LSSTApplications  12.1-5-gbdcc3ab,15.0+10,15.0+24,15.0-1-g19261fa+15,15.0-1-g60afb23+24,15.0-1-g615e0bb+16,15.0-1-g6668b0b+6,15.0-1-g788a293+24,15.0-1-ga91101e+24,15.0-1-gae1598d+9,15.0-1-gd076f1f+22,15.0-1-gdf18595+3,15.0-1-gf4f1c34+9,15.0-11-g7db6e543+2,15.0-12-g3681e7a+2,15.0-13-g5992896b,15.0-13-g7441b25,15.0-2-g100d730+17,15.0-2-g1f9c9cf+2,15.0-2-gf38729e+19,15.0-27-g6268be7ac,15.0-3-g11fe1a0+11,15.0-3-g52118bc+2,15.0-3-g707930d+1,15.0-3-g7b706ea+2,15.0-3-g9103c06+9,15.0-3-gd3cbb57+1,15.0-4-g535e784+8,15.0-4-g92ca6c3+2,15.0-4-gf906033,15.0-5-g23e394c+12,15.0-5-g993f083+4,15.0-5-gf788cd9+2,15.0-6-gdf787ba+1,15.0-6-gfa9b38f+2,15.0-7-g949993c+1,15.0-7-gbf600c9+3,15.0-8-gc213bcc,w.2018.20
LSSTDataManagementBasePackage
constants.h
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1 /*
2  * LSST Data Management System
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5  * This product includes software developed by the
6  * LSST Project (http://www.lsst.org/).
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22 
23 #ifndef LSST_SPHGEOM_CONSTANTS_H_
24 #define LSST_SPHGEOM_CONSTANTS_H_
25 
28 
29 
30 namespace lsst {
31 namespace sphgeom {
32 
33 // Note: given a compiler that does correctly rounded decimal to
34 // binary floating point conversions, PI = 0x1.921fb54442d18p1 in
35 // IEEE double precision format. This is less than π.
36 constexpr double PI = 3.1415926535897932384626433832795;
37 constexpr double ONE_OVER_PI = 0.318309886183790671537767526745;
38 constexpr double RAD_PER_DEG = 0.0174532925199432957692369076849;
39 constexpr double DEG_PER_RAD = 57.2957795130823208767981548141;
40 
41 // The maximum error of std::asin in IEEE double precision arithmetic,
42 // assuming 1 ulp of error in its argument, is about
43 // π/2 - arcsin (1 - 2⁻⁵³), or a little less than 1.5e-8 radians
44 // (3.1 milliarcsec).
45 constexpr double MAX_ASIN_ERROR = 1.5e-8;
46 
47 // The computation of squared chord length between two unit vectors
48 // involves 8 elementary operations on numbers with magnitude ≤ 4. Its
49 // maximum error can be shown to be < 2.5e-15.
50 constexpr double MAX_SQUARED_CHORD_LENGTH_ERROR = 2.5e-15;
51 
52 // The largest value ε such that 1 + ε rounds to 1 in IEEE double
53 // precision, assuming round-to-nearest-ties-to-even rounding.
54 constexpr double EPSILON = 1.1102230246251565e-16;
55 
56 }} // namespace lsst::sphgeom
57 
58 #endif // LSST_SPHGEOM_CONSTANTS_H_
constexpr double EPSILON
Definition: constants.h:54
constexpr double ONE_OVER_PI
Definition: constants.h:37
constexpr double DEG_PER_RAD
Definition: constants.h:39
constexpr double MAX_SQUARED_CHORD_LENGTH_ERROR
Definition: constants.h:50
constexpr double MAX_ASIN_ERROR
Definition: constants.h:45
A base class for image defects.
Definition: cameraGeom.dox:3
constexpr double PI
Definition: constants.h:36
constexpr double RAD_PER_DEG
Definition: constants.h:38