1 | /* $NetBSD: cacosh.c,v 1.2 2009/08/03 19:41:32 drochner 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 | * imported and modified include for newlib 2010/10/03 |
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32 | * Marco Atzeri <marco_atzeri@yahoo.it> |
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33 | */ |
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34 | |
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35 | /* |
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36 | FUNCTION |
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37 | <<cacosh>>, <<cacoshf>>---complex arc hyperbolic cosine |
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38 | |
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39 | INDEX |
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40 | cacosh |
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41 | INDEX |
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42 | cacoshf |
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43 | |
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44 | SYNOPSIS |
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45 | #include <complex.h> |
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46 | double complex cacosh(double complex <[z]>); |
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47 | float complex cacoshf(float complex <[z]>); |
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48 | |
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49 | |
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50 | DESCRIPTION |
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51 | These functions compute the complex arc hyperbolic cosine of <[z]>, |
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52 | with a branch cut at values less than 1 along the real axis. |
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53 | |
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54 | <<cacoshf>> is identical to <<cacosh>>, except that it performs |
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55 | its calculations on <<floats complex>>. |
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56 | |
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57 | RETURNS |
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58 | @ifnottex |
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59 | These functions return the complex arc hyperbolic cosine value, |
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60 | in the range of a half-strip of non-negative values along the |
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61 | real axis and in the interval [-i * pi, +i * pi] along the |
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62 | imaginary axis. |
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63 | @end ifnottex |
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64 | @tex |
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65 | These functions return the complex arc hyperbolic cosine value, |
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66 | in the range of a half-strip of non-negative values along the |
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67 | real axis and in the interval [$-i\pi$, $+i\pi$] along the |
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68 | imaginary axis. |
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69 | @end tex |
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70 | |
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71 | PORTABILITY |
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72 | <<cacosh>> and <<cacoshf>> are ISO C99 |
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73 | |
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74 | QUICKREF |
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75 | <<cacosh>> and <<cacoshf>> are ISO C99 |
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76 | |
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77 | */ |
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78 | |
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79 | |
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80 | #include <complex.h> |
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81 | |
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82 | double complex |
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83 | cacosh(double complex z) |
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84 | { |
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85 | double complex w; |
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86 | |
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87 | #if 0 /* does not give the principal value */ |
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88 | w = I * cacos(z); |
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89 | #else |
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90 | w = clog(z + csqrt(z + 1) * csqrt(z - 1)); |
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91 | #endif |
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92 | return w; |
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93 | } |
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