| 1 | #include "erfa.h"
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| 2 |
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| 3 | void eraPn00(double date1, double date2, double dpsi, double deps,
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| 4 | double *epsa,
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| 5 | double rb[3][3], double rp[3][3], double rbp[3][3],
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| 6 | double rn[3][3], double rbpn[3][3])
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| 7 | /*
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| 8 | ** - - - - - - - -
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| 9 | ** e r a P n 0 0
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| 10 | ** - - - - - - - -
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| 11 | **
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| 12 | ** Precession-nutation, IAU 2000 model: a multi-purpose function,
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| 13 | ** supporting classical (equinox-based) use directly and CIO-based
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| 14 | ** use indirectly.
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| 15 | **
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| 16 | ** Given:
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| 17 | ** date1,date2 double TT as a 2-part Julian Date (Note 1)
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| 18 | ** dpsi,deps double nutation (Note 2)
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| 19 | **
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| 20 | ** Returned:
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| 21 | ** epsa double mean obliquity (Note 3)
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| 22 | ** rb double[3][3] frame bias matrix (Note 4)
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| 23 | ** rp double[3][3] precession matrix (Note 5)
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| 24 | ** rbp double[3][3] bias-precession matrix (Note 6)
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| 25 | ** rn double[3][3] nutation matrix (Note 7)
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| 26 | ** rbpn double[3][3] GCRS-to-true matrix (Note 8)
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| 27 | **
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| 28 | ** Notes:
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| 29 | **
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| 30 | ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
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| 31 | ** convenient way between the two arguments. For example,
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| 32 | ** JD(TT)=2450123.7 could be expressed in any of these ways,
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| 33 | ** among others:
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| 34 | **
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| 35 | ** date1 date2
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| 36 | **
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| 37 | ** 2450123.7 0.0 (JD method)
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| 38 | ** 2451545.0 -1421.3 (J2000 method)
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| 39 | ** 2400000.5 50123.2 (MJD method)
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| 40 | ** 2450123.5 0.2 (date & time method)
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| 41 | **
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| 42 | ** The JD method is the most natural and convenient to use in
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| 43 | ** cases where the loss of several decimal digits of resolution
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| 44 | ** is acceptable. The J2000 method is best matched to the way
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| 45 | ** the argument is handled internally and will deliver the
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| 46 | ** optimum resolution. The MJD method and the date & time methods
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| 47 | ** are both good compromises between resolution and convenience.
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| 48 | **
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| 49 | ** 2) The caller is responsible for providing the nutation components;
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| 50 | ** they are in longitude and obliquity, in radians and are with
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| 51 | ** respect to the equinox and ecliptic of date. For high-accuracy
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| 52 | ** applications, free core nutation should be included as well as
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| 53 | ** any other relevant corrections to the position of the CIP.
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| 54 | **
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| 55 | ** 3) The returned mean obliquity is consistent with the IAU 2000
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| 56 | ** precession-nutation models.
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| 57 | **
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| 58 | ** 4) The matrix rb transforms vectors from GCRS to J2000.0 mean
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| 59 | ** equator and equinox by applying frame bias.
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| 60 | **
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| 61 | ** 5) The matrix rp transforms vectors from J2000.0 mean equator and
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| 62 | ** equinox to mean equator and equinox of date by applying
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| 63 | ** precession.
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| 64 | **
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| 65 | ** 6) The matrix rbp transforms vectors from GCRS to mean equator and
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| 66 | ** equinox of date by applying frame bias then precession. It is
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| 67 | ** the product rp x rb.
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| 68 | **
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| 69 | ** 7) The matrix rn transforms vectors from mean equator and equinox of
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| 70 | ** date to true equator and equinox of date by applying the nutation
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| 71 | ** (luni-solar + planetary).
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| 72 | **
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| 73 | ** 8) The matrix rbpn transforms vectors from GCRS to true equator and
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| 74 | ** equinox of date. It is the product rn x rbp, applying frame
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| 75 | ** bias, precession and nutation in that order.
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| 76 | **
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| 77 | ** 9) It is permissible to re-use the same array in the returned
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| 78 | ** arguments. The arrays are filled in the order given.
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| 79 | **
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| 80 | ** Called:
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| 81 | ** eraPr00 IAU 2000 precession adjustments
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| 82 | ** eraObl80 mean obliquity, IAU 1980
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| 83 | ** eraBp00 frame bias and precession matrices, IAU 2000
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| 84 | ** eraCr copy r-matrix
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| 85 | ** eraNumat form nutation matrix
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| 86 | ** eraRxr product of two r-matrices
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| 87 | **
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| 88 | ** Reference:
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| 89 | **
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| 90 | ** Capitaine, N., Chapront, J., Lambert, S. and Wallace, P.,
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| 91 | ** "Expressions for the Celestial Intermediate Pole and Celestial
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| 92 | ** Ephemeris Origin consistent with the IAU 2000A precession-
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| 93 | ** nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
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| 94 | **
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| 95 | ** n.b. The celestial ephemeris origin (CEO) was renamed "celestial
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| 96 | ** intermediate origin" (CIO) by IAU 2006 Resolution 2.
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| 97 | **
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| 98 | ** Copyright (C) 2013-2016, NumFOCUS Foundation.
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| 99 | ** Derived, with permission, from the SOFA library. See notes at end of file.
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| 100 | */
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| 101 | {
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| 102 | double dpsipr, depspr, rbpw[3][3], rnw[3][3];
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| 103 |
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| 104 |
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| 105 | /* IAU 2000 precession-rate adjustments. */
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| 106 | eraPr00(date1, date2, &dpsipr, &depspr);
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| 107 |
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| 108 | /* Mean obliquity, consistent with IAU 2000 precession-nutation. */
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| 109 | *epsa = eraObl80(date1, date2) + depspr;
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| 110 |
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| 111 | /* Frame bias and precession matrices and their product. */
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| 112 | eraBp00(date1, date2, rb, rp, rbpw);
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| 113 | eraCr(rbpw, rbp);
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| 114 |
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| 115 | /* Nutation matrix. */
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| 116 | eraNumat(*epsa, dpsi, deps, rnw);
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| 117 | eraCr(rnw, rn);
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| 118 |
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| 119 | /* Bias-precession-nutation matrix (classical). */
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| 120 | eraRxr(rnw, rbpw, rbpn);
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| 121 |
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| 122 | return;
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| 123 |
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| 124 | }
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| 125 | /*----------------------------------------------------------------------
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| 126 | **
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| 127 | **
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| 128 | ** Copyright (C) 2013-2016, NumFOCUS Foundation.
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| 129 | ** All rights reserved.
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| 130 | **
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| 131 | ** This library is derived, with permission, from the International
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| 132 | ** Astronomical Union's "Standards of Fundamental Astronomy" library,
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| 133 | ** available from http://www.iausofa.org.
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| 134 | **
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| 135 | ** The ERFA version is intended to retain identical functionality to
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| 136 | ** the SOFA library, but made distinct through different function and
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| 137 | ** file names, as set out in the SOFA license conditions. The SOFA
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| 138 | ** original has a role as a reference standard for the IAU and IERS,
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| 139 | ** and consequently redistribution is permitted only in its unaltered
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| 140 | ** state. The ERFA version is not subject to this restriction and
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| 141 | ** therefore can be included in distributions which do not support the
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| 142 | ** concept of "read only" software.
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| 143 | **
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| 144 | ** Although the intent is to replicate the SOFA API (other than
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| 145 | ** replacement of prefix names) and results (with the exception of
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| 146 | ** bugs; any that are discovered will be fixed), SOFA is not
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| 147 | ** responsible for any errors found in this version of the library.
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| 148 | **
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| 149 | ** If you wish to acknowledge the SOFA heritage, please acknowledge
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| 150 | ** that you are using a library derived from SOFA, rather than SOFA
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| 151 | ** itself.
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| 152 | **
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| 153 | **
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| 154 | ** TERMS AND CONDITIONS
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| 155 | **
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| 156 | ** Redistribution and use in source and binary forms, with or without
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| 157 | ** modification, are permitted provided that the following conditions
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| 158 | ** are met:
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| 159 | **
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| 160 | ** 1 Redistributions of source code must retain the above copyright
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| 161 | ** notice, this list of conditions and the following disclaimer.
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| 162 | **
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| 163 | ** 2 Redistributions in binary form must reproduce the above copyright
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| 164 | ** notice, this list of conditions and the following disclaimer in
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| 165 | ** the documentation and/or other materials provided with the
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| 166 | ** distribution.
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| 167 | **
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| 168 | ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
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| 169 | ** the International Astronomical Union nor the names of its
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| 170 | ** contributors may be used to endorse or promote products derived
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| 171 | ** from this software without specific prior written permission.
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| 172 | **
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| 173 | ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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| 174 | ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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| 175 | ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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| 176 | ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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| 177 | ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 178 | ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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| 179 | ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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| 180 | ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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| 181 | ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 182 | ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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| 183 | ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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| 184 | ** POSSIBILITY OF SUCH DAMAGE.
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| 185 | **
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| 186 | */
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