Merge commit 'd26ed8388f100a12996c0b92a98040ef2ba7fa8e' as 'ast'

1 files changed, 155 insertions, 0 deletions

diff --git a/ast/erfa/gst00b.c b/ast/erfa/gst00b.c
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+#include "erfa.h"
+
+double eraGst00b(double uta, double utb)
+/*
+**  - - - - - - - - - -
+**   e r a G s t 0 0 b
+**  - - - - - - - - - -
+**
+**  Greenwich apparent sidereal time (consistent with IAU 2000
+**  resolutions but using the truncated nutation model IAU 2000B).
+**
+**  Given:
+**     uta,utb    double    UT1 as a 2-part Julian Date (Notes 1,2)
+**
+**  Returned (function value):
+**                double    Greenwich apparent sidereal time (radians)
+**
+**  Notes:
+**
+**  1) The UT1 date uta+utb is a Julian Date, apportioned in any
+**     convenient way between the argument pair.  For example,
+**     JD=2450123.7 could be expressed in any of these ways, among
+**     others:
+**
+**             uta            utb
+**
+**         2450123.7           0.0       (JD method)
+**         2451545.0       -1421.3       (J2000 method)
+**         2400000.5       50123.2       (MJD method)
+**         2450123.5           0.2       (date & time method)
+**
+**     The JD method is the most natural and convenient to use in cases
+**     where the loss of several decimal digits of resolution is
+**     acceptable.  The J2000 and MJD methods are good compromises
+**     between resolution and convenience.  For UT, the date & time
+**     method is best matched to the algorithm that is used by the Earth
+**     Rotation Angle function, called internally:  maximum precision is
+**     delivered when the uta argument is for 0hrs UT1 on the day in
+**     question and the utb argument lies in the range 0 to 1, or vice
+**     versa.
+**
+**  2) The result is compatible with the IAU 2000 resolutions, except
+**     that accuracy has been compromised for the sake of speed and
+**     convenience in two respects:
+**
+**     . UT is used instead of TDB (or TT) to compute the precession
+**       component of GMST and the equation of the equinoxes.  This
+**       results in errors of order 0.1 mas at present.
+**
+**     . The IAU 2000B abridged nutation model (McCarthy & Luzum, 2001)
+**       is used, introducing errors of up to 1 mas.
+**
+**  3) This GAST is compatible with the IAU 2000 resolutions and must be
+**     used only in conjunction with other IAU 2000 compatible
+**     components such as precession-nutation.
+**
+**  4) The result is returned in the range 0 to 2pi.
+**
+**  5) The algorithm is from Capitaine et al. (2003) and IERS
+**     Conventions 2003.
+**
+**  Called:
+**     eraGmst00    Greenwich mean sidereal time, IAU 2000
+**     eraEe00b     equation of the equinoxes, IAU 2000B
+**     eraAnp       normalize angle into range 0 to 2pi
+**
+**  References:
+**
+**     Capitaine, N., Wallace, P.T. and McCarthy, D.D., "Expressions to
+**     implement the IAU 2000 definition of UT1", Astronomy &
+**     Astrophysics, 406, 1135-1149 (2003)
+**
+**     McCarthy, D.D. & Luzum, B.J., "An abridged model of the
+**     precession-nutation of the celestial pole", Celestial Mechanics &
+**     Dynamical Astronomy, 85, 37-49 (2003)
+**
+**     McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
+**     IERS Technical Note No. 32, BKG (2004)
+**
+**  Copyright (C) 2013-2016, NumFOCUS Foundation.
+**  Derived, with permission, from the SOFA library.  See notes at end of file.
+*/
+{
+   double gmst00, ee00b, gst;
+
+
+   gmst00 = eraGmst00(uta, utb, uta, utb);
+   ee00b = eraEe00b(uta, utb);
+   gst = eraAnp(gmst00 + ee00b);
+
+   return gst;
+
+}
+/*----------------------------------------------------------------------
+**  
+**  
+**  Copyright (C) 2013-2016, NumFOCUS Foundation.
+**  All rights reserved.
+**  
+**  This library is derived, with permission, from the International
+**  Astronomical Union's "Standards of Fundamental Astronomy" library,
+**  available from http://www.iausofa.org.
+**  
+**  The ERFA version is intended to retain identical functionality to
+**  the SOFA library, but made distinct through different function and
+**  file names, as set out in the SOFA license conditions.  The SOFA
+**  original has a role as a reference standard for the IAU and IERS,
+**  and consequently redistribution is permitted only in its unaltered
+**  state.  The ERFA version is not subject to this restriction and
+**  therefore can be included in distributions which do not support the
+**  concept of "read only" software.
+**  
+**  Although the intent is to replicate the SOFA API (other than
+**  replacement of prefix names) and results (with the exception of
+**  bugs;  any that are discovered will be fixed), SOFA is not
+**  responsible for any errors found in this version of the library.
+**  
+**  If you wish to acknowledge the SOFA heritage, please acknowledge
+**  that you are using a library derived from SOFA, rather than SOFA
+**  itself.
+**  
+**  
+**  TERMS AND CONDITIONS
+**  
+**  Redistribution and use in source and binary forms, with or without
+**  modification, are permitted provided that the following conditions
+**  are met:
+**  
+**  1 Redistributions of source code must retain the above copyright
+**    notice, this list of conditions and the following disclaimer.
+**  
+**  2 Redistributions in binary form must reproduce the above copyright
+**    notice, this list of conditions and the following disclaimer in
+**    the documentation and/or other materials provided with the
+**    distribution.
+**  
+**  3 Neither the name of the Standards Of Fundamental Astronomy Board,
+**    the International Astronomical Union nor the names of its
+**    contributors may be used to endorse or promote products derived
+**    from this software without specific prior written permission.
+**  
+**  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+**  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+**  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+**  FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+**  COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+**  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+**  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+**  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+**  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+**  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+**  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+**  POSSIBILITY OF SUCH DAMAGE.
+**  
+*/