1 /* $NetBSD: casinf.c,v 1.1 2007/08/20 16:01:31 drochner Exp $ */ 2 3 /*- 4 * Copyright (c) 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software written by Stephen L. Moshier. 8 * It is redistributed by the NetBSD Foundation by permission of the author. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include "../src/namespace.h" 33 #include <complex.h> 34 #include <math.h> 35 36 #ifdef __weak_alias 37 __weak_alias(casinf, _casinf) 38 #endif 39 40 float complex 41 casinf(float complex z) 42 { 43 float complex w; 44 float complex ca, ct, zz, z2; 45 float x, y; 46 47 x = crealf(z); 48 y = cimagf(z); 49 50 #if 0 /* MD: test is incorrect, casin(>1) is defined */ 51 if (y == 0.0f) { 52 if (fabsf(x) > 1.0) { 53 w = M_PI_2 + 0.0f * I; 54 #if 0 55 mtherr ("casin", DOMAIN); 56 #endif 57 } else { 58 w = asinf(x) + 0.0f * I; 59 } 60 return w; 61 } 62 #endif 63 64 /* Power series expansion */ 65 /* 66 b = cabsf(z); 67 if( b < 0.125 ) 68 { 69 z2.r = (x - y) * (x + y); 70 z2.i = 2.0 * x * y; 71 72 cn = 1.0; 73 n = 1.0; 74 ca.r = x; 75 ca.i = y; 76 sum.r = x; 77 sum.i = y; 78 do 79 { 80 ct.r = z2.r * ca.r - z2.i * ca.i; 81 ct.i = z2.r * ca.i + z2.i * ca.r; 82 ca.r = ct.r; 83 ca.i = ct.i; 84 85 cn *= n; 86 n += 1.0; 87 cn /= n; 88 n += 1.0; 89 b = cn/n; 90 91 ct.r *= b; 92 ct.i *= b; 93 sum.r += ct.r; 94 sum.i += ct.i; 95 b = fabsf(ct.r) + fabsf(ct.i); 96 } 97 while( b > MACHEP ); 98 w->r = sum.r; 99 w->i = sum.i; 100 return; 101 } 102 */ 103 104 105 ca = x + y * I; 106 ct = ca * I; 107 /* sqrt( 1 - z*z) */ 108 /* cmul( &ca, &ca, &zz ) */ 109 /*x * x - y * y */ 110 zz = (x - y) * (x + y) + (2.0f * x * y) * I; 111 112 zz = 1.0f - crealf(zz) - cimagf(zz) * I; 113 z2 = csqrtf(zz); 114 115 zz = ct + z2; 116 zz = clogf(zz); 117 /* multiply by 1/i = -i */ 118 w = zz * (-1.0f * I); 119 return w; 120 } 121