sofars 0.6.0

Pure Rust implementation of the IAU SOFA library
Documentation 
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use super::pn00b::pn00b;

///  Form the matrix of nutation for a given date, IAU 2000B model.
///
///  This function is part of the International Astronomical Union's
///  SOFA (Standards of Fundamental Astronomy) software collection.
///
///  Status:  support function.
///
///  Given:
///     date1,date2  double         TT as a 2-part Julian Date (Note 1)
///
///  Returned (function value):
///     rmatn        [[f64; 3]; 3]   nutation matrix
///
///  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 matrix operates in the sense V(true) = rmatn * V(mean), where
///     the p-vector V(true) is with respect to the true equatorial triad
///     of date and the p-vector V(mean) is with respect to the mean
///     equatorial triad of date.
///
///  3) The present function is faster, but slightly less accurate (about
///     1 mas), than the iauNum00a function.
///
///  Called:
///     iauPn00b     bias/precession/nutation, IAU 2000B
///
///  Reference:
///
///     Explanatory Supplement to the Astronomical Almanac,
///     P. Kenneth Seidelmann (ed), University Science Books (1992),
///     Section 3.222-3 (p114).
pub fn num00b(date1: f64, date2: f64) -> [[f64; 3]; 3] {
    /* Obtain the required matrix (discarding other results). */
    let (_, _, _, _, _, _, rmatn, _) = pn00b(date1, date2);
    rmatn
}