1 /* $NetBSD: catan.c,v 1.1 2007/08/20 16:01:32 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 #include "cephes_subr.h" 36 37 #ifdef __weak_alias 38 __weak_alias(catan, _catan) 39 #endif 40 41 #define MAXNUM 1.0e308 42 43 double complex 44 catan(double complex z) 45 { 46 double complex w; 47 double a, t, x, x2, y; 48 49 x = creal(z); 50 y = cimag(z); 51 52 if ((x == 0.0) && (y > 1.0)) 53 goto ovrf; 54 55 x2 = x * x; 56 a = 1.0 - x2 - (y * y); 57 if (a == 0.0) 58 goto ovrf; 59 60 t = 0.5 * atan2(2.0 * x, a); 61 w = _redupi(t); 62 63 t = y - 1.0; 64 a = x2 + (t * t); 65 if (a == 0.0) 66 goto ovrf; 67 68 t = y + 1.0; 69 a = (x2 + (t * t))/a; 70 w = w + (0.25 * log(a)) * I; 71 return w; 72 73 ovrf: 74 #if 0 75 mtherr ("catan", OVERFLOW); 76 #endif 77 w = MAXNUM + MAXNUM * I; 78 return w; 79 } 80