| 1 | /* $NetBSD: catanl.c,v 1.1 2014/10/10 00:48:18 christos Exp $ */ |
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| 2 | |
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| 3 | /*- |
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| 4 | * Copyright (c) 2007 The NetBSD Foundation, Inc. |
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| 5 | * All rights reserved. |
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| 6 | * |
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| 7 | * This code is derived from software written by Stephen L. Moshier. |
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| 8 | * It is redistributed by the NetBSD Foundation by permission of the author. |
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| 9 | * |
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| 10 | * Redistribution and use in source and binary forms, with or without |
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| 11 | * modification, are permitted provided that the following conditions |
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| 12 | * are met: |
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| 13 | * 1. Redistributions of source code must retain the above copyright |
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| 14 | * notice, this list of conditions and the following disclaimer. |
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 16 | * notice, this list of conditions and the following disclaimer in the |
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| 17 | * documentation and/or other materials provided with the distribution. |
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| 18 | * |
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| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
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| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
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| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
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| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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| 29 | * POSSIBILITY OF SUCH DAMAGE. |
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| 30 | */ |
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| 31 | |
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| 32 | #include <complex.h> |
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| 33 | #include <math.h> |
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| 34 | #include "cephes_subrl.h" |
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| 35 | |
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| 36 | #ifdef __weak_alias |
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| 37 | __weak_alias(catanl, _catanl) |
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| 38 | #endif |
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| 39 | |
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| 40 | long double complex |
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| 41 | catanl(long double complex z) |
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| 42 | { |
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| 43 | long double complex w; |
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| 44 | long double a, t, x, x2, y; |
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| 45 | |
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| 46 | x = creall(z); |
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| 47 | y = cimagl(z); |
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| 48 | |
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| 49 | if ((x == 0.0L) && (y > 1.0L)) |
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| 50 | goto ovrf; |
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| 51 | |
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| 52 | x2 = x * x; |
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| 53 | a = 1.0L - x2 - (y * y); |
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| 54 | if (a == 0.0) |
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| 55 | goto ovrf; |
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| 56 | |
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| 57 | t = 0.5L * atan2l(2.0L * x, a); |
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| 58 | w = _redupil(t); |
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| 59 | |
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| 60 | t = y - 1.0L; |
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| 61 | a = x2 + (t * t); |
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| 62 | if (a == 0.0L) |
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| 63 | goto ovrf; |
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| 64 | |
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| 65 | t = y + 1.0L; |
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| 66 | a = (x2 + (t * t))/a; |
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| 67 | w = w + (0.25L * logl(a)) * I; |
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| 68 | return w; |
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| 69 | |
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| 70 | ovrf: |
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| 71 | #if 0 |
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| 72 | mtherr ("catanl", OVERFLOW); |
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| 73 | #endif |
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| 74 | w = HUGE_VALL + HUGE_VALL * I; |
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| 75 | return w; |
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| 76 | } |
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| 77 | |
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