1 /* $OpenBSD: s_cacosh.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 /* cacosh 19 * 20 * Complex inverse hyperbolic cosine 21 * 22 * 23 * 24 * SYNOPSIS: 25 * 26 * double complex cacosh(); 27 * double complex z, w; 28 * 29 * w = cacosh (z); 30 * 31 * 32 * 33 * DESCRIPTION: 34 * 35 * acosh z = i acos z . 36 * 37 * ACCURACY: 38 * 39 * Relative error: 40 * arithmetic domain # trials peak rms 41 * IEEE -10,+10 30000 1.6e-14 2.1e-15 42 * 43 */ 44 45 #include <complex.h> 46 #include <float.h> 47 #include <math.h> 48 49 double complex 50 cacosh(double complex z) 51 { 52 double complex w; 53 double rx, ry; 54 55 w = cacos (z); 56 rx = creal (w); 57 ry = cimag (w); 58 if (isnan(rx) && isnan(ry)) 59 return (CMPLX(ry, rx)); 60 /* cacosh(NaN + I*+-Inf) = +Inf + I*NaN */ 61 /* cacosh(+-Inf + I*NaN) = +Inf + I*NaN */ 62 if (isnan(rx)) 63 return (CMPLX(fabs(ry), rx)); 64 /* cacosh(0 + I*NaN) = NaN + I*NaN */ 65 if (isnan(ry)) 66 return (CMPLX(ry, ry)); 67 return (CMPLX(fabs(ry), copysign(rx, cimag(z)))); 68 } 69 70 #if LDBL_MANT_DIG == DBL_MANT_DIG 71 __strong_alias(cacoshl, cacosh); 72 #endif /* LDBL_MANT_DIG == DBL_MANT_DIG */ 73