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utils.h
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1/*
2 * This file is part of sphgeom.
3 *
4 * Developed for the LSST Data Management System.
5 * This product includes software developed by the LSST Project
6 * (http://www.lsst.org).
7 * See the COPYRIGHT file at the top-level directory of this distribution
8 * for details of code ownership.
9 *
10 * This software is dual licensed under the GNU General Public License and also
11 * under a 3-clause BSD license. Recipients may choose which of these licenses
12 * to use; please see the files gpl-3.0.txt and/or bsd_license.txt,
13 * respectively. If you choose the GPL option then the following text applies
14 * (but note that there is still no warranty even if you opt for BSD instead):
15 *
16 * This program is free software: you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License as published by
18 * the Free Software Foundation, either version 3 of the License, or
19 * (at your option) any later version.
20 *
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 * GNU General Public License for more details.
25 *
26 * You should have received a copy of the GNU General Public License
27 * along with this program. If not, see <http://www.gnu.org/licenses/>.
28 */
29
30#ifndef LSST_SPHGEOM_UTILS_H_
31#define LSST_SPHGEOM_UTILS_H_
32
35
36#include "Angle.h"
37
38
39namespace lsst {
40namespace sphgeom {
41
42// Forward declarations
43class Vector3d;
44class UnitVector3d;
45
52double getMinSquaredChordLength(Vector3d const & v,
53 Vector3d const & a,
54 Vector3d const & b,
55 Vector3d const & n);
56
62double getMaxSquaredChordLength(Vector3d const & v,
63 Vector3d const & a,
64 Vector3d const & b,
65 Vector3d const & n);
66
70 return abs(x - c);
71}
72
76 Angle a = getMinAngleToCircle(x, c);
77 if (abs(x) <= abs(c)) {
78 return a + Angle(PI) - 2.0 * abs(c);
79 }
80 if (a < abs(x)) {
81 return Angle(PI) - 2.0 * abs(c) - a;
82 }
83 return Angle(PI) + 2.0 * abs(c) - a;
84}
85
89Vector3d getWeightedCentroid(UnitVector3d const & v0,
90 UnitVector3d const & v1,
91 UnitVector3d const & v2);
92
93}} // namespace lsst::sphgeom
94
95#endif // LSST_SPHGEOM_UTILS_H_
Angle represents an angle in radians.
Definition Angle.h:50
UnitVector3d is a unit vector in ℝ³ with components stored in double precision.
Vector3d is a vector in ℝ³ with components stored in double precision.
Definition Vector3d.h:51
Angle getMaxAngleToCircle(Angle x, Angle c)
getMaxAngleToCircle returns the maximum angular separation between a point at latitude x and the poin...
Definition utils.h:75
Angle getMinAngleToCircle(Angle x, Angle c)
getMinAngleToCircle returns the minimum angular separation between a point at latitude x and the poin...
Definition utils.h:69
Angle abs(Angle const &a)
Definition Angle.h:113
double getMaxSquaredChordLength(Vector3d const &v, Vector3d const &a, Vector3d const &b, Vector3d const &n)
Let p be the unit vector furthest from v that lies on the plane with normal n in the direction of the...
Definition utils.cc:65
Vector3d getWeightedCentroid(UnitVector3d const &v0, UnitVector3d const &v1, UnitVector3d const &v2)
getWeightedCentroid returns the center of mass of the given spherical triangle (assuming a uniform ma...
Definition utils.cc:86
double getMinSquaredChordLength(Vector3d const &v, Vector3d const &a, Vector3d const &b, Vector3d const &n)
Let p be the unit vector closest to v that lies on the plane with normal n in the direction of the cr...
Definition utils.cc:43
constexpr double PI
Definition constants.h:43
This file declares a class for representing angles.