1 /* $OpenBSD: s_cacos.c,v 1.6 2013/07/03 04:46:36 espie 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 /* cacos() 19 * 20 * Complex circular arc cosine 21 * 22 * 23 * 24 * SYNOPSIS: 25 * 26 * double complex cacos(); 27 * double complex z, w; 28 * 29 * w = cacos (z); 30 * 31 * 32 * 33 * DESCRIPTION: 34 * 35 * 36 * w = arccos z = PI/2 - arcsin z. 37 * 38 * 39 * 40 * 41 * ACCURACY: 42 * 43 * Relative error: 44 * arithmetic domain # trials peak rms 45 * DEC -10,+10 5200 1.6e-15 2.8e-16 46 * IEEE -10,+10 30000 1.8e-14 2.2e-15 47 */ 48 49 #include <complex.h> 50 #include <float.h> 51 #include <math.h> 52 53 double complex 54 cacos(double complex z) 55 { 56 double complex w; 57 58 w = casin (z); 59 w = (M_PI_2 - creal (w)) - cimag (w) * I; 60 return (w); 61 } 62 63 #if LDBL_MANT_DIG == DBL_MANT_DIG 64 __strong_alias(cacosl, cacos); 65 #endif /* LDBL_MANT_DIG == DBL_MANT_DIG */ 66