1 | /* $NetBSD: cpow.c,v 1.1 2007/08/20 16:01:35 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 | <<cpow>>, <<cpowf>>---complex power |
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38 | |
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39 | INDEX |
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40 | cpow |
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41 | INDEX |
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42 | cpowf |
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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 cpow(double complex <[x]>, double complex <[y]>); |
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47 | float complex cpowf(float complex <[x]>, float complex <[y]>); |
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48 | |
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49 | |
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50 | DESCRIPTION |
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51 | @ifnottex |
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52 | The cpow functions compute the complex power function x^y |
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53 | power, with a branch cut for the first parameter along the |
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54 | negative real axis. |
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55 | @end ifnottex |
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56 | @tex |
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57 | The cpow functions compute the complex power function $x^y$ |
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58 | power, with a branch cut for the first parameter along the |
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59 | negative real axis. |
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60 | @end tex |
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61 | |
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62 | <<cpowf>> is identical to <<cpow>>, except that it performs |
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63 | its calculations on <<floats complex>>. |
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64 | |
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65 | RETURNS |
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66 | The cpow functions return the complex power function value. |
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67 | |
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68 | PORTABILITY |
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69 | <<cpow>> and <<cpowf>> are ISO C99 |
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70 | |
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71 | QUICKREF |
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72 | <<cpow>> and <<cpowf>> are ISO C99 |
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73 | |
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74 | */ |
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75 | |
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76 | |
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77 | #include <complex.h> |
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78 | #include <math.h> |
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79 | |
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80 | double complex |
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81 | cpow(double complex a, double complex z) |
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82 | { |
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83 | double complex w; |
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84 | double x, y, r, theta, absa, arga; |
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85 | |
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86 | x = creal(z); |
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87 | y = cimag(z); |
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88 | absa = cabs(a); |
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89 | if (absa == 0.0) { |
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90 | return (0.0 + 0.0 * I); |
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91 | } |
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92 | arga = carg(a); |
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93 | r = pow(absa, x); |
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94 | theta = x * arga; |
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95 | if (y != 0.0) { |
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96 | r = r * exp(-y * arga); |
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97 | theta = theta + y * log(absa); |
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98 | } |
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99 | w = r * cos(theta) + (r * sin(theta)) * I; |
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100 | return w; |
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101 | } |
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