r = scale * fabsf((0.5f * y) / t);
118			t *= scale;
119			}
120			else {
121			r = sqrtf(0.5f * r - 0.5f * x);
122			t = scale * fabsf((0.5f * y) / r);
123			r *= scale;
124			}
125
126			if (y < 0)
127			w = t - r * I;
128			else
129			w = t + r * I;
130			return (w);
131			}
132			DEF_STD(csqrtf);