/rust/registry/src/index.crates.io-1949cf8c6b5b557f/sofars-0.6.2/src/pnp/pn00.rs

Source
use crate::vm::rxr;

use super::{bp00, numat, obl80, pr00};

///  Bias/precession/nutation results, IAU 2000
///
///  Precession-nutation, IAU 2000 model:  a multi-purpose function,
///  supporting classical (equinox-based) use directly and CIO-based
///  use indirectly.
///
///  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)
///     dpsi,deps    double          nutation (Note 2)
///
///  Returned (function value):
///     (epsa, rb, rp, rbp, rn, rbpn) (f64, [[f64; 3]; 3], [[f64; 3]; 3], [[f64; 3]; 3], [[f64; 3]; 3], [[f64; 3]; 3])
///
///     epsa         mean obliquity (Note 3)
///     rb           frame bias matrix (Note 4)
///     rp           precession matrix (Note 5)
///     rbp          bias-precession matrix (Note 6)
///     rn           nutation matrix (Note 7)
///     rbpn         GCRS-to-true matrix (Note 8)
///
///  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:
///
///  ```text
///            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 caller is responsible for providing the nutation components;
///     they are in longitude and obliquity, in radians and are with
///     respect to the equinox and ecliptic of date.  For high-accuracy
///     applications, free core nutation should be included as well as
///     any other relevant corrections to the position of the CIP.
///
///  3) The returned mean obliquity is consistent with the IAU 2000
///     precession-nutation models.
///
///  4) The matrix rb transforms vectors from GCRS to J2000.0 mean
///     equator and equinox by applying frame bias.
///
///  5) The matrix rp transforms vectors from J2000.0 mean equator and
///     equinox to mean equator and equinox of date by applying
///     precession.
///
///  6) The matrix rbp transforms vectors from GCRS to mean equator and
///     equinox of date by applying frame bias then precession.  It is
///     the product rp x rb.
///
///  7) The matrix rn transforms vectors from mean equator and equinox of
///     date to true equator and equinox of date by applying the nutation
///     (luni-solar + planetary).
///
///  8) The matrix rbpn transforms vectors from GCRS to true equator and
///     equinox of date.  It is the product rn x rbp, applying frame
///     bias, precession and nutation in that order.
///
///  Called:
///     iauPr00      IAU 2000 precession adjustments
///     iauObl80     mean obliquity, IAU 1980
///     iauBp00      frame bias and precession matrices, IAU 2000
///     iauCr        copy r-matrix
///     iauNumat     form nutation matrix
///     iauRxr       product of two r-matrices
///
///  Reference:
///
///     Capitaine, N., Chapront, J., Lambert, S. and Wallace, P.,
///     "Expressions for the Celestial Intermediate Pole and Celestial
///     Ephemeris Origin consistent with the IAU 2000A precession-
///     nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
///
///     n.b. The celestial ephemeris origin (CEO) was renamed "celestial
///          intermediate origin" (CIO) by IAU 2006 Resolution 2.
pub fn pn00(
    date1: f64,
    date2: f64,
    dpsi: f64,
    deps: f64,
) -> (
    f64,
    [[f64; 3]; 3],
    [[f64; 3]; 3],
    [[f64; 3]; 3],
    [[f64; 3]; 3],
    [[f64; 3]; 3],
) {
    let mut rbpn = [[0.0; 3]; 3];

    /* IAU 2000 precession-rate adjustments. */
    let (_, depspr) = pr00(date1, date2);

    /* Mean obliquity, consistent with IAU 2000 precession-nutation. */
    let epsa = obl80(date1, date2) + depspr;

    /* Frame bias and precession matrices and their product. */
    let (rb, rp, rbp) = bp00(date1, date2);

    /* Nutation matrix. */
    let rn = numat(epsa, dpsi, deps);

    /* Bias-precession-nutation matrix (classical). */
    rxr(&rn, &rbp, &mut rbpn);

    (epsa, rb, rp, rbp, rn, rbpn)
}

Coverage Report

Created: 2026-10-28 06:40

Line	Count	Source
1		use crate::vm::rxr;
2
3		use super::{bp00, numat, obl80, pr00};
4
5		/// Bias/precession/nutation results, IAU 2000
6		///
7		/// Precession-nutation, IAU 2000 model: a multi-purpose function,
8		/// supporting classical (equinox-based) use directly and CIO-based
9		/// use indirectly.
10		///
11		/// This function is part of the International Astronomical Union's
12		/// SOFA (Standards of Fundamental Astronomy) software collection.
13		///
14		/// Status: support function.
15		///
16		/// Given:
17		/// date1,date2 double TT as a 2-part Julian Date (Note 1)
18		/// dpsi,deps double nutation (Note 2)
19		///
20		/// Returned (function value):
21		/// (epsa, rb, rp, rbp, rn, rbpn) (f64, [[f64; 3]; 3], [[f64; 3]; 3], [[f64; 3]; 3], [[f64; 3]; 3], [[f64; 3]; 3])
22		///
23		/// epsa mean obliquity (Note 3)
24		/// rb frame bias matrix (Note 4)
25		/// rp precession matrix (Note 5)
26		/// rbp bias-precession matrix (Note 6)
27		/// rn nutation matrix (Note 7)
28		/// rbpn GCRS-to-true matrix (Note 8)
29		///
30		/// Notes:
31		///
32		/// 1) The TT date date1+date2 is a Julian Date, apportioned in any
33		/// convenient way between the two arguments. For example,
34		/// JD(TT)=2450123.7 could be expressed in any of these ways,
35		/// among others:
36		///
37		/// ```text
38		/// date1 date2
39		///
40		/// 2450123.7 0.0 (JD method)
41		/// 2451545.0 -1421.3 (J2000 method)
42		/// 2400000.5 50123.2 (MJD method)
43		/// 2450123.5 0.2 (date & time method)
44		/// ```
45		///
46		/// The JD method is the most natural and convenient to use in
47		/// cases where the loss of several decimal digits of resolution
48		/// is acceptable. The J2000 method is best matched to the way
49		/// the argument is handled internally and will deliver the
50		/// optimum resolution. The MJD method and the date & time methods
51		/// are both good compromises between resolution and convenience.
52		///
53		/// 2) The caller is responsible for providing the nutation components;
54		/// they are in longitude and obliquity, in radians and are with
55		/// respect to the equinox and ecliptic of date. For high-accuracy
56		/// applications, free core nutation should be included as well as
57		/// any other relevant corrections to the position of the CIP.
58		///
59		/// 3) The returned mean obliquity is consistent with the IAU 2000
60		/// precession-nutation models.
61		///
62		/// 4) The matrix rb transforms vectors from GCRS to J2000.0 mean
63		/// equator and equinox by applying frame bias.
64		///
65		/// 5) The matrix rp transforms vectors from J2000.0 mean equator and
66		/// equinox to mean equator and equinox of date by applying
67		/// precession.
68		///
69		/// 6) The matrix rbp transforms vectors from GCRS to mean equator and
70		/// equinox of date by applying frame bias then precession. It is
71		/// the product rp x rb.
72		///
73		/// 7) The matrix rn transforms vectors from mean equator and equinox of
74		/// date to true equator and equinox of date by applying the nutation
75		/// (luni-solar + planetary).
76		///
77		/// 8) The matrix rbpn transforms vectors from GCRS to true equator and
78		/// equinox of date. It is the product rn x rbp, applying frame
79		/// bias, precession and nutation in that order.
80		///
81		/// Called:
82		/// iauPr00 IAU 2000 precession adjustments
83		/// iauObl80 mean obliquity, IAU 1980
84		/// iauBp00 frame bias and precession matrices, IAU 2000
85		/// iauCr copy r-matrix
86		/// iauNumat form nutation matrix
87		/// iauRxr product of two r-matrices
88		///
89		/// Reference:
90		///
91		/// Capitaine, N., Chapront, J., Lambert, S. and Wallace, P.,
92		/// "Expressions for the Celestial Intermediate Pole and Celestial
93		/// Ephemeris Origin consistent with the IAU 2000A precession-
94		/// nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
95		///
96		/// n.b. The celestial ephemeris origin (CEO) was renamed "celestial
97		/// intermediate origin" (CIO) by IAU 2006 Resolution 2.
98	0	pub fn pn00(
99	0	date1: f64,
100	0	date2: f64,
101	0	dpsi: f64,
102	0	deps: f64,
103	0	) -> (
104	0	f64,
105	0	[[f64; 3]; 3],
106	0	[[f64; 3]; 3],
107	0	[[f64; 3]; 3],
108	0	[[f64; 3]; 3],
109	0	[[f64; 3]; 3],
110	0	) {
111	0	let mut rbpn = [[0.0; 3]; 3];
112
113		/* IAU 2000 precession-rate adjustments. */
114	0	let (_, depspr) = pr00(date1, date2);
115
116		/* Mean obliquity, consistent with IAU 2000 precession-nutation. */
117	0	let epsa = obl80(date1, date2) + depspr;
118
119		/* Frame bias and precession matrices and their product. */
120	0	let (rb, rp, rbp) = bp00(date1, date2);
121
122		/* Nutation matrix. */
123	0	let rn = numat(epsa, dpsi, deps);
124
125		/* Bias-precession-nutation matrix (classical). */
126	0	rxr(&rn, &rbp, &mut rbpn);
127
128	0	(epsa, rb, rp, rbp, rn, rbpn)
129	0	}