1 | #include "erfa.h"
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2 |
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3 | void eraAper13(double ut11, double ut12, eraASTROM *astrom)
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4 | /*
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5 | ** - - - - - - - - - -
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6 | ** e r a A p e r 1 3
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7 | ** - - - - - - - - - -
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8 | **
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9 | ** In the star-independent astrometry parameters, update only the
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10 | ** Earth rotation angle. The caller provides UT1, (n.b. not UTC).
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11 | **
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12 | ** Given:
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13 | ** ut11 double UT1 as a 2-part...
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14 | ** ut12 double ...Julian Date (Note 1)
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15 | ** astrom eraASTROM* star-independent astrometry parameters:
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16 | ** pmt double not used
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17 | ** eb double[3] not used
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18 | ** eh double[3] not used
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19 | ** em double not used
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20 | ** v double[3] not used
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21 | ** bm1 double not used
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22 | ** bpn double[3][3] not used
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23 | ** along double longitude + s' (radians)
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24 | ** xpl double not used
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25 | ** ypl double not used
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26 | ** sphi double not used
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27 | ** cphi double not used
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28 | ** diurab double not used
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29 | ** eral double not used
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30 | ** refa double not used
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31 | ** refb double not used
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32 | **
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33 | ** Returned:
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34 | ** astrom eraASTROM* star-independent astrometry parameters:
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35 | ** pmt double unchanged
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36 | ** eb double[3] unchanged
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37 | ** eh double[3] unchanged
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38 | ** em double unchanged
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39 | ** v double[3] unchanged
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40 | ** bm1 double unchanged
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41 | ** bpn double[3][3] unchanged
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42 | ** along double unchanged
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43 | ** xpl double unchanged
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44 | ** ypl double unchanged
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45 | ** sphi double unchanged
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46 | ** cphi double unchanged
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47 | ** diurab double unchanged
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48 | ** eral double "local" Earth rotation angle (radians)
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49 | ** refa double unchanged
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50 | ** refb double unchanged
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51 | **
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52 | ** Notes:
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53 | **
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54 | ** 1) The UT1 date (n.b. not UTC) ut11+ut12 is a Julian Date,
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55 | ** apportioned in any convenient way between the arguments ut11 and
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56 | ** ut12. For example, JD(UT1)=2450123.7 could be expressed in any
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57 | ** of these ways, among others:
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58 | **
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59 | ** ut11 ut12
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60 | **
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61 | ** 2450123.7 0.0 (JD method)
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62 | ** 2451545.0 -1421.3 (J2000 method)
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63 | ** 2400000.5 50123.2 (MJD method)
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64 | ** 2450123.5 0.2 (date & time method)
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65 | **
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66 | ** The JD method is the most natural and convenient to use in cases
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67 | ** where the loss of several decimal digits of resolution is
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68 | ** acceptable. The J2000 and MJD methods are good compromises
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69 | ** between resolution and convenience. The date & time method is
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70 | ** best matched to the algorithm used: maximum precision is
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71 | ** delivered when the ut11 argument is for 0hrs UT1 on the day in
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72 | ** question and the ut12 argument lies in the range 0 to 1, or vice
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73 | ** versa.
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74 | **
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75 | ** 2) If the caller wishes to provide the Earth rotation angle itself,
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76 | ** the function eraAper can be used instead. One use of this
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77 | ** technique is to substitute Greenwich apparent sidereal time and
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78 | ** thereby to support equinox based transformations directly.
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79 | **
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80 | ** 3) This is one of several functions that inserts into the astrom
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81 | ** structure star-independent parameters needed for the chain of
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82 | ** astrometric transformations ICRS <-> GCRS <-> CIRS <-> observed.
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83 | **
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84 | ** The various functions support different classes of observer and
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85 | ** portions of the transformation chain:
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86 | **
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87 | ** functions observer transformation
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88 | **
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89 | ** eraApcg eraApcg13 geocentric ICRS <-> GCRS
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90 | ** eraApci eraApci13 terrestrial ICRS <-> CIRS
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91 | ** eraApco eraApco13 terrestrial ICRS <-> observed
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92 | ** eraApcs eraApcs13 space ICRS <-> GCRS
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93 | ** eraAper eraAper13 terrestrial update Earth rotation
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94 | ** eraApio eraApio13 terrestrial CIRS <-> observed
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95 | **
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96 | ** Those with names ending in "13" use contemporary ERFA models to
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97 | ** compute the various ephemerides. The others accept ephemerides
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98 | ** supplied by the caller.
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99 | **
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100 | ** The transformation from ICRS to GCRS covers space motion,
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101 | ** parallax, light deflection, and aberration. From GCRS to CIRS
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102 | ** comprises frame bias and precession-nutation. From CIRS to
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103 | ** observed takes account of Earth rotation, polar motion, diurnal
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104 | ** aberration and parallax (unless subsumed into the ICRS <-> GCRS
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105 | ** transformation), and atmospheric refraction.
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106 | **
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107 | ** Called:
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108 | ** eraAper astrometry parameters: update ERA
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109 | ** eraEra00 Earth rotation angle, IAU 2000
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110 | **
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111 | ** Copyright (C) 2013-2017, NumFOCUS Foundation.
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112 | ** Derived, with permission, from the SOFA library. See notes at end of file.
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113 | */
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114 | {
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115 | eraAper(eraEra00(ut11,ut12), astrom);
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116 |
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117 | /* Finished. */
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118 |
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119 | }
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120 | /*----------------------------------------------------------------------
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121 | **
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122 | **
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123 | ** Copyright (C) 2013-2017, NumFOCUS Foundation.
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124 | ** All rights reserved.
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125 | **
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126 | ** This library is derived, with permission, from the International
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127 | ** Astronomical Union's "Standards of Fundamental Astronomy" library,
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128 | ** available from http://www.iausofa.org.
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129 | **
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130 | ** The ERFA version is intended to retain identical functionality to
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131 | ** the SOFA library, but made distinct through different function and
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132 | ** file names, as set out in the SOFA license conditions. The SOFA
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133 | ** original has a role as a reference standard for the IAU and IERS,
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134 | ** and consequently redistribution is permitted only in its unaltered
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135 | ** state. The ERFA version is not subject to this restriction and
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136 | ** therefore can be included in distributions which do not support the
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137 | ** concept of "read only" software.
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138 | **
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139 | ** Although the intent is to replicate the SOFA API (other than
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140 | ** replacement of prefix names) and results (with the exception of
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141 | ** bugs; any that are discovered will be fixed), SOFA is not
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142 | ** responsible for any errors found in this version of the library.
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143 | **
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144 | ** If you wish to acknowledge the SOFA heritage, please acknowledge
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145 | ** that you are using a library derived from SOFA, rather than SOFA
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146 | ** itself.
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147 | **
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148 | **
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149 | ** TERMS AND CONDITIONS
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150 | **
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151 | ** Redistribution and use in source and binary forms, with or without
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152 | ** modification, are permitted provided that the following conditions
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153 | ** are met:
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154 | **
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155 | ** 1 Redistributions of source code must retain the above copyright
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156 | ** notice, this list of conditions and the following disclaimer.
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157 | **
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158 | ** 2 Redistributions in binary form must reproduce the above copyright
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159 | ** notice, this list of conditions and the following disclaimer in
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160 | ** the documentation and/or other materials provided with the
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161 | ** distribution.
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162 | **
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163 | ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
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164 | ** the International Astronomical Union nor the names of its
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165 | ** contributors may be used to endorse or promote products derived
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166 | ** from this software without specific prior written permission.
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167 | **
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168 | ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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169 | ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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170 | ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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171 | ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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172 | ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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173 | ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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174 | ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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175 | ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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176 | ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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177 | ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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178 | ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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179 | ** POSSIBILITY OF SUCH DAMAGE.
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180 | **
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181 | */
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