1 /* $OpenBSD: s_cacos.c,v 1.2 2011/07/08 19:25:31 martynas 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 /* LINTLIBRARY */ 19 20 /* cacos() 21 * 22 * Complex circular arc cosine 23 * 24 * 25 * 26 * SYNOPSIS: 27 * 28 * double complex cacos(); 29 * double complex z, w; 30 * 31 * w = cacos (z); 32 * 33 * 34 * 35 * DESCRIPTION: 36 * 37 * 38 * w = arccos z = PI/2 - arcsin z. 39 * 40 * 41 * 42 * 43 * ACCURACY: 44 * 45 * Relative error: 46 * arithmetic domain # trials peak rms 47 * DEC -10,+10 5200 1.6e-15 2.8e-16 48 * IEEE -10,+10 30000 1.8e-14 2.2e-15 49 */ 50 51 #include <sys/cdefs.h> 52 #include <complex.h> 53 #include <float.h> 54 #include <math.h> 55 56 double complex 57 cacos(double complex z) 58 { 59 double complex w; 60 61 w = casin (z); 62 w = (M_PI_2 - creal (w)) - cimag (w) * I; 63 return (w); 64 } 65 66 #if LDBL_MANT_DIG == 53 67 #ifdef lint 68 /* PROTOLIB1 */ 69 long double complex cacosl(long double complex); 70 #else /* lint */ 71 __weak_alias(cacosl, cacos); 72 #endif /* lint */ 73 #endif /* LDBL_MANT_DIG == 53 */ 74