/rust/registry/src/index.crates.io-1949cf8c6b5b557f/sofars-0.6.1/src/pnp/num06a.rs

Source
use super::{numat, nut06a, obl06};

///  Form the matrix of nutation for a given date, IAU 2006/2000A 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.
///
///  Called:
///     iauObl06     mean obliquity, IAU 2006
///     iauNut06a    nutation, IAU 2006/2000A
///     iauNumat     form nutation matrix
///
///  Reference:
///
///     Explanatory Supplement to the Astronomical Almanac,
///     P. Kenneth Seidelmann (ed), University Science Books (1992),
///     Section 3.222-3 (p114).
pub fn num06a(date1: f64, date2: f64) -> [[f64; 3]; 3] {
    /* Mean obliquity. */
    let eps = obl06(date1, date2);

    /* Nutation components. */
    let (dp, de) = nut06a(date1, date2);

    /* Nutation matrix. */
    numat(eps, dp, de)
}

Coverage Report

Created: 2026-05-16 06:09

Line	Count	Source
1		use super::{numat, nut06a, obl06};
2
3		/// Form the matrix of nutation for a given date, IAU 2006/2000A model.
4		///
5		/// This function is part of the International Astronomical Union's
6		/// SOFA (Standards of Fundamental Astronomy) software collection.
7		///
8		/// Status: support function.
9		///
10		/// Given:
11		/// date1,date2 double TT as a 2-part Julian Date (Note 1)
12		///
13		/// Returned (function value):
14		/// rmatn [[f64; 3]; 3] nutation matrix
15		///
16		/// Notes:
17		///
18		/// 1) The TT date date1+date2 is a Julian Date, apportioned in any
19		/// convenient way between the two arguments. For example,
20		/// JD(TT)=2450123.7 could be expressed in any of these ways,
21		/// among others:
22		///
23		/// date1 date2
24		///
25		/// 2450123.7 0.0 (JD method)
26		/// 2451545.0 -1421.3 (J2000 method)
27		/// 2400000.5 50123.2 (MJD method)
28		/// 2450123.5 0.2 (date & time method)
29		///
30		/// The JD method is the most natural and convenient to use in
31		/// cases where the loss of several decimal digits of resolution
32		/// is acceptable. The J2000 method is best matched to the way
33		/// the argument is handled internally and will deliver the
34		/// optimum resolution. The MJD method and the date & time methods
35		/// are both good compromises between resolution and convenience.
36		///
37		/// 2) The matrix operates in the sense V(true) = rmatn * V(mean), where
38		/// the p-vector V(true) is with respect to the true equatorial triad
39		/// of date and the p-vector V(mean) is with respect to the mean
40		/// equatorial triad of date.
41		///
42		/// Called:
43		/// iauObl06 mean obliquity, IAU 2006
44		/// iauNut06a nutation, IAU 2006/2000A
45		/// iauNumat form nutation matrix
46		///
47		/// Reference:
48		///
49		/// Explanatory Supplement to the Astronomical Almanac,
50		/// P. Kenneth Seidelmann (ed), University Science Books (1992),
51		/// Section 3.222-3 (p114).
52	0	pub fn num06a(date1: f64, date2: f64) -> [[f64; 3]; 3] {
53		/* Mean obliquity. */
54	0	let eps = obl06(date1, date2);
55
56		/* Nutation components. */
57	0	let (dp, de) = nut06a(date1, date2);
58
59		/* Nutation matrix. */
60	0	numat(eps, dp, de)
61	0	}