1 | #include "erfa.h"
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2 |
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3 | void eraPvxpv(double a[2][3], double b[2][3], double axb[2][3])
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4 | /*
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5 | ** - - - - - - - - -
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6 | ** e r a P v x p v
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7 | ** - - - - - - - - -
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8 | **
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9 | ** Outer (=vector=cross) product of two pv-vectors.
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10 | **
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11 | ** Given:
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12 | ** a double[2][3] first pv-vector
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13 | ** b double[2][3] second pv-vector
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14 | **
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15 | ** Returned:
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16 | ** axb double[2][3] a x b
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17 | **
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18 | ** Notes:
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19 | **
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20 | ** 1) If the position and velocity components of the two pv-vectors are
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21 | ** ( ap, av ) and ( bp, bv ), the result, a x b, is the pair of
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22 | ** vectors ( ap x bp, ap x bv + av x bp ). The two vectors are the
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23 | ** cross-product of the two p-vectors and its derivative.
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24 | **
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25 | ** 2) It is permissible to re-use the same array for any of the
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26 | ** arguments.
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27 | **
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28 | ** Called:
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29 | ** eraCpv copy pv-vector
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30 | ** eraPxp vector product of two p-vectors
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31 | ** eraPpp p-vector plus p-vector
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32 | **
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33 | ** Copyright (C) 2013-2016, NumFOCUS Foundation.
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34 | ** Derived, with permission, from the SOFA library. See notes at end of file.
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35 | */
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36 | {
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37 | double wa[2][3], wb[2][3], axbd[3], adxb[3];
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38 |
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39 |
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40 | /* Make copies of the inputs. */
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41 | eraCpv(a, wa);
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42 | eraCpv(b, wb);
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43 |
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44 | /* a x b = position part of result. */
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45 | eraPxp(wa[0], wb[0], axb[0]);
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46 |
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47 | /* a x bdot + adot x b = velocity part of result. */
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48 | eraPxp(wa[0], wb[1], axbd);
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49 | eraPxp(wa[1], wb[0], adxb);
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50 | eraPpp(axbd, adxb, axb[1]);
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51 |
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52 | return;
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53 |
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54 | }
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55 | /*----------------------------------------------------------------------
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56 | **
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57 | **
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58 | ** Copyright (C) 2013-2016, NumFOCUS Foundation.
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59 | ** All rights reserved.
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60 | **
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61 | ** This library is derived, with permission, from the International
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62 | ** Astronomical Union's "Standards of Fundamental Astronomy" library,
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63 | ** available from http://www.iausofa.org.
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64 | **
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65 | ** The ERFA version is intended to retain identical functionality to
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66 | ** the SOFA library, but made distinct through different function and
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67 | ** file names, as set out in the SOFA license conditions. The SOFA
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68 | ** original has a role as a reference standard for the IAU and IERS,
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69 | ** and consequently redistribution is permitted only in its unaltered
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70 | ** state. The ERFA version is not subject to this restriction and
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71 | ** therefore can be included in distributions which do not support the
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72 | ** concept of "read only" software.
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73 | **
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74 | ** Although the intent is to replicate the SOFA API (other than
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75 | ** replacement of prefix names) and results (with the exception of
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76 | ** bugs; any that are discovered will be fixed), SOFA is not
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77 | ** responsible for any errors found in this version of the library.
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78 | **
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79 | ** If you wish to acknowledge the SOFA heritage, please acknowledge
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80 | ** that you are using a library derived from SOFA, rather than SOFA
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81 | ** itself.
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82 | **
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83 | **
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84 | ** TERMS AND CONDITIONS
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85 | **
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86 | ** Redistribution and use in source and binary forms, with or without
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87 | ** modification, are permitted provided that the following conditions
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88 | ** are met:
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89 | **
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90 | ** 1 Redistributions of source code must retain the above copyright
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91 | ** notice, this list of conditions and the following disclaimer.
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92 | **
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93 | ** 2 Redistributions in binary form must reproduce the above copyright
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94 | ** notice, this list of conditions and the following disclaimer in
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95 | ** the documentation and/or other materials provided with the
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96 | ** distribution.
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97 | **
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98 | ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
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99 | ** the International Astronomical Union nor the names of its
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100 | ** contributors may be used to endorse or promote products derived
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101 | ** from this software without specific prior written permission.
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102 | **
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103 | ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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104 | ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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105 | ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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106 | ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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107 | ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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108 | ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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109 | ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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110 | ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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111 | ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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112 | ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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113 | ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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114 | ** POSSIBILITY OF SUCH DAMAGE.
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115 | **
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116 | */
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