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+#include "erfa.h"
+
+void eraPn06a(double date1, double date2,
+ double *dpsi, double *deps, double *epsa,
+ double rb[3][3], double rp[3][3], double rbp[3][3],
+ double rn[3][3], double rbpn[3][3])
+/*
+** - - - - - - - - -
+** e r a P n 0 6 a
+** - - - - - - - - -
+**
+** Precession-nutation, IAU 2006/2000A models: a multi-purpose function,
+** supporting classical (equinox-based) use directly and CIO-based use
+** indirectly.
+**
+** Given:
+** date1,date2 double TT as a 2-part Julian Date (Note 1)
+**
+** Returned:
+** dpsi,deps double nutation (Note 2)
+** epsa double mean obliquity (Note 3)
+** rb double[3][3] frame bias matrix (Note 4)
+** rp double[3][3] precession matrix (Note 5)
+** rbp double[3][3] bias-precession matrix (Note 6)
+** rn double[3][3] nutation matrix (Note 7)
+** rbpn double[3][3] GCRS-to-true matrix (Notes 8,9)
+**
+** 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 nutation components (luni-solar + planetary, IAU 2000A) in
+** longitude and obliquity are in radians and with respect to the
+** equinox and ecliptic of date. Free core nutation is omitted;
+** for the utmost accuracy, use the eraPn06 function, where the
+** nutation components are caller-specified.
+**
+** 3) The mean obliquity is consistent with the IAU 2006 precession.
+**
+** 4) The matrix rb transforms vectors from GCRS to mean J2000.0 by
+** applying frame bias.
+**
+** 5) The matrix rp transforms vectors from mean J2000.0 to mean of
+** date by applying precession.
+**
+** 6) The matrix rbp transforms vectors from GCRS to mean of date by
+** applying frame bias then precession. It is the product rp x rb.
+**
+** 7) The matrix rn transforms vectors from mean of date to true of
+** date by applying the nutation (luni-solar + planetary).
+**
+** 8) The matrix rbpn transforms vectors from GCRS to true of date
+** (CIP/equinox). It is the product rn x rbp, applying frame bias,
+** precession and nutation in that order.
+**
+** 9) The X,Y,Z coordinates of the IAU 2006/2000A Celestial
+** Intermediate Pole are elements (3,1-3) of the GCRS-to-true
+** matrix, i.e. rbpn[2][0-2].
+**
+** 10) It is permissible to re-use the same array in the returned
+** arguments. The arrays are filled in the stated order.
+**
+** Called:
+** eraNut06a nutation, IAU 2006/2000A
+** eraPn06 bias/precession/nutation results, IAU 2006
+**
+** Reference:
+**
+** Capitaine, N. & Wallace, P.T., 2006, Astron.Astrophys. 450, 855
+**
+** Copyright (C) 2013-2016, NumFOCUS Foundation.
+** Derived, with permission, from the SOFA library. See notes at end of file.
+*/
+{
+/* Nutation. */
+ eraNut06a(date1, date2, dpsi, deps);
+
+/* Remaining results. */
+ eraPn06(date1, date2, *dpsi, *deps, epsa, rb, rp, rbp, rn, rbpn);
+
+ 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.
+**
+*/