Merge commit 'd26ed8388f100a12996c0b92a98040ef2ba7fa8e' as 'ast'

1 files changed, 151 insertions, 0 deletions

diff --git a/ast/erfa/pr00.c b/ast/erfa/pr00.c
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+#include "erfa.h"
+
+void eraPr00(double date1, double date2, double *dpsipr, double *depspr)
+/*
+**  - - - - - - - -
+**   e r a P r 0 0
+**  - - - - - - - -
+**
+**  Precession-rate part of the IAU 2000 precession-nutation models
+**  (part of MHB2000).
+**
+**  Given:
+**     date1,date2    double  TT as a 2-part Julian Date (Note 1)
+**
+**  Returned:
+**     dpsipr,depspr  double  precession corrections (Notes 2,3)
+**
+**  Notes:
+**
+**  1) The TT date date1+date2 is a Julian Date, apportioned in any
+**     convenient way between the two arguments.  For example,
+**     JD(TT)=2450123.7 could be expressed in any of these ways,
+**     among others:
+**
+**            date1          date2
+**
+**         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 method is best matched to the way
+**     the argument is handled internally and will deliver the
+**     optimum resolution.  The MJD method and the date & time methods
+**     are both good compromises between resolution and convenience.
+**
+**  2) The precession adjustments are expressed as "nutation
+**     components", corrections in longitude and obliquity with respect
+**     to the J2000.0 equinox and ecliptic.
+**
+**  3) Although the precession adjustments are stated to be with respect
+**     to Lieske et al. (1977), the MHB2000 model does not specify which
+**     set of Euler angles are to be used and how the adjustments are to
+**     be applied.  The most literal and straightforward procedure is to
+**     adopt the 4-rotation epsilon_0, psi_A, omega_A, xi_A option, and
+**     to add dpsipr to psi_A and depspr to both omega_A and eps_A.
+**
+**  4) This is an implementation of one aspect of the IAU 2000A nutation
+**     model, formally adopted by the IAU General Assembly in 2000,
+**     namely MHB2000 (Mathews et al. 2002).
+**
+**  References:
+**
+**     Lieske, J.H., Lederle, T., Fricke, W. & Morando, B., "Expressions
+**     for the precession quantities based upon the IAU (1976) System of
+**     Astronomical Constants", Astron.Astrophys., 58, 1-16 (1977)
+**
+**     Mathews, P.M., Herring, T.A., Buffet, B.A., "Modeling of nutation
+**     and precession   New nutation series for nonrigid Earth and
+**     insights into the Earth's interior", J.Geophys.Res., 107, B4,
+**     2002.  The MHB2000 code itself was obtained on 9th September 2002
+**     from ftp://maia.usno.navy.mil/conv2000/chapter5/IAU2000A.
+**
+**     Wallace, P.T., "Software for Implementing the IAU 2000
+**     Resolutions", in IERS Workshop 5.1 (2002).
+**
+**  Copyright (C) 2013-2016, NumFOCUS Foundation.
+**  Derived, with permission, from the SOFA library.  See notes at end of file.
+*/
+{
+   double t;
+
+/* Precession and obliquity corrections (radians per century) */
+   static const double PRECOR = -0.29965 * ERFA_DAS2R,
+                       OBLCOR = -0.02524 * ERFA_DAS2R;
+
+
+/* Interval between fundamental epoch J2000.0 and given date (JC). */
+   t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;
+
+/* Precession rate contributions with respect to IAU 1976/80. */
+   *dpsipr = PRECOR * t;
+   *depspr = OBLCOR * t;
+
+   return;
+
+}
+/*----------------------------------------------------------------------
+**  
+**  
+**  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.
+**  
+*/