rfa 0.5.9

A port ERFA to Rust.
Documentation 
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use super::{nut06a::*, pn06::*,};
///  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
///
///  This revision:  2021 May 11
pub fn pn06a(date1: f64, date2: f64,
    dpsi: &mut f64, deps: &mut f64, epsa: &mut f64,
    rb: &mut [[f64; 3];3], rp: &mut [[f64; 3];3], rbp: &mut [[f64; 3];3],
    rn: &mut [[f64; 3];3], rbpn: &mut [[f64; 3];3])
{
    /* Nutation. */
       nut06a(date1, date2, dpsi, deps);
    
    /* Remaining results. */
       pn06(date1, date2, *dpsi, *deps, epsa, rb, rp, rbp, rn, rbpn);
    
    /* Finished. */
    
}