File Coverage

erfasrc/src/bp00.c

Criterion	Covered	Total	%
statement	0	21	0.0
branch			n/a
condition			n/a
subroutine			n/a
pod			n/a
total	0	21	0.0

line	stmt	code
1		#include "erfa.h"
2
3	0	void eraBp00(double date1, double date2,
4		double rb[3][3], double rp[3][3], double rbp[3][3])
5		/*
6		** - - - - - - - -
7		** e r a B p 0 0
8		** - - - - - - - -
9		**
10		** Frame bias and precession, IAU 2000.
11		**
12		** Given:
13		** date1,date2 double TT as a 2-part Julian Date (Note 1)
14		**
15		** Returned:
16		** rb double[3][3] frame bias matrix (Note 2)
17		** rp double[3][3] precession matrix (Note 3)
18		** rbp double[3][3] bias-precession matrix (Note 4)
19		**
20		** Notes:
21		**
22		** 1) The TT date date1+date2 is a Julian Date, apportioned in any
23		** convenient way between the two arguments. For example,
24		** JD(TT)=2450123.7 could be expressed in any of these ways,
25		** among others:
26		**
27		** date1 date2
28		**
29		** 2450123.7 0.0 (JD method)
30		** 2451545.0 -1421.3 (J2000 method)
31		** 2400000.5 50123.2 (MJD method)
32		** 2450123.5 0.2 (date & time method)
33		**
34		** The JD method is the most natural and convenient to use in
35		** cases where the loss of several decimal digits of resolution
36		** is acceptable. The J2000 method is best matched to the way
37		** the argument is handled internally and will deliver the
38		** optimum resolution. The MJD method and the date & time methods
39		** are both good compromises between resolution and convenience.
40		**
41		** 2) The matrix rb transforms vectors from GCRS to mean J2000.0 by
42		** applying frame bias.
43		**
44		** 3) The matrix rp transforms vectors from J2000.0 mean equator and
45		** equinox to mean equator and equinox of date by applying
46		** precession.
47		**
48		** 4) The matrix rbp transforms vectors from GCRS to mean equator and
49		** equinox of date by applying frame bias then precession. It is
50		** the product rp x rb.
51		**
52		** 5) It is permissible to re-use the same array in the returned
53		** arguments. The arrays are filled in the order given.
54		**
55		** Called:
56		** eraBi00 frame bias components, IAU 2000
57		** eraPr00 IAU 2000 precession adjustments
58		** eraIr initialize r-matrix to identity
59		** eraRx rotate around X-axis
60		** eraRy rotate around Y-axis
61		** eraRz rotate around Z-axis
62		** eraCr copy r-matrix
63		** eraRxr product of two r-matrices
64		**
65		** Reference:
66		** "Expressions for the Celestial Intermediate Pole and Celestial
67		** Ephemeris Origin consistent with the IAU 2000A precession-
68		** nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
69		**
70		** n.b. The celestial ephemeris origin (CEO) was renamed "celestial
71		** intermediate origin" (CIO) by IAU 2006 Resolution 2.
72		**
73		** Copyright (C) 2013-2020, NumFOCUS Foundation.
74		** Derived, with permission, from the SOFA library. See notes at end of file.
75		*/
76		{
77		/* J2000.0 obliquity (Lieske et al. 1977) */
78		const double EPS0 = 84381.448 * ERFA_DAS2R;
79
80		double t, dpsibi, depsbi, dra0, psia77, oma77, chia,
81		dpsipr, depspr, psia, oma, rbw[3][3];
82
83
84		/* Interval between fundamental epoch J2000.0 and current date (JC). */
85	0	t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;
86
87		/* Frame bias. */
88	0	eraBi00(&dpsibi, &depsbi, &dra0);
89
90		/* Precession angles (Lieske et al. 1977) */
91	0	psia77 = (5038.7784 + (-1.07259 + (-0.001147) * t) * t) * t * ERFA_DAS2R;
92	0	oma77 = EPS0 + ((0.05127 + (-0.007726) * t) * t) * t * ERFA_DAS2R;
93	0	chia = ( 10.5526 + (-2.38064 + (-0.001125) * t) * t) * t * ERFA_DAS2R;
94
95		/* Apply IAU 2000 precession corrections. */
96	0	eraPr00(date1, date2, &dpsipr, &depspr);
97	0	psia = psia77 + dpsipr;
98	0	oma = oma77 + depspr;
99
100		/* Frame bias matrix: GCRS to J2000.0. */
101	0	eraIr(rbw);
102	0	eraRz(dra0, rbw);
103	0	eraRy(dpsibi*sin(EPS0), rbw);
104	0	eraRx(-depsbi, rbw);
105	0	eraCr(rbw, rb);
106
107		/* Precession matrix: J2000.0 to mean of date. */
108	0	eraIr(rp);
109	0	eraRx(EPS0, rp);
110	0	eraRz(-psia, rp);
111	0	eraRx(-oma, rp);
112	0	eraRz(chia, rp);
113
114		/* Bias-precession matrix: GCRS to mean of date. */
115	0	eraRxr(rp, rbw, rbp);
116
117	0	return;
118
119		}
120		/*----------------------------------------------------------------------
121		**
122		**
123		** Copyright (C) 2013-2020, NumFOCUS Foundation.
124		** All rights reserved.
125		**
126		** This library is derived, with permission, from the International
127		** Astronomical Union's "Standards of Fundamental Astronomy" library,
128		** available from http://www.iausofa.org.
129		**
130		** The ERFA version is intended to retain identical functionality to
131		** the SOFA library, but made distinct through different function and
132		** file names, as set out in the SOFA license conditions. The SOFA
133		** original has a role as a reference standard for the IAU and IERS,
134		** and consequently redistribution is permitted only in its unaltered
135		** state. The ERFA version is not subject to this restriction and
136		** therefore can be included in distributions which do not support the
137		** concept of "read only" software.
138		**
139		** Although the intent is to replicate the SOFA API (other than
140		** replacement of prefix names) and results (with the exception of
141		** bugs; any that are discovered will be fixed), SOFA is not
142		** responsible for any errors found in this version of the library.
143		**
144		** If you wish to acknowledge the SOFA heritage, please acknowledge
145		** that you are using a library derived from SOFA, rather than SOFA
146		** itself.
147		**
148		**
149		** TERMS AND CONDITIONS
150		**
151		** Redistribution and use in source and binary forms, with or without
152		** modification, are permitted provided that the following conditions
153		** are met:
154		**
155		** 1 Redistributions of source code must retain the above copyright
156		** notice, this list of conditions and the following disclaimer.
157		**
158		** 2 Redistributions in binary form must reproduce the above copyright
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162		**
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164		** the International Astronomical Union nor the names of its
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